Co-association of parkin and alpha-synuclein

Parkin and alpha-synuclein are two proteins that are associated with the pathophysiology of Parkinson's disease (PD). Parkin is present in Lewy bodies and axonal spheroids in brains affected by PD, and mutations in parkin cause hereditary forms of Parkinsonism. Alpha-synuclein is a major component of Lewy bodies and is associated with rare cases of PD. We now show that parkin binds to alpha-synuclein, including conditions associated with alpha-synuclein aggregation. Parkin and alpha-synuclein complexes were observed in BE-M17 cells under basal conditions, in BE- M17 cells under oxidative conditions and in brains from control or PD donors. Double staining of PD brains shows parkin and alpha-synuclein co-localize to the same pathological structures (both Lewy bodies and axonal spheroids). These results suggest that parkin interacts with alpha-synuclein and could contribute to the pathophysiology of PD more generally than was previously considered.

Ionization waves in electron-beam-assisted, shielded capillary discharge

A theory of propagation of cathode-directed ionization waves during the early stages of an electrical breakdown in a shielded, low-pressure capillary is developed. The discharge process occurs due to the ionization of the low-density gas in the capillary by an electron beam that is emanating from a hollow cathode. Due to the strong electric field in the capillary the electrons are in the fast acceleration regime. Consequently, the full momentum equation for the electrons is employed, rather than the electron drift velocity approach. The smallness of the ratio of the capillary radius to the characteristic length of the electric potential variation in the axial direction allows the construction of a quasi-one-dimensional model. The latter retains the important two-dimensional nature of the electron flow as well as the electrodynamic boundary conditions at the capillary wall and the conducting shield and results in a set of one-dimensional, time-dependent partial differential equations for the on-axis distributions of the physical quantities. It is shown that those equations admit self-similar solutions that represent ionization waves propagating with constant velocities. The resulting set of ordinary differential equations is solved numerically for various initial conditions representing a nonperturbed steady state ahead of the ionization front and the resulting features of the ionization waves are investigated and discussed. The obtained solutions describe both ionization growth and virtual anode propagation and represent fast ionization waves in plasma waveguides, for which the maximum value of the mean electron velocity is much higher than the wave velocity. The space-charge distribution associated with the ionization waves is found in the form of plasma oscillations with a continuously increasing frequency and a solitary envelope. The calculated wave velocity increases with the gas pressure and this tendency is in agreement with corresponding experimental observations.

Parkin is metabolized by the ubiquitin/proteosome system

Mutations in the parkin gene cause autosomal recessive juvenile parkinsonism. Immunostaining of substantia nigra sections from sporadic Parkinson's disease (PD) cases shows that Parkin accumulates in axonal spheroids and in some Lewy bodies. Because ubiquitin is a major component of Lewy bodies and axonal spheroids, we investigated whether Parkin is metabolized via the ubiquitin/proteosomal pathway. Treatment of BE-M17 neuroblastoma cells with the proteosomal inhibitor, MG132, produced a band corresponding to di-ubiquitinated Parkin that was apparent by immunoblot using two different anti-Parkin antibodies. This higher mol. wt band also co-immunoprecipitated with Parkin. These data suggest that Parkin plays a role in the pathophysiology of sporadic PD, and that Parkin is a substrate for ubiquitination that is degraded by the proteosomal complex.

alpha-Synuclein shares physical and functional homology with 14-3-3 proteins

alpha-Synuclein has been implicated in the pathophysiology of many neurodegenerative diseases, including Parkinson's disease (PD) and Alzheimer's disease. Mutations in alpha-synuclein cause some cases of familial PD (Polymeropoulos et al., 1997; Kruger et al., 1998). In addition, many neurodegenerative diseases show accumulation of alpha-synuclein in dystrophic neurites and in Lewy bodies (Spillantini et al., 1998). Here, we show that alpha-synuclein shares physical and functional homology with 14-3-3 proteins, which are a family of ubiquitous cytoplasmic chaperones. Regions of alpha-synuclein and 14-3-3 proteins share over 40% homology. In addition, alpha-synuclein binds to 14-3-3 proteins, as well as some proteins known to associate with 14-3-3, including protein kinase C, BAD, and extracellular regulated kinase, but not Raf-1. We also show that overexpression of alpha-synuclein inhibits protein kinase C activity. The association of alpha-synuclein with BAD and inhibition of protein kinase C suggests that increased expression of alpha-synuclein could be harmful. Consistent with this hypothesis, we observed that overexpression of wild-type alpha-synuclein is toxic, and overexpression of alpha-synuclein containing the A53T or A30P mutations exhibits even greater toxicity. The activity and binding profile of alpha-synuclein suggests that it might act as a protein chaperone and that accumulation of alpha-synuclein could contribute to cell death in neurodegenerative diseases.

