Equation of state and critical point behavior of hard-core double-Yukawa fluids

A theoretical study on the equation of state and the critical point behavior of hard-core double-Yukawa fluids is presented. Thermodynamic perturbation theory, restricted to first order in the inverse temperature and having the hard-sphere fluid as the reference system, is used to derive a relatively simple analytical equation of state of hard-core multi-Yukawa fluids. Using such an equation of state, the compressibility factor and phase behavior of six representative hard-core double-Yukawa fluids are examined and compared with available simulation results. The effect of varying the parameters of the hard-core double-Yukawa intermolecular potential on the location of the critical point is also analyzed using different perspectives. The relevance of this analysis for fluids whose molecules interact with realistic potentials is also pointed out.

Treatment-related morbidity in atypical teratoid/rhabdoid tumor: multifocal necrotizing leukoencephalopathy

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive malignant brain tumor that, since it was first identified, has been treated with aggressive treatment regimens, e.g. high-dose chemotherapy with stem cell rescue and early radiotherapy. We reviewed our experience because of concerns with respect to treatment-related toxicity in our patients.

METHODS

Seven patients with a median age at presentation of 18 months were diagnosed with AT/RT between 1996 and 2006. Tumor location was supratentorial in 2 patients, in the posterior fossa in 4 and spinal in 1. Gross total resection was performed in 1 patient, subtotal resection in 5 and biopsy only in 1. Adjuvant treatment consisted of chemotherapy and radiotherapy in 5 patients.

RESULTS

Median progression-free survival was 4 months, and median overall survival was 7 months. Two children are alive at 44 and 102 months. Significant surgical and chemotherapy-related morbidity was seen. Biopsy-proven multifocal necrotizing leukoencephalopathy (MNL) was seen in one patient who is alive 44 months after diagnosis. Another patient who was thought to have recurrent tumor in the brainstem 9 months after diagnosis had imaging findings compatible with MNL.

CONCLUSION

Although improving results are reported for AT/RT using intensive treatment regimens, treatment-related morbidity is considerable in this young patient population.

Six-Minute Walk Test demonstrates motor fatigue in spinal muscular atrophy

BACKGROUND

In spinal muscular atrophy (SMA), weakness, decreased endurance, and fatigue limit mobility. Scales have been developed to measure function across the wide spectrum of disease severity. However, these scales typically are observer dependent, and scores are based on sums across Likert-scaled items. The Six-Minute Walk Test (6MWT) is an objective, easily administered, and standardized evaluation of functional exercise capacity that has been proven reliable in other neurologic disorders and in children.

METHODS

To study the performance of the 6MWT in SMA, 18 ambulatory participants were evaluated in a cross-sectional study. Clinical measures were 6MWT, 10-m walk/run, Hammersmith Functional Motor Scale-Expanded (HFMSE), forced vital capacity, and handheld dynamometry. Associations between the 6MWT total distance and other outcomes were analyzed using Spearman correlation coefficients. A paired t test was used to compare the mean distance walked in the first and sixth minutes.

RESULTS

The 6MWT was associated with the HFMSE score (r = 0.83, p < 0.0001), 10-m walk/run (r = -0.87, p < 0.0001), and knee flexor strength (r = 0.62, p = 0.01). Gait velocity decreased during successive minutes in nearly all participants. The average first minute distance (57.5 m) was significantly more than the sixth minute distance (48 m) (p = 0.0003).

CONCLUSION

The Six-Minute Walk Test (6MWT) can be safely performed in ambulatory patients with spinal muscular atrophy (SMA), correlates with established outcome measures, and is sensitive to fatigue-related changes. The 6MWT is a promising candidate outcome measure for clinical trials in ambulatory subjects with SMA.

[Characteristics of metastatic prostate cancer occurring in patients under 50 years of age]

OBJECTIVE

To identify the clinical features, diagnostic approach, and treatment of metastatic prostate cancer in young adult patients.

METHODS

A retrospective review was made of the clinical histories of patients under 50 years of age diagnosed with prostate cancer at the urology department of the National Institute for Neoplastic Diseases from 1952 to 2005. Demographic characteristics and data on history, symptoms, diagnostic procedures, treatment, and disease course were collected. Data were statistically analyzed and compared to information obtained from a literature search.

RESULTS

There were 69 patients aged less than 50 years who had been diagnosed with prostate cancer, 60% of whom had metastatic tumors. Mean patient age was 45.5 years, with a lower range of 29. All patients reported bone pain, associated to other signs and symptoms such as spinal cord compression (19.5%), lower limb edema (17%), peripheral adenopathies (36.5%), and abdominal tumor (2.4%). All patients had bone metastases, of which 14.6% were in solid organs (lung and liver), 48.7% in retroperitoneum, and 7.3% in mediastinum. Initially, three patients were diagnosed a lymphoproliferative syndrome, one patient a retroperitoneal tumor of unknown etiology, and four patients a metastasis from an unknown primary tumor. Mean prostate-specific antigen (PSA) level was 795 ng/mL (3-6500). All pathologies were reported as poorly differentiated or undifferentiated. Mean survival was 16.1 months (1-84), and all patients died due to disease progression.

CONCLUSIONS

Advanced prostate cancer is an uncommon condition in young adults. Its clinical presentation is atypical, as metastases may mimic other diseases. The course of disease is indolent, and prognosis is poor. In patients with risk factors, PSA testing should be started before 50 years of age.

