Choroid plexus carcinoma in children: the Head Start experience

BACKGROUND

Choroid plexus carcinoma (CPC) is a rare aggressive intracranial neoplasm with a predilection for young children and a historically poor outcome. Currently, no defined optimal therapeutic strategy exists. The Head Start (HS) regimens have included irradiation-avoiding strategies in young children with malignant brain tumors using high dose chemotherapy to improve survival and minimize neurocognitive sequelae.

PROCEDURE

Three sequential HS studies have been conducted from 1991 to 2009. HS treatment strategy has consisted of maximal surgical resection followed by five cycles of intensive induction followed by consolidation myeloablative chemotherapy with autologous hematopoietic stem cell rescue (AuHCR). Irradiation was given following recovery from consolidation based on the patient's age and evidence of residual disease.

RESULTS

Twelve children with CPC (median age of 19.5 months) have been treated with HS regimens. Ten patients had >95% resection. Three patients had disseminated disease at diagnosis. Ten patients completed consolidation of whom five are alive, irradiation and disease free at 29, 43, 61, 66 and 89 months from diagnosis. Seven patients experienced tumor recurrence/progression at a median time of 13 months (range 2-43 months). Five patients received irradiation, one for residual disease and four upon progression or recurrence, of whom one is alive at 61 months. The 3- and 5-year progression-free survivals are 58% and 38% and overall survivals 83% and 62% respectively. Late deaths from disease beyond 5 years were also noted.

CONCLUSION

Head Start strategies may produce long-term remission in young children with newly diagnosed CPC with avoidance of cranial irradiation.

Lysine residues in the N-terminal huntingtin amphipathic α-helix play a key role in peptide aggregation

Huntington's disease is a genetic neurodegenerative disorder caused by an expansion in a polyglutamine domain near the N-terminus of the huntingtin (htt) protein that results in the formation of protein aggregates. Here, htt aggregate structure has been examined using hydrogen-deuterium exchange techniques coupled with tandem mass spectrometry. The focus of the study is on the 17-residue N-terminal flanking region of the peptide that has been shown to alter htt aggregation kinetics and morphology. A top-down sequencing strategy employing electron transfer dissociation is utilized to determine the location of accessible and protected hydrogens. In these experiments, peptides aggregate in a deuterium-rich solvent at neutral pH and are subsequently subjected to deuterium-hydrogen back-exchange followed by rapid quenching, disaggregation, and tandem mass spectrometry analysis. Electrospray ionization of the peptide solution produces the [M + 5H](5+) to [M + 10H](10+) charge states and reveals the presence of multiple peptide sequences differing by single glutamine residues. The [M + 7H](7+) to [M + 9](9+) charge states corresponding to the full peptide are used in the electron transfer dissociation analyses. Evidence for protected residues is observed in the 17-residue N-terminal tract and specifically points to lysine residues as potentially playing a significant role in htt aggregation.

Clinical outcomes after neurogenic stress induced cardiomyopathy in aneurysmal sub-arachnoid hemorrhage: a prospective cohort study

INTRODUCTION

Neurogenic stress cardiomyopathy (NCM) has been associated with poor outcomes in the setting of aneurysmal subarachnoid hemorrhage (aSAH). Much less is known regarding recovery of cardiac function. The aim of this prospective cohort study was to study the rate of early cardiac recovery after NCM and the potential effect of NCM on short term functional recovery. A secondary aim sought to determine whether certain biomarkers may be associated with the development of NCM.

METHODS

Patients with confirmed aSAH between November 2012 and October 2013 were prospectively enrolled and received echocardiograms within 48 h of admission. Ejection fraction (%) and regional wall motion abnormality score index (RWMI) were noted. All patients with confirmed aSAH had a troponin and BNP level drawn on admission. Patients with confirmed NCM received a follow up echocardiogram 7-21 days after the initial echocardiogram. Clinical follow up at 3 months evaluated mortality, mRS and mBI scores.

