N-glycosylation of α1D-adrenergic receptor N-terminal domain is required for correct trafficking, function, and biogenesis

G protein-coupled receptor (GPCR) biogenesis, trafficking, and function are regulated by post-translational modifications, including N-glycosylation of asparagine residues. α1D-adrenergic receptors (α1D-ARs) - key regulators of central and autonomic nervous system function - contain two putative N-glycosylation sites within the large N-terminal domain at N65 and N82. However, determining the glycosylation state of this receptor has proven challenging. Towards understanding the role of these putative glycosylation sites, site-directed mutagenesis and lectin affinity purification identified N65 and N82 as bona fide acceptors for N-glycans. Surprisingly, we also report that simultaneously mutating N65 and N82 causes early termination of α1D-AR between transmembrane domain 2 and 3. Label-free dynamic mass redistribution and cell surface trafficking assays revealed that single and double glycosylation deficient mutants display limited function with impaired plasma membrane expression. Confocal microscopy imaging analysis and SNAP-tag sucrose density fractionation assays revealed the dual glycosylation mutant α1D-AR is widely distributed throughout the cytosol and nucleus. Based on these novel findings, we propose α1D-AR transmembrane domain 2 acts as an ER localization signal during active protein biogenesis, and that α1D-AR N-terminal glycosylation is required for complete translation of nascent, functional receptor.

Transcranial focused ultrasound, pulsed at 40 Hz, activates microglia acutely and reduces Aβ load chronically, as demonstrated in vivo

OBJECTIVE

Iaccarino et al. (2016) [1] exposed 1 h of light flickering at 40 Hz to awake 5XFAD Alzheimer's Disease (AD) mouse models, generating action potentials at 40 Hz, activating ∼54% of microglia to colocalize with Aβ plaque, acutely, and clearing ∼ 50% of Aβ plaque after seven days, but only in the visual cortex.

HYPOTHESIS

Transcranially delivered, focused ultrasound (tFUS) can replicate the results of Iaccarino et al. (2016) [1] but throughout its area of application.

METHODS

We exposed sedated 5XFAD mice to tFUS (2.0 MHz carrier frequency, 40 Hz pulse repetition frequency, 400 μs-long pulses, spatial peak pulse average value of 190 W/cm²). Acute studies targeted tFUS into one hemisphere of brain centered on its hippocampus for 1 h. Chronic studies targeted comparable brain in each hemisphere for 1 h/day for five days.

RESULTS

Acute application of tFUS activated more microglia that colocalized with Aβ plaque relative to sham ultrasound (36.0 ± 4.6% versus 14.2 ± 2.6% [mean ± standard error], z = 2.45, p < 0.014) and relative to the contralateral hemisphere of treated brain (36.0 ± 4.6% versus 14.3 ± 4.0%, z = 2.61, p < 0.009). Chronic application over five days reduced their Aβ plaque burden by nearly half relative to paired sham animals (47.4 ± 5.8%, z = - 2.79, p < 0.005).

CONCLUSION

Our results compare to those of Iaccarino et al. (2016) [1] but throughout the area of ultrasound-exposed brain. Our results also compare to those achieved by medications that target Aβ, but over a substantially shorter period of time. The proximity of our ultrasound protocol to those shown safe for non-human primates and humans may motivate its rapid translation to human studies.

A sea change in our view of overturning in the subpolar North Atlantic

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Cost of multiple sclerosis by level of disability: a review of literature

We performed a review of the economic literature to identify what is known about the relationship between Expanded Disability Status Scale (EDSS) categories and cost of multiple sclerosis (MS). We sought cohort studies of patients with multiple sclerosis that described the costs attributed to each EDSS score and utilized specific inclusion criteria for the selection of 10 studies. We found that both direct and indirect costs rise continuously with increasing EDSS category, and this rise is qualitatively exponential. The rise in indirect costs appears at lower EDSS scores. The cost of a relapse occurring in any given EDSS category exceeds that associated with that particular EDSS category. Few studies comprehensively assessed the entire spectrum of the costs, and much of the literature is based on EDSS categories in coarse groupings. In spite of several variations between studies, one important conclusion that we can draw is that rise in cost is positively correlated to scores on the EDSS categories, and therefore agents with a capacity to prevent or arrest the rate of MS progression may affect the overall cost of MS.

Nasal Foreign Bodies: A Sweet Experiment

INTRODUCTION

It is generally accepted that paediatric intranasal foreign bodies should be removed in the emergency setting. In the case of a difficult to access dissolvable foreign body in an uncooperative child, the question must be raised regarding whether or not a watch and wait strategy is more appropriate. We ask: How long does it take for popular sweets (candy) to dissolve in the human nose?

