Current Treatment Approaches and Global Consensus Guidelines for Brain Metastases in Melanoma

Background

Up to 60% of melanoma patients develop melanoma brain metastases (MBM), which traditionally have a poor diagnosis. Current treatment strategies include immunotherapies (IO), targeted therapies (TT), and stereotactic radiosurgery (SRS), but there is considerable heterogeneity across worldwide consensus guidelines.

Objective

To summarize current treatments and compare worldwide guidelines for the treatment of MBM.

Methods

Review of global consensus treatment guidelines for MBM patients.

Results

Substantial evidence supported that concurrent IO or TT plus SRS improves progression-free survival (PFS) and overall survival (OS). Guidelines are inconsistent with regards to recommendations for surgical resection of MBM, since surgical resection of symptomatic lesions alleviates neurological symptoms but does not improve OS. Whole-brain radiation therapy is not recommended by all guidelines due to negative effects on neurocognition but can be offered in rare palliative scenarios.

Conclusion

Worldwide consensus guidelines consistently recommend up-front combination IO or TT with or without SRS for the treatment of MBM.

Underestimation of Pupil Size by Critical Care and Neurosurgical Nurses

BACKGROUND

Early detection of pupillary changes in patients with head injuries can alert the care team to increasing intracranial pressure. Previous research has shown inconsistencies in pupil measurement that are most likely due to the subjective nature of measuring pupils without the assistance of technology.

OBJECTIVES

To evaluate nurses' abilities to assess pupil diameter accurately and detect unequal pupils.

METHODS

In a 3-part study, the accuracy of critical care and neurosurgical nurses' assessments of pupils was determined. The study included assessment of drawings of eyes with an iris and pupil, examination of photographs of human eyes, and bedside examination of patients with a head injury.

RESULTS

Subjective assessments of pupil diameter and symmetry were not accurate. Across all phases of the study, pupil diameters were underestimated and the rate of error increased as pupil size increased. Nurses also failed to detect anisocoria and misidentified pupil reactivity. In addition, nearly all nurses relied on subjective estimation, even when tools were available.

CONCLUSIONS

Critical care and neurosurgical nurses underestimated pupil size, were unable to detect anisocoria, and incorrectly assessed pupil reactivity. Standardized use of pupil assessment tools such as a pupillometer is necessary to increase accuracy and consistency in pupil measurement and to potentially contribute to earlier detection of subtle changes in pupils. If pupillary changes are identified early, diagnostic and treatment intervention can be delivered in a more timely and effective manner.

Exploring the diversity and metabolic potential of actinomycetes from temperate marine sediments from Newfoundland, Canada

Marine sediments from Newfoundland, Canada were explored for biotechnologically promising Actinobacteria using culture-independent and culture-dependent approaches. Culture-independent pyrosequencing analyses uncovered significant actinobacterial diversity (H'-2.45 to 3.76), although the taxonomic diversity of biotechnologically important actinomycetes could not be fully elucidated due to limited sampling depth. Assessment of culturable actinomycete diversity resulted in the isolation of 360 actinomycetes representing 59 operational taxonomic units, the majority of which (94 %) were Streptomyces. The biotechnological potential of actinomycetes from NL sediments was assessed by bioactivity and metabolomics-based screening of 32 representative isolates. Bioactivity was exhibited by 41 % of isolates, while 11 % exhibited unique chemical signatures in metabolomics screening. Chemical analysis of two isolates resulted in the isolation of the cytotoxic metabolite 1-isopentadecanoyl-3β-D-glucopyranosyl-X-glycerol from Actinoalloteichus sp. 2L868 and sungsanpin from Streptomyces sp. 8LB7. These results demonstrate the potential for the discovery of novel bioactive metabolites from actinomycetes isolated from Atlantic Canadian marine sediments.

Refining the Indications for the Addition of Orbital Osteotomy during Anterior Cranial Base Approaches: Morphometric and Radiologic Study of the Anterior Cranial Base Osteology

Objectives In anatomic and radiologic morphometric studies, we examine a predictive method, based on preoperative imaging of the anterior cranial base, to define when addition of orbital osteotomy is warranted.

Design Anatomic and radiographic study.

Setting In 100 dry skulls, measurements in the anterior cranial fossa included three lines and two angles based on computerized tomography (CT) scans taken in situ and validated using frameless stereotactic navigation. The medial angle (coronal plane) was the intersection between the highest point of both orbits and the midpoint between the two frontoethmoidal sutures to each orbital roof high point. The oblique angle (sagittal plane) was the intersection at the midpoint of the limbus sphenoidale.

