Marine sulfated glycans inhibit the interaction of heparin with S-protein of SARS-CoV-2 Omicron XBB variant

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide COVID-19 pandemic, leading to 6.8 million deaths. Numerous variants have emerged since its outbreak, resulting in its significantly enhanced ability to spread among humans. As with many other viruses, SARS‑CoV‑2 utilizes heparan sulfate (HS) glycosaminoglycan (GAG) on the surface of host cells to facilitate viral attachment and initiate cellular entry through the ACE2 receptor. Therefore, interfering with virion-HS interactions represents a promising target to develop broad-spectrum antiviral therapeutics. Sulfated glycans derived from marine organisms have been proven to be exceptional reservoirs of naturally existing HS mimetics, which exhibit remarkable therapeutic properties encompassing antiviral/microbial, antitumor, anticoagulant, and anti-inflammatory activities. In the current study, the interactions between the receptor-binding domain (RBD) of S-protein of SARS-CoV-2 (both WT and XBB.1.5 variants) and heparin were applied to assess the inhibitory activity of 10 marine-sourced glycans including three sulfated fucans, three fucosylated chondroitin sulfates and two fucoidans derived from sea cucumbers, sea urchin and seaweed Saccharina japonica, respectively. The inhibitory activity of these marine derived sulfated glycans on the interactions between RBD of S-protein and heparin was evaluated using Surface Plasmon Resonance (SPR). The RBDs of S-proteins from both Omicrion XBB.1.5 and wild-type (WT) were found to bind to heparin, which is a highly sulfated form of HS. All the tested marine-sourced sulfated glycans exhibited strong inhibition of WT and XBB.1.5 S-protein binding to heparin. We believe the study on the molecular interactions between S-proteins and host cell glycosaminoglycans provides valuable insight for the development of marine-sourced, glycan-based inhibitors as potential anti-SARS-CoV-2 agents.

Nuclear magnetic resonance-based structural elucidation of novel marine glycans and derived oligosaccharides

Marine glycans of defined structures are unique representatives among all kinds of structurally complex glycans endowed with important biological actions. Besides their unique biological properties, these marine sugars also enable advanced structure-activity relationship (SAR) studies given their distinct and defined structures. However, the natural high molecular weights (MWs) of these marine polysaccharides, sometimes even bigger than 100 kDa, pose a problem in many biophysical and analytical studies. Hence, the preparation of low MW oligosaccharides becomes a strategy to overcome the problem. Regardless of the polymeric or oligomeric lengths of these molecules, structural elucidation is mandatory for SAR studies. For this, nuclear magnetic resonance (NMR) spectroscopy plays a pivotal role. Here, we revisit the NMR-based structural elucidation of a series of marine sulfated poly/oligosaccharides discovered in our laboratory within the last 2 years. This set of structures includes the α-glucan extracted from the bivalve Marcia hiantina; the two sulfated galactans extracted from the red alga Botryocladia occidentalis; the fucosylated chondroitin sulfate isolated from the sea cucumber Pentacta pygmaea; the oligosaccharides produced from the fucosylated chondroitin sulfates from this sea cucumber species and from another species, Holothuria floridana; and the sulfated fucan from this later species. Specific 1H and 13C chemical shifts, generated by various 1D and 2D homonuclear and heteronuclear NMR spectra, are exploited as the primary source of information in the structural elucidation of these marine glycans.

Academic clinician frontline-worker wellbeing and resilience during the COVID-19 pandemic experience: Were there gender differences?

Prior research suggests COVID-19 has amplified stress on Academic Clinician Frontline-Workers (ACFW). The aim of this paper is: (1) to better understand the experiences of ACFW during the COVID-19 pandemic including their mental-emotional wellbeing, academic productivity, clinical experiences, and (2) to examine any gender differences. A cross-sectional survey was administered to University of Minnesota/M Health Fairview systems' faculty February-June 2021. Of the 291 respondents, 156 were clinicians, with 91 (58 %) identifying as Frontline-Workers (ACFW). Faculty wellbeing was assessed using validated measures in addition to measures of productivity and sociodemographics. For example, ACFW reported a higher Work-Family Conflict (WFC) scores compared to non-ACFW (26.5 vs. 24.1, p = 0.057) but did not report higher Family-Work Conflict (FWC) scores (17.7 vs. 16.3, p = 0.302). Gender sub-analyses, revealed that women ACFW compared to men ACFW reported higher WFC scores (27.7 vs. 24.1, p = 0.021) and FWC (19.3 vs. 14.3, p = 0.004). Academically, ACFW reported submitting fewer grants and anticipated delays in promotion and tenure due to the COVID-19 (p = 0.035). Results suggest COVID-19 has exacerbated ACFW stress and gender inequities. Reports of anticipated delay in promotion for ACFW may pose a challenge for the long-term academic success of ACFW, especially women ACFW. In addition, women may experience higher FWC and WFC as compared to men. Schools of academic medicine should consider re-evaluating promotion/tenure processes and creating resources to support women ACFW as well as ACFW caregivers.

The Sea Cucumber Thyonella gemmata Contains a Low Anticoagulant Sulfated Fucan with High Anti-SARS-CoV-2 Actions against Wild-Type and Delta Variants

In this work, we isolated two new sulfated glycans from the body wall of the sea cucumber Thyonella gemmata: one fucosylated chondroitin sulfate (TgFucCS) (17.5 ± 3.5% kDa) and one sulfated fucan (TgSF) (383.3 ± 2.1% kDa). NMR results showed the TgFucCS backbone composed of [→3)-β-N-acetylgalactosamine-(1→4)-β-glucuronic acid-(1→] with 70% 4-sulfated and 30% 4,6-disulfated GalNAc units and one-third of the GlcA units decorated at the C3 position with branching α-fucose (Fuc) units either 4-sulfated (65%) or 2,4-disulfated (35%) and the TgSF structure composed of a tetrasaccharide repeating unit of [→3)-α-Fuc2,4S-(1→2)-α-Fuc4S-(1→3)-α-Fuc2S-(1→3)-α-Fuc2S-(1→]n. Inhibitory properties of TgFucCS and TgSF were investigated using SARS-CoV-2 pseudovirus coated with S-proteins of the wild-type (Wuhan-Hu-1) or the delta (B.1.617.2) strains and in four different anticoagulant assays, comparatively with unfractionated heparin. Molecular binding to coagulation (co)-factors and S-proteins was investigated by competitive surface plasmon resonance spectroscopy. Among the two sulfated glycans tested, TgSF showed significant anti-SARS-CoV-2 activity against both strains together with low anticoagulant properties, indicating a good candidate for future studies in drug development.

