Systemic lupus erythematosus presenting with holocord myelitis

This is a report of a case of a 25-year-old woman, who presented with a rapidly progressive sensory-motor flaccid quadriparesis which had developed over a few days along with bladder and bowel involvement. She had a past history of photosensitive rash and joint pains along with mild-to-moderate grade fever; for which she had never been evaluated. Serological markers for systemic lupus erythematosus (SLE) were strongly positive and helped in establishing the diagnosis of SLE-related holocord myelitis. High-dose intravenous glucocorticoid followed by intravenous pulse cyclophosphamide was used to treat her and there was a significant improvement. In this case report, the diagnosis of SLE was made for the first time in a patient presenting with holocord myelitis.

Cadmium versus Lanthanum Effects on Spontaneous Electrical Activity and Expression of Connexin Isoforms Cx26, Cx36, and Cx45 in the Human Fetal Cortex

Electrical activity is important for brain development. In brain slices, human subplate neurons exhibit spontaneous electrical activity that is highly sensitive to lanthanum. Based on the results of pharmacological experiments in human fetal tissue, we hypothesized that hemichannel-forming connexin (Cx) isoforms 26, 36, and 45 would be expressed on neurons in the subplate (SP) zone. RNA sequencing of dissected human cortical mantles at ages of 17-23 gestational weeks revealed that Cx45 has the highest expression, followed by Cx36 and Cx26. The levels of Cx and pannexin expression between male and female fetal cortices were not significantly different. Immunohistochemical analysis detected Cx45- and Cx26-expressing neurons in the upper segment of the SP zone. Cx45 was present on the cell bodies of human SP neurons, while Cx26 was found on both cell bodies and dendrites. Cx45, Cx36, and Cx26 were strongly expressed in the cortical plate, where newborn migrating neurons line up to form cortical layers. New information about the expression of 3 "neuronal" Cx isoforms in each cortical layer/zone (e.g., SP, cortical plate) and pharmacological data with cadmium and lanthanum may improve our understanding of the cellular mechanisms underlying neuronal development in human fetuses and potential vulnerabilities.

Stroke-related education to emergency department staff: An acute stroke care quality improvement initiative

Background

Acute ischemic stroke therapy is time sensitive, and optimum treatment is missed due to pre-hospital and/or in-hospital delay.

Materials and Methods

A prospective observational (before and after) study was conducted for 1 year.The study period was defined as phase-I or pre-education phase, phase-II or immediate post-education phase, and phase-III or delayed post-education phase, with each phase lasting for 4months. All consecutive stroke patients presenting within 12 hours of stroke onset were enrolled. Baseline and outcome data including acute stroke care quality matrices and functional outcomes were collected.

Results

A total of 264 patients were enrolled. All acute stroke care quality matrices improved significantly (P ≤ 0.01) with a median door to imaging time (DTI) of 114, 35, and 47 minutes in the three phases consecutively. In phase-II, proportions of patients imaged within 25 minutes of arrival increased by 35%. Mean door to needle (DTN) time were 142 ± 49.7,63.7 ± 25.1, and 83.9 ± 38.1 minutes in the three consecutive phases. Patients with DTN < 60 minutes of arrival increased by 63%. Modified Rankin score (mRS) at 3 months improved significantly in all ischemic stroke patients (P = 0.04) and patients with mRS of 0-2 increased by 22%.

Conclusions

Stroke education to emergency department (ED) staff is an effective method to improve acute stroke care.

Mechanisms of Spontaneous Electrical Activity in the Developing Cerebral Cortex-Mouse Subplate Zone

Subplate (SP) neurons exhibit spontaneous plateau depolarizations mediated by connexin hemichannels. Postnatal (P1-P6) mice show identical voltage pattern and drug-sensitivity as observed in slices from human fetal cortex; indicating that the mouse is a useful model for studying the cellular physiology of the developing neocortex. In mouse SP neurons, spontaneous plateau depolarizations were insensitive to blockers of: synaptic transmission (glutamatergic, GABAergic, or glycinergic), pannexins (probenecid), or calcium channels (mibefradil, verapamil, diltiazem); while highly sensitive to blockers of gap junctions (octanol), hemichannels (La3+, lindane, Gd3+), or glial metabolism (DLFC). Application of La3+ (100 μM) does not exert its effect on electrical activity by blocking calcium channels. Intracellular application of Gd3+ determined that Gd3+-sensitive pores (putative connexin hemichannels) reside on the membrane of SP neurons. Immunostaining of cortical sections (P1-P6) detected connexins 26, and 45 in neurons, but not connexins 32 and 36. Vimentin-positive glial cells were detected in the SP zone suggesting a potential physiological interaction between SP neurons and radial glia. SP spontaneous activity was reduced by blocking glial metabolism with DFLC or by blocking purinergic receptors by PPADS. Connexin hemichannels and ATP release from vimentin-positive glial cells may underlie spontaneous plateau depolarizations in the developing mammalian cortex.

Contribution of extrasynaptic N-methyl-D-aspartate and adenosine A1 receptors in the generation of dendritic glutamate-mediated plateau potentials

Thin basal dendrites can strongly influence neuronal output via generation of dendritic spikes. It was recently postulated that glial processes actively support dendritic spikes by either ceasing glutamate uptake or by actively releasing glutamate and adenosine triphosphate (ATP). We used calcium imaging to study the role of NR2C/D-containing N-methyl-d-aspartate (NMDA) receptors and adenosine A1 receptors in the generation of dendritic NMDA spikes and plateau potentials in basal dendrites of layer 5 pyramidal neurons in the mouse prefrontal cortex. We found that NR2C/D glutamate receptor subunits contribute to the amplitude of synaptically evoked NMDA spikes. Dendritic calcium signals associated with glutamate-evoked dendritic plateau potentials were significantly shortened upon application of the NR2C/D receptor antagonist PPDA, suggesting that NR2C/D receptors prolong the duration of calcium influx during dendritic spiking. In contrast to NR2C/D receptors, adenosine A1 receptors act to abbreviate dendritic and somatic signals via the activation of dendritic K(+) current. This current is characterized as a slow-activating outward-rectifying voltage- and adenosine-gated current, insensitive to 4-aminopyridine but sensitive to TEA. Our data support the hypothesis that the release of glutamate and ATP from neurons or glia contribute to initiation, maintenance and termination of local dendritic glutamate-mediated regenerative potentials.