Results No identifiable morphometric patterns were found for our classification of anterior fossae; the two-tailed distribution pattern was similar for all skulls, disproving the hypothetical correlation between visual appearance and morphometry. Orbital heights (range: 6.6–18.7 mm) showed a linear relationship with medial and oblique angles, and they had a linear distribution relative to angular increments. Orbital heights > 11 mm were associated with angles ≥ 20 degrees and more likely to benefit from orbitotomy.

Conclusion Preoperative CT measurement of orbital height appears feasible for predicting when orbitotomy is needed, and it warrants further testing.

Anatomic variation of the optic strut: classification schema, radiologic evaluation, and surgical relevance

Objective Anatomic variability of the optic strut in location, orientation, and dimensions is relevant in approaching ophthalmic artery aneurysms and tumors of the anterior cavernous sinus, medial sphenoid wing, and optic canal. Methods In 84 dry human skulls, imaging studies were performed (64-slice computed tomography [CT] scanner, axial view, aligned with the zygomatic arch). Optic strut location related to the prechiasmatic sulcus was classified as presulcal, sulcal, postsulcal, and asymmetric. Morphometric analysis was performed. Results The optic strut was presulcal in 11.9% specimens (posteromedial margin bilaterally anterior to limbus sphenoidale), sulcal in 44% (posteromedial part adjacent to the sulcus's anterior two thirds bilaterally), postsulcal in 29.8% (posteromedial margin posterior to the sulcus's anterior two thirds), and asymmetric (left/right) in 14.3%. Optic strut length, width, and thickness measured 6.54 ± 1.69 mm, 4.23 ± 0.69 mm, and 3.01 ± 0.79 mm, respectively. Optic canal diameter was 5.14 ± 0.47 mm anteriorly and 4.79 ± 0.64 mm posteriorly. Angulation was flat (>45 degrees) in 13% or acute (<45 degrees) in 87% specimens. Conclusions Anatomical variations in the optic strut are significant in planning for anterior clinoidectomy and optic-canal decompression. Our optic strut classification considers these variations relative to the prechiasmatic sulcus on preoperative imaging.

Assessment of diabetic macrovascular complications: a prediabetes model

Prediabetes is a condition that requires early intervention against diabetic macrovascular complications. This study aims to assess whether or not the likelihood of diabetes macrovascular complications occurring in prediabetes can be better estimated by a model combining a set of conventional and emerging biomarkers, with a view to improving cardiovascular disease (CVD) screening in individuals with elevated blood glucose levels associated with prediabetes. A total of 71 participants (female/male: 32/39) were divided into two groups - the prediabetic group (preDM: n=34) and the diabetic with cardiovascular complications group (DM+CVD: n=37). Blood glucose level (BGL), blood pressure (BP), total cholesterol (TC), high-density lipoprotein (HDL) and TC:HDL ratio, erythrocyte oxidative stress (as determined by reduced glutathione [GSH], malondialdehyde and methaemoglobin levels) and vascular events (D-dimer, homocysteine and whole blood viscosity) were measured. Statistical analysis was by binomial logistic regression modelling with forward likelihood ratio step procedures. A combination of BGL, BP, erythrocyte GSH and TC gave the best group identifications, with 28/34 (82.4%) and 29/37 (78.4%) members correctly identified in the preDM and DM + CVD groups, respectively. Six of the 34 (17.6%) prediabetes individuals were logistically identified as having diabetic macrovascular complications, but clinically did not qualify for CVD intervention under current screening models. The authors propose that a combination of BGL, BP, erythrocyte GSH and TC can provide a clinically acceptable standard for identifying CVD risk in individuals with prediabetes. This model provides a tool for early identification and targeted intervention in individuals with subclinical diabetes who are at risk of CVD.

Maximizing the extent of tumor resection during transsphenoidal surgery for pituitary macroadenomas: can endoscopy replace intraoperative magnetic resonance imaging?

OBJECT

Endoscopic approaches to pituitary tumors have become an effective alternative to traditional microscopic transsphenoidal approaches. Despite a proven potential to decrease unexpected residual tumor, intraoperative MR (iMR) imaging is infrequently used even in the few operating environments in which such technology is available. Its use is prohibitive because of its cost, increased complexity, and longer operative times. The authors assessed the potential of intrasellar endoscopy to replace the need for iMR imaging without sacrificing the maximum extent of resection.

METHODS

In this retrospective study, 27 consecutive patients underwent fully endoscopic resection of pituitary macroadenomas. Intrasellar endoscopy was used to determine the presence of residual tumor within the sella turcica and tumor cavity. Intraoperative MR imaging was used to identify rates of unexpected residual tumor and the need for further tumor resection.

