Evolution of surgical attitudes to paediatric thalamic tumours: the alder hey experience

PURPOSE

Attitudes to surgery for paediatric thalamic tumours have evolved due to improved preoperative imaging modalities and the advent of intraoperative MRI (iMRI) as well as enhanced understanding of tumour biology. We review the developments in our local practice over the last three decades with particular attention to the impact of iMRI.

METHODS

We identified all paediatric patients from a prospectively maintained neuro-oncology database who received surgery for a thalamic tumour (n = 30). All children were treated in a single UK tertiary paediatric neurosurgery centre between January 1991 and June 2020. Twenty patients underwent surgical resection, the remainder (10) undergoing biopsy only. Pre-operative surgical intent (biopsy versus debulking, near-total resection, or complete resection) as well as the use of iMRI were prospectively recorded. Complications recorded in clinical documentation between postoperative days 0 and 30 were retrospectively graded using a modified version of the Clavien Dindo scale. The extent of resection with respect to the pre-determined surgical aim was also recorded. Data on patient survival and disease progression status were obtained retrospectively.

RESULTS

In our series, there were 42 procedures (25 craniotomies, 17 biopsies) performed on 30 patients (17 male, with a median age of 8 at surgery). Of the 25 surgical resections performed, complete resection was achieved in 9 (36%), near-total resection in 10 (40%), and limited debulking in 6 (24%). The predetermined surgical aim was achieved or exceeded in 91.3% of cases. The proportion of craniotomies for which substantial resection was achieved, increased from 37.5 to 94.2% with use of iMRI (p = 0.014). Surgical morbidity was not associated with greater extent of surgical resection. High-grade histology is identified as the only independent significant factor influencing overall survival as calculated by Cox proportional hazards model (p = 0.006).

CONCLUSION

We note a significant change in the rate and extent of attempted resection of paediatric thalamic tumours that has developed over the last 3 decades. Use of iMRI is associated with a significant increase in substantial tumour resection surgeries. This is not associated with any significant level of surgical morbidity. Improvements in pre- and intra-operative imaging alongside better understanding of tumour biology facilitate patient selection and a surgically more aggressive approach in selected cases whilst maintaining safety and avoiding operative morbidity.

Reporting morbidity associated with pediatric brain tumor surgery: are the available scoring systems sufficient?

OBJECTIVE

Complications in pediatric neurooncology surgery are seldom and inconsistently reported. This study quantifies surgical morbidity after pediatric brain tumor surgery from the last decade in a single center, using existing morbidity and outcome measures.

METHODS

The authors identified all pediatric patients undergoing surgery for an intracranial tumor in a single tertiary pediatric neurosurgery center between January 2008 and December 2018. Complications between postoperative days 0 and 30 that had been recorded prospectively were graded using appropriate existing morbidity scales, i.e., the Clavien-Dindo (CD), Landriel, and Drake scales. The result of surgery with respect to the predetermined surgical aim was also recorded.

RESULTS

There were 477 cases (364 craniotomies and 113 biopsies) performed on 335 patients (188 males, median age 9 years). The overall 30-day mortality rate was 1.26% (n = 6), and no deaths were a direct result of surgical complication. Morbidity on the CD scale was 0 in 55.14%, 1 in 10.69%, 2 in 18.66%, 3A in 1.47%, 3B in 11.74%, and 4 in 1.05% of cases. Morbidity using the Drake classification was observed in 139 cases (29.14%). Neurological deficit that remained at 30 days was noted in 8.39%; 78% of the returns to the operative theater were for CSF diversion.

CONCLUSIONS

To the authors' knowledge, this is the largest series presenting outcomes and morbidity from pediatric brain tumor surgery. The mortality rate and morbidity on the Drake classification were comparable to those of published series. An improved tool to quantify morbidity from pediatric neurooncology surgery is necessary.

Does pre-resection endoscopic third ventriculostomy prevent the need for post-resection CSF diversion after pediatric posterior fossa tumor excision? A historical cohort study and review of the literature

OBJECTIVE

Children with posterior fossa tumors (PFTs) may present with hydrocephalus. Persistent (or new) hydrocephalus is common after PFT resection. Endoscopic third ventriculostomy (ETV) is sometimes performed prior to resection to 1) temporize hydrocephalus prior to resection and 2) prophylactically treat post-resection hydrocephalus. The objective of this study was to establish, in a historical cohort study of pediatric patients who underwent primary craniotomy for PFT resection, whether or not pre-resection ETV prevents the need for post-resection CSF diversion to manage hydrocephalus.

METHODS

The authors interrogated their prospectively maintained surgical neuro-oncology database to find all primary PFT resections from a single tertiary pediatric neurosurgery unit. These data were reviewed and supplemented with data from case notes and radiological review. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) score was retrospectively calculated for all patients. The primary outcome was the need for any form of postoperative CSF diversion within 6 months of PFT resection (including ventriculoperitoneal shunting, ETV, external ventricular drainage [EVD], and lumbar drainage [LD]). This was considered an ETV failure in the ETV group. The secondary outcomes were time to CSF diversion, shunt dependence at 6 months, and complications of ETV. Statistical analysis was done in RStudio, with significance defined as p < 0.05.