Branch specific and spike-order specific action potential invasion in basal, oblique, and apical dendrites of cortical pyramidal neurons

In neocortical pyramidal neurons, action potentials (APs) propagate from the axon into the dendritic tree to influence distal synapses. Traditionally, AP backpropagation was studied in the thick apical trunk. Here, we used the principles of optical imaging developed by Cohen to investigate AP invasion into thin dendritic branches (basal, oblique, and tuft) of prefrontal cortical L5 pyramidal neurons. Multisite optical recordings from neighboring dendrites revealed a clear dichotomy between two seemingly equal dendritic branches belonging to the same cell ("sister branches"). We documented the variable efficacy of AP invasion in basal and oblique branches by revealing their AP voltage waveforms. Using fast multisite calcium imaging, we found that trains of APs are filtered differently between two apical tuft branches. Although one dendritic branch passes all spikes in an AP train, another branch belonging to the same neuron, same cortical layer, and same path distance from the cell body, experiences only one spike. Our data indicate that the vast differences in dendritic voltage and calcium transients, detected in dendrites of pyramidal neurons, arise from a nonuniform distribution of A-type [Formula: see text] conductance, an aggregate number of branch points in the path of the AP propagation and minute differences in dendritic diameter.

Spiny neurons of amygdala, striatum, and cortex use dendritic plateau potentials to detect network UP states

Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: (1) they are the most abundant cell type within their respective brain area, (2) covered by thousands of thorny protrusions (dendritic spines), (3) possess high levels of dendritic NMDA conductances, and (4) experience sustained somatic depolarizations in vivo and in vitro (UP states). In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (“dendritic UP states”) characterized by (i) fast rise, (ii) plateau phase lasting several hundred milliseconds, and (iii) abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates toward the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200–800 ms) steady depolarization (∼20 mV amplitude), which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states). We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states.

Study of the outcome of modified shoelace repair for midline incisional hernia

AIMS AND OBJECTIVES

To study the efficacy and short-term sequelae of modified shoelace repair for midline incisional hernias.

MATERIALS AND METHODS

A prospective non-randomized study of 30 cases of midline incisional hernias was carried out at a public hospital from May 2009 to Oct 2012. Patients underwent modified shoelace repair which comprises reconstruction of linea alba along with the use of polypropylene mesh to reinforce the facial layer. A proforma was maintained for each patient documenting patient details, nature of previous surgery and complications if any, postoperative course, and complications postincisional hernia repair.

RESULTS AND DISCUSSION

Thirty patients underwent this repair with no complications and no recurrence for minimum follow-up period of 12 months. Our technique is a simple extra-peritoneal procedure with no extensive tissue dissection and avoids the potential complications of bowel injury and adhesions with the mesh. The principle involved is that during straining, the recti shorten by tonic contraction and approximate toward the midline. An incisional hernia weakens the midline and causes the recti to move laterally with contraction as medial pull is lost. By reforming a strong new linea alba, there is restoration of medial pull on recti. This is further buttressed by the mesh.

CONCLUSION

Modified shoelace repair is a simple and safe extra-peritoneal procedure and can be used for all midline incisional hernias.

Neurogenic potential of hESC-derived human radial glia is amplified by human fetal cells

The efficient production of human neocortical neurons from human embryonic stem cells (hESC) is the primary requirement for studying early stages of human cortical development. We used hESC to obtain radial glial cells (hESC-RG) and then compared them with RG cells isolated from human fetal forebrain. Fate of hESC-RG cells critically depends on intrinsic and extrinsic factors. The expression of Pax6 (intrinsic factor) has a similar neurogenic effect on hESC-RG differentiation as reported for human fetal RG cells. Factors from the microenvironment also play a significant role in determining hESC-RG cell fate. In contrast to control cultures, wherein hESC-RG generate mainly astroglia and far fewer neurons, in co-cultures with human fetal forebrain cells, the reverse was found to be true. This neurogenic effect was partly due to soluble factors from human fetal brain cultures. The detected shift towards neurogenesis has significance for developing future efficient neuro-differentiation protocols. Importantly, we established that hESC-RG cells are similar in many respects to human fetal RG cells, including their proliferative capacity, neurogenic potential, and ability to generate various cortical neuronal sub-types. Unlike fetal RG cells, the hESC-RG cells are readily available and can be standardized, features that have considerable practical advantages in research and clinics.

Normobaric oxygen therapy in acute ischemic stroke: A pilot study in Indian patients

Purpose:

Clinical and radiological assessment of effects of normobaric high-flow oxygen therapy in patients with acute ischemic stroke (AIS).

Materials and Methods:

Patients with anterior circulation ischemic strokes presenting within 12 h of onset, ineligible for intravenous thrombolysis, an National Institute of Health Stroke Scale (NIHSS) score of >4, a mean transit time (MTT) lesion larger than diffusion-weighted image (DWI) (perfusiondiffusion mismatch), and an evidence of cortical hypoperfusion on magnetic resonance imaging (MRI) were included into the trial. Active chronic obstructive pulmonary disease (COPD), requirement of >3/L min oxygen delivery to maintain SaO2 > 95%, rapidly improving neurological deficits, pregnancy, contraindications to MRI, or unstable medical conditions were excluded. The experimental group received humidified oxygen at flow rates of 10 L/min for 12 h. The NIHSS, modified Rankin Score (mRS), Barthel Index (BI) were measured at 0, 1, 7 day of admission and at 3 months follow-up. MRI with DWI/PWI was performed at admission, 24 h later and at 3 months follow-up.

Results:

Of 40 patients (mean age = 55.8 years ± 13.2) (range, 26–82), 20 patients were randomized to normobaric oxygen (NBO). The mean NIHSS in NBO and control groups were 14.25 and 12.7 at admission which decreased to 11.6 and 9.5 on the seventh day, and 9.4 and 9.05 at 3 months, respectively. The mean mRS (3.7/3.7) and BI (58.2/53.9) in NBO and control groups improved to 2/2.2 and 73.05/73.8 at the end of 3 months, respectively.

Conclusions:

NBO did not improve the clinical scores of stroke outcome in Indian patients with AIS.

