Antimicrobial Resistance Profile in ICU Patients Across India: A Multicenter, Retrospective, Observational Study.

Background The pattern of antimicrobial resistance (AMR) changes with time and varies in countries and between hospitals within the same country. Physicians might thus benefit from information on regional resistance patterns of clinically significant bacterial isolates when deciding on the best empirical treatment. Numerous nosocomial infections are caused by multidrug-resistant (MDR) strains, notably methicillin-resistant Staphylococcus aureus (MRSA) strains, which are also linked to higher morbidity and death. Aim Evaluation of AMR profile in intensive care unit (ICU) patients of multiple tertiary care centers across India. Methods This was a multicenter, retrospective study based on electronic laboratory records of microbial isolates from clinical specimens from ICUs analyzed at microbiology laboratories of identified hospitals. Data of invasive sample records was collected from Microbiology labs of the identified hospitals within India and were aligned to WHO 5 Net standard reporting and as per Clinical & Laboratory Standards Institute (CLSI-2014) Guidelines for assessment. Data from 21556 samples were collected retrospectively from December 2021 to January 2010. Antibiotic susceptibility testing was done by using both the Kirby Baur disk diffusion method and the automated method (using the Vitek 2 compact system) as per CLSI (2014) guidelines. Results Of 21,556 enrolled patients, the majority (54.12%) were males and adults (62.07%). The median age was 58 years. Of 815 gram-positive bacteria reports, the commonest were S. aureus (552, 67.73%), Coagulase-negative Staphylococci (107, 13.13%), and Enterococcus spp. (105, 12.88%). For Coagulase-negative Staphylococci-positive samples, resistance was to penicillin (79, 73.83%), and erythromycin (73, 68.22%); and for S. aureus was to ciprofloxacin (361, 65.4%), and erythromycin (315,57.07%). Enterococcus spp. showed maximum resistance to erythromycin (73, 69.52%), followed by ampicillin, ciprofloxacin (68,64.76% each). Of 4,183 gram-negative bacteria reports, the commonest were Klebsiella pneumoniae (1,531, 36.6%), Escherichia coli (1,269, 30.34%), and Acinetobacter spp. (589, 14.08%), Pseudomonas aeruginosa (438, 14.08%), other Klebsiella spp. (174, 4.16%) and Enterobacter spp. (161, 3.85%). K. pneumoniae showed resistance to ciprofloxacin (1,001, 65.38%). E. coli showed resistance to ampicillin (918, 72.34%), and ciprofloxacin (798,62.88%); and Acinetobacter spp. to ceftazidime (525, 89.13%), and ciprofloxacin (507, 86.08%), while P. aeruginosa showed resistance to imipenem (234, 53.42%). Enterobacter spp. showed resistance to cefotaxime (129, 80.12%). MRSA samples showed resistance to phenoxymethylpenicillin (188, 35.54%) and benzylpenicillin (178, 33.46%). Conclusion Gram-negative bacteria were more common than gram-positive bacteria in causing antibiotic-resistant infections in ICU, with beta-lactams, fluoroquinolones, macrolides, and cephalosporins showing varied percentages of resistance. Fluoroquinolones, macrolides, and penicillin were noted to be highly resistant against gram-positive species. This indicates that evaluation based on MDR and antibiotic consumption patterns is imperative.

Awareness and Safety of COVID-19 Vaccination in Pregnancy.

