Role of Lymphovascular Invasion in Oral Cavity Squamous Cell Carcinoma Regional Metastasis and Prognosis

OBJECTIVE

The overall 5-year survival for oral squamous cell carcinoma (OSCC) has not changed in the last 20 years despite advances in treatment. Lymphovascular invasion (LVI) has been shown to be a negative prognostic factor in other cancers, however its role in the prognosis of OSCC remains unclear. This study aims to determine if LVI is a predictor of cervical lymph node metastasis and/or recurrence in OSCC.

METHODS

We conducted a retrospective cohort review of patients from our institutional cancer registry who were treated for OSCC between 2004 and 2018. Patient demographics, surgical pathology results, and clinical outcome data were collected. A multivariable logistic regression analysis was performed to determine if LVI was an independent predictor of cervical lymph node metastasis and/or recurrence.

RESULTS

442 patients were included, 32.8% were female and median age at time of diagnosis was 61.2 years. LVI was present in 32.8% of patients. When controlled for age, sex, t-classification, perineural invasion, depth of invasion (DOI), and margin status, LVI was a significant predictor of the presence of cervical node metastasis (OR: 3.42, CI: 2.17-5.39, P < .001). There was no significant association found between LVI and local recurrence (OR: 1.03, CI: 0.57-1.84, P = .92), regional recurrence (OR: 1.10, CI: 0.57-2.11, P = .78), or distant recurrence (OR: 1.59, CI: 0.87-2.94, P = .13).

CONCLUSION

The results of this study suggest that LVI is a significant predictor of the presence of cervical lymph node metastasis at presentation independent of other known prognostic factors. LVI, however, was not found to be a significant independent predictor of locoregional or distant recurrence.Level of Evidence: Level III.

Prognostic Implications of Skin Invasion in Locally Advanced Oral Cavity Squamous Cell Carcinoma

OBJECTIVE

To evaluate the effect of histopathologic skin invasion on 2- and 5-year disease-free survival (DFS) and overall survival (OS) in patients treated with primary surgery for locally advanced oral cavity squamous cell carcinoma (OCSCC).

STUDY DESIGN

A retrospective case-control study was performed comparing previously untreated patients with pT4a OCSCC with and without skin invasion.

SETTING

Academic medical center.

METHODS

Propensity score-matched cohorts were derived by age, sex, surgical margins, pathologic N classification, adjuvant treatment, and primary tumor site. The Kaplan-Meier method was used to evaluate 2- and 5-year OS and DFS, which were compared between cohorts via the log rank (Mantel-Cox) test statistic.

RESULTS

Overall 25 patients were identified to have pathologic skin invasion, and 50 were selected for the matched control group. OS was significantly lower for patients with skin invasion as compared with controls at 2 years (30.8% vs 53.3%, P = .018) and 5 years (16.6% vs 42.2%, P = .01). DFS was significantly lower for patients with skin invasion vs controls at 2 years (23.7% vs 47.7, P = .037) and 5 years (15.8% vs 41.4%, P = .024).

CONCLUSION

Histopathologic skin invasion in OCSCC is associated with dismal prognosis in patients who underwent primary surgical treatment. OS outcomes for patients with skin invasion are comparable to survival of patients with recurrent/metastatic disease and T4N2 disease.

Microplastics assessment in Arabian Sea fishes: accumulation, characterization, and method development