Epilepsy surgery in a pediatric population: a retrospective study of 129 children from a tertiary care hospital in a developing country along with assessment of quality of life

PURPOSE

To assess the outcome of a pediatric population operated for drug-resistant epilepsy from a large tertiary care center in India.

METHODS

Retrospectively: quality of life (QOL); prospectively: preoperative assessment included interictal EEG, MRI (as per epilepsy protocol), video-EEG. Ictal SPECT (with subtraction) and PET were performed when required. QOL scores were assessed using the HASS or SSQ for seizure severity, Quality of Life in Childhood Epilepsy (QOLCE) for QOL, and Child Behavior Check List (CBCL) for behavior.

RESULTS

142 were operated from January 2000 to June 2011 by the senior author. 118 patients with at least 1 year of follow-up were included in the study. Mean age at surgery was 9.8 ± 4.3 years. In addition, 40 patients underwent QOL assessment prospectively both before and after surgery. Mean duration of epilepsy was 5.3 ± 3.3 years. A class I outcome (Engel's) was seen in 79.5% patients, class II in 8.6%, class III in 10.7%, and class IV in 1 patient. As per surgical procedures, class I outcome in patients who underwent temporal resection, hemispherotomy and extratemporal resection was 76, 87 and 72%, respectively. QOL scores correlated with duration of seizures, epileptic encephalopathy and outcome of surgery, but not with side of surgery, age and sex.

CONCLUSIONS

This study, the largest reported from India, has demonstrated satisfactory results for epilepsy surgery in children.

Electrophysiological characteristics of seizure clusters

The phenomenon of temporal clustering of seizures is well known, but its effect on seizure localization has not been rigorously analyzed. The aim of our study was to assess electrophysiological localization during Video EEG (VEEG) monitoring in patients with intractable epilepsy demonstrating a cluster of seizures. The study was conducted on 203 intractable epilepsy patients, aged 2 to 60 years (19.96 +/- 10.87). Patients with unilateral temporal lobe epilepsy having clusters were compared with patients not having clusters, and the effect of clustering on concordance was addressed. Fully consistent localization was observed in 116 patients, partially consistent localization in 18 patients, and inconsistent localization in 19 patients. ANOVA did not reveal any significant difference in these groups (p=0.65). A total of 770 seizures recorded from 149 patients was analyzed for clustering effect. Clustering was present in 603/770 seizures pairs (78.31%). In the cluster group, 483 (80.09%) seizure pairs were concordant for seizure onset, while 98 (16.25%) were discordant and 22 (3.65%) were indeterminate. In the noncluster group, 134 (80.24%) seizure pairs were concordant for seizure onset, while 23 (13.77%) were discordant and 10 (5.98%) were indeterminate. The study found that cluster seizures occurring within an interseizure interval (ISI) less than 8 hours are independent and have the same localizing value as those seizures with longer ISIs.

Surgery for medically intractable epilepsy due to postinfectious etiologies

Medically intractable epilepsy (MIE) resulting from postinfectious etiologies requiring surgery have been uncommonly reported. A series of 28 cases are presented (hospital prevalence 5.7%). The mean duration of epilepsy prior to surgery was 8.2 +/- 2.1 years. The mean time of onset of epilepsy after central nervous system infection was 1.4 +/- 0.9 years (range 0-19 years). The pathologies included postpyogenic meningitic/encephalitic sequel (8), neurocysticercosis (6), tuberculomas/posttuberculous etiology (4), postpyogenic abscess of otogenic etiology (4), posttraumatic abscess-related gliosis (2), and gliosis of unknown infectious etiology (4) cases. Surgery included mesial temporal (11), lateral temporal (4), frontal (9), parietal (2) resections and hemispherotomy (1). Hippocampal sclerosis was seen in nine cases (4 neurocysticercosis) and this occurred in younger persons as compared to neocortical epilepsies. Good outcome (Engel class I and II) was seen in 23 of 28 cases (Engel class I in 17).

Association of allergic patients' phenotypes with IgE reactivity to recombinant pollen marker allergens

BACKGROUND

During the last decade allergen molecules from several allergen sources have been produced by recombinant DNA technology. The aim of this study was to investigate whether IgE reactivity to recombinant pollen allergens with broad and narrow cross-reactivity is associated with clinical phenotypes of allergic sensitization.

METHODS

Serum IgE reactivity to a panel of six recombinant birch and grass pollen allergens was measured by ELISA in pollen sensitized patients from Central Europe to define groups of patients with exclusive IgE reactivity to rBet v 1, with exclusive reactivity to major grass pollen allergens (rPhl p 1, rPhl p 2, rPhl p 5) and with IgE reactivity to cross-reactive pollen allergens (rBet v 2, rPhl p 7). Patients' clinical phenotypes were recorded. IgE responses to tree, grass and weed pollen as well as plant food extracts were evaluated in vitro by CAP-FEIA and clinical sensitivities were confirmed in vivo by skin prick testing.

RESULTS

IgE reactivity to the recombinant major birch pollen allergen, rBet v 1, was associated with sensitization to pollen from birch, taxonomically related trees and to certain plant-derived food. Reactivity to the recombinant timothy grass pollen allergens, rPhl p 1, rPhl p 2, rPhl p 5, indicated sensitization to pollen from grasses. Patients reacting with the highly cross-reactive allergen rPhl p 7 were polysensitized to pollen from unrelated trees, grasses and weeds and rBet v 2-positive patients were polysensitized to pollen and plant-derived food from unrelated plants.

CONCLUSIONS

IgE reactivity to recombinant marker allergens is associated with clinical phenotypes of allergic sensitization and may be useful for the selection of treatment strategies.

Idiopathic hypertrophic cranial pachymeningitis and dural sinus occlusion: two patients with long-term follow up

Idiopathic hypertrophic cranial pachymeningitis (IHPM) is a clinicopathological entity characterized by thickening and fibrosis of the dura mater with resultant clinical symptoms. It is generally steroid responsive and has a tendency to remit and relapse. We present here two patients with IHPM with associated dural sinus occlusion and describe their clinicoradiological features and long-term course and outcome.

