Preparation and properties of invertase immobilized on a poly(maleic anhydride-hexen-1) membrane

Poly(maleic anhydride-alt-hexen-1)(poly(MA-alt-H-1)) has been synthesized by radical polymerization and characterized by DSC, FT-IR, acid number determination, viscometric and NMR methods. Data showed that the co-polymer is an alternating co-polymer whose composition does not depend on the monomer feed composition. Invertase was immobilized onto a poly(MA-alt-H-1) membrane via glutaraldehyde and bovine serum albumin. The Km value of poly(MA-alt-H-1)-invertase was approximately 4.4-fold higher than the free enzyme, indicating decreased affinity by the invertase for its substrate (sucrose), whereas Vmax was lower for the immobilized invertase. Immobilization improved the pH stability of the enzyme, as well as its temperature stability. Immobilized samples obtained were stable and could be used many times over a period of 2 months without considerable activity loss.     

Neural mechanisms of swallowing and effects of taste and other stimuli on swallow initiation

Swallowing involves several motor processes such as bolus formation and intraoral transport of a food bolus (oral stage) and a series of visceral events that occur in a relatively fixed timed sequence but are to some degree modifiable (pharyngeal stage or swallow reflex). Reflecting the progressive aging of society, patients with swallowing disorders (i.e., dysphagia) are increasing. Therefore, there is expanding social demand for the development of better rehabilitation treatment of dysphagic patients. To date, many dysphagia diets have been developed and are available commercially to help bring back the pleasure of mealtimes to dysphagia patients. Texture modification of food to make the food bolus easier to swallow with less risk of aspiration is one of the important elements in dysphagia diets from the viewpoint of safety assurance. However, for the further development of dysphagia diets, new attempts based on new concepts are needed. One of the possible approaches is to develop dysphagia diets that facilitate swallow initiation. For this approach, an understanding of the mechanisms of swallow initiation and identification of factors that facilitate or suppress swallow initiation are important. In this review, we first summarize the neural mechanisms of swallowing and effects of taste and other inputs on swallow initiation based on data mainly obtained from experimental animals. Then we introduce a recently established technique for eliciting swallowing using electrical stimulation in humans and our ongoing studies using this technique.     

Dense IgG4 plasma cell infiltrates associated with chronic infectious aortitis: implications for the diagnosis of IgG4-related disease

BackgroundIgG4-related aortitis is a newly recognized form of noninfectious aortitis that occurs as part of the spectrum of a systemic disease referred to as IgG4-related disease. IgG4-related aortitis is distinguished from giant cell aortitis and Takayasu aortitis in part by the presence of increased numbers of IgG4-expressing plasma cells. Chronic infectious aortitis can also display lymphoplasmacytic infiltrates, but the degree of IgG4 expression in these cases has not been specifically evaluated.MethodsTwo cases of chronic active infectious abdominal aortitis were prospectively identified. Both were due to gram-positive bacteria, and at least one of the cases was due to chronic active Staphylococcus aureus infection. The degree of IgG4 plasma cell infiltration was assessed by immunohistochemistry.ResultsBoth cases of chronic infectious aortitis focally displayed high levels of IgG4-expressing plasma cells, greater than 50% of the IgG-expressing plasma cells, and greater than 50 IgG4-expressing plasma cells per high-power field.ConclusionsFocal dense IgG4 plasma cell infiltrates can be seen in association with chronic infectious aortitis due to gram-positive bacteria, including Staphylococcus aureus. This observation supports the proposal that chronic Staphylococcus aureus infection may stimulate a Th2-mediated elevation in IgG4. The pathologic diagnosis of IgG4-related aortitis should not be based solely on the presence of increased IgG4 plasma cell counts from immunohistochemistry, but requires consideration of the overall pathology, including careful exclusion of infectious aortitis.     