SPR Sensor-Based Analysis of the Inhibition of Marine Sulfated Glycans on Interactions between Monkeypox Virus Proteins and Glycosaminoglycans

Sulfated glycans from marine organisms are excellent sources of naturally occurring glycosaminoglycan (GAG) mimetics that demonstrate therapeutic activities, such as antiviral/microbial infection, anticoagulant, anticancer, and anti-inflammation activities. Many viruses use the heparan sulfate (HS) GAG on the surface of host cells as co-receptors for attachment and initiating cell entry. Therefore, virion-HS interactions have been targeted to develop broad-spectrum antiviral therapeutics. Here we report the potential anti-monkeypox virus (MPXV) activities of eight defined marine sulfated glycans, three fucosylated chondroitin sulfates, and three sulfated fucans extracted from the sea cucumber species Isostichopus badionotus, Holothuria floridana, and Pentacta pygmaea, and the sea urchin Lytechinus variegatus, as well as two chemically desulfated derivatives. The inhibitions of these marine sulfated glycans on MPXV A29 and A35 protein-heparin interactions were evaluated using surface plasmon resonance (SPR). These results demonstrated that the viral surface proteins of MPXV A29 and A35 bound to heparin, which is a highly sulfated HS, and sulfated glycans from sea cucumbers showed strong inhibition of MPXV A29 and A35 interactions. The study of molecular interactions between viral proteins and host cell GAGs is important in developing therapeutics for the prevention and treatment of MPXV.

Inhibition of Cytomegalovirus by Pentacta pygmaea Fucosylated Chondroitin Sulfate Depends on Its Molecular Weight

Many viruses attach to host cells by first interacting with cell surface proteoglycans containing heparan sulfate (HS) glycosaminoglycan chains and then by engaging with specific receptor, resulting in virus entry. In this project, HS–virus interactions were targeted by a new fucosylated chondroitin sulfate from the sea cucumber Pentacta pygmaea (PpFucCS) in order to block human cytomegalovirus (HCMV) entry into cells. Human foreskin fibroblasts were infected with HCMV in the presence of PpFucCS and its low molecular weight (LMW) fractions and the virus yield at five days post-infection was assessed. The virus attachment and entry into the cells were visualized by labeling the purified virus particles with a self-quenching fluorophore octadecyl rhodamine B (R18). The native PpFucCS exhibited potent inhibitory activity against HCMV specifically blocking virus entry into the cell and the inhibitory activities of the LMW PpFucCS derivatives were proportional to their chain lengths. PpFucCS and the derived oligosaccharides did not exhibit any significant cytotoxicity; moreover, they protected the infected cells from virus-induced lytic cell death. In conclusion, PpFucCS inhibits the entry of HCMV into cells and the high MW of this carbohydrate is a key structural element to achieve the maximal anti-viral effect. This new marine sulfated glycan can be developed into a potential prophylactic and therapeutic antiviral agent against HCMV infection.

Excitatory cholinergic responses in mouse primary bronchial smooth muscle require both Ca2+ entry via l-type Ca2+ channels and store operated Ca2+ entry via Orai channels

Malfunctions in airway smooth muscle Ca²⁺-signalling leads to airway hyperresponsiveness in asthma and chronic obstructive pulmonary disease. Ca²⁺-release from intracellular stores is important in mediating agonist-induced contractions, but the role of influx via l-type Ca²⁺ channels is controversial. We re-examined roles of the sarcoplasmic reticulum Ca²⁺ store, refilling of this store via store-operated Ca²⁺ entry (SOCE) and l-type Ca²⁺ channel pathways on carbachol (CCh, 0.1-10 µM)-induced contractions of mouse bronchial rings and intracellular Ca²⁺ signals of mouse bronchial myocytes. In tension experiments, the ryanodine receptor (RyR) blocker dantrolene (100 µM) reduced CCh-responses at all concentrations, with greater effects on sustained rather than initial components of contraction. 2-Aminoethoxydiphenyl borate (2-APB, 100 μM), in the presence of dantrolene, abolished CCh-responses, suggesting the sarcoplasmic reticulum Ca²⁺ store is essential for contraction. The SOCE blocker GSK-7975A (10 µM) reduced CCh-contractions, with greater effects at higher (e.g. 3 and 10 µM) CCh concentrations. Nifedipine (1 µM), abolished remaining contractions in GSK-7975A (10 µM). A similar pattern was observed on intracellular Ca²⁺-responses to 0.3 µM CCh, where GSK-7975A (10 µM) substantially reduced Ca²⁺ transients induced by CCh, and nifedipine (1 µM) abolished remaining responses. When nifedipine (1 µM) was applied alone it had less effect, reducing tension responses at all CCh concentrations by 25% - 50%, with greater effects at lower (e.g. 0.1 and 0.3 µM) CCh concentrations. When nifedipine (1 µM) was examined on the intracellular Ca²⁺-response to 0.3 µM CCh, it only modestly reduced Ca²⁺ signals, while GSK-7975A (10 µM) abolished remaining responses. In conclusion, Ca²⁺-influx from both SOCE and l-type Ca²⁺ channels contribute to excitatory cholinergic responses in mouse bronchi. The contribution of l-type Ca²⁺ channels was especially pronounced at lower doses of CCh, or when SOCE was blocked. This suggests l-type Ca²⁺ channels might be a potential target for bronchoconstriction under certain circumstances.

Antiviral activity of marine sulfated glycans against pathogenic human coronaviruses

Great interest exists towards the discovery and development of broad-spectrum antivirals. This occurs due to the frequent emergence of new viruses which can also eventually lead to pandemics. A reasonable and efficient strategy to develop new broad-spectrum antivirals relies on targeting a common molecular player of various viruses. Heparan sulfate is a sulfated glycosaminoglycan present on the surface of cells which plays a key role as co-receptor in many virus infections. In previous work, marine sulfated glycans (MSGs) were identified as having antiviral activities. Their mechanism of action relies primarily on competitive inhibition of virion binding to heparan sulfate, preventing virus attachment to the cell surface prior to entry. In the current work we used pseudotyped lentivirus particles to investigate in a comparative fashion the inhibitory properties of five structurally defined MSGs against SARS-CoV-1, SARS-CoV-2, MERS-CoV, and influenza A virus (IAV). MSGs include the disaccharide-repeating sulfated galactan from the red alga Botryocladia occidentalis, the tetrasaccharide-repeating sulfated fucans from the sea urchin Lytechinus variegatus and from the sea cucumber Isostichopus badionotus, and the two marine fucosylated chondroitin sulfates from the sea cucumbers I. badionotus and Pentacta pygmaea. Results indicate specificity of action against SARS-CoV-1 and SARS-CoV-2. Curiously, the MSGs showed decreased inhibitory potencies against MERS-CoV and negligible action against IAV. Among the five MSGs, the two sulfated fucans here studied deserve further attention since they have the lowest anticoagulant effects but still present potent and selective antiviral properties.

