Dorsal cochlear nucleus responses to somatosensory stimulation are enhanced after noise-induced hearing loss

Multisensory neurons in the dorsal cochlear nucleus (DCN) achieve their bimodal response properties [Shore (2005) Eur. J. Neurosci., 21, 3334-3348] by integrating auditory input via VIIIth nerve fibers with somatosensory input via the axons of cochlear nucleus granule cells [Shore et al. (2000) J. Comp. Neurol., 419, 271-285; Zhou & Shore (2004)J. Neurosci. Res., 78, 901-907]. A unique feature of multisensory neurons is their propensity for receiving cross-modal compensation following sensory deprivation. Thus, we investigated the possibility that reduction of VIIIth nerve input to the cochlear nucleus results in trigeminal system compensation for the loss of auditory inputs. Responses of DCN neurons to trigeminal and bimodal (trigeminal plus acoustic) stimulation were compared in normal and noise-damaged guinea pigs. The guinea pigs with noise-induced hearing loss had significantly lower thresholds, shorter latencies and durations, and increased amplitudes of response to trigeminal stimulation than normal animals. Noise-damaged animals also showed a greater proportion of inhibitory and a smaller proportion of excitatory responses compared with normal. The number of cells exhibiting bimodal integration, as well as the degree of integration, was enhanced after noise damage. In accordance with the greater proportion of inhibitory responses, bimodal integration was entirely suppressive in the noise-damaged animals with no indication of the bimodal enhancement observed in a sub-set of normal DCN neurons. These results suggest that projections from the trigeminal system to the cochlear nucleus are increased and/or redistributed after hearing loss. Furthermore, the finding that only neurons activated by trigeminal stimulation showed increased spontaneous rates after cochlear damage suggests that somatosensory neurons may play a role in the pathogenesis of tinnitus.

Extensive venous/lymphatic malformations causing life-threatening haematological complications

BACKGROUND

Large venous/lymphatic slow-flow malformations (SFM) can be associated with a coagulopathy resulting in thrombosis and haemorrhage. Such potentially life-threatening complications of SFM have been reported only rarely.

OBJECTIVES

To better define the clinical characteristics of haematological complications associated with SFM, to highlight the importance of recognition and to discuss the management of these difficult-to-treat patients.

PATIENTS AND METHODS

A cohort of six children who presented with massive SFM associated with serious haematological complications was seen between January 1980 and June 2005 in the Department of Paediatric Dermatology, Great Ormond Street Hospital for Children, London, U.K. (tertiary referral centre for vascular anomalies). Clinical and haematological characteristics were recorded.

RESULTS

Patients were aged 1-20 years. All suffered with recurrent episodes of pain, localized skin necrosis and bleeding. All had intravascular coagulopathy and life-threatening complications. These included brain haemorrhage, massive bleeding from the uterus and colon, large and extensive thromboses of the deep vessels in the abdomen and pelvis and severe haemoptysis. One patient died suddenly at the age of 20 years from pulmonary thromboembolism and thrombosis within the deep vessels of the vascular malformation. The youngest patient underwent a leg amputation to remove the huge vascular malformation due to the major risk of complications and lack of limb function. Three of the patients underwent anticoagulation treatment and showed improvement in their coagulopathy.

CONCLUSIONS

It is essential that patients with extensive SFM have their coagulation screened regularly to detect intravascular coagulopathy. This may progress to disseminated vascular coagulopathy and a serious risk of thrombosis and haemorrhage. Such patients require early anticoagulation in an attempt to prevent these secondary complications.

Four common glomulin mutations cause two thirds of glomuvenous malformations ("familial glomangiomas"): evidence for a founder effect

BACKGROUND

Glomuvenous malformation (GVM) ("familial glomangioma") is a localised cutaneous vascular lesion histologically characterised by abnormal smooth muscle-like "glomus cells" in the walls of distended endothelium lined channels. Inheritable GVM has been linked to chromosome 1p21-22 and is caused by truncating mutations in glomulin. A double hit mutation was identified in one lesion. This finding suggests that GVM results from complete localised loss of function and explains the paradominant mode of inheritance.

OBJECTIVE

To report on the identification of a mutation in glomulin in 23 additional families with GVM.

RESULTS

Three mutations are new; the others have been described previously. Among the 17 different inherited mutations in glomulin known up to now in 43 families, the 157delAAGAA mutation is the most common and was present in 21 families (48.8%). Mutation 108C-->A was found in five families (11.8%), and the mutations 554delA+556delCCT and 1179delCAA were present together in two families (4.7% each). Polymorphic markers suggested a founder effect for all four mutations.

CONCLUSIONS

Screening for these mutations should lead to a genetic diagnosis in about 70% of patients with inherited GVM. So far, a mutation in glomulin has been found in all GVM families tested, thus demonstrating locus homogeneity.

