Spontaneous regression of an interhemispheric arachnoid cyst: illustrative case

BACKGROUND

Intracranial arachnoid cysts are benign collections of cerebrospinal fluid that are often asymptomatic and discovered incidentally. An interhemispheric location of these lesions is rare, with only a few such cases reported in the literature. Though spontaneous regression of arachnoid cysts has been described in other locations, to date this phenomenon has not been reported in interhemispheric fissure cysts.

OBSERVATIONS

In this report, we describe a patient with a large, multiloculated interhemispheric arachnoid cyst diagnosed on prenatal ultrasound. She did not exhibit neurologic deficits or signs of increased intracranial pressure and was observed with serial imaging. After several years of observation, imaging revealed spontaneous and progressive decrease in the cyst size.

LESSONS

We illustrate a case of regression of an interhemispheric arachnoid cyst in a pediatric patient. To our knowledge, this is the first reported case of spontaneous shrinkage of an arachnoid cyst in this location. Although the current presentation is rare, this reporting adds to the current understanding of natural history of arachnoid cysts and provides an example of radiographical improvement without intervention of a cyst located within the interhemispheric fissure.

Neurosurgery Influences and X: A Social Media Analysis

BACKGROUND

There exists a complex and ever-evolving relationship between social media and medicine. This study investigates the usage of X (formerly Twitter) among neurosurgeons and explores how virtual engagement potentially impacts this specialty.

METHODS

The researchers examined X posts from the top fifty influential neurosurgeons over 6 months. Demographics and practice information were collected. Posts were categorized into 9 predetermined coding definitions. Descriptive statistics were used to summarize user characteristics. χ2 tests and two-tailed T-tests were employed to examine patterns of posting behavior.

RESULTS

Most influencers practiced in an academic setting (89%) and 43% of them were age fifty or older. Only 15% identified as female. Cerebrovascular subspecialists accounted for 39% of the cohort. Reposting was the most popular type of posting, constituting 61% of all posts. The most common postcategory observed was "Professional Events" (31%), while "Patient Education" was the least common (0.8%). Private practice and general neurosurgeons infrequently posted about "Professional Events" (5.1%, P < 0.01 and 3.2%, P < 0.01, respectively). "Personal Thoughts" constituted the second most common category, with a notable increase among users younger than 50 (25%, P < 0.01), individuals who identified as female (62%, P < 0.01), those in private practice (69%, P < 0.01), and general neurosurgeons (86%, P < 0.01).

CONCLUSIONS

Neurosurgeons of all ages use X to advance their careers and stay updated. However, the utilization of this influential platform likely varies depending on the current practice setting and individual career goals. Neurosurgeons on X appear to have the greatest influence within an academic context, particularly when promoting professional events.

Nontraumatic symptomatic de novo arachnoid cyst in an adolescent patient treated with cystoperitoneal shunting: illustrative case

BACKGROUND

Arachnoid cysts are often congenital, asymptomatic lesions detected in the pediatric population. When seen in adults, they usually occur following trauma. De novo formation of arachnoid cysts is uncommon, with only a few instances cited in the literature and most of which occurred in the pediatric population. Treatment options for these lesions include observation, craniotomy for cyst resection, microsurgical/endoscopic fenestration, or shunting.

OBSERVATIONS

In this report, the authors describe a female patient with a de novo, symptomatic, enlarging middle cranial fossa arachnoid cyst detected at age 16 years. She was treated with the placement of a cystoperitoneal shunt. After surgery, she experienced clinical and radiological improvement.

LESSONS

We illustrate successful shunting of a de novo arachnoid cyst in a symptomatic teen patient. Although arachnoid cysts in certain intracranial locations are more likely to produce symptoms, those in the middle cranial fossa tend to be asymptomatic. To our knowledge, this is the first reported case of a symptomatic de novo arachnoid cyst located in the middle cranial fossa in a postpubertal patient. Although the current presentation is rare, the authors demonstrate an effective surgical treatment of a symptomatic, large, de novo arachnoid cyst in a postpubertal pediatric patient.