RESULTS

A total of 95 patients were included in the study. There were 28 patients in the ETV group and 67 in the non-ETV group. Patients in the ETV group were younger (median age 5 vs 7 years, p = 0.04) and had more severe preoperative hydrocephalus (mean frontal-occipital horn ratio 0.45 vs 0.41 in the non-ETV group, p = 0.003) and higher mCPPRH scores (mean 4.42 vs 2.66, p < 0.001). The groups were similar in terms of sex and tumor histology. The overall rate of post-resection CSF diversion of any kind (shunt, repeat ETV, LD, or EVD) in the entire cohort was 25.26%. Post-resection CSF diversion was needed in 32% of patients in the ETV group and in 22% of the patients in the non-ETV group (p > 0.05). Shunt dependence at 6 months was seen in 21% of the ETV group and 16% of the non-ETV group (p > 0.05). The median time to ETV failure was 9 days. ETV failure correlated with patients with ependymoma (p = 0.02). Children who had ETV failure had higher mCPPRH scores than the ETV success group (5.67 vs 3.84, p = 0.04).

CONCLUSIONS

Pre-resection ETV did not reliably prevent the need for post-resection CSF diversion. ETV was more likely to fail in children with ependymoma and those with higher mCPPRH scores. Based on the findings of this study, the authors will change the practice at their institution; pre-resection ETV will now be performed based on a newly defined protocol.

FP2-3 Ten years of paediatric neuro-oncology surgery: quantifying and predicting complications after surgery for intracranial tumour excision

Objectives

To measure complications of paediatric neurooncology surgery using the Clavien Dindo grading scale, and identify predictors of surgical morbidity.

Design

Retrospective review of prospectively collected data.

Subjects

All paediatric patients treated with craniotomy for excision of intracranial tumour between 2008 and 2017 in a single tertiary paediatric neurosurgery centre.

Methods

Demographics, surgical details and perioperative complications were prospectively recorded between 0 and 30 days post operatively. These were retrospectively graded using the CD scale. Data analysis was done in R using logistic regression. Significance was defined as p<0.05

Results

Between 3/1/2008 and 21/12/2017 there were 322 operations, on 254 patients (142 Male). Median age at surgery was 9 years (IQR 4–13 years). 48% were without complication on the CD scale. Maximum CD grade complication for each procedure was 1 in 11%, 2 in 19%, 3A in 2%, 3B in 14%, and 4 in 0.6% of operations. 30 day mortality was 0.9%. CD grade of 3B or over was associated with infratentorial tumours (OR 2.24; CI 1.10–4.68; p=0.004) and WHO grade III tumours (OR 4.12; CI 1.56–10.86; p=0.028).

Conclusions

Complications in paediatric neurooncology surgery are common overall, but our results are favourable in comparison to the literature. The CD scale has limitations in neurosurgery but gives insight into the health economic impact of complications. Infratentorial tumours, and WHO grade III tumours were associated with increased morbidity.

Comparison of clinical outcomes in anterior cervical discectomy versus foraminotomy for brachialgia

AIM

The choice between anterior cervical discectomy & fusion (ACD) or posterior cervical foraminotomy (PCF) for the treatment of cervical brachialgia is controversial. This study aimes to compare clinical outcomes between these two operative inteventions for brachialgia.

METHODS

Retrospective review of prospectively collected data was performed. Patients receiving a primary ACD or PCF to treat brachialgia, in a single tertiary neurosurgical unit were included. Surgical details, and patient reported outcomes (COMI-Neck questionnaire) were extracted from a prospectively maintained spinal procedure database. Minimum clinically important difference (MCID) was defined as a change in COMI score of -2 at 12 months. The student t-test, Chi-square test, and linear regression were used to compare groups.

RESULTS

Between June 2011 ad February 2016 there were 634 ACD procedures (Median age 49; 321 Male), and 54 PCF procedures (Median age 50; 37 Male) perfomed for brachialgia. Age, ASA and pre-operative COMI were similar between the groups (p > .05). Complete outcome data was recorded at twelve months in 312 ACD and 36 PCF patients. Both ACD and PCF were associated with an improvement in COMI at 3 and 12 months (all p < .01). Mean change in COMI at 3 months was -2.38 for ACD, versus -2.31 for PCF (p = .88); at twelve months it was -2.94 for ACD, versus -2.67 for PCF (p = .55). MCID was seen in 59% of ACD cases, versus 58% of PCF cases at twelve months (p = .91).

CONCLUSION

There was no significant difference between outcomes in the ACD and PCF groups. This is supportive of published literature. The proposed multicenter RCTs may inform further.

Posterior Inferior Cerebellar Artery/Vertebral Artery Subarachnoid Hemorrhage: A Comparison of Saccular vs Dissecting Aneurysms

BACKGROUND

Two distinct categories of aneurysms are described in relation to the posterior inferior cerebellar artery (PICA) and vertebral artery (VA): saccular (SA) and dissecting (DA) types. This distinction is often unrecognized because abnormalities here are uncommon and most studies are small.

