The Role of Artificial Intelligence in Improving Patient Outcomes and Future of Healthcare Delivery in Cardiology: A Narrative Review of the Literature

Cardiovascular diseases exert a significant burden on the healthcare system worldwide. This narrative literature review discusses the role of artificial intelligence (AI) in the field of cardiology. AI has the potential to assist healthcare professionals in several ways, such as diagnosing pathologies, guiding treatments, and monitoring patients, which can lead to improved patient outcomes and a more efficient healthcare system. Moreover, clinical decision support systems in cardiology have improved significantly over the past decade. The addition of AI to these clinical decision support systems can improve patient outcomes by processing large amounts of data, identifying subtle associations, and providing a timely, evidence-based recommendation to healthcare professionals. Lastly, the application of AI allows for personalized care by utilizing predictive models and generating patient-specific treatment plans. However, there are several challenges associated with the use of AI in healthcare. The application of AI in healthcare comes with significant cost and ethical considerations. Despite these challenges, AI will be an integral part of healthcare delivery in the near future, leading to personalized patient care, improved physician efficiency, and anticipated better outcomes.

A Case of Non-cirrhotic Portal Hypertension With Antiphospholipid Syndrome

Nodular regenerative hyperplasia (NRH) and obliterative portal venopathy (OPV) are two causes of non-cirrhotic portal hypertension (NCPH), which is a vascular liver disease wherein clinical signs of portal hypertension (PHT), such as esophageal varices, ascites, and splenomegaly develop in the absence of cirrhosis and portal vein thrombosis. The etiology often remains unidentified, but herein we present the case of a 56-year-old male with NCPH and refractory ascites who underwent liver biopsy confirming NRH and OPV. Etiological workup revealed beta-2 glycoprotein-1 and anticardiolipin antibodies, concerning antiphospholipid syndrome (APS) despite no prior history of thrombosis. The patient underwent a transjugular intrahepatic portosystemic shunt (TIPS) procedure for his refractory ascites and was started on prophylactic anticoagulation owing to a concern for APS with clinical improvement in his ascites and shortness of breath. Pursuing TIPS earlier in the setting of refractory ascites, as well as offering anticoagulation therapy for patients with possible APS to prevent the development of potential thromboses, could be appropriate recommendations to prevent complications in the disease course. This case report highlights the need for further investigations on the etiologies, diagnosis pathways, and treatment options for NCPH.

Personalized Approach to Chronic Antibiotic-Refractory Pouchitis: A Case Report and Review of the Literature

Patients who undergo restorative proctocolectomy and ileoanal anastomosis can develop pouchitis as a common chronic complication. A rare subset of patients fails to respond to multiple antibiotic therapies and develop chronic antibiotic-refractory pouchitis (CARP). We present a case of a 45-year-old male with pouchitis refractory to chronic antibiotic therapy and histology demonstrating chronic inflammatory changes. Management involved mesalamine and probiotics, resulting in a positive clinical response and symptom absence on follow-up. This case highlights the intricacies of treating chronic pouchitis post ileoanal anastomosis, showcasing the efficacy of a personalized approach using mesalamine and probiotics. CARP is emerging as an entity associated with poor quality of life and increased healthcare costs. CARP fails to respond to multiple courses of antibiotic therapy. Therefore, the management of CARP is difficult and limited. Current literature on the management of CARP is scarce and mainly involves immunomodulatory therapy and probiotics. It is essential to keep this differential diagnosis in mind in patients with recurrent pouchitis episodes and start them on immunomodulator treatment and probiotics rather than repeated courses of antibiotics.

The Role of the Intestinal Microbiome in Multiple Sclerosis-Lessons to Be Learned from Hippocrates

Based on recent advances in research of chronic inflammatory conditions, there is a growing body of evidence that suggests a close correlation between the microbiota of the gastrointestinal tract and the physiologic activity of the immune system. This raises the idea that disturbances of the GI ecosystem contribute to the unfolding of chronic diseases including neurodegenerative pathologies. Here, we overview our current understanding on the putative interaction between the gut microbiota and the immune system from the aspect of multiple sclerosis, one of the autoimmune conditions accompanied by severe chronic neuroinflammation that affects millions of people worldwide.