Anti-SARS-CoV-2 and anticoagulant properties of Pentacta pygmaea fucosylated chondroitin sulfate depend on high molecular weight structures

Fucosylated chondroitin sulfate (FucCS) is a unique marine glycosaminoglycan that exhibits diverse biological functions, including antiviral and anticoagulant activity. In previous work, the FucCS derived from Pentacta pygmaea (PpFucCS) showed moderate anticoagulant effect but high inhibitory activity against the Wuhan strain of severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this study, we perform free-radical depolymerization of PpFucCS by the copper-based Fenton method to generate low molecular weight (MW) oligosaccharides. PpFucCS oligosaccharides were structurally analyzed by 1H nuclear magnetic resonance spectroscopy and were used to conduct structure-activity relationship studies regarding their effects against SARS-CoV-2 and clotting. Anticoagulant properties were measured by activated partial thromboplastin time, protease (factors Xa and IIa) inhibition by serine protease inhibitors (antithrombin [AT] and heparin cofactor II [HCII]), and competitive surface plasmon resonance (SPR) assay using AT, HCII, and IIa. Anti-SARS-CoV-2 properties were measured by the concentration-response inhibitory curves of HEK-293T-human angiotensin-converting enzyme-2 cells infected with a baculovirus pseudotyped SARS-CoV-2 Delta variant spike (S)-protein and competitive SPR assays using multiple S-proteins (Wuhan, N501Y [Alpha], K417T/E484K/N501Y [Gamma], L542R [Delta], and Omicron [BA.2 subvariant]). Cytotoxicity of native PpFucCS and oligosaccharides was also assessed. The PpFucCS-derived oligosaccharide fraction of the highest MW showed great anti-SARS-CoV-2 Delta activity and reduced anticoagulant properties. Results have indicated no cytotoxicity and MW dependency on both anti-SARS-CoV-2 and anticoagulant effects of PpFucCS, as both actions were reduced accordingly to the MW decrease of PpFucCS. Our results demonstrate that the high-MW structures of PpFucCS is a key structural element to achieve the maximal anti-SARS-CoV-2 and anticoagulant effects.

Structural requirements of Holothuria floridana fucosylated chondroitin sulfate oligosaccharides in anti-SARS-CoV-2 and anticoagulant activities

Fucosylated chondroitin sulfate (FucCS) is a unique glycosaminoglycan found primarily in sea cucumbers. This marine sulfated glycan is composed of a chondroitin sulfate backbone decorated with fucosyl branches attached to the glucuronic acid. FucCS exhibits potential biological actions including inhibition of blood clotting and severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. These biological effects have been attributed to certain structural features, including molecular weight (MW), and/or those related to fucosylation, such as degrees of fucosyl branches, sulfation patterns and contents. In a previous work, we were able to generate oligosaccharides of the FucCS from Pentacta pygmaea (PpFucCS) with reduced anticoagulant effect but still retaining significant anti-SARS-CoV-2 activity against the delta strain. In this work, we extended our study to the FucCS extracted from the species Holothuria floridana (HfFucCS). The oligosaccharides were prepared by free-radical depolymerization of the HfFucCS via copper-based Fenton reaction. One-dimensional 1H nuclear magnetic resonance spectra were employed in structural analysis. Activated partial thromboplastin time and assays using protease (factors Xa and IIa) and serine protease inhibitors (antithrombin, and heparin cofactor II) in the presence of the sulfated carbohydrates were used to monitor anticoagulation. Anti-SARS-CoV-2 effects were measured using the concentration-response inhibitory curves of HEK-293T-human angiotensin-converting enzyme-2 cells infected with a baculovirus pseudotyped SARS-CoV-2 wild-type and delta variant spike (S)-proteins. Furthermore, the cytotoxicity of native HfFucCS and its oligosaccharides was also assessed. Like for PpFucCS, we were able to generate a HfFucCS oligosaccharide fraction devoid of high anticoagulant effect but still retaining considerable anti-SARS-CoV-2 actions against both variants. However, compared to the oligosaccharide fraction derived from PpFucCS, the average MW of the shortest active HfFucCS oligosaccharide fraction was significantly lower. This finding suggests that the specific structural feature in HfFucCS, the branching 3,4-di-sulfated fucoses together with the backbone 4,6-di-sulfated N-acetylgalactosamines, is relevant for the anti-SARS-CoV-2 activity of FucCS molecules.

Inhibition of SARS-CoV-2 wild-type (Wuhan-Hu-1) and Delta (B.1.617.2) strains by marine sulfated glycans

The Coronavirus disease pandemic has steered the global therapeutic research efforts toward the discovery of potential anti-severe acute respiratory syndrome coronavirus (SARS-CoV-2) molecules. The role of the viral spike glycoprotein (S-protein) has been clearly established in SARS-CoV-2 infection through its capacity to bind to the host cell surface heparan sulfate proteoglycan (HSPG) and angiotensin-converting enzyme-2. The antiviral strategies targeting these 2 virus receptors are currently under intense investigation. However, the rapid evolution of the SARS-CoV-2 genome has resulted in numerous mutations in the S-protein posing a significant challenge for the design of S-protein-targeted inhibitors. As an example, the 2 key mutations in the S-protein receptor-binding domain (RBD), L452R, and T478K in the SARS-CoV-2 Delta variant (B.1.617.2) confer tighter binding to the host epithelial cells. Marine sulfated glycans (MSGs) demonstrate excellent inhibitory activity against SARS-CoV-2 via competitive disruption of the S-protein RBD-HSPG interactions and thus have the potential to be developed into effective prophylactic and therapeutic molecules. In this study, 7 different MSGs were evaluated for their anti-SARS-CoV-2 activity in a virus entry assay utilizing a SARS-CoV-2 pseudovirus coated with S-protein of the wild-type (Wuhan-Hu-1) or the Delta (B.1.617.2) strain. Although all tested MSGs showed strong inhibitory activity against both strains, no correlations between MSG structural features and virus inhibition could be drawn. Nevertheless, the current study provides evidence for the maintenance of inhibitory activity of MSGs against evolving SARS-CoV-2 strains.