OBJECTIVE

To determine if there are any differences in the clinical presentation, in-hospital course, or outcomes in patients with DA vs SA of the PICA or VA.

METHODS

Thirty-eight patients with a VA or PICA aneurysm were identified from a departmental subarachnoid hemorrhage database and categorized into DA or SA types. Prospectively collected demographic and outcome data (length of stay, discharge Glasgow Outcome Score) were supplemented by abstracting records for procedural data (extraventricular drain [EVD], ventriculoperitoneal [VP] shunt, tracheostomy, and nasogastric feeding). Univariate, binary logistic regression, and Cox regression analysis was used to compare patients with SA vs DA.

RESULTS

Three aneurysms related to arteriovenous malformation were excluded. Five patients were conservatively managed. Of the 30 treated cases, more patients with a DA presented in poor grade (6/13 vs 2/17 SA; P = .035). More DA patients required an EVD (85% vs 29%; P = .003), VP shunt (54% vs 6%; P = .003), tracheostomy (46% vs 6%; P < .01), and nasogastric feeding (85% vs 35%; P = .007). The median length of stay (41 vs 17 d, P < .001) was longer, and the age and injury severity adjusted odds of discharge home were significantly lower in the DA group (P = .008). Thirty-day mortality was not significantly different (23% of DA vs 24% of SA; P = .2).

CONCLUSION

The presentation, clinical course, and outcomes differ in patients with DA vs SA of the PICA and VA.

Pediatric Central Nervous System Tumors: State-of-the-Art and Debated Aspects

Pediatric neuro-oncology surgery continues to progress in sophistication, largely driven by advances in technology used to aid the following aspects of surgery: operative planning (advanced MRI techniques including fMRI and DTI), intraoperative navigation [preoperative MRI, intra-operative MRI (ioMRI) and intra-operative ultrasound (ioUS)], tumor visualization (microscopy, endoscopy, fluorescence), tumor resection techniques (ultrasonic aspirator, micro-instruments, micro-endoscopic instruments), delineation of the resection extent (ioMRI, ioUS, and fluorescence), and intraoperative safety (neurophysiological monitoring, ioMRI). This article discusses the aforementioned technological advances, and their multimodal use to optimize safe pediatric neuro-oncology surgery.

Diet-induced obesity causes visceral, but not subcutaneous, lymph node hyperplasia via increases in specific immune cell populations

OBJECTIVES

The spatial proximity of adipose depots to secondary lymph nodes allows a unique relation between the two systems. Obesity, predominately visceral adiposity, links to numerous diseases; hence, we postulate that secondary lymphatics within this region contributes to disease risk.

MATERIAL AND METHODS

Male C57BL/6 mice were fed standard CHOW (18% kcal fat) or Western diet (45% kcal fat) for 7 weeks. Visceral and subcutaneous lymph nodes and associated adipose depots they occupy were excised. Lymph node morphology and resident immune cell populations were characterized via histopathology, immunofluorescence and flow cytometry. Adipose tissue immune cell populations were also characterized.

RESULTS

Obesity caused lymph node expansion, increased viable cell number and deviations in immune cell populations. These alterations were exclusive to visceral lymph nodes. Notably, pro-inflammatory antigen presenting cells and regulatory T cells increased in number in the visceral lymph node. Obesity, however, reduced T regulatory cells in visceral lymph nodes. The visceral adipose depot also had greater reactivity towards HFD than subcutaneous, with a greater percent of macrophages, dendritic and CD8⁺ T cells. Immune cell number, in both the visceral and subcutaneous, however decreased as adipose depots enlarged.

CONCLUSION

Overall, HFD has a greater influence on visceral cavity than the subcutaneous. In the visceral lymph node, but not subcutaneous, HFD-induced obesity decreased cell populations that suppressed immune function while increasing those that regulate/activate immune response.

Posterior Inferior Cerebellar Artery/Vertebral Artery Subarachnoid Hemorrhage: A Comparison of Saccular vs Dissecting Aneurysms

BACKGROUND

Two distinct categories of aneurysms are described in relation to the posterior inferior cerebellar artery (PICA) and vertebral artery (VA): saccular (SA) and dissecting (DA) types. This distinction is often unrecognized because abnormalities here are uncommon and most studies are small.

OBJECTIVE

To determine if there are any differences in the clinical presentation, in-hospital course, or outcomes in patients with DA vs SA of the PICA or VA.

METHODS

Thirty-eight patients with a VA or PICA aneurysm were identified from a departmental subarachnoid hemorrhage database and categorized into DA or SA types. Prospectively collected demographic and outcome data (length of stay, discharge Glasgow Outcome Score) were supplemented by abstracting records for procedural data (extraventricular drain [EVD], ventriculoperitoneal [VP] shunt, tracheostomy, and nasogastric feeding). Univariate, binary logistic regression, and Cox regression analysis was used to compare patients with SA vs DA.