METHODS

Five popular UK sweets were placed in the right nasal cavity of a 29-year-old male (the author) with no sino-nasal disease. Time taken to dissolve was recorded.

RESULTS

All five sweets were completely dissolved in under one hour.

DISCUSSION

A watch and wait strategy in favour of examination under anaesthetic may be a viable option in some cases. Limitations of the study include the age of the participant and size of the sweets. It is also important in practice that the clinician is able to elicit an accurate history regarding the exact nature of the foreign body.

CONCLUSION

It remains prudent to perform an examination under anaesthetic of an uncooperative child with a solid or unknown nasal foreign body. However, if the clinician can be certain the foreign body is a small sugar or chocolate based sweet only, a watch and wait strategy may be a reasonable choice.

Determination of the photolysis rate coefficient of monochlorodimethyl sulfide (MClDMS) in the atmosphere and its implications for the enhancement of SO2 production from the DMS + Cl2 reaction

In this work, the photolysis rate coefficient of CH3SCH2Cl (MClDMS) in the lower atmosphere has been determined and has been used in a marine boundary layer (MBL) box model to determine the enhancement of SO2 production arising from the reaction DMS + Cl2. Absorption cross sections measured in the 28000-34000 cm(-1) region have been used to determine photolysis rate coefficients of MClDMS in the troposphere at 10 solar zenith angles (SZAs). These have been used to determine the lifetimes of MClDMS in the troposphere. At 0° SZA, a photolysis lifetime of 3-4 h has been obtained. The results show that the photolysis lifetime of MClDMS is significantly smaller than the lifetimes with respect to reaction with OH (≈ 4.6 days) and with Cl atoms (≈ 1.2 days). It has also been shown, using experimentally derived dissociation energies with supporting quantum-chemical calculations, that the dominant photodissocation route of MClDMS is dissociation of the C-S bond to give CH3S and CH2Cl. MBL box modeling calculations show that buildup of MClDMS at night from the Cl2 + DMS reaction leads to enhanced SO2 production during the day. The extra SO2 arises from photolysis of MClDMS to give CH3S and CH2Cl, followed by subsequent oxidation of CH3S.

Abnormal cerebral microstructure in premature neonates with congenital heart disease

BACKGROUND AND PURPOSE

Abnormal cerebral microstructure has been documented in term neonates with congenital heart disease, portending risk for injury and poor neurodevelopmental outcome. Our hypothesis was that preterm neonates with congenital heart disease would demonstrate diffuse cerebral microstructural abnormalities when compared with critically ill neonates without congenital heart disease. A secondary aim was to identify any association between microstructural abnormalities, white matter injury (eg, punctate white matter lesions), and other clinical variables, including heart lesions.

MATERIALS AND METHODS

With the use of tract-based spatial statistics, an unbiased, voxelwise method for analyzing diffusion tensor imaging data, we compared 21 preterm neonates with congenital heart disease with 2 cohorts of neonates without congenital heart disease: 28 term and 27 preterm neonates, identified from the same neonatal intensive care unit.

RESULTS

Compared with term neonates without congenital heart disease, preterm neonates with congenital heart disease had microstructural abnormalities in widespread regions of the central white matter. However, 42% of the preterm neonates with congenital heart disease had punctate white matter lesions. When neonates with punctate white matter lesions were excluded, microstructural abnormalities remained only in the splenium. Preterm neonates with congenital heart disease had similar microstructure to preterm neonates without congenital heart disease.

CONCLUSIONS

Diffuse microstructural abnormalities were observed in preterm neonates with congenital heart disease, strongly associated with punctate white matter lesions. Independently, regional vulnerability of the splenium, a structure associated with visual spatial function, was observed in all preterm neonates with congenital heart disease.

Severe retinal injuries from paintball projectiles

BACKGROUND

To determine the outcomes and circumstances of retinal injuries caused by blunt trauma from paintball pellet projectiles.

METHODS

Retrospective case series of all patients who presented with retinal injuries due to paintball-related trauma to 2 retina specialists in a clinical setting from 2004 to 2005. Patients were followed for a mean of 7.3 months, and retinal trauma was documented with retinal photographs and ocular coherence tomography as needed. Best corrected visual acuity (BCVA) was the main outcome measure.

RESULTS

Three eyes of 3 patients suffered severe retinal injuries after blunt trauma from a paintball pellet. Together, the 3 eyes demonstrated extensive retinal findings, including commotio retinae, choroidal rupture, and macular hole. BCVA at last follow-up ranged from 20/80 to hand motions.