RESULTS

Intraoperative estimates of the extent of tumor resection were correct in 23 patients (85%). Of 4 patients with unacceptable tumor residuals, 3 underwent further tumor resection. After iMR imaging, the rate of successful completion of the planned extent of resection increased to 26 patients (96%). Rates of both endocrinopathy reversal and postoperative complications were consistent with previously published results for microscopic and endoscopic resection techniques.

CONCLUSIONS

The findings in this study provided quantitative evidence that intrasellar endoscopy has significant promise for maximizing the extent of tumor resection and is a useful adjunct to surgical approaches to pituitary tumors, particularly when iMR imaging is unavailable. A larger prospective study on the extent of resection following endoscopic transsphenoidal surgery would strengthen these findings.

Oxidative damage indices for the assessment of subclinical diabetic macrovascular complications

Subclinical cardiovascular disease (SCVD), including complications in diabetes, is associated with oxidative damage and precedes future cardiovascular disease (CVD). Hence, assessment and management of oxidative damage is imperative. This study investigates biomarkers associated with CVD, diabetes and oxidative stress in order to determine a set of indices that could be useful to assess oxidative damage in diabetic macrovascular pathogenesis. A total of 266 participants were selected and divided into seven groups (control, family history of diabetes, prediabetes, prediabetes with CVD, diabetes mellitus [DM], DM+CVD and CVD) based on clinical history/status. Blood glucose (BG) level, erythrocyte glutathione (GSH), malondialdehyde, methaemoglobin, D-dimer, homocysteine, blood viscosity and cholesterol profile were determined. Factorial MANOVA and independent univariate analyses were performed. Prevalence of significant biomarkers was assessed following a 3.5-year retrospective study. Multivariate analysis showed statistically significant differences between groups (P < 0.0001) with post hoc tests identifying a statistically significant association for BG level (P < 0.0001), GSH (P < 0.0001), D-dimer (P < 0.02) and total cholesterol (P < 0.0001). Of the subjects who showed hyperglycaemia-associated progression in clinical and biochemistry status, 89% had low-level GSH and 44% had high-level D-dimer. Four individuals exhibited prediabetic status at some stage and would qualify for macrovascular disease intervention. The results of this study suggest that BG level, D-dimer, GSH and total cholesterol contribute significantly to a diabetic oxidative damage panel of markers that could assist in evidence-based pharmacological intervention with anti-aggregation and/or antioxidant agents against future CVD in diabetes.

DELAYED EXTRUSION OF HYDROXYAPATITE CEMENT AFTER TRANSPETROSAL RECONSTRUCTION

OBJECTIVE

Use of hydroxyapatite cement has been advocated for closure of transpetrosal defects to decrease the incidence of cerebrospinal fluid leaks. We previously identified delayed extrusion of this cement as a significant complication associated with this closure technique and now update our long-term experience.

METHODS

In our retrospective review, we identified 1231 patients who underwent transpetrosal procedures by our multidisciplinary cranial base team between 1984 and 2005. Of the subgroup of 177 patients who had hydroxyapatite cement used during the closure of the procedure, 13 patients (7.3%) experienced delayed extrusion of hydroxyapatite cement.

RESULTS

Extrusion occurred in 3 patients within 12 months and in 10 patients within 68 to 140 months. Twelve patients presented with draining fistulae and concomitant Staphylococcus aureus infection; 1 patient presented asymptomatically with a large temporal lobe abscess identified on surveillance magnetic resonance imaging. All 13 patients underwent reoperation, including 1 who underwent a second procedure.

CONCLUSION

Delayed extrusion of hydroxyapatite cement resulted in significant morbidity to our patients and often presented in an indolent manner. We recommend serial examination and imaging studies in patients who have had transpetrosal closures with hydroxyapatite cement. Because of the complication rates associated with hydroxyapatite cement, we have discontinued its use.

Osteoarthritis. A primary care approach for physicians in 2000 and beyond

Osteoarthritis is one of the most common disorders presented to the primary care physician in the over 50 years age group in the Kingdom of Saudi Arabia. The diagnosis is made by history, typical x-ray findings and non-contributory laboratory investigations. The understanding of the pathogenesis of the condition is undergoing change. The development of osteoarthritis is dependent on age, sex, genetic predisposition, and previous trauma to the joint and abnormal mechanical forces caused primarily by obesity. Biochemically, there is an imbalance in the enzymes of cartilage degradation and cartilage regeneration. Management in 2000 focuses on patient education, appropriate exercise, relief of pain through judicious combination of capsaicin cream, acetaminophen in appropriate dose, and nonsteroidal anti-inflammatory drug therapy. The latter is undergoing revolutionary change with the introduction of the Coxiella-2 specific inhibitors, Rofecoxib and Celecoxib in the autumn of 2000 to the Kingdom. With these agents the primary care physician has an effective analgesic therapy, once a day dosing and a dramatic reduction in nonsteroidal anti-inflammatory drug gastropathy across all groups of patients. Finally, when the conservative management by the primary care physician is of benefit no longer, judicious referral to an experienced Orthopedic Surgeon for the modern surgical approaches should be given.

