CBF changes during brain activation: fMRI vs. PET

The changes in regional cerebral blood flow (rCBF) associated with the changes in neuronal activity are routinely measured both by positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) techniques. However, direct comparison has not been performed to determine similarities and differences of PET and fMRI techniques in determining the rCBF response to brain activation. In the present study, a quantitative comparison of the functional rCBF maps obtained by PET and fMRI are made by performing an activation study in a single group of subjects under precisely controlled conditions and using identical visual stimuli. Twelve healthy volunteers participated in the activation study using the visual checkerboard stimulation with flip frequency at 8 Hz. By selecting the conjunctive pixels which activated on both PET and fMRI maps, the change in rCBF measured by fMRI was 36.95 +/- 2.54%, whereas the value measured by PET was 38.79 +/- 2.63%. Our results have demonstrated that there is no statistically significant difference (P = 0.22) in the measurements of rCBF change between MRI and PET methods.     

Technetium-99m-L,L-ethylenedicysteine renal scan as a single-modality investigation for the evaluation of renal morphology and function: a comparative study with technetium-99m-dimercaptosuccinic acid

AIM: To evaluate whether cortical scars can be detected using the summed images of technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC) renal dynamic scan, and to compare the results with technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) scan. To evaluate the inter-observer variability for 99mTc-L,L-EC and 99mTc-DMSA scan reporting. METHODS: One hundred and three patients were initially included in the study; 21 were excluded, five due to a single functioning kidney and 16 due to impaired renal function (serum creatinine>2.5 mg.dl(-1)). Eighty-two patients (39 females, 43 males), including 31 children, with a mean age of 33.4+/-11.3 years (range, 4 months to 74 years), underwent both 99mTc-DMSA and 99mTc-L,L-EC scintigraphy within a period of 14 days. 99mTc-L,L-EC images were regrouped into 2 min image sets, and the initial 2 min summed image (cortical phase) was used for the evaluation of scars. Three independent observers analysed both images separately on different days without being aware of the identity and clinical details of the patients. Their 99mTc-L,L-EC findings were compared with the consensus 99mTc-DMSA scan findings taken as reference. RESULTS: The overall sensitivity of 99mTc-L,L-EC scans was 93% and the specificity was 96%. The inter-observer variability was 0.91 for 99mTc-L,L-EC and 0.94 for 99mTc-DMSA scan reporting, using the weighted kappa analysis at P<0.05. CONCLUSIONS: 99mTc-L,L-EC is an excellent single-modality comprehensive investigational agent for renal morphology, function and outflow tract evaluation with the added advantages of lower cost, convenience and low radiation exposure to the patient.     

Endogenous recovery of injured spinal cord: longitudinal in vivo magnetic resonance imaging

Pathological changes were followed longitudinally with in vivo magnetic resonance imaging (MRI) and behavioral studies in experimental spinal cord injury (SCI). MRI-observed pathology was correlated with histology. On MRI, the cavitated regions of the injured cord were gradually filled with viable tissue between two and 8 weeks postinjury, and a concomitant improvement was observed in the neurobehavioral scores. By weeks 3-6, on MRI, the gray matter (GM) returned in the segments caudal, but not rostral, to the injury site. The corresponding histological sections revealed motor neurons as well as other nuclei in the gray matter immediately caudal to the epicenter, but not at the site of injury, suggesting neuronal recovery in perilesioned areas. The neuronal and neurological recovery appeared to occur about the same time as neovasculature that was reported on the contrast-enhanced MRI, suggesting a role for angiogenesis in recovery from SCI. The role of angiogenesis in neuronal recovery is further supported by the immunohistochemical observation of greater bromodeoxyuridine uptake by blood vessels near the lesion site compared with uninjured cords.     

