Selenium speciation in human body fluids

We examined temperature dependency of thermodynamic parameters in the interactions between hen egg-white lysozyme (HEL) and anti-HEL antibody, D1.3, and two mutant antibodies. The DeltaH degrees values appeared to decrease biphasically in the temperature range from 10 to 45 degrees C with the apparent inflection point around 30 degrees C. The DeltaG degrees calculated from the KA values showed only small differences because of entropy and enthalpy compensation. It has been argued that large negative values of heat capacity change (DeltaCp degrees), if observed, are mainly derived from hydrophobic interactions. However, the observed DeltaCp degrees values were too high to be ascribed only to hydrophobic interactions. Moreover, addition of methanol did not cause a decrease in the absolute value of DeltaCp degrees.     

Biopterin derivatives in human body fluids and tissues

Levels of biopterin derivatives in urine, serum, milk, cerebrospinal fluid, brain, and liver have been measured with the Crithidia fasciculata assay. Normal levels in serum and urine have been given and compared with those in a number of benign and malignant proliferative disorders, phenylketonuria, kidney disease, Parkinson's disease, schizophrenia, controlled epilepsy, rheumatoid arthritis, and pernicious anaemia. The active component of Crithidia factor in serum was 7,8-dihydrobiopterin. Tissue, urine, and some serum samples contained two active materials, the principal one being 7,8-dihydrobiopterin; a minor constituent was probably tetrahydrobiopterin. Serum biopterin levels following methotrexate administration were raised and subsequent administration of folic acid and 5-formyltetrahydrofolic acid further increased serum levels of biopterin derivatives; this was in contrast to the total absence of response to oral folates without prior methotrexate and to 5-methyltetrahydrofolic acid either with or without methotrexate being given.     

Spectrum of ischemic heart disease and the role of biochemical markers

An exciting era exists as a result of the introduction of novel markers of myocardial damage. The prognostic implications of troponins, even in the setting of "minor myocardial damage," are potentially of immense value to patient care. We need to take the next step and assess the outcomes of interventions in these settings. Use of new markers at triage will probably allow for more efficient and safe disposition of patients in this setting. There are many advantages and disadvantages to the current markers and many unanswered questions. Only through well-designed large clinical trials will we be able to realize the true potential of these markers.     

Amylase thermolability in body fluids

The thermolability of amylase was measured in saliva, pancreatic juice, urine, adult and neonatal sera. The mean percentage thermolability from these fluids was 100%, 99%, 87%, 44% and 23% respectively. In patients with acute pancreatitis and mumps the amylase was 84% and 83% thermolabile during the acute phase. On resolution of the pancreatitis this dropped towards normal. Patients with a pancreatic pseudocyst showed a high mean percentage thermolability (82%). These results could suggest that a component of amylase in human serum is not of pancreatic or salivary origin. In addition, this simple technique may be helpful in the diagnosis of pancreatic pseudocyst.     

Analysis of recombinant cytokines in human body fluids by immunoaffinity capillary electrophoresis

An immunoaffinity capillary electrophoresis (ICE) system for rapidly quantifying recombinant cytokines in human body fluids has been developed. Cytokines within biological fluids were labeled with a red light emitting fluorochrome and injected into the capillary. Selected cytokines were captured by immobilized antibodies on the internal surface of the capillary, and held while unbound materials were purged. The cytokines were then eluted electrophoretically in acidic buffer. Individual cytokine peaks were detected by on-line laser-induced fluorescence detection coupled to a computerized fiber-optic spectrometer, and analyzed by integration of the eluted peaks. The comparison of the results of ICE to routine assays used for these cytokines demonstrates that ICE provides a fast and accurate procedure for defining these cytokines in complex biological samples. Immunoaffinity separations can be used for any material to which a specific antibody can be raised, making this procedure applicable to a wide range of molecules of biomedical interest.     

