Prenatal Zika virus infection has sex-specific effects on infant physical development and mother-infant social interactions

There is enormous variation in the extent to which fetal Zika virus (fZIKV) infection affects the developing brain. Despite the neural consequences of fZIKV infection observed in people and animal models, many open questions about the relationship between infection dynamics and fetal and infant development remain. To further understand how ZIKV affects the developing nervous system and the behavioral consequences of prenatal infection, we adopted a nonhuman primate model of fZIKV infection in which we inoculated pregnant rhesus macaques and their fetuses with ZIKV in the early second trimester of fetal development. We then tracked their health across gestation and characterized infant development across the first month of life. ZIKV-infected pregnant mothers had long periods of viremia and mild changes to their hematological profiles. ZIKV RNA concentrations, an indicator of infection magnitude, were higher in mothers whose fetuses were male, and the magnitude of ZIKV RNA in the mothers' plasma or amniotic fluid predicted infant outcomes. The magnitude of ZIKV RNA was negatively associated with infant growth across the first month of life, affecting males' growth more than females' growth, although for most metrics, both males and females evidenced slower growth rates as compared with control animals whose mothers were not ZIKV inoculated. Compared with control infants, fZIKV infants also spent more time with their mothers during the first month of life, a social behavior difference that may have long-lasting consequences on psychosocial development during childhood.

Dural venous sinus stenting technique for idiopathic intracranial hypertension in patients with tortuous venous anatomy

Venous sinus stenting (VSS) for medically refractory idiopathic intracranial hypertension (IIH) is emerging as a safe and effective alternative to shunting. However, stent navigation past the jugular bulb with commonly used carotid stenting systems via femoral access in cases with tortuous venous anatomy can present a challenge, leading to procedural failure. We present a technical refinement using a cervical access and peripheral vascular stent with a more stable 0.035-in. delivery platform as an alternative to the traditional approach to simplify the procedure and overcome the technical difficulties in cases with tortuous venous anatomy. Our institutional database for patients who had IIH and undergone VSS using the peripheral vascular stent between 2013 and 2023 was retrospectively reviewed. Data on 36 patients (33 women, 3 men, mean age 32 years) was collected. VSS was technically successful in all patients (100%) without major complications or thrombosis. There was one case of minor neck cellulitis treated with oral antibiotics. Three patients underwent repeat stenting, and 2 patients had ventriculoperitoneal shunt placement after stenting due to persistent or recurrent symptoms. All patients (100%) had improvement or resolution of papilledema; however, six patients had evidence of optic atrophy and persistent vision loss. Headache was resolved or improved in 91% of patients. In the presence of tortuous venous anatomy, VSS using cervical access and a peripheral vascular stent with a more stable 0.035-in. delivery platform can be considered as a safe and effective alternative approach with shorter procedure time. This approach is particularly advantageous in situations where the procedure is prolonged or high dose of contrast has been administered due to the technical challenges associated with the traditional use of carotid systems via femoral access for stent delivery.

System-wide integration of patient reported outcome measure collection through an electronic medical record system: A state-wide retrospective study

BACKGROUND AND PURPOSE

In spine neurosurgery practice, patient-reported outcome measures (PROMs) are tools used to convey information about a patient's health experience and are an integral component of a clinician's decision-making process as they help guide treatment strategies to improve outcomes and minimize pain. Currently, there is limited research showing effective integration strategies of PROMs into electronic medical records. This study aims to provide a framework for other healthcare systems by outlining the process from start to finish in seven Hartford Healthcare Neurosurgery outpatient spine clinics throughout the state of Connecticut.

METHODS

On March 1, 2021, a pilot implementation program began in one clinic and on July 1, 2021, all outpatient clinics were implementing the revised clinical workflow that included the electronic collection of PROMs within the electronic health record (EHR). A retrospective chart analysis studied all adult (18+) new patient visits in seven outpatient clinics by comparing the rates of PROMs collection in Half 1 (March 1, 2021-August 31, 2022) and in Half 2 (September 1, 2022-February 28, 2022) across all sites. Additionally, patient characteristics were studied to identify any variables that may lead to higher rates of collection.

RESULTS

During the study period, 3528 new patient visits were analyzed. There was a significant change in rates of PROMs collection across all departments between H1 and H2 (p < 0.05). Additional significant predictors for PROMs collection were the sex and ethnicity of the patient as well as the provider type for the visit (p < 0.05).

CONCLUSIONS

This study proved that implementing the electronic collection of PROMs into an already existing clinical workflow reduces previously identified collection barriers and enables PROMs collection rates that meet or exceed current benchmarks. Our results provide a successful step-by-step framework for other spine neurosurgery clinics to implement a similar approach.

Standard of Care During a Crisis: What Should a Surgeon Know (and Do)?

Numerous catastrophic events in the 21st century have motivated renewed discussion regarding whether the traditional definition of standard of care appropriately applies to clinical decision-making in crisis scenarios. Some authorities have proposed the adoption of a crisis standard of care, which refines physician responsibilities during a crisis event in accordance with population health principles. However, this proposal is fraught with controversy, and current medical and legal scholarship on this topic remains complex and conflicted. To clarify these points and provide practicing neurosurgeons with guidance, we provide a review of current literature on the evolving definitions of crisis standard of care. Additionally, we provide an assessment of the implications of a crisis standard of care, as it relates to legal liability, clinical ethics, and neurosurgical practice.

