Can we identify allergic rhinitis from administrative data: A validation study.

BACKGROUND: Important insights on, for example, prevalence, disease progression, and treatment of allergic rhinitis can be obtained from large-scale database studies if researchers are able to identify allergic individuals. We aimed to assess the validity of 13 different algorithms based on Danish nationwide prescription and/or hospital data to identify adults with allergic rhinitis. METHODS: Our primary gold standard of allergic rhinitis was a positive serum specific IgE (≥0.35) and self-reported nasal symptoms retrieved from two general health examination studies conducted in Danish adults (18-69 years) during 2006 to 2008 (n = 3416) and 2012 to 2015 (n = 7237). The secondary gold standard of allergic rhinitis was self-reported physician diagnosis. We calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value, and corresponding 95% confidence intervals (95% CI) for each register-based algorithm in the two time periods. RESULTS: Sensitivity (≤0.40) was low for all algorithms irrespective of definition of allergic rhinitis (gold standard) or time period. The highest PPVs were obtained for algorithms requiring both antihistamines and intranasal corticosteroids; yielding a PPV of 0.69 (0.62-0.75) and a corresponding sensitivity of 0.10 (0.09-0.12) for the primary gold standard of allergic rhinitis in 2012 to 2015. CONCLUSION: Algorithms based on both antihistamines and intranasal corticosteroids yielded the highest PPVs. However, the PPVs were still moderate and came at the expense of low sensitivity when applying the strict primary gold standard (sIgE and nasal symptom).

Reference equations for pulmonary diffusing capacity of carbon monoxide and nitric oxide in adult Caucasians.

The aim of this study was to determine reference equations for the combined measurement of diffusing capacity of the lung for carbon monoxide (CO) and nitric oxide (NO) (DLCONO). In addition, we wanted to appeal for consensus regarding methodology of the measurement including calculation of diffusing capacity of the alveolo-capillary membrane (Dm) and pulmonary capillary volume (Vc).DLCONO was measured in 282 healthy individuals aged 18-97 years using the single-breath technique and a breath-hold time of 5 s (true apnoea period). The following values were used: 1) specific conductance of nitric oxide (θNO)=4.5 mLNO·mLblood-1·min-1·mmHg-1; 2) ratio of diffusing capacity of the membrane for NO and CO (DmNO/DmCO)=1.97; and 3) 1/red cell CO conductance (1/θCO)=(1.30+0.0041·mean capillary oxygen pressure)·(14.6/Hb concentration in g·dL-1).Reference equations were established for the outcomes of DLCONO, including DLCO and DLNO and the calculated values Dm and Vc Independent variables were age, sex, height and age squared.By providing new reference equations and by appealing for consensus regarding the methodology, we hope to provide a basis for future studies and clinical use of this novel and interesting method.

Verbal learning and memory outcome in selective amygdalohippocampectomy versus temporal lobe resection in patients with hippocampal sclerosis.

PURPOSE: With the advent of new very selective techniques like thermal laser ablation to treat drug-resistant focal epilepsy, the controversy of resection size in relation to seizure outcome versus cognitive deficits has gained new relevance. The purpose of this study was to test the influence of the selective amygdalohippocampectomy (SAH) versus nonselective temporal lobe resection (TLR) on seizure outcome and cognition in patients with mesial temporal lobe epilepsy (MTLE) and histopathological verified hippocampal sclerosis (HS). METHODS: We identified 108 adults (>16years) with HS, operated between 1995 and 2009 in Denmark. Exclusion criteria are the following: Intelligence below normal range, right hemisphere dominance, other native languages than Danish, dual pathology, and missing follow-up data. Thus, 56 patients were analyzed. The patients were allocated to SAH (n=22) or TLR (n=34) based on intraoperative electrocorticography. Verbal learning and verbal memory were tested pre- and postsurgery. RESULTS: Seizure outcome did not differ between patients operated using the SAH versus the TLR at 1year (p=0.951) nor at 7years (p=0.177). Verbal learning was more affected in patients resected in the left hemisphere than in the right (p=0.002). In patients with left-sided TLR, a worsening in verbal memory performance was found (p=0.011). Altogether, 73% were seizure-free for 1year and 64% for 7years after surgery. CONCLUSION: In patients with drug-resistant focal MTLE, HS and no magnetic resonance imaging (MRI) signs of dual pathology, selective amygdalohippocampectomy results in sustained seizure freedom and better memory function compared with patients operated with nonselective temporal lobe resection.

