- Home
- A-Z Publications
- Annual Review of Medicine
- Previous Issues
- Volume 49, 1998
Annual Review of Medicine - Volume 49, 1998
Volume 49, 1998
- Review Articles
-
-
-
Chronic Fatigue Syndrome: An Update
Vol. 49 (1998), pp. 1–13More LessAmong the many patients who seek medical care for the complaint of fatigue, a small number suffer from chronic fatigue syndrome (CFS). CFS is a poorly understood condition characterized by debilitating fatigue and associated symptoms lasting at least six months. Studies indicate that the illness is not simply a manifestation of an underlying psychiatric disorder, but rather is an illness characterized by activation of the immune system, various abnormalities of several hypothalamic-pituitary axes, and reactivation of certain infectious agents.
-
-
-
-
The Extracellular Calcium-Sensing Receptor: Its Role in Health and Disease
Vol. 49 (1998), pp. 15–29More LessThe recent cloning of an extracellular calcium (Ca2+o)-sensing receptor (CaR) from parathyroid, kidney and other cell types has clarified the mechanisms through which Ca2+o exerts its direct actions on various cells and tissues. In the parathyroid, the CaR mediates the inhibitory effects of Ca2+o on parathyroid hormone (PTH) secretion and likely on expression of the PTH gene and parathyroid cellular proliferation. In the kidney, the receptor mediates direct inhibition of the reabsorption of divalent cations in the cortical thick ascending limb, and it likely underlies the inhibitory actions of hypercalcemia on the urinary-concentrating mechanism in the medullary thick ascending limb and inner medullary collecting duct. The identification of inherited diseases of Ca2+o-sensing that arise from mutations in the CaR gene has proven, by genetic means, the central role of the CaR in mineral ion homeostasis and the importance of the receptor in regulating the parathyroid and kidney. An allosteric CaR agonist (“calcimimetic”) is currently being tested for the treatment of primary hyperparathyroidism, and CaR-based therapeutics will likely be applicable to other disorders in which CaRs are under- or overactive. Thus the discovery of the CaR and its associated diseases has documented that Ca2+o plays an essential role as an extracellular first messenger, in addition to serving its better recognized role as an intracellular second messenger.
-
-
-
Homocysteine and Cardiovascular Disease
Vol. 49 (1998), pp. 31–62More LessAn elevated level of total homocysteine (tHcy) in blood, denoted hyperhomocysteinemia, is emerging as a prevalent and strong risk factor for atherosclerotic vascular disease in the coronary, cerebral, and peripheral vessels, and for arterial and venous thromboembolism. The basis for these conclusions is data from about 80 clinical and epidemiological studies including more than 10,000 patients. Elevated tHcy confers a graded risk with no threshold, is independent of but may enhance the effect of the conventional risk factors, and seems to be a particularly strong predictor of cardiovascular mortality. Hyperhomocysteinemia is attributed to commonly occurring genetic and acquired factors including deficiencies of folate and vitamin B12. Supplementation with B-vitamins, in particular with folic acid, is an efficient, safe, and inexpensive means to reduce an elevated tHcy level. Studies are now in progress to establish whether such therapy will reduce cardiovascular risk.
-
-
-
The Open-Artery Hypothesis
A. Solomon, and B. GershVol. 49 (1998), pp. 63–76More LessEarly reperfusion of an infarct-related coronary artery results in myocardial salvage, with subsequent improvement in left ventricular function and survival. However, late reperfusion, which occurs at a time when myocardial salvage is no longer possible, still exerts a favorable impact on left ventricular function and survival. This concept is known as the open-artery hypothesis. Possible mechanisms for this benefit include improved infarct healing, limitation of ventricular remodeling, decreased ventricular arrhythmias, and reperfusion of hibernating myocardium. Although an open infarct-related coronary artery is crucial, it has not been proven that opening an occluded coronary artery using angioplasty is beneficial. A large randomized clinical trial is clearly needed.
-
-
-
Pathophysiology of Atrial Flutter
Vol. 49 (1998), pp. 77–83More LessAtrial flutter is a macroreentrant tachyarrhythmia most often contained within the right atrium. Typical atrial flutter is defined on an electrocardiogram by the classic “sawtooth” pattern of flutter waves with negative polarity in leads II, III, and aVF. In contrast to atrial fibrillation, which is sustained by multiple reentrant wavelets defined by anatomic and/or functional barriers, typical atrial flutter is sustained by a single reentrant circuit defined by anatomical barriers. The isthmus of atrial tissue bordered by the inferior vena cava and the tricuspid annulus forms a critical zone of slow conduction in the reentry circuit of atrial flutter. The goal of radiofrequency catheter ablation is to create a line of conduction block across this isthmus. This line of block interrupts the flutter circuit and often provides long-term freedom from recurrence.