Around the globe, plastic has been entering the aquatic system and is ingested by organisms. Identification, optimal digestion method, and characterization of the polymers to trace sources are of growing importance. Hence, the present work investigated microplastics accumulation, digestion protocol efficiency, and characterization of polymers with FTIR analysis in the guts of five fishes (Lethrinus nebulosus, Rastrelliger kanagurta, Acanthopagrus arabicus, Otolithes ruber, and Euryglossa orientalis) from the Karachi coastal area, Arabian Sea. A total of 1154 microplastics (MPs) were ingested by 29 out of 33 fish species (87%). The highest average MP/fish was recorded in Otolithes ruber (54) and the lowest in Rastrelliger kanagurta (19.42). Microfibers were the most abundant shape with the highest numbers (35.52%) as compared to the rest of the MPs identified. Transparent microfibers were recorded as the highest in numbers followed by red, black, blue, and green. In this study, KOH with different concentrations and exposure times along with oxidizing agent hydrogen peroxide was tested (Protocols 3 and 4). Results showed these bases were highly efficient in obtaining optimal digestion of the samples. FTIR analysis confirmed that the majority of the polymers found in the fish guts were polyethylene and polypropylene. This study validated for the first time the presence of these polymers of plastic in marine fish from Pakistan.

Neurosarcoidosis Presenting as Isolated Bilateral Cerebellopontine Angle Tumors: Case Report and Review of the Literature

OBJECTIVES

To describe a unique case of isolated bilateral sarcoidosis of the cerebellopontine angle as well as the related imaging in the case. To conduct a literature review of the published articles regarding sarcoidosis of the cerebellopontine angle.

DATA SOURCES

Representative case report from a single institution as well as PubMed and Scopus database searches.

METHODS

In addition to a retrospective review, all published case reports and case series of sarcoidosis involving the cerebellopontine angle from 1960 to July 2018 in the English language were reviewed. Demographic data, presenting symptoms, and outcomes were collected.

RESULTS

We identified 8 total cases with pertinent clinical information that were included.

CONCLUSIONS

Isolated neurosarcoidosis of the cerebellopontine angle is an exceptionally rare phenomenon that, on history and imaging, presents similar to more common retrocochlear pathologies. Surgery may be required in large lesions unresponsive to traditional medical therapy with immunosuppression.

The Utility of Computed Tomography and Intrathecal Fluorescein in the Management of Cerebrospinal Fluid Leak

Background

Intrathecal fluorescein (IF) has become a common tool for localization of cerebrospinal fluid (CSF) leak, but despite frequent use, IF lacks Food and Drug Administration approval. The diagnostic ability of high-resolution computed tomography (HRCT) has increased over several decades. Subspecialized rhinology training within otolaryngology has, similarly, allowed for dedicated skull base surgeons to become more adept at CSF leak localization.

Objectives

To evaluate the utility of HRCT and IF in CSF leak localization. To identify certain patient populations in which IF has added utility. To analyze the ability of fellowship-trained neuroradiologist and rhinologist to localize CSF leak sites.

Methods

Data were collected from a single, tertiary care academic institution. Patients admitted for CSF leak between 2003 and 2016 were included. Diagnostic yield of preoperative imaging and IF for identification of leak site was analyzed. Fellowship-trained neuroradiologist and rhinologist performed retrospective review of CT imaging and identified CSF leak sites.

Results

One hundred and two patients underwent CSF leak repair. Skull base defects were preoperatively localized to exact sinus on imaging report in 67% of patients. Preoperative imaging stratified by CT slice thickness of 0.625 mm identified leak site in 88.9% of cases. Blinded retrospective review by a neuroradiologist and rhinologist was able to localize the CSF leak to the correct or adjacent sinus in >80% of cases. IF was useful for intraoperative localization in 73% of cases. When preoperative imaging failed at leak site localization, IF was able to correctly identify leak site in 75% of cases.

Conclusions

The diagnostic yield of IF and CT imaging was equivalent, with each modality localizing leak site approximately two-thirds of the time. CT imaging with 0.625 mm slice thickness proved more efficacious in identification of skull base defects. IF demonstrated increased utility in instances where preoperative imaging has failed at leak site identification.