Monitoring of bone turnover biological, preanalytical and technical criteria in the assessment of biochemical markers

A review is given summarizing the present knowledge of bone turnover markers with special emphasis on biological, preanalytical and technical criteria in the proper judgement of efficacy and limitations of the methods employed. The marker substances may be either measures of bone formation or bone resorption. Markers of bone formation are bone alkaline phosphatase, osteocalcin and the carboxyl-terminal propeptide of procollagen type I. Bone alkaline phosphatase has proved to be superior to total alkaline phosphatase activity with respect to diagnostic sensitivity and specificity. Immunochemical techniques for measuring bone alkaline phosphatase show a cross-reactivity of 14-20% with liver alkaline phosphatase. However, this does not compromise the clinical usefulness of these assays except for patients with severe liver diseases. Osteocalcin is strictly bone-specific but shows numerous disadvantages with respect to apparent instability and discordant results as obtained by different methods; however, in certain diagnostic situations (corticosteroid-induced osteopenia, absence of destroyed bone architecture) osteocalcin may serve as a sensitive bone turnover marker. The carboxyl-terminal propeptide of procollagen type I generally shows low discriminating power in the diagnosis of bone diseases. The urinary excretion of pyridinium cross-links' has been carefully evaluated so far with respect to analytical performance and clinical usefulness. This marker may be a substitute for 4-hydroxyproline measurements as the method of choice for assessment of bone resorption. There are other degradation products from the telopeptide regions of bone-derived collagen type I which are excreted into the urine (N-telopeptides, CrossLapsTM); these analytes are promising tools in the assessment of bone resorption but require further evaluation, in particular with respect to their extraskeletal clearance and putative origin outside bone. Moreover, their clinical usefulness may vary depending on the patient group examined. In contrast, the serum concentration of the cross-linked telopeptide region of collagen type I seems to lack both diagnostic specificity and sensitivity in the majority of patient groups. Tartrate-resistant acid phosphatase (as determined by the presently available methods) cannot be recommended as a routine tool for assessment of bone resorption.     

Ganglioside patterns: new biochemical markers for human hematopoietic cell lines

Acid phosphatase (EC 3.1.3.2, orthophosphoric-monoester phosphohydrolase, (acid optimum) from the budding yeast Saccharomyces cerevisiae was purified from repressed and derepressed cells. Without Triton X-100 in the extraction buffer only the constitutive or repressible active enzyme eluted from a Sepharose CL-6B column, the last step of the purification procedure. When Triton X-100 was included in the extraction buffer, an additional protein peak eluted prior to the active acid phosphatase. The material from this new peak, a glycoprotein, had no acid phosphatase activity but cross-reacted with antibodies raised against repressible acid phosphate. The tryptic fingerprints of the inactive proteins are very similar to the ones of the corresponding active enzymes. We conclude that this new glycoprotein represents an inactive form of repressible and constitutive acid phosphatase. The fact that inactive acid phosphatase can be recovered only in the presence of Triton X-100 indicates that it is membrane-bound.     

The use of biochemical markers in the diagnosis of pelvic endometriosis

The aim of this study was to evaluate CA 125 II, C-reactive protein (CRP) and serum amyloid A (SAA) and anticardiolipin antibody (aCL) concentrations for the diagnosis of pelvic endometriosis. The study population consisted of 15 women without endometriosis, as confirmed by laparoscopy (group A), and 35 patients with pelvic endometriosis diagnosed by laparoscopy or laparotomy (group B). Group B patients were divided into those at stages I and II of the disease (BI/II) and those at stages III and IV (BIII/IV). Blood samples were obtained twice during the menstrual cycle: on day 1, 2 or 3 of the cycle and on day 8, 9 or 10 of the cycle. CA 125 II and CRP concentrations were higher in group III/IV patients compared with healthy controls, mainly during the first 3 days of the menstrual cycle; SAA concentrations were also higher in this group of patients compared with healthy controls, but only during the first 3 days of the menstrual cycle. Immunoglobulin (Ig) M aCL concentrations were higher in all patients with endometriosis compared with healthy controls, mainly during the first 3 days of the menstrual cycle. It is concluded that these determinations may contribute to the diagnosis and the indication of treatment for pelvic endometriosis. Determination of CA 125 II concentrations at the beginning of the menstrual cycle may aid the diagnosis of stage III and IV endometriosis. IgM aCL appears to be associated with the presence of all stages of the disease, while SAA values are elevated in severe situations. Measurement of these molecules may therefore provide a valuable tool in the diagnosis and management of endometriosis.     