Patterns of uveitis in children presenting at a tertiary eye care centre in south India

PURPOSE: To study the patterns of uveitis in the paediatric age group in a referral eye care centre in south India. MATERIALS AND METHODS: Thirty-one patients 15 years or younger with uveitis, examined in the year 2000, were included in this study. The uveitis was classified according to the anatomical site of ocular involvement and the most probable aetiological factor. The final diagnosis was based on clinical manifestations and results of specific laboratory investigations. RESULTS: A total 31 (6.29%) paediatric uveitis cases were seen among the 493 uveitic cases in the year 2000. The male:female ratio was 17:14. Anterior (9 cases), intermediate (9 cases) and posterior uveitis (9 cases) were seen in equal number. Four patients had panuveitis. Twenty-seven patients had visual acuity of 6/36 or better at presentation. Approximately 25% (8 of 31) patients had cataract secondary to inflammation. Immunosuppressives were administered in 4 patients and one patient required cataract surgery. CONCLUSION: Uveitis in children comprises approximately 6% of uveitis cases in a referral practice in south India. Anterior, intermediate and posterior uveitis are seen in equal numbers. We recommend that intermediate uveitis be ruled out in all cases of anterior uveitis by careful clinical evaluation including examination under anesthesia (EUA) when required.     

Natural radioactivity in the soil samples of Coastal Karnataka of South India

Studies on radiation level and radionuclide distribution in the region of Coastal Karnataka, India, were undertaken. The purpose of this study is to provide baseline data on radiation level and radionuclide distribution in the region for the future assessment of the impact of the nuclear and thermal power stations that are being set up in the region. Further, this study may reveal information on the transportation of radionuclides in the environment. The external gamma dose rates in air have been measured throughout Coastal Karnataka using a sensitive plastic scintillometer. The measured dose rates include both terrestrial and cosmic ray components. The gamma dose rates in air range from 26 to 174 nGy h(-1) with a median value of 74 nGy h(-1). The activities of naturally occurring radionuclides in the soil samples of the region were measured using HPGe gamma ray spectrometry, and the resulting doses in air were calculated. The activity of 40K varies from 61.0 to 316.7 Bq kg(-1) with a median of 117.5 Bq kg(-1); the activity of 226Ra varies from 20.1 to 62.3 Bq kg(-1) with a median value 35.0 Bq kg(-1) and that of 232Th from 14.3 to 48.6 Bq kg(-1) with a median value of 29.8 Bq kg(-1). The mean absorbed dose rate in air due to naturally occurring radionuclides is found to be 41.5 nGy h(-1). In addition to this, the correlations between 226Ra and 40K, 232Th and 40K, and 226Ra and 232Th were computed from the results of the concentration of these naturally occurring radionuclides. A weak correlation was observed between 226Ra and 40K and between 232Th and 40K while a moderately good correlation was observed between 226Ra and 232Th. The results of these systematic investigations are presented and discussed in this paper.     

Induction of seminiferous tubular atrophy by single dose of 5-fluorouracil (5-FU) in Wistar rats

Antimetabolite, 5-fluorouracil (5-FU) is known to cause testicular damage by epithelial sloughing and cell killing. However, it is not known whether 5-FU induces tubular atrophy and the fate of exfoliated germ cells. Present study was conducted to evaluate these effects of 5-FU on rat testis. Animals were injected, single dose of 5-FU (10.50 & 100 mg/kg, i.p.) and sampled at 1, 3, 15 and 30 day following the treatment. The testes were perfusion fixed by Bouin's fluid. Five micron thick paraffin sections of testes and epididymis were stained with haematoxylin and eosin. Slides were examined for the incidence of abnormal tubules (per 200 tubules), tubular diameter (STD), epithelial height (SEH) and for the presence of germ cells in the epididymis. Data were analysed by Mann-Whitney 'U' test. The testes weight, STD, SEH were decreased (P < 0.05-0.01) in treated animals. The abnormal tubules were increased in a dose dependent manner with atrophic tubules seen on 30 d. The exfoliated germ cells have not blocked the post testicular ductal system and found in the epididymis in a dose dependent manner. The present study concludes that 5-FU causes tubular shrinkage and atrophy. Further, epididymis is involved in the phagocytosis of germ cells.     

