Study of variance and covariance terms in linear attenuation coefficient measurements of irregular samples through the two media method by gamma-ray transmission.

The two media method permits the application of Beer's law (Thesis (Master Degree), Universidade Estadual de Londrina, PR, Brazil, pp. 23) for the linear attenuation coefficient determination of irregular thickness samples by gamma-ray transmission. However, the use of this methodology introduces experimental complexity due to the great number of variables to be measured. As consequence of this complexity, the uncertainties associated with each of these variables may be correlated. In this paper, we examine the covariance terms in the uncertainty propagation, and quantify the correlation among the uncertainties of each of the variables in question.     

The effect of L-dopa on the potentiation of radiation damage to human melanoma cells

Since L-dopa (L-3,4-dihydroxyphenylalanine) has been shown to possess a selective toxicity for melanoma cells both in vitro and in vivo, we have examined the combined effect of L-dopa and radiation on human melanoma cells. It was found that the combined use of L-dopa potentiated the radiation cytotoxicity to HMV-I human melanoma cells, compared with the response seen in non-melanoma HeLa S3 cells. In HMV-I cells during their exponential phase, L-dopa decreased the shoulder width of the radiation survival curve significantly. In addition, L-dopa significantly inhibited the repair of potentially lethal damage (PLD) in HMV-I cells during their plateau phase. When the distributions of the G1, S, and G2-M cells were measured 24 h after combined L-dopa and radiation treatment, there was significant increase in the accumulation of cells in the G2-M phase of the cell cycle, compared to cells that received either L-dopa or radiation treatment only.     

Possible radiation induced cancer of the thoracic esophagus after postoperative irradiation in breast cancer

We report 11 cases with cancer of the thoracic esophagus developing after postoperative irradiation therapy for the breast cancer. Irradiation was done immediately after mastectomy in these cases and the irradiation field included the unilateral or bilateral parasternal region. They received a total dose ranging from 35 Gy to 60 Gy and the dose received to the thoracic esophagus was estimated from 10 Gy to 48 Gy. All cancer sites were involved in the irradiation filed. The latent intervals of 10 cases from radiation to the manifest of cancer ranged between 10 to 19 years. Among 4777 women undergone mastectomy for breast cancer between 1946 and 1980 in our hospital, 8 women (0.17%) developed cancer of the thoracic esophagus, whereas 5 (0.335%) out of 1534 women treated with mastectomy and radiotherapy with Linac between 1964 and 1980 developed cancer of the thoracic esophagus. Higher incidence of esophageal cancer in patients treated with surgery and radiation suggests that these cancers might be induced by radiation. Eight patients had esophagectomy and 4 patients of them received postoperative irradiation. They have survived from 9 months to 13 years. Two patients were controlled well by the irradiation alone. It is interesting that radiation therapy is sensitive to the possible radiation induced cancer of the thoracic esophagus. Follow up study should be directed to the possible development of second malignancy in patients who survive for a long time after radiation therapy.     

A case of sensory ataxic neuropathy and polymyositis of perivascular type associated with Sj?gren's syndrome]

A 53-year old woman was admitted with of sensory disturbance and weakness of lower limbs which had progressed slowly in the previous ten years. A diagnosis of sensory ataxic neuropathy associated with Sj?gren's syndrome was made. A sural nerve biopsy showed marked loss of myelinated fibers. A muscle biopsy revealed atrophy of muscle fibers along with perivascular cellular infiltration. The dorsal root ganglia have been considered to be the main site affected in the ataxic neuropathy in Sj?gren's syndrome. However, the evidence for that was meager. The perivascular inflammatory change observed in the muscle may also have existed in the peripheral nervous system including the dorsal root ganglia.     

Lysosomal generation of amyloid β protein species in transgenic mice

Soluble amyloid β protein (Aβ)1–40 and highly amyloidogenic Aβ1–42/43 were immunocytochemically labeled in lysosomes of acinar cells and macrophages in the pancreas of transgenic mice systemically expressing a C-terminal fragment of the Aβ precursor. Aβ1–42/43 and long Aβ species extending their C-termini were detected in the detergent-insoluble fraction. Immunoreactivity of cathepsin D was markedly increased in lysosomes filled with Aβ fibrils. These findings indicated that Aβ1–40, Aβ1–42, Aβ1–43 and longer Aβ species were generated in the lysosomes of the transgenic pancreas, and suggested that the activation of cathepsin D, a candidate γ-secretase, leads to acceleration of Aβ amyloid formation.     