Aberrant expression of miR-218 and miR-204 in human mesial temporal lobe epilepsy and hippocampal sclerosis-convergence on axonal guidance.

OBJECTIVE: Mesial temporal lobe epilepsy (MTLE) is one of the most common types of the intractable epilepsies and is most often associated with hippocampal sclerosis (HS), which is characterized by pronounced loss of hippocampal pyramidal neurons. microRNAs (miRNAs) have been shown to be dysregulated in epilepsy and neurodegenerative diseases, and we hypothesized that miRNAs could be involved in the pathogenesis of MTLE and HS. METHODS: miRNA expression was quantified in hippocampal specimens from human patients using miRNA microarray and quantitative real-time polymerase chain reaction RT-PCR, and by RNA-seq on fetal brain specimens from domestic pigs. In situ hybridization was used to show the spatial distribution of miRNAs in the human hippocampus. The potential effect of miRNAs on targets genes was investigated using the dual luciferase reporter gene assay. RESULTS: miRNA expression profiling showed that 25 miRNAs were up-regulated and 5 were down-regulated in hippocampus biopsies of MTLE/HS patients compared to controls. We showed that miR-204 and miR-218 were significantly down-regulated in MTLE and HS, and both were expressed in neurons in all subfields of normal hippocampus. Moreover, miR-204 and miR-218 showed strong changes in expression during fetal development of the hippocampus in pigs, and we identified four target genes, involved in axonal guidance and synaptic plasticity, ROBO1, GRM1, SLC1A2, and GNAI2, as bona fide targets of miR-218. GRM1 was also shown to be a direct target of miR-204. SIGNIFICANCE: miR-204 and miR-218 are developmentally regulated in the hippocampus and may contribute to the molecular mechanisms underlying the pathogenesis of MTLE and HS.

The longitudinal relationship of changes of adiposity to changes in pulmonary function and risk of asthma in a general adult population.

BACKGROUND: Adiposity has been linked to both higher risk of asthma and reduced lung function. The effects of adiposity on asthma may depend on both atopic status and gender, while the relationship is less clear with respect to lung function. This study aimed to explore longitudinal weight changes to changes in forced expiratory volume in first second (FEV1) and forced vital capacity (FVC), as well as to incident cases of asthma and wheezing, according to atopy and gender. METHODS: A general population sample aged 19-72 years was examined with the same methodology five years apart. Longitudinal changes in weight, body mass index, waist circumference, and fat percentage (bio-impedance) were analyzed with respect to changes of FEV1 and FVC (spirometry), and incidence of asthma and wheezing (questionnaire). Gender, atopy (serum specific IgE-positivity to inhalant allergens) and adipose tissue mass prior to adiposity changes were examined as potential effect modifiers. RESULTS: A total of 2,308 persons participated in both baseline and five-year follow-up examinations. Over the entire span of adiposity changes, adiposity gain was associated with decreasing levels of lung function, whereas adiposity loss was associated with increasing levels of lung function. All associations were dependent on gender (p-interactions < 0.0001). For one standard deviation weight gain or weight loss, FEV1 changed with (+/-)72 ml (66-78 ml) and FVC with (+/-)103 ml (94-112 ml) in males. In females FEV1 changed with (+/-) 27 ml (22-32 ml) and FVC with (+/-) 36 ml (28-44 ml). There were no changes in the FEV1/FVC-ratio. The effect of adiposity changes increased with the level of adipose tissue mass at the start of the study (baseline), thus, indicating an aggregate effect of the total adipose tissue mass. Atopy did not modify these associations. There were no statistically significant associations between changes in adiposity measures and risk of incident asthma or wheeze. CONCLUSIONS: Over a five-year period, increasing adiposity was associated with decreasing lung function, whereas decreasing adiposity was associated with increasing lung function. This effect was significantly greater in males than in females and increased with pre-existing adiposity, but was independent of atopy.

The association of vitamin K status with lung function and disease in a general population.