Background: COVID-19 vaccines are safe in pregnancy, as they do not contain a live attenuated virus. Mass vaccination is a key to control the pandemic. Neonates have been shown to be susceptible to severe illness, so maternal vaccination is important to provide neonatal vaccination. Methods: The present study was conducted for a period of one year from November 21, 2021 to October 2O, 2022 at the Department of Obstetrics and Gynecology A.S.J.S.A.T.D.S. medical college, Fatehpur. It was a hospital-based cross-sectional study. This study aimed to investigate the efficacy, safety, attitude, side effect and maternal neonatal outcome of COVID-19 vaccination among pregnant women. Results: Out of 3320 pregnant women delivered, only 1170 (35.24%) received at least one dose of COVID-19 vaccine. 69.23% were unaware of the type of COVID-19 vaccine. 66.15% were vaccinated for both the doses before pregnancy. 12.30% of women had taken only the first dose of COVID vaccine before pregnancy. Majority had fever with chills after the first dose. Fatigue was most common side effect after second dose, and no one had any rash or allergic reaction. 56.15% delivered vaginally, 37.69% had LSCS for different obstetric indications, and 6.15% had instrumental delivery. During the antenatal period, 38.46% developed anemia, 11.54% had preterm labor, 2.05% had gestational diabetes, 2.30% developed preeclampsia, and 3.85% developed hypothyroidism. 3.07% prolonged labor in intrapartum period, and 6.92% women developed PPH. 50.77% newborns were between 2.5 and 2.9 kg, and majority 71.54% newborns had an APGAR score of 7 or more at 5 minutes. 14.62% newborns had meconium aspiration syndrome, 3.84% had respiratory distress syndrome, and 20.34% needed NICU admission more than 24 hours. Conclusion: Available data do not support increased risk of adverse outcome following COVID-19 vaccination. We recommend vaccination during pregnancy as benefit outweigh the potential risk. Supplementary Information: The online version contains supplementary material available at 10.1007/s13224-023-01918-w.

Recommendations for measuring and standardizing light for laboratory mammals to improve welfare and reproducibility in animal research.

Light enables vision and exerts widespread effects on physiology and behavior, including regulating circadian rhythms, sleep, hormone synthesis, affective state, and cognitive processes. Appropriate lighting in animal facilities may support welfare and ensure that animals enter experiments in an appropriate physiological and behavioral state. Furthermore, proper consideration of light during experimentation is important both when it is explicitly employed as an independent variable and as a general feature of the environment. This Consensus View discusses metrics to use for the quantification of light appropriate for nonhuman mammals and their application to improve animal welfare and the quality of animal research. It provides methods for measuring these metrics, practical guidance for their implementation in husbandry and experimentation, and quantitative guidance on appropriate light exposure for laboratory mammals. The guidance provided has the potential to improve data quality and contribute to reduction and refinement, helping to ensure more ethical animal use.

A Comparative Analysis of Nondescent Vaginal Hysterectomy, Laparoscopy-Assisted Vaginal Hysterectomy, and Total Laparoscopic Hysterectomy for Benign Uterine Diseases at a Rural Tertiary Care Center.

Objectives: The aim of this study was to compare operative data and postoperative complications among nondescent vaginal hysterectomy (NDVH), laparoscopy-assisted vaginal hysterectomy (LAVH), and total laparoscopic hysterectomy (TLH) at a rural tertiary care center. Materials and Methods: This is a prospective analytical study, of 145 hysterectomies for benign conditions with or without salpingo-oophorectomy in women from 30 to 60 years, over 3 years from January 2016 to December 2019, with 60 cases of NDVH, 46 cases of LAVH, and 39 cases of TLH. The three groups were compared intraoperatively in terms of blood loss, operating time, and intraoperative complications and postoperative complications and postoperative duration of hospital stay. Results: There was no significant difference between the three groups in terms of age, parity, body mass index, and indications for hysterectomies. The mean operative time was significantly shorter (P = 0.000) in the NDVH group (54.67 ± 15.67 min) as compared to the LAVH (102.45 ± 10.53 min) and TLH (126.79 ± 8.7 min) groups. Intraoperative blood loss was greater (P = 0.000) in the TLH group (111.025 mL ± 20.8) as compared to the NDVH (59.50 mL ± 16.7) and LAVH (91.85 mL ± 10.66) groups. The intraoperative complications and postoperative complications were higher in the TLH group as compared to the LAVH and NDVH groups. The duration of hospital stay was almost similar in all the groups. Conclusion: NDVH may be the preferred approach for experienced surgeons, as it is less time-consuming, has a small amount of blood loss, and is a scarless surgery, whereas LAVH and TLH may be the preferred approaches in the cases of presence of adnexal masses and adhesions or whenever salpingo-oophorectomy is indicated.

Maternal and Perinatal Outcomes of COVID-19-Positive Pregnant Women.

