Microplastics as carriers of toxic pollutants: Source, transport, and toxicological effects.

Microplastic pollution has emerged as a new environmental concern due to our reliance on plastic. Recent years have seen an upward trend in scholarly interest in the topic of microplastics carrying contaminants; however, the available review studies have largely focused on specific aspects of this issue, such as sorption, transport, and toxicological effects. Consequently, this review synthesizes the state-of-the-art knowledge on these topics by presenting key findings to guide better policy action toward microplastic management. Microplastics have been reported to absorb pollutants such as persistent organic pollutants, heavy metals, and antibiotics, leading to their bioaccumulation in marine and terrestrial ecosystems. Hydrophobic interactions are found to be the predominant sorption mechanism, especially for organic pollutants, although electrostatic forces, van der Waals forces, hydrogen bonding, and pi-pi interactions are also noteworthy. This review reveals that physicochemical properties of microplastics, such as size, structure, and functional groups, and environmental compartment properties, such as pH, temperature, and salinity, influence the sorption of pollutants by microplastic. It has been found that microplastics influence the growth and metabolism of organisms. Inadequate methods for collection and analysis of environmental samples, lack of replication of real-world settings in laboratories, and a lack of understanding of the sorption mechanism and toxicity of microplastics impede current microplastic research. Therefore, future research should focus on filling in these knowledge gaps.

Maternal, Perinatal, and Neonatal Outcomes of COVID-19 Severity in Pregnant Women: A Retrospective Study from Oman.

Objectives: To evaluate the effect of COVID-19 severity on maternal, perinatal, and neonatal outcomes in pregnant women infected with SARS-CoV-2. We also aimed to assess the effect of medical comorbidities on the severity of COVID-19. Methods: A retrospective cohort study was conducted on women who became infected with SARS-CoV-2 during pregnancy and delivered at Sultan Qaboos University Hospital, Oman, from 1 March 2020 to 31 December 2021. Results: A total of 118 pregnant women with COVID-19 and their 118 newborns were included in the study. Mean maternal age was 32.0 years, with 60.2% of women infected in the third trimester. The majority of the participants had mild symptoms. Eleven (9.3%) women had moderate infection needing inpatient care. Six (5.1%) with severe infection were admitted to intensive care unit. The chronic diseases among the participants were hypothyroidism, obesity, sickle cell disease, epilepsy, and diabetes. The mean gestational age at delivery was 37.0 weeks with 20.9% of women delivering by cesarean section out of whom 37.5% had moderate-to-severe COVID-19. The most common complications associated with COVID-19 severity were preterm labor (p =0.002), preeclampsia (p =0.002), and intrauterine fetal death (p =0.089). Of the total 118 newborns, 111 were singletons and six were twins. One fetus died and three singletons were lost to miscarriage. Placental histopathology conducted in 64 patients had no COVID-specific findings in most cases. Conclusions: Most pregnant women with COVID-19 infections had mild symptoms. The majority of women with moderate-to-severe infection were admitted for COVID-19 pneumonia. There was no direct effect of COVID-19 severity in neonatal outcomes or placental histopathology changes.

Beyond Pneumonia: A Rare Case of Pericardial Empyema Caused by Streptococcus pneumoniae.

Purulent pericardial effusion is a rare but potentially deadly condition that demands immediate medical attention. When left untreated, it can have catastrophic consequences. While bacterial infection is the most common cause of this condition, it usually occurs in individuals with weakened immune systems or in those undergoing dialysis or thoracic surgery. This case report presented here is unique as it chronicles the uncommon experience of a 58-year-old male with a normally functioning immune system who suffered from purulent pericardial effusion, endocarditis, and pneumonia, all linked to septic arthritis of his knee caused by Streptococcus pneumoniae. The diagnosis and management of this condition require a swift and comprehensive approach, and any delay in treatment can have dire outcomes. This case highlights the significance of early detection and prompt treatment of purulent pericardial effusion to prevent severe complications and improve patient prognosis.

Nanomaterials as a sustainable choice for treating wastewater.