Neurosurgery at UT Southwestern Medical Center: 1956-2020

The history of neurosurgery at UT Southwestern Medical Center in Dallas, Texas, is reviewed. Kemp Clark, MD, started the academic neurosurgical practice at Parkland Hospital in 1956. Clark developed a robust training program that required the resident to operate early. In 1972, the Dallas Veterans Affairs Hospital was added to the training program. Duke Samson, MD, became chair in 1988. He emphasized technical excellence and honest reporting of surgical outcomes. In 1989, Zale Lipshy University Hospital opened and became a center for neurosurgical care, and Hunt Batjer, MD, became chair in 2012. The program expanded significantly. Along with principles established by his predecessors, Batjer emphasized the need for all neurosurgeons to engage the community and to be active in policy leadership through local and national organizations. During his tenure, the pediatric neurosurgery group at Children's Medical Center Dallas was integrated with the department, and a multidisciplinary spine service was developed. In 2014, the Peter O'Donnell Jr. Brain Institute was established, and the William P. Clements Jr. University Hospital opened. For 64 years, UT Southwestern Medical Center has been fertile ground for academic neurosurgery, with a strong emphasis on excellence in patient care.

Fluoroscopic Cranial Radiation Exposure in Spine Surgery: A Prospective Single-Center Evaluation in Operating Room Personnel

Background

Cranial radiation exposure during instrumented spine surgery is not well documented. We set out to measure this risk to the patient, surgeon, surgical resident, and scrub technician during these procedures.

Methods

Forty-seven individuals were enrolled during a 1.5-year period between October 2014 and March 2016 at the University of New Mexico Department of Neurosurgery. Radiation doses were obtained through electronic dosimeters placed on the surgical cap over the temporal scalp (bilaterally on surgeon and resident assist, unilaterally on surgical scrub on the side facing radiation source) and on the midline of the patient's exposed cranium.

Results

Of the 47 procedures, 39 (83%) were open and 8 (17%) were minimally invasive or percutaneous instrumented procedures. A total of 91 motion segments were treated, with a mean of 1.9 levels per case (57% lumbosacral, 34% cervical, and 2.1% thoracic). Total fluoroscopic time was 12.9 minutes. Mean dose per case (mrem/case) was calculated for the spine surgeon (1.4), resident assist (1.4), surgical scrub (1.2), and the patient (3.6). All doses were within federal safety guidelines. A spine surgeon would need to perform more than 1400 cases per year to reach the current federal maximum permissible dose for head exposure.

Conclusions

There was no difference in cranial radiation exposure between operating room staff during spine surgeries. Moreover, the doses measured at the cranium were within national safety limits. Current protective technologies have significantly reduced the amount of ionizing radiation exposure during routine spine procedures; however, changes in behavior or equipment may further reduce radiation exposure to health care workers.

Clinical Relevance

Radiation exposure to patients and hospital staff remains a major concern in the practice of modern spine surgery. Cranial exposure remains the only established environmental risk factor for brain tumors, such as gliomas and meningiomas. Our study shows that all those exposed to radiation during spine surgery had cranial doses well within the national safety limits.

Middle Cerebral Artery Aneurysm "Neck Overhang": Decreased Postclipping Residual Using the Intersecting Clipping Technique

BACKGROUND

Middle cerebral artery (MCA) aneurysms continue to be viewed by many as primarily surgical entities.

OBJECTIVE

To introduce a new, easily measurable dimension termed "neck overhang," defined as the amount of the aneurysm that extends proximal to the 2 dimensionally defined "neck" and to evaluate the utility of the intersecting clipping technique (use of straight clip and intersecting fenestrated clip) to adapt to this overhanging segment's specific dimensions and achieve better obliteration of the MCA aneurysms.

METHODS

We reviewed retrospectively 100 MCA aneurysms treated surgically over the last 10 yr at our institution. We identified the clipping technique that was performed (intersecting vs "standard" technique) and we evaluated the presence of a postoperative remnant. We then correlated these with the aneurysm's overhanging neck length.

RESULTS

Forty-three aneurysms were treated with the intersecting clipping technique. The overall rate of remnant was 16%. In the standard group, the rate of remnant was 23%, whereas with intersecting clipping that was 7% (P = .029). Within the standard clipping group, we found that the optimum threshold for length of the neck overhang was ≥1.9 mm in order to predict the occurrence of residual. Applying this threshold to the intersecting clipping technique group resulted in a reduction in remnant from 35% in the standard group to 9%.

CONCLUSION

Neck overhang >1.9 mm is associated with a higher chance of postclipping residual aneurysm in MCA aneurysms. The intersecting clipping technique is a versatile technique that can conform to various aneurysms' geometry and can reduce the rate of post clipping residual for aneurysms with high neck overhang.

Multimodal analgesia using intrathecal diamorphine, and paravertebral and rectus sheath catheters are as effective as thoracic epidural for analgesia post-open two-phase esophagectomy within an enhanced recovery program

Thoracic epidural (TE) analgesia has been the standard of care for transthoracic esophagectomy patients since the 1990s. Multimodal anesthesia using intrathecal diamorphine, local anesthetic infusion catheters (LAC) into the paravertebral space and rectus sheaths and intravenous opioid postoperatively represent an alternative option for postoperative analgesia. While TE can provide excellent pain control, it may inhibit early postoperative recovery by causing hypotension and reducing mobilization. The aim of this study is to determine whether multimodal analgesia with LAC was effective with respect to adequate pain management, and compare its impact on hypotension and mobility. Patients receiving multimodal LAC analgesia were matched using propensity score matching to patients undergoing two-phase trans-thoracic esophagectomy with a TE over a two-year period (from January 2015 to December 2016). Postoperative endpoints that had been evaluated prospectively, including pain scores on movement and at rest, inotrope or vasoconstrictor requirements, and hypotension (systolic BP < 90 mmHg), were compared between cohorts. Out of 14 patients (13 male) that received LAC were matched to a cohort of 14 patients on age, sex, and comorbidity. Mean and maximum pain scores at rest and movement on postoperative days 0 to 3 were equivalent between the groups. In both cohorts, 50% of patients had a pain score of more than 7 on at least one occasion. Fewer patients in the LAC group required vasoconstrictor infusion (LAC: 36% vs. TE: 57%, P = 0.256) to maintain blood pressure or had episodes of hypotension (LAC: 43% vs. TE: 79%, P = 0.05). The LAC group was more able to ambulate on the first postoperative day (LAC: 64% vs. TE: 43%, P = 0.14) but these differences were not statistically significant. Within the epidural cohort, three patients had interruption of epidural due to dislodgement or failure of block compared to no disruption in the multimodal local anesthesia catheters group (P = 0.05). Therefore, multimodal anesthesia using spinal diamorphine with combined paravertebral and rectus sheath local anesthetic catheters appears to provide comparable pain relief post two-phase esophagectomy and may provide more reliable and safe analgesia than the current standard of care.

