Relationship between vitamin D receptors gene polymorphism and arteriogenic erectile dysfunction.

BACKGROUND: Over the past few decades, a number of studies have linked vitamin-D deficiency with ED (Erectile dysfunction) risk factors. There is a clear correlation between VD (vitamin-D) levels and ED, according to observational and interventional researches that have been reported in the literature. This crucial information encouraged scientists to investigate the impact of VD on erectile function in greater detail. The fact that vitamin D is a component of a healthy penis that begins in early life has just come to light, however there haven't been many research looking at the connection between vitamin D receptor gene polymorphism and erectile dysfunction. OBJECTIVE: To evaluate the relationship between arteriogenic erectile dysfunction and the vitamin D receptor gene polymorphism. SUBJECTS AND METHODS: Between October 2022 and October 2023, at Al-Azhar University Hospitals, 40 patients with arteriogenic ED and 40 healthy controls underwent informed consent, a detailed history, a physical examination, a penile duplex ultrasound and the extraction of peripheral blood to determine the type of polymorphism for each of the vitamin D receptors: FokI, BsmI, ApaI and TaqI by polymerase chain reaction (PCR). RESULTS: There is no statistically significant association between arteriogenic erectile dysfunction and the vitamin D receptors (VDR) gene polymorphisms FokI, BsmI, ApaI and TaqI. CONCLUSION: Since there is no statistically significant association between the polymorphism of the vitamin D receptor (VDR) gene and arteriogenic erectile dysfunction, it is advised to investigate other VDR gene polymorphisms as well as alternative clinical subtypes of erectile dysfunction.

Quality of Life Assessment in Women With Breast Cancer in Nineveh, Iraq.

Background Due to earlier detection and improved treatment and examinations, there has been a rise in the survival rate of patients with breast cancer (BC). It is imperative to examine the health-related quality of life (QoL) of these patients, as it can aid healthcare professionals and authorities in comprehending the variables that influence quality of life. Unfortunately, there is a dearth of information on the subject of women in Nineveh. In Nineveh, a study sought to delve into the quality of life experienced by women undergoing treatment or on follow-up for breast cancer at Mosul Oncology and Nuclear Medicine Hospital. Specifically, researchers wanted to see how age and treatment impacted the QoL of these women. Methods A cross-sectional study was conducted on 212 women with BC. Clinico-pathological-, social-, disease-, and treatment-related characteristics were reviewed. The Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaire was used for assessing QoL in this study. Results The overall FACT-B score was 75.7 (SD=19.99). Around 36.3% (n=77) of women with BC suffered from a lack of energy, and 39% (n=83) could not meet the needs of their families. The mean score of emotional well-being was the lowest among the FACT-B subscales. Patients aged 60 years and older had significantly worse QoL than younger patients (less than 60 years), and patients receiving chemotherapy had poor QoL. During the chemotherapy period, 51.4% (n=77) of patients were bothered by the side effects of treatment; 43.8% (n=65) suffered from pain; 35.3% (n=53) had nausea; and 39.1% (n=58) felt ill. Conclusions Patients with breast carcinoma who are older tend to experience a lower quality of life, according to the findings of a recent study. Interestingly, those who undergo systemic chemotherapy have a worse QoL than their counterparts who complete their chemotherapy cycles. As a result, healthcare providers must offer targeted interventions to improve quality of life, particularly for those who fall into the older age group and those receiving chemotherapy.

Efficacy of Jessener solution versus intralesional steroid in treatment of alopecia areata.

BACKGROUND: Alopecia areata is an autoimmune condition that causes non-scarring hair loss. To date, there is no single cure and treatment remains challenging. OBJECTIVES: To evaluate the efficacy of Jessener solution versus intralesional steroid in treatment of Alopecia Areata. METHODS: This study included 40 patients who presented with multifocal patchy alopecia areata (AA). For each patient, three patches were randomly selected to be treated one with intralesional steroid, another with topical Jessner solution and the third with normal saline. Three sessions were done 3 weeks apart and were followed up for 3 months. Response was assessed clinically and by trichoscope. RESULTS: Fifteen percent of patches coated with Jessner or injected with steroids showed an excellent response while 20% of patches coated with Jessner and 32.5% patches injected with steroids showed a good response. A significant difference was observed between the three modalities of treatment regarding the prognostic score for response (p < 0.001) as patches coated with Jessner and those steroid injected showed a significant higher response rate than patches injected with saline (p < 0.001) while no significant difference was reported between patches either treated with Jessner or steroids (p > 0.05). CONCLUSION: Jessners solution can be a novel and feasible and well tolerated modality of treatment for patients suffering from alopecia areata.

