Intracranial Group Research Articles

Experimental infection of T4 Acanthamoeba genotype determines the pathogenic potential.

T4 is the Acanthamoeba genotype most related to cases of granulomatous amoebic encephalitis (GAE) in immunocompromised patients and of keratitis in contact lens wearers. The determination of the pathogenic potential of Acanthamoeba clinical and environmental isolates using experimental models is extremely important to elucidate the capacity of free-living organisms to establish and cause disease in hosts. The aim of this study was to compare and evaluate the histopathology and culture between two different routes of experimental infection of T4 Acanthamoeba isolated from environmental and clinical source in mice (intracranial and intraperitoneal). Swiss isogenic healthy mice were inoculated with 10(4) trophozoites by intracranial (IC) and intraperitoneal (IP) routes and observed during 21days. The brains from animals inoculated by the IC route were collected and from the animals of the IP inoculation group, the brains, livers, kidneys, spleens, and lungs were removed. The organs were prepared and appropriately divided to be evaluated with histopathology and culture. There was no significant difference between the inoculation routes in terms of isolates recovery (χ(2) = 0.09; p = 0.76). In the IC group, isolate recovery rate was significantly higher in histopathology than the one achieved by culture (χ(2) = 6.45; p < 0.01). Experimental infection revealed that all isolates inoculated could be considered invasive because it was possible to recover evolutive forms of Acanthamoeba in both routes. This work represents the first in vivo pathogenicity assay of primary isolation source in Central region of Brazil showing in vivo pathogenicity and hematogenous spread capacity of these protozoa, improving the knowledge on free-living amoebae isolates.

Complications of Chronic Suppurative Otitis Media and Their Management: A Single Institution 12 Years Experience.

To determine the incidence of otogenic complications of Chronic suppurative otitis media (CSOM) and its management. The study was conducted at the tertiary referral centre and teaching hospital. An analysis was made about the clinical and operative findings, surgical techniques and approaches, the overall management and recovery of the patient. The data were then compared with the relevant and available literature. Over the study period of 12years, a total 45 cases of CSOM with complications were reviewed. Out of these 45 cases, 20 cases had extracranial (EC) while 25 cases had intracranial (IC) complications. The prevalence of each complication was 0.17 and 0.13%, IC and EC respectively. The commonly encountered IC complications were brain abscess, meningitis and lateral sinus thrombophlebitis. Among the EC complications, mastoid abscess followed by labyrinthitis and facial nerve palsy were encountered. The reliable warning signs and symptoms of IC complications were fever, headache, earache vestibular symptoms, meningeal signs and impairment of consciousness. Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus epidermidis were the common organism isolated. Cholesteatoma and granulation in the middle ear were the major findings in both groups of cases. Surgery was main modality of management of these conditions. We observed that two patients fail to regain full facial nerve function despite of surgery. Mortality rate was zero but morbidity was seen in 15% (3) and 28% (7) of cases in EC and IC group respectively. The epidemiological presentation, clinical features and results of treatment are discussed. CSOM complications, despite its reduced incidence still pose a great challenge in developing countries, as the disease present in the advanced stage leading to difficulty in management and consequently higher morbidity. In this study we emphasize the importance of the accurate and early diagnosis followed by adequate surgical therapy with multidisciplinary approach.

A Comparison of Different Murine Models for Cytomegalovirus‐Induced Sensorineural Hearing Loss

To compare three different inoculation techniques for the development of cytomegalovirus (CMV)-induced sensorineural hearing loss (SNHL) in a mouse model. A prospective experimental animal study. BALB/c mice underwent inoculation using green fluorescent protein-expressing mouse cytomegalovirus (mCMV-GFP) via transtympanic (TT), intraperitoneal (IP), or intracranial (IC) routes. Control mice received an equal volume of saline. Hearing thresholds were measured using both distortion product otoacoustic emissions (DPOAE) and evoked auditory brainstem response studies (ABR). Cochleas were harvested for histological examination and cytocochleogram. No mice in the TT or IP groups showed significant hearing loss. All infected mice in the IC group showed significantly elevated ABR and DPOAE thresholds at 4 weeks of age. Ten mice (55%) had profound hearing loss (≥80 dB) at 4 weeks of age, while the other eight mice (45%) initially showed moderate hearing loss (≤20 dB), which progressed to profound hearing loss by 6 to 8 weeks. Asymmetric hearing loss was seen in 40% of the mice. Temporal bone histology showed diffuse loss of outer hair cells (OHC). Green fluorescent protein (GFP)-labeled virus was abundant in the spiral ganglion and adjacent to the scala tympani at the basal region of the cochlea at 7 days postinjection, and devoid of GFP labeling by 14 days postinfection. Intracerebral injection of mCMV preferentially causes mCMV-mediated hearing loss relative to IP or TT injections. These results are consistent with the hearing loss reported in human congenital infection and may have implications for understanding the pathophysiology of CMV-mediated labyrinthitis.