The Utility of Artificial Intelligence in the Diagnosis and Management of Pancreatic Cancer

Artificial intelligence (AI) has made significant advancements in the medical domain in recent years. AI, an expansive field comprising Machine Learning (ML) and, within it, Deep Learning (DL), seeks to emulate the intricate operations of the human brain. It examines vast amounts of data and plays a crucial role in decision-making, overcoming limitations related to human evaluation. DL utilizes complex algorithms to analyze data. ML and DL are subsets of AI that utilize hard statistical techniques that help machines consistently improve at tasks with experience. Pancreatic cancer is more common in developed countries and is one of the leading causes of cancer-related mortality worldwide. Managing pancreatic cancer remains a challenge despite significant advancements in diagnosis and treatment. AI has secured an almost ubiquitous presence in the field of oncological workup and management, especially in gastroenterology malignancies. AI is particularly useful for various investigations of pancreatic carcinoma because it has specific radiological features that enable diagnostic procedures without the requirement of a histological study. However, interpreting and evaluating resulting images is not always simple since images vary as the disease progresses. Secondly, a number of factors may impact prognosis and response to the treatment process. Currently, AI models have been created for diagnosing, grading, staging, and predicting prognosis and treatment response. This review presents the most up-to-date knowledge on the use of AI in the diagnosis and treatment of pancreatic carcinoma.

Autoimmune Hypoglycemia With Anti-Insulin Autoantibodies in an Eighty-One-Year-Old Woman Without Apparent Risk Factors

Background/Objective

Insulin autoimmune syndrome (IAS) is a very rare cause of hypoglycemia presenting with recurrent fasting or postprandial hypoglycemia episodes with elevated serum insulin levels and insulin autoantibodies. The objective of this case is to highlight the importance of considering IAS in patients with hypoglycemia.

Case Report

We present a case of an 81-year-old female who presented with symptoms of hypoglycemia. She was found to have hyperinsulinemic hypoglycemic episodes without any apparent risk factors for IAS. She had positive-insulin autoantibodies in her serum leading to the diagnosis of IAS. Acutely, hypoglycemia was managed with D50 pushes, oral glucose, and glucagon injection.

Discussion

Patients who present with hypoglycemia due to endogenous hyperinsulinemia should have IAS considered as a possible differential diagnosis. Insulin autoantibodies are measured as the gold standard diagnostic test for IAS. Foods with a low glycemic index are the primary treatment for IAS.

Conclusion

This case presentation highlights the importance of considering IAS as a differential diagnosis in patients presenting with hypoglycemia secondary to hyperinsulinemia, even in the absence of apparent risk factors.

The Utility of Language Models in Cardiology: A Narrative Review of the Benefits and Concerns of ChatGPT-4

Artificial intelligence (AI) and language models such as ChatGPT-4 (Generative Pretrained Transformer) have made tremendous advances recently and are rapidly transforming the landscape of medicine. Cardiology is among many of the specialties that utilize AI with the intention of improving patient care. Generative AI, with the use of its advanced machine learning algorithms, has the potential to diagnose heart disease and recommend management options suitable for the patient. This may lead to improved patient outcomes not only by recommending the best treatment plan but also by increasing physician efficiency. Language models could assist physicians with administrative tasks, allowing them to spend more time on patient care. However, there are several concerns with the use of AI and language models in the field of medicine. These technologies may not be the most up-to-date with the latest research and could provide outdated information, which may lead to an adverse event. Secondly, AI tools can be expensive, leading to increased healthcare costs and reduced accessibility to the general population. There is also concern about the loss of the human touch and empathy as AI becomes more mainstream. Healthcare professionals would need to be adequately trained to utilize these tools. While AI and language models have many beneficial traits, all healthcare providers need to be involved and aware of generative AI so as to assure its optimal use and mitigate any potential risks and challenges associated with its implementation. In this review, we discuss the various uses of language models in the field of cardiology.