Atypical Form of Cervicofacial Actinomycosis Involving the Skull Base and Temporal Bone

BACKGROUND:

Cervicofacial actinomycosis is an uncommon indolent infection caused by Actinomyces spp that typically affects individuals with innate or adaptive immunodeficiencies. Soft tissues of the face and neck are most commonly involved. Actinomyces osteomyelitis is uncommon; involvement of the skull base and temporal bone is exceedingly rare. The authors present a unique case of refractory cervicofacial actinomycosis with development of skull base and temporal bone osteomyelitis in an otherwise healthy individual.

METHODS:

Case report with literature review.

RESULTS:

A 69-year-old man presented with a soft tissue infection, culture positive for Actinomyces, over the right maxilla. Previous unsuccessful treatment included local debridement and 6 weeks of intravenous ceftriaxone. He was subsequently treated with conservative debridement and a prolonged course of intravenous followed by oral antibiotic. However, he eventually required multiple procedures, including maxillectomy, pterygopalatine fossa debridement, and a radical mastoidectomy to clear his disease. Postoperatively he was gradually transitioned off intravenous antibiotics.

CONCLUSIONS:

Cervicofacial actinomycosis involves soft tissue surrounding the facial skeleton and oral cavity and is typically associated with a history of mucosal trauma, surgery, or immunodeficiency. The patient was appropriately treated but experienced disease progression and escalation of therapy. Although actinomycosis is typically not an aggressive bacterial infection, this case illustrates the need for prompt recognition of persistent disease and earlier surgical intervention in cases of recalcitrant cervicofacial actinomycosis. Chronic actinomycosis has the potential for significant morbidity.

Tinnitus perception in patients after vagal nerve stimulator implantation for epilepsy

PURPOSE

Vagal nerve stimulation in conjunction with sound therapy has been proposed as a treatment for subjective tinnitus. The purpose of this study is to retrospectively review the effect of VNS on perception of tinnitus in epilepsy patients. We explore the incidence of tinnitus and its perceived reduction in patients requiring implantation of VNS for medically refractory seizures.

MATERIALS AND METHODS

A phone survey was conducted in adult patients with prior VNS implantation. A questionnaire including the visual analog scale (VAS) of tinnitus loudness was used to determine the presence and severity of tinnitus.

RESULTS

Out of the 56 patients who had completed the phone survey, 20 (35%) reported the presence of pre-operative tinnitus. The tinnitus positive group was significantly older (p = 0.019). Of the 20 pre-operative tinnitus positive patients, all patients continued to have tinnitus post-operatively. Four (20%) noted no changes in VAS of tinnitus loudness while 16 (80%) had at least a one-point decrease. The mean difference between pre- and post-operative VAS of loudness was 2.05, with a standard deviation of 1.84 and this was statistically significant (p < 0.001).

CONCLUSIONS

In this study, we evaluate the potential of vagal nerve stimulation to alter the perception of tinnitus in patients with refractory epilepsy. Eighty percent of patients noted some level of subjective tinnitus improvement after VNS implantation. Given this finding, there may be a potential additional benefit to the use of VNS in patients with epilepsy.

Priorities in the Neurotology Fellowship Match: A Survey Study of Program Directors and Fellows

OBJECTIVES

To ascertain motivations and priorities for neurotology fellowship applicants and program directors during the match process.

METHODS

Anonymous online survey distributed to 20 fellowship program directors and 40 current and incoming neurotology fellows. A 5-point Likert scale was used to assess the priorities of fellowship applicants and program directors in the match process.

RESULTS

Twenty-four of 40 (60%) current or incoming fellows and 14 of 20 (65%) program directors responded to the survey. Fellows rated surgical exposure and volume as their highest priorities. In addition to neurotology case load, fellows highly valued exposure to otologic surgery. Salary, call, and work/life balance were among the lowest rated factors among fellows. Program directors attached the highest priority to the applicant interview performance, followed by strength of letters of recommendation and quality of prior research. Ethnicity, sex, and likelihood of an applicant ranking a program highly were the lowest rated factors among program directors.