987 TACKLING OVERPRESCRIBING; WHAT ABOUT THE HABITUAL OFFENDER, PPI?

Introduction

Overprescribing is a serious problem in health systems internationally and can lead to preventable hospital assessments and admissions, even premature deaths1. Proton pump inhibitors (PPIs) are commonly prescribed in older people. They are associated with risk of C difficile infection, hypomagnesemia, osteoporosis, hypergastrinaemia, and are considered falls risk increasing drugs (FRID). Unfortunately, there isn’t a guideline which unifies the various indications of PPIs.

Method

303 discharges were screened from 2 acute geriatric wards between 01/10/2020 and 31/12/2020. After exclusions (34 deaths, 5 readmissions), 264 notes were reviewed. Those with a PPI mentioned on their discharge summaries were audited against both NICE dyspepsia guidelines and our hospital trust guidelines (PPI usage in those on co-medications), assessing whether long term use was advocated. Additional information was obtained from our hospital systems including digital health records.

Results

153/264(58%) patients had PPIs listed on their discharge summaries. Of those using PPIs, 146 (95%) had polypharmacy and 140(92%) had a CFS ≥5. More PPIs were commenced (18) than discontinued (16). Against NICE dyspepsia guidelines, 46/153(30%) patients did not require long term PPI treatment. 81/153 (53%) patients had a PPI prescribed due to anticoagulation, however, 37/81 (46%) did not fulfil our trust criteria for co-prescription.

Conclusion

PPI usage is prevalent in older people and often continued without a valid indication which could result in preventable harm in an already vulnerable cohort. There is a need to actively deprescribe PPIs within all healthcare settings. Our findings have been widely shared with our departmental colleagues and other relevant specialties and a guideline on long term use of PPIs in older people (>65) has been developed. Going forward, we plan to re-audit against this new guideline in 6 months to assess improvement.

References 1. Good for you, good for us, good for everybody. Published 22/9/21.

1048 REDUCING RISK FROM WARFARIN- A COMPLETED AUDIT CYCLE ON NICE COMPLIANCE WITH WARFARIN FOR NVAF IN HOSPITALISED OLDER PEOPLE

Introduction

Traditionally Warfarin has been mainly used for stroke thromboprophylaxis in patients with atrial fibrillation but direct oral anticoagulant (DOAC) are increasingly being used as they have improved safety profiles with comparable efficacy. Recent data from National Reporting and Learning System (NRLS) have discovered safety incidents related to anticoagulation, predominantly Warfarin, contributing in excess of 10% of all medication errors. National institute for clinical excellence (NICE) recommends reassessing anticoagulation choice for patients on Warfarin with poor anticoagulation control, indicated by any of the following: 1 > 2 INR values <1.5 or > 5 or 1 INR value >8, within the past 6 months 2 > Time in therapeutic range (TTR) <65% Intervention An initial retrospective audit on 50 patients on Warfarin for NVAF performed between June—September 18 showed poor compliance with NICE. We reviewed the previous 6 months INR values and recorded any significant deviations outside of the therapeutic range as per NICE. TTR over the last 6 months was calculated using the Rosendaal method. Following departmental audit presentation, a reaudit was carried out between Jan-Aug 2019 to assess improvement.

Results

Median age was 87.5 compared to 83 in the first audit. Warfarin was correctly continued in 7/38(18%) in the 1st audit which improved to 9/28 (32%) in the second. Number of patients discharged on warfarin with unstable INRs decreased significantly from 26/32 (81%) patients in the 1st audit to 10/24 (42%) in the 2nd.

Discussion

Our reaudit shows significant reduction in continuation of warfarin on discharge in patients with unstable INRs (p = 0.0043 Fisher exact test). Although, there is a trend towards improvement with NICE compliance; in general, the compliance with NICE remains poor. We suggest geriatricians to proactively review the appropriateness of warfarin prescription and to consider a DOAC in preference to Warfarin in all elderly patients.

Structural and kinetic analyses of holothurian sulfated glycans suggest potential treatment for SARS-CoV-2 infection

Certain sulfated glycans, including those from marine sources, can show potential effects against SARS-CoV-2. Here, a new fucosylated chondroitin sulfate (FucCS) from the sea cucumber Pentacta pygmaea (PpFucCS) (MW ∼10-60 kDa) was isolated and structurally characterized by NMR. PpFucCS is composed of {→3)-β-GalNAcX-(1→4)-β-GlcA-[(3→1)Y]-(1→}, where X = 4S (80%), 6S (10%) or nonsulfated (10%), Y = α-Fuc2,4S (40%), α-Fuc2,4S-(1→4)-α-Fuc (30%), or α-Fuc4S (30%), and S = SO3-. The anti-SARS-CoV-2 activity of PpFucCS and those of the FucCS and sulfated fucan isolated from Isostichopus badionotus (IbFucCS and IbSF) were compared with that of heparin. IC50 values demonstrated the activity of the three holothurian sulfated glycans to be ∼12 times more efficient than heparin, with no cytotoxic effects. The dissociation constant (KD) values obtained by surface plasmon resonance of the wildtype SARS-CoV-2 spike (S)-protein receptor-binding domain (RBD) and N501Y mutant RBD in interactions with the heparin-immobilized sensor chip were 94 and 1.8 × 103 nM, respectively. Competitive surface plasmon resonance inhibition analysis of PpFucCS, IbFucCS, and IbSF against heparin binding to wildtype S-protein showed IC50 values (in the nanomolar range) 6, 25, and 6 times more efficient than heparin, respectively. Data from computational simulations suggest an influence of the sulfation patterns of the Fuc units on hydrogen bonding with GlcA and that conformational change of some of the oligosaccharide structures occurs upon S-protein RBD binding. Compared with heparin, negligible anticoagulant action was observed for IbSF. Our results suggest that IbSF may represent a promising molecule for future investigations against SARS-CoV-2.