Wastewater containing toxic substances is a major threat to the health of both aquatic and terrestrial ecosystems. In order to treat wastewater, nanomaterials are currently being studied intensively due to their unprecedented properties. The unique features of nanoparticles are prompting an increasing number of studies into their use in wastewater treatment. Although several studies have been undertaken in recent years, most of them did not focus on some of the nanomaterials that are now often utilized for wastewater treatment. It is essential to investigate the most recent advances in all the types of nanomaterials that are now frequently employed for wastewater treatment. The recent advancements in common nanomaterials used for sustainable wastewater treatment is comprehensively reviewed in this paper. This paper also thoroughly assesses unique features, proper utilization, future prospects, and current limitations of green nanotechnology in wastewater treatment. Zero-valent metal and metal oxide nanoparticles, especially iron oxides were shown to be more effective than traditional carbon nanotubes (CNTs) for recovering heavy metals in wastewater. Iron oxide achieved 75.9% COD (chemical oxygen demand) removal efficiency while titanium oxide (TiO2) achieved 75.5% COD. Iron nanoparticles attained 72.1% methyl blue removal efficiency. However, since only a few types of nanomaterials have been commercialized, it is important to also focus on the economic feasibility of each nanomaterial. This study found that the large surface area, high reactivity, and strong mechanical properties of nanoparticles means they can be considered as a promising option for successful wastewater treatment.

ER Stress in COVID-19 and Parkinson's Disease: In Vitro and In Silico Evidences.

The outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) signifies a serious worldwide concern to public health. Both transcriptome and proteome of SARS-CoV-2-infected cells synergize the progression of infection in host, which may exacerbate symptoms and/or progression of other chronic diseases such as Parkinson's disease (PD). Oxidative stress is a well-known cause of endoplasmic reticulum (ER) stress observed in both SARS-CoV-2 and PD. In the current study, we aimed to explore the influence of PKR-like ER kinase (PERK) stress pathway under SARS-CoV-2-mediated infection and in human cell model of PD. Furthermore, we investigated whether they are interconnected and if the ER stress inhibitors could inhibit cell death and provide cellular protection. To achieve this aim, we have incorporated in silico analysis obtained from gene set enrichment analysis (GSEA), a literature review and laboratory data. The neurotoxin, 6-hydroxy dopamine (6OHDA), was used to mimic the biochemical and neuropathological characteristics of PD by inducing oxidative stress in dopamine-containing neurons differentiated from ReNVM cell line (dDCNs). Furthermore, we explored if ER stress influences activation of caspases-2, -4 and -8 in SARS-CoV-2 and in stressed dDCNs. Our laboratory data using Western blot, immunocytochemistry and 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) analyses indicated that 6OHDA-induced toxicity triggered activation of caspases-2, -4 and -8 in dDCNs. Under SARS-CoV-2 infection of different cell types, GSEA revealed cell-specific sensitivities to oxidative and ER stresses. Cardiomyocytes and type II alveolar epithelial-like cells were more vulnerable to oxidative stress than neural cells. On the other side, only cardiomyocytes activated the unfolded protein response, however, the PERK pathway was operative in both cardiomyocytes and neural cells. In addition, caspase-4 activation by a SARS-CoV-2 was observed via in silico analyses. These results demonstrate that the ER stress pathway under oxidative stress in SARS-CoV-2 and PD are interconnected using diverse pathways. Furthermore, our results using the ER stress inhibitor and caspase specific inhibitors provided cellular protection suggesting that the use of specific inhibitors can provide effective therapeutic approaches for the treatment of COVID-19 and PD.

Comparison of the airway microbiota in children with chronic suppurative lung disease.