Sternal malformation/vascular dysplasia syndrome with linear hypopigmentation

We report a 7-year-old boy who presented with a facial haemangioma, a circumscribed depression over the sternum, coarctation of the aorta, ventricular septal defect and dysplastic cerebral arteries responsible for an episode of acute infarct. This combination of clinical features has been described as the sternal malformation/vascular dysplasia syndrome or PHACES syndrome. At the age of 5 years, lines of hypopigmentation were noted on the right arm, the right hand and the back, along the lines of Blaschko, with no history of any preceding inflammatory changes, and have persisted unchanged. These pigmentary changes have not previously been reported in association with this syndrome.

Outcome of antenatally suspected congenital cystic adenomatoid malformation of the lung: 10 years' experience 1991-2001

OBJECTIVE

To determine the outcome of antenatally suspected congenital cystic adenomatoid malformation of the lung (CCAM) over a 10 year period.

METHODS

This is a retrospective study of all babies diagnosed antenatally in the Prenatal Diagnosis Unit and delivered in Oxford between 1991 and 2001. Data were obtained from the Oxford Congenital Anomaly Register, theatre records, and histopathology reports.

RESULTS

Twenty eight cases of CCAM were diagnosed antenatally. Five pregnancies were terminated. Data are available on all 23 of the pregnancies that continued and resulted in two neonatal deaths and 21 surviving babies. Eleven of the 23 cases (48%) showed some regression of the lesion antenatally, and four of these cases appeared to resolve completely on prenatal ultrasound. Three of the 23 babies (13%) were symptomatic in the early neonatal period, and three developed symptoms shortly afterwards. Seventeen of the 23 babies (74%) were asymptomatic, of whom 12 had abnormalities on chest radiograph or computed tomography scan and had elective surgery. Two babies (8%) had completely normal postnatal imaging, and three had abnormalities which resolved in the first year of life. Seventeen of the 23 babies (74%) had surgery. Histology at surgery was heterogeneous. Of the 23 live births, all 21 survivors (91%) are well at follow up or have been discharged.

CONCLUSIONS

All babies diagnosed antenatally with CCAM require postnatal imaging with computed tomography irrespective of signs of antenatal resolution. In asymptomatic infants, the recommendations are close follow up and elective surgery for persistent lesions within the first year of life. Histology at surgery was heterogeneous, and this should be considered when counselling parents.

A systemic route for drug loading to lymphatic phagocytes

Lymph nodes are primary germination and proliferation sites for many types of pathogens. Maintaining therapeutic levels of appropriate chemotherapeutic agents in the lymph node tissue is critical for the treatment of both infection and cancer. This study was intended to develop a systemic route for loading lymph node phagocytes with drugs, using a lymph node specific nanocarrier. The latter is assembled as a 10-15 nm particle with a drug-carrying core and a phagocyte-homing poly(1-->6)-alpha-d-glucose based interface. Biokinetics and microdistribution of the model carrier were investigated in vivo. Nanocarrier accumulation in lymph nodes reached 30-35% dose/g in central lymph nodes, with deposition in various phagocytic cell populations. The latter included cells harboring inhaled microparticles translocated to lymph nodes from the lungs. In view of the nanocarrier ability to transport and release significant amounts of various drug substances, the data suggests feasibility of systemic drug loading to lymphatic phagocytes and, through drug release, to the neighboring cells.

Obstetric fistula: the challenge to human rights

Obstetric fistula can be explained to result from different causes. These holes in the tissue wall between the vagina and bladder and/or rectum are most prevalent in resource-poor countries, attributable to prolonged obstructed labour and absent or inaccessible remedial prenatal services. Obstructed labour is often due to small pelvic size, resulting from women's youth and premature childbearing and/or malnutrition. Poverty at national health-service and family levels often predisposes pregnant populations to suffer high rates of fistula. Global estimates showing up to 100,000 new cases each year and 2 million affected girls and women are probably gross underestimates. Fistula devastates lives of sufferers, who are often expelled by husbands and become isolated from their families and communities. Failures of states to provide prenatal preventive care (including medically indicated cesarean deliveries) and timely fistula repair violate women's internationally recognized human rights, especially to healthcare in general and reproductive healthcare in particular.

Synthesis of a Macromolecular Camptothecin Conjugate with Dual Phase Drug Release

A water soluble macromolecular conjugate of camptothecin (CPT) with a new, dual phase hydrolytic drug release mechanism was prepared on the basis of a 60 kDa biodegradable hydrophilic "stealth" polyacetal, poly(1-hydroxymethylethylene hydroxy-methyl formal). Succinamido-glycinate was used as a prodrug releasing group. A model preparation with 7.5% CPT content w/w was water soluble. The lipophilic camptothecin prodrug, camptothecin-(O20)-succinimidoglycinate, was released from the conjugate with t(1/2) = 2.2 +/- 0.1 h in rodent plasma. The blood clearance in a rodent model as measured by CPT was release limited, t(1/2) = 2.1 +/- 0.2 h, while the conjugate half-life was 14.2 +/- 1.7 h. In a xenograft tumor model, the conjugate demonstrated higher antineoplastic efficacy than CPT at a less than equitoxic dose. This improved therapeutic window is in line with the modified drug pharmacokinetics and with camptothecin release in a stabilized lipophilic prodrug form. Regulation of prodrug release and hydrolysis rates through linker structure modification will open the way to further improve both pharmacokinetics and pharmacodynamics.