Safety and Pharmacokinetics of Intranasally Administered Heparin.. [PMID: 35194614 PMCID: PMC8863150 DOI: 10.1101/2021.07.05.21259936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Purpose

Intranasally administered unfractionated heparin (UFH) and other sulfated polysaccharides are potential prophylactics for COVID-19. The purpose of this research was to measure the safety and pharmacokinetics of clearance of intranasally administered UFH solution from the nasal cavity.

Methods

Double-blinded daily intranasal dosing in C57Bl6 mice with four doses (60 ng to 60 μg) of UFH was carried out for fourteen consecutive days, with both blood coagulation measurements and subject adverse event monitoring. The pharmacokinetics of fluorescent-labeled UFH clearance from the nasal cavity were measured in mice by in vivo imaging. Intranasal UFH at 2000 U/day solution with nasal spray device was tested for safety in a small number of healthy human subjects.

Results

UFH showed no evidence of toxicity in mice at any dose measured. No significant changes were observed in activated partial thromboplastin time (aPTT), platelet count, or frequency of minor irritant events over vehicle-only control. Human subjects showed no significant changes in aPTT time, international normalized ratio (INR), or platelet count over baseline measurements. No serious adverse events were observed. In vivo imaging in a mouse model showed a single phase clearance of UFH from the nasal cavity. After 12 hours, 3.2% of the administered UFH remained in the nasal cavity, decaying to background levels by 48 hours.

Conclusions

UFH showed no toxic effects for extended daily intranasal dosing in mice as well as humans. The clearance kinetics of intranasal heparin solution from the nasal cavity indicates potentially protective levels for up to 12 hours after dosing.

Antiviral activities of four marine sulfated glycans against adenovirus and human cytomegalovirus

Broad-spectrum antivirals are more needed than ever to provide treatment options for novel emerging viruses and for viruses that lack therapeutic options or have developed resistance. A large number of viruses rely on charge-dependent non-specific interactions with heparan sulfate (HS), a highly sulfated glycosaminoglycan (GAG), for attachment to cell surfaces to initiate cell entry. As such, inhibitors targeting virion-HS interactions have potential to have broad-spectrum antiviral activity. Previous research has explored organic and inorganic small molecules, peptides, and GAG mimetics to disrupt virion-HS interactions. Here we report antiviral activities against both enveloped (the herpesvirus human cytomegalovirus) and non-enveloped (adenovirus) DNA viruses for four defined marine sulfated glycans: a sulfated galactan from the red alga Botryocladia occidentalis; a sulfated fucan from the sea urchin Lytechinus variegatus, and a sulfated fucan and a fucosylated chondroitin sulfate from the sea cucumber Isostichopus badionotus. As evidenced by gene expression, time of addition, and treatment/removal assays, all four novel glycans inhibited viral attachment and entry, most likely through interactions with virions. The sulfated fucans, which both lack anticoagulant activity, had similar antiviral profiles, suggesting that their activities are not only due to sulfation content or negative charge density but also due to other physicochemical factors such as the potential conformational shapes of these carbohydrates in solution and upon interaction with virion proteins. The structural and chemical properties of these marine sulfated glycans provide unique opportunities to explore relationships between glycan structure and their antiviral activities.

Marine Antithrombotics

Thrombosis remains a prime reason of mortality worldwide. With the available antithrombotic drugs, bleeding remains the major downside of current treatments. This raises a clinical concern for all patients undergoing antithrombotic therapy. Novel antithrombotics from marine sources offer a promising therapeutic alternative to this pathology. However, for any potential new molecule to be introduced as a real alternative to existing drugs, the exhibition of comparable anticoagulant potential with minimal off-target effects must be achieved. The relevance of marine antithrombotics, particularly sulfated polysaccharides, is largely due to their unique mechanisms of action and lack of bleeding. There have been many investigations in the field and, in recent years, results have confirmed the role of potential marine molecules as alternative antithrombotics. Nonetheless, further clinical studies are required. This review covers the core of the data available so far regarding the science of marine molecules with potential medical applications to treat thrombosis. After a general discussion about the major biochemical steps involved in this pathology, we discuss the key structural and biomedical aspects of marine molecules of both low and high molecular weight endowed with antithrombotic/anticoagulant properties.

Design of therapeutically improved analogue of the antimicrobial peptide, indolicidin, using a glycosylation strategy

Indolicidin is a member of cathelicidin family which displays broad spectrum antimicrobial activity. Severe toxicity and aggregation propensity associated with indolicidin pose a huge limitation to its probable therapeutic application. We are reporting the use of glycosylation strategy to design an analogue of indolicidin and subsequently explore structural and functional effects of sugar on it. Our study led to the design of a potent antibacterial glycosylated peptide, [βGlc-T9,K7]indolicidin, which showed decreased toxicity against erythrocytes and macrophage cells and thus a higher therapeutic selectivity. The incorporation of sugar also increased the solubility of the peptide. The mode of bacterial killing, functional stability, LPS binding, and cytokine inhibitory potential of the peptide, however, seemed unaffected upon glycosylation. Absence of significant changes in structure upon glycosylation accounts for the possibly retained functions and mode of action of the peptide. Our report thus presents the designing of an indolicidin analogue with improved therapeutic potential by substituting aromatic amino acid with glycosylated amino acid as a promising strategy for the first time.

Purification, characterization and retting of Crotolaria juncea fibres by an alkaline pectin lyase from Fusarium oxysporum MTCC 1755

Using solid-state fermentation, production of an industrially important pectin lyase from a fungal strain Fusarium oxysporum MTCC 1755 was attempted, which was further subjected to purification and characterization. The enzyme was purified by three steps, namely ammonium sulfate fractionation, cation-exchange chromatography on CM cellulose followed by gel filtration chromatography using Sephadex G-100 column. A 16-fold purification with 31.2% yield and 3.2 U/mg specific activity was achieved. The optimum pH of the purified enzyme was 9.0 and stability ranged from pH 5.0-7.0 for 24 h. Optimum temperature of purified enzyme was found to be 40 °C while temperature stability ranged from 10 to 50 °C for 30 min. The K _m and k _cat of the enzyme was 1.75 mg/ml and 83.3 s^-1, respectively. The purified enzyme was found to be highly stimulated by Ca²⁺ ions while sugars like mannitol and sorbitol, and salts like NaCl and CaCl₂ enhanced the thermostability. The purified pectin lyase was found suitable for retting of Crotolaria juncea fiber.