Professional behaviours demonstrated by undergraduate dental students using an incident reporting system

Critical incident reporting is widely used across healthcare and other sectors for reporting adverse events or behaviours. More recently it has been used in medical education as a means of assessing student professionalism. The aims of this study were to determine the usage of critical incident forms when reporting behaviours related to professionalism demonstrated by undergraduate dental students, and the types of behaviours exhibited. Three types of form could be awarded for highly professional (green), minor unprofessional (yellow) and serious unprofessional (red) behaviours. All forms completed over a two-year period were analysed recording the year of student, type of card and demographic of the member of staff reporting the incident. All text relating to the nature of the incident was entered into a qualitative data analysis software package and analysed thematically. In total, 583 cards were awarded, 55% green, 34% yellow and 11% red. Seventy-four percent of cards were awarded in a clinical environment, with administrative staff using them the most (29%). The overwhelming professional behaviours demonstrated related to altruism. The most common unprofessional behaviours related to a lack of conscientiousness, although a greater range of common unprofessional behaviours were reported. In conclusion, critical incidents forms were widely used for reporting both professional and unprofessional behaviours particularly in clinical environments by a range of staff. Such forms may be a valuable addition to the professionalism assessment portfolio, capturing behaviours not previously reported using traditional methods.

A novel single twist-drill access device for multimodal intracranial monitoring: a 5-year single-institution experience

BACKGROUND

Multimodal intracranial monitoring in the neurosurgical patient requires insertion of probes through multiple craniostomies.

OBJECTIVE

To report our 5-year experience with a novel device allowing multimodal monitoring though a single twist-drill hole.

METHODS

All devices (Hummingbird Synergy, Innerspace) were placed at the Kocher point between 2008 and 2013 at our institution. An independent clinical research nurse prospectively collected data on all bedside placements. Placement accuracy was graded on computed tomography scan as grade 1 (ipsilateral frontal horn or third ventricle), grade 2 (contralateral lateral ventricle), and grade 3 (anywhere else). Infection was monitored with serial cerebrospinal fluid samples.

RESULTS

Two hundred seventy-five devices (198 at bedside, 77 in operating room) were placed in patients with spontaneous subarachnoid hemorrhage (49%), traumatic brain injury (47%), and others (4%) for a median duration of 6 days. A junior (postgraduate year 1-2), midlevel (postgraduate year 3-4), or senior resident (postgraduate year 5-6) placed 39%, 32%, and 29% of the devices, respectively. Ninety-two percent of all devices placed were draining cerebrospinal fluid, ie, were grade 1 (75%) or 2 (17%). Placement accuracy did not vary with level of training. Complications included hemorrhage (10%) and infection (4%), with 1 patient requiring intraparenchymal hematoma evacuation and a second requiring abscess drainage. These rates were lower than reported in the literature for standard external ventricular drains.

CONCLUSION

Hummingbird Synergy is a novel single-port access device for multimodal intracranial monitoring that can be placed safely at the bedside or in the operating room with placement accuracy and has a complication profile similar to or better than that for standard external ventricular drains.

Delayed rebleeding of a spontaneously thrombosed aneurysm after subarachnoid hemorrhage

Background:

This report provides a rare documentation of spontaneous thrombosis of a ruptured aneurysm followed by delayed recanalization and subsequent rerupture.

Case Description:

A 47-year-old female presented with spontaneous subarachnoid hemorrhage (SAH). Four aneurysms were identified on CT angiogram including a basilar apex aneurysm, considered source of bleeding. Cerebral angiogram on postbleed day (PBD) #1 showed spontaneous thrombosis of basilar apex aneurysm. The patient was discharged to a nursing home on PBD #18 after two subsequent studies showed no recanalization of the basilar aneurysm. The patient returned on PBD #26 with a second episode of spontaneous SAH. The previously thrombosed basilar aneurysm had recanalized and reruptured, which was now treated with coil embolization.

Conclusion:

We are not aware of a previous report of saccular cerebral aneurysm documenting spontaneous thrombosis after SAH and recanalization with second hemorrhage. This occurrence presents a dilemma regarding the timing and frequency of subsequent cerebrovascular imaging and treatment.

A comparison of grades awarded by peer assessment, faculty and a digital scanning device in a pre-clinical operative skills course

OBJECTIVE

The aim of this study was to compare the grades awarded by two experienced assessors with peer-assessment marks and measurements from a digital scanning device (Prepassistant; KaVo, Biberach, Germany), for full gold crown preparations completed in a pre-clinical operative skills course on typodont teeth.

METHODS

Seventy-eight preparations on typodont teeth were randomised and assessed by all three methods. Agreement was measured using weighted kappa statistics, and mean rank scores given by the Friedman test.

