Breast-to-brain metastasis is exacerbated with chemotherapy through blood-cerebrospinal fluid barrier and induces Alzheimer's-like pathology

Control of breast-to-brain metastasis remains an urgent unmet clinical need. While chemotherapies are essential in reducing systemic tumor burden, they have been shown to promote non-brain metastatic invasiveness and drug-driven neurocognitive deficits through the formation of neurofibrillary tangles (NFT), independently. Now, in this study, we investigated the effect of chemotherapy on brain metastatic progression and promoting tumor-mediated NFT. Results show chemotherapies increase brain-barrier permeability and facilitate enhanced tumor infiltration, particularly through the blood-cerebrospinal fluid barrier (BCSFB). This is attributed to increased expression of matrix metalloproteinase 9 (MMP9) which, in turn, mediates loss of Claudin-6 within the choroid plexus cells of the BCSFB. Importantly, increased MMP9 activity in the choroid epithelium following chemotherapy results in cleavage and release of Tau from breast cancer cells. This cleaved Tau forms tumor-derived NFT that further destabilize the BCSFB. Our results underline for the first time the importance of the BCSFB as a vulnerable point of entry for brain-seeking tumor cells post-chemotherapy and indicate that tumor cells themselves contribute to Alzheimer's-like tauopathy.

Burden of neuroinfectious diseases on the neurology service in a tertiary care center

BACKGROUND

Neurologic infections have the potential to cause death and suffering. These disorders often go unrecognized or are misdiagnosed. There has yet not been a census of neurologic infections conducted in a hospital setting. We aimed to determine the burden of neurologic infections on the neurology service in a tertiary care center and identify challenges in the diagnosis and treatment of these infections.

METHODS

We reviewed retrospectively all inpatients diagnosed with any neuroinfectious disease evaluated at Johns Hopkins Medical Institutions between October 2004 and December 2005. We recorded information on hospital admission, clinical features, microbiologic analysis, neuroimaging, EEG, pathology, treatment, and outcome.

RESULTS

A total of 116 of 4,225 patients admitted to or consulted on by the neurology service were identified. Eighty percent of patients were aged between 18 and 65 years. Fifty-two patients were immunocompromised, of which 28 patients had HIV infection. Overall, 86 microbiologic agents were identified in 80 patients. The commonest causes were viral, followed by bacterial and fungal infections. However, 31% of patients remained without an identifiable microbiologic etiology. Hospitalization periods were long, with 43% of patients staying beyond 2 weeks. There was significant morbidity: 28% of patients required rehabilitation or long-term care, and 12% died.

CONCLUSIONS

Neurologic infections have a major socioeconomic impact because they result in prolonged hospitalizations, expensive diagnostic tests and treatments, and long-term debilitation or death in young patients. Though potentially curable conditions, the burden of undiagnosed infections remains high.

Association between sleeping hours, working hours and obesity in Hong Kong Chinese: the 'better health for better Hong Kong' health promotion campaign

OBJECTIVE

To study the inter-relationships between sleeping hours, working hours and obesity in subjects from a working population.

RESEARCH DESIGN

A cross-sectional observation study under the 'Better Health for Better Hong Kong' Campaign, which is a territory-wide health awareness and promotion program.

SUBJECTS

4793 subjects (2353 (49.1%) men and 2440 (50.9%) women). Their mean age (+/-s.d.) was 42.4+/-8.9 years (range 17-83 years, median 43.0 years). Subjects were randomly selected using computer-generated codes in accordance to the distribution of occupational groups in Hong Kong.

RESULTS

The mean daily sleeping time was 7.06+/-1.03 h (women vs men: 7.14+/-1.08 h vs 6.98+/-0.96 h, P<0.001). Increasing body mass index (BMI) was associated with reducing number of sleeping hours and increasing number of working hours reaching significance in the whole group as well as among male subjects. Those with short sleeping hour (6 h or less) and long working hours (>9 h) had the highest BMI and waist in both men and women. Based on multiple regression analysis with age, smoking, alcohol drinking, systolic and diastolic blood pressure, mean daily sleeping hours and working hours as independent variables, BMI was independently associated with age, systolic and diastolic blood pressure in women, whereas waist was associated with age, smoking and blood pressure. In men, blood pressure, sleeping hours and working hours were independently associated with BMI, whereas waist was independently associated with age, smoking, blood pressure, sleeping hours and working hours in men.

CONCLUSION

Obesity is associated with reduced sleeping hours and long working hours in men among Hong Kong Chinese working population. Further studies are needed to investigate the underlying mechanisms of this relationship and its potential implication on prevention and management of obesity.

Abnormal p38 mitogen-activated protein kinase signalling in human and experimental diabetic nephropathy

AIMS/HYPOTHESIS

Inflammation and fibrosis are pathological mechanisms that are partially regulated by cell signalling through the p38 mitogen-activated protein kinase (MAPK) pathway. Elements of the diabetic milieu such as high glucose and advanced glycation end-products induce activation of this pathway in renal cells. Therefore, we examined whether p38 MAPK signalling is associated with the development of human and experimental diabetic nephropathy.