-
-
-
New Approaches to Supporting the Failing Liver
Vol. 49 (1998), pp. 85–94More LessWith the continued, growing disparity between the numbers of organ donations and patients waiting for liver transplantation, various efforts have been made to optimize the allocation of organs, as well as to devise means to support the failing liver. Over the years, the development of bioartificial liver-assist devices has aimed at replacing the three main functions of hepatocytes, which are synthetic, metabolic, and excretory. The application of porcine hepatocytes in humans to carry out biotransformation, as well as other metabolic functions and refinement of the membrane separator, have yielded some promising results in supporting patients with acute liver failure. Further advances will need to be made before these bioartificial devices can be considered for routine application in clinical settings.
-
-
-
Assessing Risks, Costs, and Benefits of Laparoscopic Hernia Repair
Vol. 49 (1998), pp. 95–109More LessLaparoscopic inguinal herniorrhaphy (LIHR) was introduced with the following potential advantages: less postoperative discomfort and pain, reduced recovery time that allows earlier return to full activity, easier repair of a recurrent hernia, the ability to treat bilateral hernias concurrently, the performance of a simultaneous diagnostic laparoscopy, ligation of the hernia sac at the highest possible site, improved cosmesis, and decreased incidence of recurrence. Potential disadvantages include complications, such as bowel, bladder, and vascular injuries; potential adhesive complications at sites where the peritoneum has been breached or prosthetic material has been placed; the apparent need, at least at the present, for a general anesthetic; and the increased cost because of expensive equipment needs. Most surgeons agree that LIHR has a role in the management of patients with a recurrent hernia after a conventional inguinal herniorrhaphy (CIHR), bilateral inguinal hernia, or a need for laparoscopy for another procedure, such as laparoscopic cholecystectomy. The routine use of LIHR for the unilateral, uncomplicated hernia is a more contentious issue.
-
-
-
Detection of Minimal Residual Disease: Relevance for Diagnosis and Treatment of Human Malignancies
Vol. 49 (1998), pp. 111–122More LessMinimal residual disease (MRD) is the tumor burden that is present after a course of treatment that has resulted in clinical remission. For hematopoietic malignancies, techniques for detection of this minimal tumor burden are being used to monitor MRD. These involve methods that are capable of identifying very low numbers of neoplastic cells in an otherwise normal marrow or lymph node. Patients with demonstrable residual neoplastic cells tend to do worse than patients without detectable cells; however, results depend on the timing of the assay and whether the detectable neoplastic cells appear to be increasing in number with subsequent assays. For bone marrow transplantation, assays incorporating chimerism analyses, cytogenetics, and morphology are used to regulate therapy.
-
-
-
Chronic Pain
Vol. 49 (1998), pp. 123–133More LessChronic pain is an emotional experience and is defined as pain lasting greater than six months. It is important to understand the neurophysiology of pain in order to treat it. Nociceptors in the periphery travel to the substantia gelatinosa of the spinal cord while secondary and tertiary afferents transmit information from the dorsal horn to the brain. Modification of pain information may take place in these ascending pathways or in descending pathways. Treatment of chronic pain is most successful when it is approached in a multidisciplinary fashion with the focus not only on treatment of underlying etiology, but also on the secondary impacts of pain on the patient's life. The management of chronic pain requires special expertise. Most of the experts in chronic pain assessment and management organize themselves into pain treatment centers. These centers vary widely in their approach to the problem. The most sophisticated is a multidisciplinary center that is university-based and includes teaching and research. Treatment of chronic pain includes a variety of medications, psychological support, and rehabilitation. Multidisciplinary pain management is also an integral part of the palliative care and hospice concept used to treat cancer pain.