RESULTS

The highest agreement was seen between the experienced assessors (0.38), closely followed by peer assessment and experienced assessor agreement (0.36, 0.29). Despite this, the results indicate poor levels of agreement. No agreement was seen between any of the assessment methods when compared to the digital scanning device.

CONCLUSIONS

The findings of this study could be related to the difficulty of calculating a single grade from the output of the device, in addition to the inability of the machine to assess all the factors necessary for an acceptable preparation. From this study, it can be concluded that this device is not suitable for calculating grades when used in isolation. Further research could explore the role of the Prepassistant in providing student feedback, its potential to enhance the learning experience and the subsequent effect on performance.

Early mental health morbidity and later smoking at age 17 years

BACKGROUND

We examined the relationship between the onset and pattern of childhood mental health disorders and subsequent current smoking status at age 17 years.

METHOD

Data were from a prospective cohort study of 2868 births of which 1064 supplied information about their current smoking at 17 years of age. The association between the onset and pattern of clinically significant mental health disorders in the child and subsequent smoking at age 17 years was estimated via multivariable logistic regression.

RESULTS

Relative to 17 year olds who never had an externalizing disorder, 17-year-olds who had an externalizing disorder at age 5, 8 or 14 years were, respectively, 2.0 times [95% confidence interval (CI) 1.24-3.25], 1.9 (95% CI 1.00-3.65) or 3.9 times (95% CI 1.73-8.72) more likely to be a current smoker. Children with an ongoing pattern of externalizing disorder were 3.0 times (95% CI 1.89-4.84) more likely to be smokers at the age of 17 years and those whose mothers reported daily consumption of 6-10 cigarettes at 18 weeks' gestation were 2.5 times (OR 2.46, 95% CI 1.26-4.83) more likely to report smoking at 17 years of age. Associations with early anxiety and depression in the child were not found.

CONCLUSIONS

Current smoking in 17-year-olds may be underpinned by early emergent, and then, ongoing, externalizing disorder that commenced as young as age 5 years as well as exposure to early prenatal maternal smoking. The associations documented in adults and adolescents that link tobacco smoking and mental health are likely to be in play at these early points in development.

Successful reversal of threatening carotid artery occlusion in HIV-associated non-aneurysmal vasculitis

We report a case of HIV-associated carotid vasculitis, causing cerebral infarction. Immediate corticosteroid treatment was followed by improvement, with radiological documentation of reversal of the vasculitic changes, preventing arterial occlusion. Vasculitis should be considered as a diagnosis in stroke in HIV and steroid treatment considered as a potentially life-saving intervention.

Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (onyx) arterial embolization as the primary modality: short-term results

OBJECT

A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials.

METHODS

The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques.

RESULTS

Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment.

CONCLUSIONS

Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.

A case of severe eczema following use of imiquimod 5% cream

Imiquimod 5% cream, an immune response modifier licensed for treatment of external ano-genital warts and superficial basal cell carcinomata, is known to cause local erythema, oedema and, rarely, exacerbation of psoriasis. We describe a case of exacerbation of eczema following application of this cream in a man with penile warts.

Complications of preoperative embolization of cerebral arteriovenous malformations

Object. Preoperative embolization is viewed by the authors as a useful adjunct in the surgical management of cerebral arteriovenous malformations (AVMs). This study was performed to determine the rate of significant complication in patients undergoing this procedure.

Methods. Demographic, anatomical, and procedure data were collected prospectively. The treating physician reported complications. In addition, a review of medical records including procedure reports, operative reports, and discharge summaries was performed. Univariate statistical analysis was performed to determine if any of the variables was predictive of a poor outcome of embolization (death or permanent neurological deficit).

Endovascular procedures for embolization were performed 339 times in 201 patients during an 11-year period. Female patients comprised 53.7% of the study group and 85.6% of the AVMs were supratentorial. Embolization was performed using polyvinyl alcohol particles, N-butyl cyanoacrylate, detachable coils, and/or the liquid polymer Onyx. Analyzed by procedure, a poor result of embolization occurred in 7.7%. Analyzed by patient, 11% died or had a permanent neurological deficit as a result of the embolization. None of the demographic, anatomical, or procedure variables identified were predictive of a poor outcome.

Conclusions. Preoperative embolization may gradually reduce flow to an AVM, reduce intraoperative blood loss, and reduce operative time. The risks of this procedure, however, are not insignificant and must be considered in planning treatment for patients with AVMs.

Outcome after subarachnoid hemorrhage from a very small aneurysm: a case-control series

Object. A case-control analysis of patients with SAH was performed to compare risk factors and outcomes at 6 months posthemorrhage in patients with a very small aneurysm compared with those with a larger aneurysm.

Methods. All patients with SAH who were treated between January 1998 and December 1999 were studied. A very small aneurysm was defined as “equal to or less than 5 mm in diameter.” Clinical data and treatment summaries were maintained in an electronic database. The Glasgow Outcome Scale (GOS) score was determined by an independent registrar.

One hundred twenty-seven patients were treated. A very small aneurysm was the cause of SAH in 42 patients (33%), whereas 85 (67%) had aneurysms larger than 5 mm (mean diameter 11 mm). There were no differences in demographic variables or medical comorbidities between the two groups. Thick SAH (Fisher Grade 3 or 4) was more common in patients with a very small aneurysm than in those with a larger aneurysm (p = 0.028). One hundred eight patients underwent microsurgery (85%), 15 underwent coil embolization (12%), and four (3%) required both procedures. Vasospasm occurred in nine patients (21%) with very small aneurysms compared with 14 (16%) with larger aneurysms (p = 0.62). Shunt-dependent hydrocephalus occurred in nine patients (21%) with very small aneurysms and in 19 (22%) with larger aneurysms (p = 1). The mean GOS score for both groups was 4 (moderately disabled) at 6 months.