RESULTS

63 patients with confirmed aSAH were enrolled. In this cohort 11 (17%) patients were confirmed to have NCM. The NCM group had higher in-hospital mortality [n = 4(36.4%)] compared to the non-NCM group [n = 5(9.6%)] (p = .021). At 3 months the development of NCM was associated with an unfavorable mRS (p = 0.042) and mBI (p = 0.005). Both an elevated BNP (> 100 pg/mL) and elevated troponin (>0.3 mg/dL) were associated with the development of NCM. Follow-up echocardiograms were performed within 21 days of admission on 8 patients with NCM. An abnormal RWMI of 1.5 or higher was present in 5(71%) patients.

CONCLUSION

NCM is a frequent complication associated with aSAH. The onset of the disease occurs early in the course of aSAH and an elevated BNP and troponin may be associated with the onset of NCM. Cardiac function often remains impaired during the acute recovery phase potentially impeding resuscitation during this period. The routine use of short term follow-up echocardiography may be recommended.

Influence of fuel molecular structure on the volatility and oxidative potential of biodiesel particulate matter

We have studied the effect of chemical composition of biodiesel fuel on the physical (volatility) and chemical (reactive oxygenated species concentration) properties of nano particles emitted from a modern common-rail diesel engine. Particle emissions from the combustion of four biodiesels with controlled chemical compositions and different varying unsaturation degrees and carbon-chain lengths, together with a commercial diesel, were tested and compared in terms of volatility of particles and the amount of reactive oxygenated species carried by particles. Different blends of biodiesel and petro diesel were tested at several engine loads and speeds. We have observed that more saturated fuels with shorter carbon chain lengths result in lower particle mass but produce particles that are more volatile and also have higher levels of Reactive Oxygen Species. This highlights the importance of taking into account metrics that are relevant from the health effects point of view when assessing emissions from new fuel types.

Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

A particle based model to simulate microscale morphological changes of plant tissues during drying

Fundamental understanding on microscopic physical changes of plant materials is vital to optimize product quality and processing techniques, particularly in food engineering. Although grid-based numerical modelling can assist in this regard, it becomes quite challenging to overcome the inherited complexities of these biological materials especially when such materials undergo critical processing conditions such as drying, where the cellular structure undergoes extreme deformations. In this context, a meshfree particle based model was developed which is fundamentally capable of handling extreme deformations of plant tissues during drying. The model is built by coupling a particle based meshfree technique: Smoothed Particle Hydrodynamics (SPH) and a Discrete Element Method (DEM). Plant cells were initiated as hexagons and aggregated to form a tissue which also accounts for the characteristics of the middle lamella. In each cell, SPH was used to model cell protoplasm and DEM was used to model the cell wall. Drying was incorporated by varying the moisture content, the turgor pressure, and cell wall contraction effects. Compared to the state of the art grid-based microscale plant tissue drying models, the proposed model can be used to simulate tissues under excessive moisture content reductions incorporating cell wall wrinkling. Also, compared to the state of the art SPH-DEM tissue models, the proposed model better replicates real tissues and the cell-cell interactions used ensure efficient computations. Model predictions showed good agreement both qualitatively and quantitatively with experimental findings on dried plant tissues. The proposed modelling approach is fundamentally flexible to study different cellular structures for their microscale morphological changes at dehydration.

Lipidomic analyses of female mice lacking hepatic lipase and endothelial lipase indicate selective modulation of plasma lipid species

Hepatic lipase (HL) and endothelial lipase (EL) share overlapping and complementary roles in lipoprotein metabolism. The deletion of HL and EL alleles in mice raises plasma total cholesterol and phospholipid concentrations. However, the influence of HL and EL in vivo on individual molecular species from each class of lipid is not known. We hypothesized that the loss of HL, EL, or both in vivo may affect select molecular species from each class of lipids. To test this hypothesis, we performed lipidomic analyses on plasma and livers from fasted female wild-type, HL-knockout, EL-knockout, and HL/EL-double knockout mice. Overall, the loss of HL, EL, or both resulted in minimal changes to hepatic lipids; however, select species of CE were surprisingly reduced in the livers of mice only lacking EL. The loss of HL, EL, or both reduced the plasma concentrations for select molecular species of triacylglycerol, diacylglycerol, and free fatty acid. On the other hand, the loss of HL, EL, or both raised the plasma concentrations for select molecular species of phosphatidylcholine, cholesteryl ester, diacylglycerol, sphingomyelin, ceramide, plasmanylcholine, and plasmenylcholine. The increased plasma concentration of select ether phospholipids was evident in the absence of EL, thus suggesting that EL might exhibit a phospholipase A2 activity. Using recombinant EL, we showed that it could hydrolyse the artificial phospholipase A2 substrate 4-nitro-3-(octanoyloxy)benzoic acid. In summary, our study shows for the first time the influence of HL and EL on individual molecular species of several classes of lipids in vivo using lipidomic methods.