Bilingual teachers' translanguaging practices and ideologies in online classrooms in Saudi Arabia.

Prior studies in translanguaging have investigated its role in education from different perspectives to understand its efficiency, practicality, and how it promotes or challenges educational and societal aims in different multilingual contexts across the world. However, little attention has been paid to translanguaging in universities with a monolingual environment. To cover this gap, the current study examines teachers' online translanguaging practices and ideologies in Saudi Arabia, where the community language is Arabic but English is commonly a medium of instruction in higher education. The study investigated (a) teachers' practices and perspectives toward translanguaging while communicating online with learners; and (b) how, when, and where teachers find translanguaging to be productive. The study adopts a mixed-methods approach to survey 260 bilingual instructors from universities in Saudi Arabia. In addition, 20 teachers' video-recorded sessions are observed to assess the functions of translanguaging during online synchronous instruction. Five of these teachers are interviewed using stimulated-recall techniques. Results show that the teachers mostly hold positive views about translanguaging, considering it productive in helping students understand complex terms and in engaging in communication inside and outside the classroom. The data suggests that bilingual teachers of Arabic and English prefer the new bilingual approach of translanguaging and appear to depend less on the traditional monolingual approach to teaching in multilingual contexts.

Global reports of takotsubo (stress) cardiomyopathy following COVID-19 vaccination: A systematic review and meta-analysis.

Concerns have been raised recently about takotsubo cardiomyopathy (TCM) after receiving COVID-19 vaccines, particularly the messenger RNA (mRNA) vaccines. The goal of this study was to compile case reports to provide a comprehensive overview of takotsubo cardiomyopathy (TCM) associated with COVID-19 vaccines. A systematic literature search was conducted in PubMed, Scopus, Embase, Web of Science, and Google Scholar between 2020 and June 1, 2022. The study included individuals who developed cardiac takotsubo cardiomyopathy from receiving COVID-19 vaccinations. Ten studies, including 10 cases, participated in the current systematic review. The mean age was 61.8 years; 90 % were female, while 10 % were male. 80 % of the patients received the mRNA COVID-19 vaccine, while 20 % received other types. In addition, takotsubo cardiomyopathy (TCM) occurred in 50 % of patients receiving the first dose and another 40 % after the second dose of COVID-19 vaccines. Moreover, the mean number of days to the onset of symptoms was 2.62 days. All cases had an elevated troponin test and abnormal ECG findings. The left ventricular ejection fraction (LVEF) was lower than 50 % in 90 % of patients. In terms of the average length of hospital stay, 50 % stayed for 10.2 days, and all cases recovered from their symptoms. In conclusion, takotsubo (stress) cardiomyopathy (TCM) complications associated with COVID-19 vaccination are rare but can be life-threatening. Chest pain should be considered an alarming symptom, especially in those who have received the first and second doses of the COVID-19 vaccine.

Intelligent breast cancer diagnostic system empowered by deep extreme gradient descent optimization.

Cancer is a manifestation of disorders caused by the changes in the body's cells that go far beyond healthy development as well as stabilization. Breast cancer is a common disease. According to the stats given by the World Health Organization (WHO), 7.8 million women are diagnosed with breast cancer. Breast cancer is the name of the malignant tumor which is normally developed by the cells in the breast. Machine learning (ML) approaches, on the other hand, provide a variety of probabilistic and statistical ways for intelligent systems to learn from prior experiences to recognize patterns in a dataset that can be used, in the future, for decision making. This endeavor aims to build a deep learning-based model for the prediction of breast cancer with a better accuracy. A novel deep extreme gradient descent optimization (DEGDO) has been developed for the breast cancer detection. The proposed model consists of two stages of training and validation. The training phase, in turn, consists of three major layers data acquisition layer, preprocessing layer, and application layer. The data acquisition layer takes the data and passes it to preprocessing layer. In the preprocessing layer, noise and missing values are converted to the normalized which is then fed to the application layer. In application layer, the model is trained with a deep extreme gradient descent optimization technique. The trained model is stored on the server. In the validation phase, it is imported to process the actual data to diagnose. This study has used Wisconsin Breast Cancer Diagnostic dataset to train and test the model. The results obtained by the proposed model outperform many other approaches by attaining 98.73 % accuracy, 99.60% specificity, 99.43% sensitivity, and 99.48% precision.

