Can noise reduction filters improve low-radiation-dose chest CT images? Pilot study

Effect of noise reduction filters on chest computed tomographic (CT) images acquired with 50% radiation dose reduction was evaluated. Two sets of images were acquired with multi-detector row CT at standard (220-280 mA) and 50% reduced (110-140 mA) tube current at the level of the carina. After postprocessing with six noise reduction filters, images were compared with baseline standard-dose images for noise, sharpness, and contrast in lungs, mediastinum, and chest wall. Quantitative image noise was measured in descending thoracic aorta. Modulation transfer functions were calculated from CT images of 50-microm wire. Noise reduction filters reduced image noise on low-radiation-dose chest CT images, with some compromise in image sharpness and contrast assessed qualitatively, and slightly altered modulation transfer function at higher spatial frequencies.     

Compressive preload improves the stability of anterior lumbar interbody fusion cage constructs

BACKGROUND: Insertion of an anterior lumbar interbody fusion cage has been shown to reduce motion in a human spine segment in all loading directions except extension. The "stand-alone" cages depend on compressive preload produced by anular pretensioning and muscle forces for initial stabilization. However, the effect that the in vivo compressive preload generated during activities of daily living has on the construct is not fully understood. This study tested the hypothesis that the ability of the cages to reduce the segmental motions in flexion and extension is significantly affected by the magnitude of the externally applied compressive preload. METHODS: Fourteen specimens from human lumbar spines were tested intact and after insertion of two threaded cylindrical cages at level L5-Sl. They were subjected to flexion and extension moments under progressively increasing magnitudes of externally applied compressive follower preload from 0 to 1200 N. The range of motion at level L5-S1 after cage insertion was compared with the value achieved in the intact specimens at each compressive preload magnitude. RESULTS: The cages significantly reduced the L5-S1 flexion motion at all preloads (p < 0.05). They decreased flexion motion by 29% to 43% of that of the intact specimens for low preloads (0 to 400 N) and by 69% to 79% of that of the intact specimens under preloads of 800 to 1200 N. In extension, in the absence of an externally applied preload, the cages permitted 24% more motion than the intact segment (p < 0.05). In contrast, they reduced the extension motion at preloads from 200 to 1200 N. Under preloads of 800 to 1200 N, the reduction in extension motion after cage placement was 42% to 48% of that of the intact segment (p < 0.05). The reduction of motion in both flexion and extension after cage placement was significantly greater at preloads of 800 to 1200 N compared with the motion reductions at preloads of < or =400 N (p < 0.05). CONCLUSIONS: In contrast to the observed extension instability under anular tension preload only, the two-cage construct exerted a stabilizing effect on the motion segment (a reduction in segmental motion) in flexion as well as extension under externally applied compressive preloads of physiologic magnitudes. The external compressive preload significantly affected the stabilization provided by the cages. The cages provided substantially more stabilization, both in flexion and in extension, at larger preloads than at smaller preloads. Clinical Relevance: The study suggests that the segment treated with an anterior lumbar interbody fusion cage is relatively less stable under conditions of low external compressive preload. The magnitude of preload required to achieve stabilization with stand-alone cages may be only partially achieved by anular pretensioning. Since the magnitude of the preload across the disc space due to muscle activity can vary with activities of daily living, supplemental stabilization of the cage construct may provide a more predictably stable environment for lumbar spine fusion.     

Epidemiology of cholera--a five year study

A total of 286 strains of Vibro Cholerae were isolated and tested over a period of five years. The strains were identified by standard methods and confirmed by slide agglutination tests with polyvalent, Ogawa and Inaba antisera. The non-agglutinating strains were tested with O-139 antisera. The maximum number of cases were found in the age group of 0-10 years. The number of females affected was more than the males. V. cholerae O-139 was isolated in the year 1998 and then again in 2000. V. cholerae serotype Inaba was found only in the year 1999. All of the other isolates belonged to the serotype Ogawa. The periodic shift between O1 and O-139 serogoups is reminiscent of the shifts from the Ogawa to the Inaba serotypes periodically witnessed among V. cholerae, possibly mediated by the immune pressure in the population.     