Ocular and orbital manifestations of granulomatosis with polyangiitis: a systematic review of published cases

Objective: Granulomatosis with polyangiitis (GPA) is an autoimmune disorder characterized by necrotizing granulomatous inflammation of small and medium-sized vessels. This systematic review aimed to highlight the most common ophthalmic manifestations and to uncover their associations with antineutrophil cytoplasmic antibody (ANCA) positivity and the presence of granulomas. Methods: A literature search of PubMed, Web of Science, and Scopus electronic databases was performed from journal inception to March 21, 2021, for case reports and a series of ophthalmic GPAs. Cytoplasmic-ANCA (c-ANCA), perinuclear-ANCA (p-ANCA), and granulomas were analyzed against many ophthalmic signs and symptoms. 306 patients with GPA were retrospectively studied. Results: Granulomas were present in 47.7% of our sample, c-ANCA in 59.2%, and p-ANCA in 10.8%. Scleritis was significantly associated with higher odds for c-ANCA positivity. Eye discharge, episcleritis, proptosis, and central nervous system (CNS) involvement were each significantly associated with lower odds for c-ANCA positivity. Orbital mass was significantly associated with lower odds for p-ANCA positivity. CNS involvement was significantly associated with higher odds for p-ANCA positivity (OR:3.08, 95% CI:1.02, 9.36, p=0.047) and orbital mass was significantly associated with lower odds for p-ANCA positivity. Conclusions: We recommend that clinicians should consider ocular or orbital GPA in patients presenting with non-specific eye complaints, such as vision impairment, orbital mass, or proptosis, and obtain further assessments to determine the possible presence of granuloma, c-ANCA, or p-ANCA. Abbreviations: GPA = Granulomatosis with Polyangiitis, ANCA = antineutrophil cytoplasmic antibody, c-ANCA = cytoplasmic-ANCA, p-ANCA = perinuclear-ANCA, CNS = central nervous system, AAVs = ANCA-associated vasculitides, SD = standard deviation, GU = genitourinary, ENT = ear nose and throat, OR = odds ratio, CI = confidence interval.

Outcomes of Acute Mesenteric Ischemia in End-Stage Renal Disease and Predictors of Mortality: A Nationwide Assessment

Background Acute mesenteric ischemia (AMI) is an uncommon disease caused by obstruction of blood flow to the bowel, which can lead to high mortality rates. End-stage renal disease (ESRD) is another disease commonly seen in the elderly. There are limited data evaluating the relationship between AMI and ESRD, but it has been shown that ESRD patients have a higher risk of mesenteric ischemia than the general population. Methods This retrospective analysis utilized the National Inpatient Sample database for 2016, 2017, and 2018 to identify patients with AMI. Patients were then divided into two groups, AMI with ESRD and AMI only. All-cause in-patient mortality, hospital length of stay (LOS), and total costs were identified. The Student's t-test was used to analyze continuous variables, while Pearson's Chi-square test was used to analyze categorical variables. Results A total of 169,245 patients were identified, with 10,493 (6.2%) having ESRD. The AMI with ESRD group had a significantly higher mortality rate than the AMI-only group (8.5% vs 4.5%). Patients with ESRD had a longer LOS (7.4 days vs 5.3 days; P = 0.00), and higher total hospital cost ($91,520 vs $58,175; P = 0.00) compared to patients without ESRD. Conclusion The study found that patients with ESRD who were diagnosed with AMI had a significantly higher mortality rate, longer hospital stays, and higher hospital costs than patients without ESRD.