Experience with breast biopsies using the Advanced Breast Biopsy Instrumentation system

OBJECTIVE

A retrospective review of our experience with advanced breast biopsy instrumentation (ABBI) was undertaken to evaluate its efficacy for excisional breast biopsy of lesions detected on mammography. To our knowledge, experience with ABBI has not been previously reported in the radiology literature.

MATERIALS AND METHODS

Biopsies using the ABBI system and an adapted dedicated table were performed in 53 patients who had 54 mammographically evident lesions. Samples were obtained with cannulas ranging in size between 5 and 20 mm. Indications for biopsy were calcifications (n = 22) and masses (n = 31).

RESULTS

Forty-five specimens (44 patients) had benign results at pathology: 15 specimens were diagnosed as fibroadenoma, 15 as cystic breast disease, and four as reactive lymph nodes; the remaining 11 specimens had benign diagnoses of adenosis, fibrosis, and hyperplasia. The average specimen size was 4.8 cm in greatest longitudinal dimension. One patient had a nondiagnostic biopsy for calcifications later found to be dermal. Seven patients were diagnosed as having breast cancer; in six of these, the tumor involved the margins of the specimen. One patient had marked atypia that required reexcision for the diagnosis of intraductal carcinoma to be made.

CONCLUSION

The ABBI procedure is a more invasive and less readily available procedure than core needle biopsy for sampling of benign breast lesions. In seven cases of malignancy diagnosed at breast biopsy, the ABBI technique completely excised only a single lesion. In our experience, the ABBI procedure offered no advantages over core needle biopsy for either benign or malignant lesions.

Staging and IgA VCA titre in patients with nasopharyngeal carcinoma: changes over a 12-year period

The distributions of 2093 patients with nasopharyngeal carcinoma (NPC), by stage, over a 12-year-period did not show any evidence of a shift towards early stages despite growing awareness of this prevalent malignancy. The IgA VCA titre was determined for 1880 of these patients. The median titre increased from 40 in stage I to 80 in stages II, III, and IV, before rising to 160 in stage V. The percentage of patients with a titre > or = 320 increased steadily with advancing stages. Within the same disease stage, the percentage of patients having a particular titre value and the median titre varied considerably from year to year. Better education of the general population and a better serological marker for screening are needed for the early detection of NPC.

The clinical spectrum of rudimentary meningocele

Rudimentary meningocele is rare, only 50 cases having been reported. Clinically it may simulate dermoid cyst, lipoma, or nevus sebaceous. We present two cases of this uncommon condition, each with its own unique clinical features.

Nasopharyngeal carcinoma---time lapse before diagnosis and treatment

This is a descriptive study of 168 patients with nasopharyngeal carcinoma who were referred to public oncology departments for primary treatment between July and September 1996. The mean duration from the onset of the symptoms to histological diagnosis was 5.0 months; the duration ranged from 6.1 months (for patients presenting with nasal symptoms) to 1.8 months (for those with cranial nerve dysfunction). The mean period between the onset of symptoms and the seeking of medical advice was 2.9months. For 54% of the patients, there was a further delay of up to 2.4 months between the initial medical consultation and referral to the appropriate specialist. The majority (84%) of patients attended public institutions for histological confirmation. The mean total time taken from the onset of symptoms to the commencement of radiotherapy was 6.5 months (range, 1.3-74.0 months)---45% of the delay was attributed to the patient, 20% to initial consultations, 14% to diagnostic arrangement, and 21% to preparation for radiotherapy. Concerted efforts are needed to minimise further the time between the onset of symptoms and treatment. A substantial reduction in this delay can be achieved if both public and primary care doctors were made more aware of the significance of relevant symptoms.