CONCLUSION

Among neurotology fellows, operative case load and breadth of surgical exposure are highly valued components of accredited fellowship training. Among neurotology fellowship program directors, candidates' performance during the fellowship interview appears to be highly valued, more so than the strength of applicants' letters of recommendation or prior research credentials.

Steroid Versus Antibiotic Drops in the Prevention of Postoperative Myringotomy Tube Complications

Objectives:

To determine the incidence of early postoperative tympanostomy tube insertion otorrhea and obstruction in pediatric patients receiving antibiotic ear drops with or without steroid perioperatively.

Methods:

A retrospective chart review was performed on patients who underwent outpatient myringotomy and tube placement. Patients from June 2013 to February 2014 received ciprofloxacin/dexamethasone perioperatively while patients from May 2014 to April 2015 received ofloxacin. Statistical analysis was performed to compare outcomes between the cohorts.

Results:

One hundred thirty-four patients received topical ciprofloxacin/dexamethasone, and 116 patients received topical ofloxacin. The rate of postoperative otorrhea was 5.2% for the ciprofloxacin/dexamethasone group and 8.2% for the ofloxacin group. Tube obstruction was seen in 6.0% of the ciprofloxacin/dexamethasone group and 5.2% in the ofloxacin group. Neither outcome had a statistically significant difference ( P = .21 and .85, respectively). There was no difference in the rate of effusion at the time of tube placement between the 2 cohorts ( P = .16), and this included subgroup analysis based on effusion type (mucoid, purulent, serous). Patients with a mucoid effusion at the time of surgery were more likely to experience otorrhea/obstruction than patients with dry ears (odds ratio = 2.23, P = .02).

Conclusion:

No significant difference in the incidence of immediate postoperative tympanostomy tube otorrhea or obstruction was seen between the antibiotic-steroid and antibiotic alone cohorts, regardless of effusion type. Overall, patients with mucoid effusions are more likely to develop tube otorrhea or obstruction at follow-up. Cost-effective drops should be used when prescribing topical therapy to prevent complications after ear tubes.

Alginate Ototoxicity in the Mouse Model

Objective To determine whether alginate exposure to the round window of the mouse causes any measurable ototoxicity. Study Design Prospective animal study. Setting Basic science laboratory affiliated with a tertiary care university medical center. Subjects and Methods After Institutional Animal Care and Use Committee approval, 5 adult mice were obtained and underwent bullostomy and round window niche application of alginate. Auditory brainstem response (ABR) tests were completed at baseline prior to the procedure and also 5, 14, and 30 days postprocedure. Results were compared. At termination of procedure, the mice were sacrificed with harvest of the cochleae, which were viewed under histologic section. Results There were no significant increases in ABR thresholds in any of the test animals at all test periods after alginate exposure compared to baseline. There were also no observable behavioral changes after the procedure to indicate vestibular dysfunction. Cochlear sectioning revealed no evidence of histologic damage. Conclusion Exposure of alginate to the round window does not cause any obvious ototoxicity in the mouse model. Further clinical trials will be needed to elucidate the effect of alginate in the human middle ear.

Bilateral Ossicular Head Dehiscence Into the Middle Cranial Fossa

OBJECTIVES

To describe a unique case of bilateral dehiscence of the malleus and incus heads into the middle fossa making contact with the temporal lobes, along with its clinical implications.

METHODS

An analysis of a patient case and review of pertinent literature were performed.

RESULTS

A patient with a history of right-sided mastoidectomy for cholesteatoma was evaluated for persistent conductive hearing loss. On computed tomography (CT) and magnetic resonance imaging (MRI), the patient had a complete dehiscence of the tegmen tympani on the right, with ossicular heads being located above the floor of the middle cranial fossa. A similar finding to a milder degree was noted on the left. The patient underwent revision tympanoplasty with mastoidectomy with removal of the incus and ossicular chain reconstruction and middle fossa craniotomy for repair of the right epitympanic dehiscence.

