Laboratory aspects of rheumatologic disease

Assessment of laboratory values is an important function of nursing practice. Rheumatologic laboratory assessment, in particular, can be complex because few findings are actually pathognomonic. This article provides a perspective on an interpretive approach to laboratory assessment of rheumatologic disease. In conjunction with the patient's clinical status, these values can provide helpful information for monitoring or predicting the course of disease.

Antibiotic use in food animals: controlling the human health impact

Resistance to antimicrobial drugs has compromised control of many bacterial pathogens. For foodborne pathogens, the most likely source of resistance is use of antimicrobials in food-producing animals. To control the human health impact from use of antimicrobials in animals, the U.S. Food and Drug Administration (FDA) recently announced plans to assess the microbial safety of all antimicrobials intended for use in food-producing animals. This paper describes the history of antimicrobial use and regulation in animals, the public health concern, the current animal drug approval process in the United States, the international perspective, and FDA's proposed procedures to evaluate the human health impact of the antimicrobial effects associated with animal drugs intended for use in food-producing animals. The primary public health goal of the improved regulatory paradigm is to ensure that significant human antimicrobial therapies are not lost due to use of antimicrobials in food animals.

Idiopathic hemorrhagic vasculopathy syndrome in seven black rhinoceros

Idiopathic hemorrhagic vasculopathy syndrome (IHVS) was diagnosed in 7 black rhinoceros; this newly described syndrome is characterized by severe body swelling in conjunction with a rapid and profound decrease in Hct. The disorder may be acute or chronic, may recur, and is potentially fatal. Five of the rhinoceros survived an initial episode of IHVS, and 2 of these 5 survived a recurrent episode of IHVS. Two rhinoceros died during treatment of IHVS. Treatment protocols varied, but all 7 rhinoceros received broad-spectrum antibiotics, because an infectious cause was suspected. All rhinoceros also received nonsteroidal antiinflammatory drugs and supportive care. Idiopathic hemorrhagic vasculopathy syndrome has many similarities to other vasculopathies of domestic animals, such as equine purpura hemorrhagica, but it also appears to have unique identifying features. It has been hypothesized that IHVS may be an immune response to an as yet unidentified infectious agent. Thorough and extensive testing has not identified the potential causative agent, nor the factors that predispose some black rhinoceros to developing IHVS. Further research into the rhinoceros immune system is ongoing and should help elucidate the mechanisms through which IHVS develops.

Relationship between the degree of endometrial periglandular fibrosis and the presence of angiotensin-converting enzyme in the equine endometrium

Endometrial periglandular fibrosis (EPF) has been proposed as a possible aetiology for equine embryonic and fetal loss. However, the pathophysiology of EPF is not well understood. Angiotensin-converting enzyme (ACE) is found in macrophages, endothelium (during angiogenesis) and myofibroblasts at sites of fibrosis in the heart, kidneys, liver and skin in several species. An increase in local tissue ACE-binding activity appears to be a critical event in the initiation and progression of fibrosis in these tissues. The aim of this study was to investigate the correlation between ACE activity in the equine endometrium and the degree of EPF, as determined by histological evaluation and morphometry based on a collagen-specific stain. ACE-binding activity values were significantly higher in the endometrial samples with moderate EPF (modified Kenney EPF category IIB) compared with endometria in all other categories. Ultrastructurally, the fibroblasts surrounding the glandular basal laminae in modified Kenney EPF category IIB and III endometria were undergoing myofibroblastic transformation-like changes. These observations indicate a possible link between ACE activity and the onset of EPF in mares.

Policy analysis of the use of hepatitis B, Haemophilus influenzae type b-, Streptococcus pneumoniae-conjugate and rotavirus vaccines in national immunization schedules

After the development of national vaccine programmes to deliver six vaccines to infants, new vaccine adoption has been limited. Analysis of the health and economic implications of new vaccination options can help national policy-makers. Country specific quantitative policy analyses were conducted to estimate the impact of vaccination against hepatitis B (HB), Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (SP) and rotavirus. Disease burden, programme costs and the potential reduction of disease from vaccination was assessed for each vaccine. Without vaccination, these four vaccine preventable diseases contribute up to 4.1 million deaths in each successive birth cohort. Routine scheduled use of HB and Hib vaccines could prevent up to 1.7 million deaths; SP and rotavirus vaccines, an additional 1.4 million deaths, annually. The global cost per life-year saved ranged from $29 to $150 with great variation by income and economic groups. With a few exceptions for a few countries, these vaccines would cost a fraction of average per-capita gross domestic product to save a life-year. The addition of HB and Hib vaccines, should be considered for integration in all national immunization programmes. SP and rotavirus vaccines, with the given assumptions, would also be cost-effective. Proactive analysis of the economic and epidemiologic impact of these vaccines can hasten their introduction into national vaccination schedules.