Sacculo-ocular reflex connectivity in cats

The otolith system contributes to the vestibulo-ocular reflexes (VOR) when the head moves linearly in the horizontal plane or tilts relative to gravity. The saccules are thought to detect predominantly accelerations along the gravity vector. Otolith-induced vertical eye movements following vertical linear accelerations are attributed to the saccules. However, information on the neural circuits of the sacculo-ocular system is limited, and the effects of saccular inputs on extraocular motoneurons remain unclear. In the present study, synaptic responses to saccular-nerve stimulation were recorded intracellularly from identified motoneurons of all twelve extraocular muscles. Experiments were successfully performed in eleven cats. Individual motoneurons of the twelve extraocular muscles--the bilateral superior recti (SR), inferior recti (IR), superior obliques (SO), inferior obliques (IO), lateral recti (LR), and medial recti (MR) were identified antidromically following bipolar stimulation of their respective nerves. The saccular nerve was selectively stimulated by a pair of tungsten electrodes after removing the utricular nerve and the ampullary nerves of the semicircular canals. Stimulus intensities were determined from the stimulus-response curves of vestibular N1 field potentials in order to avoid current spread. Intracellular recordings were performed from 129 extraocular motoneurons. The majority of the neurons showed no response to saccular-nerve stimulation. In 17 (30%) of 56 extraocular motoneurons related to vertical eye movements (bilateral SR and IR), depolarizing and/or hyperpolarizing postsynaptic potentials (PSPs) were observed in response to saccular-nerve stimulation. The latencies of PSPs ranged from 2.3 to 8.9 ms, indicating that the extraocular motoneurons received neither monosynaptic nor disynaptic inputs from saccular afferents. The majority of the latencies of the depolarization, including depolarization-hyperpolarization, were in the range of 2.3-3.3 ms. Latencies of hyperpolarizations were typically longer than those of depolarizations. Only one contralateral SO motoneuron of 43 recorded oblique extraocular motoneurons (bilateral SO and IO) showed a depolarization-hyperpolarization in response to saccular-nerve stimulation at a latency of 2.5 ms. None of 30 recorded horizontal extraocular motoneurons (bilateral LR and MR) responded to stimulation of the saccular nerve. The neural linkage in the sacculo-ocular system is relatively weak in comparison to the utriculo-ocular and sacculo-collic systems, suggesting that the role of the sacculo-ocular system in stabilizing eye position may be reduced when compared with utriculo-ocular and semi-circular canal-ocular reflexes.     

Open source drug discovery--a new paradigm of collaborative research in tuberculosis drug development

It is being realized that the traditional closed-door and market driven approaches for drug discovery may not be the best suited model for the diseases of the developing world such as tuberculosis and malaria, because most patients suffering from these diseases have poor paying capacity. To ensure that new drugs are created for patients suffering from these diseases, it is necessary to formulate an alternate paradigm of drug discovery process. The current model constrained by limitations for collaboration and for sharing of resources with confidentiality hampers the opportunities for bringing expertise from diverse fields. These limitations hinder the possibilities of lowering the cost of drug discovery. The Open Source Drug Discovery project initiated by Council of Scientific and Industrial Research, India has adopted an open source model to power wide participation across geographical borders. Open Source Drug Discovery emphasizes integrative science through collaboration, open-sharing, taking up multi-faceted approaches and accruing benefits from advances on different fronts of new drug discovery. Because the open source model is based on community participation, it has the potential to self-sustain continuous development by generating a storehouse of alternatives towards continued pursuit for new drug discovery. Since the inventions are community generated, the new chemical entities developed by Open Source Drug Discovery will be taken up for clinical trial in a non-exclusive manner by participation of multiple companies with majority funding from Open Source Drug Discovery. This will ensure availability of drugs through a lower cost community driven drug discovery process for diseases afflicting people with poor paying capacity. Hopefully what LINUX the World Wide Web have done for the information technology, Open Source Drug Discovery will do for drug discovery.     