Predictors of Subsequent Intervention After Middle Meningeal Artery Embolization for Treatment of Subdural Hematoma: A Nationwide Analysis

BACKGROUND

Middle meningeal artery (MMA) embolization has recently emerged as an effective technique to treat subdural hematomas (SDHs). Studies to date have been limited, largely, to single-center studies with limited follow-up and have not assessed subsequent surgical interventions and factors associated with these interventions.

OBJECTIVE

To evaluate rates of retreatment for SDH after MMA embolization and patient-specific factors that may be important predictors for these interventions.

METHODS

Using an all-payer claims database, Mariner, patients who underwent MMA embolization between January 2010 and October 2020 after the diagnosis of SDH were identified. Rates of post-MMA embolization surgical interventions, including craniotomy and burr hole drainage, were accessed within 5 years following. Patient-specific contributors to the rates of these interventions were studied using Gaussian logistic regression models.

RESULTS

A total of 322 patients were included. Of this cohort, 55 (17.1%) required subsequent intervention within 5 years, with 36 (11.2%) receiving burr hole evacuation and 19 (5.9%) receiving craniotomy. Factor Xa inhibitor use was independently associated with subsequent interventions after MMA embolization procedures (odds ratio: 1.20 [95% CI: 1.02-1.40]). Of the other patient factors evaluated, including age, sex, comorbidity status, and use of vitamin K antagonists, antiplatelets, and factor Xa inhibitors, none were found to be significantly associated with future interventions.

CONCLUSION

Although previous literature has shown MMA embolization to be safe and successful in preventing recurrent SDH, patients undergoing this procedure still carry a risk of future interventions. Patients taking factor Xa inhibitors are at especially high risk of subsequent intervention after MMA embolization.

Extensive Symptomatic Thoracolumbar Epidural Lipomatosis Treated With Minimally Invasive Hemilaminectomies: Technical Case Report

BACKGROUND AND IMPORTANCE

Spinal epidural lipomatosis is a rare condition commonly associated with chronic corticosteroid use and obesity that involves deposition of adipose tissue in the epidural space of the spinal canal. This accumulation of adipose tissue may cause compression of the spinal cord and/or nerve roots and result in compressive symptoms such as myelopathy or radiculopathy. Spinal involvement is usually confined to either the thoracic or lumbar spine but can infrequently affect both regions. Depending on pre-existing conditions, treatment options include weight loss and discontinuation of exogenous steroid use, both of which have been shown to be effective therapeutic methods. Surgical decompression may be useful for appropriately selected patients in whom conservative therapy has failed or who experience acute neurological deterioration, although this is rarely indicated.

CLINICAL PRESENTATION

In this study, we describe a patient receiving long-term corticosteroid therapy who presented with symptomatic epidural lipomatosis that involved the thoracic and lumbar spine. She was treated with decompression by continuous T3-L5 hemilaminectomies performed through 5 small incisions of alternating laterality. After surgery, the patient experienced clinical improvement and was able to return to her baseline.

CONCLUSION

We illustrate a successful spinal decompression of extensive epidural lipomatosis through a less-invasive surgical approach using several small incisions to accomplish uninterrupted hemilaminectomies. This alternative approach to a standard continuous incision can be considered in cases of extensive spinal epidural lipomatosis in patients with multiple medical comorbidities in whom wound healing is believed to be an issue and for whom minimizing blood loss is crucial.

Use of intraoperative MRI for resection of intracranial tumors: A nationwide analysis of short-term outcomes

OBJECTIVE

Recent evidence supports the use of intraoperative MRI (iMRI) during resection of intracranial tumors due to its demonstrated efficacy and clinical benefit. Though many single-center investigations have been conducted, larger nationwide outcomes have yet to be characterized.

METHODS

We used the American College of Surgeons National Surgical Quality Improvement Program database to examine baseline characteristics and 30-day postoperative outcomes among patients undergoing craniotomy for tumor resection with and without iMRI. Comparisons between outcomes were accomplished after propensity matching using chi-square tests for categorical variables and Welch two-sample t-tests for continuous variables.