-
-
-
Advances in the Medical Treatment of Epilepsy
Vol. 49 (1998), pp. 135–162More LessTreatment options for epilepsy, especially using antiepileptic drugs, have increased substantially in the past five years. Since 1993, four novel antiepileptic drugs have been approved and marketed in the United States: felbamate, gabapentin, lamotrigine, and topiramate. Two others, tiagabine and vigabatrin, are likely to be approved in the near future. For many patients, these agents offer the realistic promise of improved seizure control, often with fewer adverse effects and less significant drug interactions compared with older agents. In addition, fosphenytoin, a water-soluble phenytoin prodrug with a number of advantages over intravenous phenytoin, has been released. There are new administration options for carbamazepine, diazepam, and valproic acid. For drug-resistant or -intolerant patients, there has been renewed interest in alternative therapies, especially the ketogenic diet. Taken together, these represent significant therapeutic advances that are benefiting patients with epilepsy. At the same time, improved understanding of the basic mechanisms of epileptogenesis, and of the cellular and molecular actions of available antiepileptic drugs, creates a framework for designing unique therapeutic strategies that are targeted at key sites of vulnerability involved in the development and maintenance of the epileptic state.
-
-
-
How to Screen for Colon Cancer1
Vol. 49 (1998), pp. 163–172More LessThe biology of colorectal cancer provides a unique opportunity for early detection and prevention. There is now evidence that screening of asymptomatic average-risk individuals over 50 years of age can reduce mortality resulting from colorectal cancer. New recommendations from the US Preventive Services Task Force endorse screening with fecal occult blood tests or sigmoidoscopy. The best method for population screening remains uncertain. The cost of screening is an important issue in the development of public policy. This review discusses the various screening options, examines the “downstream” effects of screening, and reviews the anticipated costs and effectiveness. Ultimately, the effectiveness of any screening program depends on patient compliance. Further research is needed to determine the best methods of enhancing patient adherence to a screening program.
-
-
-
The Role of Glutamatergic Neurotransmission in the Pathophysiology of Alcoholism
Vol. 49 (1998), pp. 173–184More LessRecent evidence suggests that ethanol abuse produces its diverse effects on the brain to a substantial degree by disrupting the function of the major excitatory neurotransmitter, glutamate. Ethanol, at concentrations associated with behavioral effects in humans, inhibits the N-methyl-d-aspartate (NMDA) receptor, which mediates the post-synaptic excitatory effects of glutamate. Tolerance to ethanol results in up-regulation of the NMDA receptor so that abrupt withdrawal produces a hyperexcitable state that leads to seizures, delerium tremens, and excitotoxic neuronal death. Ethanol's inhibition of the NMDA receptor in the fetal brain likely contributes to the CNS manifestations of fetal alcohol syndrome. Therapeutic strategies aimed at correcting glutamatergic dysregulation in alcoholism need to be explored.
-
-
-
Evaluation of the Patient with Recurrent Bacterial Infections1
Vol. 49 (1998), pp. 185–199More LessRecurrent bacterial infection is a complaint encountered regularly in the course of both adult and pediatric care. Defects of neutrophils and monocytes are most commonly associated with recurrent infection, but abnormalities of immunoglobulins and complement must be considered. Defensins, small antibacterial peptides, have been implicated recently in some of the infectious diathesis of cystic fibrosis. A thorough history and physical examination focused on severity, sequelae, and microbiology of infections can usually determine whether a patient needs further evaluation. The diseases and syndromes most frequently associated with recurrent infection are presented, along with discriminating clinical, pathologic, and microbiologic features.
-
-
-
Human Ehrlichioses: Newly Recognized Infections Transmitted by Ticks
Vol. 49 (1998), pp. 201–213More LessHuman ehrlichioses are tick-borne infections caused by bacteria in the genus Ehrlichia. Human monocytic ehrlichiosis is caused by Ehrlichia chaffeensis and human granulocytic ehrlichiosis is caused by an agent similar to Ehrlichia equi. E. chaffeensis infects mononuclear phagocytes and is transmitted by Lone Star ticks (Amblyomma americanum) found in the south central and eastern United States. The agent of human granulocytic ehrlichiosis infects mostly neutrophils, is transmitted by Ixodes species ticks, and occurs mostly in the upper midwest and northeast United States. Despite the undifferentiated presentation of both ehrlichioses with fever, headache, myalgias, leukopenia, thrombocytopenia, and elevated liver enzyme activities, the diagnostic methods are distinct. Occasional severe complications include meningoencephalitis, adult respiratory distress syndrome, shock, and opportunistic infections. Immunocompromised patients are at high risk for death. An adverse outcome is associated with delayed diagnosis and therapy; thus, empirical treatment is advocated. Treatment with doxycycline usually results in prompt defervescence and cure.