Conclusions. Small aneurysms produce thick SAH more often than larger aneurysms. There is no difference in outcome after SAH between patients with a very small aneurysm and those with a larger aneurysm.

Treatment and outcome in 30 patients with posterior cerebral artery aneurysms

OBJECT

The records of 30 patients with posterior cerebral artery (PCA) aneurysms treated during a 12-year period were reviewed to determine outcome and the risk of visual field deficit associated with PCA sacrifice.

METHODS

Clinical data and treatment summaries for all patients were maintained in an electronic database. The Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) scores were determined by an independent registrar. Visual field changes were determined by review of medical records. Twenty-eight patients were treated with open surgery, one of them after an attempt at detachable coil embolization failed. Two patients underwent successful endovascular PCA sacrifice. The mean GOS and mRS scores in 18 patients with unruptured aneurysms were 4 and 2, respectively, at discharge. Subarachnoid hemorrhage (SAH) from other aneurysms and neurological deficits caused by the PCA lesion or underlying disease contributed to poor outcomes in this group. The mean GOS and mRS scores in 12 patients with ruptured aneurysms were 4 and 4, respectively, at discharge. One patient died of severe vasospasm. Neurological deficits secondary to SAH and, in one patient, treatment of a concomitant arteriovenous malformation contributed to poor outcomes in the patients with ruptured aneurysms. Seven patients with normal visual function preoperatively underwent PCA occlusion. One patient (14%) developed a new visual field deficit.

CONCLUSIONS

Optimal treatment of PCA aneurysms is performed via one of several surgical approaches or by endovascular therapy. The approach is determined, in part, by the anatomical location and size of the aneurysm and the presence of underlying disease and neurological deficits.

cDNA cloning of the polymeric immunoglobulin receptor of the marsupial Macropus eugenii (tammar wallaby)

cDNA encoding a marsupial polymeric immunoglobulin receptor (pIgR) was isolated from Macropus eugenii (tammar wallaby) mammary lymph node primarily by reverse transcriptase coupled polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) PCR. This resulted in a 5' truncated clone and, in order to obtain the full-length sequence, genomic walking PCR was utilized. The complete sequence consists of 2696 bp of cDNA and encodes a predicted polypeptide of 732 amino acids. The wallaby sequence is highly conserved in relation to the only other reported marsupial pIgR sequence, that of Trichosurus vulpecula (brushtail possum), having a nucleotide identity of 86.7% and a deduced amino acid identity of 79.9%. The wallaby nucleotide sequence also has a moderate degree of similarity with the pIgR sequences of eutherian mammals, being most similar to that of the rat, with an identity of 63.1%. At the amino acid level, in comparison to eutherian sequences, the wallaby pIgR is most similar to that of humans with an identity of 52.6%. pIgR phylogenetic trees were constructed for tammar wallaby, brushtail possum and several eutherian mammal cDNA and deduced amino acid sequences. In both DNA and protein analyses, the eutherian sequences formed a sister clade to the exclusion of the marsupial sequences, in agreement with the current view of mammalian evolution.

Exhaled nitric oxide concentrations: online versus offline values in healthy children

Exhaled nitric oxide (FE(NO)) is a noninvasive and practical method to assess airway inflammation. We conducted this investigation to determine the most appropriate flow rate to measure FE(NO) and to obtain reference values for FE(NO) in children. FE(NO) was measured in 112 healthy 6-18 year olds (60 males) at 4 expiratory flow rates (46, 31, 23, and 15 mL/sec) using a chemiluminescent nitric oxide analyzer. Offline and online analyses were done to determine FE(NO) intraclass correlation coefficients, the relationship between FE(NO) and expiratory flow rates, and the effects of age and gender on these measurements. The major findings were: 1) intraclass correlation coefficients for FE(NO) and flow rates ranged from 0.92-0.99 for offline values, and 0.99 for all online values; 2) variation at an expiratory flow rate of 46 mL/sec (SD, 9.39) was considerably less than at other flows, especially at 15 mL/sec (SD, 26.55); 3) FE(NO) increased as flow rates decreased for both offline and online values; 4) there were no significant differences and good agreement between offline bag and online FE(NO) values at 31 and 46 mL/sec expiratory flows; and 5) using multiple regression, significant predictors of FE(NO) were flow, body surface area, age, and FEF(25-75). We have provided FE(NO) values in healthy children and propose that the ideal expiratory flow rate for FE(NO) measurements in children using the single breath technique is between 30-50 mL/sec.

Steal affecting the central nervous system

Steal is a pathophysiological process in which increased blood flow through a low-resistance vascular bed is sufficient to divert flow away from a region of the central nervous system. Three disease states in which steal may cause neurological deficits due to central nervous system ischemia are reviewed. Subclavian steal occurs when stenosis of the subclavian artery proximal to the vertebral origin causes retrograde flow in the left vertebral artery. Patients with anatomic subclavian steal usually do not develop neurological symptoms but may rarely present with posterior circulation ischemia. Arteriovenous malformations alter cerebral blood flow patterns and regional perfusion pressure. It has been hypothesized that cerebral arteriovenous malformations may cause neurological deficits due to steal and that these deficits may be cured with arteriovenous malformation treatment. Intra-arterial pressure measurements and transcranial velocity studies show regional hemodynamic alterations. However, these changes have not been correlated with presenting symptoms. Evidence from single-photon emission computed tomography does suggest a relationship between regional hypoperfusion and neurological deficits. Coarctation of the aorta may divert flow from the spinal cord circulation through intercostal arteries distal to the stenosis. This is a possible but unproven mechanism of myelopathology. Steal syndromes may be amenable to treatment by open surgical or endovascular approaches. Experimental studies of the pathophysiology of steal are strengthened by precise definitions of the measured parameters and innovative applications of technology.