Purification and characterization of the fatty acid synthase from Bugula neritina

The fatty acid synthase from Bugula neritina has been purified 100-fold using ammonium sulfate precipitation, ion-exchange and size exclusion chromatography. The purified enzyme has a molecular weight of approximately 382,000 Da, as judged by gel filtration. Polyacrylamide gel electrophoresis under denaturing conditions in the presence of SDS revealed one major protein band of approximately 190,000 Da suggesting that the enzyme is a homodimer. The size of the enzyme, together with the observation that the FAS activity is independent of the concentration of acyl carrier protein, indicate that the FAS from Bugula neritina is a type I. A detailed analysis of the products of the purified FAS indicated that palmitic acid is the primary product and longer chain fatty acids are not produced.

In vivo and in vitro investigations into the biosynthetic relatedness of the pseudopterosins

[formula: see text] Both in vivo and in vitro techniques have been developed to test putative intermediates in the biosynthetic pathway to the pseudopterosins, antiinflammatory compounds isolated from Pseudopterogorgia elisabethae. Furthermore, specific activity data we have obtained indicate that pseudopterosin A is a precursor to pseudopterosins B, C, and D. We conclude that in the biosynthesis xylose is attached to the diterpene skeleton to produce pseudopterosin A and is then aceylated to form pseudopterosins B-D.

Identification and biosynthetic origins of sterols in the marine bryozoan bugula neritina

The sterols of Bugula neritina have been isolated and characterized spectroscopically. Cholesterol was found to be the predominant sterol with C28, C29, and C30 sterols recovered as minor components. In vivo biosynthetic experiments revealed that cholesterol is the only sterol produced by de novo biosynthesis, indicating that the other sterols are of dietary origin. Further, biosynthetic experiments using in vitro techniques indicated that 24-alkylated sterols (4, 5, 7, and 8) are produced by alkylation of dietary sterols, while others are exclusively of dietary origin.

An enzyme-based formaldehyde assay and its utility in a sponge sterol biosynthetic pathway

An enzyme-based assay has been developed and utilized to confirm the production of formaldehyde in the dealkylation of sterol side chains in a marine sponge. The enzyme used in the assay, formaldehyde dehydrogenase, is NAD+ dependent, and the assay measures the production of NADH by determining the increase in fluorescence at 460 nm.

The effects of postoperative continuous passive motion on peripheral nerve repair and regeneration. An experimental investigation in rabbits

The effects of continuous passive motion (CPM) on nerve regeneration following nerve repair were investigated. In 26 rabbits, the medial popliteal nerve was transected and microsurgically repaired. Half of the animals were treated with cast immobilization and the rest with 70 degrees arc CPM. Both treatments were discontinued on day 14. After sacrifice on day 100, no animal showed separation at the suture line. Mean nerve conduction velocity was slightly slower in the CPM than in the immobilization group. Mean fibre density was also slightly less in the CPM group but the difference was not significant. Mean fibre diameters, fibre diameter distributions, and soleus-muscle wet weights were similar in the two groups.

Preclinical pharmacology of the natural product anticancer agent bryostatin 1, an activator of protein kinase C

Bryostatin 1, a natural product anticancer agent isolated from a marine bryozoan, has been shown in tissue culture to activate protein kinase C. This agent has recently undergone Phase I testing in humans given either as a bolus i.v. injection or a continuous infusion. To understand how bryostatin 1 might be used best as an anticancer agent, a study of the pharmacokinetics, tissue distribution, metabolism, and elimination of bryostatin 1 in mice was undertaken, using [C26-3H]-labeled bryostatin 1. Following i.v. administration, the plasma disappearance curve for bryostatin 1 could be described by a two-compartment model, with half-lives of 1.05 and 22.97 h, respectively. In contrast, the plasma disappearance curve for bryostatin 1 administered i.p. was better described by a first order absorption one-compartment model, with an absorption half-life of 0.81 h and an elimination half-life of 28.76 h, respectively. The majority of radioactivity in plasma was associated with the intact drug for up to 24 h after dosing. In the first 12 h after i.v administration, urinary excretion represented the major pathway of elimination, with 23.0 +/- 1.9% (mean +/- SD) of the administered dose excreted. Within 72 h after i.v. administration, approximately equal amounts of radioactivity (40%) were excreted in feces compared to urine. Bryostatin 1 was widely distributed in many organs but concentrated in the lung, liver, gastrointestinal tract, and fatty tissue. The concentration in the gastrointestinal tract, along with the fecal excretion, suggests the possibility of enterohepatic circulation of this drug. In summary, this study demonstrates that bryostatin 1 is relatively stable in vivo, widely distributed but concentrated in some major tissues, and rapidly excreted first through urine and at later times through the feces. The data from this animal study should be useful in the design of future human trials with this anticancer drug.