Corticosteroids for managing tuberculous meningitis

BACKGROUND

Tuberculous meningitis, a serious form of tuberculosis that affects the meninges covering the brain and spinal cord, is associated with high mortality and disability among survivors. Corticosteroids have been used as an adjunct to antituberculous drugs to improve the outcome, but their role is controversial.

OBJECTIVES

To evaluate the effects of corticosteroids as an adjunct to antituberculous treatment on death and severe disability in people with tuberculous meningitis.

SEARCH STRATEGY

In September 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, LILACS, and Current Controlled Trials. We also contacted researchers and organizations working in the field, and checked reference lists.

SELECTION CRITERIA

Randomized controlled trials comparing a corticosteroid plus antituberculous treatment with antituberculous treatment alone in people with clinically diagnosed tuberculosis meningitis and which include death and/or disability as outcome measures.

DATA COLLECTION AND ANALYSIS

We independently assessed search results and methodological quality, and independently extracted data. We analysed the data using relative risks (RR) with 95% confidence intervals (CI) and the fixed-effect model. We also conducted complete-case and best-worst case analyses.

MAIN RESULTS

Seven trials involving 1140 participants (with 411 deaths) met the inclusion criteria. All used dexamethasone or prednisolone. Overall, corticosteroids reduced the risk of death (RR 0.78, 95% CI 0.67 to 0.91; 1140 participants, 7 trials). Data on disabling residual neurological deficit from three trials showed that corticosteroids reduce the risk of death or disabling residual neurological deficit (RR 0.82, 95% CI 0.70 to 0.97; 720 participants, 3 trials). Adverse events included gastrointestinal bleeding, bacterial and fungal infections and hyperglycaemia, but they were mild and treatable.

AUTHORS' CONCLUSIONS

Corticosteroids should be routinely used in HIV-negative people with tuberculous meningitis to reduce death and disabling residual neurological deficit amongst survivors. However, there is not enough evidence to support or refute a similar conclusion for those who are HIV positive.

Hyperacute thrombolysis with IV rtPA of acute ischemic stroke: Efficacy and safety profile of 54 patients at a tertiary referral center in a developing country

BACKGROUND

Given the constraints of resources, thrombolysis for acute ischemic stroke (AIS) is under evaluation in developing countries. Prothrombin time (PT), platelet count and activated partial thromboplastin time (aPTT) may not be feasible within the time window.

AIM

To evaluate the safety and efficacy of thrombolysis in selected patients without the coagulation profile.

DESIGN

Open, nonrandomized, observational study.

MATERIALS AND METHODS

Fifty-four stroke patients were classified using TOAST criteria (large artery atherosclerotic = 13; cardioembolic = 12; small vessel occlusion = 22; other determined etiology =three; undetermined etiology = four). The mean time to reach emergency was 2.4h (1.15-3.4), the mean door to CT, 24 min (10-47) and the door to recombinant tissue plasminogen activator (r-tPA) injection, 26.8 min (25-67). The NIHSS scores ranged from 11 to 22 (mean = 15.5 +/- 2.7). Patients with history of liver or renal disease or those on anticoagulants were excluded. The PT, aPTT and platelet count were not done. Recombinant tissue plasminogen activator was administered at a dosage of 0.9 mg/Kg.

RESULTS

Thirty-five patients (65%) significantly improved on NIHSS at 48 h (> or =4 points) (mean change = 10; range= 4-17). At one month, 43 (79%) improved on Barthel Index (mean change = 45%). One each developed small frontal lobe hemorrhage and recurrent stroke; one died of aspiration; and eight showed no improvement.

CONCLUSIONS

Hyperacute thrombolysis was found useful and safe in selected patients with AIS even without the coagulation studies.

Dengue fever with papilledema: a case of dengue-3 virus infection in central nervous system

BACKGROUND AND OBJECTIVES

Neurological manifestations of dengue fever are rarely reported during acute illness and clinical presentation commonly observed is of acute encephalitis or one of the post-infectious immune mediated manifestations. We describe a case of dengue fever having mild encephalopathy and papilledema at presentation.

CASE REPORT

Twenty-year-old female presented with fever, headache and vomiting. On examination she did not have classical signs of dengue fever and was found to have bilateral papilledema on fundus examination. Detailed work-up did not reveal any other cause of papilledema. Diagnosis of dengue fever was established by blood IgM antibody test on day 7 of illness. Retrospective analysis of CSF (drawn on day 5 of illness) by RT-PCR assay showed a characteristic band of dengue-3 virus. Papilledema was transient and subsided following symptomatic treatment. The patient recovered from acute illness and follow-up was unremarkable.

CONCLUSION

Especially in dengue endemic areas, in the patients having acute febrile illness with subtle signs and symptoms suggestive of CNS involvement, dengue virus infection should also be ruled out early in the clinical course.

A study of nonepileptic seizures in an Indian population

OBJECTIVE

The goal of this study was to evaluate the background and the clinical profile of nonepileptic seizures (NESs) confirmed by short-term video encephalography (ST-VEEG) recording in an Indian population.

METHODS

Seventy-one patients with NESs were enrolled. A complete history was taken and the recorded event was reviewed to define the ictal events. Patients were divided into two groups, Group 1 with a paucity of movements and Group 2 with an excess of movement, and results were analyzed.

RESULTS

The mean age was 22.9 (9.6); there were 15 males (21.1%) and 56 females (78.9%). Twenty-four patients (33.8%) were receiving antiepileptic drugs. The majority of the patients (42, 59.1%) were students. All patients were amnesic for the event and were unresponsive during the event. The other characteristics were similar events in 98.6%, hyperventilation in 58 (81.7%). Forty-two patients (59.2%) were in Group 1 and 29 patients (40.8%) were in Group 2.

CONCLUSION

NES is a disease of the young and can affect the student or professional. A wrong diagnosis can result in inappropriate treatment. Awareness of this entity is critical to ensuring prompt diagnosis and early intervention.

Landau Kleffner syndrome: electroclinical and etiopathogenic heterogeneity

Landau - Kleffner syndrome is a rare, functional, age-related epilepsy with aphasia and epileptiform discharges on EEG. The heterogenity of clinical presentations, course, long-term outcome and response to treatment suggests multiple underlying etiologies. Normal children abruptly develop deterioration of language functions along with spike and wave discharges on EEG. Clinical seizures may or may not be present. The aphasia responds poorly to most drugs. Valproic acid and benzodiazepines are most effective. Steroids and intravenous immunoglobulins have shown a variable response. Long-term outcome of aphasia is variable, many patients persist with residual impairment. Important questions regarding etiopathogenesis are unanswered.