Global reports of myocarditis following COVID-19 vaccination: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Recent media reports of myocarditis after receiving COVID-19 vaccines, particularly the messenger RNA (mRNA) vaccines, are causing public concern. This review summarizes information from published case series and case reports, emphasizing patient and disease characteristics, investigation, and clinical outcomes, to provide a comprehensive picture of the condition. METHODS: A systematic literature search of PubMed and Google scholar was conducted from inception to April 27, 2022. Individuals who develop myocarditis after receiving the COVID-19 vaccine, regardless of the type of vaccine and dose, were included in the study. RESULTS: Sixty-two studies, including 218 cases, participated in the current systematic review. The median age was 29.2 years; 92.2% were male and 7.8% were female. 72.4% of patients received the Pfizer-BioNTech (BNT162b2) vaccine, 23.8% of patients received the Moderna COVID-19 Vaccine (mRNA-1273), and the rest of the 3.5% received other types of COVID-19 vaccine. Furthermore, most myocarditis cases (82.1%) occurred after the second vaccine dose, after a median time interval of 3.5 days. The most frequently reported symptoms were chest pain, myalgia/body aches and fever. Troponin levels were consistently elevated in 98.6% of patients. The admission ECG was abnormal in 88.5% of cases, and the left LVEF was lower than 50% in 21.5% of cases. Most patients (92.6%) resolved symptoms and recovered, and only three patients died. CONCLUSION: These findings may help public health policy to consider myocarditis in the context of the benefits of COVID-19 vaccination.

Breast Cancer Prediction Empowered with Fine-Tuning.

In the world, in the past recent five years, breast cancer is diagnosed about 7.8 million women's and making it the most widespread cancer, and it is the second major reason for women's death. So, early prevention and diagnosis systems of breast cancer could be more helpful and significant. Neural networks can extract multiple features automatically and perform predictions on breast cancer. There is a need for several labeled images to train neural networks which is a nonconventional method for some types of data images such as breast magnetic resonance imaging (MRI) images. So, there is only one significant solution for this query is to apply fine-tuning in the neural network. In this paper, we proposed a fine-tuning model using AlexNet in the neural network to extract features from breast cancer images for training purposes. So, in the proposed model, we updated the first and last three layers of AlexNet to detect the normal and abnormal regions of breast cancer. The proposed model is more efficient and significant because, during the training and testing process, the proposed model achieves higher accuracy 98.44% and 98.1% of training and testing, respectively. So, this study shows that the use of fine-tuning in the neural network can detect breast cancer using MRI images and train a neural network classifier by feature extraction using the proposed model is faster and more efficient.

Visual Outcomes of Microkeratome-Assisted Anterior Lamellar Keratoplasty in Keratoconus: 5-Year Results.

Purpose: To report 5-year results of microkeratome-assisted anterior lamellar keratoplasty (MK-ALK) in cases of keratoconus. Methods: Patients with advanced keratoconus and the thinnest corneal location 300 µ or more were recruited. A Carriazo-Barraquer microkeratome was used to remove a 200-µ cap from the recipient cornea, and to prepare a 300-µ anterior stromal graft from a donor cornea. A full-thickness crescentic incision was made in the posterior stromal recipient bed using a 6.5-mm suction trephine. The donor was sutured to the recipient bed using interrupted nylon sutures. The minimum follow-up was five years. Results: Twelve eyes of 12 patients were included. The mean age was 26 ± 8 years. None of the patients required conversion to penetrating keratoplasty. Mean logMAR uncorrected and best spectacle-corrected visual acuity, respectively, improved from 1.56 ± 0.24 and 1.18 ± 0.32 preoperatively, to 0.63 ± 0.38 and 0.18 ± 0.12, five years after surgery (P=0.001for both). There was also a statistically significant reduction of mean manifest spherical equivalent, refractive cylinder, and mean keratometry readings. Posterior stromal striations occurred in all patients immediately after surgery but resolved after a maximum of 3 months. At five-years, anterior segment optical coherence tomography revealed a clear interface in all cases and a mean graft thickness of 328 ± 27 µ. Conclusion: MK-ALK is a safe and effective procedure for advanced keratoconus. Where feasible, it may be the best choice for patients at high risk of poor outcomes with penetrating keratoplasty, such as young patients with atopic keratoconjunctivitis or Down's syndrome.