Rehabilitation in Social Cognition for Bipolar Patients: A State of the Art

Deficits in social cognition have been reported in euthymic bipolar patients. Thus, these deficits could be determining the disability observed in these patients for achieving the functionality expected at work or in sociability. In this way, there is a need for specific programs of rehabilitation in social cognition in bipolar disorder. Unfortunately, there is a paucity of programmes designed for improving social cognition in bipolar patients. A review of these programmes will be presented.

Expression of SEAP (secreted alkaline phosphatase) by baculovirus mediated transduction of HEK 293 cells in a hollow fiber bioreactor system

A BacMam baculovirus was designed in our laboratory to express the reporter protein secreted alkaline phosphatase (SEAP) driven by the immediate early promoter of human cytomegalovirus promoter (CMV). In vitro tests have been carried out using this recombinant baculovirus to study the secreted protein in two cell lines and under various culture conditions. The transductions were carried out on two commonly used mammalian cell lines namely the human embryonic kidney (HEK 293A) and Chinese hamster ovary (CHO-K1). Initial studies clearly demonstrated that the transient expression of SEAP was at least 10-fold higher in the HEK 293 cells than the CHO cells under equivalent experimental conditions. Factorial design experiments were done to study the effect of different parameters such as cell density, MOI, and the histone deacetylase inhibitor, trichostatin A concentration. The multiplicity of infection (MOI) and the cell density were found to have the most impact on the process. The enhancer trichostatin A also showed some positive effect. The production of secreted protein in a batch reactor was studied using the Wave disposable bioreactor system. A semi-continuous perfusion process was developed to extend the period of gene expression in mammalian cells using a hollow fiber bioreactor system (HFBR). The growth of cells and viability in both systems was monitored by offline analyses of metabolites. The expression of recombinant protein could be maintained over an extended period of time up to 30 days in the HFBR.

Quantitative objective markers for upper and lower motor neuron dysfunction in ALS

OBJECTIVE

To investigate the value of objective biomarkers for upper (UMN) and lower (LMN) motor neuron involvement in ALS.

METHODS

We prospectively studied 64 patients with ALS and its subsets using clinical measures, proton MR spectroscopic imaging ((1)H MRSI), diffusion tensor imaging, transcranial magnetic stimulation, and the motor unit number estimation (MUNE) at baseline and every 3 months for 15 months and compared them with control subjects.

RESULTS

(1)H MRSI measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration were markedly reduced in ALS (p = 0.009) and all UMN syndromes combined (ALS, familial ALS [fALS], and primary lateral sclerosis; p = 0.03) vs control values. Central motor conduction time to the tibialis anterior was prolonged in ALS (p < 0.0005) and combined UMN syndromes (p = 0.001). MUNE was lower in ALS (p < 0.0005) and all LMN syndromes combined (ALS, fALS, and progressive muscular atrophy; p = 0.001) vs controls. All objective markers correlated well with the ALS Functional Rating Scale-Revised, finger and foot tapping, and strength testing, suggesting these markers related to disease activity. Regarding changes over time, MUNE changed rapidly, whereas neuroimaging markers changed more slowly and did not significantly differ from baseline.

CONCLUSIONS

(1)H MR spectroscopic imaging measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration and ratio of NAA to creatine, central motor conduction time to the tibialis anterior, and motor unit number estimation significantly differed between ALS, its subsets, and control subjects, suggesting they have potential to provide insight into the pathobiology of these disorders.

Development and evaluation of a self-administered version of the ALSFRS-R

We evaluated the reliability and sensitivity to change over time of a newly developed self-administered version of the ALS functional rating scale-revised (ALSFRS-R) in 60 consecutive patients from an ALS clinic. The self-administered ALSFRS-R showed excellent reliability (intraclass correlation = 0.93, 95% CI: 088 to 0.96) and similar sensitivity to change over time vs the standard evaluator-administered ALSFRS-R.

Fatal pulmonary embolism and fatal bleeding in cancer patients with venous thromboembolism: findings from the RIETE registry

OBJECTIVES

To examine the clinical characteristics and outcomes of cancer patients with venous thromboembolism (VTE) in order to identify factors that place these patients at an increased risk for fatal pulmonary embolism (PE) or fatal bleeding.

PATIENTS AND METHODS

Registro Informatizado de la Enfermedad Trombo Embólica (RIETE) is a prospective registry of consecutive patients with symptomatic, objectively confirmed, acute VTE.

RESULTS

Up to January 2006, a total of 14 391 patients with symptomatic acute VTE were enrolled in RIETE, of whom 2945 (20%) had cancer. During the 3-month follow-up period the frequency of fatal PE in cancer patients was 2.6%, and that of fatal bleeding 1.0%. These frequencies were significantly higher than in VTE patients without cancer (1.4% and 0.3%, respectively). In patients with cancer, abnormal renal function, metastatic disease, recent major bleeding and recent immobility for >or= 4 days (42% of the 108 patients who died from PE or bleeding had recent immobility) were factors independently associated with an increased risk for both fatal PE and fatal bleeding. In addition, PE diagnosis on admission was an independent risk factor for fatal PE, while body weight < 60 kg was an independent risk factor for fatal bleeding.

CONCLUSIONS

Both fatal PE and fatal bleeding are more common in cancer patients with VTE than in those patients without cancer. In cancer patients, abnormal renal function, metastatic disease, recent major bleeding and recent immobility for >or= 4 days are associated with an increased risk for both fatal PE and fatal bleeding.