Molecular mechanisms of DNA damage and repair: progress in plants

Despite stable genomes of all living organisms, they are subject to damage by chemical and physical agents in the environment (e.g., UV and ionizing. radiations, chemical mutagens, fungal and bacterial toxins, etc.) and by free radicals or alkylating agents endogenously generated in metabolism. DNA is also damaged because of errors during its replication. The DNA lesions produced by these damaging agents could be altered base, missing base, mismatch base, deletion or insertion, linked pyrimidines, strand breaks, intra- and inter-strand cross-links. These DNA lesions could be genotoxic or cytotoxic to the cell. Plants are most affected by the UV-B radiation of sunlight, which penetrates and damages their genome by inducing oxidative damage (pyrimidine hydrates) and cross-links (both DNA protein and DNA-DNA) that are responsible for retarding the growth and development. The DNA lesions can be removed by repair, replaced by recombination, or retained, leading to genome instability or mutations or carcinogenesis or cell death. Mostly organisms respond to genome damage by activating a DNA damage response pathway that regulates cell-cycle arrest, apoptosis, and DNA repair pathways. To prevent the harmful effect of DNA damage and maintain the genome integrity, all organisms have developed various strategies to either reverse, excise, or tolerate the persistence of DNA damage products by generating a network of DNA repair mechanisms. A variety of different DNA repair pathways have been reported that include direct reversal, base excision repair, nucleotide excision repair, photoreactivation, bypass, double-strand break repair pathway, and mismatch repair pathway. The direct reversal and photoreactivation require single protein, all the rest of the repair mechanisms utilize multiple proteins to remove or repair the lesions. The base excision repair pathway eliminates single damaged base, while nucleotide excision repair excises a patch of 25- to 32-nucleotide-long oligomer, including the damage. The double-strand break repair utilizes either homologous recombination or nonhomologous endjoining. In plant the latter pathway is more error prone than in other eukaryotes, which could be an important driving force in plant genome evolution. The Arabidopsis genome data indicated that the DNA repair is highly conserved between plants and mammals than within the animal kingdom, perhaps reflecting common factors such as DNA methylation. This review describes all the possible mechanisms of DNA damage and repair in general and an up to date progress in plants. In addition, various types of DNA damage products, free radical production, lipid peroxidation, role of ozone, dessication damage of plant seed, DNA integrity in pollen, and the role of DNA helicases in damage and repair and the repair genes in Arabidopsis genome are also covered in this review.

Identification of pronp1, a tobacco profilin gene activated in tip-growing cells

In plant cells, several cellular processes depend on rapid reorganization of a dynamic network of actin cytoskeletal elements in response to internal and environmental stimuli. Profilins, ubiqitous eukaryotic actin monomer-binding proteins with highly conserved three-dimensional structures, regulate the actin cytoskeleton and are considered to link the microfilament system with signal transduction pathways. Plant profilins have been grouped into two distinct classes, gametophytic (pollen-specific) and sporophytic. Here we report the isolation of a profilin gene that seems to be activated during tip growth of specialized cells of gametophytic as well as sporophytic origin. Identification of a genomic DNA clone containing a tobacco profilin gene, pronp1, and analysis of the pronp1 promoter-uidA fusion gene in transgenic Nicotiana tabacum plants revealed a prominent expression of pronp1 in mature pollen and elongating pollen tubes and significant activity in root hairs of developing seedlings. This expression pattern was distinct from that of any other profilin gene isolated so far. Pronp1 thus represents a unique profilin gene that is activated at the transcriptional level in two kinds of tip-growing cells, pollen tubes and root hairs, both of which require rapid organization of the actin cytoskeleton. The isolation of such a gene has fundamental importance for our understanding of modulation of the actin cytoskeleton at the molecular level.

Biphasic illness pattern due to early relapse in Japanese-B virus encephalitis

Japanese-B virus encephalitis (JE) is considered a uniphasic illness with a variable outcome. Biphasic illness patterns have never been reported previously. From an endemic zone in India we observed six patients of JE (from 62 patients treated in 7 years) who had an early relapse resulting in the biphasic clinical course. Five had poor socio-economic status and three had laboratory evidence of nutritional deficiency. Two patients were adults and the other four were children. Fever, rigors, headaches, body aches, altered consciousness, rigidity and tremors predominated the first phase of illness. During the second phase, behavioural changes, dystonia, pen-oral dyskinesia, drooling, mutism and muscle wasting due to anterior horn cell involvement were the important features. Though the serial antibody titres against the JE virus showed a four-fold rise in the initial or late convalescent phases, there was no increase during the second phase of the illness as compared to the first phase. On MRI, fresh lesions appeared during the second phase at the sites known for their involvement in JE, suggesting recrudescence of the virus. One patient survived with major sequelae, two with minor sequelae and the other three had complete recovery. We conclude that some patients with JE may have an early relapse after partial recovery, giving rise to the biphasic illness pattern. A locally prevalent genetic variant of the virus or host factors may be responsible for the altered clinical course of the disease. Biphasic illness does not necessarily mean a bad prognosis.

Reduction in allergenicity of grass pollen by genetic engineering

BACKGROUND

Hay fever and allergic asthma triggered by grass pollen allergens affect approximately 20% of the population in cool temperate climates. Ryegrass is the dominant source of allergens due to its prodigious airborne pollen production. Lol p 5 or group 5 is among the most important and widespread grass pollen allergen because it reacts with IgE antibodies of more than 90% of grass pollen-allergic patients, contains most of the grass pollen-specific IgE epitopes and elicits strong biological responses. Significant efforts have been made in developing diagnostic and therapeutic reagents for designing new and more effective immunotherapeutic strategies for treatment of allergic diseases. An alternative approach to this problem could be to reduce the amount of allergen content in the source plant.

METHODS

High velocity microprojectile bombardment was used to genetically engineer ryegrass. Antisense construct targeted to one of major allergen, Lol p 5, was introduced. The expression of antisense RNA was regulated by a pollen-specific promoter. Pollen was analysed for IgE reactivity.