METHODS

Immunostaining identified phosphorylated (active) p38 MAPK in human biopsies with no abnormality ( n=6) and with Type 2 diabetic nephropathy ( n=12). Changes in kidney levels of phosphorylated p38 were assessed by immunostaining and western blotting in mice with streptozotocin-induced Type 1 diabetes that had been killed after 0.5, 2, 3, 4 and 8 months, and in Type 2 diabetic db/db mice at 2, 4, 6 and 8 months of age.

RESULTS

Phosphorylated p38 was detected in some intrinsic cells in normal human kidney, including podocytes, cortical tubules and occasional interstitial cells. Greater numbers of these phosphorylated p38+ cells were observed in diabetic patients, and phosphorylated p38 was identified in accumulating interstitial macrophages and myofibroblasts. A similar pattern of p38 activation was observed in both mouse models of diabetes. In mice, kidney levels of phosphorylated p38 increased (2-6 fold) following the onset of Type 1 and Type 2 diabetes. In both mouse models, interstitial phosphorylated p38+ cells were associated with hyperglycaemia, increased HbA(1)c levels and albuminuria. Further assessment of streptozotocin-induced diabetic nephropathy showed that interstitial phosphorylated p38+ cells correlated with interstitial fibrosis (myofibroblasts, collagen).

CONCLUSIONS/INTERPRETATION

Increased p38 MAPK signalling is a feature of human and experimental diabetic nephropathy. Time course studies in mouse models suggest that phosphorylation of p38 plays a pathological role, particularly in the development of interstitial fibrosis.

The polymorphisms of HLA-DR and TNF B loci in northern Chinese Han nationality and susceptibility to systemic lupus erythematosus

With the aid of methods of polymerase chain reaction/sequence specific primers (PCR/SSP) and polymerase chain reaction-restriction fragment length polymorphism (PCR/RFLP), the allelic polymorphism of HLA-DR and TNFB loci and susceptibility to systemic lupus erythematosus (SLE) in northern Chinese Han nationality were studied. The genetic analysis of 51 patients with SLE and 106 healthy controls indicated that frequencies of DR2 and DR3 alleles were significantly increased in SLE patients (P < 0.05 and < 0.005, relative risks of 1.77 and 4.01 respectively), which represent candidate susceptible genes or useful marker for SLE. The frequency of DR5 was found to decrease in SLE patients compared with control population (P < 0.025, relative risk = 0.38). It might be an antagonistic or protective allele or a marker for such allele. Analysis of 51 patients with SLE and 80 healthy control also revealed that the frequency of TNFB*2 allele was significantly increased (P < 0.05, RR = 1.70). Therefore TNFB*2 gene may also be a susceptibility gene or a marker gene for SLE in northern Chinese Han nationality. It was also investigated the association between HLA-DR, TNF B alleles and Patient plasmic SC5b-9 levels, auto-antibodies (anti-SSA, SSB, Sm, RNP, ds DNA and ANA) and SLE complications (SLE nephritis, SLE pneumonitis and SLE encephalopathy), no relationship was found.

Hierarchical graph visualization using neural networks

An algorithm based on a Hopfield network for solving the hierarchical graph visualization problem is presented. It simultaneously minimizes the number of crossings and total path length to produce two-dimensional drawings easily interpreted by human observers. Traditional heuristics often follow a more local optimization approach where "readability" criteria are sequentially applied, such as applying the barycentric heuristic followed by the priority layout heuristic. As a result of the more global approach, the neural network achieved comparable crossing minimization to the barycentric heuristic while simultaneously reducing total path length up to 50% over the priority layout heuristic for the benchmarks tested.

Lower esophageal contractility predicts movement during skin incision in patients anesthetized with halothane, but not with nitrous oxide and alfentanil

The frequency of spontaneous lower esophageal contractions (SLEC) has been proposed as one measure of anesthetic depth. The authors tested the hypothesis that SLEC frequency can predict movement in response to skin incision during halothane or nitrous oxide/alfentanil anesthesia. The incidence of movement during skin incision was compared with the frequency of spontaneous lower esophageal contractions in 20 healthy patients anesthetized with halothane. Esophageal contractility was determined using the Lectron 302, which senses the pressure in a water-filled balloon positioned in the distal esophagus. Absence of SLEC in the 6 min preceding incision correlated with no movement, with one exception (n = 9). All but one patient having greater than or equal to 2 SLEC in the 6 min preceding skin incision moved (n = 8) (P less than 0.01). Sixteen additional patients anesthetized with nitrous oxide (70%) and alfentanil demonstrated no correlation between SLEC frequency and movement. These data suggest that the frequency of spontaneous lower esophageal contractions, and its ability to predict movement, depends on anesthetic type.