Evaluation of meningococcal meningitis vaccination strategies for the meningitis belt in Africa

BACKGROUND

Although the meningococcal polysaccharide vaccine has contributed to the control of Group A meningitis in the "meningitis belt" of Africa, recurrent large outbreaks have led to questions regarding vaccination strategy. We evaluated current and hypothetical vaccination strategies for the region.

METHODS

A model was formulated to analyze the effectiveness and costs of vaccine campaigns in response to outbreaks based on 7 years of weekly incidence data from Burkina Faso. Additional models analyzed the potential impact and costs of either a 1- or 4-dose routine scheduled delivery of meningococcal polysaccharide vaccine based on data reported to the World Health Organization from 16 countries during 1948 through 1996. Vaccine efficacy, vaccination coverage and economic data from literature reviews provided model assumptions.

RESULTS

For Burkina Faso neither 1- nor 4-dose vaccination schedules would prevent >30% of meningitis cases compared with the 42% prevented through an outbreak response program of vaccinating districts, which reach an incidence of 15 per 100000 persons for 2 weeks. For the entire meningitis belt, routine coverage with the 1- or 4-dose schedule meningococcal vaccine would require 4.9 and 19.6 million doses annually, respectively, for an annual net cost of $4.4 to $12.3 million and prevent an average 10300 to 12600 cases (23 to 28%), assuming a long term vaccine efficacy of 50%. In addition an initial "catch-up" campaign costing up to $72 million to vaccinate the population from 1 to 30 years of age would be required before achieving that level of effectiveness.

CONCLUSION

Given the relatively poor routine vaccination coverage in this region, current strategies of vaccination campaigns that achieve higher coverage would generally be more effective and less costly than the modeled routine scheduled programs, assuming that campaigns can be rapidly implemented. Until a better vaccine is available, countries in this region would be more efficient in improving the response times to outbreaks, perhaps through improved surveillance, and in bolstering existing vaccination infrastructures rather than embarking on strategies of questionable effectiveness.

An FDA review of sulfamethazine toxicity

Recently, changes have been proposed in the criteria historically used in the evaluation of the applicability to humans of some of the results obtained from the rodent carcinogenicity bioassay data. These questions center on the suitability of the rodent model for agents that exert their toxic effects via specific enzyme interactions and endocrine mechanisms which appear to be inoperative within humans. Within the U.S. Food and Drug Administration (FDA), this issue has been brought to the forefront of concern with the recent application for a New Animal Drug Application for sulfamethazine (SMZ). A panel of FDA experts from the National Center for Toxicological Research (NCTR), the Center for Veterinary Medicine (CVM), and the Center for Food Safety and Applied Nutrition has reviewed the sum of the scientific evidence available on the toxicology of SMZ. They noted that, in previous feeding studies at NCTR, high doses of SMZ were associated with significant incidences of thyroid tumors in mice and rats. The panel also notes that the tumorigenic activity of SMZ in rodents was due to its goitrogenic activity, resulting in constant stimulation of the thyroid by TSH. Humans, on the other hand, were found to be insensitive to the SMZ-like inhibition of thyroid function. Further, apart from X-irradiation and radioactive iodine, there are no other physical or chemical agents known to cause thyroid tumors in humans. Thus, the expert panel concludes that the best scientific information available indicates that elevated levels of TSH and the consequent thyroid tumors would not be produced under approved use conditions of SMZ. This conclusion is in agreement with recommendations made by three other panels, viz. the World Health Organization, the U.S. Environmental Protection Agency, and CVM, which also evaluated the public health risk of SMZ.

Management implications of evaluating the N2 and N3 neck after organ preservation therapy

OBJECTIVES/HYPOTHESIS

To determine if metastatic squamous cell carcinoma with proliferative potential persists in N2 and N3 necks after conventional radiation.

STUDY DESIGN

Retrospective case series.

MATERIALS AND METHODS

We identified 17 patients from our head and neck tumor database who underwent organ-preserving radiotherapy for primary aerodigestive squamous cell cancer and N2-3 regional metastasis. Archival tissue from these 17 neck specimens was evaluated for routine histopathologic evidence of tumor, as well as immunohistochemically for cytokeratin and Ki-67 activity. An assay for apoptosis was also performed on 10 of the specimens.

RESULTS

Routine H&E evaluation suggested metastatic cancer in 11 of 17 irradiated neck specimens. Cytokeratin immunostaining confirmed squamous cell carcinoma in these 11 necks as well as 1 additional specimen that had tested H&E negative. Ki-67 staining demonstrated proliferating tumor in 3 of 17 necks. The apoptosis assay confirmed regions of apoptosis in all of the specimens analyzed.

CONCLUSIONS

The discovery of proliferating cancer cells in 3 of 17 irradiated specimens (18%) supports the practice of planned neck dissection after primary radiotherapy for patients with pretherapeutic N2+ metastatic disease.