Introduction: Matrix Gla protein (MGP) is an inhibitor of lung tissue calcification. The plasma level of dephosphorylated-uncarboxylated MGP (dp-ucMGP) is a biomarker of vitamin K status. The present study assessed whether lower vitamin K status (reflected by higher dp-ucMGP) was associated with lung function and lung disease/symptoms. Methods: A general population sample of 4092 individuals, aged 24 to 77 years, underwent a health examination including questionnaires, spirometry and measurements of plasma dp-ucMGP. Associations of dp-ucMGP with lung function and self-reported disease/symptoms were estimated using regression models adjusted for age, sex and height. Associations were expressed as ß-estimates or odds ratios (ORs) per doubling in dp-ucMGP. Results: Lower vitamin K status (higher dp-ucMGP) was associated with lower forced expiratory volume in 1 s (FEV1) (98 mL; 95% CI: 54-141 mL) and lower forced vital capacity (FVC) (136 mL; 95% CI: 85-187 mL). Dp-ucMGP was not associated with the FEV1/FVC ratio (0.0 percentage points higher than the expected value; 95% CI: -1.0-1.0). Furthermore, lower vitamin K status was associated with COPD (OR 2.24, 95% CI: 1.53-3.27), wheezing (OR 1.81, 95% CI: 1.44-2.28) and asthma (OR 1.44, 95% CI: 1.12-1.83). Conclusion: Lower vitamin K status was associated with lower ventilatory capacity (lower FEV1 and FVC), and with higher risk of self-reported asthma, COPD and wheezing. Vitamin K status was not associated with airflow obstruction (FEV1/FVC ratio).

Epidemiology of non-hereditary angioedema.

The prevalence of non-hereditary angioedema was investigated in a general population sample (n = 7,931) and in a sample of Danish patients (n = 7,433) tested for deficiency of functional complement C(1) esterase inhibitor protein (functional C(1) INH). The general population sample (44% response rate) reported a lifetime prevalence of 7.4% for angioedema. In both groups symptoms were most frequent in the lips, head, neck, eyes and tongue. In the C(1) INH test normal group angioedema was still active at the time of the study in 53% of the patients, and 36% reported symptoms in the throat, 23% in the abdominal area, 17% had diarrhoea, 11% had vomiting and 6% fainted during attacks. Non-hereditary angioedema has high lifetime prevalence and becomes chronic in approximately 50% of affected patients. Symptoms in the larynx and throat, as well as non-specific symptoms, such as dizziness and abdominal pain, were more frequent than previously reported.

Validation of spirometer calibration syringes.

The volume calibration syringe is probably the single most important instrument in pulmonary function laboratories, yet no validation results have been published. In this study a sample of volume calibration syringes was validated. We weighed a 1-L and two 3-L calibration syringes before and after emptying them of water and determined the corresponding volume of gas by using a modified rolling seal spirometer. In this way we established an unbroken calibration chain between a certified weight of water and the corresponding volume of gas. The volume of a spirometer calibration syringe could be verified with an accuracy of ± 15 ml. The modified rolling seal spirometer had an accuracy of ± 11 ml at a volume of 1 L and ± 13 ml at a volume of 3 L. A sample of spirometer calibration syringes was validated and all syringes except for two small 1-liter syringes all had volumes within the label claimed volume ± 0.5%. Spirometer calibration syringes have a stable stroke volume even after many years of use and storage but have to be calibrated yearly to comply with international standard.

Prevalence, predictors, and clinical relevance of α-gal sensitization in patients with chronic urticaria.

BACKGROUND: Little is known about α-gal (galactose-α-1,3-galactose) sensitization in patients with chronic urticaria (CU). The aim of this study was to examine the prevalence, predictors and clinical relevance of α-gal sensitization in patients with CU. METHODS: Two consecutive cohorts of newly referred patients with CU from a primary care allergology practice and a tertiary hospital dermatology department, plus a control group with allergic disease, but not CU, from the allergology practice, were interviewed and screened for α-gal sensitization (serum specific-IgE ≥0.35 KU/L). RESULTS: Of 733 patients included, 21 (5.6%) and 11 (3.9%) of CU patients from private practice and hospital, respectively, were α-gal sensitized. In total, 8 patients (38.1% of sensitized patients, and 2.1% of all CU patients) from private practice, and 2 patients (18.2% of sensitized patients, and 0.7% of all CU patients) from hospital, had clinically relevant α-gal allergy. In private practice, male sex (47.6 vs. 24.7%), p = 0.020, obesity (33.3 vs. 23.6%), p = 0.302, and frequency of angioedema (61.9 vs. 51.4%), p = 0.350; and in hospital, male sex (72.7 vs. 27.9%), p = 0.003, and high total immunoglobulin E (median 168 vs. 70.5 KU/L), p = 0.022 were associated with α-gal sensitization. CONCLUSION: α-gal sensitization is observed in a small fraction of CU patients with only few patients experiencing clinically relevant sensitization. Certain patients, particularly from primary care, may constitute a relevant population for aimed testing.