Outcomes of Portal Vein Thrombosis in Smokers With and Without Cirrhosis and Predictors of Mortality: A Nationwide Assessment

Portal vein thrombosis (PVT) is a rare condition that can lead to numerous complications, like variceal bleeding, hepatic encephalopathy, and chronic liver disease. PVT has various etiologies, including liver disease, infections, and hyper-coagulable disorders. Cirrhosis, a chronic progressive liver condition characterized by liver fibrosis, is one of the risk factors for the development of PVT. Secondly, smoking also increases the risk of PVT. The aim of this study is to identify outcomes in patients with PVT who smoked with and without cirrhosis. This study was performed using the National Inpatient Sample (NIS) database for the years 2016, 2017, and 2018. The study identified 33,314 patients diagnosed with PVT who smoked, of which 14,991 had cirrhosis, and 18,323 did not have cirrhosis. Patients with PVT and cirrhosis had significantly higher in-hospital mortality, upper gastrointestinal bleeds, acute kidney injury, and peritonitis compared to patients without cirrhosis. The results of the study show that patients with PVT and cirrhosis who smoke have a higher risk of unfavorable outcomes.

Pancreatic Heterotopia at the Gastroesophageal Junction: A Case Report and Review of the Literature

Pancreatic heterotopia is characterized by the presence of pancreatic tissue in a location outside of its typical anatomical position. Symptoms of pancreatic heterotopia vary based on the location of the ectopic tissue. It is commonly asymptomatic and often diagnosed incidentally during routine endoscopy. Clinically significant pancreatic heterotopia is often secondary to inflammation, bleeding, obstruction, and malignant transformation. The most common location of heterotopic pancreas is within 5 cm of the pylorus usually on the greater curvature. Involvement of the gastroesophageal junction is extremely rare. In this report, we describe the case of a 57-year-old woman who was diagnosed with ectopic pancreatic tissue at the gastroesophageal junction by esophagogastroduodenoscopy after presenting with symptoms of dyspepsia.

Hepatic Dystrophic Calcification Secondary to Transarterial Chemoembolization: Case Report and Review of Literature

Hepatocellular carcinoma (HCC) is a common malignancy usually treated with surgery. Patients who are not suitable for surgery undergo transarterial chemoembolization (TACE) which involves injecting anti-cancer drugs and embolizing agents into the hepatic artery. Although it is a relatively safe procedure with minor side effects, TACE can rarely cause dystrophic calcification in the liver. We report a case of a 58-year-old female who presented with right-sided chest pain. The patient had been previously treated for HCC with a TACE procedure. A chest x-ray revealed hepatic calcification which was likely secondary to the prior TACE. This case study emphasizes the significance of considering TACE as a potential cause of hepatic dystrophic calcification.

Non-islet cell tumor hypoglycemia associated with Gastrointestinal Stromal Tumor: Case report and review of the literature

Non-islet cell tumor hypoglycemia is an uncommon paraneoplastic phenomenon commonly associated with tumors of mesenchymal origin like gastrointestinal stromal tumors (GIST). It causes the release of insulin-like growth factor type II. GIST are frequently asymptomatic but can present with vague symptoms such as gastrointestinal bleeding, gastric pain, anorexia, nausea, and vomiting. We present an interesting case of A 62-year-old male with GIST tumor admitted for refractory hypoglycemia found to have non-islet cell tumor hypoglycemia which is a relatively uncommon cause of hypoglycemia.

Gut-brain axis: Review on the association between Parkinson's disease and plant lectins

Gastrointestinal (GI) involvement in the pathogenesis of Parkinson's Disease (PD) has been widely recognized and supported in recent literature. Prospective and retrospective studies found non-motor symptoms within the GI, specifically constipation, precede cardinal signs and cognitive decline by almost 20 years. In 2002, Braak et al. were the first to propose that PD is a six-stage propagating neuropathological process originating from the GI tract (GIT). Aggregated α-synuclein (α-syn) protein from the GIT is pathognomonic for the development of PD. This article reviews the current literature from the past 10 years as well as original research found in PubMed on the combined effects of enteric glial cells and lectins on the development of Parkinson's Disease. Studies have found that these aggregated and phosphorylated proteins gain access to the brain via retrograde transport through fast and slow fibers of intestinal neurons. Plant lectins, commonly found within plant-based diets, have been found to induce Leaky Gut Syndrome and can activate enteric glial cells, causing the release of pro-inflammatory cytokines. Oxidative stress on the enteric neurons, caused by a chronic neuro-inflammatory state, can cause a-syn aggregation and lead to Lewy Body formation, a hallmark finding in PD. Although the current literature provides a connection between the consumption of plant lectins and the pathophysiology of PD, further research is required to evaluate confounding variables such as food antigen mimicry and other harmful substances found in our diets.

