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.

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.

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.

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.