Phase II/pharmacodynamic trial of dose-intensive, weekly parenteral hydroxyurea and fluorouracil administered with interferon alfa-2a in patients with refractory malignancies of the gastrointestinal tract.

PURPOSE: Combined depletion of pyrimidine and purine DNA precursors has resulted in therapeutic synergism in vitro. The aims of the current study were to test this strategy in patients with refractory tumors and to assess its effects on selected nucleotide pools. PATIENTS AND METHODS: A single-institution phase II trial was initiated in patients with advanced carcinomas of the stomach and pancreas. Patients had measurable disease and had no prior chemotherapy except adjuvant fluorouracil (5FU) or gemcitabine. 5FU was administered by CADD + pump at 2.6 g/m(2) intravenously by 24-hour infusion on days 1, 8, 15, 22, 29, and 36. Parenteral hydroxyurea (HU) was administered at 4.3 g/m(2) as a 24-hour infusion concurrently with 5FU. Interferon alfa-2a (IFN-alpha2a) was administered at 9 million units subcutaneously on days 1, 3, and 5 each week. No drug was administered in weeks 7 and 8. Pharmacodynamic studies were performed to assess drug effects on levels of deoxyuridine triphosphate (dUTP) and thymidine triphosphate (TTP) pools in peripheral-blood mononuclear cells (PBMCs) before and 6 hours after treatment using a highly sensitive DNA polymerase assay. RESULTS: There were 53 patients enrolled onto the study (gastric carcinoma, 31; pancreatic carcinoma, 22). The median age was 61 years, with 22% of patients > or = 70 years old. The predominant grade 3 to 4 toxicities were leukopenia (49%), granulocytopenia (55%), and thrombocytopenia (22%). Severe diarrhea occurred in 12%, mucositis in 0%, and vomiting in 10% of patients. Patients > or = 70 years had no greater incidence of toxicities. Among the 30 assessable patients with gastric carcinoma, there were two (7%) complete responders and 11 (37%) partial responders (median duration, 7 months). Among the 21 assessable patients with pancreatic carcinoma, there was one responder. Median survival among all patients with gastric carcinoma was 10 months and 13 months for patients with pancreatic carcinoma. Twenty-three patients had samples studied for levels of dUTP and TTP. There was no change in the levels of TTP before and after treatment. Furthermore, dUTP was detected in only five of 28 samples after treatment with no increase in the dUTP/TTP ratio. CONCLUSION: Combination therapy with high-dose, weekly infusional HU and 5FU with IFN-alpha2a modulation was well-tolerated with activity in gastric cancer. Patients > or = 70 years tolerated therapy as well as younger patients. This was the first study to correlate levels of TTP and dUTP after treatment with clinical outcome. In PBMCs used as a surrogate tissue, HU abrogated the 5FU-induced increase in dUTP levels without reversing the overall efficacy of the regimen.     

Serum Mortalin Correlated with α-Synuclein as Serum Markers in Parkinson’s Disease: A Pilot Study

Mortalin, a mitochondrial chaperone, plays a crucial role in reducing toxicity of Lewy bodies. Earlier studies had reported that Mortalin level gets downregulated in astrocytes and other brain tissue samples in Parkinson’s disease (PD). This study aims to estimate the Mortalin concentration in serum and correlate with α-synuclein (α-Syn) in PD. The concentration of Mortalin and α-Syn in serum samples of 38 PD patients and 33 control group (CG) individuals was quantified by surface plasmon resonance. The receiver operating characteristic curves were plotted to develop it as blood-based protein marker. The expression of Mortalin in serum was validated by western blot. The Mortalin level was found to be declined in PD patients (1.98 ± 0.53 ng/µL) in comparison with CG individuals (3.13 ± 0.48 ng/µL), whereas α-Syn level was found to be elevated in PD patients (38.20 ± 4.22 ng/µL) than CG individuals (34.31 ± 3.23 ng/µL) in serum. The statistical analysis revealed the negative correlation between Mortalin and α-Syn. This preliminary study summarized that Mortalin plays a significant role in PD with negative correlation with α-Syn. This study provides a new paradigm for the development of Mortalin as a potent serum protein marker for diagnosis of PD.     