RATIONALE: The airway microbiota is important in chronic suppurative lung diseases, such as primary ciliary dyskinesia (PCD) and cystic fibrosis (CF). This comparison has not previously been described but is important because difference between the two diseases may relate to the differing prognoses and lead to pathological insights and potentially, new treatments. OBJECTIVES: To compare the longitudinal development of the airway microbiota in children with PCD to that of CF and relate this to age and clinical status. METHODS: Sixty-two age-matched children (age range 0.5-17 years) with PCD or CF (n=31 in each group) were recruited prospectively and followed for 1.1 years. Throat swabs or sputum as well as clinical information were collected at routine clinical appointments. 16S rRNA gene sequencing was performed. MEASUREMENTS AND MAIN RESULTS: The microbiota was highly individual and more diverse in PCD and differed in community composition when compared with CF. While Streptococcus was the most abundant genus in both conditions, Pseudomonas was more abundant in CF with Haemophilus more abundant in PCD (Padj=0.0005). In PCD only, an inverse relationship was seen in the relative abundance of Streptococcus and Haemophilus with age. CONCLUSIONS: Bacterial community composition differs between children with PCD and those with CF. Pseudomonas is more prevalent in CF and Haemophilus in PCD, at least until infection with Pseudomonas supervenes. Interactions between organisms, particularly members of Haemophilus, Streptococcus and Pseudomonas genera appear important. Study of the interactions between these organisms may lead to new therapies or risk stratification.

Comparative analysis of N95 respirators fit testing with commercially available and in house reagent.

BACKGROUND: Due to COVID-19, thousands of healthcare workers have been affected and have lost their lives in the line of duty. For the protection of healthcare workers, WHO and CDC have made standard guidelines and requirements for PPE use. N95 masks are amongst the most readily used PPE by healthcare professionals and it is highly recommended by OSHA that every make and model of N95 should go through a fit test at least once in a year. METHOD: A total of 30 randomly selected healthcare professionals (who were a regular user of N95 respiratory masks) were subjected to assess in-house (saccharin sodium benzoate) reagent for use for standard qualitative fit testing in our hospital. Threshold testing with the in-house reagent at three different concentrations was performed prior to establish participants' sensitivity to the reagent. After successful completion of threshold testing, fit test was performed on participants wearing an N95 mask. RESULTS: All the participants included in the study passed the sensitivity testing with three concentrations of the reagents, while it was concluded that the concentration of the in-house reagent that was well suited for the sensitivity testing was a concentration of 1g/dl saccharin with 10g/dl sodium benzoate. For fit testing 12g/dl was found to be more appropriate. DISCUSSION: Our study provided a low cost solution to ensure safety of healthcare workers who are regular users of N95 masks following guidelines implemented by OSHA and CDC. CONCLUSION: The in-house test solution prepared was found to be equally sensitive to its commercially available counterpart.

Smartphone Usage Among Doctors in the Clinical Setting in Two Culturally Distinct Countries: Cross-sectional Comparative Study.

BACKGROUND: Smartphones and mobile applications have seen a surge in popularity in recent years, a pattern that has also been reflected in the health care system. Despite increased reliance among clinicians however, limited research has been conducted on the uptake and impact of smartphone usage in medical practice, especially outside the Western world. OBJECTIVE: This study aimed to identify the usage of smartphones and medical apps by doctors in the clinical setting in 2 culturally distinct countries: King Hamad University Hospital (KHUH), Bahrain and Queen Mary Hospital (QMH), Hong Kong. METHODS: A cross-sectional, comparative study was conducted where doctors in both hospitals were asked to take part in a 15-item online survey. The questions were categorized into the following groups: demographics of the study population, ownership and main use of smartphones, number and names of medical apps currently owned, rating usage of smartphones for medical purposes, time spent on a smartphone related to clinical use, clinical reliance on smartphones, and views on further integration of smartphones. The results were then tabulated and analyzed using SPSS Statistics 25 for Mac (IBM Corp Inc, Armonk, NY). RESULTS: A total of 200 doctors were surveyed, with a total of 99.0% (99/100) of the doctors owning a smartphone in both KHUH and QMH; 58% (57/99) and 55% (54/99) of the doctors from KHUH and QMH, respectively, identified communication as their main use of smartphones in the clinical setting (P=.004). Doctors from KHUH were likely to spend more time on medical apps than doctors from QMH (P=.002). According to the overall results of both hospitals, 48% (32/67) of the junior doctors claimed high reliance on smartphones, whereas only 32.3% (41/127) of the senior doctors said the same (P=.03). Of doctors in KHUH and QMH, 78.0% (78/100) and 69.0% (69/100), respectively, either strongly agreed or agreed that smartphones need to be integrated into the clinical setting. In terms of preferences for future apps, 48% (48/100) and 56% (56/100) of the doctors in KHUH and QMH, respectively, agreed that more medical applications need to be created in order to support smartphone use in the clinical setting. CONCLUSIONS: These results suggest a substantial acceptance of smartphones by doctors in the clinical setting. It also elicits the need to establish policies to officially integrate smartphone technology into health care in accordance with ethical guidelines. More emphasis should be placed on creating medical applications that aid health care professionals in attaining their information from accurate sources and also regulate a system to monitor the usage of mobile devices within hospitals to prevent a breach of patient privacy and confidentiality.

