Chelation and intercalation: complementary properties in a compound for the treatment of Alzheimer's disease

Selective application of metal chelators to homogenates of human Alzheimer's disease (AD) brain has led us to propose that the architecture of aggregated beta-amyloid peptide, whether in the form of plaques or soluble oligomers, is determined at least in part by high-affinity binding of transition metals, especially copper and zinc. Of the two metals, copper is implicated in reactive oxygen species generating reactions, while zinc appears to be associated with conformational and antioxidant activity. We tested the copper chelators trientine, penicillamine, and bathophenanthroline for their ability to mobilize brain Abeta as measured against our benchmark compound bathocuproine (BC). All of these agents were effective in solubilizing brain Abeta, although BC was the most consistent across the range of AD brain tissue samples tested. Similarly, all of the copper chelators depleted copper in the high-speed supernatants. BC alone had no significant effect upon zinc levels in the soluble fraction. BC extraction of brain tissue from C100 transgenic mice (which express human Abeta but do not develop amyloid) revealed SDS-resistant dimers as Abeta was mobilized from the sedimentable to the soluble fraction. NMR analysis showed that, in addition to its copper chelating properties, BC interacts with Abeta to form a complex independent of the presence of copper. Such hybrid copper chelating and "chain breaking" properties may form the basis of a rational design for a therapy for Alzheimer's disease.

Stage III thymoma: pattern of failure after surgery and postoperative radiotherapy and its implication for future study

PURPOSE

With the conventional approach of surgery and postoperative radiotherapy for patients with Masaoka Stage III thymoma, progress has been slow for an improvement in the long-term survival rate over the past 20 years. The objective of this study was to evaluate the pattern of failure and survival after surgery and postoperative radiotherapy in Stage III thymoma and search for a new direction for better therapy outcome.

METHODS AND MATERIALS

Between 1975 and 1993, 111 patients with thymoma were treated at Massachusetts General Hospital. Of these, 32 patients were determined to have Masaoka Stage III thymoma. The initial treatment included surgery for clinically resectable disease in 25 patients and preoperative therapy for unresectable disease in 7 patients. Surgical procedure consisted of thymectomy plus resection of involved tissues. For postoperative radiotherapy (n = 23), radiation dose consisted of 45-50 Gy for close resection margins, 54 Gy for microscopically positive resection margins, and 60 Gy for grossly positive margins administered in 1.8 to 2.0 Gy of daily dose fractions, 5 fractions a week, over a period of 5 to 6.6 weeks. In preoperative radiotherapy, a dose of 40 Gy was administered in 2.0 Gy of daily dose fractions, 5 days a week. For patients with large tumor requiring more than 30% of total lung volume included in the target volume (n = 3), a preoperative radiation dose of 30 Gy was administered and an additional dose of 24-30 Gy was given to the tumor bed region after surgery for positive resection margins.

RESULTS

Patients with Stage III thymoma accounted for 29% (32/111 patients) of all patients. The median age was 57 years with a range from 27 to 81 years; gender ratio was 10:22 for male to female. The median follow-up time was 6 years. Histologic subtypes included well-differentiated thymic carcinoma in 19 (59%), high-grade carcinoma in 6 (19%), organoid thymoma in 4 (13%), and cortical thymoma in 3 (9%) according to the Marino and Müller-Hermelink classification. The overall survival rates were 71% and 54% at 5 and 10 years, respectively. Ten of the 25 patients who were subjected to surgery as initial treatment were found to have incomplete resection by histopathologic evaluation. The 5- and 10-year survival rates were 86% and 69% for patients (n = 15) with clear resection margins as compared with 28% and 14% for those (n = 10) with incomplete resection margins even after postoperative therapy, p = 0.002. Survival rates at 5 and 10 years were 100% and 67% for those with unresectable disease treated with preoperative radiation (n = 6) and subsequent surgery (n = 3). Recurrence was noted in 12 of 32 patients and 11 of these died of recurrent thymoma. Recurrences at pleura and tumor bed accounted for 77% of all relapses, and all pleural recurrences were observed among the patients who were treated with surgery initially.