CONCLUSIONS

We present some of the unique imaging and operative findings involved in an unusual presentation of encephalocele in which the bilateral malleus and incus heads rise above the level of the middle fossa floor.

'Halomonas saudii' sp. nov., a new bacterial species isolated from marine plant Halocnemum strobilaceum

We report here the main characteristics of 'Halomonas saudii' strain Saudii DR2 (CSUR P2512), a new species of the Halomonas genus that was isolated from a rhizosphere of Halocnemum strobilaceum in April 2015.

The effects of a cytokine suppressive anti-inflammatory drug on the output of prostaglandin E(2) and interleukin-1 beta from human fetal membranes

Fetal membranes are a primary source of prostaglandins and pro-inflammatory cytokines implicated in human parturition, so the inhibition of inflammatory pathways may be of benefit in pregnancies complicated by premature labour. We have therefore investigated the effects of a cytokine-suppressant anti-inflammatory drug (CSAID) on the output of prostaglandin E(2) (PGE(2)) and interleukin (IL)-1 beta from human fetal membranes in vitro. Bacterial endotoxin increased the expression of mRNA for IL-1 beta and type-2 cyclo-oxygenase (COX-2), and there were corresponding increases in the output of IL-1 beta protein and PGE(2). The CSAID decreased IL-1 beta protein, COX-2 expression and PGE(2) output, but not mRNA for IL-1 beta, indicating a post-translational effect on the production of IL-1 beta and a transcriptional affect on COX-2, with an overall reduction in PGE(2). These findings are consistent with the effects of CSAIDs in other systems, and indicate that they are of possible use in premature labour.

The regulation of prostaglandin output from term intact fetal membranes by anti-inflammatory cytokines

Prostaglandins are some of the main mediators which control parturition, and their production by intrauterine tissues can be up-regulated by pro-inflammatory cytokines. Anti-inflammatory cytokines may oppose these effects, and in this study we have investigated how two such cytokines affected fetal membrane function. Interleukin-10 (IL-10) inhibited the output of prostaglandin E2 (PGE2) from intact fetal membranes under basal and lipopolysaccharide (LPS)-stimulated conditions, and there was a parallel decrease in the expression of mRNA for COX-2. IL-10 also inhibited the production of interleukin-1beta (IL-1beta) and the expression of mRNA for IL-1beta, indicating that this cytokine has a broad anti-inflammatory effect. Transforming growth factor-beta1 (TGF-beta1), which is generally considered to be anti-inflammatory had opposite effects on PGE2 production, in that it increased the output of PGE2 for up to 8 hr. TGF-beta1 increased levels of type-2 cyclo-oxygenase (COX-2) and cytosolic phospholipase A2 (cPLA2) protein, and also activated the cPLA2 enzyme present; the profile of effects is similar to that of the pro-inflammatory cytokine IL-1beta, and was not expected. Combinations of TGF-beta1 with IL-1beta also increased PGE2 output and caused appropriate changes in prostaglandin pathway enzymes, whereas TGF-beta1 and IL-1alpha had more limited effects. Further studies are needed to establish the physiological significance of these findings, but TGF-beta1 does not seem to act as an inhibitory cytokine in intact fetal membranes at term.

Expression of 5-lipoxygenase and 5-lipoxygenase-activating protein in human fetal membranes throughout pregnancy and at term

Lipoxygenase metabolites may be involved in human parturition. 5-lipoxygenase (5-LOX) catalyses the first steps in the synthesis of leukotrienes from arachidonic acid, and its activity is dependent on 5-LOX activating protein (FLAP). The expression of 5-LOX and FLAP were investigated in fetal membranes to determine whether there are changes with gestational age or at term with the onset of labour. No significant differences were found in the expression of 5-LOX or FLAP mRNA in the amnion at different gestational ages or at term. In the chorion-decidua, 5-LOX mRNA expression was significantly higher in the first trimester of pregnancy than in the second and third trimesters. At term, there was a significant increase in both 5-LOX mRNA and protein expression in the chorion-decidua in the time after labour, compared with the time before labour. The expression of FLAP mRNA was also significantly higher in the chorion-decidua in the first trimester of pregnancy compared with the third trimester, and at term in the time after labour compared with the time before labour. Expression of FLAP protein was not studied, as an antibody is not currently available. These results are consistent with a role for 5-LOX and FLAP in the control of parturition at term, and also suggest an involvement earlier in pregnancy.