Background The risks of adverse maternal and perinatal outcomes are not very clear in coronavirus disease 2019 (COVID-19)-positive pregnant women. Therefore, this study aimed to determine the maternal and fetal outcomes in COVID-19-positive pregnancies. Methodology This prospective, cohort study was conducted in a tertiary care center over the period of one year. The study group comprised pregnant patients who presented with COVID-19 in the first and second waves of the pandemic. Maternal symptoms due to COVID-19 infection, comorbidities, number of admissions to the intensive care unit (ICU), and maternal mortality were noted for every patient. Perinatal outcomes were recorded in the form of intrauterine growth retardation (IUGR), mode of delivery, preterm deliveries, birth weight of newborns, neonatal intensive care unit (NICU) admissions, and neonatal mortality. Data analysis was done in the form of a variable percentage and mean ± standard deviation (SD). Results COVID-19-positive pregnant patients were mostly asymptomatic (48.07%). Term deliveries (37-40 weeks) were seen in 44 (89.8%) patients. The percentage of normal vaginal delivery was 74% and cesarean section was 24%. Out of 52 patients, two (3.8%) patients were admitted to the high dependency unit (HDU), one (1.9%) patient was admitted to the ICU, and 49 (94.3%) patients were in the isolation ward. Of the 49 live births, four (8.16%) newborns were admitted to the NICU. No neonatal death was recorded. Conclusions In this study, COVID-19-pregnant women were mostly asymptomatic. Neonates of COVID-19-infected women also mostly tested COVID-19 negative. More studies are needed with larger sample sizes to determine the effect of COVID-19 infection in pregnant women and neonates.

Acrylamide content in starch based commercial foods by using high performance liquid chromatography and its association with browning index.

The harmful effects of acrylamide (AA) are a major health concern for human beings. To find out the levels of AA content in commercial food products, 43 samples representing 3 important product categories (French fries, bakery biscuits, and branded biscuits) were procured from the local market in Allahabad, India. An assay of AA was done using HPLC-DAD. The LOD and LOQ for AA were 3.733 and 11.045 ng/µl, respectively. The AA recovery from ten standard solutions was 100.6 percent, indicating good extraction efficiency. Level of AA ranged between 144.35 and 781.17 µg/kg, 126.33-664.90 µg/kg, and 825.96-1143.15 µg/kg, in branded biscuits, bakery biscuits, and French fries, respectively. A strong and positive correlation of AA was found with HMF, a* value, BI and negatively with ΔE (P ≤ 0.01). It is concluded that a high browning index is significantly associated with AA content and can be used as a screening food to reduce the intake of AA in the diet.

The Study of Prevalence and Pattern of Thyroid Disorder in Pregnant Women: A Prospective Study.

Background The most frequent thyroid disorder in pregnancy is maternal hypothyroidism. The geographical variation in the prevalence of hypothyroidism during pregnancy is very wide and ranges from 2.5% to 11%. The prevalence of hypothyroidism is more in Asian countries as compared to western countries. Thus, this study was conducted to find out the prevalence of thyroid disorder in pregnancy at our center. Methods The present study was conducted in the Department of Physiology in collaboration with the Department of Obstetrics & Gynecology, Index Medical College, Hospital and Research Center, Indore, MP, India over a period of one and a half years from October 2018 to March 2020. It was a cross-sectional study including 865 pregnant women. The patients' demographic profile was noted in all cases. A detailed history and thorough examination were done in all cases. Serum thyroid-stimulating hormone (TSH), Free T3, and Free T4 (FT3 and FT4) were done along with routine blood investigations as per The Federation of Obstetric and Gynaecological Societies of India-Indian College of Obstetricians and Gynaecologists (FOGSI-ICOG) good clinical practice recommendation. Results In this study, the prevalence of thyroid dysfunction was 10.4%. Of these 90 patients with thyroid dysfunction, subclinical and overt hypothyroidism was found in 5.50% and 0.92%, respectively, whereas subclinical and overt hyperthyroidism was observed in 3.12% and 0.81% pregnant females, respectively. A significant association was found between thyroid dysfunction and maternal age, BMI, parity, and education. Conclusions The prevalence of thyroid dysfunction was 10.4% in this study. Hypothyroidism was more common than hyperthyroidism and subclinical thyroid disorders were more common than overt thyroid disorders in pregnancy. Therefore, we should include thyroid function tests with other routine investigations during pregnancy to detect thyroid dysfunction.

Comparison of the Efficacy of the Cartridge-Based Nucleic Amplification (CBNAAT)/Xpert Test and Histology of Genital Tissues in Diagnosing Female Genital Tuberculosis.

