Cryptic piperazine derivatives activated by knocking out the global regulator LaeA in Aspergillus flavipes

Genome sequencing on an intertidal zone-derived Aspergillus flavipes strain revealed its great potential to produce secondary metabolites. To activate the cryptic compounds of A. flavipes, the global regulator flLaeA was knocked out, leading to substantial up-regulation of the expression of two NRPS-like biosynthetic gene clusters in the ΔflLaeA mutant. With a scaled-up fermentation of the ΔflLaeA strain, five compounds, including two previously undescribed piperazine derivatives flavipamides A and B (1 and 2), along with three known compounds (3-5), were obtained by LC-MS guided isolation. The new compounds were elucidated by spectroscopic analysis and electronic circular dichroism (ECD) calculations, and the biosynthetic pathway was proposed on the bias of bioinformatic analysis and 13C isotope labeling evidence. This is the first report to access cryptic fungi secondary metabolites by inactivating global regulator LaeA and may provide a new approach to discovering new secondary metabolites by such genetic manipulation.

Healthcare-associated carbapenem-resistant Klebsiella pneumoniae infections are associated with higher mortality compared to carbapenem-susceptible K. pneumoniae infections in the intensive care unit: a retrospective cohort study

BACKGROUND

Klebsiella pneumoniae (KP) is an opportunistic pathogen causing severe pneumonia and sepsis. Carbapenem-resistant KP (CRKP) has become a major pathogen in many centres.

AIM

To investigate the association between carbapenem resistance and the mortality rate, length of stay, and hospital cost in patients with Klebsiella pneumoniae infection.

METHODS

The retrospective cohort study was conducted in the intensive care units of a large teaching tertiary hospital in southwest China between January 1st, 2020 and December 31st, 2022. To examine the impact of carbapenem resistance on mortality rates and economic burden, multivariate Cox regression and generalized linear models were constructed.

FINDINGS

The study included 282 adult patients with KP infection (135 CSKP; 147 CRKP). CRKP-infected patients demonstrated higher mortality risk (unadjusted hazard ratio (aHR): 1.980; 95% confidence interval (CI): 1.206-3.248; P = 0.007; aHR: 1.767; 95% CI: 1.038-3.005; P = 0.036) compared to CSKP-infected patients. Stratified analysis, according to type of KP infection, revealed that patients with healthcare-associated CRKP infection had a significantly higher mortality risk compared to those with CSKP infection (log-rank P = 0.015). Patients with CRKP infection had longer hospital stays than those infected with CSKP (adjusted mean: 38.74 vs 29.71 days; P = 0.003), and hospital-related expenses were notably higher among CRKP patients than CSKP patients (adjusted cost: £40,126.73 vs 25,713.74; P < 0.001).

CONCLUSION

CRKP infections increase mortality rates, prolong hospital stays, and raise healthcare costs. Healthcare facilities should adopt targeted strategies, including curtailing pre-infection hospitalization periods and managing medications more judiciously.

Identification of seven undescribed cucurbitacins in Cucumis sativus (cucumber) and their cytotoxic activity

Cucurbitacin C-type cucurbitacins that are only identified in Cucumis sativus (cucumber) are, in part, responsible for the health benefits and bitter flavor. Nevertheless, detailed information about those functional ingredients in cucumber is scarce. In this study, ten cucurbitacin C analogues including seven undescribed ones have been isolated from the bitter leaves of cucumber, in which six compounds showed growth inhibition capabilities against tumor cell lines HepG2, A549, DU145 and HCT116. Intriguingly, cucurbitacin C6 and C7 exhibited a significant inhibition effect compared to the positive control taxol (IC₅₀ = 1.86 ± 0.17 μM) on HepG2 cell line with IC₅₀ values of 10.06 ± 0.34 μM and 4.16 ± 0.42 μM, respectively. The mechanism of cucurbitacin-induced apoptosis is likely down-regulating the expression of caspase-related proteins. This work enlarges the knowledge of the cucurbitacins in cucumber and highlights the importance of cucumber as a source of specialized metabolites in the food and medicinal industries.

Attenuation of subchondral bone abnormal changes in osteoarthritis by inhibition of SDF-1 signaling

BACKGROUND

Current conservative treatments for osteoarthritis (OA) are largely symptoms control therapies. Further understanding on the pathological mechanisms of OA is crucial for new pharmacological intervention.

OBJECTIVE

In this study, we investigated the role of Stromal cell-derived factor-1(SDF-1) in regulating subchondral bone changes during the progression of OA.

