Perilesional gliosis around solitary cerebral parenchymal cysticerci and long-term seizure outcome: a prospective study using serial magnetization transfer imaging

Purpose: Epilepsy following solitary cerebral cysticercosis (SCC) is possibly caused by perilesional gliosis, best visualized on magnetization transfer imaging (MTI).This study aims to describe development of gliosis around SCC by prospective serial MTI and to correlate this gliosis with long‐term seizure outcome. Methods: We randomized 123 patients with SCC and new‐onset seizures to treatment with albendazole plus antiepileptics (treatment), or antiepileptics only (control), and performed magnetic resonance imaging (MRI) scans at 0, 3, 6, 12, and 24 months. Prospective follow‐up data regarding seizure outcome up to 5 years later were collected. MRI studies were analyzed for lesion characteristics and perilesional magnetization transfer (MT) hyperintensity. Key Findings: Clinical and radiologic data of 77 patients were analyzed. Demographic and seizure characteristics were similar in treatment and control groups. Clinical data were available up to 64 months after enrollment. At 12 months, 89.5% patients were seizure‐free. MTI is more sensitive than routine imaging for detection of perilesional gliosis. Albendazole treatment did not affect imaging or clinical outcome, including development of gliosis. Independent of duration of follow‐up, gliosis was associated with more seizures, and with seizure recurrence at 12 months; duration of seizures and antiepileptic therapy was longer. Gliosis was not dependent on seizure type or stage of degeneration at enrollment or persistence/calcification of the lesion. Significance: Perilesional gliosis around SCC helps prognosticate seizure outcome. Poorer outcome in patients with persistent lesions is likely to be related to mechanisms other than gliosis. The lack of effect of albendazole on seizure outcome may be due to its inability to decrease formation of gliosis.     

Characterization of zebrafish full-length prothrombin cDNA and linkage group mapping

In this paper, we report the complete cDNA sequence of zebrafish prothrombin. The cDNA sequence predicts that zebrafish prothrombin is synthesized as a pre-proprotein consisting of a Gla domain, two kringle domains, and a two-chain protease domain. Zebrafish prothrombin is structurally very similar to human and other vertebrate prothrombins. Zebrafish and human prothrombin share 53% amino acid identity whereas zebrafish and hagfish prothrombin share 51% identity. Amino acid alignments of various prothrombins identified conservation of many of the functional/structural motifs suggesting that the vertebrate prothrombins may have similar functions. The three-dimensional structure of prothrombin predicted by homology modeling also revealed that the prothrombin fragment 1 and the catalytic domain structures are well conserved except for the insertion of an extra 7-amino-acid loop in the connecting region (CR) between the Gla and kringle I domain of fragment 1. Linkage analysis revealed that the prothrombin gene locus on linkage group 7 in zebrafish is syntenic to the human chromosome 11-prothrombin region suggesting its preservation through evolution. The availability of this cDNA sequence in zebrafish adds to our knowledge of the zebrafish hemostatic system and provides support for the view that similarities between zebrafish and mammalian coagulation exist, thus underscoring the relevance of the zebrafish model for studying human hemostasis.     

An immunogenicity, safety and post-marketing surveillance of a novel adsorbed human diploid cell rabies vaccine (Rabivax) in Indian subjects

In 1999, Serum Institute of India indigenously developed an adsorbed human diploid cell rabies vaccine (Rabivax). During 2000-04, this new vaccine was subjected to a series of immunogenecity and safety studies. Initially, an experimental batch of Rabivax (adsorbed) was assessed on ten healthy adult volunteers and its response was comparable with that of Merieux inactivated rabies vaccine (MIRV, lyophilized) which was used as a control. Subsequently, Rabivax (adsorbed) was assessed on forty-five suspect rabid dog bite cases with MIRV as control. The vaccine was found to be equally safe and immunogenic as MIRV and showed better rabies virus neutralizing antibody (RVNA) response on day 90 than MIRV. A post-licensing study conducted on 150 cases of suspect rabid animal bites showed it to be safe and immunogenic. To assess its long-term sero-efficacy some of these subjects tested after one year of follow up showed that 84% of them had adequate RVNA titers. In addition, a routine post-marketing surveillance done on 1608 animal bite cases demonstrated that Rabivax (adsorbed) was safe and efficacious. The adverse events to Rabivax (adsorbed) included pain at injection site (3.4%), swelling with induration (2.8%), fever and headache (1.4%). No serious adverse event was reported from the studies. In conclusion, Rabivax (adsorbed) is an immunogenic, safe and efficacious vaccine for rabies prophylaxis in humans.     

Immunogenicity and safety study of Indirab: A Vero cell based chromatographically purified human rabies vaccine

A chromatographically purified Vero cell rabies vaccine, Indirab manufactured by Bharat Biotech International Limited, Hyderabad, India was subjected to safety and immunogenicity studies by both intramuscular and intradermal routes of administration in parallel with a reference vaccine, Verorab. A Pre-exposure study was undertaken in 239 subjects by intramuscular (IM) route (Study I), Post-exposure study in 188 patients by intramuscular route (Study II) and Simulated post-exposure study in 134 subjects by intradermal (ID) route (Study III). All subjects in these studies were administered with either the test or the reference vaccine as per WHO approved intramuscular and intradermal regimens. The blood samples were collected on days 0, 14 and 35 in case of Study 1, and days 0, 14, 28 and 90 in case of studies II and III. In all studies both vaccine groups had adequate antibody titers (>0.5 IU/mL) on all days tested post-vaccination and there was no significant difference in the titers observed (p > 0.05). Some side effects like pain, induration, itching and fever were noted in both vaccine groups in all studies. Both vaccines were well tolerated. Hence it can be concluded that Indirab is as safe and immunogenic as Verorab when administered by both intramuscular and intradermal routes.     

