Haemodynamic enhancement in perforator flaps: the inversion phenomenon and its clinical significance. A study of the relation of blood velocity and flow between pedicle and perforator vessels in perforator flaps.

Perforator flaps are perfused through a long vessel whose calibre decreases from its origin to the skin, because all branches have been sealed, resulting in a conduit with resistances in series, rather than a tree with resistances in parallel, as in the normal systemic circulation. This study was planned to assess whether the differences between perforator flap and normal systemic vasculature have an impact on haemodynamic parameters in perforator flaps and on their clinical significance. The study was performed on 10 patients. Echo-colour-Doppler measurement of diameters, velocity of flow and calculations of flow rate were made at the level of flap pedicle artery and skin perforator artery, pre- and post-operatively in each patient. Statistical analysis used the Wilcoxon matched pairs signed sum rank test. Our data show that in the donor area pre-operatively, blood velocity in skin artery perforator is lower that in the corresponding pedicle artery, whereas post-operatively, in perforator flaps, blood velocity in the perforator is higher than in the pedicle. The difference was statistically significant (P<0.01). There is an inversion of the gradient of blood velocity between pedicle artery and perforator artery compared to normal circulation. Furthermore, in normal circulation flow through the perforator was found smaller than that at the pedicle, whereas in perforator flaps, flow through the perforator is smaller but is a greater proportion of the flow through the pedicle and the difference is statistically significant (P<0.01). Therefore, the velocity of blood and the rate of flow reaching the skin are higher in perforator flaps than in normal circulation.     

Pathophysiology of spasticity

Neurological Sciences - Spasticity arises from lesions involving the corticoreticulospinal system in the brain, brainstem or spinal cord. Abnormal suprasegmental influences lead to increased spinal...     

Semi-empirical systematics of (n,3He) reaction cross-section at 14.6 and 20 MeV.

A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.     

Electroencephalographic and imaging profile in a subacute sclerosing panencephalitis (SSPE) cohort: a correlative study.

OBJECTIVE: There are only a few studies correlating diverse radiological and EEG features of subacute sclerosing panencephalitis (SSPE). The objective of the study was to (a) describe EEG profile and (b) correlate it with the clinical and imaging data of patients with confirmed SSPE. METHODS: This study was conducted at a University teaching hospital in south India and involved 58 patients (M:F=37:21, age: 12.3, SD 4.8 years) of SSPE. Diagnosis of SSPE was based on the characteristic clinical manifestations, and raised IgG (1:625) anti-measles antibody in cerebrospinal fluid (CSF) by ELISA in all the patients. Scalp EEGs were recorded on 16 channel machines using standard parameters and procedures. The EEG, clinical and imaging data were reviewed. RESULTS: EEGs were frequently abnormal: typical (37) and atypical (21). Diffuse slowing of background activity (BGA) was noted in 46 records being asymmetrical in six. Periodic complexes were periodic (32), quasi-periodic (21) or a-periodic (4). Periodic complexes (PC) (amplitude: 370.7, SD 171.2 microV; duration - 1.7, SD 2.0 s; inter-complex interval: 8.4, SD 9.2s) were symmetrical in 39 and asymmetrical in 19. CT (32) and MRI (23) scans were normal in 16 patients while others had white matter (15), cerebral edema (8), cerebral atrophy (8), basal ganglia (2), and thalamic (2) changes. There was an independent association of frontally dominant slowing of BGA (p=0.04) and typical PCs (p=0.03) with the diffuse cerebral edema on imaging. White matter changes correlated with slowing of BGA (p=0.04), but not with typical PC (p=0.16). CONCLUSIONS: This study provides valuable insight into the structural and clinical correlates of EEG changes in SSPE. SIGNIFICANCE: Irrespective of the incidence of occurrence of SSPE in a community, a clinician should be aware of the wide spectra of EEG findings. This study also discusses the possible underlying structural and clinical correlates.     

Tuberculosis trends in Madrid, 1994-2003: impact of immigration and HIV infection.

SETTING: Tuberculosis (TB) cases reported from nine districts of Madrid, where the percentage of immigrant population varied from 1.9% in 1996 to 12.2% in 2003. OBJECTIVE: To describe the trends in TB incidence from 1994 to 2003. DESIGN: Observational study. RESULTS: Between 1994-1995 and 2002-2003, the TB rate decreased from 48.5 (95% CI 45.8-51.1) to 23.3 per 100000 population (95% CI 21.5-25.1) (P < 0.001). The percentage of TB cases co-infected with HIV decreased from 55.9% in 1994 to 14.3% in 2003 (P < 0.001), whereas TB cases in foreigners increased from 2.6% in 1994 to 33.7% in 2003 (P < 0.001). CONCLUSION: Although the TB rates showed a marked decrease in the study period, the increasing impact of immigration contributed to slowing down the trend.