Assessment of serum apolipoprotein B and apolipoprotein A-1 and their ratio in healthy full term small for gestational age newborns

BACKGROUND

Programmed changes in growth restricted fetuses can increase the risk of adulthood diseases due to elevated serum cholesterol and apolipoprotein-B (Apo-B) concentrations. Increasing evidence demonstrated the role of apoB/apoA-I ratio as a strong risk factor for cardiovascular diseases.

OBJECTIVE

To determine the concentration of cord blood lipoproteins and apolipoproteins as well as their correlation with birth weight.

METHODS

This cross-sectional study was conducted in a teaching institution in central India. Healthy full-term newborns, born out of normal vaginal deliveries, were recruited. Cases include term small for gestational age (SGA) babies while term appropriate for gestational age (AGA) babies were taken as controls. Their umbilical venous blood was collected and sent for biochemical analysis.

RESULTS

Out of 126 healthy newborns, 66 were cases and 60 were controls. Mean values of serum triglyceride (141.56±69.67 mg/dl vs. 113.67±33.38 mg/dl; p < 0.006; 95% CI = 8.31 to 47.46) and serum apo-B/apo-A-1 ratio (0.67±0.28 vs. 0.55±0.20; p < 0.007; 95% CI = 0.033 to 0.206) were significantly high and that of serum high density cholesterol (35.84±10.42 mg/dl vs. 40.73±11.70 mg/dl; p < 0.014; 95% CI = -8.79 to -0.98) and Apo-A1 [87.59±12.44 mg/dl vs. 101.87±35.07 mg/dl; p = 0.002; 95% CI = -23.39 to -5.16) were significantly low in SGA newborns. Serum cholesterol, very low-density cholesterol rlow-density cholesterol rand Apo-B did not show any significant difference. Among SGA newborns significant negative correlation was seen between birth weight and apo-B/apo-A1 and serum triglyceride, while birth weight and serum apo-A1 level showed significant positive correlation. There was no statistically significant correlation between birth weight and other parameters.

CONCLUSION

These findings further support the association of prenatal factors with lipid profile rand can serve as starting point for studying lipid transport system changes during early life in Indian population.

Remote sensing of bacterial response to degrading phytoplankton in the Arabian Sea

A remote sensing technique has been developed to detect physiological condition of phytoplankton using in situ and moderate imaging spectroradiometer (MODIS)-Aqua data. The recurring massive mixed algal bloom of diatom and Noctiluca scintillans in the Northern Arabian Sea during winter-spring was used as test bed to study formation, growth and degradation of phytoplankton. The ratio of chlorophyll (chl) to particulate organic carbon (POC) was considered as an indicator of phytoplankton physiological condition and used for the approach development. Algal blooms represent the areas of new production, and therefore, knowledge of their degradation is important to the study microbial loop and export carbon flux. Relation of chl/POC ratio with bacterial abundance revealed Gaussian distribution. Bacteria were strongly correlated with POC, and hence, the latter which is available from satellite data could be used as a proxy for remote assessment of bacteria. Thresholds for active and degrading phytoplankton were determined using the ratio computed from the satellite data. The criteria were implemented on MODIS data to generate an image representing distribution of degrading algal bloom. Bacteria abundance data from two validation cruises during dinoflagellate and cyanobacteria bloom confirmed well match up of phytoplankton degradation information from the satellite. Comparison of environmental parameters during decay phase of dinoflagellate (N. scintillans bloom (winter) and Trichodesmium bloom (summer) revealed that degradation after active Trichodesmium bloom was more severe as compared to the N. scintillans. The present study also highlights the prediction capability of phytoplankton degradation using a time series of satellite retrieved chlorophyll/POC images.

MODIS-Aqua detects Noctiluca scintillans and hotspots in the central Arabian Sea

Northern Arabian Sea is considered as an ecologically sensitive area as it experiences a massive upwelling and long-lasting algal bloom, Noctiluca scintillans (green tide) during summer and spring-winter, respectively. Diatom bloom is also found to be co-located with N. scintillans and both have an impact on ecology of the basin. In-house technique of detecting species of these blooms from Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua data was used to generate a time-series of images revealing their spatial distribution. A study of spatial-temporal variability of these blooms using satellite data expressed a cyclic pattern of their spread over a period of 13 years. An average distribution of the blooms for January-March period revealed a peak in 2015 and minimum in 2013. Subsequently, a time-series of phytoplankton species images were generated for these 2 years to study their inter-annual variability and the associated factors. Species images during active phase of the bloom (February) in 2015 indicated development of N. scintillans and diatom in the central Arabian Sea also, up to 12° N. This observation was substantiated with relevant oceanic parameters measured from the ship as well as satellite data and the same is highlight of the paper. While oxygen depletion and release of ammonia associated with N. scintillans are detrimental for waters on the western side; it is relatively less extreme and supports the entire food chain on the eastern side. In view of these contrasting eco-sensitive events, it is a matter of concern to identify biologically active persistent areas, hot spots, in order to study their ecology in detail. An ecological index, persistence of the bloom, was derived from the time-series of species images and it is another highlight of our study.

Outcome of Both Bone Forearm Fracture Fixation in Children by Rush Nails

INTRODUCTION

Forearm fractures are common upper limb injuries among children and usually treated non-operatively. Failure of non-operative treatment, open injuries and multiple fractures are the indications for surgery in paediatric both bone forearm fractures. Intramedullary nailing is considered as minimally invasive procedure with excellent to fair outcomes but it is not free of complications. We reviewed the results and evaluated the outcomes of IM fixation of forearm fractures in children by Rush nails to understand the risks and complications associated with these procedures.

METHODS

A retrospective crossectional study of all paediatric patients treated for diaphyseal forearm fractures for period of five years in a tertiary care setup. Complications were classified according to modified Clavien-Dindo complication classification system. Outcomes were graded depending upon complication grade along with range of motion of forearm.

RESULTS

A total of 25 patients were included in the study. Mean time for fracture union was 10.56 weeks. Outcomes were excellent in 16 (64%), good in 7 (28%), fair in 2 (8%) patients and no poor outcome was noted. Ten minor complications were seen.

CONCLUSION

Fixation of paediatric forearm fractures by intramedullary Rush nail is minimally invasive procedure and outcomes are excellent to fair with acceptable complication rates.