Characterizing changes in snow crab (Chionoecetes opilio) cryptocyanin protein during molting using matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry

RATIONALE

We report the matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) characterization of the cryptocyanin proteins of the juvenile Chionoecetes opilio crabs during their molting and non-molting phases. In order to assess the structural cryptocyanin protein differences between the molting and non-molting phases, the obtained peptides were sequenced by MALDI low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS).

METHODS

The cryptocyanin protein was isolated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by MALDI-TOF/TOF-MS. The purified cryptocyanin protein was sequenced, using the 'bottom-up' approach. After tryptic digestion, the peptide mixture was analyzed by MALDI-QqTOF-MS/MS and the data obtained were used for the peptide mass fingerprinting (PMF) identification by means of the Mascot database.

RESULTS

It was demonstrated using MALDI-TOF/TOF-MS that the actual molecular weights of the non-molting and molting cryptocyanin proteins were different; these were, respectively, 67.6 kDa and 68.1 kDa. Using low-energy CID-MS/MS we have sequenced the trytic peptides to monitor the differences and similarities between the cryptocyanin molecular structures during the molting and non-molting stages.

CONCLUSIONS

We have demonstrated for the first time that the actual molecular masses of the cryptocyanin protein during the molting and non-molting phases were different. The MALDI-CID-MS/MS analyses allowed the sequencing of the cryptocyanins after tryptic digestion, during the molting and non-molting stages, and showed some similarities and staggering differences between the identified cryptocyanin peptides.

Infectious complications in the first year following autologous hematopoietic progenitor cell rescue for children with brain tumors

BACKGROUND

High-dose chemotherapy with autologous hematopoietic progenitor cell rescue (AuHPCR) for pediatric patients with brain tumors has become an important therapeutic modality to avoid or delay the long-term effects of cranial irradiation. Data on post-AuHPCR infectious complications in this population are lacking. This single institution retrospective review reports the prophylactic practices and infections in the first year following AuHPCR in pediatric patients with brain tumors.

PROCEDURE

The medical record of patients who underwent AuHPCR for the treatment of a malignant brain tumor at Children's Hospital Los Angeles between 1988 and 2010 were reviewed. Patients without prior irradiation who were free of disease at 1 year without additional chemotherapy were evaluated for all infectious disease complications occurring from time of neutrophil engraftment to 1 year post-AuHPCR.

RESULTS

Forty-three of the 115 eligible patients were included. The median time to neutrophil engraftment was 11 days (range: 8-43 days), and 20 Grade III/IV (no Grade V) infectious episodes developed in 15 patients (35%). Fourteen episodes of bacteremia (70%) were catheter-related, predominantly gram-negative (71%), and polymicrobial (50%). There were no fungal or pneumocystis infections and only 1 of 25 (4%) at-risk patients developed VZV reactivation.

CONCLUSIONS

These data suggest patients with brain tumors undergoing AuHPCR have few late-occurring non-catheter-related post-transplant infections indicating that prophylaxis practices were sufficient. Central lines should be removed soon after engraftment, but those with central line infections should receive adequate treatment including gram-negative coverage. In addition, only at-risk patients who receive further irradiation may benefit from VZV reaction prophylaxis.

The relationship between delayed infarcts and angiographic vasospasm after aneurysmal subarachnoid hemorrhage

BACKGROUND

Delayed cerebral ischemia is common after aneurysmal subarachnoid hemorrhage (aSAH) and is a major contributor to poor outcome. Yet, although generally attributed to arterial vasospasm, neurological deterioration may also occur in the absence of vasospasm.

OBJECTIVE

To determine the relationship between delayed infarction and angiographic vasospasm and compare the characteristics of infarcts related to vasospasm vs those unrelated.