Three distinct neuronal phenotypes exist in embryonic rat hippocampal neurons cultured in basic fibroblast growth factor

The possibility that neurons cultured in basic fibroblast growth factor (bFGF) are heterogeneous raises concerns about their subsequent use in gene transfection and transplantation studies. We have examined the fate of embryonic hippocampal neurons in bFGF culture, and now conclude that these cells are not only heterogeneous, but possess neurons of various stages of development. Morphological and immunocytochemical analysis reveal three distinct developmental classes of neurons are present in extended bFGF culture. This tripartite classification is supported by electrophysiological analysis, which reveals that upon depolarization, neurons with precursor and juvenile neuron morphologies are unable to fire action potentials. The third class of neurons, which resemble age-matched polarized neurons in standard serum culture, fired multiple action potentials indicative of a mature phenotype. These data show neurons at multiple developmental stages co-exist in bFGF culture, and provide an experimental basis for their classification.

Effects of continuous passive motion and immobilization on synovitis and cartilage degradation in antigen induced arthritis

OBJECTIVE

To determine the effects of continuous passive motion (CPM) and immobilization on synovitis and cartilage degradation in an experimental model of chronic inflammatory, antigen-induced arthritis.

METHODS

After bilateral arthritis induction of knee joints in 22 NZW rabbits, one knee was immobilized with a flexion splint while the opposite knee received CPM.

RESULTS

After 2 weeks (n = 10), the CPM treated knees had significantly greater joint swelling, synovial effusion, and histologic synovitis scores compared to its opposite immobilized knees. However, the total cartilage degradation score showed no statistically significant difference between the two treatments. When the treatments were discontinued after 2 weeks and animals were allowed intermittent active motion of both knees in cages for 4 weeks (n = 12), no statistically significant difference in joint swelling, synovial effusion, and histologic synovitis score was observed between the 2 treatments. The articular cartilage degradation, however, was significantly greater in the immobilized knees compared to its opposite CPM treated knees. Five of 12 immobilized knees had articular surface erosion compared to none in the CPM treated knees. Loss of cellularity was also significantly greater in the immobilized knees.

CONCLUSION

Although CPM produced greater synovitis at 2 weeks, articular cartilage was better preserved in the knees treated with CPM than immobilization at 6 weeks.

Long-term bFGF neuronal culture: reintroduction into serum medium yields neurons and non-neuronal cells with neuronal characteristics

The potential use of bFGF immortalized cells as hosts for delivering foreign genes into nervous tissue led us to examine the effect of maintaining, E-18 hippocampal neurons for extended periods in bFGF culture prior to transfer into a standard, serum-containing, medium. We found: (1) many, if not most, precursors seen in bFGF, mature into glia and not into primary neurons after medium exchange; (2) the electrophysiology of the neurons which do mature after medium transfer and replating, is similar to that of neurons in standard cultures; (3) extended culture in bFGF prior to cell harvesting and replating into standard medium generates neurons from the precursors that possess proper neuronal polarization, morphology, and electrophysiology; and (4) extended bFGF also induces the expression, on transfer into standard medium, of an additional cell type with a distinct non-neuronal morphology that stains with the neuronal marker MAP-2. These results illustrate the need for additional characterization of long-term growth factor effects on maintained progenitor cells prior to their use in gene therapy and transplantation.

In vivo and in vitro biosynthesis of saponins in sea cucumbers

The triterpene precursor of saponins in sea cucumbers has been identified as parkeol [lanost-9(11)-en-3 beta-ol] [1]. Dissection of the sea cucumbers Holothuria floridea and Actinopyga agassize after incubations with radiolabeled parkeol demonstrated that saponin biosynthesis occurs exclusively in the Cuvier gland. This result was corroborated by incubating a cell-free extract of the Cuvier gland with labeled parkeol and observing transformation of the precursor to saponins.