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Biomedical subjects

K S Babu

Publications and source records attributed to K S Babu.

At least 19 recordsLinked to original sources
PubMed2006

Postsphaleron baryogenesis.

We present a new mechanism for generating the baryon asymmetry of the Universe directly in the decay of a singlet scalar field S(r) with a weak scale mass and a high dimensional baryon number-violating coupling. Unlike most currently popular models, this mechanism, which becomes effective after the electroweak phase transition, does not rely on the sphalerons for inducing a nonzero baryon number. CP asymmetry in S(r) decay arises through loop diagrams involving the exchange of W+/- gauge bosons and is suppressed by light quark masses, leading naturally to a value of eta(B) approximately 10(-10). The simplest realization of this idea which uses a six quark DeltaB=2 operator predicts colored scalars accessible to the CERN Large Hadron Collider and neutron-antineutron oscillation within reach of the next-generation experiments.

Journal Article↗
PubMed2005

Tumour necrosis factor (TNFalpha) as a novel therapeutic target in symptomatic corticosteroid dependent asthma.

BACKGROUND: Tumour necrosis factor alpha (TNFalpha) is a major therapeutic target in a range of chronic inflammatory disorders characterised by a Th1 type immune response in which TNFalpha is generated in excess. By contrast, asthma is regarded as a Th2 type disorder, especially when associated with atopy. However, as asthma becomes more severe and chronic, it adopts additional characteristics including corticosteroid refractoriness and involvement of neutrophils suggestive of an altered inflammatory profile towards a Th1 type response, incriminating cytokines such as TNFalpha. METHODS: TNFalpha levels in bronchoalveolar lavage (BAL) fluid of 26 healthy controls, 42 subjects with mild asthma and 20 with severe asthma were measured by immunoassay, and TNFalpha gene expression was determined in endobronchial biopsy specimens from 14 patients with mild asthma and 14 with severe asthma. The cellular localisation of TNFalpha was assessed by immunohistochemistry. An open label uncontrolled clinical study was then undertaken in 17 subjects with severe asthma to evaluate the effect of 12 weeks of treatment with the soluble TNFalpha receptor-IgG1Fc fusion protein, etanercept. RESULTS: TNFalpha levels in BAL fluid, TNFalpha gene expression and TNFalpha immunoreative cells were increased in subjects with severe corticosteroid dependent asthma. Etanercept treatment was associated with improvement in asthma symptoms, lung function, and bronchial hyperresponsiveness. CONCLUSIONS: These findings may be of clinical significance in identifying TNFalpha as a new therapeutic target in subjects with severe asthma. The effects of anti-TNF treatment now require confirmation in placebo controlled studies.

Adult↗
PubMed2003

Inhaled synthetic surfactant abolishes the early allergen-induced response in asthma.

Allergen-induced inhibition of pulmonary surfactant in asthma may promote airway oedema and consequently potentiate the severity of the asthmatic response. A randomised, single-blind, cross-over study of an inhaled synthetic phospholipid dry-powder surfactant (Pumactant) was conducted in atopic, asthmatic subjects with previously documented early and late asthmatic responses (EAR and LAR) to an inhaled allergen. This was conducted to evaluate the role of exogenous surfactant administration on EAR and LAR. A total of seven subjects had complete evaluable data and received the full dose of Pumactant. Asthmatic subjects inhaled two separate doses of 400 mg Pumactant prior to an allergen exposure. The first dose was administered 8 h in advance and the second dose 30 min in advance. The dosage occurred through a purpose-built administration device. This was followed by a standard bronchial-provocation test, and forced expiratory volume in one second (FEV1) was measured at regular intervals over a 10-h period. Pumactant was well tolerated and, surprisingly, abolished the EAR but not the LAR in all seven subjects. The mean area under the curve between 0-2 h (EAR) following bronchial provocation test was 0.08 for the Pumactant treatment group (PT) and 13.29 for the no treatment (NT) group. The maximum drop in FEV1 for EAR was 4.19% and 23.98% in the PT and the NT group, respectively. The demonstration of inhibition of the early asthmatic response by exogenous surfactant, provides the first evidence that pulmonary surfactant dysfunction may also contribute to the very early asthmatic response to allergen. Exogenous surfactant administration could serve as a useful adjunct in controlling the early allergen-induced symptoms in patients with allergic asthma.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2002

Higgs-mediated tau-->3micro in the supersymmetric seesaw model.