Macroprolactinomas and epilepsy

OBJECTIVE: To assess the prevalence and characteristics of epilepsy in patients with macroprolactinomas. Secondly, to report the response to dopamine agonist (DA) therapy. PATIENTS: A case note analysis of all patients with a diagnosis of macroprolactinoma attending a neuroendocrine clinic between 1996 and 2006. Those with epilepsy at diagnosis of macroprolactinoma were examined in detail. RESULTS: There were 64 patients with macroprolactinoma and 29 of these had tumours with suprasellar extension compressing/invading the optic apparatus and/or surrounding brain structures. Six of these 29 patients (four men), had a history of seizures at the time of diagnosis, five of whom had features suggestive of temporal lobe epilepsy. None of the other 35 patients had epilepsy. All six patients with epilepsy had invasive prolactinomas on cranial imaging and marked hyperprolactinaemia (median prolactin 369 000 mU/l, range 28 000 to > 750 000). Seizures had been present for a median of 2 years (range 1-23 years) before the diagnosis of macroprolactinoma. A rapid reduction in seizure frequency occurred in all patients with initiation of DA therapy. Four have been seizure-free between 18 months to 15 years despite only small reductions in tumour size. CONCLUSIONS: Invasive macroprolactinomas can commonly be associated with epilepsy, particularly of temporal lobe origin. It is essential to enquire about epileptic symptoms, as the seizure disorder may have been undiagnosed/untreated for years. DA therapy can reduce ictal frequency and the doses of anti-epileptic drugs. Complete freedom from epilepsy can also occur.     

Comparison of saftey and immunogenicity of purified chick embryo cell rabies vaccine (PCECV) and purified vero cell rabies vaccine (PVRV) using the Thai Red Cross intradermal regimen at a dose of 0.1 ML

Intradermal (ID) vaccination with modern cell culture rabies vaccines is a means to significantly reduce the cost of post-exposure prophylaxis as compared to intramuscular vaccination. In this study we evaluated the efficacy, immunogenicity and tolerability of PCECV and PVRV administered ID in doses of 0.1 mL per site according to the 2-site Thai Red Cross (TRC) regimen. Patients with WHO category III exposure to suspect or laboratory proven rabid animals were administered either PCECV (n = 58) or PVRV (n = 52) ID at a dose of 0.1 mL per site at two sites on days 0, 3 and 7 and at one site on days 30 and 90. Serum samples were withdrawn on days 0, 14, 30, 90 and 180 and rabies virus neutralizing antibody (RVNA) titers were determined by rapid fluorescent focus inhibition test (RFFIT). Patients who were exposed to laboratory confirmed rabid animals were followed up for one year after exposure. All 110 patients developed RVNA titers above 0.5 IU/mL by day 14. Adequate titers >0.5 IU/mL were maintained up to day 180. Both vaccines induced equivalent RVNA titers at all time points and were well tolerated. Five subjects who were bitten by laboratory confirmed rabid dogs were alive and healthy one year after exposure. As demonstrated, PCECV and PVRV are both immunogenic, efficacious and well tolerated when administered in the TRC post-exposure prophylaxis regimen in ID doses of 0.1 mL as recommended by WHO guidelines. The use of PCECV in this regimen may prove more economical in developing countries like India.     

Demonstration of the extrinsic coagulation pathway in teleostei: Identification of zebrafish coagulation factor VII

It is not known whether the mammalian mechanism of coagulation initiation is conserved in fish. Identification of factor VII is critical in providing evidence for such a mechanism. A cDNA was cloned from a zebrafish (teleost) library that predicted a protein with sequence similarity to human factor VII. Factor VII was shown to be present in zebrafish blood and liver by Western blot analysis and immunohistochemistry. Immunodepletion of factor VII from zebrafish plasma selectively inhibited thromboplastin-triggered thrombin generation. Heterologous expression of zebrafish factor VII demonstrated a secreted protein (50 kDa) that reconstituted thromboplastin-triggered thrombin generation in immunodepleted zebrafish plasma. These results suggest conservation of the extrinsic coagulation pathway between zebrafish and humans and add credence to the zebrafish as a model for mammalian hemostasis. The structure of zebrafish factor VIIa predicted by homology modeling was consistent with the overall three-dimensional structure of human factor VIIa. However, amino acid disparities were found in the epidermal growth factor-2/serine protease regions that are present in the human tissue factor-factor VIIa contact surface, suggesting a structural basis for the species specificity of this interaction. In addition, zebrafish factor VII demonstrates that the Gla-EGF-EGF-SP domain structure, which is common to coagulation factors VII, IX, X, and protein C, was present before the radiation of the teleosts from the tetrapods. Identification of zebrafish factor VII significantly narrows the evolutionary window for development of the vertebrate coagulation cascade and provides insight into the structural basis for species specificity in the tissue factor-factor VIIa interaction.