Investigation of the interaction between modified ISCOMs and stratum corneum lipid model systems.

The modified ISCOMs, so-called Posintro nanoparticles, provide an opportunity for altering the surface charge of the particles, which influences their affinity for the negatively charged antigen sites, cell membranes and lipids in the skin. Hypothetically, this increases the passage of the ISCOMs (or their components) and their load through the stratum corneum. The subsequent increase in the uptake by the antigen-presenting cells results in enhanced transcutaneous immunization. To understand the nature of penetration of Posintro nanoparticles into the intercorneocyte space of the stratum corneum, the interaction between the nanoparticles and lipid model systems in form of liposomes and/or supported lipid bilayer was studied. As a lipid model we used Stratum Corneum Lipid (SCL), a mixture similar in composition to the lipids of the intercorneocyte space. By Förster Resonance Energy Transfer (FRET), Atomic Force Microscopy (AFM), Electrochemical Impedance Spectroscopy (EIS) and cryo-Transmission Electron Microscopy (cryo-TEM) it was shown that application of nanoparticles to the SCL bilayers results in lipid disturbance. Investigation of this interaction by means of Isothermal Titration Calorimetry (ITC) confirmed existence of an enthalpically unfavorable reaction. All these methods demonstrated that the strength of electrostatic repulsion between the negatively charged SCL and the nanoparticles affected their interaction, as decreasing the negative charge of the Posintro nanoparticles leads to enhanced disruption of lipid organization.

Indoor exposure to environmental cigarette smoke, but not other inhaled particulates associates with respiratory symptoms and diminished lung function in adults.

BACKGROUND AND OBJECTIVE: Exposure to particulate matter (PM) can induce airway inflammation and exacerbation of asthma. However, there is limited knowledge about the effects of exposure to indoor sources of PM. We investigated the associations between self-reported exposure to indoor sources of PM and lower airway symptoms and lung function. METHODS: A population-based cross-sectional study of 3471 persons aged 18-69 years was conducted. Information about exposure to indoor sources of PM and airway symptoms was obtained from a self-administered questionnaire. RESULTS: Exposure to wood stoves, candles and gas cookers was not significantly associated with an increased prevalence of lower respiratory symptoms or decreased lung function. In contrast, persons exposed to environmental tobacco smoke for >5 h/day had a significantly increased risk of 'wheeze' (OR 1.69, 95% CI: 1.24-2.30) and 'chronic cough' (OR 1.57, 95% CI: 1.12-2.20), as well as decreased lung function (FEV(1)% predicted), compared with those who were not exposed. Similar trends were observed in never smokers. CONCLUSIONS: In this cross-sectional study of an adult general population, self-reported exposure to environmental tobacco smoke, but not self-reported exposure to wood stoves, candles or gas cookers, appeared to be associated with an increased prevalence of lower airway symptoms and decreased lung function.

Cyclodextrin controlled release of poorly water-soluble drugs from hydrogels.

The effect of 2-hydroxypropyl-beta-cyclodextrin and gamma-cyclodextrin on the release of ibuprofen, ketoprofen and prednisolone was studied. Stability constants calculated for inclusion complexes show size dependence for complexes with both cyclodextrins. Hydrogels were prepared by ultraviolet irradiation and release of each model drug was studied. For drugs formulated using cyclodextrins an increase in the achievable concentration and in the release from hydrogels was obtained due to increased solubility, although the solubility of all gamma-cyclodextrin complexes was limited. The load also was increased by adjusting pH for the acidic drugs and this exceeds the increase obtained with gamma-cyclodextrin addition.

High glycogen levels in the hippocampus of patients with epilepsy.

