Alzheimer's disease and Down's syndrome: Treating two paths to dementia

Successful therapy of dementia, like any disease, depends upon understanding its pathogenesis. This review contrasts the dominant pathways to dementia which differ in Alzheimer's disease (AD) and in Down's syndrome (DS). Impaired clearance of neurotoxic amyloid beta peptides (Abeta) leads to dementia in AD. In DS over-production of Abeta plays the dominant role in the development of dementia. It follows, therefore, that the therapy of AD and DS should reflect a different balance between the dominant agent that inhibits the synthesis of Abeta in the brain in AD and increase the clearance of Abeta from the cerebrospinal DS.     

Abrupt propranolol withdrawal in angina pectoris: effects on platelet aggregation and exercise tolerance.

Data collected before the initial reports of myocardial infarction following sudden withdrawal of propranolol are presented here to evaluate possible mechanisms for this phenomenon. Twenty patients with angina pectoris were randomized into placebo and propranolol (160 mg./day) treated groups and followed for 50 weeks at which time treatment was abruptly discontinued. Measurements of exercise tolerance, the product of heart rate and blood pressure at exercise end-point (HR × BP), and platelet aggregation thresholds in response to ADP and epinephrine were made before, during, and after treatment. Prior to propranolol, mean total work performance was 765 ± 125 k.p.m., HR × BP (heart rate-blood pressure product) was 16,800 ± 1,535. Mean platelet aggregation threshold with ADP was 1.32 μM¹; with epinephrine 1.26 μM¹. Patients treated with propranolol demonstrated significant improvement in exercise performance (1,790 ± 285 k.p.m., p < .01), reduction in HR × BP (12,000 ± 895, p < .01), and an elevation in platelet aggregation threshold; with ADP 3.43 μM¹ (p < .01); with epinephrine 12.9 μM¹ (p < .01). Following abrupt cessation of propranolol, exercise tolerance and HR × BP fell below pretreatment levels (630 ± 117 k.p.m. and 15,500 ± 513, respectively). Similarly platelet aggregation threshold fell to 1.0 μM¹ with ADP and 0.57 μM¹ with epinephrine. In six patients platelets were significantly more hyperaggregable than prior to therapy. Anginal frequency increased in all, but no acute infarction was observed. Abrupt withdrawal of propranolol may be deleterious in patients, sometimes causing “rebound” platelet hyperaggregability associated with increasing anginal frequency and decreasing exercise tolerance.     

Lipoid nephrosis in Hodgkin's disease

Two cases of Hodgkin's disease presenting as the nephrotic syndrome are described. Evaluation of the renal biopsy specimens by light microscopy, electron microscopy and immuno-fluorescent antibody staining was most compatible with a lipoid nephrosis type of lesion. In both cases there was a prompt and prolonged remission of the nephrotic syndrome when the Hodgkin's disease was treated with radiation therapy.     

Age-dependent appearance of non-major histocompatibility complex-restricted helper T cells.

T cells which recognize antigen in association with self major histocompatibility complex (MHC) molecules are positively selected within the thymus. This results in skewing of the T-cell repertoire toward the recognition of antigenic peptides presented by self MHC molecules. While the thymus gland involutes at a relatively young age, bone marrow function and the size of the peripheral T-cell pool are maintained with age. We have investigated the MHC restriction of helper T-cell function for B-cell production of specific antibody in mice of different ages. Splenic helper T cells from 2- to 3-month old mice immunized with phosphocholine-keyhole limpet hemocyanin conjugate were MHC-restricted as defined by their capacity to induce phosphocholine-specific antibody synthesis by syngeneic but not by allogeneic B cells. In contrast, splenic T cells from immunized 18- to 20-month-old mice induced specific anti-phosphocholine antibodies by both syngeneic and allogeneic B cells. No evidence of polyclonal immunoglobulin synthesis was detected. The ability of T cells from old mice immunized with phosphocholine-keyhole limpet hemocyanin to induce phosphocholine-specific antibody synthesis by B cells from allogeneic mice was inhibited by T cells from immunized young mice. These findings suggest that non-MHC-restricted T-cell helper activity in old mice results from the loss of T cells, present in young mice, which suppress non-MHC-restricted helper cells.     