CONCLUSION

Incomplete resection leads to poor results even with postoperative radiotherapy or chemoradiotherapy in Stage III thymoma. Pleural recurrence is also observed more often among patients treated with surgery first. These findings suggest that preoperative radiotherapy or chemoradiotherapy may result in an increase in survival by improving the rate of complete resection and reducing local and pleural recurrences.

Intelligent support systems in agriculture: how can we do better?

There has been considerable effort and money spent in the development of intelligent support systems (decision support systems and expert systems) for use by farmers, but few systems appear to be adopted for regular use. An examination of the conceptual issues concerning the adoption of innovations, with particular reference to software products, identifies major factors that appear to influence the adoption of these systems by farmers. The conceptual frameworks used for this analysis include Rogers’ diffusion theory, the perceived usefulness and ease-of-use of software, software development methods with a focus on the adopter-based approach to technology, and user involvement in the development of an innovation. As a result of this approach, we argue that the low adoption rate of intelligent support systems is understandable and could have been predicted. Different approaches are needed if we are to do better in the future. These include participatory approaches, using ‘softer’ systems methodologies that acknowledge the importance of involving the user early in the development process and that pay attention to the decision-making styles and social context of potential users.

Leukoencephalopathy and raised brain lactate from heroin vapor inhalation ("chasing the dragon")

BACKGROUND

Inhalation of heated heroin vapor ("chasing the dragon"), which is gaining popularity among drug users seeking to avoid the risks of parenteral drug administration, can produce progressive spongiform leukoencephalopathy.

METHODS

We studied the clinical phenotype and course, MRI, MRS, and brain pathology in the first American patients described with this syndrome.

RESULTS

Two of the three heroin users studied inhaled heroin pyrolysate together daily over the course of 2 weeks. They developed ataxia, dysmetria, and dysarthria. Patient 1 progressed to an akinetic mute state with decorticate posture and subsequent spastic quadriparesis. Patient 2 developed a mild spastic quadriparesis and gait freezing. Patient 3 was asymptomatic following less heroin exposure. Brain MRI showed diffuse, symmetrical white matter hyperintensities in the cerebellum, posterior cerebrum, posterior limbs of the internal capsule, splenium of the corpus callosum, medial lemniscus, and lateral brainstem. MRS showed elevated lactate. Brain biopsy (Patient 1) showed white matter spongiform degeneration with relative sparing of U-fibers; electron microscopy revealed intramyelinic vacuolation with splitting of intraperiod lines. Progressive deterioration occurred in Patients 1 and 2 over 4 weeks. Both were treated with antioxidants including oral coenzyme Q, and clinical improvement occurred. Patient 1 recovered nearly completely over 24 months. Patient 2 improved, but developed a delayed-onset cerebellar hand tremor. Both still have white matter abnormalities on MRI and MRS.

CONCLUSIONS

Elevated lactate in white matter and the possible response to antioxidants suggests mitochondrial dysfunction in progressive spongiform leukoencephalopathy following inhalation of heated heroin vapor.

Type 1 protease resistant prion protein and valine homozygosity at codon 129 of PRNP identify a subtype of sporadic Creutzfeldt-Jakob disease

A man was studied with sporadic Creutzfeldt-Jakob disease (sCJD) who had serial cortical syndromes evolving over 15 months without significant ataxia, prominent myoclonus, or periodic complexes on EEG examinations. This clinical phenotype correlated with a predominantly cortical and striatal distribution of lesions and accumulation of protease resistant prion protein with relative sparing of the brainstem or cerebellum. No amyloid plaques were seen and prion protein (PrP) immunohistochemistry only demonstrated very faint granular deposits in the cerebral cortex. Molecular analysis showed homozygosity for valine at codon 129 in the prion protein gene (PRNP) and protease resistant prion protein type 1 deposition. The comparison of molecular and clinicopathological features of the present case with those previously reported in sCJD, indicates that valine homozygosity at codon 129 and type 1 protease resistant prion protein are associated with a distinct phenotypic variant of sCJD. The data also support the view that the PRNP codon 129 polymorphism and the physicochemical properties of the protease resistant prion protein are major determinants of phenotypic variability in sCJD.