Preservation of noradrenergic neurons in the locus ceruleus that coexpress galanin mRNA in Alzheimer's disease

Galanin (GAL) innervation is hypertrophied in the basal forebrain and cortex of patients with Alzheimer's disease (AD). Increased GAL could exacerbate the cognitive and behavioral deficits of AD because GAL acts as an inhibitory modulator of cholinergic and noradren-ergic neurotransmission. The locus ceruleus (LC) may be a source of increased GAL in AD because (a) GAL is coexpressed in a subset of LC neurons, (b) GAL expression is up-regulated with neuronal injury, and (c) the LC undergoes extensive degeneration in AD. Therefore, we have used in situ hybridization histochemistry to measure GAL gene expression in the LC of AD patients and sex- and age-matched nondemented controls. Despite the extensive loss of norepinephrine neurons with AD, GAL mRNA-expressing neurons in the LC did not differ between groups. This resulted in a significant increase in the percentage of neuromelanin-pigmented cells that coexpressed GAL in AD patients compared with controls. These findings raise the possibility that the increased incidence of GAL expression among remaining LC neurons contributes to the hyperinnervation of GAL fibers in AD. Furthermore, GAL may be neuroprotective in the LC.

Structural relaxation in atomic clusters: master equation dynamics

The role of the potential energy landscape in determining the relaxation dynamics of model clusters is studied using a master equation. Two types of energy landscape are examined: a single funnel, as exemplified by 13-atom Morse clusters, and the double funnel landscape of the 38-atom Lennard-Jones cluster. Interwell rate constants are calculated using Rice-Ramsperger-Kassel-Marcus theory within the harmonic approximation, but anharmonic model partition functions are also considered. Decreasing the range of the potential in the Morse clusters is shown to hinder relaxation toward the global minimum, and this effect is related to the concomitant changes in the energy landscape. The relaxation modes that emerge from the master equation are interpreted and analyzed to extract interfunnel rate constants for the Lennard-Jones cluster. Since this system is too large for a complete characterization of the energy landscape, the conditions under which the master equation can be applied to a limited database are explored. Connections are made to relaxation processes in proteins and structural glasses.

Angiogenic growth factors in preinvasive breast disease

Recently, we showed that preinvasive breast pathologies, such as usual hyperplasia, atypical hyperplasia, and carcinoma in situ, have an increased vascularity when compared with normal breast tissue (S. C. Heffelfinger et al., Clinical Cancer Res., 2: 1873-1878, 1996). To understand the mechanism of this increased vascularity, we examined by immunohistochemistry each of these pathological lesions for the expression of angiogenic growth factors. These studies showed that normal breast tissue contains numerous angiogenic agents, particularly vascular endothelial cell growth factor and basic fibroblast growth factor. At the transition from normal epithelium to proliferative breast disease, insulin-like growth factor (IGF) II expression was increased, primarily in the stroma and infiltrating leukocytes. However, among proliferative tissues, IGF I decreased with increasing vascularity. Finally, both epithelial vascular endothelial growth factor and epithelial and leukocytic platelet-derived endothelial cell growth factor increased at the transition to carcinoma in situ, whereas stromal and leukocytic basic fibroblast growth factor were elevated only in invasive carcinoma. Therefore, during histological progression there is also a complex progression of angiogenic growth factors. For CIS, two forms of vascularity are found: stromal microvascular density (MVD), and vascularity associated with the epithelial basement membrane (vascular score). There was 35% discordance between these two measurement systems. Among carcinoma in situ cases, decreases in stromal IGF II were associated with increasing vascular scores but not MVD, and increases in platelet-derived endothelial cell growth factor were associated with increasing MVD but not the vascular score. The presence of discordance and differential association with specific angiogenic agents suggests that these two forms of vascularity may be differentially regulated.

Immunolocalization of transforming growth factor alpha and epidermal growth factor receptor in lungs of patients with cystic fibrosis

Transforming growth factor alpha (TGF-alpha) is expressed in respiratory epithelial cells and alveolar macrophages during development and following lung injury. In the present study, the presence and sites of synthesis of TGF-alpha and its receptor, the epidermal growth factor receptor (EGF-R), were assessed in lung tissue from patients with severe lung disease caused by cystic fibrosis (CF). Lung sections from 24 individuals with CF, obtained at the time of lung transplantation, were compared to lung sections from five lung donors without CF. Cellular sites of TGF-alpha, EGF-R, and cellular sites of proliferation were assessed by immunohistochemistry. All CF lung sections contained multiple cell types with detectable TGF-alpha. Compared to control sections, intensity of TGF-alpha immunostaining in macrophages, airway epithelial cells, and peribronchial submucosal cells was increased. EGF-R was detected in respiratory epithelial and peribronchial stromal cells but not in alveolar macrophages. The intensity of EGF-R staining in CF lung tissue did not differ from that of controls. An increased number of cells expressing Ki-67 nuclear antigen was detected in peribronchial submucosal cells but not bronchiolar epithelial cells in the CF lungs. The increased expression of TGF-alpha in CF lung tissue supports the concept that TGF-alpha plays a role in paracrine/autocrine regulation of lung remodeling associated with injury and repair in the lungs of individuals with cystic fibrosis.