INTERPRETATION

Our small case series indicates that retinal trauma from paintball injuries is not uncommon and results in severe long-term visual morbidity. The sale of paintball guns and pellets should be strictly prohibited for minors, and adults should be educated about the need for appropriate ocular protection and the potentially serious consequences of the use of these guns outside of commercial settings.

Safety Profile of Intravitreal Triamcinolone Acetonide

BACKGROUND

There is currently a widespread use of intravitreal triamcinolone acetonide (IVTA) for age-related macular degeneration, diabetic macular edema, cystoid macular edema secondary to retinal vein occlusions, and uveitis. The aim of this investigation was to assess the rates of various complications associated with this treatment and to determine which factors are associated with the development of these complications.

METHODS

A retrospective interventional case series of all patients from one retina specialist undergoing IVTA was conducted in a clinical setting from 2002 to 2005. All disease entities were included. Patients were followed for a mean of 9.5 months after receiving 4 mg (0.1 mL) of nonfiltered triamcinolone acetonide (TA). All complications associated with the injection procedure or with the TA were noted.

RESULTS

Two hundred and twenty-three (223) eyes of 192 patients received a total of 336 IVTA injections between 2002 and 2005. The mean age was 73.3 years and mean follow-up was 9.5 months. A single injection was performed in 144 eyes (64.6%); 2 IVTAs in 55 eyes (24.7%); 3 IVTAs in 16 eyes (7.2%), and 3.6% of eyes had more than 3 injections at a minimal interval of 3 months. The only immediate complication was a single injection (0.3%) associated with a temporary occlusion of the central retinal artery, which opened immediately following anterior paracentesis. Late complications included endophthalmitis in 1 of 336 (0.3%) injections and a steroid response requiring glaucoma medication in 60 of 192 patients (31.3%). In patients with preexisting glaucoma, 58.8% required additional glaucoma medication. Glaucoma-filtering surgery was required in 2 of 192 patients (1.0%).

CONCLUSIONS

In the study center, the IVTA is extremely safe in patients without a history of glaucoma. However, patients with preexisting glaucoma with progressive optic neuropathy must be treated with great caution.

A lay person versus a trained endoscopist: can the preop endoscopy simulator detect a difference?

The purpose of this study was to establish construct validation of a flexible sigmoidoscopy simulator by comparing training-level grouped subjects. These included clerical staff (n = 10), residents (n = 19), and experts (n = 5). Each participant performed 3 scopes. The ANOVA group-based results for trainer-measured variables are shown in Table 1. These results demonstrate that the flexible sigmoidoscopy simulator distinguished the trained from the untrained and the resident from the expert. Although there was no statistically significant differences between the senior residents and the experts, the expert commonly outperformed the residents. Establishing the transferability of simulator training to real life is next. If the transfer of skill can be established, it may give rise to a new skills training approach.

Familial vocal fold paralysis

Familial clustering of congenital bilateral abductor vocal fold paralysis has been reported very rarely. So far, only a handful of cases have been reported, mostly with the autosomal dominant of X-linked recessive mode of inheritance. We describe the cases of a brother and sister, who presented with neonatal stridor due to bilateral abductor vocal fold paralysis. First-degree parental consanguinity suggests an autosomal recessive mode of inheritance. Karyotype analysis revealed a paracentric balanced inversion of chromosome 13 in both cases, that was also present in the unaffected mother. An updated review of the literature on this interesting but rare condition is also presented.

Large-volume, coolable spectroscopic cell for aerosol studies

We have constructed a coolable spectroscopic cell for characterizing the physical and chemical properties of simulated atmospheric aerosol particles. The cell is designed for experiments in which the refractive indices, freezing temperatures, and the phase and chemical composition of a wide range of aerosol types are measured. The relatively large volume (0.075 m(3)) of the cell reduces wall-aerosol interactions and allows the aerosol residence time to exceed 2 h. The cell has been optically interfaced to Fourier-transform spectrometers to record broadband infrared, visible, and ultraviolet extinction spectra of aerosol particles and gas-phase components over a range of temperatures (180-300 K). The data generated with the cell have applications in remote sensing, radiative transfer models, heterogeneous atmospheric chemistry, and pollution studies.