Frequency of tau mutations in three series of non-Alzheimer's degenerative dementia

Splice-site and missense mutations have been identified in tau associated with frontotemporal dementia with parkinsonism linked to chromosome 17. In this study we assessed the genetic contribution of tau mutations to three patient series with non-Alzheimer's (non-AD) degenerative dementia. The groups included (1) a community-based dementia series from Minnesota, MN; (2) a referral series with clinicopathological tauopathy; and (3) a pathologically confirmed familial frontotemporal dementia series from Manchester, UK. Comparing the three clinical series: in the stringently diagnosed Manchester frontotemporal dementia series, tau mutations were present in 13.6% of cases (three splice-site mutations); in the clinicopathological referral series that used more general inclusion criteria, 3 cases with P301L mutations were observed, which represents a lower mutation frequency of 3.6% (9.4% in familial cases); in contrast, tau mutations were not detected in the Minnesota community-based dementia series, suggesting the occurrence of these mutations in dementia generally is rare (<0.2%). These data identify the prevalence of mutations in three different clinical settings and indicate that this figure is sensitive to the diagnostic criteria used in each patient series.

Abnormal microtubule packing in processes of SF9 cells expressing the FTDP-17 V337M tau mutation

Mutations in the gene for the microtubule associated protein, tau have been identified for fronto-temporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17). In vitro data have shown that FTDP-17 mutant tau proteins have a reduced ability to bind microtubules and to promote microtubule assembly. Using the baculovirus system we have examined the effect of the V337M mutation on the organization of the microtubules at the ultrastructural level. Our results show that the organization of the microtubules is disrupted in the presence of V337M tau with greater distances between the microtubules and fewer microtubules per process.

Clinical genetics of familial progressive supranuclear palsy

Recent studies have shown that progressive supranuclear palsy (PSP) could be inherited, but the pattern of inheritance and the spectrum of the clinical findings in relatives are unknown. We here report 12 pedigrees, confirmed by pathology in four probands, with familial PSP. Pathological diagnosis was confirmed according to recently reported internationally agreed criteria. The spectrum of the clinical phenotypes in these families was variable including 34 typical cases of PSP (12 probands plus 22 secondary cases), three patients with postural tremor, three with dementia, one with parkinsonism, two with tremor, dystonia, gaze palsy and tics, and one with gait disturbance. The presence of affected members in at least two generations in eight of the families and the absence of consanguinity suggests autosomal dominant transmission with incomplete penetrance. We conclude that hereditary PSP is more frequent than previously thought and that the scarcity of familial cases may be related to a lack of recognition of the variable phenotypic expression of the disease.

Intracellular accumulation of detergent-soluble amyloidogenic A beta fragment of Alzheimer's disease precursor protein in the hippocampus of aged transgenic mice

To study amyloid beta-protein (A beta) production and aggregation in vivo, we created two transgenic (Tg) mouse lines expressing the C-terminal 100 amino acids of human amyloid precursor protein (APP): Tg C100.V717F and Tg C100.WT. Western blot analysis showed that human APP-C100 and A beta were produced in brain and some peripheral tissues and A beta was produced in serum. Using antibodies specific for the A beta C terminus we found that Tg C100.V717F produced a 1.6-fold increase in A beta42/A beta40 compared with Tg C100.WT. Approximately 30% of total brain A beta (approximately 122 ng/g of wet tissue) was water-soluble. The remaining 70% of A beta partitioned into the particulate fraction and was completely sodium dodecyl sulfate-soluble. In contrast, human Alzheimer's disease brain has predominantly sodium dodecyl sulfate-insoluble A beta. Immunohistochemistry with an A beta(5-8) antibody showed that A beta or A beta-containing fragments accumulated intracellularly in the hippocampus of aged Tg C100.V717F mice. The soluble A beta levels in Tg brain are similar to those in normal human brain, and this may explain the lack of microscopic amyloid deposits in the Tg mice. However, this mouse model provides a system to study the intracellular processing and accumulation of A beta or A beta-containing fragments and to screen for compounds directed at the gamma-secretase activity.