c-Myc initiates illegitimate replication of the ribonucleotide reductase R2 gene

The mechanisms through which the oncoprotein c-Myc initiates locus-specific gene amplification are not understood. When analysing the initiation mechanism of c-Myc-dependent amplification of the mouse ribonucleotide reductase R2 (R2) gene, we observe c-Myc-dependent initiation of illegitimate DNA replication of the R2 gene. We demonstrate multiple simultaneous c-Myc-induced R2 replication forks, whereas R2 normally replicates with a single fork. In contrast, cyclin C replicates with only a single replication fork irrespective of c-Myc deregulation. In addition to de novo replication forks, c-Myc also initiates bi-allelic replication of R2, abrogating its normal mono-allelic replication pattern. Moreover, several chromosomal regions also display c-Myc-induced illegitimate replication profiles. Thus, c-Myc can act as an illegitimate replication-licensing factor that promotes de novo replication initiation and illegitimate replication timing that adversely impacts upon genomic stability.

Nonoxynol-9 causes rapid exfoliation of sheets of rectal epithelium

Nonoxynol-9 (N-9) containing spermicides and other N-9 containing products are commonly used as lubricants during rectal intercourse. We have previously demonstrated that rectal application of N-9 products in mice can cause exfoliation of epithelial cells, increasing the probability of infection by HSV-2. To determine if N-9-containing products would have a similar effect on the rectal epithelium in humans, the application of K-Y Plus and ForPlay, both over-the-counter (OTC) N-9 products, were compared to the application of two formulations, carrageenan and methyl cellulose, that do not contain N-9. The effects of each formulation were evaluated in 4 human participants. Light and electron microscope examination of rectal lavage specimens collected 15 min post application of N-9 products revealed the presence of sheets of epithelium. Each sheet contained hundreds of epithelial cells that included columnar and goblet cells, varieties of cells typical of rectal epithelial morphology. Sheets of epithelium were not observed in rectal lavage specimens collected 8 to 12 hr post N-9 product use or in either of the timed lavages involving non-N-9 containing formulations. In addition, no sheets of epithelial cells were observed in the baseline lavage specimens. We conclude that the rectal use of N-9-containing products causes a rapid exfoliation of extensive areas of the rectal epithelium. Exfoliation of the epithelium is no longer observed at 8 hr. It is reasonable to assume that the loss of the protective epithelium would render a person more at risk for infection by HIV and other sexually transmitted pathogens. We, therefore, caution against the use of N-9-containing products during rectal intercourse.

FE(NO): relationship to exhalation rates and online versus bag collection in healthy adolescents

Measurement of exhaled nitric oxide (FE(NO)) is a noninvasive and practical method for assessing airway inflammation. We conducted this investigation to determine the most appropriate flow rate for FE(NO) measurement and to obtain normal values for FE(NO). We determined which expiratory flow was easy to sustain, generated reproducible values, and provided good correlation between offline and online measurements. Thirty-two healthy subjects (15- 18 yr old) underwent spirometry and FE(NO) measurements, using a chemiluminescent NO analyzer at expiratory flow rates of 46, 31, 23, 15, 10, 7, 5, and 4 ml/s. The major findings were as follows: (1) FE(NO) increased as flow rates decreased, with strong correlation between FE(NO) values and flow rates at the four highest flows (0. 85- 0.93, p < 0.001); (2) there were no significant differences and good agreement between offline bag and online FE(NO) values for the four highest flows (p < 0.09-0.83); (3) online FE(NO) values increased with age 15-17 yr at all flow rates, but decreased at age 18 yr; and (4) using multiple regression, significant predictors of FE(NO) were flow, body surface area, age, and FEF(25-75). On the basis of these results, we provide FE(NO) values for healthy adolescents and propose that the ideal flow rate for children is between 30 and 50 ml/s.

Screening for hearing loss and middle-ear disorders in children using TEOAEs

The purpose of this research was to obtain the sensitivity and specificity of transient evoked otoacoustic emission (TEOAE) screening procedures compared with conventional audiometric pure-tone screening and tympanometry. Pass/refer values were obtained from a group of 297 ears of 152 preschool and school-aged children, 3 to 8 years of age. The sensitivity and specificity of the TEOAE screenings compared with the pure-tone screenings were 81% and 95%, respectively. The sensitivity and specificity of TEOAE screenings compared with tympanometric screenings were 60% and 91%, respectively.

Emergency management of ischemic stroke

The accurate diagnosis of acute ischemic stroke is possible using clinical skills and diagnostic tools that are familiar to all neurosurgeons. Avoidance of immediate complications relies on the fundamentals of critical care. Effective treatment for ischemic stroke is available in the form of intravenous thrombolysis, but many stroke patients are denied this therapy because of the narrow window of opportunity for safe administration. Intra-arterial delivery may extend this benefit to a greater number of patients and may eventually prove more effective than intravenous treatment. Surgical treatment in a small number of ischemic stroke patients can be lifesaving and may afford reasonable functional recovery. This article discusses typical clinical presentations and differential diagnosis, diagnostic imaging for ischemic stroke, and possible treatments.

Impairment of cingulothalamic learning-related neuronal coding in rabbits exposed to cocaine in utero: general and sex-specific effects

Neuronal activity was recorded in the cingulate cortex and the limbic thalamus in Dutch-belted rabbits (Oryctolagus cuniculus) exposed to cocaine (8 mg/kg/day i.v.) or saline in utero during acquisition and reversal learning of a discriminative avoidance response. Anterior cingulate cortical excitatory training-induced activity (TIA) was attenuated in cocaine-exposed female rabbits during acquisition and reversal learning, but only during reversal learning in male rabbits. Posterior cingulate cortical excitatory TIA was lessened in cocaine-exposed rabbits during acquisition, whereas discrimination between the positive and negative cues was enhanced. Neuronal firing was attenuated in the anterior ventral thalamus in cocaine-exposed rabbits during acquisition and reversal learning. Behavioral learning was normal in cocaine-exposed rabbits. Other data suggest that rabbits exposed to cocaine in utero exhibit a learning deficit when trained with nonsalient cues.