The production of interleukin-1beta from human fetal membranes is not obligatory for increased prostaglandin output

Bacterial endotoxin increased the expression of mRNA (maximal after 4 hr) for interleukin-1beta (IL-1beta) and the release of mature protein from intact human fetal membranes. In contrast, the change in expression of mRNA for type 2 cyclo-oxygenase (COX-2) was biphasic, with peaks after 0.5-1 hr and after 8 hr of culture. An antibody to IL-1beta was without effect after 4 hr of culture, inhibited endotoxin-stimulated prostaglandin E2 (PGE2) production after 8 hr of culture, and caused a parallel decrease in the expression of mRNA for COX-2. We conclude that endotoxin induced the expression of COX-2 through IL-1beta-independent and IL-1beta-dependent mechanisms, and these differences are time dependent. Corticotrophin-releasing hormone (CRH) or platelet-activating factor (PAF) also increased the expression of mRNA for IL-1beta and the release of IL-1beta from some, but not all, fetal membranes. The antibody to IL-1beta did not affect CRH-stimulated or PAF-stimulated PGE2 production or COX-2 expression. We conclude that CRH and PAF can induce the expression of IL-1beta, but this is not obligatory for increased PGE2 release, and the effect of these stimuli on COX-2 expression is a direct, IL-1beta-independent effect.

Corticotrophin-releasing hormone and platelet-activating factor induce transcription of the type-2 cyclo-oxygenase gene in human fetal membranes

Corticotrophin-releasing hormone (CRH) and platelet-activating factor (PAF) are considered to be involved in the physiological processes of human labour. Both may have dual effects, directly regulating myometrial contractility and fetal membrane prostaglandin production. During this study, we investigated the mechanisms through which CRH and PAF exert their latter effect. CRH and PAF increased prostaglandin production from intact fetal membrane discs, with a maximum stimulation after 8 h of culture. Reverse transcription-polymerase chain reaction (RT-PCR) analyses using primers specific for type-2 cyclo-oxygenase (COX-2) showed that CRH and PAF increased the transcription of COX-2 mRNA two-fold after 8 h culture. These data indicate that the increased fetal membrane prostaglandin production in response to CRH or PAF may involve the induction of COX-2.

Regulation of prostaglandin production in intact fetal membranes by interleukin-1 and its receptor antagonist

There is strong evidence for the involvement of inflammatory mediators such as interleukin (IL)-1 in the biochemical mechanisms of parturition. Therefore the effects of the IL-1 family (IL-1alpha (1 ng/ml), IL-1beta (1 ng/ml) and the IL-1 receptor antagonist (IL-1ra) (10 ng/ml)) on the regulation of prostaglandin synthesis in term human fetal membranes were investigated. It was found that, after 4 h of culture, IL-1beta increased prostaglandin E2 (PGE2) output approximately twofold. This was associated with both a significant increase in cyclo-oxygenase-2 (COX-2) mRNA levels (approximately fourfold compared with control) and translocation of cytoplasmic phospholipase A2 (cPLA2) from the cytosol to the membrane fraction. IL-1alpha was less effective than IL-1beta at stimulating PGE2 production through similar mechanisms. IL-1ra had no effect on PGE2 output. However, in combination treatments, IL-1ra did not inhibit IL-1alpha- or IL-1beta-stimulated PGE2 output, and increased PGE2 production further compared with IL-1beta alone. IL-1ra decreased IL-1beta-induced COX-2 mRNA expression by about half and significantly increased cPLA2 protein levels, as detected by immunoblotting, when used alone and together with IL-1beta. These results suggest that IL-1ra has partial agonist properties when used together with IL-1alpha and IL-1beta in fetal membranes by increasing cPLA2 protein levels, which leads to an increase in the production of prostaglandins.