Seizures associated with spontaneous subarachnoid hemorrhage

We analysed the charts of 131 consecutive cases of spontaneous subarachnoid hemorrhage--without arteriovenous malformations--for seizures. Convulsions occurred in 31 patients (24%) and most often within 24 hours of bleeding. Motor manifestations of partial seizures were of no lateralizing value to aneurysm site. Early mortality, rebleeding and intracerebral hematoma were similar in both seizure and non-seizure groups. Late seizures were infrequent in survivors who had suffered seizures in the acute stage--thus questioning the necessity for routine, long term prophylactic anticonvulsants in these patients.

Chemical and enzymatic biotin-labeling of oligodeoxyribonucleotides

Biotin has been converted to 2-(biotinylamido)ethanol and condensed to phosphorylated oligonucleotides in a solid phase synthesis. The 5'-biotinylated oligonucleotides were enzymatically coupled to other DNA fragments by T4 DNA ligase or T4 RNA ligase. The hybridization properties of such biotin-labeled oligonucleotide probes were studied.

Selective 2'-benzoylation at the cis 2',3'-diols of protected ribonucleosides. New solid phase synthesis of RNA and DNA-RNA mixtures

5'-0-(Dimethoxytrityl)-2'-0-(benzoyl or 3,4,5-trimethoxybenzoyl)-base protected ribonucleosides have been prepared by selective benzoylation of the 2'-hydroxyl group. The isomerization of the 2'-benzoates to the 3'-benzoates was studied. The protected ribonucleosides have been converted to either methylphosphochloridites or methylphosphoamidites and used to synthesize oligoribonucleotides on silica gel solid support. The synthetic RNA were deprotected and isolated using conditions that minimize internucleotide cleavage. The use of 2'-benzoates as protecting groups for ribonucleosides has made it possible to easily prepare and isolate mixtures of DNA and RNA.

Typing of herpes simplex virus with type-specific human immunoglobulin M in an indirect immunofluorescence assay

Sera from nine individuals with suspected primary herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) infection were screened to identify those containing HSV type-specific immunoglobulin M (IgM). Selected sera were then utilized in an IgM-specific indirect immunofluorescent-antibody HSV-typing assay (patent pending). To evaluate the procedure, 29 HSV isolates were grown in cultures of continuous human amnion cells, fixed, and used as substrates for indirect immunofluorescence. Determination of virus type was based on intensity of fluorescence of the substrate with HSV-1- and HSV-2-specific antisera after staining with fluorescein-conjugated anti-human IgM. Typing of the isolates by restriction endonuclease digestion showed that of 29, 18 were HSV-2 and 11 were HSV-1. Results by IgM-specific indirect immunofluorescent-antibody assay were identical to those by restriction endonuclease digestion for 27 of the isolates; 2 isolates failed to replicate adequately in the test cells. The IgM-specific indirect immunofluorescent-antibody procedure appears to be a simple, rapid, and accurate technique which could be of use to clinical virology laboratories.

Synthesis of oligodeoxyribonucleotides on silica gel support

A rapid solid phase method of oligonucleotide synthesis based on monomeric protected nucleosides has been developed.

Specific detection of primary amines in the effluent of a gas-chromatographic column by on-line measurement of fluorescence

Compounds with primary amino groups react with o-phthalaldehyde in solution to yield highly fluorescent products. This reaction is now in wide use for detecting amino acids and amines in liquid-chromatography effluents. We report here a method for using o-phthalaldehyde to detect primary amines in the effluent of a gas-liquid-chromatographic column. The effluent gas, nominally 20 mL/min, is delivered to a scrubber consisting of a small-bore, simulated capillary chromatographic column that is simultaneously supplied with 1 mL/min of the reagent solution. The liquid effluent of the scrubber, separated from the gas, is drawn through the flow cell of a fluorometer. Short-chain amines and ammonia were quantitatively scrubbed. The response of the fluorometer was directly proportional to the number of nanomoles injected into the column. Less than a nanomole of amine was detectable. Comparison of results with those from a hydrogen flame-ionization detector showed minimal additional peak broadening or compromise of resolution. These results demonstrate the feasibility of using highly specific, as well as sensitive, liquid-chromatographic detection methods for gas-liquid chromatography.

Specific detection of primary amines in the effluent of a gas-chromatographic column by on-line measurement of fluorescence

Compounds with primary amino groups react with o-phthalaldehyde in solution to yield highly fluorescent products. This reaction is now in wide use for detecting amino acids and amines in liquid-chromatography effluents. We report here a method for using o-phthalaldehyde to detect primary amines in the effluent of a gas-liquid-chromatographic column. The effluent gas, nominally 20 mL/min, is delivered to a scrubber consisting of a small-bore, simulated capillary chromatographic column that is simultaneously supplied with 1 mL/min of the reagent solution. The liquid effluent of the scrubber, separated from the gas, is drawn through the flow cell of a fluorometer. Short-chain amines and ammonia were quantitatively scrubbed. The response of the fluorometer was directly proportional to the number of nanomoles injected into the column. Less than a nanomole of amine was detectable. Comparison of results with those from a hydrogen flame-ionization detector showed minimal additional peak broadening or compromise of resolution. These results demonstrate the feasibility of using highly specific, as well as sensitive, liquid-chromatographic detection methods for gas-liquid chromatography.