METHODS

A retrospective review of patients with aSAH admitted from July 2007 through June 2011. Patients were included if they were admitted within 48 hours of SAH, had a computed tomography scan both 24 to 48 hours following aneurysm treatment and ≥7 days after SAH, and had a catheter angiogram to evaluate for vasospasm. Delayed infarcts seen on late computed tomography but not postprocedurally were attributed to vasospasm if there was moderate or severe vasospasm in the corresponding vascular territory on angiography. Infarct volume was measured by perimeter tracing.

RESULTS

Of 276 aSAH survivors, 134 had all imaging requisite for inclusion. Fifty-four (34%) had moderate or severe vasospasm, of whom 17 (31%) had delayed infarcts, compared with only 3 (4%) of 80 patients without vasospasm (P < .001). There were a total of 29 delayed infarcts in these 20 patients; 21 were in a territory with angiographic vasospasm, but 8 (28%) were not. Infarct volume did not differ between vasospasm-related (18 ± 25 mL) and vasospasm-unrelated (11 ± 12 mL) infarcts (P = .54), but infarcts in the absence of vasospasm were more likely watershed (50% vs. 10%, P = .03).

CONCLUSION

Delayed infarcts following aSAH can occur in territories without angiographic vasospasm and are more likely watershed in distribution.

Olfactory ensheathing cells, but not Schwann cells, proliferate and migrate extensively within moderately X-irradiated juvenile rat brain

Olfactory ensheathing cells (OECs) and Schwann cells (SCs) share many characteristics, including the ability to promote neuronal repair when transplanted directly into spinal cord lesions, but poor survival and migration when transplanted into intact adult spinal cord. Interestingly, transplanted OECs, but not SCs, migrate extensively within the X-irradiated (40 Gy) adult rat spinal cord, suggesting distinct responses to environmental cues [Lankford et al., (2008) GLIA 56:1664-1678]. In this study, GFP-expressing OECs and SCs were transplanted into juvenile rat brains (hippocampus) subjected to a moderate radiation dose (16 Gy). As in the adult spinal cord, OECs, but not SCs, migrated extensively within the irradiated juvenile rat brain. Unbiased stereology revealed that the number of OECs observed within irradiated rat brains three weeks after transplantation was as much as 20 times greater than the number of cells transplanted, and the cells distributed extensively within the brain. In conjunction with the OEC dispersion, the number of activated microglia in OEC-transplanted irradiated brains was reduced. Unlike in the intact adult spinal cord, both OECs and SCs showed some, but limited, migration within nonirradiated rat brains, suggesting that the developing brain may be a more permissive environment for cell migration than the adult CNS. These results show that OECs display unique migratory, proliferative, and microglia interaction properties as compared with SCs when transplanted into the moderately X-irradiated brain.

Chloridobis[2-(diphenylphosphanyl)ethanamine-κ(2)P,N](triphenylphosphane-κP)ruthenium(II) chloride toluene monosolvate

The aminophosphane ligand 1-amino-2-(diphenylphosphanyl)ethane [Ph2P(CH2)2NH2] reacts with dichloridotris(triphenylphosphane)ruthenium(II), [RuCl2(PPh3)3], to form chloridobis[2-(diphenylphosphanyl)ethanamine-κ(2)P,N](triphenylphosphane-κP)ruthenium(II) chloride toluene monosolvate, [RuCl(C18H15P)(C14H16NP)2]Cl·C7H8 or [RuCl(PPh3){Ph2P(CH2)2NH2}2]Cl·C7H8. The asymmetric unit of the monoclinic unit cell contains two molecules of the Ru(II) cation, two chloride anions and two toluene molecules. The Ru(II) cation is octahedrally coordinated by two chelating Ph2P(CH2)2NH2 ligands, a triphenylphosphane (PPh3) ligand and a chloride ligand. The three P atoms are meridionally coordinated, with the Ph2P- groups from the ligands being trans. The two -NH2 groups are cis, as are the chloride and PPh3 ligands. This chiral stereochemistry of the [RuCl(PPh3){Ph2P(CH2)2NH2}2](+) cation is unique in ruthenium-aminophosphane chemistry.