Characterization of glucose-specific catabolite repression-resistant mutants of Bacillus subtilis: identification of a novel hexose:H+ symporter

Insertional mutagenesis was conducted on Bacillus subtilis cells to screen for mutants resistant to catabolite repression. Three classes of mutants that were resistant to glucose-promoted but not mannitol-promoted catabolite repression were identified. Cloning and sequencing of the mutated genes revealed that the mutations occurred in the structural genes for (i) enzyme II of the phosphoenolpyruvate-glucose phosphotransferase (PtsG), (ii) antiterminator GlcT, which controls PtsG synthesis, and (iii) a previously uncharacterized carrier of the major facilitator superfamily, which we have designated GlcP. The last protein exhibits greatest sequence similarity to the fucose:H+ symporter of Escherichia coli and the glucose/galactose:H+ symporter of Brucella abortus. In a wild-type B. subtilis genetic background, the glcP::Tn10 mutation (i) partially but specifically relieved glucose- and sucrose-promoted catabolite repression, (ii) reduced the growth rate in minimal glucose medium, and (iii) reduced rates of [14C]glucose and [14C]methyl alpha-glucoside uptake. In a delta pts genetic background no phenotype was observed, suggesting that expression of the glcP gene required a functional phosphotransferase system. When overproduced in a delta pts mutant of E. coli, GlcP could be shown to specifically transport glucose, mannose, 2-deoxyglucose and methyl alpha-glucoside with low micromolar affinities. Accumulation of the nonmetabolizable glucose analogs was demonstrated, and inhibitor studies suggested a dependency on the proton motive force. We conclude that B. subtilis possesses at least two distinct routes of glucose entry, both of which contribute to the phenomenon of catabolite repression.

Muscle dysmorphia. An underrecognized form of body dysmorphic disorder

In the course of several ongoing studies, the authors have encountered men and women who display a form of body dysmorphic disorder in which they become pathologically preoccupied with their degree of muscularity. This condition, which the authors have tentatively termed "muscle dysmorphia," may cause severe subjective distress, impaired social and occupational functioning, and abuse of anabolic steroids and other substances. Epidemiologic data suggest that muscle dysmorphia, though rarely recognized, may afflict substantial numbers of Americans. The authors summarize the features of muscle dysmorphia, present several case examples, and offer proposed diagnostic criteria that may be useful for subsequent research.

Concurrent subarachnoid haemorrhage and myocardial injury

PURPOSE

Subarachnoid haemorrhage is frequently associated with myocardial injury and dysfunction. This report describes such a case, reviews the understanding of this phenomenon, and discusses the implications for timing of surgical clipping of intracranial aneurysm in patients with concurrent myocardial damage.

CLINICAL FEATURES

A 64-yr-old women presented with syncope and congestive heart failure. A diagnosis of subarachnoid haemorrhage was made three days following the initial diagnosis of myocardial infarction. The patient presented for clipping of an intracranial aneurysm on day 36, after her cardiac status had stabilized. No new myocardial ischaemic events occurred, either intra-operatively or post-operatively. Ultimate neurological recovery was poor.

CONCLUSIONS

This case report demonstrates four important aspects of the clinical course of patients with concurrent subarachnoid haemorrhage and myocardial damage: 1) On presentation, cardiac features may predominate, and delay diagnosis and treatment of the underlying subarachnoid haemorrhage. 2) Left ventricular dysfunction, although dramatic, is usually transient. 3) There is confusion regarding the appropriate cardiac risk assessment and management in such patients when presenting for surgery. 4) Long-term morbidity is most often related to neurological, not medical, complications.

Significant prognosticators after primary radiotherapy in 903 nondisseminated nasopharyngeal carcinoma evaluated by computer tomography

PURPOSE

To evaluate the significant prognosticators in nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

From 1984 to 1989, 903 treatment-naive nondisseminated (MO) NPC were given primary radical radiotherapy to 60-62.5 Gy in 6 weeks. All patients had computed tomographic (CT) and endoscopic evaluation of the primary tumor. Potentially significant parameters (the patient's age and sex, the anatomical structures infiltrated by the primary lesion, the cervical nodal characteristics, the tumor histological subtypes, and various treatment variables were analyzed by both monovariate and multivariate methods for each of the five clinical endpoints: actuarial survival, disease-free survival, free from distant metastasis, free from local failure, and free from regional failure.