METHODS

Clinical samples of different stages of OA severity were analyzed by histology staining, micro-CT, enzyme-linked immunosorbent assay (ELISA) and western blotting, to compare SDF-1 level in subchondral bone. The effects of SDF-1 on human mesenchymal stem cells (MSCs) osteogenic differentiation were evaluated. In vivo assessment was performed in an anterior cruciate ligament transaction plus medial meniscus resection in the SD rats. The OA rats received continuous infusion of AMD3100 (SDF-1 receptor blocker) in osmotic mini-pump implanted subcutaneously for 6 weeks. These rats were then terminated and subjected to the same in vitro assessments as human OA samples.

RESULTS

SDF-1 level was significantly elevated in the subchondral bone of human OA samples. In the cell studies, the results showed SDF-1 plays an important role in osteogenic differentiation of MSCs. In the OA animal studies, there were less cartilage damage in the AMD3100-treated group; microCT results showed that the subchondral bone formation was significantly reduced and so did the number of positive Nestin or Osterix cells in the subchondral bone region.

CONCLUSIONS

Higher level of SDF-1 may induce the subchondral bone abnormal changes in OA and inhibition of SDF-1 signaling could be a potential therapeutic approach for OA.

Lipid-mediated protein functionalization of electrospun polycaprolactone fibers

In this study, electrospun polycaprolactone (PCL) fibers are plasma-treated and chemically conjugated with cholesteryl succinyl silane (CSS). In addition to Raman spectroscopy, an immobilization study of DiO as a fluorescent probe of lipid membranes provides evidence supporting the CSS coating of plasma-treated PCL fibers. Further, anti-CD20 antibodies are used as a model protein to evaluate the potential of lipid-mediated protein immobilization as a mechanism to functionalize the CSS-PCL fiber scaffolds. Upon anti-CD20 functionalization, the CSS-PCL fiber scaffolds capture Granta-22 cells 2.4 times more than the PCL control does, although the two fiber scaffolds immobilize a comparable amount of anti-CD20. Taken together, results from the present study demonstrate that the CSS coating and CSS-mediated antibody immobilization offers an appealing strategy to functionalize electrospun synthetic polymer fibers and confer cell-specific functions on the fiber scaffolds, which can be mechanically robust but often lack biological functions.

[The clinical and pathologic study of embeded supernumerary teeth]

OBJECTIVE

To analyse the clinic and pathologic features of 100 embedded supernumerary teeth, to find out the rule of cystic change of supernumerary teeth and its relationship to malocclusion, and to present the methods of therapy.

METHODS

Analysis of clinical data, X-ray manifestation,comparison of the findings on operation and pathological changes demonstrated the correct diagnosis of supernumerary teeth.

RESULTS

On statistics and analysis,66% of the crowns of the supernumerary teeth were showed different sizes of circular photic shades,but only 35% were proved to be cystic change by biopsies.

CONCLUSION

This study showed that 35% had cystic change among 100 cases,so if the diagnosis can be made in these cases with indication of operation the extraction of the supernumerary teeth must be done as soon as possible.

Treatment of traumatic defect of the tibia with two exposed fractured ends--reduction and lengthening at the proximal metaphysics of tibia

From Jan. 1995 to June 1996, 6 cases of traumatic defect of the tibia were treated by remodeling and reduction of fractured ends and osteotomy and distraction at the proximal metaphysics of the tibia. In 6 patients, aged 19 to 54, with the limb-length discrepancy being at least 3 to 4.5 cm, the tibia was lengthened by 3 cm in 3 cases, 4 to 4.5 cm in 3 cases. The consolidation and maturation of the bone were accomplished within 3 to 6 months. The authors believe that this procedure is simple, less invasive and involves no bone-graft.

Clinical significance of childhood acute myeloid leukemias expressing lymphoid-associated antigens

The clinical significance of the expression of lymphoid-associated antigens in leukemic cells was studied in 66 children with newly diagnosed acute myeloid leukemia (AML). Among 66 AML cases, 17% were CD7-positive, 15% were CD19-positive, 8% were CD2-positive, and 5% were CD10-positive. In 23 (35%) of the 66 AML cases, at least one lymphoid-associated antigen was expressed in the leukemic cells. When the clinical features and laboratory findings were compared at diagnosis between the 23 Ly+ and the 43 Ly- AML cases, no statistically significant difference was found. The expression of CD34 was significantly more frequent in Ly+ AML cases (91%) than in Ly- AML cases (31%). Chromosomal analysis revealed t(8;21) in 6 of the 21 Ly+ AML cases examined. No other specific chromosome aberration was noted. The 3-year event-free survival rates of Ly+ AML cases and Ly- AML cases were 34% +/- 12% and 26% +/- 8%, respectively. There was no statistically significant difference between the two groups. Further studies are required to determine the prognostic significance of lymphoid-associated antigen expression.