-
-
-
Surgical Implications of Obesity
Vol. 49 (1998), pp. 215–234More LessObesity is perhaps the most significant public health problem facing the United States today. Obese patients are at increased risk for numerous medical problems, which can adversely affect surgical outcome. However, these risks have not uniformly translated into increased or prohibitive operative morbidity and mortality in this population. With appropriate perioperative precautions and monitoring, the incidence of serious cardiovascular and pulmonary complications can be minimized. Obese patients can be treated as safely and effectively as their normal weight counterparts under most circumstances and should not be denied surgical treatment for any disorder when surgery constitutes the most appropriate therapy. When indicated, surgical treatment should be considered for patients with clinically severe obesity, since currently it appears to offer the best long-term results for weight control and amelioration of comorbidity.
-
-
-
Exercise, Glucose Transport, and Insulin Sensitivity
Vol. 49 (1998), pp. 235–261More LessPhysical exercise can be an important adjunct in the treatment of both non–insulin-dependent diabetes mellitus and insulin-dependent diabetes mellitus. Over the past several years, considerable progress has been made in understanding the molecular basis for these clinically important effects of physical exercise. Similarly to insulin, a single bout of exercise increases the rate of glucose uptake into the contracting skeletal muscles, a process that is regulated by the translocation of GLUT4 glucose transporters to the plasma membrane and transverse tubules. Exercise and insulin utilize different signaling pathways, both of which lead to the activation of glucose transport, which perhaps explains why humans with insulin resistance can increase muscle glucose transport in response to an acute bout of exercise. Exercise training in humans results in numerous beneficial adaptations in skeletal muscles, including an increase in GLUT4 expression. The increase in muscle GLUT4 in trained individuals contributes to an increase in the responsiveness of muscle glucose uptake to insulin, although not all studies show that exercise training in patients with diabetes improves overall glucose control. However, there is now extensive epidemiological evidence demonstrating that long-term regular physical exercise can significantly reduce the risk of developing non–insulin-dependent diabetes mellitus.
-
-
-
The Molecular Ggenetics of the Long QT Syndrome: Genes Causing Fainting and Sudden Death
Vol. 49 (1998), pp. 263–274More LessThe congenital long QT syndrome is an autosomal-dominant genetic disorder of cardiac electrical repolarization. It is caused by mutations of at least six genes, of which four, all encoding for cardiac ion channels, have been identified: KVLQT1, HERG, and Min K encode for cardiac potassium ion channels, and SCN5A encodes for the cardiac sodium ion channel. In each case the altered ion channel function produces prolongation of the action potential and propensity to torsade de pointes ventricular tachycardia. A fifth gene locus is known to be on chromosome 4, but the gene has not been isolated. At least one other gene must exist, and there may be several more. Long QT syndrome is a frequent but often overlooked cause of unexpected syncope and sudden death in children and young adults. Characteristic findings are prolongation of the QT interval and T wave abnormalities on the electrocardiogram. However, the QT interval at presentation is normal about 10% of the time and just borderline prolonged another 30%, so diagnosis may be difficult. Symptoms are syncope and sudden death, typically occurring during exercise or emotional upset. The manifestations vary, depending on the genotype present. The phenotype also probably varies, depending on the specific mutation involved. Phenotypic heterogeneity is also caused by variable penetrance and expressivity.
-
-
-
Infection Genomics: Nramp1 as a Major Determinant of Natural Resistance to Intracellular Infections
Vol. 49 (1998), pp. 275–287More LessThe scope of the tuberculosis (TB) epidemic in the world today is enormous, with about 30 million active cases. Current research into preventing the spread of TB is focused on development of new drugs to inactivate Mycobacterium tuberculosis, the causative agent of TB, as well as on identifying the critical steps of host defense to infection with Mycobacteria, which might also yield therapeutic targets. Our infection genomics approach toward the latter strategy has been to isolate and characterize a mouse gene, Bcg (Nramp1), which controls natural susceptibility to infection with Mycobacteria, as well as Salmonella and Leishmania. Through comparative genomics, we have identified the homologous human NRAMP1 gene, alleles of which are now being used for tests of linkage with TB and leprosy.