Recent observations of neutrino oscillations imply nonzero neutrino masses and lepton flavor violation (LFV), most economically explained by the seesaw mechanism. Within the context of supersymmetry, LFV among the neutrinos can be communicated to the sleptons and from there to the charged leptons. We show that LFV can appear in the couplings of the neutral Higgs bosons, an effect that is strongly enhanced at large tan(beta. We calculate the branching fraction for tau-->3micro and micro-->3e mediated by Higgs and find they can be as large as 10(-7) and 5x10(-14), respectively. These modes, along with tau-->mugamma and mu-->egamma, can provide key insights into the neutrino mass matrix.

Journal Article↗
PubMed2002

Management of cutaneous drug reactions.

Drugs are potent chemicals that often have effects in the body beyond the desired action. These effects may range from mild and expected side effects to dramatic and life-threatening anaphylaxis. Adverse drug reactions account for between 2% and 6% of hospital admissions and may prevent administration of otherwise effective therapeutic agents. Cutaneous and mucocutaneous eruptions are the most common adverse reactions to oral or parenteral drug therapy, and the spectrum ranges from transitory exanthematous rash to the potentially fatal toxic epidermal necrolysis. Different mechanisms, including both immunologic and nonimmunologic, are responsible for cutaneous adverse drug reaction. The treatment of cutaneous drug eruptions essentially rests on accurate history, a thorough physical examination, discontinuation of the offending drug, and supportive care. The management of a cutaneous drug eruption is very much individualized, based on the clinical setting. This review aims to provide a general approach to the patient with a presumed cutaneous drug reaction.

Drug Eruptions↗
PubMed2001

Omalizumab, a novel anti-IgE therapy in allergic disorders.

The incidence of allergic diseases is increasing to epidemic proportions both in the developed and developing world with increasing medical costs and lost productivity. The discovery of immunoglobulin (Ig) E heralded a new era in pathophysiological understanding of allergic disorders. Twenty-five years later, a humanised, non-anaphylactogenic antibody was developed against IgE that could provide a therapeutic alternative to the existing medications. RhuMAb-E25 (omalizumab, Xolair, Genetech, Inc.) is a novel anti-IgE antibody that is directed against the receptor-binding domain of IgE. This binding is specific towards free IgE thereby preventing it from attaching to the mast cell and its subsequent activation. Initial studies demonstrated attenuation of the early and late asthmatic responses when anti-IgE was administered to asthmatic subjects. Later this novel molecule was found to improve symptom scores, rescue medication use, quality of life scores and peak expiratory flows in patients with allergic asthma. Most importantly, omalizumab treatment reduced the corticosteroid use in asthmatic individuals. In patients with seasonal allergic rhinitis, there was a significant reduction in the nasal and ocular symptoms as well as the use of rescue medications. Omalizumab also demonstrated a high level of safety in adults, adolescents and children with a side effect profile no different from the placebo. Its development is an exciting milestone in the treatment of allergic diseases.

Antibodies, Anti-Idiotypic↗
PubMed2001

Quantitative study of muscle spindles in suboccipital muscles of human foetuses.

The proprioceptive inputs from the cervical musculature play an important role in head-eye co-ordination and postural processes. Deep cervical muscles in humans are shown to have high spindle content. The density, distribution and morphology of muscle spindles were studied in superior oblique capitis, inferior oblique capitis and rectus capitis posterior major and minor three small suboccipital muscles. The muscles were obtained, post-mortem from stillborn human foetus. The spindle density was calculated as the ratio of mean spindle content to the mean wet weight of that muscle in grams. The distribution and arrangement of spindles within the muscle and their arrangement was studied. The spindle density of superior oblique muscle was found to be 190, that of inferior oblique was 242 and the rectus capitis posterior contained 98 spindles per gram of muscle. No tendon organs were seen. The serial transverse sections of inferior oblique muscle revealed muscle spindles of varying sizes, length varying between 100-650 microns and, diameter 50-250 microns. A complex parallel arrangements of group of large spindles were seen in the belly of the inferior oblique muscle, while the polar regions contain few small isolated spindles. The relevance of such high spindle receptor content in these tiny muscles is discussed.

Fetus↗
PubMed2000

Aspirin and asthma.