COVID-19 and Parkinson's Disease: Shared Inflammatory Pathways Under Oxidative Stress.

The current coronavirus pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a serious global health crisis. It is a major concern for individuals living with chronic disorders such as Parkinson's disease (PD). Increasing evidence suggests an involvement of oxidative stress and contribution of NFκB in the development of both COVID-19 and PD. Although, it is early to identify if SARS-CoV-2 led infection enhances PD complications, it is likely that oxidative stress may exacerbate PD progression in COVID-19 affected individuals and/or vice versa. In the current study, we sought to investigate whether NFκB-associated inflammatory pathways following oxidative stress in SARS-CoV-2 and PD patients are correlated. Toward this goal, we have integrated bioinformatics analysis obtained from Basic Local Alignment Search Tool of Protein Database (BLASTP) search for similarities of SARS-CoV-2 proteins against human proteome, literature review, and laboratory data obtained in a human cell model of PD. A Parkinson's like state was created in 6-hydroxydopamine (6OHDA)-induced differentiated dopamine-containing neurons (dDCNs) obtained from an immortalized human neural progenitor cell line derived from the ventral mesencephalon region of the brain (ReNVM). The results indicated that SARS-CoV-2 infection and 6OHDA-induced toxicity triggered stimulation of caspases-2, -3 and -8 via the NFκB pathway resulting in the death of dDCNs. Furthermore, specific inhibitors for NFκB and studied caspases reduced the death of stressed dDCNs. The findings suggest that knowledge of the selective inhibition of caspases and NFκB activation may contribute to the development of potential therapeutic approaches for the treatment of COVID-19 and PD.

Longitudinal development of the airway microbiota in infants with cystic fibrosis.

The pathogenesis of airway infection in cystic fibrosis (CF) is poorly understood. We performed a longitudinal study coupling clinical information with frequent sampling of the microbiota to identify changes in the airway microbiota in infancy that could underpin deterioration and potentially be targeted therapeutically. Thirty infants with CF diagnosed on newborn screening (NBS) were followed for up to two years. Two hundred and forty one throat swabs were collected as a surrogate for lower airway microbiota (median 35 days between study visits) in the largest longitudinal study of the CF oropharyngeal microbiota. Quantitative PCR and Illumina sequencing of the 16S rRNA bacterial gene were performed. Data analyses were conducted in QIIME and Phyloseq in R. Streptococcus spp. and Haemophilus spp. were the most common genera (55% and 12.5% of reads respectively) and were inversely related. Only beta (between sample) diversity changed with age (Bray Curtis r2 = 0.15, P = 0.03). Staphylococcus and Pseudomonas were rarely detected. These results suggest that Streptococcus spp. and Haemophilus spp., may play an important role in early CF. Whether they are protective against infection with more typical CF micro-organisms, or pathogenic and thus meriting treatment needs to be determined.

Bradycardias are associated with more severe effects on cerebral oxygenation in very preterm infants than in late preterm infants.