RESULTS

A total of 38,003 patients met inclusion criteria. Of this population, 54 (0.1%) received iMRI, while 37,949 (99.9%) did not receive iMRI. After propensity score matching, the resulting groups consisted of an iMRI group (n = 54) and a matched non-iMRI group (n = 54). Procedures involving iMRI were associated with significantly increased operation length compared to those without (p < 0.01). Length of hospital stay was higher in patients without iMRI, with this difference trending towards significance (p = 0.05) in the unmatched comparison. Patients undergoing craniotomy without iMRI had a higher rate of readmission (p = 0.04). There was no significant difference in occurrence of other adverse events between the two patient groups.

CONCLUSION

Despite increasing operative length, iMRI is not associated with higher infection rate and may have a clinical benefit associated with reducing readmissions and a trend towards reducing inpatient length of stay. Additional nationwide analyses including more iMRI patients would provide further insight into the strength of these findings.

Abstract WP149: Mechanical Thrombectomy For Ischemic Stroke: Evaluating Outcome Associations With Race

Introduction: Prior evidence suggests that treatment outcomes after ischemic stroke differ based on racial background. For example, two studies that queried the National Inpatient Sample (NIS) found that White patients were more likely to be discharged home compared to non-White patients after treatment with mechanical thrombectomy or IV tPA. Although these database studies provide the advantage of substantial patient numbers, the NIS is an inpatient administrative dataset lacking stroke-specific outcomes such as modified Rankin Score (mRS) and follow-up data. Nevertheless, a relationship between race and clinical outcome after thrombectomy is suggested.

Methods: We utilized the NeuroVascular Quality Initiative-Quality Outcomes Database (NVQI-QOD) to collect demographic data, clinical information, and outcome measures on ischemic stroke patients treated with mechanical thrombectomy. Univariate and multivariate analysis was conducted to evaluate the relationship between race and outcomes such as mRS at discharge (0-2 vs. 3-6), discharge disposition, and 90-day mRS (0-2 vs. 3-6). Race was included in multivariate modeling as it was our predictor variable of interest. P<0.05 was used for statistical significance.

Results: A total of 3,597 patients were included. Of the entire cohort, 15.8% of patients were Black. On univariate analysis, Black race was significantly associated with younger age at treatment, CHF, hypertension, diabetes, prior stroke, being a current smoker, and higher baseline NIHSS (16.4 for Black compared to 15.8 for non-Black, p=0.044). Non-Black race was significantly associated with atrial fibrillation and hyperlipidemia at baseline. On both univariate and multivariate analysis, Black race was not significantly associated with discharge mRS, discharge to home, or 90-day mRS (p>0.3 for all).

Conclusions: In conclusion, though Black race seems to be associated with several comorbidities prior to ischemic stroke, we did not find a significant association between Black race and clinical outcome after mechanical thrombectomy.

Sex Differences in Cerebral Aneurysms and Subarachnoid Hemorrhage

Sex differences in cerebral aneurysm occurrence and characteristics have been well described. Although sex differences in outcomes following ischemic stroke have been identified, the effect of sex on outcomes following hemorrhagic stroke, and in particular, aneurysm treatment has been less studied. We describe the current state of knowledge regarding the impact of sex on treatment and outcomes of cerebral aneurysms. Although prior studies suggest that aneurysm prevalence and progression may be related to sex, we did not find clear evidence that outcomes following subarachnoid hemorrhage vary based on sex. Last, we identify areas for future research that could enhance understanding of the role sex plays in this context.

Cannabis Abuse and Perioperative Complications After Treatment of Intracranial Aneurysms: A Nationwide Analysis

OBJECTIVE

In the present retrospective cohort analysis, we examined the differences in baseline characteristics and peri- and postoperative outcomes stratified by 3 groups: cannabis abuse or dependence versus none, surgical versus endovascular treatment, and unruptured and ruptured intracranial aneurysms.

