Effect of khat chewing on periodontal pathogens in subgingival biofilm from chronic periodontitis patients

Epidemiology of Khat (Catha edulis) Chewing in Ethiopia: A Systematic Review and meta-analysis

In several countries, including Ethiopia, the shrub Catha edulis (khat) leaves are chewed for their stimulant properties. The present review summarizes evidence on the prevalence of khat use in Ethiopia and forwards recommendations for future action. PubMed, Embase, and Scopus were searched for studies examining the prevalence of Khat chewing among adolescent and/or adult populations in Ethiopia. A random-effects model was employed to estimate the pooled prevalence of khat chewing. Of the 568 articles identified, 26 were included in the review. The pooled prevalence of current and lifetime khat use was 19.55% (95% CI 14.62-25.64) and 26.14% (CI 17.66-36.87), respectively. The current prevalence of khat use was higher in men, 23.72% (CI 13.42-38.41), than in women 8.45% (CI 4.94-14.08). Lifetime prevalence of khat use was higher in men, 29.8% (CI: 22.80-37.99) than in women 13.02% (CI 8.96-18.56). The results of the meta-analysis demonstrated a higher odds of current (OR = 4.00, CI 2.80-5.73) and lifetime (OR = 2.84, CI 2.50-3.23) khat use in men than in women. Our review found a high prevalence of current (19.55%) and lifetime (26.14%) khat chewing in Ethiopia and demonstrated higher odds of current and lifetime khat use in men than in women. Awareness creation and integrated management of khat use problems at the primary health-care level is highly recommended.

Reducing Khat use among Somalis living in Kenya: a controlled pilot study on the modified ASSIST-linked brief intervention delivered in the community

BACKGROUND

During recent decades, the consumption of the stimulant khat (catha edulis) has profoundly changed in countries around the Horn of Africa, and excessive use patterns have emerged-especially evident among displaced Somalis. This is related to the development of severe somatic and psychiatric disorders. There are currently no preventive or interventional studies targeting khat use. This study's aim was to test screening and brief intervention (SBI) to reduce khat use among urban Somali refugees living in Kenya with limited access to public healthcare.

METHODS

In this controlled study, 330 male Somali khat users from the community were either assigned to SBI (161) or an assessment-only control condition (AC; 169); due to field conditions a rigorous experimental design could not be implemented. The World Health Organization's (WHO) Alcohol, Smoking and Substance Involvement Screening Test (ASSIST)-linked brief intervention was adapted to khat and Somali culture. Trained local counselors administered the intervention. The amount and frequency of khat use was assessed using the time-line-follow-back method. We compared the month before the intervention (t1) to the two months after it (t2, t3). Baseline differences in khat use frequency were corrected by partial matching and mixed effect models used to evaluate intervention effects.

RESULTS

SBI was well accepted and feasible for khat users. Over the complete observation period and from t1 to t2, khat use amount and frequency decreased (p < .001) and the intervention group showed a greater reduction (group x time effects with p ≤ .030). From t2 to t3, no further reduction and no group differences emerged.

CONCLUSION

The results provide preliminary evidence that khat use amount and frequency can be reduced in community settings by SBI, requiring little resources. Thorough assessment alone might have intervention-like effects. The non-treatment-seeking community sample and the non-professional counselors are distinct from SBI studies with other substances in other countries, but support the feasibility of this approach in khat use countries and especially in Somali populations with limited access to healthcare. Future studies that employ rigorous experimental design are needed.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02253589. Date of first registration 01/10/2014, retrospectively registered https://clinicaltrials.gov/ct2/show/NCT02253589 . First participant 16/09/2014.

Bioremediation of hexavalent-chromium contaminated groundwater: Microcosm, column, and microbial diversity studies

Sulfate reducing bacteria (SRB) have the capability of bioreducing hexavalent chromium [Cr(VI)] to trivalent chromium [Cr(III)] under sulfate-reducing conditions for toxicity reduction. However, a high amount of sulfate addition would cause elevated sulfide production, which could inhibit the growth of SRB and result in reduced Cr(VI) bioreduction efficiency. A slow release reagent, viscous carbon and sulfate-releasing colloidal substrates (VCSRCS), was prepared for a long-lasting carbon and sulfate supplement. In the column study, VCSRCS was injected into the column system to form a VCSRCS biobarrier for Cr(VI) containment and bioreduction. A complete Cr(VI) removal was observed via the adsorption and bioreduction mechanisms in the column with VCSRCS addition. Results from X-ray diffractometer analyses indicate that Cr(OH)_3(s) and Cr₂O_3(s) were detected in precipitates, indicating the occurrence of Cr(VI) reduction followed by Cr(III) precipitation. Results from the Fourier-transform infrared spectroscopy analyses show that cell deposits carried functional groups, which could adsorb Cr. Addition of VCSRCS caused increased populations of total bacteria and dsrA, which also enhanced Cr(VI) reduction. Microbial diversity results indicate that VCSRCS addition resulted in the growth of Cr(VI)-reducing bacteria including Exiguobacterium, Citrobacter, Aerococcus, and SRB. Results of this study will be helpful in developing an effective and green VCSRCS biobarrier for the bioremediation of Cr(VI)-polluted groundwater.

Environmental occurrence and ecological risks of psychoactive substances

Psychoactive substances are ubiquitous in the environment at low concentrations, and tobacco, cannabis, etc. are all widely-existing examples. Given their potent biological activity, psychoactive substances are suspected to be harmful to the environment, and reports of their ecological risks are gradually increasing. Since the 1990s, the investigations into psychoactive substances have made remarkable progress, yet some research fields still need to be modernised. For example, the unification of standardised analytical methods as well as the supplementation of occurrence literature. In addition, a relatively lagging risk evaluation system caused by a lack of toxicity data is particularly in need of improvement. The purpose of this article is to develop a review of current research on psychoactive substances, including analytical methods, distribution in environmental compartments, and ecological risk assessment, as well as to point out deficiencies and development prospects and to offer motivation for enhancing the research level in this field.