Aspirin is not only one of the best-documented medicines in the world, but also one of the most frequently used drugs of all times. In addition to its role as an analgesic, aspirin is being increasingly used in the prophylaxis of ischemic heart disease and strokes. The prevalence of aspirin intolerance is around 5 to 6%. Up to 20% of the asthmatic population is sensitive to aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and present with a triad of rhinitis, sinusitis, and asthma when exposed to the offending drugs. This syndrome is referred to as aspirin-induced asthma (AIA). The pathogenesis of AIA has implicated both the lipoxygenase (LO) and the cyclooxygenase (COX) pathways. By inhibiting the COX pathway, aspirin diverts arachidonic acid metabolites to the LO pathway. This also leads to a decrease in the levels of prostaglandin (PG) E(2), the anti-inflammatory PG, along with an increase in the synthesis of cysteinyl leukotrienes (LTs). Evidence suggests that patients with AIA have increased activity of LTC(4) synthase, the rate-limiting enzyme in the cysteinyl LT synthesis, in their bronchial biopsy specimens, thereby tilting the balance in favor of inflammation. LT-modifying drugs are effective in blocking the bronchoconstriction provoked by aspirin and are used in the treatment of this condition. Aspirin desensitization has a role in the management of AIA, especially in patients who need prophylaxis from thromboembolic diseases, myocardial infarction, and stroke. This review covers the latest understanding of pathogenesis, clinical features, and management of AIA.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Potential and novel therapies for asthma.

Asthma is a chronic inflammatory disorder characterised by airflow obstruction. The inflammatory process involves mast cells, antigen presenting cells, eosinophils, neutrophils, airway epithelial cells and TH2 lymphocytes. These cells produce a broad array of pro-inflammatory mediators and cytokines that lead to the pathophysiological changes seen in asthma. The improved understanding of this complex disease, the specific cells and the complex mediators has lead to newer insights into the efficacy of various novel and potential therapies. In this review, we discuss the pharmacological agents that interrupt the synthesis and action of leukotrienes, cytokine antagonism, monoclonal antibodies against IgEs, selective phosphodiesterase inhibitors, adenosine receptor ligands and immunomodulators to drive the inflammatory response towards a TH1 type and other possible specific targeted therapy for the management of asthma. Although most of these therapies are in the inchoate stages these may hold the future for use in asthma.

Anti-Asthmatic Agents↗
PubMed1997

Reliability of somatosensory evoked potentials in intraoperative localization of the central sulcus in patients with perirolandic mass lesions.

Patients with parenchymatous mass lesions in the perirolandic area as seen by CT or MRI are unique in that identification of the central sulcus (CS) intraoperatively is crucial in determining the surgical strategy. Somatosensory-evoked potential (SEP) responses were used under general anaesthesia for the intraoperative identification of the central sulcus (CS). Sixty-five patients with parenchymatous mass lesions were included in the study and a phase reversal in the hand area across the central sulcus was used to identify this sulcus. Based on the clinical findings the patients were classified into three groups: Group A were patients with predominant motor deficits, Group B, patients with predominant sensory deficits; and Group C were patients with gross sensory and motor deficits. This study shows that in patients with predominant motor deficits a phase reversal with good amplitude was obtained in all cases. In patients with predominant sensory deficits a phase reversal could be obtained, but their amplitudes were markedly decreased. In patients with predominant sensorimotor deficits no phase reversal could be obtained. The central sulcus could not be located accurately by somatosensory evoked potentials in these cases (group C).

Adult↗
PubMed1996

Effect of low-intensity millimeter wave electromagnetic radiation on regeneration of the sciatic nerve in rats.

The effect of low-intensity millimeter wave electromagnetic radiation (MWR) on regeneration of the rat sciatic nerve after transection and microsurgical reapproximation was examined. Rats were exposed to 54 GHz MWR at a power density of 4 mW/cm2. It was found that MWR treatment of the femoral skin in the area of suture accelerated the regeneration of nerve fibers. At the twentieth postoperative day, the MWR-treated animals had a 32% increase in the regeneration distance compared to the control animals. The conduction velocity showed a 26% increase in the MWR-treated animals.

Animals↗
PubMed1996

Value of visual evoked potential monitoring during trans-sphenoidal pituitary surgery.

The visual outcome of 22 patients undergoing trans-sphenoidal excision of pituitary macroadenomas with intraoperative flash visual evoked potential (VEP) monitoring (Group A), was compared with a non-randomized group of 14 patients who had undergone similar operations without VEP monitoring (Group B). Tumour size, preoperative visual acuity, peripheral fields, and latencies and amplitudes of P1 and P2 were analysed to ascertain the best predictor of postoperative visual function. It was found that patients in Group A had a significantly greater improvement in field defects than those in Group B. There was no difference in postoperative improvement in visual acuity between the two groups. None of the variables analysed were good predictors of visual outcome.

Adenoma↗