Thromboembolic Events in Patients with Inflammatory Bowel Disease: A Comprehensive Overview

Inflammatory bowel disease (IBD), Crohn’s disease and ulcerative colitis are chronic inflammatory disorders of the intestines. The underlying inflammation activates the coagulation cascade leading to an increased risk of developing arterial and venous thromboembolic events such as deep vein thrombosis and pulmonary embolism. Patients with IBD are at a 2–3-fold increased risk of developing thromboembolism. This risk increases in patients with active IBD disease, flare-ups, surgery, steroid treatment, and hospitalization. These complications are associated with significant morbidity and mortality making them important in clinical practice. Clinicians should consider the increased risk of thromboembolic events in patients with IBD and manage them with appropriate prophylaxis based on the risk. In this review, we discuss the literature associated with the pathophysiology of thromboembolism in patients with IBD, summarize the studies describing the various thromboembolic events, and the management of thromboembolism in patients with IBD.

Is checklist an effective tool for teaching research students? A survey-based study

BACKGROUND

Students face hardships in determining what are the main points that need more studying in every subject. Checklists are one of the ways that can help students identify the most important pieces of information. Accordingly, in this study, we aimed at examining the impact of using educational checklists on the learning process of postgraduate students at Nagasaki University, Japan.

METHODS

Thirty-one Master's students, who finished a "how to write a research protocol" course were recruited by sending them an invitation email that had an attached link to a previously developed and tested questionnaire on the SurveyMonkey® platform. After signing the electronic informed consent, twenty-two participants (response rate = 71%) finished the survey. The data was analyzed using Microsoft Excel and expressed in the form of frequencies and percentages.

RESULTS

More than half of the students declared that they know the checklist will be used in the course that we investigated. Only two students used checklists as a means of studying (9%). Twelve students (55%) confirmed that no other courses or lessons in the School of Tropical Medicine and Global Health (TMGH) use checklists. No students found the usage of checklists not easy or not practical to apply. Many students thought the length of the checklist was suitable and not too short (64%), although three students (14%) found it lengthy. Moreover, most students described the checklist as beyond good (86%) and they would recommend using a checklist for teaching other college students (73%).

CONCLUSION

Using checklists in education can facilitate the learning process, help in memorization, and deepen the concepts being studied. Further studies are required to examine the impact of checklists in teaching undergraduate students and students from other non-healthcare disciplines.

An Unusual Case of Drug-Induced Liver Injury Secondary to Nitrofurantoin Use

Nitrofurantoin is a commonly prescribed antibiotic for uncomplicated urinary tract infections. Despite a number of side effects, it is increasingly prescribed due to its low cost, high efficacy, and minimal antimicrobial resistance. One of the rare, however significant side effects of nitrofurantoin is idiosyncratic drug-induced liver toxicity. It commonly presents with abdominal pain and elevated liver enzymes. Interestingly, it can cause either an acute or a chronic hepatitis-like syndrome that can be severe and lead to liver failure or cirrhosis. We present a case of a healthy 24-year-old female who presented with epigastric abdominal pain, which was found to be drug-induced liver injury (DILI) secondary to her recent nitrofurantoin use.