Treatment of children with diffuse intrinsic pontine gliomas with chemoradiotherapy followed by a combination of temozolomide, irinotecan, and bevacizumab

BACKGROUND

Diffuse intrinsic pontine gliomas (DIPG) are inoperable and highly resistant tumors to chemotherapy and irradiation. DIPG has the worst prognosis among all pediatric brain tumors and the overwhelming majority of patients die within 6-18 months after diagnosis.

METHODS

We retrospectively reviewed the charts of six DIPG patients treated with chemoradiotherapy (daily carboplatin and oral etoposide in five patients and temozolomide in one patient) followed by maintenance chemotherapy consisting of irinotecan, temozolomide, and bevacizumab at our institution between January 2007 until December 2007.

RESULTS

Event-free survival (EFS) and overall survival (OS) were 10.4 ± 3.08 and 14.6 ± 3.55 months, respectively. Side effects in the patients included hypertension in two, abdominal cramping and diarrhea in four, and neutropenia in five patients.

CONCLUSIONS

This augmented regimen was associated with increased but tolerable toxicity and a modest increase in EFS and OS when compared with published literature in patients with DIPG (median EFS and OS of 6.1 and 9.6 months, respectively). More effective therapies are desperately needed.

Feasibility of dasatinib in children and adolescents with new or recurrent central nervous system germinoma

Germinomas and embryonal carcinomas are central nervous system (CNS) germ cell tumors (GCT) that may overexpress the proto-oncogene c-KIT, a receptor tyrosine kinase, of which dasatinib is a potent inhibitor. This retrospective review presents the feasibility and tolerability of dasatinib administration in select patients with CNS germinoma. Between November 2008 and April 2010, six patients with newly diagnosed (n = 3) or recurrent (n = 3) CNS GCT were treated in an effort to avoid irradiation and/or delay recurrence. The daily doses administered were 100-170 mg/m(2) with mostly grade 1-2 toxicities. Dasatinib may play a role in future treatment strategies for CNS GCT.

Novel Use of AngioVac System to Prevent Pulmonary Embolism during Radical Nephrectomy with Inferior Vena Cava Thrombectomy

Venous tumor thrombus occurs in 5-10% of patients with renal cell carcinoma. Surgical excision offers the best chance for survival, but is technically difficult. Risk of pulmonary embolism from venous thrombus or tumor thrombus is high, especially with tumors located higher in the inferior vena cava. Cardiopulmonary bypass may be used when a tumor extends above the diaphragm, but carries significant risk. We present an 86-year-old woman with a 7 cm renal mass extending into the inferior vena cava just below the confluence of the hepatic vessels. Prior to surgery she was found to have increasing pulmonary embolisms despite appropriate anticoagulation. Intraoperatively, the AngioVac aspiration system was utilized to prevent further pulmonary embolism. This is the first reported case of the use of this system during radical nephrectomy.

Short-term outcome of psychogenic non-epileptic seizures after communication of the diagnosis

We previously described a communication strategy for the delivery of the diagnosis of psychogenic non-epileptic seizures (PNES) that was acceptable and effective at communicating the psychological cause of PNES. This prospective multicenter study describes the short-term seizure and psychosocial outcomes after the communication of the diagnosis and with no additional treatment. Participants completed self-report measures at baseline, two and six months after the diagnosis (seizure frequency, HRQoL, health care utilization, activity levels, symptom attributions and levels of functioning). Thirty-six participants completed the self-report questionnaires. A further eight provided seizure frequency data. After six months, the median seizure frequency had dropped from 10 to 7.5 per month (p=0.9), 7/44 participants (16%) were seizure-free, and an additional 10/44 (23%) showed greater than 50% improvement in seizure frequency. Baseline questionnaire measures demonstrated high levels of impairment, which had not improved at follow-up. The lack of change in self-report measures illustrates the need for further interventions in this patient group.