Stomal recurrence in patients with T1 glottic cancer after salvage laryngectomy for radiotherapy failures: role of p53 overexpression and subglottic extension

The role of p53 overexpression in the development of stomal recurrence was studied in patients with T1 glottic cancer who had undergone salvage laryngectomy after primary radiotherapy failure (first recurrence). The role of subglottic extension of the recurrent tumor in the development of stomal recurrence was also studied. One hundred fourteen patients with T1 squamous cell carcinoma of the glottic larynx were irradiated with curative intent. A local recurrence (first recurrence) developed in 23 patients (20%), and salvage laryngectomy was performed for 20 of these patients. No postlaryngectomy radiation therapy was included in the treatment of recurrences. Several risk factors thought to be significant in the development of stomal recurrence were analyzed in these 20 patients. Prognostic factors analyzed include: p53 overexpression in the preradiation biopsy specimen, subglottic extension of the first recurrence, thyroid cartilage and lymph node involvement at the time of first recurrence, emergency tracheostomy performed before salvage laryngectomy, and the laryngectomy procedure performed for first recurrence. Presence of p53 protein in the preradiation biopsy specimen of laryngeal cancer did not show any adverse effect on the development of stomal recurrence. Stomal recurrence developed in 27% of patients with positive biopsies and in 20% of patients with negative biopsies (p = 1.00). Subglottic extension of the first recurrence was associated with an increased incidence of stomal recurrence. Rates of stomal recurrence were 6% in patients without subglottic extension and 100% in patients with subglottic extension (p = 0.001). All other risk factors studied showed no effect on stomal recurrence. In this study, p53 overexpression showed no effect on the development of stomal recurrence after salvage laryngectomy in patients with T1 glottic cancer. Conversely, subglottic extension of the recurrence was found to be strongly associated with stomal recurrence. All other factors analyzed showed no effect on stomal recurrence.     

一阶导数光谱法测定盐酸地尔硫缓释片的含量

目的:建立测定盐酸地尔硫艹卓缓释片的含量测定方法。方法:以乙醇为溶剂,以一阶导数光谱的谷-零位值法测定盐酸地尔硫艹卓的含量,测定波长λ谷=2 50±1nm。结果:回收率100.01% ,RSD0.38%～0.47% ,线性范围2.4～16.8μg/ml。结论:方法简便、快速、准确,适合于该制剂的含量测定。     

The cranial-spinal junction in medulloblastoma: does it matter?

PURPOSE: Late effects of treatment in children and young adults with medulloblastoma can be influenced by the technique employed in radiating the craniospinal axis. The purpose of this study is to determine whether the placement of the cranial-spinal junction has an impact on dose to the cervical spinal cord and surrounding organs. METHODS AND MATERIALS: Five patients underwent computed tomography (CT) simulation in the prone position for craniospinal irradiation. A dose of 36 Gy was prescribed to the entire neuraxis. The doses to the cervical spinal cord and surrounding organs were calculated using a cranial-spinal junction at the C1-C2 vertebral interspace (high junction) or at the lowest point in the neck, with exclusion of the shoulders in the lateral cranial fields (low junction).The volume of critical organs at risk, as well as dose to these structures using the cranial and spinal field(s) were outlined and calculated using the CMS FOCUS 3-dimensional treatment planning system. RESULTS: The average dose to the cervical spinal cord was 11.9% higher than the prescribed dose with the low junction, and 6.7% higher with the high junction. However, doses to the thyroid gland, mandible, pharynx, and larynx were increased by an average of 29.6%, 75.8%, 70.6%, and 227.7%, respectively, by the use of the high junction compared to the low junction. CONCLUSION: A higher dose to the cervical spinal cord can be minimized by using a high junction. However, this would be at the cost of substantially increased doses to surrounding organs such as the thyroid gland, mandible, pharynx, and larynx. This can be critical in children and young adults, where hypothyroidism, mandibular hypoplasia, and development of second malignancies may be a late sequela of radiation therapy.