Rebound intracranial hypertension in dogs after resuscitation with hypertonic solutions from hemorrhagic shock accompanied by an intracranial mass lesion

We compared intracranial pressure (ICP) and cerebral blood flow (CBF) in dogs after inflating a subdural intracranial balloon to increase ICP to 20 mm Hg, inducing hemorrhagic shock (mean arterial pressure [MAP] of 55 mm Hg), and infusing a single bolus of fluid consisting of either 54 mL/kg of 0.8% saline (SAL), 6 mL/kg of 7.2% hypertonic saline (HS), 20% hydroxyethyl starch (HES) in 0.8% SAL, or a combination fluid (HS/HES) containing 20% HES in 7.2% saline. Twenty-six dogs were ventilated with 0.5% halothane in N2O and O2 (60:40 ratio). As ICP was maintained at 20 mm Hg, rapid hemorrhage reduced MAP to 55 mm Hg (time interval of zero [T0]) which was maintained at that level for 30 minutes (until T30). Subsequently, over a 5-minute interval (T30-T35), one of the four randomly assigned resuscitation fluids was infused. Data were collected at baseline; after subdural balloon inflation; at T0, T30, T35, and 30-minute intervals thereafter for 2 hours (T65, T95, T125, and T155). CBF and ICP were compared using repeat-measure ANOVA. Cerebral blood flow was greater at T35 in the HS and HS/HES groups than in the HES group (P = .025). In the SAL group, ICP increased significantly from T0 to T35, remaining unchanged thereafter. At T35, ICP in the HS group was significantly lower than in the SAL group (P < .05) but subsequently increased. ICP in the HS/HES group exceeded that in all other groups at T95 and T125 (P < .05). After a severe reduction in cerebral perfusion pressure (CPP), HS solutions (both HS and HS/HES) were associated with a delayed rise in ICP and did not improve global forebrain CBF in comparison with conventional saline solutions.

Impairment of cingulothalamic learning-related neuronal coding in rabbits exposed to cocaine in utero: general and sex-specific effects

Neuronal activity was recorded in the cingulate cortex and the limbic thalamus in Dutch-belted rabbits (Oryctolagus cuniculus) exposed to cocaine (8 mg/kg/day i.v.) or saline in utero during acquisition and reversal learning of a discriminative avoidance response. Anterior cingulate cortical excitatory training-induced activity (TIA) was attenuated in cocaine-exposed female rabbits during acquisition and reversal learning, but only during reversal learning in male rabbits. Posterior cingulate cortical excitatory TIA was lessened in cocaine-exposed rabbits during acquisition, whereas discrimination between the positive and negative cues was enhanced. Neuronal firing was attenuated in the anterior ventral thalamus in cocaine-exposed rabbits during acquisition and reversal learning. Behavioral learning was normal in cocaine-exposed rabbits. Other data suggest that rabbits exposed to cocaine in utero exhibit a learning deficit when trained with nonsalient cues.

Temporary vascular occlusion during cerebral aneurysm surgery

Temporary artery occlusion is an effective way to reduce the detrimental effects of intraoperative aneurysm rupture and to facilitate aneurysm dissection. The major risk incurred is of cerebral infarction. Dilemmas in the use of this technique include the amount of time that arterial flow may be interrupted safely and whether or not there is benefit to intermittent reperfusion. Protocol for the use of temporary occlusion is described.

Neurocytoma presenting with intraparenchymal cerebral hemorrhage

Neurocytomas are uncommon intracranial neoplasms that have only recently been characterized pathologically. Neurocytomas are histologically benign neoplasms that are often quite large when diagnosed, and previous reports have commonly described presentation with mass effect or cerebrospinal fluid outflow obstruction. We describe the first case of neurocytoma presenting with intraparenchymal cerebral hemorrhage.

Direct selection of conserved cDNAs from the DiGeorge critical region: isolation of a novel CDC45-like gene

We have used a modified direct selection technique to detect transcripts that are both evolutionary conserved and developmentally expressed. The enrichment for homologous mouse cDNAs by use of human genomic DNA as template is shown to be an efficient and rapid approach for generating transcript maps. Deletions of human 22q11 are associated with several clinical syndromes, with overlapping phenotypes, for example, velocardiofacial syndrome (VCFS) and DiGeorge syndrome (DGS). A large number of transcriptional units exist within the defined critical region, many of which have been identified previously by direct selection. However, no single obvious candidate gene for the VCFS/DGS phenotype has yet been found. Our technique has been applied to the DiGeorge critical region and has resulted in the isolation of a novel candidate gene, Cdc45l2, similar to yeast Cdc45p. [The sequence data described in this paper have been submitted to the EMBL data library under accession nos. AJ0223728 and AF0223729.]