Background Diagnosing female genital tuberculosis (FGTB) is very difficult by routine laboratory investigations. Collecting tissues from genital structures, especially from tubes for histology, is impossible. The cartridge-based nucleic amplification (CBNAAT)/Xpert RIF test is a new polymerase chain reaction (PCR)-based method that is quick and may diagnose FGTB from any tissue type; however, it should not be contaminated with blood. This study was conducted to compare the efficacy of CBNAAT and the histology of genital tissue in suspected cases. Materials and methods This was a prospective study of the diagnostic efficacy of 91 cases of suspected FGTB randomly selected from March 2018 to September 2019 at a rural tertiary care center. Endometrial tissue collected in 86 patients (59 infertility, 27 menstrual irregularities) and tubal/peritoneal tissue from hysterectomy or laparotomy specimens of five participants who underwent surgery were sent for histopathological analysis and CBNAAT and the results were evaluated and compared. Results There were 59 (64.83%) and 32 (35.2%) cases of infertility and menstrual irregularities, respectively. Primary infertility (38; 41.75%) was the most common complaint. Endometrial biopsies (EB) of two (2.23%) cases were found positive for tuberculosis (TB) both on histopathological examination (HPE) and CBNAAT. In addition, both patients had primary infertility. Of the 32 cases with menstrual abnormalities (27 EB and three tubal tissue, two peritoneal and nodular tissue), none were found to be positive for TB on HPE or CBNAAT. A highly significant association was found between histopathology and CBNAAT (p<0.0001) in the endometrial tissue of infertile patients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100% for CBNAAT, with reference to histopathology. Conclusion We recommend CBNAAT for the early detection of FGTB, with the added advantage of early results, minimal technical expertise, and detection of drug-resistant tuberculosis (TB).

Diagnostic Role of Calretinin in Suspicious Cases of Hirschsprung's Disease.

Background Hirschsprung's disease (HD) is a developmental disorder of the intrinsic component of the enteric nervous system. It is characterized by the absence of ganglion cells in the myenteric and submucosal plexus. Histopathological diagnosis becomes difficult many times due to submucosal ganglionic cells are not easily identifiable. Aims and objective The aim of this study was to examine the clinical and histopathological features of HD and to establish the utility of calretinin staining to diagnose the case of suspicious HD. Materials and methods After taking necessary informed consent, we studied 41 cases in which clinical suspicion of HD had been made, in a study duration of three years (July 2017-June 2020). Open biopsies were taken from spastic segment, transition zone and dilated segment. Histopathological diagnosis had been made in three categories: HD, no Hirschsprung's disease (NHD) and suspicion of HD. Post histopathological diagnosis calretinin immunohistochemistry (IHC) was applied to all cases and interpretations were noted. Results On the basis of histopathological findings, 25 cases were diagnosed as HD, nine cases were marked for suspicion for HD and seven cases as NHD. After evaluating calretinin IHC on the suspicious case, total of 30 cases were confirmed as HD while the remaining 11 cases were confirmed as NHD. Twenty-four patients of HD were males while the remaining six cases were females. The age of patients ranged from four days to 10 years. Median age six days while 22 patients were in the neonatal period. Conclusion Calretinin immunostaining is a useful modality in diagnosing suspicious cases of HD. Its results are easy to interpret by less experienced pathologist with accuracy.

Catalytic pyrolysis of ulva lactuca macroalgae: Effects of mono and bimetallic catalysts and reaction parameters on bio-oil up-gradation.

Catalytic pyrolysis of ulva lactuca (UL) macroalgae was studied over a series of ZrO2 supported metal such as Co, Ni and Co-Ni metal catalysts at temperature range of 300-500 °C. Highest bio-oil yield (47.8 wt%) was found with Co-Ni/ZrO2 (10 wt%) catalyst while non-catalytic yielded 42.5 wt% bio-oil. Moreover with increases the metal amount to 15 wt%, the bio-oil yield slightly increased (49.2 wt%). The bio-oil quality significantly improved with using the catalysts compared to the non-catalytic pyrolysis. Catalytic pyrolysis also revealed that introducing Co-Ni into the ZrO2 could result in higher surface area and which increased active sites. Catalytic bio-oils were consisted of mainly long chain hydrocarbon in the range of C6-C16. Moreover, the catalytic bio-oils were showed the higher 'high heating value' (HHV) 38.1 MJ/kg as compare to non-catalytic bio-oils (29.4 MJ/kg). Catalysts have been showed excellent recyclability on bio-oil yield and compounds selectivity.