METHODS

A study population of 26,868 patients was defined using the 2009-2016 National Inpatient Sample database. The baseline characteristics were compared between the cannabis and no-cannabis groups, and the traits that differed significantly were factored into the multivariate analysis using 1:1 propensity score matching. The matched groups were analyzed to compare the cannabis and no-cannabis cohorts for the following endpoints: mortality, length of stay, discharge disposition, total hospital charges, and several peri- and postoperative outcomes.

RESULTS

In the surgically and endovascularly treated groups for unruptured intracranial aneurysms, those in the cannabis group were more likely to be male and younger and to smoke tobacco than were those in the no-cannabis group. After matching, no significant endpoint differences were noted. Similarly, in the surgically and endovascularly treated ruptured aneurysm groups, those in the cannabis group were more likely to be male and younger and to smoke tobacco. After matching, the cannabis group within the endovascular treatment group had had a longer length of stay and were more likely to have developed any hydrocephalus, obstructive hydrocephalus, sepsis, and acute kidney injury. Those in the cannabis group who had undergone surgery were more likely to have developed any hydrocephalus, specifically, communicating hydrocephalus.

CONCLUSIONS

The cannabis group with ruptured intracranial aneurysms was more likely to experience certain adverse outcomes after surgical or endovascular treatment compared with the no-cannabis group. However, such was not the case for cannabis abusers treated for unruptured aneurysms.

Inpatient outcomes of posterior fossa decompression with or without duraplasty for Chiari malformation type I

OBJECTIVE

Chiari malformation type 1 (CM-1) is a congenital neurologic condition in which the cerebellar tonsils herniate below the foramen magnum, resulting in symptoms such as headache and neck pain. Two common surgical treatment approaches are posterior fossa decompression with (PFDD) and without duraplasty (PFD). Previous single-center studies have demonstrated increased neurologic complications after PFDD compared to PFD. The goal of this study is to determine differences in inpatient complications and hospitalization data among patients treated with these surgical techniques using a nationwide sample.

METHODS

The National Inpatient Sample (NIS) was queried for years 2012-2015 for all patients with a primary diagnosis of CM-1 who underwent PFD or PFDD. Differences in baseline demographics and comorbidities were accounted for in subsequent analysis using propensity score matching. Hospitalization measures and inpatient complications of the two cohorts were compared using Chi-squared tests and t-tests when appropriate.

RESULTS

A total of 2395 patients with CM-1 were included in this study, with 750 (31.3%) undergoing PFD and 1645 (68.7%) undergoing PFDD. PFDD was associated with higher total hospital costs than PFD. There were no significant differences in other hospitalization or discharge data, non-neurologic complications, or CNS complications (CSF leak, pseudomeningocele, abscess, meningitis, stroke) between the two surgical groups.

CONCLUSIONS

This study represents the largest national analysis to date of adult CM-1 patients undergoing PFD or PFDD. Our findings suggest that whether the decision is made to perform the less invasive PFD or more invasive PFDD, inpatient complications and hospitalization data will not significantly differ.

Disparities in the symptomatic presentation of Moyamoya disease in the United States: A nationwide all-payer analysis

BACKGROUND

Moyamoya disease is a chronic occlusive cerebrovascular disease that can present with either hemorrhagic or ischemic symptoms. The objective of this study was to evaluate whether the symptomatology of Moyamoya disease differs according to patient demographic groups.

METHODS

In this study, we used the Nationwide Inpatient Sample (NIS) to investigate differences in the presentation of Moyamoya disease by age group, gender, and ethnicity from 2012 to 2016. After propensity score matching was utilized to control for overall comorbidity, the matched cohorts for each symptomatology were compared using a Chi-square test with respect to the potential risk factors of interest (i.e. age, sex, ethnicity) in order to generate multivariate reported P-values.

RESULTS

A total of 4,474 patients met inclusion criteria. Patients presenting with ischemic stroke were more likely to be 65 years and older (p < 0.001); patients presenting with intracranial hemorrhage (ICH) were more likely to be 65 years and older (p < 0.001), male (p = 0.027), and Asian (p = 0.007); those presenting with seizure were more likely to be less than 10 years old (p = 0.002) and African American (p < 0.001); and those presenting with headache were more likely to be between 10 and 19 years old (p = 0.008).