Factors impacting COVID-19 vaccination intention among medical students

Medical students represent a significant part of the health-care community and are active members of the coronavirus disease 2019 (COVID-19) response. This study aimed to evaluate various factors associated with COVID-19 vaccine intention among medical students via an online anonymous survey. A total of 370 students completed the online survey, with 229 (61.89%) not vaccinated for COVID-19. Of students not yet vaccinated, 45 (19.65%) were unsure or did not intend to accept the vaccine, while 184 (80.35%) intend to be vaccinated within 6 months. Overall, female gender, health status, clinical science enrollment, and the practice of COVID-19 preventative behaviors significantly correlated with the intention to be vaccinated within 6 months. Greater perceived risk for contracting COVID-19, lesser beliefs that the COVID-19 vaccination trials were rushed, and greater beliefs that being vaccinated would help complete their medical education were uniquely associated with the intention to be vaccinated within 6 months. Collectively, this study identified several factors that influenced medical students' intention to receive the COVID-19 vaccination. This information may be used in future immunization strategies to increase the vaccination rates among this group of future medical professionals.

Stem Cell Therapy for Post-Traumatic Stress Disorder: A Novel Therapeutic Approach

Stem cell therapy is a rapidly evolving field of regenerative medicine being employed for the management of various central nervous system disorders. The ability to self-renew, differentiate into specialized cells, and integrate into neuronal networks has positioned stem cells as an ideal mechanism for the treatment of epilepsy. Epilepsy is characterized by repetitive seizures caused by imbalance in the GABA and glutamate neurotransmission following neuronal damage. Stem cells provide benefit by reducing the glutamate excitotoxicity and strengthening the GABAergic inter-neuron connections. Similar to the abnormal neuroanatomic location in epilepsy, post-traumatic stress disorder (PTSD) is caused by hyperarousal in the amygdala and decreased activity of the hippocampus and medial prefrontal cortex. Thus, stem cells could be used to modulate neuronal interconnectivity. In this review, we provide a rationale for the use of stem cell therapy in the treatment of PTSD.

Extracellular Vehicles of Oxygen-Depleted Mesenchymal Stromal Cells: Route to Off-Shelf Cellular Therapeutics?

Cellular therapy is a promising tool of human medicine to successfully treat complex and challenging pathologies such as cardiovascular diseases or chronic inflammatory conditions. Bone marrow-derived mesenchymal stromal cells (BMSCs) are in the limelight of these efforts, initially, trying to exploit their natural properties by direct transplantation. Extensive research on the therapeutic use of BMSCs shed light on a number of key aspects of BMSC physiology including the importance of oxygen in the control of BMSC phenotype. These efforts also led to a growing number of evidence indicating that the beneficial therapeutic effects of BMSCs can be mediated by BMSC-secreted agents. Further investigations revealed that BMSC-excreted extracellular vesicles could mediate the potentially therapeutic effects of BMSCs. Here, we review our current understanding of the relationship between low oxygen conditions and the effects of BMSC-secreted extracellular vesicles focusing on the possible medical relevance of this interplay.

Clinical trial of benidipine in mild to moderate hypertension

Thirty four patients with mild to moderate hypertension, were put on benidipine 4 mg/day after two weeks of placebo therapy. Twenty five patients completed the trial successfully for 4 mg benidipine. The blood pressure of 20 patients was controlled with benidipine 4 mg/day (effective rate 80%). Five patients with unsatisfactory control on 4 mg/day benidipine were put on 8 mg/day. Four of them were controlled and one was considered as failure (effective rate 80%). Most of the patients tolerated the drug well. Three patients had mild side effects like headache and heaviness in the head. One of them also had puffiness of face and body (on benidipine 8 mg/day) and was withdrawn from the study. One patient had mild constipation. We conclude that benidipine is well tolerated in the dose of 4-8 mg/day and is an effective antihypertensive agent for treatment of patients with mild to moderate hypertension.

Decomposition of alpha-hydroxyaryl ketones and characterization of some unusual products

Alpha-Hydroxyaryl ketones such as 2-hydroxypropiophenone and 1-(2,4-difluorophenyl)-2-hydroxy-1-propanone, the key intermediates in the preparation of antifungal agents, decompose into oxidized, rearranged, and condensed products. These products were isolated and characterized. The possible mechanisms for the formation of the products are discussed.