Rainfall Prediction System Using Machine Learning Fusion for Smart Cities.

Precipitation in any form-such as rain, snow, and hail-can affect day-to-day outdoor activities. Rainfall prediction is one of the challenging tasks in weather forecasting process. Accurate rainfall prediction is now more difficult than before due to the extreme climate variations. Machine learning techniques can predict rainfall by extracting hidden patterns from historical weather data. Selection of an appropriate classification technique for prediction is a difficult job. This research proposes a novel real-time rainfall prediction system for smart cities using a machine learning fusion technique. The proposed framework uses four widely used supervised machine learning techniques, i.e., decision tree, Naïve Bayes, K-nearest neighbors, and support vector machines. For effective prediction of rainfall, the technique of fuzzy logic is incorporated in the framework to integrate the predictive accuracies of the machine learning techniques, also known as fusion. For prediction, 12 years of historical weather data (2005 to 2017) for the city of Lahore is considered. Pre-processing tasks such as cleaning and normalization were performed on the dataset before the classification process. The results reflect that the proposed machine learning fusion-based framework outperforms other models.

Global reports of takotsubo (stress) cardiomyopathy following COVID-19 vaccination: First systematic review and meta-analysis

Concerns have been raised recently about takotsubo cardiomyopathy (TCM) after receiving COVID-19 vaccines, particularly the messenger RNA (mRNA) vaccines. The goal of this study was to compile case reports to provide a comprehensive overview of takotsubo cardiomyopathy (TCM) associated with COVID-19 vaccines. A systematic literature search was conducted in PubMed, Scopus, Embase, Web of Science, and Google Scholar between 2020 and June 1, 2022. The study included individuals who developed cardiac takotsubo cardiomyopathy from receiving COVID-19 vaccinations. Ten studies, including 10 cases, participated in the current systematic review. The mean age was 61.8 years; 90% were female, while 10% were male. 80% of the patients received the mRNA COVID-19 vaccine, while 20% received other types. In addition, takotsubo cardiomyopathy (TCM) occurred in 50% of patients receiving the first dose and another 40% after the second dose of COVID-19 vaccines. Moreover, the mean number of days to the onset of symptoms was 2.62 days. All cases had an elevated troponin test and abnormal ECG findings. The left ventricular ejection fraction (LVEF) was lower than 50% in 90% of patients. In terms of the average length of hospital stay, 50% stayed for 10.2 days, and all cases recovered from their symptoms. In conclusion, takotsubo (stress) cardiomyopathy (TCM) complications associated with COVID-19 vaccination are rare but can be life-threatening. Chest pain should be considered an alarming symptom, especially in those who have received the first and second doses of the COVID-19 vaccine.

Global Reports of Myocarditis Following COVID-19 Vaccination: A Systematic Review and Meta-Analysis

In December 2020, the FDA granted emergency approval to Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273) COVID-19 vaccines. There have been recent media reports of myocarditis after receiving COVID-19 vaccines, particularly the messenger RNA (mRNA) vaccines, causing public concern. This review summarizes information from published case series and case reports, with a strong emphasis on reporting patient and disease characteristics, investigation, and clinical outcome, to provide a comprehensive picture of the condition. Forty studies, including 147 cases, participated in this systematic review. The median age was 28.9 years; 93.9% were male and 6.1% were female. 72.1% of patients received the Pfizer-BioNTech (BNT162b2) vaccine, 24.5% of patients received the Moderna COVID-19 Vaccine (mRNA-1273), and the rest of the 3.3% received other types of vaccines. Furthermore, most myocarditis cases (87.1%) occurred after the second vaccine dose, after a median time interval of 3.3 days. The most frequently reported symptoms were chest pain, myalgia/body aches and fever. Troponin levels were consistently elevated in 98.6%. The admission ECG was abnormal in 88.5% of cases, and the left LVEF was lower than 50% in 26.5% of cases. The vast majority of patients (93.2%) resolved symptoms and recovered, and only 3 patients died. These findings may help public health policy to consider myocarditis in the context of the benefits of COVID-19 vaccination as well as to assess the cardiac condition before the choice of vaccine, which is offered to male adults. In addition, it must be carefully weighed against the very substantial benefit of vaccination.