Interleukin-1beta and bacterial endotoxin change the metabolism of prostaglandins E2 and F2alpha in intact term fetal membranes

There is strong evidence that prostaglandins E2 and F2alpha (PGE2 and PGF2alpha) are involved in the initiation and maintenance of human parturition and that their production can be stimulated by a number of cytokines and in infection-induced preterm labour by bacterial endotoxin. This study used an intact fetal membrane disk model to investigate the regulation of PGE2 and PGF2alpha metabolism by interleukin-1 beta (IL-1beta) and bacterial endotoxin [lipopolysaccharide (LPS)]. Fetal membrane explants were incubated with IL-1beta (0.1 or 1.0 ng/ml) or LPS (10 ng/ml) for 24 h. A mixture of 3H-prostaglandin (0.1 microCi) and unlabelled prostaglandin (1 microg) was then added at selected times after the addition of inflammatory mediators. The radiolabelled prostaglandins and their metabolites were then extracted from the culture medium and quantified by high-pressure liquid chromatography. Levels of prostaglandin metabolites were generally decreased following incubation with IL-1beta or LPS, which is consistent with a decrease in the activity of 15-hydroxyprostaglandin dehydrogenase (PGDH). It is concluded that IL-1beta and LPS moderately decrease the metabolism of prostaglandins, which may contribute to increasing the local levels of active prostaglandins induced by these stimuli.

Stimulation of prostaglandin production from intact human fetal membranes by bacteria and bacterial products

The addition of live or sonicated Escherichia coli, or endotoxin from E. coli increased the release of prostaglandins (PG) on both sides of intact human fetal membranes after 24 h of incubation, indicating that live bacteria were not required to activate prostaglandin production. Time-course studies showed that the levels of PGE2 and PGF2alpha on the fetal side of the membrane were increased 6 h after the addition of endotoxin, whereas levels on the maternal side increased within 1-2 h. These changes were independent of the side to which the endotoxin was added, indicating that a stimulatory factor passes through the fetal membranes. This factor is not endotoxin, which did not cross the membranes, and further studies are required to identify this endogenous stimulus. Prostaglandin metabolite levels were either unaffected or increased by endotoxin, indicating that the main effect is at the level of increased prostaglandin biosynthesis rather than decreased metabolism.

A spontaneous induction of fetal membrane prostaglandin production precedes clinical labour

Fetal membranes from term human pregnancies produce prostaglandins, and may respond to bacterial endotoxin or interleukin-1 beta (IL-1 beta) with increased prostaglandin E2 (PGE2) production. The effects of endotoxin persisted for up to 24 h, whereas those of IL-1 beta were maximal 4-8 h after addition. The maximum levels of PGE2 (200-350 pg/ml) were similar in all experiments, and were independent of the stimulus used. Not all tissues responded to these stimuli; those which did not had basal levels of PGE2 production of 200-350 pg/ml, which was not further increased by endotoxin or IL-1 beta. The basal production from these tissues was therefore similar to the maximal production from those tissues which responded to endotoxin or IL-1 beta. The high basal production of PGE2 was attributed to prior in vivo activation of the membranes such that PGE2 synthesis could not be further stimulated in vitro. Overnight pretreatment with aspirin decreased basal PGE2 production from these activated membranes to < 100 pg/ml/4 h during subsequent culture in aspirin-free medium. Both endotoxin and IL-1 beta increased PGE2 production from the activated aspirin-pretreated membranes during this culture time, but this was transient as after 12 h of culture basal PGE2 production rose to over 200 pg/ml despite aspirin pretreatment.