Khat (Catha Edulis Forsk) induced apoptosis and cytotoxicity in cultured cells: A scoping review

Background

Khat (Catha edulis Forsk) leaves are chewed by people in certain regions of East Africa and the Middle East for their stimulating amphetamine-like effects. The purpose of this scoping review is to systematically map the current in vitro publications that investigated the toxicological potential effects of khat on cultured human or animal cells in terms of cellular viability and activity.

Methods

A comprehensive electronic database search was undertaken up to December 2020 without starting date or language restrictions in accordance with the PRISMA extension for scoping review guideline and methodological quality evaluation based on the guidelines for reporting pre-clinical in vitro studies on dental materials. All in vitro studies that investigated the effect of khat plant extract (Catha Edulis) on the cultured human or animal cells were included.

Results

The initial search yielded 599 articles and 16 articles were finally selected to be included. The treatment of cells with khat produced different degrees of cellular changes, including decreased cellular survival, induction of apoptosis, increased ROS production, alteration of cell phenotype, and of arrest cell cycle. In this contest, khat-exposed cells expressed higher levels of pro-apoptotic protein Bax and lower levels of anti-apoptotic Bcl-2, up-regulated p38, p53, p16, and p21 proteins, as well as premature expression of differentiation markers.

Conclusion

Based on the current scoping review, khat induced apoptosis and cytotoxicity in cultured human cells, including oral cells.

Autopsy, thanatopraxy, cemeteries and crematoria as hotspots of toxic organic contaminants in the funeral industry continuum

The occurrence and health risks of toxic organic contaminants (TOCs) in the funeral industry are relatively under-studied compared to other industries. An increasing body of literature reports TOCs including emerging contaminants in the funeral industry, but comprehensive reviews of the evidence are still lacking. Hence, evidence was analysed to address the proposition that, the funeral industry constitutes several hotspot reservoirs of a wide spectrum of TOCs posing ecological and human health risks. TOCs detected include embalming products, persistent organic pollutants, synthetic pesticides, pharmaceuticals, personal care products and illicit drugs. Human cadavers, solid wastes, wastewaters and air-borne particulates from autopsy, thanatopraxy care facilities (mortuaries, funeral homes), cemeteries and crematoria are hotspots of TOCs. Ingestion of contaminated water, and aquatic and marine foods constitutes non-occupational human exposure, while occupational exposure occurs via inhalation and dermal intake. Risk factors promoting exposure to TOCs include unhygienic burial practices, poor solid waste and wastewater disposal, and weak and poorly enforced regulations. The generic health risks of TOCs are quite diverse, and include; (1) genotoxicity, endocrine disruption, teratogenicity and neurodevelopmental disorders, (2) development of antimicrobial resistance, (3) info-disruption via biomimicry, and (4) disruption of ecosystem functions and trophic interactions. Barring formaldehyde and inferential evidence, the epidemiological studies linking TOCs in the funeral industry to specific health outcomes are scarce. The reasons for the lack of evidence, and limitations of current health risk assessment protocols are discussed. A comprehensive framework for hazard identification, risk assessment and mitigation (HIRAM) in the funeral industry is proposed. The HIRAM includes regulatory, surveillance and control systems such as prevention and removal of TOCs. Future directions on the ecotoxicology of mixtures, behaviour, and health risks of TOCs are highlighted. The opportunities presented by emerging tools, including isotopic labelling, genomics, big data analytics (e.g., machine learning), and in silico techniques in toxicokinetic modelling are highlighted.

The Relationship Between Khat Use Disorder and Post-Traumatic Stress Disorder Among Prisoners with Life Time Trauma Exposure in Ethiopia: A Cross-Sectional Study

BACKGROUND

Problematic khat use is an emerging health problem worldwide. Trauma experience, crime, and substance misuse is closely related. However, there is lack of evidence whether post-traumatic stress disorder (PTSD) and life time trauma exposure has a relationship with problematic khat use among prisoners in our country Ethiopia, or elsewhere. Therefore, this study assessed the relationship between PTSD and life time trauma exposure with khat use disorder among newly admitted prisoners in Bench Shako and West Omo zone correctional institution, Mizan Aman, Ethiopia.

METHODS

A cross-sectional study was conducted among 411 (N=422) prisoners from April 20 to July 19, 2019, by using a consecutive sampling technique. Trauma exposure and post-traumatic stress disorder were assessed with a life event check list and Post-traumatic stress disorder - civilian version (PCL-C), respectively. The WHO ASSIST tool was used to assess khat, alcohol, and tobacco use disorder. Antisocial personality disorder, criminal, and clinical history were also assessed. The data were entered into Epi-data version 3.1 and then exported to Statistical Package for Social Science version 21. A logistic regression model was used and variables with a p-value less than 0.05 in the final fitting model were stated as independent predictors of PTSD.

RESULTS

Nearly one out of four prisoners exposed to life time trauma exposure developed PTSD, and the prevalence of khat use disorder among prisoners with life time trauma exposure and PTSD was 45% and 85%, respectively. Prisoners with khat use disorder had more than 5 times higher odds of association with PTSD than their counterparts (AOR=5.3, 95% CI=2.4-11.8). In addition, antisocial personality disorder (AOR=2.8, 95% CI=1.6-5.5), criminal recidivism (AOR=2.5, 95% CI=1.5-4.3), and being a driver (AOR=2, 95% CI=1.2-3.3) were positively associated with PTSD.