Cytoskeletal proteins abnormalities in olivopontocerebellar atrophy]

A highly sensitive silver technique for glial cytoplasmic inclusions in olivopontocerebellar atrophy (OPCA) was applied to 15 subjects with neurodegenerative disorders including 4 patients with OPCA, 4 patients with Joseph disease and with 3 normal control subjects, and the argyrophilic structures in the OPCA cases were immunocytochemically examined. As a result, the argyrophilic structures were found in the OPCA cases and Alzheimer cases. The argyrophilic structures included the white matter oligodendroglia, and neurons, astroglia and oligodendroglia in the putamen, pontine nucleus and inferior olivary nucleus. The pontocerebellar tracts and the surrounding white matter of the inferior olivary nucleus contained a small number of argyrophilic nerve fibers with a hollow structure, which were interpreted as myelin. Immunocytochemistry demonstrated that the oligodendroglia in the white matter had immunoreactivities to an paired helical filament (PHF), microtubule associated protein 5 (MAP5), tau and ubiquitin antiserum, and the astroglia in the white matters had an immunoreactivity to a MAP5 antiserum. In the putamen, pontine nucleus and inferior olivary nucleus, in addition to the immunoreactivities observed in the oligodendroglia, the neurons were immunoreactive for PHF, MAP5, tau and ubiquitin antisera, and the astroglia had the same immunoreactivities as the neurons except for being tau negative in the putamen. The nerve fibers in the pontocerebellar tract and inferior olivary nucleus capsule were strongly positive for myelin basic protein and negative for PHF antiserum. These findings indicate that the Gallyas positive argyrophilia in the OPCA subjects is closely associated with PHF or tau.     

Evoked magnetic fields as a tool to optimize therapeutic electrical stimulation of the sacral surface

Magnetoencephalography (MEG) was used to measure the somatosensory evoked fields in six healthy males undergoing sacral surface therapeutic electrical stimulation, a recently introduced treatment for chronic urinary dysfunction. This study was performed to investigate the utility of MEG to optimize the stimulation parameters. Strong or weak electrical stimuli were applied to small or large surface electrodes placed over the bilateral sacral surfaces. The peak latency and strength of the equivalent current dipole were evaluated at the first peak originating from the primary somatosensory cortex (M30). There was no difference in M30 latency in response to stimulation intensity or electrode size. However, a larger equivalent current dipole strength was obtained in response to higher stimulus intensities, which indicated a more effective stimulus on the sacral surface. The present MEG study shows that stronger stimuli given through large electrodes evoke larger responses than small stimuli through small electrodes. The study also suggests that MEG can be used as an objective tool to monitor whether therapeutic stimulation parameters are appropriate.     

Elevated levels of pro-inflammatory cytokines in coronary artery thrombi

To validate the hypothesis that artery sites occluded with thrombi release pro-inflammatory cytokines, we measured concentrations of interleukin (IL)-6 and IL-8 in infarct-related coronary artery thrombi and atherosclerotic plaque specimens obtained with a transluminal extraction catheter (TEC) from cases of acute myocardial infarction (MI). Fifteen patients (group I) were enrolled in the study and four sets of samples were obtained (taken from the right atrium both before and after angioplasty, from infarct-related coronary artery thrombi and atherosclerotic plaque aspirated with a TEC and from the thoracic aorta aspirated with a TEC). Ten patients undergoing elective TEC served as controls (group II). IL-6 and IL-8 were measured in all patients by means of an enzyme-linked immunosorbent assay. Both IL-6 and IL-8 levels of infarct-related coronary artery samples in group I were significantly higher than in group II (mean ± SEM, 15.3 ± 4.5 vs. 3.8 ± 1.2 pg/ml; P < 0.01 and 44.0 ± 2.4 vs. 15.6 ± 0.6 pg/ml; P < 0.001, respectively). The results suggest that pro-inflammatory cytokines originate from occluded coronary arteries in acute MI.