[Results of the CCLSG high risk ALL 874 protocol in childhood acute lymphoblastic leukemia. Children's Cancer and Leukemia Study Group]

One hundred and eighty eight children with acute lymphoblastic leukemia (ALL) were treated in a Children's Cancer and Leukemia Study Group high-risk ALL 874 study from April, 1987 to September, 1991. These patients received a four-drug induction regimen followed by the early consolidation regimen, cranial irradiation at 6 months of remission and three years of continuation therapy with rotational administration of four drugs. The patients were randomized into two regimens. In regimen A, the consolidation chemotherapy consisted of the intermediate dose cytosine arabinoside (Ara-C), cyclophosphamide (CPM) plus 6MP, and in regimen B, it consisted of high-dose Ara-C plus CPM. Regimen A was given to 106 patients and 82 patients received regimen B. The complete remission induction rate for regimen A and B was 89.4% (93/104) and 98.7% (78/79), respectively. The 3-year event-free-survival (EFS) rate was 70.6% for regimen A, which was higher than the 56.7% for regimen B. The 3-year EFS rate was 44.4% for the 53 patients with an initial leukocyte count > or = 10 x 10(4)/microliters and 72.2% for 132 patients with a leukocyte count < 10 x 10(4)/microliter. We considered that Ara-C plus L-asp, added to the conventional high-risk ALL 811 protocol, improved the prognosis of the high risk ALL patients. However, further intensive chemotherapy was required for improvement of the outcome of the patients with hyperleukocytosis (> or = 10 x 10(4)/microliters).

[Analysis of cytoplasmic antigens in acute leukemia by flow cytometry]

The expression of cytoplasmic antigens in 77 cases of acute leukemia were analyzed by flow cytometry using the following monoclonal antibodies: CD3, CD22, anti-myeloperoxidase (MPO-7) and anti-mu-heavy chain. CD22 antigen was detected in the cytoplasm of all non-T-ALL patients excluding one not-tested patient. In two patients with unclassified ALL, surface CD22 antigen was not expressed but cytoplasmic CD22 antigen was strongly expressed. Three out of 9 patients with common ALL were cytoplasmic mu-heavy chain-positive, so these patients were diagnosed as Pre-B ALL. In four out of 8 patients with T-ALL, CD3 antigen was not expressed on the cell surface membrane. However all of T-ALL patients excluding one non-tested patient were cytoplasmic CD3-positive. The cytoplasmic expression of myeloperoxidase antigen was detected in twenty out of 21 patients with acute non-lymphoblastic leukemia (ANLL). One megakaryocytic leukemia patient was MPO-negative. In two ANLL patients, the percentage of MPO for conventional cytochemical staining was undetectable or low, but MPO antigens were positive (77% and 70%) for flow cytometric analysis. All of 46 non-T ALL patients were cytoplasmic MPO-negative, however 4 out of 10 T-ALL patients were cytoplasmic MPO-positive. The study proved that the analysis of cytoplasmic CD3, CD22, mu-chain and MPO antigens were very useful to define the cell lineage of leukemia and to classify ALL and ANLL. It is necessary to study further whether the expression of MPO in the cytoplasm of T-ALL was non-specific reaction or whether MPO precursors are expressed in the cytoplasm of T-ALL.

Cell-cycle-associated expressions of proliferating cell nuclear antigen and Ki-67 reactive antigen of bone marrow blast cells in childhood acute leukemia

To investigate the growth characteristics of human leukemia cells, the expression of proliferation-associated nuclear antigens was examined in relation to cell cycle phases in marrow blast cells obtained from 37 untreated children with acute leukemia. Ki-67 monoclonal antibody reactive antigen and proliferating cell nuclear antigen (PCNA) were measured by the simultaneous flow cytometric analysis of DNA and nuclear antigens. The percentage of PCNA-positive cells was always higher than that of Ki-67-positive cells in individual patients. The level of PCNA was greatly increased in G1 or early S phase, but was generally stable in S and G2 phases. Accordingly, most of the cells in the proliferative compartments (greater than 2C DNA) showed a high expression of PCNA. In contrast, expression of Ki-67 antigen varied greatly from patient to patient, and differed significantly in different subtypes of the disease. The level of Ki-67 antigen increased with the cell cycle progression, showing maximum expression in late S and G2 phases. However, in most of the patients, a distinct population of Ki-67-negative cells was found not only in G1 phase, but also in the proliferative compartments. These results appear to reflect differences in the proliferative activity of bone marrow blast cells in childhood acute leukemia.

