Pneumatosis intestinalis in adults: management, surgical indications, and risk factors for mortality

BACKGROUND

Pneumatosis intestinalis (PI) is an unusual finding that can exist in a benign setting but can indicate ischemic bowel and the need for surgical intervention. We present a series of cases of PI in adults to illustrate factors associated with death and surgical intervention.

METHODS

We reviewed the radiology database of the Mount Sinai Medical Center for cases of PI between 1996-2006 in adult patients. Chi-square and multivariable logistic regression analyses were used to identify factors significant for surgery and death.

RESULTS

Forty patients developed PI over a 10-year span. The overall in-hospital mortality rate was 20%, and the surgical rate was 35%. Factors independently associated with surgical management on multivariable analysis were age >or= 60 years (p = 0.03), the presence of emesis (p = 0.01), and a WBC > 12 c/mm3 (p = 0.03). Pre-existing sepsis was independently associated with mortality (p = 0.03) while controlling for surgery.

CONCLUSION

Patients with the concomitant presence of PI, a WBC > 12 c/mm3, and/or emesis in the >60-year-old age group were most likely to have surgical intervention, whereas PI patients with sepsis had the highest risk for death. A management algorithm is proposed, but further research will be needed to determine which patients with PI may benefit most from surgery.

Substrate pretreatment: the key to effective enzymatic hydrolysis of lignocellulosics?

Although the structure and function of cellulase systems continue to be the subject of intense research, it is widely acknowledged that the rate and extent of the cellulolytic hydrolysis of lignocellulosic substrates is influenced not only by the effectiveness of the enzymes but also by the chemical, physical and morphological characteristics of the heterogeneous lignocellulosic substrates. Although strategies such as site-directed mutagenesis or directed evolution have been successfully employed to improve cellulase properties such as binding affinity, catalytic activity and thermostability, complementary goals that we and other groups have studied have been the determination of which substrate characteristics are responsible for limiting hydrolysis and the development of pretreatment methods that maximize substrate accessibility to the cellulase complex. Over the last few years we have looked at the various lignocellulosic substrate characteristics at the fiber, fibril and microfibril level that have been modified during pretreatment and subsequent hydrolysis. The initial characteristics of the woody biomass and the effect of subsequent pretreatment play a significant role on the development of substrate properties, which in turn govern the efficacy of enzymatic hydrolysis. Focusing particularly on steam pretreatment, this review examines the influence that pretreatment conditions have on substrate characteristics such as lignin and hemicellulose content, crystallinity, degree of polymerization and specific surface, and the resulting implications for effective hydrolysis by cellulases.

Immunohistochemistry for the imprinted gene product IPL/PHLDA2 for facilitating the differential diagnosis of complete hydatidiform mole

OBJECTIVE

To determine if immunohistochemistry for PHLDA2 (also known as IPL and TSSC3), the product of a paternally imprinted, maternally expressed gene, can be used as a tool in the differential diagnosis of molar gestations.

STUDY DESIGN

Twenty-five cases (15 complete moles, 5 partial moles and five hydropic abortions) were stained by immunohistochemistry for PHLDA2 and scored (without knowledge of the diagnosis) for positivity in the villous cytotrophoblast and then compared to adjacent sections stained by p57KIP2 immunohistochemistry.

RESULTS

All partial moles and hydropic abortions were positive for PHLDA2 and p57KIP2. There was strong PHLDA2 staining of the cytoplasm in virtually all cells of the villous cytotrophoblast, while p57KIP2 was localized to the nucleus in a subset of those cells. All complete moles were negative for both markers in the villous cytotrophoblast.

CONCLUSION

Immunohistochemistry for PHLDA2 serves as a practical and reliable diagnostic marker for the discrimination of complete mole from partial mole and hydropic abortion. Since the immunohistochemical diagnosis of complete mole is based on a negative result, absence of staining, the use of both markers (PHLDA2 and p57KIP2) together could increase the level of confidence when making this prognostically important distinction.

Expression of mammalian paralogues of HRAD9 and Mrad9 checkpoint control genes in normal and cancerous testicular tissue