CONCLUSIONS

Our findings demonstrate that the distinct presentations of Moyamoya are associated with patient age, gender, and race. This is the largest study of its kind and adds to the collective understanding of this rare but life-threatening condition.

Revision Discectomy with or without Fusion for the Treatment of Recurrent Lumbar Disc Herniation: A Nationwide Analysis of Risk Profiles and Short-Term Outcomes

OBJECTIVE

We compared the demographics, risk factors, and complications for adult patients with recurrent lumbar disc herniation (RLDH) undergoing revision discectomy with or without concurrent fusion.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients who had undergone revision discectomy with or without simultaneous fusion. The demographic variables and various peri- and postoperative complications were compared between these 2 patient groups.

RESULTS

A total of 6901 discectomy patients were included in the present study, of whom 2996 (43.4%) had undergone revision discectomy with fusion and 3905 (56.6%) had undergone revision discectomy alone. The revision discectomy with fusion group was significantly more likely to be older, female, and White or Black and to have a higher average body mass index than was the revision discectomy alone group. The discectomy with fusion group had longer hospital lengths of stay and was more likely to have a diagnosis of hypertension, insulin-dependent and non-insulin-dependent diabetes, and chronic obstructive pulmonary disease. In addition, the patients who had undergone discectomy with fusion were significantly more likely to develop pneumonia, require ventilation for >48 hours, require a blood transfusion, and to develop urinary tract infection, myocardial infarction, deep vein thrombosis, or pulmonary embolism compared with the patients who had undergone revision discectomy only.

CONCLUSIONS

Our findings reveal that older patients with more comorbidities were more likely to undergo revision discectomy with fusion. Also, this surgical group experienced more adverse events after their procedure compared with the revision discectomy only group.

Gunshot wounds to the head: racial disparities in inpatient management and outcomes

OBJECTIVE

Several studies have indicated that racial disparities may exist in the management and outcomes of acute trauma care. One segment of trauma care that has not been as extensively investigated, however, is that of cranial trauma care. The goal of this study was to determine whether significant differences exist among racial and ethnic groups in various measures of inpatient management and outcomes after gunshot wounds to the head (GWH).

METHODS

In this study, the authors used the Nationwide (National) Inpatient Sample (NIS) to investigate all-cause mortality, receipt of surgery, days from admission to initial intervention, discharge disposition, length of hospital stay, and total hospital charges of those with GWH from 2012 to 2016. A 1:1 propensity score–matched analysis was conducted to evaluate the effect of race on these endpoints, while controlling for baseline demographics and comorbidities.

RESULTS

A total of 333 patients met the inclusion and exclusion criteria: 148 (44.44%) white/Caucasian, 123 (36.94%) black/African American, 54 (16.22%) Hispanic/Latinx, and 8 (2.40%) Asian. African American patients were sent to immediate care and rehabilitation significantly less often than Caucasian patients (RR 0.17 [95% CI 0.04–0.71]). There were no significant differences in mortality, length of stay, rates of surgical intervention, or total hospital charges among any of the racial groups.

CONCLUSIONS

The authors’ findings suggest that racial disparities in inpatient cranial trauma care and outcomes may not be as prevalent as previously thought. In fact, the disparities seen were only in disposition. More research is needed to further elucidate and address disparities within this population, particularly those that may exist prior to, and after, hospitalization.

Crystallization and preliminary X-ray analysis of the NADP-specific glutamate dehydrogenase from Neurospora crassa

The NADP-linked glutamate dehydrogenase from Neurospora crassa has been crystallized by the hanging-drop method of vapour diffusion in the presence of 0.1 M glutamate. The crystals are trigonal and are in space group P3(1)21 with unit-cell dimensions of a = b = 196.6, c = 102.0 A and with a trimer in the asymmetric unit. A full structure determination of this enzyme will lead to an understanding of the molecular basis of inter-allelic complementation observed with hybrid hexamers of naturally occurring mutants.