Cholesterol efflux analyses using stable isotopes and mass spectrometry

Cholesterol efflux from macrophages and the vascular wall is the initial step of the cardiovascular protective reverse cholesterol transport process. This study demonstrates a mass spectrometry based assay to measure the cellular and medium content of [d(7)]cholesterol and unlabeled cholesterol that can be used to measure cholesterol efflux from cell lines. Using a triple-quadrupole electrospray ionization-MS instrument in direct infusion mode, product ion scanning for m/z 83, neutral loss (NL) 375.5 scanning, and NL 368.5 scanning were used to detect cholesterol (as an acetylated derivative), [d(7)]cholesteryl ester (CE), and unlabeled CE, respectively. The same mass of [d(7)]cholesterol was substituted for [(3)H]cholesterol under standard efflux assay conditions. At the end of [d(7)]cholesterol loading, the intracellular mass of [d(7)]cholesterol was twofold greater than that of unlabeled cholesterol, and the intracellular [d(7)]CE profile was similar to that of unlabeled CE. Efflux of cholesterol to apolipoprotein A-I and high-density lipoproteins was similar comparing efflux of either [d(7)]cholesterol or [(3)H]cholesterol as measured by following efflux of the tracers only. This technique also can be used to assess the efflux of unlabeled cholesterol to acceptors in medium that are initially cholesterol-free (e.g., apolipoprotein A-I). Taken together, this mass spectrometry-based assay provides new molecular detail to assess cholesterol efflux.

Consequences of stopping and restarting leptin in an adolescent with lipodystrophy

BACKGROUND/AIMS

Lipodystrophy encompasses a group of rare disorders characterized by deficiency of adipose tissue resulting in hypoleptinemia, and metabolic abnormalities including insulin resistance, diabetes, dyslipidemia, and nonalcoholic steatohepatitis. Leptin replacement effectively ameliorates these metabolic derangements. We report effects of leptin discontinuation and resumption in a child with acquired generalized lipodystrophy.

METHODS

Intermittent treatment with leptin with follow-up over 5 years.

RESULTS

Pretreatment metabolic abnormalities included insulin resistance, hypertriglyceridemia and steatohepatitis. Leptin was started at the age of 10 years. After 2 years, the family requested discontinuation of leptin due to lack of visible physical changes. Nine months later, worsened metabolic abnormalities and arrest of pubertal development were observed. Leptin was restarted, followed by improvements in metabolic parameters. Laboratory changes (before vs. 6 months after restarting leptin) were: fasting glucose from 232 to 85 mg/dl, insulin from 232 to 38.9 µU/ml, HbA(1c) from 7.5 to 4.8%, triglycerides from 622 to 96 mg/dl, ALT from 229 to 61 U/l, AST from 91 to 18 U/l, and urine protein:creatinine ratio from 5.4 to 0.3. Progression of puberty was observed 1 year after restarting leptin.

CONCLUSION

Initial leptin therapy likely prevented progression of metabolic abnormalities. Treatment discontinuation led to rapid metabolic decomposition and pubertal arrest. Reintroduction of leptin reversed metabolic abnormalities and allowed normal pubertal progression.

Liposarcoma of the spermatic cord: a report of two cases

Liposarcomas of the spermatic cord are unusual and rarely reported in the literature. These tumours can sometimes be mistaken for the common scrotal swellings such as hydrocoeles and hernias. Careful clinical and radiological examination will help in appropriate preoperative planning and surgery by an experienced surgical team. We report our experience of two cases of such scrotal swellings.

The origin of pelletal lapilli in explosive kimberlite eruptions

Kimberlites are volatile-rich magmas from mantle depths of ≥ 150  km and are the primary source of diamonds. Kimberlite volcanism involves the formation of diverging pipes or diatremes, which are the locus of high-intensity explosive eruptions. A conspicuous and previously enigmatic feature of diatreme fills are 'pelletal lapilli'--well-rounded clasts consisting of an inner 'seed' particle with a complex rim, thought to represent quenched juvenile melt. Here we show that these coincide with a transition from magmatic to pyroclastic behaviour, thus offering fundamental insights into eruption dynamics and constraints on vent conditions. We propose that pelletal lapilli are formed when fluid melts intrude into earlier volcaniclastic infill close to the diatreme root zone. Intensive degassing produces a gas jet in which locally scavenged particles are simultaneously fluidised and coated by a spray of low-viscosity melt. A similar origin may apply to pelletal lapilli in other alkaline volcanic rocks, including carbonatites, kamafugites and melilitites.