CONCLUSION

Khat use disorder was higher among prisoners with life time trauma exposure and PTSD, and khat use disorder was positively associated with PTSD.

Prevalence of target anaerobes associated with chronic periodontitis

Introduction

Periodontal diseases are a group of chronic infections that destroy tissues surrounding and supporting the teeth. Data on the anaerobes associated with periodontal infections in Kuwait is lacking.

Aim

To investigate the target anaerobes associated with chronic periodontitis (CP) in patients admitted to Dental Clinics in Kuwait University Health Sciences Center, Kuwait.

Methodology

Patients with CP (severe and moderate) were recruited into this study during a period of 15 months. Samples were collected directly from inside the gingival pockets and subjected to semi-quantitative PCR assays.

Results

A total of 30 patients, stratified into moderate and severe CP and 31 healthy individuals, used as controls, were studied. Nine (30 %) of the 30 patients were in the 50–59-year age group. The detection rate of Aggregatibacter actinomycetemcomitans between the patients (9 : 30 %) versus the controls (5 : 16.1 %) was non-significant (P >0.05). Fusobacterium spp., were detected in all patients versus 29 (93.1 %) controls, (P >0.05). However, four target anaerobes were significantly associated with CP patients; Porphyromonas gingivalis was detected in ten (33.3 %) patients versus two (6.4 %) controls (P <0.0001); Tannerella forsythia 25 (83.3 %) versus 16 (51.6 %) controls (P <0.0001); Parvimonas micra 27 (90 %) versus 16 (51.6 %) controls (P <0.0001) and Treponema denticola, 18 (60 %) versus nine (29 %) controls (P <0.0001), respectively. Prevotella spp. were detected in 27 (90 %) patients and 30 (96.7 %) controls (P>0.5). There was no significant difference in the burden of Prevotella spp. between patients and controls determined by semi-quantitative PCR assays.

Conclusion

Some (4/7) of the target anaerobes were significantly associated with CP in our study. P. gingivalis was the most strongly associated anaerobe with CP, although not the keystone bacteria, while Prevotella spp. was similar to the healthy controls.

Oral Biofilm on Dental Materials Among Khat Chewers

BACKGROUND

Nowadays khat chewing habit is increasing among population in southern part of Saudi Arabia, Jazan and till date there is no literature investigating the effect of khat on oral biofilm on dental materials.

OBJECTIVE

To evaluate and compare the bacterial biofilm on different types of dental restorative materials used in replacing missing tooth structures among khat chewers and non-khat chewers.

MATERIALS AND METHODS

Hundred and twenty biofilm samples were collected from different dental restorations, such as All-ceramic (AL), Metal Ceramic (MC), Metal crowns or bridges (M), Composite (C), Glass Ionomer (GI) and Amalgam (A) restorations in non-khat and khat chewers (K). DNA extraction was done and subjected to PCR. Bacterial species, such as Streptococcus, Neisseria, Bacillus, Granulicatella and Veillonella were identified and counted. PCR products were also sequenced to detect similarity. Association between bacterial type and dental materials among non-khat and khat chewers were tested with Chi-Square test (Fishers Exact test).

RESULTS

The frequency and percentage of Streptococcus species were marginally higher among khat chewers (42; 70%) compared with non-khat chewers (38; 63.3%) group. But the Veillonella species were higher among non-khat chewers (9: 15%), compared to the khat chewers group (7; 11.7%). No statistically significant difference was detected among species in both groups. In non-khat and khat chewer group, the maximum hits were related to Streptococcus spp. in glass ionomer, amalgam, and composite (restorative materials), followed by metal ceramic and metal (prosthetic materials). Veillonella spp. showed maximum hits in the metal group among non-khat chewers and in all-ceramic among khat chewers. Statically significant differences were recorded among composite and amalgam samples with p values 0.047 and 0.036 in khat chewer group.

CONCLUSION

Khat chewers showed statistically significant differences in oral biofilm in the composite and amalgam restorative materials, but there were no significant differences found among any materials and species between the groups.

Supragingival mycobiome and inter-kingdom interactions in dental caries

Background: Recent studies have reveled the presence of a complex fungal community (mycobiome) in the oral cavity. However, the role of oral mycobiome in dental caries and its interaction with caries-associated bacteria is not yet clear.

Methods: Whole-mouth supragingival plaque samples from 30 children (6–10 years old) with no caries, early caries, or advanced caries were sequenced for internal transcribed spacer 2 (ITS-2). The mycobiome profiles were correlated with previously published bacteriome counterparts. Interaction among selected fungal and bacterial species was assessed by co-culture or spent media experiments.

Results: Fungal load was extremely low. Candida, Malassezia, Cryptococcus, and Trichoderma spp. were the most prevalent/abundant taxa. Advanced caries was associated with significantly higher fungal load and prevalence/abundance of Candida albicans. Cryptococcus neoformans and Candida sake were significantly over-abundant in early caries, while Malassezia globosa was significantly enriched in caries-free subjects. C. albicans correlated with Streptococcus mutans and Scardovia wiggsiae among other caries-associated bacteria, while M. globosa inversely correlated with caries-associated bacteria. In-vitro, M. globosa demonstrated inhibitory properties against S. mutans.

Conclusions: the results substantiate the potential role of the oral mycobiome, primarily Candida species, in dental caries. Inter-kingdom correlations and inhibition of S. mutans by M. globosa are worth further investigation.