Hydrogen peroxide mediates vascular cell adhesion molecule-1 expression from interleukin-18-activated hepatic sinusoidal endothelium: implications for circulating cancer cell arrest in the murine liver

The mechanism of intrasinusoidal arrest of circulating cancer cells, which is a critical step in liver metastasis, appears to be facilitated by tumor-derived proinflammatory factors that increase sinusoidal cell adhesion receptors for cancer cells. However, how this prometastatic microenvironment is up-regulated remains unknown. Using intrasplenically injected B16 melanoma (B16M) cells, we show that the expression of vascular cell adhesion molecule-1 (VCAM-1) significantly increased in hepatic sinusoidal endothelium (HSE) cells over physiologic baseline within the first 24 hours of metastatic cancer cell infiltration in the liver. This correlated with increased in vitro adhesion of B16M cells to HSE cells isolated from B16M cell-injected mice. In vivo VCAM-1 blockade with specific antibodies before B16M cell injection decreased sinusoidal retention of luciferase-transfected B16M cells by 85%, and metastasis development by 75%, indicating that VCAM-1 expression on tumor-activated HSE cells had a prometastatic contribution. Because VCAM-1 expression is oxidative stress-inducible, recombinant catalase was in vivo administered, resulting in a complete abrogation of both VCAM-1 expression and B16M cell adhesion increases in HSE cells isolated from B16M cell-injected mice. Catalase also abrogated the proadhesive response of HSE cells to B16M-conditioned medium (B16M-CM) in vitro, although this did not affect the concomitant release of major proinflammatory cytokines by HSE cells. HSE cells treated with B16M-CM released interleukin (IL)-18 via tumor necrosis factor-alpha (TNF-alpha)-dependent IL-1beta in vitro. In turn, H(2)O(2) production from B16M-CM-treated HSE cells was regulated by IL-18. Thus, liver-infiltrating B16M cells activated their adhesion to HSE through a sequential process involving TNF-alpha-dependent IL-1beta, which induced IL-18 to up-regulate VCAM-1 via H(2)O(2). The pivotal position of H(2)O(2) was further supported by the fact that incubation of HSE cells with nontoxic concentrations of H(2)O(2) directly enhanced VCAM-1-dependent B16M cell adhesion in vitro without proinflammatory cytokine mediation, which emphasizes the key role of oxidative stress in the pathogenesis of liver inflammation and metastasis.

Differential activities of the SoxR protein of Escherichia coli: SoxS is not required for gene activation under iron deprivation

When Escherichia coli cells are under superoxide stress, proteins SoxR and SoxS, acting sequentially, control the expression of a set of repair and defense genes. One of these genes, fumC, encoding fumarase C, was reported to be also activated by iron deprivation in a soxRS-dependent manner. However, the same condition failed to induce the expression of a soxS'::lacZ fusion. The expression of acnA (aconitase A) is also activated by SoxR alone when under iron deprivation, but not of sodA (Mn-superoxide-dismutase). SoxR completely inhibited the migration of a DNA fragment containing the promoter region of fumC, in gel-shift experiments. SoxR might bind to a different region than SoxS within the fumC promoter, or an unknown intermediate other than SoxS might be acting. It is possible that the regulatory role of SoxR is more complex than previously considered.

The Neurospora am gene and NADP-specific glutamate dehydrogenase: mutational sequence changes and functional effects--more mutants and a summary

A further series of mutant am alleles, encoding potentially active NADP-specific glutamate dehydrogenase (GDH) and capable of complementation in heterocaryons, have been characterized with respect to both GDH properties and DNA sequence changes. Several mutants previously studied, and some of their same-site or second-site revertants, have also been sequenced for the first time. We present a summary of what is known of the properties of all am mutants that have been defined at the sequence level.