The natural history of CADASIL: a pooled analysis of previously published cases

BACKGROUND AND PURPOSE

Although numerous families with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) have been reported, our understanding of the disease remains incomplete. Thus, we performed this study to investigate the phenotypic range and natural history of CADASIL.

METHODS

We performed a pooled analysis of previously published cases.

RESULTS

We identified 105 symptomatic patients in 33 families. Vascular risk factors were uncommon, with hypertension reported in only 8 patients. The mean age of symptom onset was 36. 7+/-12.9 years. Stroke or transient ischemic attack was an initial symptom in 45 patients, with a mean age of onset of 41.2+/-9.2 years. Migraine was also a common initial symptom, reported by 42 patients at a younger mean age of 28.3+/-11.7 years. Other initial symptoms included depression in 9 patients, cognitive impairment in 6 patients, and seizures in 3 patients. Regarding clinical course, 71 patients experienced a stroke or transient ischemic attack, and 52 of those patients had 1 or more recurrent ischemic events. Dementia was reported in 44 patients. Only 3 additional patients experienced migraine at a later time, while 13 additional patients developed depression. Six patients had seizures. Twenty-two of the 105 patients had died, with a mean age of death of 54.8+/-10.6 years. Nineteen of those 22 patients had experienced a stroke or transient ischemic attack and 19 patients were demented.

CONCLUSIONS

CADASIL typically becomes evident in early or middle adulthood with migraine or an ischemic event, later manifests itself through recurrent subcortical ischemic strokes leading to a stepwise decline and dementia, and results in reduced survival.

Alpha-synuclein expression in substantia nigra and cortex in Parkinson's disease

Mutations in the human alpha-synuclein gene have been identified in several families of European descent with early-onset Parkinson's disease (PD). We sequenced the complete alpha-synuclein cDNA from substantia nigra and cortex from nine patients with PD and eight control subjects. No mutations were found. We then analyzed alpha-synuclein mRNA levels using a ribonuclease protection assay. Two major protected bands of alpha-synuclein mRNA, possibly representing two splice variants of the gene, were observed. Alpha-synuclein mRNA was significantly diminished in the substantia nigra of patients with PD compared with control subjects but not in the cortex. Our findings suggest that decreased synuclein mRNA may be an early alteration in the SN in PD, and imply that decreased levels of the protein may play a role in the pathogenesis of sporadic cases of the disease.

Association of an extended haplotype in the tau gene with progressive supranuclear palsy

We describe two extended haplotypes that cover the human tau gene. In a total of approximately 200 unrelated caucasian individuals there is complete disequilibrium between polymorphisms which span the gene (which covers approximately 100 kb of DNA). This suggests that the establishment of the two haplotypes was an ancient event and either that recombination is suppressed in this region, or that recombinant genes are selected against. Furthermore, we show that the more common haplotype (H1) is significantly over-represented in patients with progressive supranuclear palsy (PSP), extending earlier reports of an association between an intronic dinucleotide polymorphism and PSP.

Major depression, heart rate, and plasma norepinephrine in patients with coronary heart disease

BACKGROUND

Although it is now well established that psychiatric depression is associated with adverse outcomes in patients with coronary heart disease (CHD), the mechanism underlying this association is unclear. Elevated heart rate (HR) and plasma norepinephrine (NE), possibly reflecting altered autonomic nervous system activity, have been documented in medically well depressed psychiatric patients, and this pattern is associated with increased risk for cardiac events in patients with CHD. The purpose of this study was to determine whether autonomic nervous system activity is altered in depressed CHD patients.

METHODS

HR, plasma NE, and blood pressure (BP) were measured in 50 depressed and 39 medically comparable nondepressed CHD patients at rest and during orthostatic challenge.