Human and mouse paralogues of the evolutionarily conserved mammalian HRAD9 and Mrad9 cell cycle checkpoint control genes have been isolated and called HRAD9B and Mrad9B, respectively. HRAD9B encodes a protein that is 414 amino acids long and is 55% similar and 35% identical to the HRAD9 gene product. The Mrad9B protein is 398 amino acids long and is 50% similar and 35% identical to its paralogue. We demonstrate that the encoded human protein is nuclear and can physically interact with checkpoint proteins HRAD1, HRAD9, HHUS1, and HHUS1B, much like HRAD9. Northern blot analysis to detect tissue specificity indicates that the human and mouse genes are expressed predominantly in the testis. The abundance of HRAD9B RNA, as judged by quantitative reverse transcription-PCR, is very low in most testicular tumors, particularly those of germ cell origin, i.e., seminomas, relative to normal testis control, nonseminomas, or Leydig tumor cells. RNA levels corresponding to HRAD17, another checkpoint control gene, demonstrated a similar pattern, but in general, higher quantities of this message were detected in samples. Furthermore, normal/tumor tissue differences were not as dramatic or consistent from sample to sample, especially for the seminomas. Our results demonstrate for the first time that HRAD9 and Mrad9 are part of a gene family and reveal a new genetic element encoding a product that interacts with multiple, known cell cycle checkpoint control proteins. The findings also indicate that HRAD9B can serve as a biomarker in particular for testicular seminomas and might be causally related to the disease.

Mid2p stabilizes septin rings during cytokinesis in fission yeast

Septins are filament-forming proteins with a conserved role in cytokinesis. In the fission yeast Schizosaccharomyces pombe, septin rings appear to be involved primarily in cell-cell separation, a late stage in cytokinesis. Here, we identified a protein Mid2p on the basis of its sequence similarity to S. pombe Mid1p, Saccharomyces cerevisiae Bud4p, and Candida albicans Int1p. Like septin mutants, mid2delta mutants had delays in cell-cell separation. mid2delta mutants were defective in septin organization but not contractile ring closure or septum formation. In wild-type cells, septins assembled first during mitosis in a single ring and during septation developed into double rings that did not contract. In mid2delta cells, septins initially assembled in a single ring but during septation appeared in the cleavage furrow, forming a washer or disc structure. FRAP studies showed that septins are stable in wild-type cells but exchange 30-fold more rapidly in mid2delta cells. Mid2p colocalized with septins and required septins for its localization. A COOH-terminal pleckstrin homology domain of Mid2p was required for its localization and function. No genetic interactions were found between mid2 and the related gene mid1. Thus, these studies identify a new factor responsible for the proper stability and function of septins during cytokinesis.

Critical role for the chemokine MCP-1/CCR2 in the pathogenesis of bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is the major limitation to survival after lung transplantation. Acute rejection, its main risk factor, is characterized by perivascular/bronchiolar leukocyte infiltration. BOS is characterized by persistent peribronchiolar leukocyte recruitment leading to airway fibrosis and obliteration. The specific mechanism(s) by which these leukocytes are recruited are unknown. Because MCP-1, acting through its receptor CCR2, is a potent mononuclear cell chemoattractant, we hypothesized that expression of this chemokine during an allogeneic-response promotes persistent recruitment of leukocytes and, ultimately, rejection. We found that elevated levels of biologically active MCP-1 in human bronchial lavage fluid (BALF) were associated with the continuum from acute to chronic allograft rejection. Translational studies in a murine model of BOS demonstrated increased MCP-1 expression paralleling mononuclear cell recruitment and CCR2 expression. Loss of MCP-1/CCR2 signaling, as seen in CCR2(-/-) mice or in WT mice treated with neutralizing antibodies to MCP-1, significantly reduced recruitment of mononuclear phagocytes following tracheal transplantation and led to attenuation of BOS. Lymphocyte infiltration was not reduced under these conditions. We suggest that MCP-1/CCR2 signaling plays an important role in recruitment of mononuclear phagocytes, a pivotal event in the pathogenesis of BOS.

Respiratory syncytial virus predisposes mice to augmented allergic airway responses via IL-13-mediated mechanisms

The development of severe childhood asthma may be influenced by several factors including environmental and infectious stimuli. The causal relationship between infectious viral responses, such as respiratory syncytial virus (RSV), and severe asthma during early childhood is unclear. In these studies, the ability for an initial RSV infection to exacerbate and promote a more severe asthmatic-type response was investigated by combining established murine models of disease. We examined the ability of RSV to induce exacerbation of allergic disease over a relatively long period, leading to development of severe airway responses including airway inflammation and hyperreactivity. The preferential production of IL-13 during a primary RSV infection appears to play a critical role for the exacerbation of cockroach allergen-induced disease. The depletion of IL-13 during RSV infections inhibited the exacerbation and acceleration of severe allergen-induced airway hyperreactivity. This was indicated by decreases in airway hyperreactivity and changes in lung chemokine production. These data suggest that the airway responses during asthma can be greatly affected by a previous RSV infection, even when infection occurs before allergen sensitization. Overall, infection of the airways with RSV can induce an IL-13-dependent change in airway function and promotes an environment that contributes to the development of severe allergic asthmatic responses.