Comparison between 308-nm excimer light alone versus 308-nm excimer light and platelet-rich plasma in the treatment for localized vitiligo.

BACKGROUND: Monochromatic excimer light (MEL) is a safe and effective treatment for localized stable vitiligo. Previous reports of the combination of platelet-rich plasma (PRP) with narrowband ultraviolet B (NB-UVB) or excimer laser yielded conflicting results. AIMS: This prospective, self-controlled, randomized, comparative study aimed to assess whether the addition of PRP to MEL therapy would be of an additive benefit in the treatment for localized stable vitiligo. Patients/Methods The current study included 36 patients with at least 2 more or less symmetrical patches of localized stable vitiligo (72 patches). For each patient, each of the 2 vitiligo patches was randomly assigned to receive either MEL therapy (twice weekly) with bi-weekly intradermal PRP (group A) or MEL therapy alone (group B) for a maximum of 4 months or till complete repigmentation. The degree of repigmentation was categorized as absent (0%), poor (1-25%), moderate (26-50%), good (51-75%), or excellent (>75%). Patients were asked about their level of satisfaction (not satisfied at all, partially satisfied, satisfied, or completely satisfied). Side effects were recorded, and follow-up for 3 months was done. RESULTS: No statistically significant difference was observed between the 2 groups regarding the degree of repigmentation, the patients' level of satisfaction, and the frequency of side effects (p = 0.504, 0.490, and 0.912, respectively). At the end of the follow-up period, recurrence was observed in only 3 patients. CONCLUSIONS: The current study showed no statistically significant difference between using MEL alone or with intradermal PRP in the treatment for localized stable vitiligo.

Isolation and characterization of vancomycin and erythromycin resistant Staphylococcus aureus from Cairo, Egypt

Aims@#Staphylococcus aureus is an important opportunistic human pathogen. The emergence of macrolide and vancomycin resistant S. aureus is of great concern for treatment of S. aureus infections. The current study aimed to investigate the pattern of antibiotic resistance in S. aureus clinical isolates recovered from El Boos Students’ hospital in Cairo, Egypt.@*Methodology and results@#Sixty unduplicated S. aureus isolates were recovered from El Boos Students’ hospital in Cairo, Egypt for 11 months period. The antibiotic susceptibility test revealed that all isolates were resistant to eleven antibiotics, but only 49 S. aureus isolates were resistant to cefoxitin. The minimum inhibitory concentrations (MIC) of both erythromycin and vancomycin were determined by broth microdilution method. Two methicillin resistant S. aureus (MRSA) isolates showing tolerance to both erythromycin and vancomycin at high concentration were selected for further characterization. One isolate was recovered from eye infection and had MIC at 256 µg/mL of both erythromycin and vancomycin. While another isolate was recovered from throat infection and had MIC of erythromycin and vancomycin up till 512 µg/mL. The presence of resistance genes (ermA, ermB, ermC, mef, msrA, vanA and vanB) were confirmed by polymerase chain reaction (PCR). Both MRSA isolates carried all tested resistance genes.@*Conclusion, significance and impact of study@#This study highlights the concern of presence of multidrug-resistant S. aureus which showed resistance to high concentrations of erythromycin, vancomycin and carried ermA, ermB, ermC, mef, msrA, vanA and vanB genes, therefore imposes risk of failure to treat such infections.

Accounting for Global COVID-19 Diffusion Patterns, January-April 2020.

Key factors in modeling a pandemic and guiding policy-making include mortality rates associated with infections; the ability of government policies, medical systems, and society to adapt to the changing dynamics of a pandemic; and institutional and demographic characteristics affecting citizens' perceptions and behavioral responses to stringent policies. This paper traces the cross-country associations between COVID-19 mortality, policy interventions aimed at limiting social contact, and their interactions with institutional and demographic characteristics. We document that, with a lag, more stringent pandemic policies were associated with lower mortality growth rates. The association between stricter pandemic policies and lower future mortality growth is more pronounced in countries with a greater proportion of the elderly population and urban population, greater democratic freedoms, and larger international travel flows. Countries with greater policy stringency in place prior to the first death realized lower peak mortality rates and exhibited lower durations to the first mortality peak. In contrast, countries with higher initial mobility saw higher peak mortality rates in the first phase of the pandemic, and countries with a larger elderly population, a greater share of employees in vulnerable occupations, and a higher level of democracy took longer to reach their peak mortalities. Our results suggest that policy interventions are effective at slowing the geometric pattern of mortality growth, reducing the peak mortality, and shortening the duration to the first peak. We also shed light on the importance of institutional and demographic characteristics in guiding policy-making for future waves of the pandemic.