RESULTS

Resting HR (p = .005), and the change from resting HR at 2, 5, and 10 min after standing (p = .02, .004, and .02, respectively), were significantly higher in the depressed than in the nondepressed patients. There were no differences between the groups in NE or in BP at rest, or in standing minus resting change scores at any time during orthostatic challenge (p < .05).

CONCLUSIONS

Depression is associated with altered autonomic activity in patients with CHD, as reflected by elevated resting HR and an exaggerated HR response to orthostatic challenge. Previously reported differences in NE levels between depressed and nondepressed patients were not replicated.

Low frequency of pathogenic mutations in the ubiquitin carboxy-terminal hydrolase gene in familial Parkinson's disease

A coding substitution (I93M) in the ubiquitin carboxy-terminal L1 (UCH-L1) gene has recently been identified in a German family with Parkinson's disease. We have sequenced the entire coding region of the gene in 11 families who have a pattern of disease consistent with autosomal dominant inheritance. We found a polymorphism (S18Y) in exon 3, two polymorphisms in the 5' non-coding region, upstream of the transcription start, and an insertion/deletion polymorphism in intron 4. The S18Y allele is present on approximately 20% of chromosomes in a Caucasian population. These changes are, therefore, unlikely to be pathogenic. We conclude that the I93M variant must either be a rare cause of disease or a harmless substitution whose occurrence in the family reflects a chance co-occurrence.

Apolipoprotein E genotype does not affect the age of onset of dementia in families with defined tau mutations

We have assessed whether apolipoprotein E (ApoE) genotype influences the age of onset of dementia in a series of families with frontal temporal dementia with defined mutations in the tau gene. In contrast to the situation in Alzheimer's disease (AD), we could find no evidence that the age of onset of disease was influenced by the ApoE genotype.

No pathogenic mutations in the persyn gene in Parkinson's disease

The persyn (gamma-synuclein) gene is highly homologous to the alpha-synuclein gene and is highly expressed in the nervous system. It is therefore, an excellent candidate gene for Parkinson's disease. However, we have sequenced the gene in a large number of families with parkinsonism and failed to find pathogenic mutations.

Vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor generates potent antitumor immunity in patients with metastatic melanoma

We conducted a Phase I clinical trial investigating the biologic activity of vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor in patients with metastatic melanoma. Immunization sites were intensely infiltrated with T lymphocytes, dendritic cells, macrophages, and eosinophils in all 21 evaluable patients. Although metastatic lesions resected before vaccination were minimally infiltrated with cells of the immune system in all patients, metastatic lesions resected after vaccination were densely infiltrated with T lymphocytes and plasma cells and showed extensive tumor destruction (at least 80%), fibrosis, and edema in 11 of 16 patients examined. Antimelanoma cytotoxic T cell and antibody responses were associated with tumor destruction. These results demonstrate that vaccination with irradiated autologous melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor stimulates potent antitumor immunity in humans with metastatic melanoma.

CADASIL in a North American family: clinical, pathologic, and radiologic findings

OBJECTIVE

To expand the reported phenotypic range of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

BACKGROUND

Despite numerous patient reports, our knowledge of the phenotypic range of CADASIL remains incomplete.

METHOD

We performed clinical, pathologic, and radiologic examinations on members of a family with CADASIL.

RESULTS

The proband is a 61-year-old man with a history of migraine and depression who has experienced multiple subcortical infarctions resulting in a stepwise decline. Neuropsychological testing documented a dementia syndrome with frontal lobe features and neurologic examination noted a left hemiparesis and a right-sided palmomental reflex. Brain biopsy with light microscopy revealed a nonatherosclerotic small-vessel angiopathy with periodic acid-Schiff positive granular changes in the media and white matter gliosis, with unremarkable cortex. Genetic testing confirmed a Notch3 mutation. The proband's first cousin has a history of depression, one seizure possibly resulting from an acute stroke, and a learning disorder. Neuropsychological testing demonstrated deficits in executive function and neurologic examination noted persistent extraneous adventitial movements, poor coordination, and primitive reflexes. Skin biopsy with electron microscopy demonstrated granular osmiophilic material within the basement membrane of vascular smooth muscle cells, which is considered to be pathognomonic of CADASIL. The proband's older son and younger son have histories of migraine and depression, respectively, and both also had learning disorders. MRI revealed diffuse white matter disease extending into the temporal lobes, and lacunar infarctions in these four nonhypertensive patients. Other family members have experienced migraine, recurrent stroke, dementia, and depression.