Khat Chewing Induces a Floral Shift in Dental Material-Associated Microbiota: A Preliminary Study

Background

The habit of khat (Catha Edulis Forskal) chewing is widely practiced in the southern regions of Saudi Arabia, Yemen, and East Africa. This social habit has tremendous effects on oral and general health of khat chewers. Khat may affect bacterial species in plaque biofilms on oral rehabilitation materials. This preliminary case-controlled study aimed to assess and compare the effect of khat chewing on bacterial biodiversity between non-khat chewers (NKC) and khat chewers (KC) in oral biofilms on oral rehabilitation materials using polymerase chain reaction (PCR).

Material/Methods

Fifty participants were organized into 2 equal groups of NKC and KC, each containing 5 subgroups related to filling material type. Some participants had amalgam (A) or composite (C) restorations, while others had feldspathic porcelain (FP), nickel chromium (NC), and zirconia ceramic (ZC) crowns or bridges. Oral biofilm samples were collected from all participants, DNA was extracted, and samples were subjected to PCR. Bacterial species were then identified and counted. PCR products were sequenced to detect similarity. Partial 16S rRNA gene sequences of the current study samples were compared with 16S rRNA gene sequences from GenBank using BLAST on the National Center for Biotechnology Information website.

Results

The Streptococcus sp. was the most common bacterial species among our participants (40; 80%), followed by Lactobacillus and Veillonella spp., accounting for 12% (6) and 8% (4), respectively. Streptococcus sp. was observed equally among NKC and KC, but Lactobacillus and Veillonella spp. were higher in KC and NKC, respectively. Lactobacillus was associated mainly with prosthetic materials, and Streptococcus was found among all examined dental restorative materials.

Conclusions

This research concluded that khat chewing significantly affects bacterial biodiversity in oral biofilms in the presence of different restorative and prosthetic dental materials.

Clinical, in vitro and phytochemical, studies of Scrophularia striata mouthwash on chronic periodontitis disease

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic periodontitis is an inflammatory process of the oral cavity that is caused by different reasons. Streptococcus mutans bacteria is the main cause of the disease. Scrophularia striata in Iranian traditional medicine is used to heal inflammation of gum and mouth. Also, In vitro anti-bacterial effect of S. striata in S. mutans have been demonstrated.

AIM OF THE STUDY

Clinical, in vitro and chemical constituent studies of S. striata on chronic periodontitis disease.

MATERIALS AND METHODS

This study is a randomized clinical trial that was performed in Dental College, Hamadan University of Medical Sciences. Fifty patients with chronic periodontitis (20-50 years old) were selected and the study was approved and registered in Iranian Registry of Clinical Trials as number IRCT2015081323468N1 prior to the experiment. The 50 patients were divided into two groups. One group used herbal mouthwash that was made from hydro alcoholic extract of S. striata and another group used Irsha mouthwash (Iranian form of Listerine mouthwash). Patients were followed up after two weeks and four weeks of using mouthwash for assessment of plaque index (PI), pocket depth (PD), bleeding on probing (BOP) and counting Streptococcus mutans. The mouthwash was standardized according to gallic acid, quercetin and apigenin reference using the RP-HPLC method. The total phenolic and flavonoids contents were also determined spectrophotometerically.

RESULTS

S. striata in the short term, improve plaque index, pocket depth and bleeding on probing but the number of Streptococcus mutans changed significantly in the long term and is more potent in comparison to Irsha mouthwash. The mouthwash was standardized according to gallic acid, quercetin and apigenin standard (3, 24, 11 μg, respectively). The total phenolic and flavonoid content of mouthwash were 120.7 μg GAE/100 cc and 78.6 μg QE/100 cc respectively.

CONCLUSIONS

S. striata mouthwash is effective in the treatment of chronic periodontitis disease and is more potent comparing the Iranian Irsha mouthwash.

Epidemiology of khat (Catha edulis) consumption among university students: a meta-analysis

BACKGROUND

Khat is amphetamine-like substance commonly consumed by students when they wish to study for long hours especially during examination periods. Khat consumption is associated with increased rates of cardiovascular problems, stroke, myocardial infarction, cardiomyopathy, periodontal disease, gastritis, poor oral hygiene, psychosis, decreased quality of life, and poor academic performance.

METHODS

PubMed, EMBASE, and SCOPUS were systematically searched without restriction by publication status. Publications were screened according to predefined inclusion criteria. Twenty-five articles were included. Random effect model was used to calculate weighted prevalence, odds ratio (OR) and corresponding 95% confidence interval (CI). We assessed the risk of publication bias by using funnel plot and Eggers's regression tests.

RESULTS

The pooled prevalence of current khat use among university students was 14.16% (95% CI; 11.87-16.81). The pooled prevalence of current khat use was highest in Saudi Arabia 18.85% and it was 13.59% in Ethiopia and 13.04% in Yemen. In addition, the current pooled prevalence of khat use was higher in men at 19.26% than in women 6.41%. Regarding lifetime khat use, in this study, the pooled prevalence of lifetime khat use was 27.31%. The lifetime prevalence was higher in men at 31.47% than in women 11.79%. Moreover, the lifetime prevalence of khat use was 43.27% in Yemen, 37.32% in Saudi Arabia, and 24.82% in Ethiopia. We found significantly increased odds of current (OR 3.59; 95%CI 2.01-6.41) as well as lifetime (OR 3.48; 95%CI 2.09-5.78) khat chewing in men as compared to women.

CONCLUSION

The pooled prevalence of current and lifetime khat consumption was 14.16 and 27.31%, respectively. Both the current and lifetime prevalence of khat use was higher in men than in women. In addition, both the current and lifetime prevalence estimates of khat consumption were low in Ethiopia than in Saudi Arabia. Moreover, the odds of both current and lifetime khat consumption were higher in male students than in female students. Programmes that specifically aim at increasing awareness and that most motivate reduced khat consumption among university students were recommended.