Acute epiglottitis: a retrospective review of 47 patients in Kuwait

Objectives

Acute epiglottitis is a potentially life threatening condition which can lead to fatal airway obstruction in previously healthy individuals. The present study was undertaken to assess the clinical features, management and patient outcomes of epiglottitis in Kuwait over an eight year period.

Design

Case series.

Setting

Al Sabah Hospital, Kuwait.

Methods

All patients admitted to the ENT department of Al Sabah hospital between January 2000 and January 2008 with the diagnosis of acute epiglottitis were included in this retrospective study. The diagnosis of acute epiglottitis was established by visualization of inflamed epiglottis either on indirect laryngoscopy or flexible fibreoptic/direct laryngoscopy.

Results

47 cases were identified, 5 children and 42 adults. There were 32 males and 15 females, in the age range of 5 to 66 years. Peak incidence was in the third decade. 31 patients had co-morbid conditions, 18 patients (38.2%) had diabetes, 8 patients (17%) had hypertension and 3 patients (6.3%) had dental caries. Majority of the patients (89.3%) presented with sore throat as their chief complaint. All patients were febrile on presentation. The classical “thumb sign” on lateral neck radiograph was seen in 32 patients (68%). Blood cultures were collected from 22 patients (46.8%), all were negative. Ceftriaxone was the commonest empirical antibiotic prescribed. 7 patients required airway intervention (5 with endotracheal intubation and 2 with tracheostomy). There were no deaths in our study.

Conclusion

In Kuwait, acute epiglottis is commoner in adults than in children. It is imperative to secure the airway and to start the patients on broad spectrum antibiotics and steroids as early as possible. In general, the prognosis is good with antimicrobial therapy, close monitoring and selective airway intervention, in the form of intubation / tracheostomy, for patients with stridor or shortness of breath.     

Serum cortisol and testosterone levels in idiopathic central serous chorioretinopathy

Context:

The preferential occurrence of idiopathic central serous chorioretinopathy (ICSC) in males with a typical Type A personality and behavior and a relative absence in females is a possible indicator towards the role of serum cortisol and /or the male sex hormone testosterone.

Aims:

To study levels of cortisol and testosterone in ICSC.

Settings and Design:

Case-control study in a tertiary care teaching hospital.

Materials and Methods:

The study was conducted on 23 cases of ICSC. Twelve patients with unilateral sudden painless loss of vision of less than one month duration served as controls. Serum cortisol and testosterone levels at 8.00 a.m. were estimated by radioimmunoassay in both groups.

Statistical analysis used:

Statistical analysis was done using SPSS 13.0 software. Independent Sample t-test was applied to analyze statistical significance between the two groups.

Results:

Mean age of patients with ICSC was 37.1 ± 9.7 years and 96% of the patients were males. Mean serum cortisol levels were significantly higher (P=0.002) in patients with ICSC i.e., 495.02 ± 169.47 nano moles/liter (nmol/L) as compared to controls i.e., 362.25 ± 51.54 nmol/L. Mean serum testosterone levels were 3.85 ± 1.81 nano grams/ml (ngm/ml) and 4.23 ± 1.89 ngm/ml in cases and controls respectively and the difference was not statistically significant (P=0.58).

Conclusions:

ICSC is associated with elevated 8.00 a.m. serum cortisol levels. However, mean serum testosterone levels in both patients of ICSC and controls were within normal range.     

Solitary plasmocytoma of frontal bone presenting as an asymptomatic forehead lump

Solitary plasmocytoma of bone is a rare type of plasma cell tumor. We present a case of a solitary extramedullary plasmacytoma of the frontal bone presenting as an asymptomatic forehead lump with clinically benign characteristics. This case highlights the need for a high index of suspicion when dealing with enlarging subcutaneous lumps of the forehead and scalp. The significance of this lies in the appropriate sequencing of investigations and the implementation of the necessary treatment regimen.