Role of the right and left hemispheres in recovery of function during treatment of intention in aphasia

Two patients with residual nonfluent aphasia after ischemic stroke received an intention treatment that was designed to shift intention and language production mechanisms from the frontal lobe of the damaged left hemisphere to the right frontal lobe. Consistent with experimental hypotheses, the first patient showed improvement on the intention treatment but not on a similar attention treatment. In addition, in keeping with experimental hypotheses, the patient showed a shift of activity to right presupplementary motor area and the right lateral frontal lobe from pre- to post-intention treatment functional magnetic resonance imaging (fMRI) of language production. In contrast, the second patient showed improvement on both the intention and attention treatments. During pre-treatment fMRI, she already showed lateralization of intention and language production mechanisms to the right hemisphere that continued into post-intention treatment imaging. From pre- to post-treatment fMRI of language production, both patients demonstrated increased activity in the posterior perisylvian cortex, although this activity was lateralized to left-hemisphere language areas in the second but not the first patient. The fact that the first patient's lesion encompassed almost all of the dominant basal ganglia and thalamus whereas the second patient's lesion spared these structures suggests that the dominant basal ganglia could play a role in spontaneous reorganization of language production functions to the right hemisphere. Implications regarding the theoretical framework for the intention treatment are discussed.     

Controlled tetra-Fc sialylation of IVIg results in a drug candidate with consistent enhanced anti-inflammatory activity