The combined and individual impact of diabetes and smoking on key subgingival periodontal pathogens in patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

Comprehension of the similarities and differences in the composition of the subgingival microbiota of patients with diabetes mellitus (DM), smokers or smokers with DM is an important step in developing therapies specific for these groups at risk for periodontitis. Therefore, the aim of this study was to compare the combined and individual effects of DM and smoking on the levels and prevalence of key subgingival periodontal pathogens in patients with chronic periodontitis.

MATERIAL AND METHODS

One hundred patients with generalized chronic periodontitis were allocated into one of the following groups: DM (n = 25, non-smokers with type 2 DM); S (n = 25, non-diabetic smokers); SDM (n = 25, smokers with type 2 DM); and control (n = 25, non-diabetic non-smokers). Two subgingival biofilm samples from healthy sites (probing depth and clinical attachment level ≤3 mm and no bleeding) and 2 from diseased sites (probing depth and clinical attachment level ≥5 mm and bleeding on probing) were analyzed by quantitative polymerase chain reaction for Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Parvimonas micra, Fusobacterium nucleatum ssp. and Prevotella intermedia.

RESULTS

There were no differences among groups in the mean counts of the bacterial species studied, considering all sampled sites (healthy plus diseased sites). There were also no differences among groups regarding the prevalence of any bacteria species in healthy and diseased sites (P > .05). The mean P. micra count was significantly higher in the healthy sites of both smoking groups, than in those of the control group (P < .05).

CONCLUSION

The subgingival levels and prevalence of the bacterial species studied are not significantly different in subjects with chronic periodontitis presenting DM, smokers or smokers with DM. In addition, DM and smoking, jointly and individually, do not considerably affect the subgingival levels of target periodontal pathogens in patients with chronic periodontitis.

Comorbid psychopathology and everyday functioning in a brief intervention study to reduce khat use among Somalis living in Kenya: description of baseline multimorbidity, its effects of intervention and its moderation effects on substance use

BACKGROUND AND AIMS

Migration and khat use were found to correlate with high rates of psychopathology. In this paper we aimed for assessing baseline multimorbidity and its interactions with a Brief Intervention.

METHODS

In the RCT, 330 male Somali khat users were assigned to treatment conditions (khat use is a predominantly male habit). The ASSIST-linked BI for khat users was administered. Using the TLFB Calendar, the PHQ-9, a Somali short version of the PDS and parts from the CIDI, khat use and comorbidity was assessed. With a regression analysis we tested for the influence of comorbidity and with mixed effect models group differences over time in sleep duration, khat use-time and everyday functioning.

RESULTS

We found high rates of baseline multimorbidity: 51% (N = 168) for depression, 22% (N = 74) for PTSD and 23% (N = 73) for khat-psychotic symptoms. Depression and khat-psychotic symptoms, but not PTSD symptoms decreased without group differences. Khat use-time decreased and functional time increased with significant time × group interactions (p ≤ 0.046). Depression and PTSD did not influence therapy success but in participants without comorbid psychopathology, more khat use reduction after the intervention was found (p = 0.024).

CONCLUSION

Somali khat users in Kenya are highly burdened by multimorbidity of depression, PTSD and khat-psychotic symptoms. The main effects for time and differences in healthy vs. mentally ill khat users indicate potential of unspecific support and the specific need for mental health care in combination with substance abuse treatment. The increase of everyday functioning promises more options for alternative activities, preventing excessive use and addiction.

Is Khat (Catha edulis) chewing a risk factor for periodontal diseases? A systematic review

Background

Khat (Catha edulis) chewing is a highly prevalent habit in the Arabian Peninsula and East Africa, and has recently spread to Western countries. The association between khat chewing and oral mucosal lesions is well documented in the literature. However, there is no concrete evidence on the association between khat chewing and periodontal disease. The purpose of this systematic review was to analyze the influence of khat chewing on periodontal health.

Material and Methods

A literature search of PubMed, Scopus and Web of Sciences databases was carried out to identify relevant articles published from 1990 to May 2017. The inclusion criteria were all clinical studies that assessed the relationship between khat chewing and periodontal disease.

Results

The search yielded 122 articles, of which 10 were included in this systematic review. Most of the studies exhibited a positive correlation between khat chewing and periodontal disease.

Conclusions

Altogether, the analysis of the current evidence reveals that khat chewing is destructive to the periodontium and enhances the risk of periodontal disease progression. However, due to variability of studies, more longitudinal case-controlled studies are highly warranted to establish a causal relation between khat chewing and periodontal disease.

Key words:Khat chewing, periodontal health, periodontal disease, risk factor.

Khat (Catha edulis) and its oral health effects: An updated review

Khat or qat (Catha edulis) is a plant that grows in East Africa and southern Arabia. The leaves and twigs of this small tree are chewed by several millions of people worldwide for their stimulating amphetamine-like effects. The reported prevalence of khat chewing in Europe and the USA is on the rise, especially with global migration. Long-term khat chewing has several detrimental general and oral health effects. The aim of the present study was to review the current literature regarding khat use and its association with oral and dental diseases, with particular emphasis on its link with oral keratotic white lesions and oral cancer. We searched the literature to identify all relevant articles. Studies showed that khat is associated with several oral and dental conditions, including keratotic white lesions, mucosal pigmentation, periodontal disease, tooth loss, plasma cell stomatitis, and xerostomia. There are limited data on the incidence of dental caries among khat chewers. The evidence that khat chewing is a risk factor for oral cancer is still weak, and is mainly based on anecdotal case reports and uncontrolled studies.