Bedside diagnostic testing of body fluids

Numerous bedside diagnostic modalities are appropriate for the practice of emergency medicine. The proliferation of sophisticated technology is likely to increase both the availability and accuracy of commercial testing products. If health care reform in the United States results in a relaxation of the CLIA regulations, there will be a rapid expansion of research and development aimed at the biotechnology market. How much this would pertain to hospital-based emergency practice remains to be seen. Cost containment pressures may act in both directions on the utilization of available bedside technology. Although these tests are often less expensive than centralized laboratory determinations, the ready availability of near-patient testing may result in an increase in use that negates the lower cost. As with other diagnostic modalities, a thoughtful, considered approach based on scientific evidence will be necessary to formulate the appropriate use of bedside testing in individual emergency practice settings.     

Extracellular calmodulin-binding proteins in body fluids of animals

We aimed to audit nosological inaccuracies in death certification in Northern Ireland and to compare performance of hospital doctors and general practitioners. Nosology is the branch of medicine which treats of the classification of disease. 1138 deaths were registered in Northern Ireland in a 4-week period commencing 3/10/94. 195 of these were either registered by HM Coroners (HMC) or required further investigation by their staff; these cases were excluded from the study. The remaining 943 were analysed for wording and formulation inaccuracies according to the revised notes (1974), Northern Ireland Medical Certificate of Cause of Death. These are issued in book form by the Registrar of Births and Deaths. The commonest inaccuracies in death certification occur in the areas of poor terminology, sequence errors and unqualified mode. One or more inaccuracies were found in 317 (33.6%) of cases. In 13 of these (4%) cases, the inaccuracies were serious enough to warrant referral by the Registrar of Deaths to HM Coroner. The numbers of general practitioners and hospital doctors were recorded, with general practitioners being responsible for 122 (38%) and hospital doctors being responsible for 195 (62%) of inaccuracies.     

The risk of exposure to potentially contaminated body fluids in urological surgery

To determine the risk of exposure to body fluids potentially contaminated with infectious organisms we instituted a prospective study of all urological procedures performed at our institution. Urological procedures were divided into 3 categories: open, cystoscopic and endoscopic surgical (transurethral resection of the prostate or bladder tumor, ureteroscopy and percutaneous procedures). We have complete data analysis on 594 consecutive patients who underwent an operation at our institution: 77 (13%) underwent an open procedure, 75 (13%) underwent an endoscopic surgical procedure and the remaining 442 (74%) underwent cystoscopic procedures. All procedures were performed by supervised house staff using universal precautions. The operating surgeon was exposed to potentially contaminated body fluids in 173 of 594 cases overall (29%). There was exposure in 17% of all open procedures, 41% of all endoscopic surgical procedures and 29% of all cystoscopic procedures. Urologists must consider themselves at high risk for exposure to potentially contaminated body fluids and take appropriate precautions.     

The role of iron in neurotoxicity: a study of novel antimalarial drugs

The antimalarial drug artemisinin and its derivatives display neurotoxicity in animal studies in vivo and in neuronal cells in vitro. Their toxicity may be due to an interaction of iron with the endoperoxide bridge of the derivative to produce toxic free radicals and/or other toxic metabolites. In this study, 0.3 microM artemether (AEM) in the presence of 2 microM haemin significantly inhibited the outgrowth of neurites from differentiating NB2a neuroblastoma cells by up to 76%. The antioxidants ascorbic acid and glutathione completely protected against this toxicity at a concentration of 100 microM. AEM was found to be partially converted to two isomeric products, which were identified as the tetrahydrofuran acetate isomer of AEM and 3alpha-hydroxydesoxyartemether.     

Changes of biochemical markers during fracture healing

Clinical diagnosis of canine nasal mite (Pneumonyssoides caninum) infection is difficult due to the mite's location in the caudal nasal cavity and frontal sinuses. The current study was performed to evaluate the efficacy of milbemycin oxime in treating dogs with nasal mite infection. A prospective open uncontrolled study included 20 dogs with case histories indicating possible nasal mite infection. Inclusion criteria consisted of either nasal mites being demonstrated (group 1, four dogs), or suspicious clinical signs with no other apparent causes, combined with eosinophilia (group 2, 16 dogs). Milbemycin oxime 1 mg/kg was given orally three times at 10-day intervals. In 17 (85 per cent) dogs, clinical signs resolved completely following milbemycin therapy; within 10 days of the first treatment in 13 cases (group 1, four dogs; group 2, nine dogs) and within 14 days in four cases. In the remaining three dogs clinical signs persisted but were diminished.     