BACKGROUND: Commonly the magnitude and frequency of bradycardia is underestimated in the neonatal unit due to the long averaging time used in bedside oximeters. We aimed to assess the frequency and severity of bradycardia in preterm infants using the lowest averaging time (2 s) available on a clinical oximeter, compared with bradycardia detected using electrocardiogram (ECG), and whether bradycardia severity and postmenstrual age affected cerebral oxygenation. METHODS: Preterm infants (10 M/9F) were studied longitudinally at 26-31 (very preterm) and 32-38 weeks (late preterm) postmenstrual age. Heart rate falls calculated from ECG were used to determine mild or moderate/severe (MS) bradycardias. Cerebral tissue oxygenation index (TOI, %) was recorded and fractional tissue oxygen extraction (FTOE) calculated. RESULTS: Of the 615 bradycardias scored using ECG criteria, 10% were not detected by oximetry. TOI falls associated with bradycardias were greater for MS bradycardias compared with Mild for both groups (p < 0.001 for both). The FTOE associated with MS bradycardias was higher for the very preterm compared with the late preterm group (p < 0.001). In very preterm infants 61% of MS and 35% Mild bradycardias were associated with TOI nadirs below 55%. CONCLUSION: Even the most sensitive oximeter setting underestimates bradycardias. The cerebral effect from bradycardias in very preterm infants is more severe than in late preterm infants. Even the mild bradycardias are associated with falls in cerebral oxygenation. Routine NIRS monitoring of cerebral oxygenation in NICUs may increase staff awareness for interventions to reduce the repetitive falls in cerebral oxygenation in preterm infants.

Comparison of the upper and lower airway microbiota in children with chronic lung diseases.

RATIONALE: The lower airway microbiota is important in normal immunological development and chronic lung diseases (CLDs). Young children cannot expectorate and because of the uncertainty whether upper airway samples reflect the lower airway microbiota, there have been few longitudinal paediatric studies to date. OBJECTIVES: To assess whether throat swabs (TS) and cough swabs (CS) are representative of the lower airway microbiota. METHODS: TS, CS, bronchoalveolar lavage and bronchial brushings were prospectively collected from 49 children undergoing fibreoptic bronchoscopy for CLDs. Bacterial DNA was extracted and the 16S rRNA gene V4 region sequenced using the Illumina MiSeq. RESULTS: 5.97 million high quality reads were obtained from 168 samples (47 TS, 37 CS, 42 BALF and 42 bronchial brushings). CS sequenced poorly. At a community level, no difference in alpha diversity (richness, evenness or Shannon Diversity Index) was seen between lower airway samples and TS (P > 0.05). Less than 6.31% of beta diversity variation related to sampling method for TS (P = 0.001). Variation between pathologies and individual patients was greater (20%, 54% respectively P ≤ 0.001) than between TS and lower airway samples. There was strong correlation in the relative abundance of genera between samples (r = 0.78, P < 0.001). Similarity between upper and lower airway samples was observed to be less for individuals where one sample type was dominated by a single organism. CONCLUSIONS: At the community structure level, TS correlate with lower airway samples and distinguish between different CLDs. TS may be a useful sample for the study of the differences in longitudinal changes in the respiratory microbiota between different CLDs. Differences are too great however for TS to be used for clinical decision making.

How to use: bacterial cultures in diagnosing lower respiratory tract infections in cystic fibrosis.

Respiratory infections are the leading cause of morbidity and mortality in cystic fibrosis. Certain bacteria, such as Pseudomonas aeruginosa, are associated with a worse clinical outcome than others, but can be completely eradicated if identified and treated early. The diagnosis of lower respiratory tract infections can be challenging in the non-expectorating patient, in whom upper airway samples, such as cough swabs, are a surrogate for lower airway sampling. However, the results of these often do not fit with the clinical picture, presenting a management dilemma. Frequently, clinicians are faced with a negative culture result in a progressively symptomatic patient and vice versa. When judging the clinical significance of a positive upper airway culture result in an asymptomatic patient, it is important to consider the prognostic significance of the organism cultured. Given that the reported sensitivity of upper airway swabs (which includes throat swabs) is variable, ranging from 35.7% to 71% for Pseudomonas aeruginosa, 50% to 86% for Staphylococcus aureus and 11% to 92% for Haemophilus influenza, upper airway samples may fail to identify lower airway infections. Therefore, in symptomatic children, a repeatedly negative upper airway swab should not be considered as reassuring, and alternative sampling methods, such as induced sputum or bronchoalveolar lavage, should be considered. Here we use some examples of common scenarios to illustrate how best to use bacterial cultures to aid management decisions in cystic fibrosis.