Selective embolization of bleeding renal angiomyolipoma in pregnancy

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Galanin antagonizes vasopressin-stimulated flank marking in male golden hamsters

Microinjection of vasopressin (VP) into the anterior hypothalamus (AH) of golden hamsters induces a rapid bout of flank marking, a stereotyped scent marking behavior used for olfactory communication. In rats, VP is colocalized with galanin (GAL) in several brain regions. GAL has been shown to antagonize the postsynaptic actions of other cosecreted neurotransmitters including acetylcholine and norepinephrine; however, the ability of GAL to modulate the postsynaptic actions of VP has not been assessed. Here, we report that coadministration of GAL can block VP-induced flank marking in golden hamsters in a dose dependent manner. These findings provide the first evidence in any species that GAL can antagonize the central actions of VP. Using slice binding and receptor autoradiography, we have identified GAL binding sites in the AH and two other regions implicated in flank marking behavior (the lateral septum and central grey). These findings raise the possibility that endogenous GAL may function as an inhibitory modulator of this stereotypic scent marking behavior.

Simple strategy for direct identification of medically important yeast species from positive blood culture vials

We compared direct inoculation of the Auxacolor yeast identification system from positive blood culture vials to standard identification with the API 20C AUX (API 20C), using 44 prospectively collected clinical specimens and 25 seeded blood culture vials. Direct inoculation of the Auxacolor system was accurate and more rapid than standard identification with the API 20C.

Leptin binding in the arcuate nucleus is increased during fasting

The arcuate nucleus (ARC) mediates the anorexic effects of leptin and expresses the long form (Ob-Rb) of the leptin receptor. To determine whether ARC leptin binding increases when plasma leptin levels are low during fasting, [125I]-leptin specific binding to rat brain slices was measured by quantitative autoradiography. [125I]-leptin specific binding was dense in the ARC and increased 2-fold after a 48-h fast (P<0.001). These findings suggest that leptin receptor binding in the ARC is upregulated during fasting and that fasting changes the sensitivity of the ARC to leptin.

Platelet sodium/hydrogen exchanger activity in normotensives and hypertensives

Increased activity of sodium/hydrogen exchange provides a potentially important mechanism for the development of hypertension. The aims of this study were to compare platelet sodium/hydrogen exchanger activity and renal acid-base excretion in normotensives and hypertensives of Caucasian origin. Platelet intracellular pH (pHi) was measured using the fluorescent dye BCECF to monitor intracellular pH. Sodium/hydrogen exchanger activity was estimated from the recovery of pHi clamped to 6.25 with nigericin. Normotensives had supine blood pressures of < 140 and < 90 mmHg; those with essential hypertension had blood pressures > 150/95 mmHg with no known secondary cause. Measurements of platelet pHi and sodium/hydrogen exchanger activity were made on 26 normotensives (ten female, sixteen male) and 25 hypertensives (five female, twenty male). All subjects were on their usual dietary sodium intake. Statistical analysis was by two-way analysis of variance for gender and blood pressure status. Group values are expressed as means+/-SD and a P value of < 0.05 was taken as being statistically significant. There were no significant differences in platelet pHi between the normotensive (n = 26) and the hypertensive (n = 25) group: pHi 7.21+/-0.14 and 7.18+/-0.16, respectively. The pHi recovery after acidification was sodium-dependent and inhibited by N-hexamethylene amiloride. Comparison of kinetic constants showed no significant differences between the normotensive and the hypertensive groups: values for rate constants and initial velocities were 0.24+/-0.04 s(-1), 0.16+/-0.03 dpHi/s for the normotensives and 0.25+/-0.05 s(-1), 0.16+/-0.03 dpHi/s for the hypertensives, respectively; there were also no significant differences in proton fluxes. The inability to find raised platelet sodium/hydrogen exchanger in the hypertensives contrasts with previous observations using other methods for the measurement of this exchanger in platelets and this raises important methodological issues in the assessment of platelet sodium/hydrogen exchanger activity.

Lack of transmission of vancomycin-resistant enterococci in three long-term-care facilities

Three patients colonized with vancomycin-resistant Enterococcus were admitted to one or more of three long-term-care facilities. Six point-prevalence surveys revealed no transmission of vancomycin-resistant Enterococcus after a total of 234 days of exposure during which moderately strict infection control measures were implemented. Four of 116 environmental cultures were positive.