Beard and Moustache Reconstruction.

Beard and moustache reconstruction has gained more popularity and acceptance over the last decade. The procedure is done for the correction of facial areas with hair density deficit and also for the cosmetic enhancement of pre-existing facial hair. The surgical technique includes the harvesting of grafts from the scalp by the follicular unit excision (FUE) or follicular unit transplantation (FUT) technique and then placing them in either premade slits or by stick and place method. The advancement and refinement of procedure over the years has aided in achieving the optimal aesthetic results, with minimal side effects.

Explication on tissue nutrition in prenatal and postnatal life: An Ayurveda perspective.

Tissue nutrition is the continuous process which is established just after the conception and persists throughout the life. Ayurveda scholars have mentioned that the manner of tissue nutrition is not same in all phases of life. In prenatal life embryo gets nutrition by Upasneha (filtration) and Upasweda (percolation/secretion) and fetus by Garbhanabhinadi (umbilical cord) which is attached with the heart of mother via Rasavahanadi (blood vessels). Thus in intrauterine life the nutrition of embryo is histotrophic, whereas just after the formation of placenta nutrition becomes haemotrophic. In post-natal life nutrition is enteral means nutrients are taken in the form of food via mouth called Aahar. Ayurveda scholars have postulated theories to understand the mechanism of tissue nutrition are Ksheera Dadhi Nyaya (transformation of nutrients), Khale Kapota Nyaya (selective uptake of nutrients), KedariKulya Nyaya (transportation of nutrients via channels), Ek Kala Dhatu Poshan Nyaya (simultaneous supply of nutrients to whole body). The theories of tissue nutrition discussed in Ayurveda suggest that although tissues are nourished and replenished continuously at different rate as per the functional state of Agni by circulating nutrients obtained from Ahara, but tissues are also dependent on each other for their proper nourishment and metabolism. This concept has great implication in management of malnourishment and various other disorders. This manuscript is an attempt to explore the Ayurveda's view on tissue nutrition along with physiological and clinical significance of theories of tissue nutrition in a scientific manner.

Experience on Safety, Expulsion, and Complication of Intracesarean Post-Partum Intrauterine Copper Device.

Background The post-partum period is one of the critical times when ovulation is highly unpredictable and couples often underestimate the likelihood of pregnancy. According to the World Health Organization, intrauterine copper device (IUCD) can be inserted within 48 hours post-partum, referred to as post-partum IUCD (PPIUCD). The objectives of the present study were to determine the safety and expulsion of intracesarean PPIUCD. This study also has an objective to determine the complications (undescended/missed thread, bleeding, pain, and infection) following intracesarean PPIUCD insertion among the women. Materials and methods This was a prospective interventional hospital-based study conducted in the Department of Obstetrics & Gynecology, Uttar Pradesh University of Medical Sciences, Saifai, Etawah, Uttar Pradesh, India, from November 1, 2016, to October 31, 2019. Women were followed up at six weeks and six months for various objectives. Results Intracesarean PPIUCD was inserted in a total of 1,586 patients, and 1,029 cases came for follow-up at six weeks and six months; thus, the concluded sample size was 1,029. The majority of patients were of 20 to 25 years of age, belonged to rural areas, and were having parity 2. The most common complaint was of undescended/missed thread in 22.2% women followed by bleeding (11.9%), expulsion (2.2%), pain (2%), and local infection (1.3%) at six weeks follow-up. At six months, the most common complaint was missed thread in 8.6% followed by bleeding (6.0%), pain (1.6%), expulsion (1.2%), and local infection (0.7%). There was no case of perforation. While 19.05% women wanted the removal of PPIUCD, but at the end of the study period, it was removed in a total of 11.27% cases due to various reasons. Conclusions PPIUCD is an effective tool to reduce the unmet need of contraception. This study showed that most of the women were satisfied with the intracesarean insertion of IUCD, indicating its important place within the basket of post-partum family planning methods.

"Near-Miss" Obstetric Events and Maternal Deaths in a Rural Tertiary Care Center in North India.