Effects of the affinity ligands 14-beta-chloroacetylnaltrexone and 14-beta-bromoacetamidomorphine on [3H]-dihydromorphine binding sites in rat brain

The aim of the present study was to examine the inhibitory effects in vitro of the affinity ligands 14-beta-chloroacetylnaltrexone (CAN) and 14-beta-bromoacetamidomorphine (BAM) to characterize the pharmacological specificity of the ligands for high and low affinity opioid binding sites. Rat brain membranes were incubated with 2.0 microM BAM or CAN, or their parent compounds (morphine and naltrexone, respectively) at 37 degrees for 45 min, and the membranes were washed extensively to remove the unbound ligand. The specific binding of 0.3 nM [3H]dihydromorphine ([3H]DHM) was reduced 32 +/- 7% in membranes treated with CAN and BAM, whereas specific binding in preparations treated with morphine and naltrexone was not significantly different from controls. An increased affinity of BAM and CAN relative to morphine and naltrexone could not account for the observed irreversible inhibition, since the relative affinity of CAN was similar to that of naltrexone and that of BAM was 10-fold less active than morphine. Saturation binding assays revealed that the affinity ligands selectively abolished a high affinity binding site (Kd = 0.3 nM, Bmax 95 fmoles/mg protein), which comprised approximately one-third of the total number of sites. The affinity of the remaining site (Kd = 4.0 nM) was not altered significantly. The results indicate that the inhibition caused by the affinity ligands is irreversible and represents inactivation of high affinity opioid binding sites in a relatively selective manner.

Nicotine-induced membrane perturbation of intact human granulocytes spin-labeled with 5-doxylstearic acid. Correlation with chemotaxis

The effects of nicotine on intact human granulocytes were examined, using 5-doxylstearic acid as a spin probe. At micromolar concentrations, (-)-nitocine produces a membrane perturbation in granulocytes not observable with oriented lipid bilayers. The effect, which is stereoselective for the (-)-isomer, occurs at concentrations of nicotine that bind to noncholinergic nicotine receptors on granulocytes and which are present in the blood after smoking. At comparable concentrations, (-)-nicotine modulates granulocyte chemotaxis towards a chemotactic peptide in a stereospecific and dose-dependent manner. Cotinine, the major metabolite of nicotine, does not bind to the receptor, does not produce the membrane perturbation observed with nicotine, and has no effect on chemotaxis. These results suggest that (-)-nicotine present in the blood after smoking binds to a receptor on granulocytes, perturbs granulocyte membranes and modulates chemotaxis.

Synthesis and properties of some spin labeled long chain aliphatic acids

We have synthesized and characterized a series of spin labeled aliphatic acids with variable chain lengths between the nitroxide radicals and the carboxylic group. These molecules should be of general utility in labeling a variety of substrates which can react with the free carboxylic acid group. Variable temperature esr studies have been conducted with some of these molecules to characterize molecular motion as a function of solvent viscosity.

Affinity labeling and purification of the opiate receptor from rat brain

Affinity labeling of the opiate receptor has been performed on neural membranes from rat brain utilizing[125I]-14-bromoacetamidomorphine, an opiate agonist, and [125I]-14-chloracetylmorphine, an antagonist. With the use of SDS gel electrophoresis it could be shown that the agonist labeled three proteins with molecular weights of 43,000, 35,000 and 23,000, whereas the antagonist only labeled the 23,000 component. The preferential labeling of the 23,000 protein by the antagonist suggests that this component may be a primary recognition site for opiate antagonists. Calcium was stimulatory to the affinity labeling of all three proteins while sodium was inhibitory. With the use of affinity columns prepared by conjugating either ligand to omega-aminohexyl Sepharose, a receptor complex was obtained consisting all three proteins. Stereospecific opiate binding was demonstrable in the complex prepared from either column.