Aberrant Expression of Immune-related MicroRNAs in Pediatric Patients with Asthma.

MicroRNAs (miRNAs) have been implicated as regulatory molecules that could play a considerable role in the pathogenesis of different diseases including asthma. This work aims at exploring the role of miR-146a and miR- 106b in the pathogenesis of asthma and their association with asthma severity, IgE, and inflammatory cytokines in asthmatic children. Thirty asthmatic children and twenty age-matched healthy children aged 4-17 years old were enrolled. Expression of plasma miR-146a and miR-106b was measured using quantitative real-time PCR. Plasma levels of interleukin-5 (IL-5) and interleukin-13 (IL-13) were assessed using ELISA. Lung functions were measured by Spirometry. MiR-146a and miR-106b were significantly over-expressed in asthmatic children compared to healthy children. A significant positive correlation between total IgE and both miR-146a and miR-106b was found while no significant correlation could be detected between these miRNAs and asthma severity in asthmatic children. Plasma levels of IL-5 and IL-13 were non-significantly higher in asthmatic children compared to healthy children, and there was no significant correlation between them and both miR-146a and miR-106b expressions in the asthmatic children. The aberrant expression of immune-related miRNAs (miR-146a and miR-106b) and inflammatory cytokines (IL-5 and IL-13) among asthmatic children suggest their probable role in asthma pathogenesis.

Intense pulsed light versus benzoyl peroxide 5% gel in treatment of acne vulgaris.

Acne is a common disorder affecting the pilosebaceous unit. Despite many advances in the treatments of acne vulgaris the best option is still controversial as the pathogenesis of acne is rather complex, necessitating various combination therapies. The objective of this study is to compare the clinical efficacy of intense pulsed light therapy (IPL) versus benzoyl peroxide 5% for the treatment of inflammatory acne. Fifty patients of both sexes, (15 males and 35 females) aged (18-27 years), with mild-to-severe acne and Fitzpatrick skin phototype IV were enrolled in this study. The patients were equally divided into two groups. The first group was treated by benzoyl peroxide while the second group was treated by IPL. For both therapies, patients experienced a significant reduction in the mean of the inflammatory lesion counts over the treatment period. Comparing the effects of both therapies, BP produced better results than IPL. The difference in the results was statistically significant at the midpoint of the study. However, this difference was insignificant at the end of study. Treatment with both benzoyl peroxide and IPL resulted in considerable improvement of the acne after 5 weeks of treatment. Comparing the effects of both therapies, BP produced better results than IPL. The difference in the results was statistically significant at the midpoint of the study. However, this difference was insignificant at the end of study.

Characterization of signaling pathways coupled to melatonin receptors in gastrointestinal smooth muscle.

Melatonin, a close derivative of serotonin, is involved in physiological regulation of circadian rhythms. In the gastrointestinal (GI) system, melatonin exhibits endocrine, paracrine and autocrine actions and is implicated in the regulation of GI motility. However, it is not known whether melatonin can also act directly on GI smooth muscle cells. The aim of the present study was to determine the expression of melatonin receptors in smooth muscle and identify their signaling pathways. MT1, but not MT2 receptors are expressed in freshly dispersed and cultured gastric smooth muscle cells. Melatonin selectively activated Gq and stimulated phosphoinositide (PI) hydrolysis in freshly dispersed and cultured muscle cells. PI hydrolysis was blocked by the expression of Gq, but not Gi minigene in cultured muscle cells. Melatonin also caused rapid increase in cytosolic Ca(2+) as determined by epifluorescence microscopy in fura-2 loaded single smooth muscle cells, and induced rapid contraction. Melatonin-induced PI hydrolysis and contraction were blocked by a non-selective MT1/MT2 antagonist luzindole (1 µM), but not by a selective MT2 antagonist 4P-PDOT (100 nM), and by the PLC inhibitor U73122. MT2 selective agonist IIK7 (100 nM) had no effect on PI hydrolysis and contraction. We conclude that rabbit gastric smooth muscle cells express melatonin MT1 receptors coupled to Gq. Activation of these receptors causes stimulation of PI hydrolysis and increase in cytosolic Ca(2+), and elicits muscle contraction.