During intense cerebral activation approximately half of the glucose plus lactate taken up by the human brain is not oxidized and could replenish glycogen deposits, but the human brain glycogen concentration is unknown. In patients with temporal lobe epilepsy, undergoing curative surgery, brain biopsies were obtained from pathologic hippocampus (n=19) and from apparently 'normal' cortical grey and white matter. We determined the in vivo brain glycogen level and the activity of glycogen phosphorylase and synthase. Regional differences in glycogen concentration were examined similarly in healthy pigs (n=5). In the patients, the glycogen concentration in 'normal' grey and white matter was 5 to 6 mmol/L, but much higher in the hippocampus, 13.1+/-4.3 mmol/L (mean+/-s.d.; P<0.001); the activities of glycogen phosphorylase and synthase displayed the same pattern. In normal hippocampus from pigs, glycogen was similarly higher than in grey and white matter. Consequently, in human grey and white matter and, particularly, in the hippocampus of patients with temporal lope epilepsy, glycogen constitutes a large, active energy reserve, which may be of importance for energy provision during sustained synaptic activity as epileptic seizures.

[Idiopathic oedema].

Idiopathic oedema is a non-inflammatory interstitial oedema seen in fertile women. A hallmark is a daily increase in weight > 1.4 kg from morning until evening due to fluid retention, which shows as facial puffiness in the morning and more often abdominal increase and swollen lower extremities during the day. Patients may be disabled due to accompanying symptoms like headache, dizziness, fatigue, anxiety, and depression. The diagnosis is based on clinical features and exclusion of other causes of oedema. Non-pharmacological interventions and pharmacological therapies are reviewed.

Pharmacodynamics of remifentanil. Induced intracranial spike activity in mesial temporal lobe epilepsy.

Patients with medically refractory epilepsy may benefit from resective epilepsy surgery. However even the best centers experience surgical failures. It is therefore important to find techniques that may aid in neurosurgical planning of epileptic focus resection. Recordings of electrical brain activity with EEG during seizures reveal abnormal cortical hypersynchronization. Between seizures the EEG often shows interictal depolarizing phenomena such as spikes reflecting an irritable focus of the brain. In the present study we investigated the effect of intravenous remifentanil on the spike activity in the temporal neocortex and hippocampus. We examined 65 patients with mesial temporal lobe epilepsy during surgery, prior to resection. We used a 20-lead grid on the cortex and a 4-lead strip in the lateral ventricle on the hippocampus. At least two 3-min periods of ECoG were recorded - before and after remifentanil injection. In a number of patients we examined the effect of repeated injections in order to estimate the dose-response curve. We describe a significant effect of remifentanil on the average spike activity with an increment from 16 spikes per minute at baseline to 36 spikes per minute after remifentanil injection (p<0.0001). The increase in spike activity was typically seen after 40-50s. When mu-receptors were antagonized with a preceding injection of naloxone, spike activity increased 25% in response to remifentanil as opposed to 80% when remifentanil was preceded by placebo. In only seven out of 59 patients did the injection of remifentanil change the topographic location of the spike focus. Typically administration of remifentanil led to a focus of increased spike count. Activity in other areas was suppressed making the focus stand out from the background. Our observation that remifentanil potentiates spike activity is in agreement with previous findings from smaller studies. Furthermore, we were able to describe the pharmacodynamics of the remifentanil effect on spike activity. Peri-operative provocation with remifentanil may play a future role in guiding neurosurgical intervention during epilepsy resection surgery.

Danish experience with paediatric epilepsy surgery.

INTRODUCTION: Epilepsy surgery is increasingly used to treat children with medically intractable epilepsy. This study investigates the aetiology and seizure outcome in Danish children operated between 1996 and 2010. METHODS: Retrospectively collected data on structural magnetic resonance imaging (MRI) diagnoses, surgical procedures and seizure outcomes classified according to the Engel Classification were used. Changes over time grouped as 1996-2000, 2001-2005 and 2006-2010 were analysed. RESULTS: A total of 95 children underwent epilepsy surgery. Sixty-three operations were performed in Denmark and 50 abroad. In all, 14 children needed reoperation. The median follow-up period was four years. At the latest follow-up, Engel class I (indicating no disabling seizures) was found in 67% of the patients. Cortical dysplasia, mesial temporal sclerosis and tumour were the most common MRI findings. The percentage of tumours operated decreased over time, and frontal lobe resections increased. In the 2006-2010 period, resections with normal MRI were performed, resulting in a less favourable Engel outcome. Persistent, unexpected complications were seen in three of 113 operations. CONCLUSIONS: The majority of children who undergo epilepsy surgery have a good, worthwhile seizure outcome. The seizure outcome for Danish children corresponds to that of other epilepsy surgery centres. The clinical criteria for selection of patients changed over time. FUNDING: none. TRIAL REGISTRATION: The Danish Data Protection Agency approved the project with record number: 2013-41-2459.