[New blood transfusion partners in France]

The French Blood Agency, created in 1993, controls all aspects of the blood transfusion system. It is responsible for restructuring the blood transfusion system and for Good Manufacturing Practices. All incidences are reported to the blood monitoring system which also obtains further descriptions of such incidents. Blood transfusion policies have been modified to include monitoring of blood-associated morbidity. Successive reforms have led to the establishment of a new public system for blood transfusion. New structures and more formal designation of responsibilities are needed. The function of these new structures is to better control transfusion activities and prevent unknown risk.

IL-18 regulates IL-1beta-dependent hepatic melanoma metastasis via vascular cell adhesion molecule-1

Proinflammatory cytokines, including IL-1beta and tumor necrosis factor-alpha (TNF-alpha), promote cancer cell adhesion and liver metastases by up-regulating the expression of vascular cell adhesion molecule-1 (VCAM-1) on hepatic sinusoidal endothelium (HSE). In this study, hepatic metastasis after intrasplenically injected mouse B16 melanoma (B16M) cells was reduced 84-95% in mice with null mutations for either IL-1beta or the IL-1beta-converting enzyme (ICE, caspase-1) compared with wild-type mice. On day 12, 47% of wild-type mice were dead compared with 19% of either IL-1beta or ICE-deficient mice. In vitro, conditioned medium from B16M cells (B16M-CM) induced the release of TNF-alpha and IL-1beta from cultures of primary murine HSE. The effect of B16M-CM on HSE resulted in increased numbers of B16M cells adhering to HSE, which was completely abrogated by a specific inhibitor of ICE, anti-IL-18 or IL-18-binding protein. Exogenous IL-18 added to HSE also increased the number of adhering melanoma cells; however, this was not affected by IL-1 receptor blockade or TNF neutralization but rather by anti-VCAM-1. These results demonstrate a role for IL-1beta and IL-18 in the development of hepatic metastases of B16M in vivo. In vitro, soluble products from B16M cells stimulate HSE to sequentially release TNF-alpha, IL-1beta, and IL-18. The IL-18 cytokine increases expression of VCAM-1 and the adherence of melanoma cells.

Mannose receptor-mediated endothelial cell activation contributes to B16 melanoma cell adhesion and metastasis in liver

The role of mannose receptors from hepatic sinusoidal endothelium (HSE) in liver colonization by B16 melanoma (B16M) cells was studied. The expression of high mannose-type oligosaccharides on the surface of B16M cells was enhanced by in vitro treatment with 1-deoximannojirimycin (1-DMM). There was a significant (P < 0.01) enhancement of hepatic metastasis when B16M cells were 1-DMM-treated before being intrasplenically injected into C57BL/6J mice. Intraperitoneal administration of 5 mg/kg recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) inhibited the 1-DMM-induced enhancement of metastasis. Expression of high mannose-type oligosaccharides on the surface of 1-DMM-treated B16M cells and their in vitro adhesion to the HSE was significantly correlated (R = 0.82). The addition of either 100 microg/ml mannan or paraformaldehyde (PFA)-fixed 1-DMM-treated B16M cells to cultured HSE for a period of 12 h significantly (P < 0.01) increased the release of IL-1beta from the HSE compared to that liberated by the HSE incubated with either basal medium or PFA-fixed untreated B16M cells. The same HSE treatments also significantly (P < 0.01) increased the degree of adhesion of other B16M cells to HSE, being abrogated by anti-mouse vascular cell adhesion molecule-1 (VCAM-1) antibodies. The conditioned media from HSE cultures, activated by PFA-fixed, 1-DMM-treated B16M cells significantly (P < 0.01) increased B16M cell proliferation when compared to conditioned media from HSE cultures incubated with PFA-fixed, untreated B16M cells. Thus, 1-DMM treatment of B16M cells enhanced the development of hepatic metastasis by IL-1-dependent mechanisms. The mechanism is consistent with in vitro mannose receptor-mediated melanoma cell attachment to the HSE, which subsequently upregulates IL-1beta release, VCAM-1-dependent adherence, and melanoma growth factor(s) release by HSE.