White matter hyperintensities (WMH) are associated with intracranial atherosclerosis rather than extracranial atherosclerosis

There is increasing evidence for an association between WMH and large-artery atherosclerosis. We evaluated 268 patients with acute ischemic stroke to assess the relationship between intracranial (IC) atherosclerosis and WMH. The patients were classified into three groups according to the location of the stenosis; IC, extracranial (EC), and non-stenosis (NS) group. WMH were rated using the semiquantitative method of Scheltens and coworkers. The IC group had significantly more WMH score in comparison with the other groups after controlling age. The linear regression analysis showed that age was the factor most strongly associated with the total score of WMH; and the location of stenosis was positively related to WMH, especially in deep white matter. Our data show that IC stenosis is associated with WMH, indicating that IC stenosis, rather than EC stenosis, is likely to cause white matter lesions. These findings raise the possibility that occlusion of penetrating arteries, embolism to border-zone areas and a hemodynamic mechanism associated with IC stenosis leads to the formation of white matter lesions.

Classic Risk Factors for Atherosclerosis Are Not Major Determinants for Location of Extracranial or Intracranial Cerebral Atherosclerosis

Background: The prevalence of extracranial (EC) and intracranial (IC) atherosclerosis varies among races. Although several studies have sought to identify specific vascular risk factors that are associated with EC or IC atherosclerosis, the exact relationships are uncertain. This study aimed to determine if there are any specific risk factors for EC or IC atherosclerosis. Methods: For this study, we considered 3,349 consecutive patients who had been entered into a stroke registry between January 1999 and June 2007. After the exclusion of patients who had not undergone angiography, patients with cardiac sources of embolism or other causes of stroke, and non-Koreans, we had a total of 2,169 patients of single ethnicity with an angiographic analysis. Patients with atherosclerosis in both the IC and EC arteries (856 patients) were excluded. Finally, we identified 1,313 patients who had EC atherosclerosis (EC group, n = 256), IC atherosclerosis (IC group, n = 566) or normal angiographic findings (no-lesion group, n = 488). The frequency of risk factors and the demographic parameters were compared among these groups. Results: When compared to the normal group, the IC group was associated with older age and hypertension, and the EC group was associated with older age, higher initial blood sugar and low-density lipoprotein cholesterol levels. However, in a direct comparison between the IC and EC groups, we did not observe any significant risk factors or variables except for a higher frequency of males and higher total cholesterol levels in the EC group. Conclusions: Vascular risk factors may not be major determinants of location for atherosclerosis in the EC or IC arteries.

Extracranial and intracranial complications of suppurative otitis media. Report of 102 cases.

During the eight-year period, 1983-1990, 102 cases of intracranial (IC) and extracranial (EC) complications from 17 144 suppurative otitis media were reviewed. The prevalence of each complication was 0.24 and 0.45 per cent respectively. Facial paralysis, subperiosteal abscess and labyrinthitis were the common complications among the EC group, while meningitis and brain abscess were common in the IC group. Twenty five per cent of the EC group and 44 per cent of the IC group had more than two complications. The reliable warning signs and symptoms for IC complications were fever, headache, earache, vestibular symptoms, meningeal signs and impairment of consciousness. Proteus spp., Pseudomonas aeuruginosa and Staphylococcus spp. were the commonest organisms isolated from both groups. Cholesteatoma and granulation/polyp in the middle ear/mastoid were the major findings in both patient groups. Mortality rate in the IC group was 18.6 per cent. Morbidity rate in each group was 14.3 per cent (EC) and 27.9 per cent (IC) respectively. Epidemiological presentations, clinical features and the result of treatment are discussed.