Despite the beneficial therapeutic effects of intravenous immunoglobulin (IVIg) in inflammatory diseases, consistent therapeutic efficacy and potency remain major limitations for patients and physicians using IVIg. These limitations have stimulated a desire to generate therapeutic alternatives that could leverage the broad mechanisms of action of IVIg while improving therapeutic consistency and potency. The identification of the important anti-inflammatory role of fragment crystallizable domain (Fc) sialylation has presented an opportunity to develop more potent Ig therapies. However, translating this concept to potent anti-inflammatory therapeutics has been hampered by the difficulty of generating suitable sialylated products for clinical use. Therefore, we set out to develop the first, to our knowledge, robust and scalable process for generating a well-qualified sialylated IVIg drug candidate with maximum Fc sialylation devoid of unwanted alterations to the IVIg mixture. Here, we describe a controlled enzymatic, scalable process to produce a tetra-Fc–sialylated (s4-IVIg) IVIg drug candidate and its qualification across a wide panel of analytic assays, including physicochemical, pharmacokinetic, biodistribution, and in vivo animal models of inflammation. Our in vivo characterization of this drug candidate revealed consistent, enhanced anti-inflammatory activity up to 10-fold higher than IVIg across different animal models. To our knowledge, this candidate represents the first s4-IVIg suitable for clinical use; it is also a valuable therapeutic alternative with more consistent and potent anti-inflammatory activity.Intravenous immunoglobulin (IVIg) is a therapeutic blood product prepared from the pooled plasma of 3,000–60,000 healthy donors per batch (1–3). It is a complex heterogeneous mixture of IgG subclasses and low amounts of IgA, IgM, and other plasma proteins (4). IVIg contains a wide array of antibodies expected to be present in human serum, and the large number of donors ensures diversity in the Ig repertoire that far exceeds that of an individual donor (5).IVIg has been used for more than 30 years for the treatment of a variety of acute and chronic autoimmune and systemic inflammatory diseases (2–5). Although efficacious in these diseases, the precise mechanism of action of IVIg is not well-understood. Various studies have documented a series of nonmutually exclusive mechanisms modulating components of the innate and adaptive immune system (4, 6). For example, IVIg has been shown to mediate anti-inflammatory responses through its action on dendritic cells, natural killer cells, regulatory T cells, B cells, and the monocyte/macrophage system, and through its suppression or neutralization of soluble factors, such as inflammatory cytokines, chemokines, and pathogenic autoantibodies (5–7).Although beneficial in numerous indications, IVIg preparations have distinct limitations, such as variable efficacy, clinical risks, high costs, and finite supply (2, 3, 8). Different IVIg preparations are frequently treated as interchangeable products clinically, but it is well-known that significant differences in product preparations exist that may impact tolerability and activity in selected clinical applications (9). At the current maximal dosing regimens, only partial and unsustained responses are obtained in many instances (2, 4). In addition, the long infusion times (4–6 h) associated with the high volume of IVIg treatment consume significant resources at infusion centers (8) and negatively affect patient-reported outcomes, such as convenience and quality of life (10). Developing therapeutic alternatives that could leverage the broad biological activities of IVIg and simultaneously, provide more consistent and potent anti-inflammatory activity with minimal inconvenience would be highly valuable to clinicians and patients.The IgGs in IVIg are composed of a fragment antigen-binding domain (Fab fragment) that facilitates the selective interaction with specific antigens and a fragment crystallizable domain (Fc fragment) that interacts with cellular receptors (Fc receptors) known to play critical functions in modulating the activation state of immune cells (11). The IgG Fc fragment contains a conserved N-linked glycan at position N297. The core of the N297 N-linked glycan is composed of two GlcNAc and three mannose residues. Typically, this core can be further extended with fucose, galactose, sialic acid, and bisecting GlcNAc monosaccharides through selective enzymatic glycosylation reactions (12, 13). Alterations to the N297 glycan composition have been shown to have a significant impact in modulating the interaction between the IgG Fc fragment and the Fc receptors. For example, removal of fucose from the IgG N-glycan core has been shown to increase its affinity for Fc gamma receptor IIIa (FcγRIIIa), leading to enhanced antibody-dependent cellular cytotoxicity (14). Sialylation, the addition of terminal sialic acid to N297 glycan, has also been shown to decrease the affinity for type I Fc receptors and increase the affinity for type II Fc receptors (11).In the past three decades, a wealth of reports has documented alterations in antibody glycosylation associated with different diseases in humans. Among these reports, changes in antibody sialylation have been associated with the evolution of autoimmune and inflammatory diseases. For example, rheumatoid arthritis and juvenile idiopathic arthritis are associated with decreased levels of IgG sialylation (15, 16). Additional studies have shown that this translates particularly to the pathogenic antibodies in inflamed joints of arthritis patients (17). It has also been shown that IgG sialylation increases during pregnancy and that this increase may be associated with the remission of rheumatoid arthritis during pregnancy (18, 19). In addition, pathogenic proteinase 3 autoantibodies are less sialylated in patients with active Wegener’s vasculitis (granulomatosis with polyangiitis) (20).Alterations in endogenous IgG sialylation have been associated with treatment response in inflammatory/autoimmune diseases. For example, in patients with Kawasaki disease treated with IVIg, increased levels of endogenous human IgG sialylation decreased the likelihood of IVIg treatment resistance (defined as persistent or recrudescent fever at least 36 h after the completion of IVIg infusion) (21). Similarly, in patients with Guillain–Barré syndrome, those with more severe forms of the disorder showed a lower level of IgG sialylation, despite IVIg treatment (22).Translation of these natural observations in humans to therapeutic options was first realized in 2006, when it was proposed that high doses (>1 g/kg) of unfractionated IVIg were required to elicit sufficient anti-inflammatory activity because of a limited concentration of sialylated IgG in the total IVIg preparation. This theory was substantiated in a mouse model of arthritis that showed similar levels of anti-inflammatory activity when using 1 g/kg IVIg and 0.1 g/kg sialic acid-enriched IVIg, therefore indicating a 10-fold enhancement with the addition of terminal sialic acids (23, 24). Additional results supporting this theory were subsequently reported in other independent studies and other animal models (25, 26). It was further shown that the anti-inflammatory activity of sialylation can be recapitulated using a sialylated Fc fragment derived from IVIg or an IgG1 recombinant antibody (after in vitro sialylation of the Fc) at a 30-fold lower dose than IVIg (24, 27). These results opened the possibility of developing sialylated IVIg and other sialylated antibodies with enhanced anti-inflammatory properties.In recent years, different reports have debated the anti-inflammatory benefits of sialylation. For example, studies using desialylated IVIg in immune thrombocytopenic purpura (ITP) models (28) and Sambucus nigra agglutinin (SNA) -enriched IVIg in arthritis models (29) have shown that sialylation does not enhance IVIg activity or that it may even be dispensable for its therapeutic effects. On the contrary, more comprehensive studies performed by several independent laboratories testing desialylated or hypersialylated IVIg across different animal models under preventive and therapeutic treatment modalities have shown that sialylation is critical for the anti-inflammatory activity of IVIg (24–27, 30). Furthermore, T cell-independent vaccinations resulted in the generation of hypersialylated immunomodulatory antibodies that were able to modulate other immune responses, establishing a broad relevance of these sialylated IgG glycoforms as modulators of immune responses (31). Notably, none of the previous studies used precisely the same protocols for enriching or depleting sialic acid-containing IgG glycoforms, which may partially explain the discrepancies of these studies. Thus, the major aim of this study was to use rigorous, controlled processes and quality controls to investigate the potential of hypersialylated IVIg as a drug candidate with enhanced therapeutic activity.We describe a robust, controlled sialylation process to generate tetra-Fc–sialylated IVIg and show that this process yields a product with consistent enhanced anti-inflammatory activity. Specifically, we first observed that the sialylated IVIg was at least 10 times more potent than the parent IVIg product in a model of collagen antibody-induced arthritis (CAIA) using a prophylactic dose. We further confirmed this enhanced anti-inflammatory activity with therapeutic dosing in models of K/BxN serum-induced arthritis and ITP, and a prophylactic model of skin-blistering disease. Importantly, we noted that, without a tightly controlled process of sialylation, unwanted side products can accumulate that may be responsible for the inconsistent activity observed in previous studies. Therefore, the process that we describe combined with sensitive controls to generate a tetra-Fc–sialylated IVIg (s4-IVIg) devoid of undesired modifications has been critical to obtain the consistent enhanced anti-inflammatory activity and serves as the first example, to our knowledge, of a therapeutic candidate for product development.     