Mercury induces multiple antibiotic resistance in Escherichia coli through activation of SoxR, a redox-sensing regulatory protein

Sub-inhibitory mercury concentrations are capable of partially activating SoxR, as shown by the augmented expression of a soxS'::lacZ fusion, and a diminished sensitivity to antibiotics caused by mercury treatment. Mercury may elevate the intracellular concentration of superoxide or perhaps act as a putative metal ligand for SoxR.

Cloning of a novel neuronal nitric oxide synthase expressed in penis and lower urinary tract

The neuronal nitric oxide synthase (nNOS) is the main NOS isoform in the urogenital tract catalyzing the synthesis of nitric oxide, the mediator of penile erection and presumably an important factor in the control of urinary voiding. We have cloned from the rat penile corpora cavernosa a cDNA coding for a novel nNOS differing from the cerebellar nNOS by the presence of a 102 nucleotides stretch and other features. This new species is the only nNOS mRNA expressed in the rat penis, urethra, prostate, and skeletal muscle, coexists with the cerebellar nNOS in the pelvic plexus and bladder, and is detectable in the cerebellum. The novel insert is present in human penile RNA and is transcribed from intron 16. The features and distribution of the penile nNOS suggest that it is may be regulated differentially from the cerebellar nNOS.

Prolactin response to dopamine and valproate administration in breast cancer patients

There is only indirect evidence available at present to suggest the role of prolactin (PRL) in either the promotion or progression of human breast cancer. In order to determine if dopaminergic and GABAergic regulation of PRL are similar in breast cancer patients, we studied 2 groups of premenopausal women with no evident endocrine alteration: 1) control subjects (C); and 2) breast cancer patients (CA). Basal PRL levels were measured and their response to dopamine (DA) infusion (0.004 micrograms/kg/min) and valproate administration (400 mg/p.o.). The mean of percentage inhibition by DA in C (n = 6) was significantly higher than in CA (n = 11) at 180 min; P less than 0.025. On the other hand, group C (n = 8) responded to valproate with maximal inhibition at 180 min; in the CA group (n = 8) no inhibition was observed; P less than 0.0025.

The relation of angiotensin-converting enzyme to the pregnancy-induced hypertension-preeclampsia syndrome

Angiotensin-converting enzyme, the polypeptide that converts angiotensin I to angiotensin II, was measured in the serum of 114 pregnant women who had normal blood pressure, pregnancy-induced hypertension-preeclampsia, and chronic hypertension with or without pregnancy-induced hypertension. Angiotensin-converting enzyme levels were unrelated to weeks of gestation. The angiotensin-converting enzyme levels were similar in normotensive women (21.1 +/- 6.9 units/ml), women with chronic hypertension without pregnancy-induced hypertension (23.1 +/- 2.7 units/ml), and patients with pregnancy-induced hypertension where magnesium sulfate (22.6 +/- 8.7 units/ml) had been administered prior to angiotensin-converting enzyme assay, but these values were significantly less than those in patients with pregnancy-induced hypertension with no magnesium sulfate (29.1 +/- 6.5 units/ml) therapy and in women with chronic hypertension with superimposed pregnancy-induced hypertension (30.7 +/- 4.4 units/ml) (p less than 0.005). Maternal venous and umbilical venous and arterial angiotensin-converting enzyme levels were as follows: The maternal venous level was less than the cord venous level and greater than the cord arterial value. Neither neonatal size nor twin gestation influenced the angiotensin-converting enzyme levels. Patients with diabetes mellitus had variable angiotensin-converting enzyme values regardless of the status of the blood pressure. The physiologic theories of blood pressure control in pregnant women are discussed in relation to the renin-angiotensin, bradykinin, and prostaglandin systems.

Prostaglandin E release by rat medial basal hypothalamus in vitro. Inhibition by melatonin at submicromolar concentrations

Melatonin depressed PGE release by rat medial basal hypothalamus (MBH) in vitro at concentrations 10(-8) M or greater. The two-fold increase in PGE release induced by adding 10(-4) M norepinephrine to MBH explants was also impaired by melatonin at micromolar or greater concentrations. These data support the view that melatonin is a physiological inhibitor of PG synthesis in MBH.