Introduction Maternal near-miss and maternal mortality cases have common characters, especially in terms of risk factors. Both of them are indicators of the quality of health care services provided to pregnant women. Our center is a tertiary care center in a rural area of western Uttar Pradesh (U.P.) so we get a large number of referred cases from most of the rural areas of western U.P. and the adjoining areas of other states too, which sometimes end up in mortality. Thus this study was planned to find out the incidence of maternal near-miss events and compare the nature of near-miss events with maternal mortality. Goal and objectives The main objectives of the study were to determine the frequency of maternal near-miss events, observe the trend of near-miss events, and compare the nature of near-miss events with maternal mortality. Materials and methods It was a retrospective study conducted in the department of obstetrics and gynecology at Uttar Pradesh University of Medical Sciences (UPUMS), Saifai, Etawah, from July 2018 - June 2019, over a period of one year. Potentially life-threatening conditions and maternal mortalities were noted from the records of the hospital after taking ethical clearance from the institute. Near-miss cases were noted based on the Health and Family Welfare Government of India guidelines 2014. Data were collected and statistical analysis was performed using the Statistical Package of the Social Sciences (SPSS) version 21 (IBM Corp., Armonk, NY). Results The maternal near-miss incidence ratio was 16.6/1000 live births, the maternal near-miss to mortality ratio was 1.9:1, and the mortality index was 0.34%. Hypertensive disorders of pregnancy were the most common causes of near-miss events (45.8%) followed by hemorrhage (23.6%) in this study. Conclusions Hypertensive disorders in pregnancy and hemorrhage were the two leading causes of near-miss events and mortality followed by sepsis. As the near-miss analysis indicates, the quality of health care and causes are almost similar to maternal mortality, so its registry should be done along with maternal mortality.

Bioactive non-sterol triterpenoid from Streblus asper: microwave-assisted extraction, HPTLC profiling, computational studies and neuro-pharmacological evaluation in BALB/c mice.

CONTEXT: In folk medicine, the stem bark of Streblus asper Lour. (Moraceae) has been reported to possess anticonvulsant activity. However, no systematic/scientific validation is available. Objective This study explores the constituents in the stem bark, their biosassy-guided isolation and their efficacy in neuro-pharmacological disorders, for validating the traditional claims. MATERIALS AND METHODS: Microwave-assisted extraction (MAE) technique was employed to obtain the crude extract. The n-hexane, dichloromethane and aqueous fractions were prepared and phytoconstituents were ascertained by phytochemical tests. The isolated compound, betulin, was characterized by different physicochemical and spectral methods, including HPTLC. Finally, neuro-pharmacological evaluations were conducted at 100, 200, 400 mg/kg b.w., p.o. (25, 50, 100 mg/kg b.w. for betulin) doses in BALB/c mice. RESULTS: The n-hexane fraction (400 mg/kg), and isolated compound betulin (100 mg/kg), showed maximum anticonvulsant activity in maximal electroshock (87.84% and 85.14% seizure inhibition), and isoniazid induced convulsion models (88.85% and 83.18% seizure inhibition), respectively. A dose-dependent attenuation of epileptic seizures was observed, probably through GABArgic mechanism of anticonvulsant action. Moreover, the antidepressant study was also conducted using behavioural models and the results expound that n-hexane and dichloromethane fractions (400 mg/kg) significantly reduced the duration of immobility, as compared to the control. DISCUSSION AND CONCLUSION: This study reports some novel aspects like applying an environmentally benign/green approach of MAE, neuro-pharmacological screening and use of docking studies, for the first time, on the plant S. asper. The findings present a rational explanation for its use in traditional medicine, for the management of neuro-pharmacological disorders.

A rare case of primary tuberculous osteomyelitis of skull vault.

In recent years, there has been a substantial increase in number of reports involving uncommon sites involving in tuberculosis. Rise in number of HIV positive patients has made the scenario worse. Calvarial tuberculosis has beenreported very rarely in world literature till now. We are reporting a case of primary tuberculous osteomyelitis of frontal bone in a 15-year-old female. With prompt as well as careful diagnostic workup and treatment, we were able to halt the disease progression and excellent response to treatment was observed in follow up.

Gap junctions.

Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease.

Design and characterization of the first peptidomimetic molecule that prevents acidification-induced closure of cardiac gap junctions.