Cell proliferation in childhood acute leukemia. Comparison of Ki-67 and proliferating cell nuclear antigen immunocytochemical and DNA flow cytometric analysis

The proliferative activity of bone marrow leukemia cells was determined by DNA flow cytometric (FCM) analysis and labeling index (LI) of Ki-67 monoclonal antibodies and proliferating cell nuclear antigen (PCNA) autoantibodies in 73 children with acute leukemia. LI of Ki-67 varied greatly from patient to patient (range, 0.4% to 42.2%; mean, 18.8%) and differed significantly between acute lymphoblastic leukemia (ALL) and acute nonlymphoblastic leukemia (ANLL). In ALL, the Ki-67 LI showed a positive correlation with the S-phase fraction (SPF) determined by DNA FCM analysis, whereas, in ANLL, there was a discrepancy between the Ki-67 LI and SPF. In contrast, LI of PCNA varied less among the patients (range, 57.2% to 100%; mean, 90.3%), and the value was always higher than that of the Ki-67 LI in individual patients. A significant relationship between PCNA LI and the percentage of blast cells was found in peripheral blood leukocytes from patients with leukemia. These results suggest that the Ki-67 LI reflects differences in the proliferative activity depending on the subtype of the disease and that the PCNA LI is useful as a marker of proliferating cells.

[Influences of new synthetic drug vesnarinone on circulatory and respiratory function of dogs]

The purpose of this study was to investigate the influences of vesnarinone, newly synthesized in the School of Pharmacy, West China University of Medical Sciences in 1985, on the circulatory and respiratory functions of dogs. Eight dogs were anesthetized with 3% sodium pentobarbital. Vesnarinone (2 mg/kg), dimethyl sulphoxide (the solvent which was needed to prepare solution of OPC-8212), and 0.9% NaCl (normal control) was given separately according to the arrangement of Latin square. The ECG, blood flow, blood pressure and respiration were measured and recorded for 1-15 minutes. Vesnarinone increased the blood flow in the common carotid artery with no significant changes in blood pressure, heart rate, or respiration. These results suggest that OPC-8212 has positive inotropic effect but no effect on the heart rate in anesthetized dogs.

[Research and application of SUPER-1 intellectural instrument used in physiology laboratory]

Research work for making a biomedical signal processing instrument based on the APPLE-II computer is reported in this paper. According to the theory of the computer, two interface boards were designed as the hardware of the instrument. The memorizing waveform program was designed as the main program in the software system. Through a functional extended program, also called software inter face, more than ten programs especially for physiology can be easily linked to the main program. with the combination of both the software and hard ware several parameters of the instrument, such as sampling speed, gain of the amplifier, etc. can be controlled by a closed loop. This instrument is available in the physiology laboratory to replace oscilloscope, recorder, stimulator simultaneously. The functions of the instrument are stronger than those of the conventional instruments.

[Effect of a new positive inotropic agent (OPC-8212) on intracellular potential of isolated canine ventricular papillary muscle]

This study adopted intracellular microelectrode technic to observe the effect of OPC-8212 (Vesnarinone) on intracellular potential of isolated canine ventricular papillary muscle. The record and data processing were completed by computerized intellective instrument designed by ourselves. The results of intracellular record in 14 canine ventricular papillary muscle showed no significant change in the resting potential (RP), amplitude of action potential (APA) and maximum depolarize velocity of 0 phase (Vmax). But significantly increased whole duration of action potential (APT). The duration of repolarization to 1/3 (APD 1/3) and to 2/3 (APD 2/3) significantly increased too. The plateau phase raised. These results suggest that K+ permeability at resting myocardiac cell membrane may have not been effected by OPC-8212. Activation of the fast sodium channel may have not been effected too. The results of our studies also suggest that inward flow of Ca2+ increased. The delayed outward K+ (Ik) and the inward, rectifying K+ current (Ik1) possible decreased. Thus, the OPC-8212 might become a nonglucoside and noncatecholamine new positive inotropic drug.