RESULTS

The significant prognosticators predicting for an increased risk of distant metastases and poorer survival included male sex, skull base and cranial nerve(s) involvement, advanced Ho's N level, and presence of fixed or partially fixed nodes or nodes contralateral to the side of the bulk of the nasopharyngeal primary. Advanced patient age led to significantly worse survival and poorer local tumor control. Local and regional failures were both increased by tumor infiltrating the skull base and/or the cranial nerves. In addition, regional failure was increased significantly by advancing Ho's N level. Parapharyngeal tumor involvement was the strongest independent prognosticator that determined distant metastasis and survival rates in the absence of the overriding prognosticators of skull base infiltration, cranial nerve(s) palsy, and cervical nodal metastasis.

CONCLUSIONS

The significant prognosticators are delineated after the advent of CT and these should form the foundation of the modern stage classification for NPC.

Strong association between hyperferritinaemia and metastatic disease in nasopharyngeal carcinoma

We have investigated the role of serum ferritin, in relation to disease stages, in patients with nasopharyngeal carcinoma. Patients with localised disease (Ho's stage I-IV) had levels which were not significantly different from age, sex matched normal subjects and there was no relationship between mean serum ferritin levels and stage. However, in patients with metastatic disease levels were grossly elevated with mean levels increased more than 6-fold compared to normal subjects and patients with localised disease. Furthermore, among the small group of patients with localised disease but hyperferritinaemia, the subsequent development of metastatic disease within 1 year was significantly much higher (32.4%) than in those with levels falling within the reference range (10.3%). Hyperferritinaemia is strongly associated with, and may predict, metastatic disease in patients with nasopharyngeal carcinoma.

Early tumour response and treatment toxicity after hyperfractionated radiotherapy in nasopharyngeal carcinoma

The aim of the present study was to undertake a planned interim analysis of a prospective randomized trial comparing the tumour response and the acute and subacute complications of hyperfractionated radiotherapy and conventional radiotherapy in non-metastatic nasopharyngeal carcinoma (NPC). 100 patients with newly diagnosed non-metastatic NPC were randomized to receive either conventional radiotherapy (Arm I) or hyperfractionated radiotherapy (Arm II). Stratification was done according to the T-Stage (modified Ho's T-Stage classification). The biological effective dose (10 Gy) to the primary and the upper cervical lymphatics were 75.0 and 73.1 for Arm I and 84.4 and 77.2 for Arm II, respectively. Hyperfractionated radiotherapy was associated with significant mucositis which is of higher grade than conventional radiotherapy (p = 0.0001), but the duration of mucositis was similar between the two Arms and all study patients completed radiotherapy on schedule without interruption of radiotherapy. Early survival and tumour recurrence rates were comparable between the Arms. The preliminary results indicate that the hyperfractionated radiotherapy has excellent patient compliance in Chinese patients, with acceptable acute and subacute toxicities and the local and regional complete tumour response rates being comparable with conventional radiotherapy. The significance of the time required after start of radiotherapy to achieve a complete tumour response is discussed.

Transcription of the glutamyl-tRNA reductase (hemA) gene in Salmonella typhimurium and Escherichia coli: role of the hemA P1 promoter and the arcA gene product