Body image and weight consciousness among South Asian, Italian and general population women in Britain

Italians in Britain have low rates of coronary heart disease while South Asians have high rates, which correspond to a tendency to central abdominal fat deposition and overweight. World variations in attitudes to body size are thought to be related to economic security. This cross-sectional study employed a range of measures including photographic silhouettes of known BMI to investigate the attitudes of 259 South Asian, Italian and general population women (aged 20-42 years) towards body size. Migrants are compared with British-born minority members. Our results indicate that although migrant South Asians were less happy with their weight than migrant Italians, fewer had tried to lose weight in the past or had experienced external pressures to change their bodies. More migrant South Asians than Italians or general population women equated one of the four largest shapes (BMI 28-38) with health and successful reproduction. All groups wanted to resemble one of the two thinnest shapes, equating them with longevity, likelihood of marriage and job success. British-born South Asians generally showed a considerable degree of convergence towards general population women's negative attitudes to large body size, but British-born Italians' attitudes were significantly more negative even than general population women. The study's conclusions were that South Asian health beliefs are an important focus of resistance to slimness. The tendency of migrant South Asians to equate large size with health contrasts with the opposing views of Italian and general population women. British-born South Asians' views are modifying from those of migrants, but significant differences remain when compared with general population women and British-born Italians. Present differences in economic security offer only a partial explanation; South Asian attitudes may be explained by economic insecurity in the past.

Final report of the FOPE II Pediatric Subspecialists of the Future Workgroup

The report of the Pediatric Subspecialists of the Future Workgroup of the Second Task Force on Pediatric Education reviews the critical changes of the past 2 decades that have affected the provision of pediatric subspecialty services, education of pediatric health care providers, and the acquisition and application of new knowledge. The report considers the future needs that will determine the ability of pediatric subspecialists to meet identified goals. Recommendations for change in the education, role, and financing of the pediatric subspecialist are reported together with those of other workgroups. Pediatrics 2000;106(suppl):1224-1244; pediatric subspecialist, pediatric subspecialist workforce, education pediatric subspecialist, research pediatric subspecialist.

Tracheomalacia and breath holding: a case report

A child with a long standing history of cyanotic breath holding attacks presented with acute respiratory distress. Subsequent investigation established that her clinical condition was caused by tracheomalacia. We hypothesise that tracheomalacia might be an under recognised contributor to cyanotic breath holding attacks, the pathogenesis of which is poorly understood.

The Patient Findings Questionnaire: one solution to an important standardized patient examination problem

PURPOSE

To describe the Patient Findings Questionnaire (PFQ) and compare its scores and pass/fail decisions with those obtained from standardized patient (SP) examination checklists.

METHOD

Checklists and PFQs were used to assess data acquisition by 790 second-year medical students. PFQs were composed of multiple-choice items designed to determine whether examines had acquired key historical patient information.

RESULTS

At the item level, the two measurement methods yielded the same decisions about data acquisition on 88% of observed occasions. Most discrepancies (74%) involved SPs rating examinees as having elicited information when the examinee was unable to answer the associated PFQ item. At the test level, the two instruments yielded the same pass/fail decision on a large majority of occasions.

CONCLUSIONS

The PFQ and checklist yielded similar data acquisition scores and decisions at the item and test levels. Replacement of the checklist with the PFQ should result in examinees' behaving in a way more consistent with recommended interviewing practices.

Training pediatricians for the evolving generalist-specialist interface in the managed care era

Managed care involves the linkage of service delivery and financing. One of the outgrowths of the rapid expansion of managed care over the past decade has been an increasing consensus that the generalist of the future will need to manage more of the patients traditionally cared for by subspecialists. Subspecialty education for pediatric residents becomes increasingly important as the role of the pediatric generalist enlarges to include independent outpatient management of some less complex but traditional subspecialty patients as well as collaborative management of more complex patients. To prepare for this role, a balanced exposure to subspecialty problems in outpatient as well as inpatient settings is required. At the same time, however, the growth of managed care has led to certain barriers for providing this enhanced training. This article describes the effects of managed care on the role and scope of the pediatric subspecialist as well as on educational strategies for coping with these changes while reshaping the roles of both generalists and subspecialists for maximal effectiveness in meeting the health care needs of children.

c-fos expression in isolated rat spinal cord

Expression of c-fos-immunoreactivity (c-fos-ir) has been demonstrated in the dorsal horn of lumbar segments of an isolated spinal cord preparation from 3 week old rats. The method of preparation generated a low level of c-fos-ir activity which was not significantly altered by low intensity (1.5 times threshold) dorsal root stimulation, but was significantly increased by high intensity (20 times threshold) stimulation. Replacement of the calcium in the bathing medium by 2 mM manganese suppressed all detectable c-fos-ir, whereas inclusion of 0.5 microM capsaicin caused intense c-fos-ir expression in the absence of stimulation. The number of dorsal horn cells exhibiting c-fos-ir increased between 0.5 and 1 h after stimulation, reaching a maximum at 2 h, with no further increase at longer intervals. Few positive cells were found when the incubation temperature was reduced from 27 to 20 degrees C. The strongest increase in c-fos-ir was found in the dorsal horn ipsilateral to the stimulated dorsal root and a smaller, but significant, increase was also seen in the contralateral dorsal horn. Cords obtained from animals treated at 1 day old with capsaicin to destroy afferent C fibres showed a reduction in the number of c-fos-ir positive cells induced by high intensity dorsal root stimulation. This preparation will aid detailed investigation of the pharmacology of nociceptive pathways.

