Apoptosis: molecular mechanism for physiologic cell death.

Molecular biology is fast becoming the wave of the future in research as well as in the clinical laboratory. This trend toward determining cell function at this level is opening up doors to new techniques in evaluating and diagnosing such diseases as AIDS and cancer. This article focuses on apoptosis or programmed cell death, its morphological characteristics, its comparison to necrosis, its occurrence in development and homeostasis of multicellular organisms, its genetic regulation, and its involvement in diseases.     

"Coelionomics": towards understanding the molecular pathology of coeliac disease.

Coeliac disease (CD) is an inflammatory disorder of the small intestine characterised by a permanent intolerance to gluten-derived peptides. When gluten-derived peptides reach the lamina propria in CD patients, they provoke specific changes in the mucosa of their small intestine. Although the susceptibility to CD is strongly determined by environmental gluten, it is clearly a common genetic disorder. Important genetic factors for CD are the HLA-DQ genes located in the MHC region on chromosome 6 [HLA-DQ2 (95%) or HLA-DQ8 ( approximately 5%) heterodimers]. So far, the only treatment for CD consists of a life-long gluten-free diet. A key question in CD is why the gluten-derived peptides are resistant to further breakdown by endogenous proteases and how, in turn, they can activate a harmful immune response in the lamina propria of genetically predisposed individuals. Four mechanisms, namely apoptosis, oxidative stress, matrix metalloproteinases and dysregulation of proliferation and differentiation, are thought to play a role in the pathophysiology of CD. Whether the genes involved in these four mechanisms play a causative role in the development of the villous atrophy or are, in fact, a consequence of the disease process is unknown. In this review we summarise these mechanisms and discuss their validity in the context of current insights derived from genetic, genomic and molecular studies. We also discuss future directions for research and the therapeutic implications for patients.     

The polymerase chain reaction: a new tool for the understanding and diagnosis of HIV-1 infection at the molecular level.

The polymerase chain reaction (PCR) is at present the most powerful analytical tool for detection of specific nucleic acid sequences. The method is based on the in vitro amplification of DNA segments before detection with conventional hybridization techniques or visualization following electrophoresis and staining. The current diagnostic methods for HIV-1 do not allow easy identification of subgroups of infected patients including infants born to seropositive mothers, individuals with delayed serological responses to the virus, infected patients with indeterminate serology results, and patients with dual retroviral infections. Furthermore, response to antiviral therapy cannot be evaluated with serological assays. The rationale for applying PCR in those situations is elaborated here. The applications of this technique for HIV-1 as a diagnostic test and for the understanding of the pathogenesis of this retrovirus are described. Potential limitations of this technique for diagnostic purposes include mainly the possibility of false-positive results due to contamination and false-negative reactions caused by Taq polymerase inhibition. Non-isotopic means for detection of amplified products have been described and should allow for a wider application of this technology. Modifications of PCR which make use of internal standards seem promising for quantitative analysis of nucleic acids. PCR has great potential for viral diagnosis but still requires further studies and better characterization.     

Computational understanding of catalyst-controlled borylation of fluoroarenes: directed vs. undirected pathway

In this work, density functional theory (DFT) calculations are performed to understand the origin of the regioselective C–H borylation of aromatics catalyzed by Co(i)/^iPrPNP and Ir(iii)/dtbpy (4,4-di-tert-butyl bipyridine). The calculation results indicate that for the Co(i)/^iPrPNP catalytic system, the undirected pathway is 2.9 kcal mol⁻¹ more favoured over the directed pathway leading to ortho-to-fluorine selectivity. In contrast, for the Ir(iii)/dtbpy catalytic system, the directed pathway is 1.2 kcal mol⁻¹ more favoured over the undirected pathway bringing about ortho-to-silyl selectivity. For Co(i)/^iPrPNP catalyzed borylation, the undirected pathway which involves steps of ortho-to-fluorine C–H oxidative addition, C–B reductive elimination, B–B oxidative addition, and B–H reductive elimination is favorable due to the electron deficient character of the ortho-to-fluorine C–H bond. For Ir(iii)/dtbpy catalyzed borylation, the directed pathway consisting of Si–H oxidative addition, B–H reductive elimination, C–H oxidative addition, B–B oxidative addition, C–B reductive elimination, Si–H reductive elimination is favored over the undirected pathway attributed to the directing effect of the hydrosilyl group. The favourable undirected pathway (ortho-to-fluorine selectivity) for Co(i)/^iPrPNP catalyzed borylation and the favourable directed pathway (ortho-to-silyl selectivity) for Ir(iii)/dtbpy catalyzed borylation could explain well the experimentally observed ortho-to-fluorine borylation of hydrosilyl substituted fluoroarenes with cobalt catalyst (J. V. Obligacion, M. J. Bezdek and P. J. Chirik, J. Am. Chem. Soc., 2017, 139, 2825–2832) and ortho-to-silyl selectivity with iridium catalyst (T. A. Boebel and J. F. Hartwig, J. Am. Chem. Soc., 2008, 130, 7534–7535).

In this work, density functional theory (DFT) calculations are performed to understand the origin of the regioselective C–H borylation of aromatics catalyzed by Co(i)/^iPrPNP and Ir(iii)/dtbpy (4,4-di-tert-butyl bipyridine).     

Advances in understanding the molecular pathogenesis of neoplastic hematologic disorders.