Use of a rodent neurotoxicity screening battery in the preclinical safety assessment of recombinant-methionyl human brain-derived neurotrophic factor

Recent efforts to evaluate neurobehavioral function in adult rodents as part of preclinical safety studies have typically been directed at evaluating possible environmental neurotoxicants. With considerable basic and clinical research efforts focusing on neurotrophic factors in the treatment of various neurodegenerative diseases, the application of these neurobehavioral evaluations is expected to increase. This report describes a six-month safety study of recombinant-methionyl human brain-derived neurotrophic factor (r-metHuBDNF) in rodents that included a neurotoxicity screening battery and was undertaken to evaluate safety issues that might be anticipated in the clinical setting. R-metHuBDNF was well tolerated by rats over six months of daily subcutaneous administration at doses that exceeded the highest anticipated clinical dose by 100-fold. Although statistically significant behavioral changes were noted, they were isolated and not considered to be associated with r-metHuBDNF treatment. We conclude that the inclusion of a neurotoxicity screening battery was an important study parameter in the assessment of the preclinical safety of this neurotrophin.     

The role of complex formation in the neurotoxicity of crotoxin components A and B

Human adipose tissue was transplanted to the mouse mutant nude (nu/nu). All the grafts were accepted and contained fat cells easily distinguishable from those of the mouse. No detectable relation between the histological pictures before and after grafting was found. In some transplants nerve tissue, and in others macrophages containing fat droplets, were found. The fat tissue graft might be useful for investigation of the influence of various hormones on human fat cells.     

The role of anergy in peripheral T cell unresponsiveness

When a T cell's encounter with specific antigen results in good signaling through the T cell antigen receptor yet does not lead to a proliferative response, the T cell enters a state of nonresponsiveness, or anergy. Anergy induction can result from a number of different situations, including antigen presentation by costimulation-deficient or "non-professional" antigen presenting cells, pharmacological blocking of T cell proliferation, or chronic stimulation of the T cell receptor by antigen. Anergy is a long-lived but temporary state characterized by a profound inability of the T cell to produce IL-2. Other effector functions may be affected to variable degrees. Anergy has been characterized most carefully under in vitro conditions, but several experimental models have demonstrated that T cells can also become anergic in vivo. This mechanism for tolerance induction may help to ensure that any mature autoreactive T cells which escape thymic deletion are unable to respond to host tissues. Furthermore, an understanding of the mechanism of anergy induction will most certainly lead to beneficial clinical applications, including improving graft acceptance and avoiding such deleterious immune responses as autoimmunity and allergy.     

Simple sensitive and specific gas chromatographic method for the quantification of diltiazem human body fluids

A gas cromatographic method for the determination of the benzothiazepine diltiazem together with its major metabolite desacetydilitiazem, is described. Silylation of the desacetyl derivative separates the metabolite from the parent drug on a 1% OV-17 column and cyclopam is used as an internal reference standard. The compounds are analysed by means of a nitrogen detector which allows the determination of 10 ng/ml of both compounds in plasma. The method has been used to determine both diltiazem and its desacetyl derivative in plasma obtained from healthy volunteers after oral doses of 60-210 mg of diltiazem.     

The role of cardiac troponin T and other new biochemical markers in evaluation and risk stratification of patients with acute chest pain syndromes

Electrocochleography (ECochG) was used to evaluate cochlear function in guinea pigs with experimentally induced endolymphatic hydrops (ELH) before and after osmotic dehydration with either glycerol or urea. We surgically induced ELH in the right ears of 9 guinea pigs, while the right ears of 6 guinea pigs received a sham operation. The left ears of the 15 animals constituted the normal group. Eight weeks after surgery, summating potential (SP) and action potential (AP) amplitudes were measured prior to and following the administration of glycerol or urea. The SPs and SP/AP ratios were reduced in all groups, with no significant differences among groups or between dehydrating agents. Some of the hydropic ears, however, did show an increased AP threshold and a recruitment effect. In measurements from 6 additional animals, serum osmolarity increased more with urea than with glycerol. The guinea pig model remains valuable for investigation of ELH, even though it differs in significant respects from ELH in humans.