In vitro response of Escherichia coli to antibiotics and ultrasound at various insonation intensities

Microbial infections on implanted medical devices are difficult to treat. Application of 70 kHz ultrasonic irradiation to gentamicin treatment greatly enhanced the action of the antibiotic in terms of reduced viable bacterial concentrations. Ultrasonic irradiation was carried out at various insonation intensities that were noninhibitory in the absence of antibiotic. Synergistic killing was observed to be a function of ultrasonic intensity. Greatest killing (approximately 5 log reduction in viable population) was realized at full intensity (4.5 W/cm2), and decreased with reductions in power density. At lowest intensity (10 mW/cm2), no significant acoustic enhanced killing was noted.

Gabapentin, ineffective in normal rats, markedly reduces C-fibre evoked responses after inflammation

Gabapentin (Neurontin) is a novel anticonvulsant with an as yet unknown mechanism of action. This electrophysiological study investigated the potential antinociceptive actions of systemically administered gabapentin in normal animals and after inflammation induced by the injection of carrageenan. Gabapentin facilitated the noxious evoked responses of dorsal horn neurones recorded in normal animals. In complete contrast, gabapentin strongly and dose-dependently inhibited the C-fibre evoked response and post-discharge, but not the A beta-fibre evoked response, of neurones recorded in animals 3 h after the injection of carrageenan. This unique and selective profile of gabapentin may provide a novel treatment for clinical inflammatory pain states.

Pathophysiology and treatment of cocaine toxicity: implications for the heart and cardiovascular system

OBJECTIVE

To review the data on pharmacology, pathophysiology and treatment of cocaine toxicity, with particular relevance to the heart and cardiovascular system.

DATA SOURCE AND STUDY SELECTION

Published epidemiology, laboratory and clinical studies on the pharmacology, electrophysiology and pathophysiology of cocaine toxicity and its treatment.

MAIN RESULTS

Cocaine toxicity-related morbidity and mortality are frequent due to the potent pharmacological effects of the drug as an indirect-acting sympathomimetic agent and its class I antiarrhythmic property paradoxically inducing pro-arrhythmia. The cardiac and cardiovascular toxic effects of cocaine include various degrees of myocardial ischemia, cardiac arrhythmias, cardiotoxicity, hypertensive effects, cerebrovascular effects and a hypercoagulable state. Treatment of cocaine toxicity must be based on the multiple factors leading to the toxicity. Sodium bicarbonate appears to have an important role in the acute setting with conduction abnormalities, seizures or acidosis. Unopposed alpha-stimulation provided by beta-blockade should be avoided. Central nervous system hyperexcitability should be treated with diazepam. The use of calcium antagonists appears logical.

CONCLUSION

Cocaine is an alkaloid with widespread illicit use. The rationale for treating acute cocaine intoxication has become clearer and more logical with increased knowledge of its mechanisms of action.

The antiepileptic agent gabapentin (Neurontin) possesses anxiolytic-like and antinociceptive actions that are reversed by D-serine

This report describes the activity of the antiepileptic agent gabapentin (Neurontin) in animal models predictive of anxiolysis and analgesia. Gabapentin displayed anxiolytic-like action in the rat conflict test, the mouse light/dark box and the rat elevated X-maze with respective minimum effective doses (MEDs) of 3, 10 and 30 mg/kg. Furthermore, gabapentin also induced behavioural changes suggestive of anxiolysis in the marmoset human threat test with a MED of 30 mg/kg. In the rat formalin test of tonic nociception, gabapentin dose-dependently (30-300 mg/kg) and selectively blocked the late phase with a MED of 100 mg/kg. However, it failed to block carrageenan-induced paw oedema. The intracerebroventricular (ICV) administration of the glycine/NMDA receptor agonist D-Serine, dose-dependently (10-100 micrograms/animal) reversed the antinociceptive action of gabapentin (200 mg/kg, SC). D-Serine (30 micrograms/animal, ICV) also reversed the anxiolytic-like effects (in the light/dark box and the rat elevated X-maze) of gabapentin (30 mg/kg). In contrast, L-Serine (100 micrograms, ICV) failed to block the antinociceptive action of gabapentin. The antinociceptive action of (+)-HA-966 (25 mg/kg, SC), a partial agonist at the glycine/NMDA receptor, was reversed by D-Serine (100 micrograms/animal, ICV). However, D-Serine (100 micrograms/animal, ICV) failed to affect the antinociceptive action of a competitive NMDA receptor antagonist CGS 19755 (3 mg/kg, SC). Gabapentin has negligible affinity for the strychnine insensitive [3H]glycine binding site. This indicates that the interaction between gabapentin and D-Serine may not involve the NMDA receptor complex. Gabapentin may represent a novel type of anxiolytic and analgesic agent.