In Salmonella typhimurium and Escherichia coli, the hemA gene encodes the enzyme glutamyl-tRNA reductase, which catalyzes the first committed step in the heme biosynthetic pathway. It has recently been reported that a lac operon fusion to the hemA promoter of E. coli is induced 20-fold after starvation for heme. Induction was dependent on the transcriptional regulator ArcA, with a second transcriptional regulator, FNR, playing a negative role specifically under anaerobic conditions (S. Darie and R. P. Gunsalus, J. Bacteriol. 176:5270-5276, 1994). We have investigated the generality of this effect by examining the response to heme starvation of a number of lac operon fusions to the hemA promoters of both E. coli and S. typhimurium. We confirmed that such fusions are induced during starvation of a hemA auxotroph, but the level of induction observed was maximally sixfold and for S. typhimurium fusions it was only two- to fourfold. Sequences required for high-level expression of hemA lie within 129 bp upstream of the major (P1) promoter transcriptional start site. Mutants defective in the P1 promoter had greatly reduced hemA-lac expression both in the presence and in the absence of ALA. Mutations in arcA had no effect on hemA-lac expression in E. coli during normal growth, although the increase in expression during starvation for ALA was half that seen in an arcA+ strain. Overexpression of the arcA gene had no effect on hemA-lac expression. Primer extension analysis showed that RNA 5' ends mapping to the hemA P1 and P2 promoters were not expressed at significantly higher levels in induced cultures. These results differ from those previously reported.

A retrospective study of the role of intracavitary brachytherapy and prognostic factors determining local tumour control after primary radical radiotherapy in 903 non-disseminated nasopharyngeal carcinoma patients

The aims of this retrospective study were to determine the role of intracavitary brachytherapy given shortly after external beam radiotherapy in the primary radical treatment of non-metastatic nasopharyngeal (NPC) cancer patients, and the prognostic factors governing local tumour control. From 1984 to 1989, 903 patients with non-disseminated NPC who had had no previous treatment were managed at the Prince of Wales Hospital, where investigation and treatment methods had been standardized according to a departmental protocol. The external radiotherapy dose of 60.0-62.5 Gy in 6 weeks was given to all patients. Parapharyngeal booster radiotherapy with a single photon beam to 20 Gy in 2 weeks was given to those with parapharyngeal tumour extension. Computed tomography of the nasopharynx and skull base, and pretreatment nasopharyngoscopy and biopsy were performed in all patients. Nasopharyngoscopy was repeated at 4 weeks after the last day of external irradiation. Local persistence in 99 patients was treated additionally by intracavitary brachytherapy to 24 Gy in three fractions over 15 days. Fifty-one patients with early stage primary disease (Ho Stage T1 and T2n (nasal)) who responded completely to external radiotherapy were given adjuvant intracavitary brachytherapy to 18 Gy in three fractions over 15 days. Intracavitary therapy was an inadequate salvage treatment for the locally persisting T3, T20 (oropharyngeal) and T2p (parapharyngeal) disease, but there was a trend towards improved local control after intracavitary brachytherapy for the locally persisting T1 tumours. Adjuvant brachytherapy did not enhance local tumour control for the early T-stage tumours that completely responded to external radiotherapy. Both forms of intracavitary brachytherapy were safe with few and acceptable complications. In the 903 non-disseminated NPCs, the patient's age and tumour involvement of the skull base and cranial nerves were significant independent prognostic factors governing local tumour control. In the 358 patients with Ho T3 disease, tumour involvement of the orbits and the laryngopharynx significantly worsened local tumour control. The presence of local persistence at 4 weeks after external radiotherapy, for which therapeutic brachytherapy was given, was marginally significant as a prognostic factor in addition to the presence of cranial nerve palsy.

Interaction of manganese-mesoporphyrin with oleic acid vesicles

We investigated the interaction between manganese(III)mesoporphyrin (MnMeso), a metalloporphyrin, and liposome membranes containing oleic acid (OA; cis-9-octadecenoic acid). MnMeso associates preferentially with OA but minimally with egg phosphatidylcholine (EPC). Using small unilamellar vesicles, we characterized the MnMeso-OA binding at neutral pH. Our data suggest that MnMeso binds to the OA bilayer with Kd = 6.8 x 10(-4) M; the binding stoichiometry of MnMeso-OA was 1:3.4. This OA-MnMeso interaction was analyzed further for changes in the T1 relaxation property of MnMeso. OA increased the T1 of MnMeso significantly more than did EPC, suggesting that the OA-MnMeso interaction was stronger than that of PC-MnMeso. The side-chain specificity of the OA interaction with this porphyrin derivative was further supported in an experiment with manganese mesotetra(4-sulfonatophenyl)porphine, which lacks hydrophobic side chains for OA interaction. The association of MnMeso with the OA membrane was proposed according to the structure of MnMeso and OA and further verified using electron microscopy. A strong association of MnMeso with OA, an absorption enhancer of the gastrointestinal tract, may be useful for delivery of MnMeso as an oral contrast agent for magnetic resonance imaging.