Tooth Wear Patterns among Khat and Shammah Users in Jazan City, Kingdom of Saudi Arabia: A Cross-sectional Survey

AIM

The effect of Khat and Shammah habits, with the para-functional jaw activities that accompany them, on the structure and integrity of the natural dentition has not yet been investigated. The literature lacks studies that identify the patterns of tooth wear among Khat and Shammah users. Therefore, this study is the first attempt to address this concern in Jazan City population, Kingdom of Saudi Arabia.

MATERIALS AND METHODS

A cross-sectional survey study was conducted among 300 recruits among dental clinics in Jazan City, Kingdom of Saudi Arabia from October 1, 2015, to April 30, 2016. Questionnaires were used for data collection on oral habits (Khat and Shammah use), age, gender, intake of acidic food or beverages, food habits (intake of fruits, grains, and vegetables), systemic diseases, oral hygiene habits (brushing frequency, technique, and type of toothbrush), parafunctional habits, stress, and acid reflux. Clinical examination was performed to assess the grade of tooth wear. Bivariate analysis was performed to determine the empirical relationship between the independent variables and outcomes. In addition, binary logistic regressions were used to measure the relationship between the independent variables and each of the dependent variables (presence of occlusal wear, tooth wear grade 0 through 4).

RESULTS

Khat and Shammah use was statistically significantly associated with tooth wear (p < 0.05). A significant association of tooth wear was observed with age, gender, intake of acidic food and beverages, oral hygiene habits, and stress.

CONCLUSION

Consumption of Khat and Shammah may be attributed as one of the major reasons associated with tooth wear among the Saudi population.

CLINICAL SIGNIFICANCE

The habitual use of Khat and Shammah causes tooth wear of varying severity, which may negatively affect esthetics, phonetics, and function and necessitate a complex restorative treatment.

Oral hygiene and periodontal health status among khat chewers. A case-control study

Background

Habitual khat chewing is a widespread male habit in Southern Arabia and East Africa. The aim of this study was to assess the effect of Khat chewing on oral hygiene and periodontal health status among Yemeni male khat chewers.

Material and Methods

This case- control study included 310 khat chewers, aged 20-65 years, and 72 age- and gender- matched non-chewers as controls. Periodontal examination included recording of dental plaque index (PI), gingival index (GI), probing pocket depth (PPD), attachment level (AL) and gingival recession (GR). Demographic data, oral hygiene practices, and duration, frequency and site of khat chewing were obtained using questionnaires. SPSS was used for data analysis. ANOVA and t- tests were used to compare groups.

Results

Khat chewers had significantly higher mean PI, AL, GR scores than non-chewers (P < 0.05). However, no significant differences in the GI and PPD mean scores were observed between both groups (p > 0.05). Interestingly, the results showed that the chewing side had less PI, GI and PPD than non-chewing side. However, gingival recession was significantly higher in the chewing side. The duration of chewing showed a significant effect on PI, PPD, AL, and GR but had no effect on the gingival condition. Likewise, the frequency of chewing showed a significant effect on PPD, AL, and GR, but had no effect on other indices (PI and GI).

Conclusions

The results of this study indicate that khat chewing have a detrimental effect on the periodontium.

Key words:Khat chewing, periodontal health, oral hygiene.

Occurrence and Potential Biological Effects of Amphetamine on Stream Communities

The presence of pharmaceuticals, including illicit drugs in aquatic systems, is a topic of environmental significance because of their global occurrence and potential effects on aquatic ecosystems and human health, but few studies have examined the ecological effects of illicit drugs. We conducted a survey of several drug residues, including the potentially illicit drug amphetamine, at 6 stream sites along an urban to rural gradient in Baltimore, Maryland, U.S.A. We detected numerous drugs, including amphetamine (3 to 630 ng L(-1)), in all stream sites. We examined the fate and ecological effects of amphetamine on biofilm, seston, and aquatic insect communities in artificial streams exposed to an environmentally relevant concentration (1 μg L(-1)) of amphetamine. The amphetamine parent compound decreased in the artificial streams from less than 1 μg L(-1) on day 1 to 0.11 μg L(-1) on day 22. In artificial streams treated with amphetamine, there was up to 45% lower biofilm chlorophyll a per ash-free dry mass, 85% lower biofilm gross primary production, 24% greater seston ash-free dry mass, and 30% lower seston community respiration compared to control streams. Exposing streams to amphetamine also changed the composition of bacterial and diatom communities in biofilms at day 21 and increased cumulative dipteran emergence by 65% and 89% during the first and third weeks of the experiment, respectively. This study demonstrates that amphetamine and other biologically active drugs are present in urban streams and have the potential to affect both structure and function of stream communities.

Qat Chewing and Periodontal Pathogens in Health and Disease: Further Evidence for a Prebiotic-Like Effect

AIM

Qat chewing has been reported to induce subgingival microbial shifts suggestive of prebiotic-like properties. The objective here was to assess the effect of qat chewing on a panel of classical and new putative periopathogens in health and periodontitis.

MATERIALS AND METHODS

40 qat chewers and 40 nonchewers, equally stratified by periodontal health status, were recruited. Taqman, real-time PCR was used to quantify total bacteria, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Parvimonas micra, Filifactor alocis, Synergistetes, and TM7s in pooled subgingival biofilm samples. Differences in microbial parameters between the study groups were analysed using ordinal regression.

RESULTS

In health, the qat chewers harboured significantly lower relative counts of P. gingivalis, T. forsythia, Synergistetes, and TM7s after adjustment for multiple comparisons (P ≤ 0.007). At nominal significance level, they also carried lower counts of TM7s and P. micra (P ≤ 0.05). In periodontitis, the chewers had lower counts of all taxa; however, only T. denticola withstood correction for multiple comparisons (P ≤ 0.0063).