-
-
-
Gastric Lymphoma of Mucosa-Associated Lymphoid Tissue and Helicobacter pylori
Vol. 49 (1998), pp. 289–299More LessAlthough the majority of primary gastric lymphomas are of high-grade non-Hodgkin's type, a significant number are low-grade B cell lymphomas. The recognition that the majority of the latter have characteristic clinicopathological features that are different from those of their nodal counterparts has led to the suggestion that these lymphomas arise specifically from within organized extranodal lymphoid tissue; this tissue resembles that seen constitutively in the intestine (mostly located in the terminal ileum as Peyer's patches) and is termed mucosa-associated lymphoid tissue (MALT). The paradox of this proposal is that there is no MALT in the gastric mucosa in normal individuals from which a primary lymphoma can arise. However, it has been shown that organized lymphoid tissue with all the features of MALT can be acquired in the gastric mucosa, and this is seen most frequently, but not exclusively, in association with infection by Helicobacter pylori H. pylori). Subsequent studies have confirmed a close association between H. pylori infection and gastric MALT lymphoma with the infection preceding the development of the lymphoma. In vitro studies have demonstrated that there is an immunologically based drive to tumor cell proliferation in low-grade gastric MALT lymphomas associated with the presence of H. pylori. Clinical studies have shown that, at least in early lesions, eradication of the organism can result in tumor regression in 60 to 92% of cases.
-
-
-
Xenotransplantation: Problems and Prospects
Vol. 49 (1998), pp. 301–310More LessResearch in xenotransplantation has increased enormously in the last eight years. As the shortage of allogeneic organs has intensified, the possibility of using organs from pigs has become more attractive. Current data suggest that hyperacute rejection can be overcome in a clinically acceptable manner. However, additional likely rejection factors, probably related to endothelial cell activation, are being identified that likely lead to delayed xenograft rejection, a phenomenon that can occur in the absence of T lymphocytes. Reviewed here are various genetic engineering approaches that might help overcome these rejection factors, resulting eventually in a multi-transgene donor pig. Other concerns and current controversies in the field are also discussed.
-
Previous Volumes
-
Volume 76 (2025)
-
Volume 75 (2024)
-
Volume 74 (2023)
-
Volume 73 (2022)
-
Volume 72 (2021)
-
Volume 71 (2020)
-
Volume 70 (2019)
-
Volume 69 (2018)
-
Volume 68 (2017)
-
Volume 67 (2016)
-
Volume 66 (2015)
-
Volume 65 (2014)
-
Volume 64 (2013)
-
Volume 63 (2012)
-
Volume 62 (2011)
-
Volume 61 (2010)
-
Volume 60 (2009)
-
Volume 59 (2008)
-
Volume 58 (2007)
-
Volume 57 (2006)
-
Volume 56 (2005)
-
Volume 55 (2004)
-
Volume 54 (2003)
-
Volume 53 (2002)
-
Volume 52 (2001)
-
Volume 51 (2000)
-
Volume 50 (1999)
-
Volume 49 (1998)
-
Volume 48 (1997)
-
Volume 47 (1996)
-
Volume 46 (1995)
-
Volume 45 (1994)
-
Volume 44 (1993)
-
Volume 43 (1992)
-
Volume 42 (1991)
-
Volume 41 (1990)
-
Volume 40 (1989)
-
Volume 39 (1988)
-
Volume 38 (1987)
-
Volume 37 (1986)
-
Volume 36 (1985)
-
Volume 35 (1984)
-
Volume 34 (1983)
-
Volume 33 (1982)
-
Volume 32 (1981)
-
Volume 31 (1980)
-
Volume 30 (1979)
-
Volume 29 (1978)
-
Volume 28 (1977)
-
Volume 27 (1976)
-
Volume 26 (1975)
-
Volume 25 (1974)
-
Volume 24 (1973)
-
Volume 23 (1972)
-
Volume 22 (1971)
-
Volume 21 (1970)
-
Volume 20 (1969)
-
Volume 19 (1968)
-
Volume 18 (1967)
-
Volume 17 (1966)
-
Volume 16 (1965)
-
Volume 15 (1964)
-
Volume 14 (1963)
-
Volume 13 (1962)
-
Volume 12 (1961)
-
Volume 11 (1960)
-
Volume 10 (1959)
-
Volume 9 (1958)
-
Volume 8 (1957)
-
Volume 7 (1956)
-
Volume 6 (1955)
-
Volume 5 (1954)
-
Volume 4 (1953)
-
Volume 3 (1952)
-
Volume 2 (1951)
-
Volume 1 (1950)
-
Volume 0 (1932)