RESULTS

Analysis of proteins with allergen-specific monoclonal and polyclonal antibodies did not detect Lol p 5 in the transgenic pollen. The transgenic pollen showed remarkably reduced allergenicity as reflected by low IgE binding capacity of pollen extract as compared to control pollen. The transgenic ryegrass plants in which Lol p 5 gene expression is perturbed showed normal fertile pollen development.

CONCLUSIONS

Our studies showed that it is possible to selectively 'switch off' allergen production in pollen of ryegrass demonstrating feasibility of genetic engineering of plants for reduced allergenicity.

RAPD analysis of seed purity in a commercial hybrid cabbage (Brassica oleracea var. capitata) cultivar

The use of random amplified polymorphic DNA (RAPD) markers for evaluating seed purity in a commercial F1-hybrid cabbage (Brassica oleracea var. capitata) cultivar is demonstrated. Genomic DNA isolated from single ungerminated seed was found to be suitable for RAPD analysis. DNA from F1-hybrid and its parental lines was subjected to RAPD screening with 36 random decamer arbitrary primers. A total of 241 scorable products were observed with 54 (22%) being polymorphic. The RAPD data showed that the parental lines of this commercial cabbage cultivar were not very closely related. Two primers were chosen for purity testing of the F1-hybrid seeds. The sib (inbred seed; seed from self-pollination of parental lines) contamination results obtained by RAPD analysis were comparable to the commonly used grow-out trial and isozyme analysis, hence showing that RAPD analysis can be used for seed purity testing of commercial hybrid cabbage seeds.

Antisense-mediated silencing of a gene encoding a major ryegrass pollen allergen

Type 1 allergic reactions, such as hay fever and allergic asthma, triggered by grass pollen allergens are a global health problem that affects approximately 20% of the population in cool, temperate climates. Ryegrass is the dominant source of allergens because of its prodigious production of airborne pollen. Lol p 5 is the major allergenic protein of ryegrass pollen, judging from the fact that almost all of the individuals allergic to grass pollen show presence of serum IgE antibodies against this protein. Moreover, nearly two-thirds of the IgE reactivity of ryegrass pollen has been attributed to this protein. Therefore, it can be expected that down-regulation of Lol p 5 production can significantly reduce the allergic potential of ryegrass pollen. Here, we report down-regulation of Lol p 5 with an antisense construct targeted to the Lol p 5 gene in ryegrass. The expression of antisense RNA was regulated by a pollen-specific promoter. Immunoblot analysis of proteins with allergen-specific antibodies did not detect Lol p 5 in the transgenic pollen. The transgenic pollen showed remarkably reduced allergenicity as reflected by low IgE-binding capacity of pollen extract as compared with that of control pollen. The transgenic ryegrass plants in which Lol p 5 gene expression is perturbed showed normal fertile pollen development, indicating that genetic engineering of hypoallergenic grass plants is possible.

Genetically engineered plant allergens with reduced anaphylactic activity

Allergy immunotherapy is based on the administration of increasing amounts of the disease-eliciting allergens in order to yield allergen-specific non-responsiveness. Success of this therapy is associated with modulation of the immune response to allergenic molecules at the level of T-helper cells and the induction of blocking antibodies. The extracts used for immunotherapy are highly heterogenous preparations from natural sources and contain additional components, mostly proteins which are not well defined. Recombinant DNA technology offers novel tools for production of pure and well-characterised allergens for specific immunotherapy. However, high IgE reactivity of pure recombinant allergens is associated with an increased risk of potentially life-threatening anaphylactic reactions. A major improvement in allergen-specific immunotherapy may be achieved by using genetically engineered recombinant allergens with reduced anaphylactic activity. Recently the site- directed mutagenesis technique has been applied successfully to produce variants of major grass, birch and oilseed rape allergens with reduced IgE reactivity but retained T-cell reactivity. These modified allergens with reduced anaphylactic potential are novel candidates for safer and more effective allergen-specific immunotherapy.

Male gametic cell-specific gene expression in flowering plants

The role of the male gamete-the sperm cell-in the process of fertilization is to recognize, adhere to, and fuse with the female gamete. These highly specialized functions are expected to be controlled by activation of a unique set of genes. However, male gametic cells traditionally have been regarded as transcriptionally quiescent because of highly condensed chromatin and a very reduced amount of cytoplasm. Here, we provide evidence for male gamete-specific gene expression in flowering plants. We identified and characterized a gene, LGC1, which was shown to be expressed exclusively in the male gametic cells. The gene product of LGC1 was localized at the surface of male gametic cells, suggesting a possible role in sperm-egg interactions. These findings represent an important step toward defining the molecular mechanisms of male gamete development and the cellular processes involved in fertilization of flowering plants.

Male gametic cell-specific expression of H2A and H3 histone genes

Formation of the generative cell in flowering plants initiates the male spermatogenesis pathway which eventually culminates in the process of double fertilization. Little is known about the molecular mechanisms operative in the generative cell. Here, we report the isolation and characterization of cDNA clones encoding generative cell-specific histones, gcH2A and gcH3. In situ hybridization analysis revealed that both genes are activated after formation of the generative cell and accumulation of transcripts increases progressively during generative cell maturation. These results suggest that gcH2A and gcH3 mRNAs are products of transcriptional activation of the generative cell nucleus and thus provide the first evidence for male germ line cell-specific gene expression in flowering plants.

Isolation and collection of two populations of viable sperm cells from the pollen of Plumbago zeylanica

A protocol is described for individually collecting two populations of sperm cells, Svn and Sua, from pollen of Plumbago zeylanica. Pollen grains were burst in 10 mM MOPS buffer containing 0.8 M mannitol (pH 4.6). Paired sperm cells released from pollen were separated using a microinjector. Svn and Sua were then collected individually with a microinjector, based upon known size differences. Collected sperm cells were washed with isolation medium and transferred to liquid nitrogen until use. Fluorochromatic reaction (FCR) test of isolated sperm cells showed a positive reaction, indicating that the isolated sperm cells are viable; most of the sperm cells retain viability for at least 2 h.