RESULTS

Three aneurysms related to arteriovenous malformation were excluded. Five patients were conservatively managed. Of the 30 treated cases, more patients with a DA presented in poor grade (6/13 vs 2/17 SA; P = .035). More DA patients required an EVD (85% vs 29%; P = .003), VP shunt (54% vs 6%; P = .003), tracheostomy (46% vs 6%; P &lt; .01), and nasogastric feeding (85% vs 35%; P = .007). The median length of stay (41 vs 17 d, P &lt; .001) was longer, and the age and injury severity adjusted odds of discharge home were significantly lower in the DA group (P = .008). Thirty-day mortality was not significantly different (23% of DA vs 24% of SA; P = .2).

CONCLUSION

The presentation, clinical course, and outcomes differ in patients with DA vs SA of the PICA and VA.

Inhibition of adipose tissue PPARγ prevents increased adipocyte expansion after lipectomy and exacerbates a glucose-intolerant phenotype

OBJECTIVES

Adipose tissue plays a fundamental role in glucose homeostasis. For example, fat removal (lipectomy, LipX) in lean mice, resulting in a compensatory 50% increase in total fat mass, is associated with significant improvement in glucose tolerance. This study was designed to further examine the link between fat removal, adipose tissue compensation and glucose homeostasis using a peroxisome proliferator-activated receptor γ (PPAR γ; activator of adipogenesis) knockout mouse.

MATERIAL AND METHODS

The study involved PPARγ knockout (FKOγ) or control mice (CON), subdivided into groups that received LipX or Sham surgery. We reasoned that as the ability of adipose tissue to expand in response to LipX would be compromised in FKOγ mice, so would improvements in glucose homeostasis.

RESULTS

In CON mice, LipX increased total adipose depot mass (~60%), adipocyte number (~45%) and changed adipocyte distribution to smaller cells. Glucose tolerance was improved (~30%) in LipX CON mice compared to Shams. In FKOγ mice, LipX did not result in any significant changes in adipose depot mass, adipocyte number or distribution. LipX FKOγ mice were also characterized by reduction of glucose tolerance (~30%) compared to shams.

CONCLUSIONS

Inhibition of adipose tissue PPARγ prevented LipX-induced increases in adipocyte expansion and produced a glucose-intolerant phenotype. These data support the notion that adipose tissue expansion is critical to maintain and/or improvement in glucose homeostasis.

The role of visceral and subcutaneous adipose tissue fatty acid composition in liver pathophysiology associated with NAFLD

Visceral adiposity is associated with type-2-diabetes, inflammation, dyslipidemia and non-alcoholic fatty liver disease (NAFLD), whereas subcutaneous adiposity is not. We hypothesized that the link between visceral adiposity and liver pathophysiology involves inherent or diet-derived differences between visceral and subcutaneous adipose tissue to store and mobilize saturated fatty acids. The goal of the present study was to characterize the fatty acid composition of adipose tissue triglyceride and portal vein fatty acids in relation to indices of liver dysregulation. For 8 weeks rats had free access to control (CON; 12.9% corn/safflower oil; 3.6 Kcal/g), high saturated fat (SAT; 45.2% cocoa butter; 4.5 Kcal/g) or high polyunsaturated fat (PUFA; 45.2% safflower oil; 4.5 Kcal/g) diets. Outcome measures included glucose tolerance, visceral and subcutaneous adipose tissue triglyceride, liver phospholipids and plasma (portal and systemic) free fatty acid composition, indices of inflammation and endoplasmic reticulum stress in the liver and adipose tissue depots and circulating adipo/cytokines. Hepatic triglycerides were significantly increased in both high fat diet groups compared to control and were significantly higher in PUFA compared to SAT. Although glucose tolerance was not different among diet groups, SAT increased markers of inflammation and ER stress in the liver and both adipose tissue depots. Fatty acid composition did not differ among adipose depots or portal blood in any dietary group. Overall, these data suggest that diets enriched in saturated fatty acids are associated with liver inflammation, ER stress and injury, but that any link between visceral adipose tissue and these liver indices does not involve selective changes to fatty acid composition in this depot or the portal vein.

Lower body adipose tissue removal decreases glucose tolerance and insulin sensitivity in mice with exposure to high fat diet

It has been postulated that the protective effects of lower body subcutaneous adipose tissue (LBSAT) occur via its ability to sequester surplus lipid and thus serve as a "metabolic sink." However, the mechanisms that mediate this protective function are unknown thus this study addresses this postulate. Ad libitum, chow-fed mice underwent Sham-surgery or LBSAT removal (IngX, inguinal depot removal) and were subsequently provided chow (Chow; typical adipocyte expansion) or high fat diet (HFD; enhanced adipocyte expansion) for 5 weeks. Primary outcome measures included glucose tolerance and subsequent insulin response, muscle insulin sensitivity, liver and muscle triglycerides, adipose tissue gene expression, and circulating lipids and adipokines. In a follow up study the consequences of extended experiment length post-surgery (13 wks) or pre-existing glucose intolerance were examined. At 5 wks post-surgery IngX in HFD-fed mice reduced glucose tolerance and muscle insulin sensitivity and increased circulating insulin compared with HFD Sham. In Chow-fed mice, muscle insulin sensitivity was the only measurement reduced following IngX. At 13 wks circulating insulin concentration of HFD IngX mice continued to be higher than HFD Sham. Surgery did not induce changes in mice with pre-existing glucose intolerance. IngX also increased muscle, but not liver, triglyceride concentration in Chow- and HFD-fed mice 5 wks post-surgery, but chow group only at 13 wks. These data suggest that the presence of LBSAT protects against triglyceride accumulation in the muscle and HFD-induced glucose intolerance and muscle insulin resistance. These data suggest that lower body subcutaneous adipose tissue can function as a "metabolic sink."