BACKGROUND: Gap junctions are potential targets for pharmacologic intervention. We previously developed a series of peptide sequences that prevent closure of connexin43 (Cx43) channels, bind to cardiac Cx43, and prevent acidification-induced uncoupling of cardiac gap junctions. OBJECTIVE: The purpose of this study was to identify and validate the minimum core active structure in peptides containing an RR-N/Q-Y motif. Based on that information, we sought to generate a peptidomimetic molecule that acts on the chemical regulation of Cx43 channels. METHODS: Experiments were based on a combination of biochemical, spectroscopic, and electrophysiologic techniques as well as molecular modeling of active pharmacophores with Cx43 activity. RESULTS: Molecular modeling analysis indicated that the functional elements of the side chains in the motif RRXY form a triangular structure. Experimental data revealed that compounds containing such a structure bind to Cx43 and prevent Cx43 chemical gating. These results provided us with the first platform for drug design targeted to the carboxyl terminal of Cx43. Using that platform, we designed and validated a peptidomimetic compound (ZP2519; molecular weight 619 Da) that prevented octanol-induced uncoupling of Cx43 channels and pH gating of cardiac gap junctions. CONCLUSION: Structure-based drug design can be applied to the development of pharmacophores that act directly on Cx43. Small molecules containing these pharmacophores can serve as tools to determine the role of gap junction regulation in the control of cardiac rhythm. Future studies will determine whether these compounds can function as pharmacologic agents for the treatment of a selected subset of cardiac arrhythmias.

Gap junction protein Cx37 interacts with endothelial nitric oxide synthase in endothelial cells.

OBJECTIVE: The gap junction protein connexin37 (Cx37) plays an important role in cell-cell communication in the vasculature. A C1019T Cx37 gene polymorphism, encoding a P319S substitution in the regulatory C terminus of Cx37 (Cx37CT), correlates with arterial stenosis and myocardial infarction in humans. This study was designed to identify potential binding partners for Cx37CT and to determine whether the polymorphism modified this interaction. METHODS AND RESULTS: Using a high-throughput phage display, we retrieved 2 binding motifs for Cx37CT: WHK ... [K,R]XP ... and FHK ... [K,R]XXP ... , the first being more common for Cx37CT-319P and the second more common for Cx37CT-319S. One of the peptides (WHRTPRLPPPVP) showed 77.7% homology with residues 843 to 854 of endothelial nitric oxide synthase (eNOS). In vitro binding of this peptide or of the homologous eNOS sequence to both Cx37CT isoforms was confirmed by cross-linking and surface plasmon resonance. Electrophysiological analysis of Cx37 single channel activity in transfected N2a cells showed that eNOS-like and eNOS(843-854) increased the frequency of events with conductances higher than 300 pS. We demonstrated that eNOS coimmunoprecipitated with Cx37 in a mouse endothelial cell (EC) line (bEnd.3), human primary ECs, and a human EC line transfected with Cx37-319P or Cx37-319S. Cx37 and eNOS colocalized at EC membranes. Moreover, a dose-dependent increase in nitric oxide production was observed in ECs treated with Cx37 antisense. CONCLUSIONS: Overall, our data show for the first time a functional and specific interaction between eNOS and Cx37. This interaction may be relevant for the control of vascular physiology both in health and in disease.

Novel pharmacophores of connexin43 based on the "RXP" series of Cx43-binding peptides.

Gap junction pharmacology is a nascent field. Previous studies have identified molecules that enhance intercellular communication, and may offer potential for innovative antiarrhythmic therapy. However, their specific molecular target(s) and mechanism(s) of action remain unknown. Previously, we identified a 34-aa peptide (RXP-E) that binds the carboxyl terminal domain of Cx43 (Cx43CT) and prevents cardiac gap junction closure and action potential propagation block. These results supported the feasibility of a peptide-based pharmacology to Cx43, but the structure of the core active element in RXP-E, an essential step for pharmacological development, remained undefined. Here, we used a combination of molecular modeling, surface plasmon resonance, nuclear magnetic resonance and patch-clamp strategies to define, for the first time, a unique ensemble of pharmacophores that bind Cx43CT and prevent closure of Cx43 channels. Two particular molecules are best representatives of this family: a cyclized heptapeptide (called CyRP-71) and a linear octapeptide of sequence RRNYRRNY. These 2 small compounds offer the first structural platform for the design of Cx43-interacting gap junction openers. Moreover, the structure of these compounds offers an imprint of a region of Cx43CT that is fundamental to gap junction channel function.