Semantic monitoring of words with emotional connotation during fMRI: contribution of anterior left frontal cortex.

Previous studies showed that cortex in the anterior portions of the left frontal and temporal lobes participates in generating words with emotional connotations and processing pictures with emotional content. If these cortices process the semantic attribute of emotional connotation, they should be active whenever processing emotional connotation, without respect to modality of input or mode of output. Thus, we hypothesized that they would activate during monitoring of words with emotional connotations. Sixteen normal subjects performed semantic monitoring of words with emotional connotations, animal names, and implement names during fMRI. Cortex in the anterior left frontal lobe demonstrated significant activity for monitoring words with emotional connotations compared to monitoring tone sequences, animal names, or implement names. Together, the current and previous results implicate cortex in the anterior left frontal lobe in semantic processing of emotional connotation, consistent with connections of this cortex to paralimbic association areas. Current findings also indicate that neural substrates for processing emotional connotation are independent of substrates for processing the categories of living and nonliving things.     

Shigellosis in children—prevalence of subgroups and antibiotic resistance

Study of 468 cases of shigellosis in a rural hospital showed that the children in the age group of 1–10 years were maximally affected. The 28 strains of shigella isolated, belonged to all the four subgroups with preponderance of Sh. dysenteriae type I (50%), followed by Sh flexneri (42·50%). Only a single strain each of Sh. boydii (3·57%) and of Sh. sonnei) (3·57%) were isolated. The sensitivity was highest (100%) with gentamycin, furazolidone and cotrimoxazole followed by neomycin (96·4%) and kanamycin (96·4%). The resistance was highest with tetracycline (89·29%) followed by streptomycin (85·72%), ampicillin (67·86%) and chloramphenicol (64·29%). Multi drug resistance, possibly plasmid-mediated was observed and the four drug resistance pattern (ACST) was prevalent (42·85%).     

Utility of in vitro proton magnetic resonance spectroscopy in aetiological characterisation of brain abscesses

Purpose: Brain abscesses often present an aetiological dilemma. Microscopy is insensitive and culture techniques are time consuming. Hence, a new rapid technique in vitro Proton Magnetic Resonance Spectroscopy (¹HMRS) was evaluated for its usefulness in the identification of aetiology of brain abscesses. Materials and Methods: A total of 39 pus specimens from brain abscesses were subjected to in vitro ¹HMRS. These pus specimens were also processed by conventional culture methods. The spectral patterns generated by in vitro ¹HMRS were further correlated with culture results. Results: Pus specimens which showed the presence of anaerobes on culture revealed the presence of multiplet at 0.9 ppm (100%), lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (100%) and succinate at 2.4 ppm (75%). Pus specimens that revealed the presence of facultative anaerobes on culture showed a pattern B, i.e., the presence of lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (88.88%) along with the multiplet at 0.9 ppm (100%). Pattern C was seen in aerobic infection which showed the presence of lactate-lipid at 1.3 ppm (100%) along with the multiplet at 0.9 ppm. Pus from two tuberculous abscesses showed the complete absence of multiplet at 0.9 ppm. Conclusions: We observed in this study that it was possible to differentiate bacterial and tuberculous brain abscesses using in vitro ¹HMRS. Further, it was also possible to distinguish between aerobic and anaerobic brain abscesses on the basis of spectral patterns. In vitro ¹HMRS of fungal and actinomycotic brain abscess are also presented for its unusual spectra.