Hyperphosphorylation of CREB in human dopaminergic neurons: a kinetic study of cellular distribution of total CREB and phospho-CREB following oxidative stress.

The neurotoxin, 6-hydroxy dopamine (6-OHDA)-induced oxidative stress causes alterations in intracellular signalling events and activates cellular and molecular mechanisms leading to the degeneration of the dopamine-containing neurons (DCNs). The cyclic-AMP response element-binding protein (CREB) modulates the transcription of mitochondrial and nuclear genes upon phosphorylation. However, oxidative stress disrupts CREB functions and inhibits CREB signalling pathways. We have measured the activities and levels of both total CREB and its phosphorylated form (phospho-CREB) in cytosolic, mitochondrial and nuclear compartments in control (untreated) and stressed (6-OHDA-treated) DCN, differentiated from the ReNVM cell line (dDCN) at 0, 24 and 72 h time points following oxidative stress. Our results indicate that CREB phosphorylation occurs in all three subcellular locations. It further shows significant disruption of the phosphorylation process by 6-OHDA treatment and shows tridirectional trafficking of total CREB and phospho-CREB between cytosol, mitochondria and nucleus following oxidative stress induced by 6-OHDA treatment. In conclusion, our results indicate the presence of specific signalling molecules in all the compartments studied and their involvement in the signal transduction processes, where total CREB and phospho-CREB levels and activities are either upregulated or downregulated to balance each other for their roles.

Caspase-2 and caspase-8 trigger caspase-3 activation following 6-OHDA-induced stress in human dopaminergic neurons differentiated from ReNVM stem cells.

OBJECTIVES: The purpose of the study was to establish a suitable model to study Parkinson's disease (PD) pathogenesis in differentiated dopaminergic neurons (dDCN). The specific aim was to demonstrate the involvement of the caspase family and to identify specific caspases which are activated by 6-hydroxydopamine (6OHD) treatment leading to death of dDCN. METHODS: ReNcell VM cells were differentiated into dDCN and were exposed to 6OHD to induce stress. Western blot (WB) and double immunofluorescent analyses of caspases-2, -3, and -8 were carried out in untreated and 6OHD-treated dDCN. zVADfmk was used to determine if it could inhibit activation of caspases-2, -3, and -8 in dDCN following 6OHD-mediated stress. RESULTS: Our immunofluorescent and WB data showed that 6OHD triggered caspases-2 and -8 activation which in turn activated caspase-3 leading to death of dDCN. Additionally, WB analysis revealed that caspases-2, -3, and -8 activation was reduced by zVADfmk in 6OHD-treated cells. DISCUSSION: The study showed that 6OHD-induced toxicity triggered caspase mediated death of dDCN. This finding is in support of previous studies using different PD model showing that 6OHD can induce caspases-2 and -3 activation through apoptotic pathway and that both caspases can activate caspase-3 in PD. In addition, our results suggest that caspase-2 cause's cell death might be via an indirect NF kappaB route. This study has established a PD model which can provide better insight to PD pathogenesis on a biochemical and molecular level, leading to a better understanding of PD and potential for new treatments.

Incidence, outcome and predictors of bleomycin pulmonary toxicity in a university hospital in Oman.