Does the presence of heparin and dexamethasone in the vitrectomy infusate reduce reproliferation in proliferative vitreoretinopathy?

BACKGROUND

Reproliferation following vitrectomy for proliferative vitreoretinopathy (PVR) causes redetachment in up to 55% of cases. Heparin and corticosteroids have each been shown to inhibit the development of proliferative vitreoretinopathy (PVR) in experimental models. However, little information is available on the use of these agents in humans.

METHODS

In this pilot study, 62 eyes of 62 patients with severe PVR requiring vitrectomy were prospectively randomized to receive either BSS Plus (control) or BSS Plus with heparin and dexamethasone (HD) in the infusate.

RESULTS

After one operation, the retina was reattached in 42 (71%) of 59 eyes: 22 (65%) of 34 eyes in the control group and 20 (80%) of 25 eyes in the HD group (P = 0.16). Reproliferation developed in 26.5% of the control group (9 of 34 eyes) and 16% of the HD group (4 of 25 eyes; P = 0.26). Postoperative hemorrhage was significantly more frequent in the HD group (P = 0.02) but did not influence final visual or anatomic outcome. Hypotony was less frequent in the HD group but the difference was not significant (P = 0.063).

CONCLUSION

The trend from this randomized pilot study suggests that HD supplementation of the vitrectomy infusate may reduce the reproliferation rate in PVR and possibly reduce the rate of hypotony. Postoperative hemorrhage was more frequent with HD but did not cause redetachment or alter visual outcome. A multicenter trial involving more patients would be required to better evaluate the efficacy of HD as a pharmacologic adjunct to PVR surgery.

Usefulness of banding of the pulmonary trunk with single ventricle physiology at risk for subaortic obstruction

This study addresses the effects of early banding of the pulmonary trunk and subsequent management of subaortic obstruction on the attainment of acceptable pre-Fontan hemodynamics in patients with a single left ventricle and aorta arising from an outflow chamber. We report our experience with 26 patients seen at our institution between January 1984 and December 1994 with a diagnosis of double-inlet left ventricle or tricuspid atresia and transposed great arteries, who were initially managed with pulmonary artery banding in the first 6 months of life. Pulmonary artery band placement was performed at an age of 2.1 +/- 1.8 months (mean +/- SD). Associated aortic arch abnormalities were present in 8 patients (31%). There were 19 patients (73%) who underwent treatment with a Damus-Kaye-Stansel procedure or ventricular septal defect (VSD) enlargement for a significant subaortic gradient or morphologically small VSD, alone or in conjunction with a Glenn or Fontan procedure. Eighteen of 26 patients (69%) underwent cardiac catheterization to assess their candidacy for the Fontan operation. Of this group, 16 were classified as low to moderate risk and 2 as high-risk Fontan candidates, based on hemodynamic criteria. The cumulative mortality for the entire cohort was 19%. Our results suggest that this high-risk group of patients can undergo effective pulmonary artery banding as an initial palliative step, with subsequent intervention for subaortic ob- struction when it is documented or highly suspected, and that acceptable pre-Fontan hemodynamic parameters can be achieved.

NADPH diaphorase activity in peptidergic neurones of the parasitic nematode, Ascaris suum

The histochemical marker for nitric oxide synthase, NADPH diaphorase, is known to co-localize in mammalian neurones with various classical neurotransmitters and neuropeptides. The nervous system of the parasitic nematode Ascaris suum has previously been shown to contain both NADPH diaphorase activity and neuropeptide immunoreactivity. This study examined the possibility that NADPH diaphorase and neuropeptide immunoreactivity may co-exist in the same neurones. Two antisera were used, one raised to KYSALMFamide, a C-terminal synthetic analogue of SALMFamide 1 (GFNSALMFamide), and another that recognizes calcitonin-gene-related peptide (CGRP). We provide evidence that in a distinct subset of neurones in the ventral, dorsal and lateral ganglia NADPH diaphorase staining and SALMFamide-like immunoreactivity are co-localized, suggesting a possible role for nitric oxide in modulating neuropeptide activity in these regions. CGRP-like immunoreactivity was less widely distributed, and was not consistently co-localized with NADPH diaphorase.