Species identification of mixed algal bloom in the Northern Arabian Sea using remote sensing techniques

Oceanic waters of the Northern Arabian Sea experience massive algal blooms during winter-spring (mid Feb-end Mar), which prevail for at least for 3 months covering the entire northern half of the basin from east to west. Ship cruises were conducted during winter-spring of 2001-2012 covering different stages of the bloom to study the biogeochemistry of the region. Phytoplankton analysis indicated the presence of green tides of dinoflagellate, Noctiluca scintillans (=N. miliaris), in the oceanic waters. Our observations indicated that diatoms are coupled and often co-exist with N. scintillans, making it a mixed-species ecosystem. In this paper, we describe an approach for detection of bloom-forming algae N. scintillans and its discrimination from diatoms using Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua data in a mixed-species environment. In situ remote sensing reflectance spectra were generated using Satlantic™ hyperspectral radiometer for the bloom and non-bloom waters. Spectral shapes of the reflectance spectra for different water types were distinct, and the same were used for species identification. Scatter of points representing different phytoplankton classes on a derivative plot revealed four diverse clusters, viz. N. scintillans, diatoms, non-bloom oceanic, and non-bloom coastal waters. The criteria developed for species discrimination were implemented on MODIS data and validated using inputs from a recent ship cruise conducted in March 2013.

Close Versus Limited Open Method of Ender's Nail Fixation in Paediatric Femoral Shaft Fractures

INTRODUCTION

There are various surgical options for treating fracture of femoral shaft in children. Here we compare the results of close with limited open method of Ender's nails fixation of femoral shaft fractures in children.

METHODS

We studied 60 children with femoral shaft fractures in age group 5-15 years. Ender's nail fixation was done by close technique in 40 cases and in 20 cases by limited open technique.

RESULTS

The mean operative time was significantly high in limited open group being 64 minutes in comparison to 50 minutes in close group. There was no significant difference between close and limited open groups with respect to time for partial weight bearing and time for full weight bearing. Fracture united sooner in close group as compared to open group. Union was achieved in all patients within a mean of 11 weeks in close group in comparison to 12.4 weeks in open group. According to the Flynn criteria in close group 34 patients had excellent results, 6 had satisfactory and none poor. In limited open group outcome was excellent in 14 patients, satisfactory in 4 patients and 2 had poor result. There was no significant difference in outcome based on Flynn criteria between two groups.

CONCLUSIONS

Though operative time is more and healing is delayed in Ender's nail fixation by limited open technique, there is no statistical difference in final outcome as per Flynn criteria between close and limited open technique of Ender's nail fixation of femoral shaft fractures in children.

Can community-based, low-cost antenatal care in the third trimester of pregnancy reduce the incidence of low birth weight newborns?

OBJECTIVE

To determine if community-based, low-cost interventions during third trimester of pregnancy can reduce the incidence of low birth weight babies.

METHODS

In a case control study, 290 pregnant women from a slum area were registered in the beginning of third trimester of pregnancy and provided full antenatal care comprising fortnightly check up, one IFA tablet daily, counseling for minimum one-and-a-half hour post-lunch rest in left lateral position, additional diet to ensure minimum 2,200 kcal per day, and management of clinical conditions, if any. An equal number of pregnant women belonging to the same slum area were registered as control who received routine antenatal services from the existing health care facilities. The birth weight of the babies in the two groups were recorded and compared. Test of significance and correlation coefficient were applied to the data.

RESULTS

Mean birth weight of the babies of the Subjects was 2.76 kg (SD 0.39) compared to mean birth weight of 2.57 kg (SD 0.36) of the babies in the Control group. Incidence of low birth weight babies among subjects who consumed minimum 2,400 kcal per day, had one-and-a-half hour post-lunch rest in left lateral position and who consumed one tablet of IFA (100 mg iron and 5 mg folic acid) per day during the last trimester of pregnancy was lower (17.6 %) as compared with women in the Control group (36.2 %). The difference in the mean birth weight of newborns of the two groups was statistically significant (t = 2.52, p < 0.01).

CONCLUSIONS

Incidence of low birth weight babies can be significantly reduced by providing simple, low-cost care to pregnant women during the last trimester of pregnancy in the community setting.

Surgical Management of Cervical Spondylotic Myelopathy

Introduction: The surgical procedure by the anterior, posterior and combined antero-posterior approaches had applied for the treatment of cervical spondylotic myelopathy.  Methods: During the treatment process, all patients were pre-operatively as well post-operatively graded according to Japanese Orthopaedics Association. Several surgical methods such as anterior approach, posterior approach, and combined antero-posterior approach have been addressed for CSM patients, with the choice based on the pathogenesis of the myelopathy. The main indications for surgery were evidence of myelopathy on physical examinations, a JOA score below 13 points help with spinal cord compression observed on plain X-ray, CT scan, MRI studies.  Results: The pre-operative JOA scores were 7.60±1.23 in laminoplasty, 8.30±1.03 in diskectomy and corpectomy and 7.10±1.20 in combined antero-posterior approach patients. At the follow-up after three months the JOA scores were laminoplasty 13.30±1.30, diskectomy and corpectomy 13.55±1.15 and combined antero-posterior 13.50±1.08. The JOA recovery rate averaged, 61.08±11.25% in laminoplasty, 60.67±10.60% in diskectomy and corpectomy and 64.67±10.72% in combined anteroposterior approach. The high- signal intensity changed to normal in 18 out of 28 and no any kyphotic change and instability were found in cervical spine at the follow up.  Conclusions: Patients with OPLL (continuous, segmental and mixed type), stenosis of cervical spinal canal, multilevel cervical spondylosis, large and high ossification of IVDP with stenosis were improved with laminoplasty. Patients with PIVD, CSM with kyphosis, post laminectomy , OPLL herniated type, unstable vertebral alignment, stenosis by osteophytes, were improved with anterior approach . Ossified or deformed OPLL, unstable vertebral with stenosis ,OPLL or OYL with cervical meandearing (swan-neck) were improved with Combined anterior and posterior approach. Keywords: cervical spondylotic mylopathy, anterior cervical diskectomy and fusion, corpectomy.

Surgical management of cervical spondylotic myelopathy

INTRODUCTION

The surgical procedure by the anterior, posterior and combined antero-posterior approaches had applied for the treatment of cervical spondylotic myelopathy.

METHODS

During the treatment process, all patients were pre-operatively as well post-operatively graded according to Japanese Orthopaedics Association. Several surgical methods such as anterior approach, posterior approach, and combined antero-posterior approach have been addressed for CSM patients, with the choice based on the pathogenesis of the myelopathy. The main indications for surgery were evidence of myelopathy on physical examinations, a JOA score below 13 points help with spinal cord compression observed on plain X-ray, CT scan, MRI studies.