Subcutaneous Adipose Tissue Transplantation in Diet-Induced Obese Mice Attenuates Metabolic Dysregulation While Removal Exacerbates It

Adipose tissue distribution is an important determinant of obesity-related comorbidities. It is well established that central obesity (visceral adipose tissue accumulation) is a risk factor for many adverse health consequences such as dyslipidemia, insulin resistance, and type-2-diabetes. We hypothesize that the metabolic dysregulation that occurs following high fat diet-induced increases in adiposity are due to alterations in visceral adipose tissue function which influence lipid flux to the liver via the portal vein. This metabolic pathology is not exclusively due to increases in visceral adipose tissue mass but also driven by intrinsic characteristics of this particular depot. In Experiment 1, high fat diet (HFD)-induced obese control (abdominal incision, but no fat manipulation) or autologous (excision and subsequent relocation of adipose tissue) subcutaneous tissue transplantation to the visceral cavity. In Experiment 2, mice received control surgery, subcutaneous fat removal, or heterotransplantation (tissue from obese donor) to the visceral cavity. Body composition analysis and glucose tolerance tests were performed 4 weeks postsurgery. Adipose mass and portal adipokines, cytokines, lipids, and insulin were measured from samples collected at 5 weeks postsurgery. Auto- and heterotransplantation in obese mice improved glucose tolerance, decreased systemic insulin concentration, and reduced portal lipids and hepatic triglycerides compared with HFD controls. Heterotransplantation of subcutaneous adipose tissue to the visceral cavity in obese mice restored hepatic insulin sensitivity and reduced insulin and leptin concentrations to chow control levels. Fat removal, however, as an independent procedure exacerbated obesity-induced increases in leptin and insulin concentrations. Overall subcutaneous adipose tissue protects against aspects of metabolic dysregulation in obese mice. Transplantation-induced improvements do not occur via enhanced storage of lipid in adipose tissue, however, altered hepatic lipid regulation may play a contributory role.

Cannabinoid receptor 1 (CB1) antagonism enhances glucose utilisation and activates brown adipose tissue in diet-induced obese mice

AIMS/HYPOTHESIS

We examined the physiological mechanisms by which cannabinoid receptor 1 (CB1) antagonism improves glucose metabolism and insulin sensitivity independent of its anorectic and weight-reducing effects, as well as the effects of CB1 antagonism on brown adipose tissue (BAT) function.

METHODS

Three groups of diet-induced obese mice received for 1 month: vehicle; the selective CB1 antagonist SR141716; or vehicle/pair-feeding. After measurements of body composition and energy expenditure, mice underwent euglycaemic-hyperinsulinaemic clamp studies to assess in vivo insulin action. In separate cohorts, we assessed insulin action in weight-reduced mice with diet-induced obesity (DIO), and the effect of CB1 antagonism on BAT thermogenesis. Surgical denervation of interscapular BAT (iBAT) was carried out in order to study the requirement for the sympathetic nervous system in mediating the effects of CB1 antagonism on BAT function.

RESULTS

Weight loss associated with chronic CB1 antagonism was accompanied by increased energy expenditure, enhanced insulin-stimulated glucose utilisation, and marked activation of BAT thermogenesis. Insulin-dependent glucose uptake was significantly increased in white adipose tissue and BAT, whereas glycogen synthesis was increased in liver, fat and muscle. Despite marked weight loss in the mice, SR141716 treatment did not improve insulin-mediated suppression of hepatic glucose production nor increase skeletal muscle glucose uptake. Denervation of iBAT blunted the effect of SR141716 on iBAT differentiation and insulin-mediated glucose uptake.

CONCLUSIONS/INTERPRETATION

Chronic CB1 antagonism markedly enhances insulin-mediated glucose utilisation in DIO mice, independent of its anorectic and weight-reducing effects. The potent effect on insulin-stimulated BAT glucose uptake reveals a novel role for CB1 receptors as regulators of glucose metabolism.

Transplantation of non-visceral fat to the visceral cavity improves glucose tolerance in mice: investigation of hepatic lipids and insulin sensitivity

AIMS/HYPOTHESIS

Intra-abdominal transplantation of non-visceral adipose tissue in rodents, simulating increased abdominal fat in obesity, paradoxically improves glucose tolerance and insulin sensitivity. We hypothesised that this improvement is due to transplant-induced enhanced uptake of fatty acids by adipose tissue, thus reducing fatty acid flux into, and triacylglycerol storage in, the liver.