Engineering of hypoallergenic mutants of the Brassica pollen allergen, Bra r 1, for immunotherapy

The Brassica pollen allergen Bra r 1 belongs to a new family of Ca2+-binding proteins, characterized by the presence of two potential EF-hand calcium-binding domains. Disruption of these EF-hand motifs by amino acid substitutions demonstrated that both domains of Bra r 1 constitute functional Ca2+-binding sites. Calcium-binding deficient mutants displayed significantly reduced IgE-binding activity. Injection of these mutated Bra r 1 variants into a murine model system showed that mouse IgG raised against the mutants recognized native Bra r 1 in Brassica pollen extracts suggesting the potential use of the engineered allergens for effective immunotherapy.

Genetic control of male fertility in Arabidopsis thaliana: structural analyses of postmeiotic developmental mutants

Seven new male-sterile mutants (ms7-ms13) of Arabidopsis thaliana (L.) Heynh. (ecotype columbia) are described that show a postmeiotic defect of microspore development. In ms9 mutants, microspores recently released from the tetrad appear irregular in shape and are often without exines. The earliest evidence of abnormality in ms12 mutants is degeneration of microspores that lack normal exine sculpturing, suggesting that the MS12 product is important in the formation of pollen exine. Teratomes (abnormally enlarged microsporocytes) are also occasionally present and each has a poorly developed exine. In ms7 mutant plants, the tapetal cytoplasm disintegrates at the late vacuolate microspore stage, apparently causing the degeneration of microspores and pollen grains. With ms8 mutants, the exine of the microspores appears similar to that of the wild type. However, intine development appears impaired and pollen grains rupture prior to maturity. In ms11 mutants, the first detectable abnormality appears at the mid to late vacuolate stage. The absence of fluorescence in the microspores and tapetal cells after staining with 4',6-diamidino-2-phenylindole (DAPI) and the occasional presence of teratomes indicate degradation of DNA. Viable pollen from ms10 mutant plants is dehisced from anthers but appears to have surface abnormalities affecting interaction with the stigma. Pollen only germinates in high-humidity conditions or during in-vitro germination experiments. Mutant plants also have bright-green stems, suggesting that ms10 belongs to the eceriferum (cer) class of mutants. However, ms10 and cer6 are non-allelic. The ms13 mutant has a similar phenotype to ms10, suggesting is also an eceriferum mutation. Each of these seven mutants had a greater number of flowers than congenic male-fertile plants. The non-allelic nature of these mutants and their different developmental end-points indicate that seven different genes important for the later stages of pollen development have been identified.

Molecular basis of IgE-recognition of Lol p 5, a major allergen of rye-grass pollen

Grass pollen, especially of rye-grass (Lolium perenne). represents an important cause of type I allergy. Identification of IgE-binding (allergenic) epitopes of major grass pollen allergens is essential for understanding the molecular basis of interaction between allergens and human IgE antibodies and therefore facilitates the devising of safer and more effective diagnostic and immunotherapy reagents. The aim of this study was to identify the allergenic epitopes of Lol p 5, a major allergen of rye-grass pollen, immunodissect these epitopes further so that the amino acid residues critical for antibody binding can be determined and investigate the conservation and nature of these epitopes within the context of the natural grass pollen allergens. Peptides, 12-13 amino acid residues long and overlapping each other by 4 amino acid residues, based on the entire deduced amino acid sequence of the coding region of Lol p 5, were synthesised and assayed for IgE-binding. Two strong IgE-binding epitopes (Lol p 5 (49-60) and (265-276), referred to as peptides 7 and 34, respectively) were identified. These epitopes were further resolved by truncated peptides and amino acid replacement studies and the amino acid residues critical for IgE-binding determined (Lol p 5 (49-60) residue Lys57 and (265-276) residue Lys275). Sequences of these epitopes were conserved in related allergens and may form the conserved allergenic domains responsible for the cross-reactivity observed between pollen allergens of taxonomically related grasses. Furthermore, due to its strong IgE-reactivity, synthetic peptide Lol p 5 (265-276) was used to affinity-purify specific IgE antibodies which recognised proteins of other clinically important grass pollens. further indicating presence of allergenic cross-reactivity at the level of allergenic epitope. Moreover, Lol p 5 (265 276) demonstrated a strong capacity to inhibit IgE-binding to natural rye-grass pollen proteins highlighting the antibody accessibility to these sequences within the context of the natural allergens. Strong IgE-binding epitopes of Lol p 5 have been identified down to single critical amino acid residues and are shown to occur as linear or continuous domains in the natural conformation of natural Lol p 5 and other group 5 grass pollen allergens. The fact that such an allergenic synthetic epitope has the capacity to strongly inhibit IgE-binding to natural allergens highlight its potential for use as a candidate in future therapeutics to treat pollen-associated allergies.

Plant homologue of human excision repair gene ERCC1 points to conservation of DNA repair mechanisms

Nucleotide excision repair (NER), a highly versatile DNA repair mechanism, is capable of removing various types of DNA damage including those induced by UV radiation and chemical mutagens. NER has been well characterized in yeast and mammalian systems but its presence in plants has not been reported. Here it is reported that a plant gene isolated from male germline cells of lily (Lilium longiflorum) shows a striking amino acid sequence similarity to the DNA excision repair proteins human ERCC1 and yeast RAD10. Homologous genes are also shown to be present in a number of taxonomically diverse plant genera tested, suggesting that this gene may have a conserved function in plants. The protein encoded by this gene is able to correct significantly the sensitivity to the cross-linking agent mitomycin C in ERCC1-deficient Chinese hamster ovary (CHO) cells. These findings suggest that the NER mechanism is conserved in yeast, animals and higher plants.

A comparison of a community mental health centre-based psychiatric service with one based in an outpatient department at the same hospital

Referrals and response to referrals of two psychiatric services with similar catchment areas of the same hospital, one with a Community Mental Health Care (CMHC) centre and the other based at an outpatient department, were compared over a five-month period. While the service with a CMHC had an increased number of referrals, which may reflect the aims of the CMHC of making mental health services more accessible and less stigmatised, most referrals were from general practitioners and therefore likely to be appropriate. In spite of its increased workload, the time from referral to assessment for the CMHC-based service was significantly shorter than for the outpatient-based service.