Ethanol alters brain phospholipid levels which correlate with altered brain morphology

The effects of embryonic exposure on brain phospholipid levels were studied by injecting various concentrations of ethanol into fertile chicken eggs at 0 days of development. At 18 days of development, the levels of total phospholipids and various phospholipid classes were assayed in brain tissue and correlated to neuron densities within the cerebral hemispheres and the optic lobes. Although ethanol concentrations ranging from 0 to 3700 microns/Kg egg wt. failed to influence either total brain weight or total brain phospholipid levels, ethanol-induced changes in the levels of individual phospholipid classes were observed. When injected with 7 microns of ethanol/Kg egg wt., a 2- to 3-fold increase in brain phosphatidylethanolamine (PE) levels were observed with reduced levels of brain phosphatidylcholine (PC) and brain sphingomyelin (SP). When injected with 74 microns of ethanol/Kg egg wt., ethanol-induced increases in brain phosphatidylserine (PS) and PE were observed with ethanol-induced decreases in brain PC and SP. Cell fractionation studies demonstrated ethanol-induced increases in brain PE and PS and ethanol-induced decreases in brain PC and SP in nuclear, mitochondrial, and microsomal membranes. These ethanol-induced alterations in brain phospholipid profiles correlated with ethanol-induced reductions in neuron densities within the cerebral hemispheres and optic lobes.

Brain attack. The emergent management of hypertensive hemorrhage

Intracerebral hemorrhage (ICH) accounts for one half of stroke-related deaths, with hypertensive hemorrhage being the primary etiology. The evolution of minimally invasive devices for removal of ICHs, and the earlier delivery of patients for medical attention may have a great impact on the management of hypertensive hemorrhage.

Mortality rates, hospital length of stay, and the cost of treating subarachnoid hemorrhage in older patients: institutional and geographical differences

The risk of disability and death and the cost of medical care are particularly high for patients with aneurysmal subarachnoid hemorrhage (SAH) who are 65 years of age or older. A retrospective analysis of 47,408 Medicare patients treated over an 8-year period was performed to determine whether a relationship exists between the mortality rate and surgical volume for older patients with SAH. The mortality rate, length of stay in the hospital, and cost of treatment for patients with SAH in California and New York state were also compared. The mortality rate was 14.3% for patients with SAH who were 65 years old or older and who were treated surgically in hospitals in which an average of five or more craniotomies were performed per year; in hospitals averaging between one and five craniotomies annually the mortality rate was 18.4%; and in those averaging less than one such operation per year the rate was 20.5% (trend p = 0.01). There was no difference in the mortality rate for patients in California versus the rate for those in New York. Surgically and medically treated patients, respectively, left the hospital an average of 6.7 and 5.1 days sooner in California than in New York. The unadjusted average reimbursement from Medicare to hospitals for surgically treated patients averaged $1468 more in New York than in California (p < 0.0001), but was equivalent for medically treated patients in the two states. The mortality rate in older patients who are treated surgically for SAH may be inversely correlated with the annual number of craniotomies performed for SAH in patients 65 years of age or older at a given institution. Hospital stays for patients with SAH are significantly shorter in California than in New York.

Mortality rates, hospital length of stay, and the cost of treating subarachnoid hemorrhage in older patients: institutional and geographical differences

The risk of disability and death and the cost of medical care are particularly high for patients with aneurysmal subarachnoid hemorrhage (SAH) who are 65 years of age or older. A retrospective analysis of 47,408 Medicare patients treated over an 8-year period was performed to determine whether a relationship exists between the mortality rate and surgical volume for older patients with SAH. The mortality rate, length of stay in the hospital, and cost of treatment for patients with SAH in California and New York were also compared. The mortality rate was 14.3% for patients with SAH who were 65 years old or older and who were treated surgically in hospitals in which an average of five or more craniotomies were performed per year; in hospitals averaging between one and five craniotomies annually the mortality rate was 18.4%; and in those averaging less than one such operation per year the rate was 20.5% (trend p = 0.01). There was no difference in the mortality rate for patients in California versus the rate for those in New York. Surgically and medically treated patients, respectively, left the hospital an average of 6.7 and 5.1 days sooner in California than in New York. The unadjusted average reimbursement from Medicare to hospitals for surgically treated patients averaged $1468 more in New York than in California (p < 0.0001), but was equivalent for medically treated patients in the two states. The mortality rate in older patients who are treated surgically for SAH may be inversely correlated with the annual number of craniotomies performed for SAH in patients 65 years of age or older at a given institution. Hospital stays for patients with SAH are significantly shorter in California than in New York.

Temporary vessel occlusion during intracranial aneurysm repair

Any method that decreases the risk of intraoperative rupture should improve outcome if complications associated with its use do not negate positive effect. If application time is limited and a form of cerebral protection and appropriate monitoring of cerebral function are used, temporary clip application may meet these requirements. The efficacy of temporary occlusion as an adjunct to aneurysm clipping may be limited by technical considerations with respect to regional anatomy, aneurysm size, and aneurysm consistency. In areas of limited access, positioning proximal clips may not be feasible. The use of endovascular techniques of balloon occlusion may provide proximal control in these situations (9, 106). The decision to use total circulatory arrest and profound hypothermia, as opposed to temporary clip application, remains largely a matter of the surgeon's judgment. The role of proximal parent vessel ligation must also be considered in the decision-making process regarding the treatment of giant or technically difficult aneurysms (114). Further refinements in cerebral monitoring that can accurately reflect intracellular processes in all territories affected by the application of temporary clips or balloon occlusion and development of more effective forms of cerebral protection may permit safer use of this technique. An adequately controlled clinical trial of temporary occlusion with or without putative "cerebral protection" is needed to confirm the efficacy of this technique.

Good clinical outcome in a patient with a large CT scan hypodensity treated with intra-arterial urokinase after an embolic stroke

Hypodense regions demonstrated by CT within 6 hours of the onset of stroke may reflect irreversibly damaged tissue, and some have suggested that patients with such findings should be spared the risks of thrombolytic therapy since they are unable to benefit from it. We report here a patient with a low-density area demonstrated by CT less than 6 hours after onset of symptoms who improved dramatically after successful intra-arterial thrombolysis.