RESULTS

The pre-operative JOA scores were 7.60±1.23 in laminoplasty, 8.30±1.03 in diskectomy and corpectomy and 7.10±1.20 in combined antero-posterior approach patients. At the follow-up after three months the JOA scores were laminoplasty 13.30±1.30, diskectomy and corpectomy 13.55±1.15 and combined antero-posterior 13.50±1.08. The JOA recovery rate averaged, 61.08±11.25% in laminoplasty, 60.67±10.60% in diskectomy and corpectomy and 64.67±10.72% in combined antero-posterior approach. The high-signal intensity changed to normal in 18 out of 28 and no any kyphotic change and instability were found in cervical spine at the follow up.

CONCLUSIONS

Patients with OPLL (continuous, segmental and mixed type), stenosis of cervical spinal canal, multilevel cervical spondylosis, large and high ossification of IVDP with stenosis were improved with laminoplasty. Patients with PIVD, CSM with kyphosis, post laminectomy, OPLL herniated type, unstable vertebral alignment, stenosis by osteophytes, were improved with anterior approach. Ossified or deformed OPLL, unstable vertebral with stenosis, OPLL or OYL with cervical meandearing (swan-neck) were improved with Combined anterior and posterior approach.

Problem based review: the patient presenting with an acutely swollen arm

A 69 year old female presented to the Emergency Department with swelling of her right arm and elbow, one week following a fall which resulted in a fracture of the middle third of her right clavicle (Figure 1). The forearm was hot and tender and the arm and hand function were somewhat impaired by swelling, but sensation was intact. Initial bloods were unremarkable, apart from a mild neutrophilia.

An ultrasonographic evaluation of solitary muscular and soft tissue cysticercosis

BACKGROUND

Cysticercosis in humans is infection with the larval form (cysticercus cellulosae) of the pork tapeworm T. solium. Encystment of larvae can occur in almost any tissue. The location of cysts in order of frequency is the central nervous system, subcutaneous tissue and striated muscle, vitreous humour of the eye and, rarely, other tissues. High resolution ultrasound can be used in the diagnosis of muscular and soft tissue cysticercosis.

OBJECTIVE

The aim of this study is to evaluate the ultrasonographic findings in cases of muscular and soft tissue cysticercosis.

MATERIALS AND METHODS

It was a retrospective review of the cases of muscular and soft tissue cysticercosis which were diagnosed by ultrasound during June 2007 to May 2009 in the department of Radiology and Imaging, Nepalgunj Medical College Teaching Hospital. A total of six patients were evaluated.

RESULT

There were four males and two females. Age of the patient ranged from 18 to 50 years. All of the patients presented with a swelling with pain in fi ve of them. There was a wide variation in the location of the cysts. In all cases ultrasound revealed a cystic lesion with an echogenic eccentric pedunculated nodule attached to the wall. The mean diameter of the cyst was 6mm. Smooth wall was present in fi ve cases whereas one of the cysts revealed irregular wall. Pericystic inflammatory changes were seen in the adjacent muscles.

CONCLUSION

Ultrasound is a safe and non-invasive method that can be used in the diagnosis of muscular and soft tissue cysticercosis.

Block of Inward Rectifying K + Channels (K IR ) Inhibits Bradykinin-Induced Vasodilatation in Human Forearm Resistance Vasculature

Objective— To investigate the possible involvement of inward rectifying K + channels (K IR ) in the response of human resistance vessels to bradykinin in vivo.

Methods and Results— Drugs were administered via the brachial artery in healthy male volunteers and forearm blood flow was measured by venous occlusion plethysmography. Inhibition of K IR by barium chloride (4 μmol min −1 ) alone or with additional inhibition of Na + /K + ATPase (ouabain 2.7 μmol min −1 ) reduced responses to bradykinin (30 pmol min −1 ), by 26±8.3% and 36±7.2%, respectively (each P <0 0.05). Barium with ouabain plus inhibitors of prostaglandin (PG) and nitric oxide synthesis inhibited but did not abolish responses to bradykinin (51±2.8% inhibition; P <0.01); norepinephrine (240 pmol min −1 ) caused similar reduction of baseline blood flow, as did this combination of inhibitors, but did not significantly inhibit the response to bradykinin. Barium plus ouabain did not significantly reduce responses to acetylcholine or albuterol.

Conclusion— A component of the vasodilator response to bradykinin in human forearm vasculature is mediated by K IR .

Constitutive expression of prostaglandin endoperoxide G/H synthetase (PGHS)-2 but not PGHS-1 in hum an tracheal epithelial cells in vitro

Primary cultures of human tracheal epithelial (HTE) cells cultured in vitro, in defined serum-free media, express prostaglandin endoperoxide G/H synthase (PGHS) activity and produce prostaglandin E2 (PGE2). In contrast to every other cell type studied to date, HTE cells appear to constitutively express PGHS-2, the 'inducible' form of the enzyme, while expressing little or no PGHS-1, the 'housekeeping' isoenzyme in vitro. Prostaglandin synthesis in HTE cells was reduced by a selective PGHS-2 inhibitor, N-[2-cyclohexyloyl-4-nitrophenyl] methane-sulfonamide (NS398), with an IC50 of approximately 1 microM. Immunoblotting and immunoprecipitation of enzymatic activity with isozyme-specific antisera revealed only the PGHS-2 isoform. Full length human cDNA probes detected only PGHS-2 message in Northern blots. Neither PGHS-2 activity nor mRNA levels were dependent on, nor stimulated by peptide growth factors present in the defined serum-free growth medium, or by serum. Prolonged maintenance in the absence of retinoic acid, however, lead to a decline in PGHS activity. Phorbol-myristate acetate (PMA) induced PGHS-2 activity and mRNA and neither PMA-induced, nor constitutive PGHS-2 expression was suppressed by corticosteroids. Actinomycin D-treatment for six hours reduced the PGHS-2 activity and mRNA to only 50% that of untreated cells, suggesting that PGHS-2 mRNA is extremely stable in these cells. HTE cells, at least in vitro, appear unique among prostaglandin-producing cells in that they express PGHS-2, constitutively, independent of regulation by growth factors, serum, or corticosteroids and fail to express PGHS-1 under any culture condition studied.