CONCLUSIONS

Qat chewing is associated with lower proportions of periopathogens, particularly in subjects with healthy periodontium, which supports previous reports of its prebiotic-like properties. This potentially beneficial biological effect can be exploited by attempting to isolate the active fraction.

A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems

Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment.

Quantitative analysis of classical and new putative periodontal pathogens in subgingival biofilm: a case-control study

BACKGROUND AND OBJECTIVES

A number of species/phylotypes have been newly implicated as putative periopathogens. The objective of this study was to explore associations among classical and new pathogens in subgingival biofilm and to assess their relative importance to chronic periodontitis.

MATERIAL AND METHODS

Pooled subgingival biofilm samples were obtained from 40 patients with chronic periodontitis and 40 healthy controls. Taqman q-PCR assays were used to determine the absolute and relative counts of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Parvimonas micra, Filifactor alocis, oral Synergistetes and oral TM7s. Microbial associations were assessed using cluster analysis. Different statistical models were used to explore associations between microbial parameters and periodontitis.

RESULTS

The median log and relative counts were lowest for TM7s (4.4 and 0.0016%, respectively) and highest for oral Synergistetes (7.2 and 1.4%, respectively). Oral Synergistetes clustered strongly with the red complex, particularly T. forsythia (100% rescaled similarity). All species/phylotypes except TM7s were significantly associated with periodontitis (Mann-Whitney test; p ≤ 0.005). However, P. gingivalis and F. alocis lost association after adjusting for confounders (ordinal regression). In receiving operator characteristic curve analysis, the log counts of oral Synergistetes were the best markers of periodontitis (82.5% sensitivity and specificity), followed by those of T. forsythia, P. micra and T. denticola. In prediction analysis, however, P. micra was the only microbial predictor of periodontal parameters.

CONCLUSIONS

Oral Synergistetes are presented here as new members of the red complex, with relative importance to periodontitis exceeding that of the classical members. P. micra is shown as an important periodontal pathogen warranting more attention.

Khat Use, PTSD and Psychotic Symptoms among Somali Refugees in Nairobi - A Pilot Study

In East-African and Arab countries, khat leaves are traditionally chewed in social settings. They contain the amphetamine-like alkaloid cathinone. Especially among Somali refugees, khat use has been associated with psychiatric symptoms. We assessed khat-use patterns and psychiatric symptoms among male Somali refugees living in a disadvantaged urban settlement area in Kenya, a large group that has not yet received scientific attention. We wanted to explore consume patterns and study the associations between khat use, traumatic experiences, and psychotic symptoms. Using privileged access sampling, we recruited 33 healthy male khat chewers and 15 comparable non-chewers. Based on extensive preparatory work, we assessed khat use, khat dependence according to DSM-IV, traumatic experiences, posttraumatic stress disorder (PTSD), and psychotic symptoms using standardized diagnostic instruments that had been adapted to the Somali language and culture. Hazardous use patterns like chewing for more than 24 h without interruption were frequently reported. All khat users fulfilled the DSM-IV-criteria for dependence and 85% reported functional khat use, i.e., that khat helps them to forget painful experiences. We found that the studied group was heavily burdened by traumatic events and posttraumatic symptoms. Khat users had experienced more traumatic events and had more often PTSD than non-users. Most khat users experience khat-related psychotic symptoms and in a quarter of them we found true psychotic symptoms. In contrast, among control group members no psychotic symptoms could be detected. We found first evidence for the existence and high prevalence of severely hazardous use patterns, comorbid psychiatric symptoms, and khat use as a self-medication of trauma-consequences among male Somali refugees in urban Kenyan refugee settlements. There is a high burden by psychopathology and adequate community-based interventions urgently need to be developed.

Subgingival periodontal pathogens associated with chronic periodontitis in Yemenis

Background

Subgingival microbial profile associated with periodontitis has been reported to significantly differ by geographical location. The purpose of this study was to assess the association between a panel of putative periodontal bacterial pathogens and chronic periodontitis among Yemenis.

Methods

Subgingival DNA samples were obtained from diseased and healthy sites of 20 non-smoking, moderate to severe chronic periodontitis subjects. Absolute counts (bacterial DNA copies per sample) and relative counts (% total bacteria) of seven periopathogenic species/genera representative of the red and orange complexes were determined using Taqman q-PCR assays.

Results

The q-PCR assays showed excellent linearity (R² > 0.99) and a sensitivity of 100 copies/sample. The detection rate was 100% for all tested species/genera except for P. gingivalis and A. actinomycetemcomitans that were detected at 97.5% and 67.5%, respectively. The median log absolute counts were in the range of 2.41-6.53 copies per sample while median relative counts were in the range of 0.001-0.77%, both being highest for fusobacteria and lowest for A. actinomycetemcomitans. Significant interspecies correlations were observed. Adjusting for multiple comparisons (P≤0.0063), only T. forsythia, T. denticola and P. micra maintained significant association with periodontal destruction. The latter species, however, showed the strongest association and was found in higher proportions at the periodontitis sites across all subjects (3.39 median fold increase). No significant differences were observed for P. gingivalis.

Conclusions

P. micra rather than P. gingivalis appears as a keystone pathogen in this Yemeni Sample. However, these findings need to be validated in a larger-scale study before they can be claimed to represent ethnic variations in pathogens’ association with periodontitis.

Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells

The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behaviour of T. brucei by cell counting and light microscopy. CEF was the most efficient growth inhibitor in comparison to AMR and RMA. Nevertheless, in LNCaP and THP-1 cells, all extracts significantly inhibited tumor growth at 3 μg/mL. All extracts inhibited proliferation of T. brucei cells in a concentration-dependent manner. Microscopic analysis revealed that 95% of the T. brucei cells died when exposed to 33 μg/mL CEF for 3 hrs. Similar results were obtained using 33 μg/mL AMR for 6 hrs. In case of RMA, however, higher concentrations were necessary to obtain similar effects on T. brucei. This demonstrates the antitumor efficacy of these extracts as well as their ability to dampen viability and proliferation of T. brucei, suggesting a common mechanism of action on highly proliferative cells, most probably by targeting cell metabolism.