The FMRFamide-like neuropeptide AF2 is present in the parasitic nematode Haemonchus contortus

Peptides belonging to the FMRFamide family are widely distributed amongst invertebrates. We report here on the isolation of the FMRFamide neuropeptide AF2 (Lys-His-Glu-Tyr-Leu-Arg-Phe-NH2) from the parasitic nematode Haemonchus contortus. Immunocytochemical techniques showed that FMRFamide-like material was distributed in several regions of these organisms including nerve cords and cell bodies of the central nervous system. AF2 was isolated using a method that employed 6 steps of reverse-phase HPLC. The concentration of AF2 in this organism was approximately 30 pmol/g of nematode.

Anomalous origin of the left main pulmonary artery from the ascending aorta associated with DiGeorge syndrome

We place on record 2 infants with the DiGeorge syndrome and anomalous origin of the left pulmonary artery from the ascending aorta. We postulate that: (1) embryogenesis of anomalous origin of the left pulmonary artery from the ascending aorta might be due to the persistent fifth aortic arch connecting both arterial systems; (2) an anomalous pulmonary artery arising from the ascending aorta is part of the aortic arch abnormality accompanied by normal conotruncal septation; and (3) in the DiGeorge syndrome, cardiac anomalies that originate from the conotruncus or aortic arch, or both, may have the same embryologic mechanisms.

Histochemical mapping of NADPH diaphorase in the nervous system of the parasitic nematode Ascaris suum

NADPH diaphorase has recently been discovered to be responsible for neuronal nitric oxide (NO) synthase activity in mammals. It thus serves as a histochemical marker for the localization of NO synthase in the nervous system. The histochemical technique was used to map out potential NO-producing neurones in the nervous system of the parasitic nematode, Ascaris suum. Positive staining for NADPH diaphorase was present in various parts of the central nervous system, in particular within selective cell bodies and fibres in the ventral ganglion, the retrovesicular ganglion, ventral and dorsal cords and sublateral lines. Intense staining was also present in the motorneurone commissures, indicating a potential role for NO as a neurotransmitter at the neuromuscular junction. NADPH disphorase-positive neurones were not confined to the central nervous system. Selective staining was also present in the enteric nervous system, in particular the pharynx and in the peripheral nervous system innervating the sensory organs.

Factors influencing survival in patients undergoing the bidirectional Glenn anastomosis

The bidirectional Glenn anastomosis (BGA) has long been used as a surgical intervention for patients with single ventricle physiology. Initially, this procedure was the final stage in palliation and was performed in older children. Eventually, as the Fontan procedure came to be used as a method to separate circulations, the Glenn procedure was performed as an intermediate step. Over time, the BGA was performed as an alternative for patients who were considered to be at high risk with the Fontan procedure. Between January 1, 1988, and January 1, 1994, 129 patients underwent BGA at the University of California-Los Angeles. These patients were reviewed retrospectively, including clinic visits, catheterization, and echocardiographic information. The overall survival rate was 87% (112 of 129 patients). The average length of follow-up was 27 months. This information was then analyzed by univariate and multivariate analysis. Several factors were related to failure in patients who underwent BGA including pulmonary artery pressure, systemic right ventricle, and presence of anomolous pulmonary venous drainage and heterotaxy syndrome.

The effect of the nematode peptides SDPNFLRFamide (PF1) and SADPNFLRFamide (PF2) on synaptic transmission in the parasitic nematode Ascaris suum