CONCLUSIONS

CADASIL is a genetic basis for vascular dementia that may be manifest earlier in life than previously reported.

Association of missense and 5'-splice-site mutations in tau with the inherited dementia FTDP-17

Thirteen families have been described with an autosomal dominantly inherited dementia named frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), historically termed Pick's disease. Most FTDP-17 cases show neuronal and/or glial inclusions that stain positively with antibodies raised against the microtubule-associated protein Tau, although the Tau pathology varies considerably in both its quantity (or severity) and characteristics. Previous studies have mapped the FTDP-17 locus to a 2-centimorgan region on chromosome 17q21.11; the tau gene also lies within this region. We have now sequenced tau in FTDP-17 families and identified three missense mutations (G272V, P301L and R406W) and three mutations in the 5' splice site of exon 10. The splice-site mutations all destabilize a potential stem-loop structure which is probably involved in regulating the alternative splicing of exon10. This causes more frequent usage of the 5' splice site and an increased proportion of tau transcripts that include exon 10. The increase in exon 10+ messenger RNA will increase the proportion of Tau containing four microtubule-binding repeats, which is consistent with the neuropathology described in several families with FTDP-17.

Synthetic matrix metalloproteinase inhibitor, BB-94, inhibits the invasion of neoplastic human prostate cells in a mouse model

BACKGROUND

It has been suggested that increased metalloproteinase activity is a critical event in neoplastic progression leading to the initiation of local invasion and ultimately to the dissemination of neoplastic cells. This has led to an interest in testing the ability of metalloproteinase inhibitors to prevent the progression of carcinoma in situ into invasive and, therefore, more malignant tumors. One such agent is the synthetic matrix metalloproteinase inhibitor, BB-94.

METHODS

The effect of BB-94 on the intrinsic invasive potential of matrilysin-transfected Du-145 cells was evaluated by an in vitro invasion assay. In addition a diaphragm invasion model, which provides an easily oriented structure in which the earliest penetration of the basal lamina can be observed, was used to investigate the effect of BB-94 on the invasion and growth of tumors formed by these cells when injected into S.C.I.D. mice.

RESULTS

The synthetic matrix metalloproteinase inhibitor, BB-94, was shown to effectively inhibit the invasion of matrigel and murine diaphragm.

CONCLUSIONS

Metalloproteinase inhibitors, such as BB-94, that are able to limit tumor growth, and local invasion, may decrease the invasion of invasive carcinomas.

Hereditary dysphasic disinhibition dementia: a frontotemporal dementia linked to 17q21-22

OBJECTIVE

The clinical and pathologic features of hereditary dysphasic disinhibition dementia (HDDD) are described to determine whether it is a variant of known dementias.

BACKGROUND

Several dementing disorders have clinical and pathologic similarities with AD, Pick's disease, and the "nonspecific" dementias. A detailed description of clinical and pathologic presentation will aid classification, but ultimately the discovery of causative gene(s) will define these disorders.

METHODS

The authors performed a clinical assessment: gross and microscopic pathologic evaluation of brain tissue, genetic linkage studies, and sequence analyses.

RESULTS

HDDD is an autosomal-dominant frontotemporal dementia with many similarities to Pick's disease. Salient clinical features are global dementia with disproportionate dysphasia and "frontotemporal" symptoms. A linkage between HDDD and 17q21-22 was shown, with a maximum lod score of 3.68 at zero recombination.

CONCLUSIONS

Several dementias have been linked to the same region and have been termed frontotemporal dementia with parkinsonism linked to chromosome 17. These disorders may represent phenotypic variants arising from mutations within a common gene.