Afterloading radiotherapy for local persistence of nasopharyngeal carcinoma

71 patients suffering from local persistence of nasopharyngeal carcinoma after primary external radiotherapy were treated by afterloading intracavitary 192Ir. 66 (93.0%) had a complete response as evidenced by fibreoptic nasopharyngoscope examination and biopsy 4 weeks after the treatment. Significant prognosticators were studied by both monovariate and multivariate analysis. The early overall clinical stage at first presentation predicted a favourable survival. Local tumour control was adversely affected by advanced T-stage at first presentation, and by using a single 192Ir source, unilaterally applied to treat only one side of the nasopharynx. The intracavitary treatment was tolerated well and treatment complications were confined to the nasopharynx: chronic radiation ulceration (five patients) and diffuse telangiectasia (three patients).

Multicenter phase II trial of mitoxantrone in patients with advanced nasopharyngeal carcinoma in Southeast Asia: an Asian-Oceanian Clinical Oncology Association Group study

PURPOSE

Patients with advanced nasopharyngeal carcinoma (NPC) have a high incidence of recurrence and often develop distant metastases despite local control. This prospective multicenter phase II trial was conducted to evaluate the safety and efficacy of Novantrone (mitoxantrone; Lederle Laboratories, Wayne, NJ) in the therapy of patients with advanced NPC.

PATIENTS AND METHODS

One hundred eight patients with advanced NPC, namely, those with recurrent or persistent disease following primary radiotherapy, or newly diagnosed metastatic disease, were treated with mitoxantrone. Mitoxantrone was administered intravenously at an initial dose of 12 mg/m2 and repeated every 3 weeks, with dose escalation to a maximum of 14 mg/m2. The distribution of histologic subtypes was representative of NPC, with the majority being (61%) undifferentiated (or anaplastic) carcinoma.

RESULTS

The overall response rate (complete response [CR] and partial response [PR]) was 25% (95% confidence interval, 17% to 33%). The median response duration, time to treatment failure, and survival duration were 140, 82, and 394 days, respectively. Histology (poorly differentiated squamous cell) was found to be the only important factor in predicting response (P = .04) based on a multivariate analysis of nine pretreatment characteristics. The major dose-limiting toxicity was leukopenia. The incidences of nausea/vomiting, alopecia, and stomatitis/mucositis were 34%, 6%, and 3%, respectively. None were severe. Two patients had asymptomatic, moderate Alexander-grade cardiotoxicity.

CONCLUSION

This study represents a large, controlled multicenter trial of single-agent mitoxantrone in the treatment of advanced NPC. Mitoxantrone was well tolerated and produced an overall response rate comparable to that of other single-agent therapies used in the treatment of advanced head and neck cancer. Combination trials with mitoxantrone for advanced disease should be considered.

Absence of p53 gene mutations in primary nasopharyngeal carcinomas

Alterations in the p53 tumor suppressor gene and Epstein-Barr virus status were investigated in 15 nasopharyngeal carcinoma (NPC) biopsies, 4 xenografts, and 2 cell lines from the Cantonese region of southern China. One other established NPC cell line obtained from a northern Chinese patient was also studied. Restriction fragment length polymorphism analysis revealed a loss of heterozygosity for chromosome 17p, where the p53 gene resides, in only one of 15 NPC biopsies. Polymerase chain reaction-single-stranded conformational polymorphism analysis and direct sequencing failed to detect sequence alterations in exons 5 through 8 of the p53 gene in the 15 tumors and in the 4 NPC xenografts, all of which tested positive for Epstein-Barr virus. In contrast, the 3 NPC cell lines were all negative for Epstein-Barr virus and contained G----C transversions in the p53 gene, with cell lines CNE-1 and CNE-2 harboring identical AGA (arginine) to ACA (threonine) changes at codon 280. These results suggest that p53 inactivation is not a necessary component of nasopharyngeal carcinogenesis in Cantonese but may be important in the establishment of cell lines derived from these tumors.