Genetic diversity of noroviruses and sapoviruses in children with acute sporadic gastroenteritis in New Delhi, India

BACKGROUND: Human caliciviruses (HuCVs) cause gastroenteritis throughout the world. Limited information is available on molecular epidemiology of caliciviruses from developing countries including India. OBJECTIVES: Standardization and evaluation of a two-step multiplex RT-PCR assay for HuCVs and characterization of strains. STUDY DESIGN: Two hundred and twenty-six stool samples were collected from children with acute gastroenteritis (AGE) over a one and half year to study the prevalence and diversity of HuCVs in children with AGE in New Delhi, India. A multiplex two-step RT-PCR using 3 sets of external and 4 sets of internal primers from the RdRp gene was standardized for detection of NoVs and SaVs. Molecular characterization of some HuCV strains was done by sequencing followed by phylogenetic analysis. RESULTS: Fifty-nine HuCVs strains were detected in 54 (24%) of the samples; 5 samples had mixed infections. Of these 59 HuCVs, 36 (61%) were norovirus (34 were GGII; 2 were GGI) and 23 (39%) were sapovirus (22 were GGI; 1 was GGII). Phylogenetic analysis of partial RdRp gene of 12 HuCV strains identified three genotypes (GGI/4, GGII/3 and a newly identified GIIb/Hilversum cluster) in NoVs and one genotype (GGI/1) in SaVs. CONCLUSION: This is one of the few reports from India on detection and characterization of HuCVs by multiplex RT-PCR assay. This assay can be a useful tool for epidemiological studies of HuCV infections.     

Involvement of α-MSH in the social isolation induced anxiety- and depression-like behaviors in rat

Although physical isolation of rats is known to cause anxiety- and depression-like symptoms, the underlying mechanisms are not fully understood. We have attempted to define the role of endogenous melanocortins (MC) in the manifestation of these symptoms. Weaning rats were socially isolated for 6 weeks and subjected to behavioral paradigms like elevated plus maze (EPM), social interaction, and forced swim test (FST). While socially isolated rats spent less time in social interaction, and showed significantly decreased activity in the open arms of the EPM, the immobility time in FST was significantly increased thus reflecting anxiety- and depression-like phenotypes. Intracerebroventricular injection of HS014 (5 or 10 nmol/rat), selective antagonist of MC4 receptors, attenuated these symptoms. This suggested the involvement of endogenous alpha-melanocyte stimulating hormone (α-MSH) in anxiety and depression. With a view to determining the neuroanatomical substrates in which the endogenous α-MSH may process the related information, profile of the peptide in paraventricular (PVN), arcuate (ARC), dorsomedial hypothalamic-dorsal (DMNd) and -ventral (DMNv) nuclei, and central nucleus of amygdala (CeA) was investigated with immunohistochemistry. While social isolation significantly reduced α-MSH-immunoreactivity profile in all these components, re-socialization of the socially isolated rats, over a period of 72 h, resulted in full recovery of the α-MSH-immunoreactivity profile; the symptoms of anxiety- and depression-like behaviors were also fully attenuated. We suggest that α-MSH in the PVN, ARC, DMNd, DMNv and CeA, acting via MC4 receptors, are involved in manifestation of affective disorders like anxiety and depression.     

Study of amplitude frequency spectra of the compound action potentials recorded from normal and M. leprae infected mice using Fourier series analysis

Compound action potentials recorded from normal and M. leprae infected mice sciatic nerves were analysed in frequency domain using Fourier Series Analysis. Changes in myelinated fibre potentials were detected as early as 2nd post-inoculation month. This technique could be further developed to aid in early diagnosis of leprosy.