The 45th Annual Meeting of the American Society of Hematology was held December 6-9, 2003, at the San Diego Convention Center in California. As with past meetings, there were exciting new developments, comprehensive educational programs, and phenomenal exhibits. There was also an ever increasing ASCLS presence at the meeting, as more hematology/hemostasis educators and researchers are finding their way to this very excellent scientific meeting. A group of us who attended the meeting would like to share with our colleagues who were unable to attend some of the new information in select areas, covered in the following two articles with a third to follow in the next issue of CLS. While a comprehensive summary of the entire meeting would be desirable, the scope of the meeting makes such an endeavor unfeasible. Consequently, we have chosen the areas of myeloproliferative disorders and myelodysplastic syndromes, acute lymphocytic leukemias, and acute myelocytic leukemias.     

Narcolepsy: new understanding of irresistible sleep

Recently, low levels of a newly identified neuropeptide, hypocretin 1, were described in the cerebrospinal fluid of patients with narcolepsy. This neurochemical finding furthers our understanding of this enigmatic sleep disorder typically characterized by excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. Narcolepsy appears to be fundamentally related to abnormally regulated rapid eye movement sleep. The diagnosis of this disorder remains challenging because of multiple other conditions that can cause daytime sleepiness and the difficulties in recognizing cataplexy based on patient report. The role of hypocretins in narcolepsy is unclear but intriguing because the cell bodies are restricted to the lateral hypothalamus, a brain region long associated with sleep regulation, with neuronal widespread projections to areas including the locus ceruleus, ventral tegmental area, amygdala, and dorsal raphe. Hypocretins potentially modulate the activity of monoamines and acetylcholine, and therefore their absence leads to the multiple symptoms of narcolepsy. This article reviews the current understanding of the diagnosis and treatment of narcolepsy and discusses the possible implications of the hypocretin discovery.     

A guide to understanding the steroid pathway: New insights and diagnostic implications

Steroid analysis has always been complicated requiring a clear understanding of both the clinical and analytical aspects in order to accurately interpret results. The literature relating to this specialised area spans many decades and the intricacies of the steroid pathway have evolved with time. A number of key changes, including discovery of the alternative androgen pathway, have occurred in the last decade, potentially changing our understanding and approach to investigating disorders of sexual development. Such investigation usually occurs in specialised paediatric centres and although preterm infants represent only a small percentage of the patient population, consideration of the persistence of the foetal adrenal zone is an additional important consideration when undertaking steroid hormone investigations. The recent expanded role of mass spectrometry and molecular diagnostic methods provides significant improvements for accurate steroid quantification and identification of enzyme deficiencies. However analysis of steroids and interpretation of results remain complicated. This review aims to provide an insight into the complexities of steroid measurement in children and offers an updated guide to interpretation, of serum and urine steroids through the presentation of a refined steroid pathway.     

The new millennium laboratory: molecular diagnostics goes clinical.

Applications of nucleic acid testing in most areas of the clinical laboratory have increased rapidly. The advantages of nucleic acid testing include enhanced specificity and sensitivity, ease of sample procurement, and more rapid turnaround time compared to conventional laboratory testing methods. However, the cost of testing is usually higher due to the need for additional laboratory space, specialized equipment, safety apparel, and the need for highly trained personnel. Most nucleic acid techniques currently used in a clinical setting can be categorized as either hybridization or amplification assays. Hybridization assays, including blotting techniques and microarrays, involve the complementary binding of an oligonucleotide probe of known DNA sequence with nucleic acid derived from the patient sample. To amplify small amounts of nucleic acid, assays such as the polymerase chain reaction and branched chain DNA employ either signal amplification or exponential amplification of target nucleic acid. Clinical applications of nucleic acid testing involve the detection of genetic diseases, e.g., sickle cell anemia and Huntington disease; and identification of infectious agents, e.g., HCV and HIV; or malignancies, e.g., chronic myelogenous leukemia and Burkitt lymphoma. Quantitative molecular assays also play important roles in predicting prognosis and monitoring responsiveness to therapy.     

Medication administration errors: understanding the issues.

OBJECTIVE: This paper surveys current literature related to medication administration errors, the role of nurses in such errors, and current initiatives that are underway within New Zealand to address this aspect of patient safety. SETTING: The literature review focused on research that primarily addresses the issues related to medications that arise in tertiary care facilities. PRIMARY ARGUMENT: Medication administration errors are reported to occur in one in five medication dosages. Such events have long been scrutinised, with the primary focus being the practice of nurses and their role in medication error. Analysis of such events frequently identifies the nurse as the deliverer of unsafe practice. However, over the past few years a shift in how medication errors are understood has led to the identification of systems-related issues that contribute to medication errors. CONCLUSION: Initiatives such as the 'Quality and Safe Use of Medicines' raise the opportunity to address some of the safety related issues with a view to enhancing patient safety. A call for nurses to pre-emptively drive and contribute to these initiatives, along with the development of nursing led research, is offered.     

Thyroidectomy: understanding the potential for complications.

Thyroidectomy is a relatively common procedure. Complications may result from the surgery itself or from secondary metabolic disturbances. Medical-surgical nurses must act quickly and efficiently to detect and treat postoperative complications.     

Another step towards understanding hemophilia A molecular pathogenesis

See also Zimmermann MA, Oldenburg J, Müller CR, Rost S. Characterization of duplication breakpoints in the factor VIII gene. This issue, pp 2696–704.     

Postoperative nausea and vomiting: understanding the enigma.

Postoperative nausea and vomiting (PONV) remains one of the most common complications related to surgery and anesthesia. Referred to as the "big little problem," PONV complications range from minor patient discomfort to gastric aspiration or death. There are multiple contributing factors that stimulate the vomiting reflex in PONV; yet, no single component is typically the causative factor. It usually is a variety of factors that trigger this response. Because the causes of PONV are multifactorial, no single antiemetic medication has been 100% effective for its prevention. A thorough understanding of these factors and the pharmacology related to PONV is essential for the effective management of this common postoperative complication.