Identification of a Ca2+ binding protein as a new Bermuda grass pollen allergen Cyn d 7: IgE cross-reactivity with oilseed rape pollen allergen Bra r 1

cDNA clones encoding two isoforms of an allergen from pollen of Bermuda grass (Cynodon dactylon) have been isolated using IgE from allergic patients. Homologous transcripts are present in pollen of 15 other grasses tested. This allergen, tentatively designated as Cyn d 7, contains two calcium binding domains and shows significant sequence similarity with other Ca2+ binding pollen allergens, namely Bet v 4 from birch and Bra r 1 from oilseed rape. Approximately 10% of allergic sera tested showed IgE reactivity to this allergen. IgE cross-reactivity was observed between this allergen and Bra r 1 of oilseed rape. IgE reactivity of this allergen requires protein-bound Ca2+. Using IgE affinity-purified from the recombinant allergen to probe Western blots of pollen extracts Cyn d 7 has been identified as a 12 kDA protein.

Infant feeding and weaning practices in some semi-arid rural areas of Rajasthan

The paper contains information on infant feeding and weaning practices in the rural communities of a semi-arid district of Rajasthan. The findings have been drawn from a recent survey of 328 rural mothers. The rural women of this area are found to believe in old deep seated beliefs and customs, which in turn deprive their infants from advantages of colostrum (77% discarded colostrum) and nutritionally rich supplements, which otherwise should be supplemented to them at any cost in order to keep them healthy. The practices of prolonged breast feeding and delayed supplementation to infants are rampant in this area. Mean age at weaning (27.1 months) again not only affects the health status of mothers and their children but also leads to the undernutrition among both. The findings of the study necessitate to evolve an exhaustive educative programme dealing with various aspects of infant feeding and weaning practices, keeping in view their traditions, so that the useful practices can be encouraged and harmful ones be prohibited.

Knowledge and attitudes of pregnant women regarding AIDS in a semi arid area of Rajasthan

A total of 792 pregnant women from three hospitals of Jaipur were surveyed to assess and compare their knowledge and attitudes regarding various aspects of AIDS. Observations revealed that level of knowledge was significantly higher in pregnant women from upper income group than low income group (P < 0.05). The misconceptions regarding various aspects of AIDS viz. symptoms and signs, transmission and prevention and opinion towards the AIDS patients, indicate that there is strong need of AIDS education compaign in pregnant women too.

Effect of three hours of hypoxia on atrial natriuretic factor gene expression in the ovine fetal heart

OBJECTIVES

The current study investigated the effects of 3 hours of hypoxia on atrial natriuretic factor gene expression and peptide content in each of the four cardiac chambers of the near-term ovine fetus.

STUDY DESIGN

Twenty-three chronically catheterized ovine fetuses at 125 to 129 days' gestation (term 145 days) were used for this study. Fetal hypoxia was induced for 3 hours in 12 fetuses by infusion of nitrogen into the maternal trachea. The remaining fetuses were used as controls. Fetal arterial PO2 and plasma atrial natriuretic factor concentrations were measured during hypoxia. At the end of the hypoxic period atrial natriuretic factor peptide contents and messenger ribonucleic acid levels in each cardiac chamber were determined by radioimmunoassay and Northern blot analysis, respectively.

RESULTS

With infusion of nitrogen into the maternal trachea, fetal arterial PO2 was reduced within 30 minutes by an average of 8.0 +/- 0.3 (SEM) mm Hg (p < 0.0001) and remained reduced at this level throughout the entire hypoxic period. Plasma atrial natriuretic factor concentrations increased by 1152 +/- 212 pg/ml (p < 0.003) and the increase was sustained for the duration of hypoxia. Atrial natriuretic factor peptide and messenger ribonucleic acid levels were much higher in the atria than in the ventricles. Hypoxia did not result in alterations of atrial natriuretic factor peptide content or messenger ribonucleic acid abundance in each cardiac chamber.

CONCLUSIONS

In the near-term ovine fetus, 3 hours of hypoxia resulted in greatly elevated plasma atrial natriuretic factor concentrations; this response was sustained for the duration of hypoxia. However, the increase was not associated with a detectable change in atrial natriuretic factor peptide content or an induction of atrial natriuretic factor gene expression in the atria and ventricles.

Generative cells of Lilium longiflorum possess translatable mRNA and functional protein synthesis machinery

Metabolic labelling with [35S]-methionine demonstrated that generative cells of Lilium longiflorum possess their own set of mRNA and are capable of synthesising proteins independently from the vegetative cell. The isolated generative cells synthesised ten proteins, of which six were unique to these specialised cells. Isolation of generative cells from pollen grains after [35S]-methionine labelling resulted in an identical protein profile, therefore the synthesis of these proteins was not due to isolation shock. Addition of cycloheximide, abolished TCA-precipitable counts, whilst actinomycin D had no qualitative effect on the observed protein profile, indicating active translation of pre-existing mRNAs by the generative cells.

Cloning and expression in yeast Pichia pastoris of a biologically active form of Cyn d 1, the major allergen of Bermuda grass pollen

BACKGROUND

Pollen of grasses, such as Bermuda grass (Cynodon dactylon), represent a major cause of type I allergy.

OBJECTIVE

In this report we attempted to clone and express a biologically active form of recombinant Cyn d 1, the major allergen of Bermuda grass pollen, in the yeast Pichia pastoris.

METHODS

Clones encoding Cyn d 1 were isolated by screening a Bermuda grass pollen complementary DNA library with specific monoclonal antibodies and by polymerase chain reaction amplification. Recombinant Cyn d 1 was expressed in Escherichia coli and yeast. The expressed proteins were analyzed by Western blotting to assess binding to Cyn d 1-specific monoclonal antibodies and IgE from sera of patients allergic to Bermuda grass pollen.

RESULTS

Two isoforms of Cyn d 1 were cloned. Recombinant Cyn d 1 expressed in bacteria bound two monoclonal antibodies raised against Cyn d 1 but was not recognized by IgE from sera of patients allergic to Bermuda grass pollen. Cyn d 1 expressed in yeast bound both the monoclonal antibodies and human IgE.

CONCLUSION

An IgE-reactive Cyn d 1 was expressed in yeast but not in bacteria, suggesting that posttranslational modifications (e.g., glycosylation), which occur in eukaryotic cells such as yeast, are necessary for the production of a biologically active allergen.