OBJECTIVES: To determine the incidence and predictors of bleomycin pulmonary toxicity in a university hospital in Oman. METHODS: This retrospective chart review consisted of 46 patients treated with bleomycin-containing regimes at Sultan Qaboos University Hospital in Oman between January 2007 and December 2010. Data regarding patient age, chemotherapy protocol, cumulative bleomycin dose, smoking history, renal function and concurrent use of granulocyte colony stimulating factor (GCSF) were collected from the hospital's electronic database. Analyses were performed using univariate statistical techniques. RESULTS: Of the 46 patients, 22% (n = 10) experienced bleomycin pulmonary toxicity. There was an overall mortality of 4.3% (n = 2; N = 46), with significantly more deaths in the bleomycin pulmonary toxicity group compared to the cohort that did not have bleomycin pulmonary toxicity (20% versus 0%; p = 0.043). The bleomycin pulmonary toxicity group was significantly older compared to the cohort that did not have bleomycin pulmonary toxicity (48 versus 34 years; p = 0.017). Furthermore, adriamycin, bleomycin, vinblastine, dacarbazine, as front-line chemotherapy, was found to have a trend towards increased risk of bleomycin pulmonary toxicity (90% versus 56%; p = 0.067; power = 31%). There did not seem to be significant differences in bleomycin dose (143 versus 149 units; p = 0.727), smoking status (10% versus 14%; p = 1.000) and systolic blood pressure (133 versus 131 mmHg; p = 0.746) between the two study groups. CONCLUSION: This study confirms a relatively high incidence of bleomycin pulmonary toxicity in a tertiary hospital in Oman. Older patients were significantly more likely to suffer bleomycin pulmonary toxicity compared to younger patients.

Is nalidixic acid screening still valid for the detection of reduced susceptibility of fluoroquinolone with Salmonella Typhi?

INTRODUCTION: Considering the limitations of screening with nalidixic acid to detect reduced susceptibility to fluoroquinolones of Salmonella enterica serovar Typhi (S.Typhi) strains, we evaluated the use of a 30 µg nalidixic acid disc screening method in Pakistan. METHODOLOGY: Non duplicate nalidixic acid susceptible S. Typhi isolates (246) from 2003-2008 were retrieved from the Salmonella strain bank. Minimum inhibitory concentrations of ciprofloxacin for all strains were determined by agar dilution and further rechecked by ciprofloxacin E-tests.E. coli ATCC 25922 was used as the control strain. The MIC data for ciprofloxacin were compared with nalidixic acid disk (30 µg) zone diameters. RESULTS: Repeat testing of all S. Typhi isolates with a nalidixic acid (30 µg) disk showed 100% susceptibility with an average zone diameter of 26 mm. Agar dilution testing revealed reduced susceptibility to ciprofloxacin, with MICs of 0.125 µg/ml for three (1.2%) isolates only. Zone sizes of strains with higher MICs were significantly lower than the strains with lower MICs (20 versus 26 mm) (p value < 0.001). CONCLUSION: Estimation of fluoroquinolone MICs on every nalidixic acid susceptible S. Typhi strain is not cost effective in our setting; the proportion of strains with high fluoroquinolone MICs was found to be very low. We recommend periodic fluoroquinolone MIC determination to include all isolates with a nalidixic acid borderline zone (size 20-22 mm).

Local reference ranges of thyroid volume in sudanese normal subjects using ultrasound.

This study aimed to establish a local reference of thyroid volume in Sudanese normal subjects using ultrasound. A total of 103 healthy subjects were studied, 28 (27.18%) females and 75 (72.82%) males. Thyroid volume was estimated using ellipsoid formula. The mean age and range of the subjects was 21.8 (19-29) years; the mean body mass index (BMI) was 22.3 (16.46-26.07) kg/m(2). The overall mean volume ± SD volume of the thyroid gland for both lobes in all the patients studied was 6.44 ± 2.44 mL. The mean volume for both lobes in females and males were 5.78 ± 1.96 mL and 6.69 ± 2.56 mL, respectively. The males' thyroid volume was greater than the females'. The mean volume of the right and left lobes of the thyroid gland in males and females were 3.38 ± 1.37 mL and 3.09 ± 1.24 mL, respectively. The right thyroid lobe volume was greater than the left. The values obtained in this study were lower than those reported from previous studies.