The action of two peptides isolated from the nematode Panagrellus redivivus, PF1 (SDPNFLRFamide) and PF2 (SADPNFLRFamide) have been studied on synaptic transmission in the motornervous system of the parasitic nematode Ascaris suum. Intracellular recordings were made from Ascaris somatic muscle cells and excitatory junction potentials (EJPs) elicited by stimulation of the ventral nerve cord. The EJPs were cholinergic as they were blocked by the Ascaris nicotinic receptor antagonist, benzoquinonium. PF1 caused a slow hyperpolarization, similar to the action of this peptide first reported by Bowman, Geary & Thompson (1990) and further characterized by Franks et al. (1994). The hyperpolarization was accompanied by a marked decrease in the amplitude of the EJPs with an EC50 of 311 +/- 30 nM (n = 5). This inhibition is unlikely to be due to a post-synaptic site of action of the peptide as the muscle cell input conductance was not significantly altered by PF1 and furthermore the response to bath-applied acetylcholine was not inhibited by PF1 at concentrations up to 10 microM (n = 6). PF2 also inhibited the EJPs in a similar manner to PF1. These studies indicate that both of the peptides isolated from the free-living nematode Panagrellus redivivus have biological activity in the parasitic nematode Ascaris suum. PF1 and PF2 have inhibitory actions in contrast to the predominantly excitatory actions of the Ascaris endogenous peptides AF1 (KNEFIRFamide) and AF2 (KHEYLRFamide). The potent actions of the Panagrellus neuropeptides PF1 and PF2 in Ascaris suggest that peptides with a similar or identical sequence may also occur in Ascaris and have an inhibitory role in the motornervous system.

The effects of the nematode peptide, KHEYLRFamide (AF2), on the somatic musculature of the parasitic nematode Ascaris suum

AF2 is an endogenous RFamide-like peptide from the parasitic nematode Ascaris suum. The potent stimulatory effects of this peptide on the somatic musculature of Ascaris strongly suggest that it may have an important role in the motornervous system. Here we have investigated the possibility that AF2 may elicit a stimulatory action on Ascaris muscle by potentiating the actions of the excitatory cholinergic motonervous system either pre-synaptically, post-synaptically or both. In in vitro pharmacological experiments AF2 produced a dose-dependent increase in the frequency and amplitude of spontaneous contractions of Ascaris muscle strip which lasted for more than 1 h after a 3 min application of AF2 (10 nM-10 microM; N = 7). In addition, AF2 (100 nM) potentiated the contraction elicited by ACh by 43 +/- 9% (P < 0.01; N = 8). In electrophysiological recordings from muscle cells, AF2 (10-100 nM; N = 10) potentiated the amplitude of EJPs (excitatory junction potentials). For 100 nM AF2, the potentiation of the EJP was 218 +/- 48% (N = 7; P < 0.01). This effect reversed after a wash of 10 min. AF2 did not potentiate the depolarization of the muscle cell elicited by bath applied ACh. These latter two observations are consistent with a presynpatic action of AF2. AF2 (10-100 nM) generated spontaneous muscle cell action potentials in previously quiescent cells. This effect took more than 1 h to wash out. These observations are discussed in terms of the paralysis of Ascaris that is elicited by AF2.

'Ceruminoma'--a defunct diagnosis

The clinical and pathological features of glandular tumours of the external auditory meatus are presented. Their heterogenous clinical and pathological features make the collective term 'ceruminoma' ambiguous and misleading. The spectrum of pathological behaviour and histological features demonstrated by these interesting tumours necessitate a broader classification system. In our hospital 32 patients presented with tumours of the external auditory meatus over a 30-year period, of which seven were glandular in origin. A review of the histology of these glandular tumours enabled us to reclassify them as adenoma, cylindroma, adenoid cystic carcinoma or ceruminous adenocarcinoma. Together with the less common mucoepidermoid carcinoma and pleomorphic adenoma this subdivision forms a basis for a more meaningful classification system with prognostic and therapeutic implications specific to each tumour type. The term 'ceruminoma' should no longer be used unqualified.

Mycobacterium marches back

The resurgence of tuberculosis world-wide and its association with HIV infection means a greater likelihood of otolaryngologists encountering the disease in one form or another. In this review the features of primary and secondary tuberculosis in various head and neck sites are described, and recent advances in diagnosis are discussed. For the otolaryngologists other important aspects such as infections with atypical mycobacteria, the differential diagnosis of cervical lymphadenopathy in HIV-infected patients, recently recognized problems in drug treatment, and the role of surgery in head and neck tuberculosis are also discussed.

Conversion of atriopulmonary to cavopulmonary anastomosis in management of late arrhythmias and atrial thrombosis

The original atriopulmonary connection or "classic" Fontan operation is associated with several late complications such as arrhythmias, right atrial dilatation, and thromboembolism. This report describes our experience with 3 patients who presented with the acute onset of atrial arrhythmias and upon further evaluation were found to have significant hemodynamic lesions. After failing medical management, all 3 patients were treated successfully with surgical conversion of their atriopulmonary connection to a lateral tunnel cavopulmonary Fontan. The postoperative course of these patients was uneventful. However, long-term evaluation is needed to assess the efficacy of this technique in the prevention of postoperative morbidity.