Major Perioperative Morbidity Does Not Affect Long-Term Survival in Patients Undergoing Esophagectomy for Cancer of the Esophagus or Gastroesophageal Junction

Introduction

The incidence of cancer of the esophagus/GE junction is dramatically increasing but continues to have a dismal prognosis. Esophagectomy provides the best opportunity for long-term cure but is hampered by increased rates of perioperative morbidity. We reviewed our large institutional experience to evaluate the impact of postoperative complications on the long-term survival of patients undergoing resection for curative intent.

Methods

We identified 237 patients who underwent esophagogastrectomy, with curative intent, for cancer between 1994 and 2008. Complications were graded using the previously published Clavien scale. Survival was calculated using Kaplan–Meier methodology and survival curves were compared using log-rank tests. Multivariate analysis was performed with continuous and categorical variables as predictors of survival, and examined with logistic regression and odds ratio confidence intervals.

Results

There were 12 (5 %) perioperative deaths. The average age of all patients was 62 years, and the majority (82 %) was male. Complication grade did not significantly affect long-term survival, although patients with grade IV (serious) complications did have a decreased survival (p = 0.15). Predictors of survival showed that the minimally invasive type esophagectomy (p = 0.0004) and pathologic stage (p = 0.0007) were determining factors. There was a significant difference in overall survival among patients who experienced pneumonia (p = 0.00016) and respiratory complications (p = 0.0004), but this was not significant on multivariate analysis.

Conclusions

In this single-institution series, we found that major perioperative morbidity did not have a negative impact on long-term survival which is different than previous series. The impact of tumor characteristics at time of resection on long-term survival is of most importance.     

Response to therapy in IgG myeloma patients excreting lambda or kappa light chains: CALGB experience.

Sixty-eight previously untreated patients with IgG myeloma who were entered into five protocols of Cancer and Leukemia Group B (CALGB) were studied in order to determine the possible influence of excretion of kappa versus lambda urinary light chains on responses to treatment and survival. All patients in these protocols were included if the serum and urine protein abnormalities were confirmed by one of the two group reference laboratories. Pretreatment characteristics of the two groups of patients did not differ significantly. Of 44 patients with kappa Bence Jones proteinuria, 19 patients (43%) had good responses to treatment, whereas only 3 of 24 patients (13%) with lambda Bence Jones proteinuria had good responses (p = 0.02). Survival for the patients excreting kappa light chains was significantly better than survival for patients excreting lambda chains (median survival 31 versus 12 mo, p = 0.02).     

Inhibition of Jun NH2-terminal kinases suppresses the growth of experimental head and neck squamous cell carcinoma.

PURPOSE: This study was carried out to investigate whether c-Jun NH2-terminal kinases (JNK) are potential targets for treating head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN: JNK activity was first evaluated in 20 paired samples of human HNSCC. The antitumor activity of SP600125, a reversible nonselective ATP-competitive inhibitor of JNKs, was then investigated both in an HNSCC xenograft model and in vitro using immunohistochemistry, immunoblotting, enzyme immunoassay, flow cytometry, and a Matrigel assay of capillary tube formation. Complementary studies were carried out using small interfering RNA to JNK1/2. RESULTS: JNK activity was increased in human HNSCC compared with normal-appearing epithelium. Treatment of mice bearing HNSCC xenografts with SP600125 resulted in >60% inhibition of tumor growth relative to vehicle-treated animals. Inhibition of tumor growth was associated with significant reductions in both cell proliferation and microvessel density. SP600125 inhibited tumor cell proliferation by causing delays in both the S and G2-M phases of the cell cycle. Inhibition of angiogenesis seemed to reflect effects on both tumor and endothelial cells. The JNK inhibitor suppressed the production of vascular endothelial growth factor and interleukin-8 by tumor cells and also inhibited endothelial cell proliferation and capillary tube formation. Reduced amounts and phosphorylation of epidermal growth factor receptor were found in tumor cells after treatment with SP600125. Small interfering RNA-mediated suppression of JNK1/2 led to reduced tumor cell proliferation and decreased levels of epidermal growth factor receptor, vascular endothelial growth factor, and interleukin-8. CONCLUSIONS: JNK activity is commonly increased in HNSCC. Our preclinical results provide a rationale for evaluating JNK inhibition as an approach to treating HNSCC.