METHODS

In Experiment 1, mice were sham-operated or received heterologous epididymal white adipose tissue (WAT; EWAT) or visceral WAT (VWAT) transplantation to the portal and splanchnic circulation regions in the visceral cavity. In Experiment 2, inguinal WAT (IWAT) or EWAT was removed and subsequently transplanted to the visceral cavity of the same mouse (autotransplant). IWAT and EWAT autotransplants were repeated in Experiment 3 and compared with heterotransplants.

RESULTS

Heterotransplantation of VWAT did not alter glucose tolerance, whereas auto- or hetero-transplantation of EWAT or IWAT significantly improved glucose tolerance. Transplantation-induced improvements in glucose tolerance 4 weeks after surgery coincided with decreased liver triacylglycerol, decreased portal plasma lipids and increased hepatic insulin sensitivity. By 8 weeks, these changes were apparent only in mice with autotransplantation. Heterologous EWAT transplantation-induced glucose improvement persisted without altered liver metabolism.

CONCLUSIONS/INTERPRETATION

Increases in visceral fat, via transplantation of visceral or non-visceral adipose tissue, is not a major risk factor for glucose intolerance. In fact, there are dynamic metabolic improvements following transplantation that include decreased portal lipids and improved liver metabolism, but these improvements are transient under certain circumstances.

Insulin and the constituent branches of the hepatic vagus interact to modulate hypothalamic and limbic neuropeptide mRNA expression differentially

Insulin and signalling through the vagus nerve act in concert to regulate metabolic homeostasis and ingestive behaviour. Our previous studies using streptozotocin (STZ)-diabetic rats have shown that hepatic branch vagotomy (HV), gastroduodenal branch vagotomy (GV) and capsaicin treatment of the common hepatic branch that selectively destroys afferent fibres (CapV), all promote lard, but not total, caloric intake to levels similar to those achieved with insulin treatment. Because hypothalamic and limbic mRNA expression of neuropeptides linked to energy balance is altered by STZ-diabetes and HV, we examined the role(s) of insulin and the common hepatic and gastroduodenal branches of the vagus nerve and hepatic afferent fibres in the regulation of these neuropeptides in rats with high, steady-state corticosterone levels. STZ-diabetic rats were prepared with osmotic minipumps containing either saline or insulin and were compared with nondiabetic counterparts: half of each group received a vagal manipulation, the other half were sham operated. Five days after surgery, rats were offered the choice of lard and chow to consume for another 5 days, when brains were collected and processed for in situ hybridisation. Paraventricular nucleus corticotrophin-releasing factor (CRF) mRNA was elevated by STZ treatment, an effect prevented by either insulin treatment or GV. By contrast, CRF mRNA expression in the central nucleus of the amygdala and bed nuclei of the stria terminalis was unaffected by STZ treatment, but HV and CapV manipulations elevated expression in the nondiabetic, but not STZ-diabetic groups. Arcuate nucleus neuropeptide Y, but not pro-opiomelanocortin, mRNA expression was elevated by STZ treatment and all vagal manipulations; however, exogenous insulin treatment failed to prevent this, in keeping with their previously documented elevated caloric intake. These results strongly suggest that the gastroduodenal branch and hepatic branch proper, which merge to form the common hepatic branch, differentially interact with prevailing insulin levels to regulate hypothalamic and limbic neuropeptide mRNA expression.

Mapping brain c-Fos immunoreactivity after insulin-induced voluntary lard intake: insulin- and lard-associated patterns

In addition to the inhibitory role of central insulin on food intake, insulin also acts to promote lard intake. We investigated the neural pathways involved in this facet of insulin action. Insulin or saline was infused into either the superior mesenteric or right external jugular veins of streptozotocin-diabetic rodents with elevated steady-state circulating corticosterone concentrations. After postsurgical recovery, rats were offered the choice of chow or lard to eat. Irrespective of the site of venous infusion, insulin increased lard and decreased chow intake. After 4 days, lard was removed for 8 h. On return for 1 h, only insulin infused into the superior mesenteric vein resulted in lard intake. This facilitated distinction between the effects of circulating insulin concentrations (similar in the two insulin-infused groups) and lard ingestion on the patterns of c-Fos(+) cells in the brain, termed insulin- and lard-associated patterns, respectively. Insulin-associated changes in c-Fos(+) cell numbers were evident in the arcuate nucleus, bed nucleus of the stria terminalis and substantia nigra pars compacta, concomitant with elevated leptin levels and reduced chow intake. Lard-associated changes in c-Fos(+) cell numbers were observed in the nucleus of the tractus solitarius, lateral parabrachial nucleus, central nucleus of the amygdala, ventral tegmental area, nucleus accumbens shell and the prefrontal cortex, and were associated with lower levels of triglycerides and free fatty acids. The anterior paraventricular thalamic nucleus exhibited both patterns. These data collectively fit into a framework for food intake and reward and provide targets for pharmacological manipulation to influence the choice of food intake.