Classical and novel psychoactive substances: rethinking drug misuse from an evolutionary psychiatric perspective

In this article, ontogenetic and phylogenetic causes of drug abuse and links to human emotional development are considered. Some evolutionary perspectives (e.g. that under certain conditions, consumption of otherwise toxic alkaloids may confer both physical and cultural advantages) are reviewed. As described in the 'mismatch theory', the capacity of the human genome to evolve defences against toxins has been outstripped by the pace of cultural change and technological development, such as purposeful fermentation of alcohol and more recently distillation of alcohol; purification and chemical manipulation of plant alkaloids; and the engineering of entirely novel psychoactive substances (NPS). The functions of the neurobiological substrates that mediate substance misuse and dependence are reviewed. Reasons are given why NPSs present greater cause for concern than plant-derived substances of abuse. We argue that evolutionary biology provides an important orientation for the research agenda in substance misuse.

Qat chewing as an independent risk factor for periodontitis: a cross-sectional study

This study assessed the effect of qat chewing on periodontal health, independent of other risk factors. Four hundred qat chewers and 100 nonchewers (20–50 years) were included. Demographic data and detailed information about chewing and smoking were obtained. Periodontal status was assessed using Community Periodontal Index (CPI) and clinical attachment loss (CAL). The qat chewers were older, included more males and smokers, and had worse oral hygiene but higher education levels; the majority were heavy chewers (mean duration of 14.45 years and frequency of 6.10 days/week). Regression analysis identified age, oral hygiene, education level, and cigarette smoking as independent predictors of periodontal destruction. Adjusted for these, qat chewing showed marginally significant association only with CAL (OR = 4.7; P = 0.049). The chewing sides showed significantly higher scores than the nonchewing sides; however, equal scores on both sides or lower scores on the chewing sides (possibly no or beneficial effect) were still observed in 50% of the chewers. Heavy qat chewing is shown here as an independent risk factor for attachment loss. However, the possibility that the habit may have beneficial effects in a subset of the chewers cannot be excluded. A holistic model that resolves the existing contradiction is presented.

Khat use among HIV voluntary counselling and testing centre clients in Ethiopia

Khat (Catha edulis, a natural stimulant), has been used in Ethiopia for centuries. Over the past few decades, however, its use has dramatically increased, with recent research linking khat use to HIV status. Using qualitative methods, we explored the individual and micro-environmental characteristics of khat use and the social and physical contexts influencing type, acceptability and consequences of khat use. Among khat chewers attending an HIV voluntary counselling and testing centre in Addis Ababa, Ethiopia, we found that chewing typically starts at an early age (15-18 years). The majority of users are young (aged 18-35) and chew for pleasure, primarily in social settings. Over 25 types of khat, with varying effects were reported. Approximately half of the participants perceived khat to enhance sexual desire, while the rest claimed the effect on sexual desire to be the opposite. Alcohol use among chewers was high. Our findings suggest the need for culturally appropriate interventions that highlight the factors associated with khat use and the potential interplay between khat, alcohol and risky sexual behaviour.

Khat (Catha edulis) alters the phenotype and anti-microbial activity of peripheral blood mononuclear cells

AIMS OF STUDY

The habit of khat chewing has been associated with increased risk of systemic and oral disease. Although research has been conducted on the affects of khat on oral epithelial cells, little is known about its influence on immune cells. This study examined the biological effects of khat on the phenotype and function of peripheral blood mononuclear cells (PBMCs).

MATERIAL AND METHODS

Khat-stimulated PBMCs were examined for signs of cytotoxicity, apoptosis and changes in cell surface receptor and cytokine expression. Khat-induced regulation of transcription factors and stress-related factors were examined, as was PBMC phagocytic activity against oral bacteria.

RESULTS

Khat was cytotoxic to PBMC in a dose- and time-dependent manner and cell death was mediated by apoptosis. Khat-treated PBMC showed increased expression of co-stimulatory molecules (CD80, CD86 and MHC II) and pattern recognition receptors (TLR-2, TLR-4 and TREM-1) but secretion of inflammatory cytokines (TNFα, IL-6, CCL5, CXCL8) was inhibited. In contrast, khat induced an increase in the anti-inflammatory cytokine IL-10 as well as IL-2, IFN-γ, FasL and HSP70. These khat-induced alterations were accompanied by increased expression of transcription factors p38 MAPK and HIF-1α, whilst expression of NFκB p65 was inhibited. Although the ability of PBMC to phagocytose dextran and oral bacteria was inhibited, production of reactive oxygen species was increased.

CONCLUSION

These data suggest that khat may severely influence the effectiveness of immune surveillance and anti-microbial capacity of PBMCs.

Introduction to the special issue: the changing use and misuse of khat (Catha edulis)--tradition, trade and tragedy

Within the last decade the hitherto little known psychoactive substance of khat has emerged as a regional and international issue. In the Horn of Africa khat production has spurred an economic boom, but dramatic increases in consumption have raised public health concerns. Given the complexity of the topic spanning multiple academic disciplines and fields of professional practice, the need for a systematic overview is urgent. To facilitate the exchange of information, prompt interdisciplinary research and alert international organisations and governments, the authors organised an international and interdisciplinary khat conference in 2009. This special issue of the Journal of Ethnopharmacology contains articles written by different conference speakers that present the current state of knowledge and the challenges for future research and politics.