Release of chemical permeation enhancers from drug-in-adhesive transdermal patches.

There is only limited knowledge of how chemical permeation enhancers release from transdermal drug delivery systems of the drug-in-adhesive type. In this study, the release of eight commonly known enhancers from eight types of polymer adhesives was evaluated using Franz diffusion cells. It was shown that all the enhancers released completely from the adhesives and followed a square root of time kinetic (Higuchi law). Using a statistical analysis it was shown that the release rate was more dependent on the type of enhancer than on the type of polymers. The mean release rates were in the range from 2.2 to 11.1%/ radical t for the slowest and fastest releasing enhancers, which correspond to a 50% release within 500 and 20 min, respectively. Furthermore, the release rates were inversely proportional to the cube root of the molal volumes of the enhancers and to their logarithmic partition coefficients between the polymer adhesive and the receptor fluid. It was found that the observed release rates were probably due to a high diffusion coefficient of the enhancers rather than due to an inhomogeneous embedment of the enhancers in the adhesives. The type of adhesive showed minor influence on the release rate, especially among the acrylic polymers no difference was seen. However, compared to the acrylic adhesives, the polyisobutylene adhesive showed slower release rates, while the silicone adhesive showed slightly faster release rates.

Application of confocal laser scanning microscopy in characterization of chemical enhancers in drug-in-adhesive transdermal patches.

The purpose of this study was to evaluate the application of confocal laser scanning microscopy (CLSM) in the examination of the embedment and the release characteristics of chemical permeation enhancers from transdermal drug delivery systems (TDDSs) of the "drug-in-adhesive" type. The enhancer lauric acid and a lauric acid fluorescing probe of the Bodipy type were incorporated into TDDSs consisting of an acrylic, a polyisobutylene, or a silicone polymer adhesive. Three-dimensional confocal images of the distribution were obtained before and during release into an aqueous medium. The images showed that the lauric acid fluorescing probe was homogeneously embedded in all the adhesives except for 1 polyisobutylene. The release profiles and release rate constants of the lauric acid fluorescing probe were consistent with data from a release study of lauric acid performed using conventional measurements of the released amounts. This indicated that lauric acid was distributed in a homogeneous manner. Furthermore, it was possible to illustrate the mechanics of the diffusion process inside the TDDS and compare these patterns with theoretically drawn profiles, based on Fick's law of diffusion. CLSM was demonstrated to be an excellent tool to study how enhancers are incorporated and diffuse into a TDDS.

[Length of stay in medical departments. Similarities and differences in Denmark]. / Liggetid på medicinske afdelinger. Ligheder og forskelle i Danmark.

INTRODUCTION: The relation between the length of stay after admission to a medical ward, the available resources, and the quality of the results is not well established. There is no documentation that allocation of resources results in improved quality. In Denmark we have recently focused on the quality of cancer treatment and have allocated resources without any evidence that it will improve survival, whereas less attention has been paid to less prestigious diseases. Length of stay can be an indicator of quality, as we operate with an efficient work process as a goal. But it is not a goal by itself, as only when coupled with cure or improvement in the disease can it be worth aiming at. We therefore compared the length of stay in Danish Departments of Internal Medicine to look for differences or similarities. MATERIAL AN METHODS: The homepage of the Danish National Board of Health, www.tal.dk (now terminated) was visited and data drawn for analyses. RESULTS: Six days seems to be the average length of stay in most departments, with some extreme deviations. A tendency towards a short stay in the department of Cardiology and a long term stay in the Geriatric Department was found as expected, but again extreme deviations were seen. DISCUSSION: No typical pattern was seen in the length of stay. A short stay is not attractive in itself, only when combined with a high quality of care and a healthy economy. Conversely, too short a stay can be risky if it is because of overcrowding and this must be prevented.