Intravascular ultrasound diagnosis of cystic adventitial degeneration of the popliteal artery: a case report

The diagnosis of cystic adventitial degeneration (CAD) is difficult. We present the first case in which intravascular ultrasound (IVUS) correctly identified CAD of the popliteal artery when duplex sonography and angiography were inconclusive.

Ultrasound thrombolysis for the treatment of thrombotic occlusion of degenerated saphenous vein grafts

Despite improvements in catheter-based revascularization outcomes, coronary interventionalists face difficult challenges in the treatment of the thrombus-laden coronary lesion. In this report, we describe the use of the Acolysis device, which utilizes high-frequency (41.9 kHz) ultrasonic energy to vibrate a small metal tip at the end of a 4.5 Fr catheter to treat two thrombotically occluded saphenous vein grafts in two patients. In both cases, the Acolysis device provided normalization of flow with angiographically evident dissolution of thrombus and excellent acute angiographic and clinical results. We conclude that in these two selected cases the Acolysis device was used safely and effectively for thrombus debulking as an adjunct to stenting in diseased saphenous vein bypass grafts.

Reversal of "no reflow" during vein graft stenting using high velocity boluses of intracoronary adenosine

Slow or no reflow is a serious problem complicating catheter-based revascularization of degenerated saphenous vein bypass grafts. We examined the efficacy of rapidly delivered, high-velocity injections of intracoronary adenosine to reverse 11 slow-flow events complicating stenting of diseased bypass grafts. Ten of 11 events were rapidly improved to TIMI 3 flow by this technique within 3.8+/-1.6 min of the initial adenosine injection. In an ex vivo model, 3-ml syringes created higher peak pressures and velocities than 10- and 20-ml syringes. We conclude that rapid and repeated high-velocity intragraft administration of adenosine is a promising new approach to promptly reverse no-reflow events complicating PTCA and stenting of diseased saphenous vein grafts. Ex vivo studies demonstrate a potentially important mechanical advantage with the use of small syringes for injection. Further randomized studies will be required to better define the mechanism(s) and efficacy of this approach for treating no reflow, including its use in native vessels.

Histopathology of restenosis after stenting of narrowed coronary arteries after cardiac transplantation during the teenage years

This study describes the detailed histopathologic appearance of human coronary arteries at 3 weeks, and 3 and 7 months after stent implantation in a cardiac transplant recipient. There was modest arterial injury associated with stent implantation, and immunocytochemistry staining provided evidence that a proliferative response from the adventitia contributes to neointimal hyperplasia.

Electrophysiologic effects and predictors of success of combination therapy with class Ia and Ib antiarrhythmic drugs for sustained ventricular arrhythmias

Antiarrhythmic drugs remain the first line of therapy in patients with sustained ventricular arrhythmias. Although success with class Ia antiarrhythmic medications has been limited, there is evidence that the addition of a class Ib agent may improve results. A total of 110 consecutive patients referred for electrophysiologic evaluation who had inducible sustained ventricular arrhythmias resistant to a class Ia agent underwent repeat electrophysiologic study after the addition of a class Ib drug. Patients with ejection fraction >40% and ventricular fibrillation inducible in the baseline study had an 80% response rate, whereas those with inducible ventricular tachycardia and ejection fraction < or = 40% responded 11% of the time. Responders demonstrated marked prolongation of ventricular refractoriness and slight shortening of the QRS, whereas nonresponders had QRS prolongation and a more modest increase in ventricular refractoriness. Thus, the efficacy of class Ia/Ib combination therapy in patients with inducible sustained ventricular arrhythmias refractory to a class Ia drugs alone can be predicted by baseline variables. Marked prolongation of ventricular refractoriness in the absence of QRS prolongation appears to be a key factor in the success of this combination.

A pilot study of chronic recombinant interferon-alfa 2a for diabetic proliferative retinopathy: metabolic effects and opthalmologic effects

The objective of this study was to evaluate the metabolic effects and opthalmologic effects of alpha-interferon therapy in diabetes mellitus patients with proliferative diabetic retinopathy (PDR). Three volunteer patients [insulin-dependent diabetes mellitus (IDDM), insulin requiring non-insulin-dependent diabetes mellitus (NIDDM), and maturity onset diabetes of the young (MODY)] threatened with blindness due to progressive PDR were treated with alpha interferon for 4 months and were evaluated at intervals of 1-2 weeks to monitor the drug effects on carbohydrate tolerance and possible beneficial therapeutic effects on the preexisting PDR. Metabolic studies included basal and postsustacal glucose, c-peptide and glucagon, fasting serum cortisol, free fatty acids, growth hormone, insulin-like growth factor-1, and urinary microalbumin excretion. Ophthalmologic studies included visual acuity, slit lamp examination, gonioscopy, fluorescein angiography, and standard colored fundus photographs. In all subjects, hyperglycemia worsened with duration of increasing dosage of interferon therapy, requiring progressively higher daily insulin requirements of 17%-68% above pretreatment values. Lowered levels of stimulated C-peptide were observed in the NIDDM and MODY subjects. The counterregulatory hormones (cortisol, growth hormone, and glucagon) were elevated during the 4 months of interferon therapy. In all subjects, visual acuity appeared to stabilize. No new retinal hemorrhages occurred during the 4 months of interferon administration, although all subjects experienced hemorrhage within 6 weeks of termination of the drug. Although only three subjects were investigated, the 1-2 week frequency of metabolic and opthalmologic studies permit some conclusions. The metabolic effects of alpha interferon in our diabetic subjects were consistent worsening of carbohydrate tolerance associated with impaired beta-cell secretion and increased insulin resistance. The extensive opthalmologic investigation suggested protection from retinal hemorrhage while receiving interferon, but further studies are indicated to validate these proposed and antiangiogenic properties.

Diagnosis and treatment of community-acquired and hospital-acquired pneumonia

The older drugs used to treat pneumonia may still be useful in self-limiting infections. Newer antibiotics--augmented penicillins, trimethoprim-sulfamethoxazole, third-generation cephalosporins, and others--are quite effective, but resistance can be a problem, and some patients cannot tolerate the adverse events associated with these agents. The fluoroquinolones are effective in treating pneumonia because of their broad spectra of activity against gram-negative and gram-positive organisms, including Streptococcus pneumoniae and Haemophilus influenzae. They are rapidly and nearly completely absorbed after oral administration; bioavailability ranges up to 100% for ofloxacin and lomefloxacin. Concentrations attained in lung tissues and sputum generally exceed the minimum inhibitory concentrations for the most common respiratory tract pathogens. The quinolones are also well tolerated; most adverse events are mild and do not lead to discontinuation of therapy. Ciprofloxacin and ofloxacin are available in parenteral as well as oral formulations. The high bioavailability of oral ofloxacin (> 95%) allows a patient to be started on the parenteral form in the hospital and continued taking the oral form at home with no loss of efficacy, but with reduced costs and improved quality of life.

Ceftriaxone in treatment of serious infections. Septicemia

Ceftriaxone is generally recognized as safe and effective when used as a single drug in the therapy of septicemia and other serious infections involving bacteremia in both adults and children. An advantage of ceftriaxone over other third-generation cephalosporins is its long serum half-life, which allows the drug to be given every 12 hours in children or less frequently in adults.

Development and implementation of a comprehensive, criteria-based drug-use review program

A comprehensive drug-use review (DUR) program based on established criteria for use of each drug is described. The DUR program was developed to promote cost-effective drug therapy and satisfy Joint Commission on Accreditation of Hospitals standards for drug-use evaluation. Antibiotic and ambulatory-care drug-use subcommittees composed of physicians, pharmacists, nurses, and clinical laboratory personnel were formed as advisory groups to the pharmacy and therapeutics (P&T) committee. The subcommittees review overall drug-use patterns in their respective areas monthly and investigate the use of specific problem drugs. Drug-use reviews have been facilitated by the implementation of a mandatory antibiotic order form and pharmacy computer systems. Nonformulary drug use is monitored. The procedure for adding drugs to the formulary was modified to require the submission of specific criteria for appropriate drug use; when a drug is added to the formulary, the criteria for use are also adopted. The program has been successful in curtailing inappropriate drug use, reducing drug expenditures, and integrating P&T committee decisions into daily pharmacy practice. The implementation of this DUR program has enabled the P&T committee to conduct ongoing, systematic, criteria-based drug-use evaluations.

Botryomycosis caused by Serratia marcescens

We have reported a case of lymph node botryomycosis caused by Serratia marcescens, which has not been listed previously as an etiologic agent.

Infection due to organisms of the Mycobacterium fortuitum complex after augmentation mammaplasty: clinical and epidemiologic features

Periprosthetic infections due to Mycobacterium fortuitum and Mycobacterium chelonei occurred in 17 women over a 3.5-year period after implantation of prostheses for breast augmentation. The median incubation period for 16 of the women was 28 days (range, one week to over two years) after surgery; etiologic diagnosis was usually delayed for weeks to months. Odorless and serosanguineous or purulent material was found when the implants were removed, and acid-fast bacilli were often present when smears were examined. Wound infections were chronic and refractory to therapy with various antimicrobial agents. Persistent or recurrent mycobacterial infections complicated attempts to implant new prostheses. Whereas M. fortuitum isolates were susceptible to amikacin, multiple strains of M. fortuitum were distinguished by conventional antituberculous and broth microdilution susceptibility tests. Several clusters of infections were temporally and geographically related; however, sporadic cases were also reported, and no evidence of a contaminated common product or other single source of infection was found.

Relation of infection with Neisseria gonorrhoeae to ABO blood groups

The relation of infection with Neisseria gonorrhoeae to the blood groups A, B, AB, and O was examined in 584 women attending a prenatal clinic. The occurrence of gonorrhea was significantly higher in black patients with blood group B than in those with blood groups A, AB, or O.