Role of bud6p and tea1p in the interaction between actin and microtubules for the establishment of cell polarity in fission yeast

BACKGROUND

In many cell types, microtubules are thought to direct the spatial distribution of F-actin in cell polarity. Schizosaccharomyces pombe cells exhibit a regulated program of polarized cell growth: after cell division, they grow first in a monopolar manner at the old end, and in G2 phase, initiate growth at the previous cell division site (the new end). The role of microtubule ends in cell polarity is highlighted by the finding that the cell polarity factor, tea1p, is present on microtubule plus ends and cell tips [1].

RESULTS

Here, we characterize S. pombe bud6p/fat1p, a homolog of S. cerevisiae Bud6/Aip3. bud6Delta mutant cells have a specific defect in the efficient initiation of growth at the new end and like tea1Delta cells, form T-shaped cells in a cdc11 background. Bud6-GFP localizes to both cell tips and the cytokinesis ring. Maintenance of cell tip localization is dependent upon actin but not microtubules. Bud6-GFP localization is tea1p dependent, and tea1p localization is not bud6p dependent. tea1Delta and bud6Delta cells generally grow in a monopolar manner but exhibit different growth patterns. tea1(Delta)bud6Delta mutants resemble tea1Delta mutants. Tea1p and bud6p coimmunoprecipitate and comigrate in large complexes.

CONCLUSIONS

Our studies show that tea1p (a microtubule end-associated factor) and bud6p (an actin-associated factor) function in a common pathway, with bud6p downstream of tea1p. To our knowledge, bud6p is the first protein shown to interact physically with tea1p. These studies delineate a pathway for how microtubule plus ends function to polarize the actin cytoskeleton through actin-associated polarity factors.

SCF-induced airway hyperreactivity is dependent on leukotriene production

Stem cell factor (SCF) is directly involved in the induction of airway hyperreactivity during allergen-induced pulmonary responses in mouse models. In these studies, we examined the specific mediators and mechanisms by which SCF can directly induce airway hyperreactivity via mast cell activation. Initial in vitro studies with bone marrow-derived mast cells indicated that SCF was able to induce the production of bronchospastic leukotrienes, LTC4and LTE4. Subsequently, when SCF was instilled in the airways of naive mice, we were able to observe a similar induction of LTC4and LTE4in the bronchoalveolar lavage (BAL) fluid and lungs of treated mice. These in vivo studies clearly suggested that the previously observed SCF-induced airway hyperreactivity may be related to the leukotriene production after SCF stimulation. To further investigate whether the released leukotrienes were the mediators of the SCF-induced airway hyperreactivity, an inhibitor of 5-lipoxygenase (5-LO) binding to the 5-LO activating protein (FLAP) was utilized. The FLAP inhibitor MK-886, given to the animals before intratracheal SCF administration, significantly inhibited the release of LTC4and LTE4into the BAL fluid. More importantly, use of the FLAP inhibitor nearly abrogated the SCF-induced airway hyperreactivity. In addition, blocking the LTD4/E4, but not LTB4, receptor attenuated the SCF-induced airway hyperreactivity. In addition, the FLAP inhibitor reduced other mast-derived mediators, including histamine and tumor necrosis factor. Altogether, these studies indicate that SCF-induced airway hyperreactivity is dependent upon leukotriene-mediated pathways.

IL-13-induced airway hyperreactivity during respiratory syncytial virus infection is STAT6 dependent

Airway damage and hyperreactivity induced during respiratory syncytial virus (RSV) infection can have a prolonged effect in infants and young children. These infections can alter the long-term function of the lung and may lead to severe asthma-like responses. In these studies, the role of IL-13 in inducing and maintaining a prolonged airway hyperreactivity response was examined using a mouse model of primary RSV infection. Using this model, there was evidence of significant airway epithelial cell damage and sloughing, along with mucus production. The airway hyperreactivity response was significantly increased by 8 days postinfection, peaked during days 10-12, and began to resolve by day 14. When the local production of Th1- and Th2-associated cytokines was examined, there was a significant increase, primarily in IL-13, as the viral response progressed. Treatment of RSV-infected mice with anti-IL-13 substantially inhibited airway hyperreactivity. Anti-IL-4 treatment had no effect on the RSV-induced responses. Interestingly, when IL-13 was neutralized, an early increase in IL-12 production was observed within the lungs, as was a significantly lower level of viral Ags, suggesting that IL-13 may be regulating an important antiviral pathway. The examination of RSV-induced airway hyperreactivity in STAT6(-/-) mice demonstrated a significant attenuation of the response, similar to the anti-IL-13 treatment. In addition, STAT6(-/-) mice had a significant alteration of mucus-producing cells in the airway. Altogether, these studies suggest that a primary factor leading to chronic RSV-induced airway dysfunction may be the inappropriate production of IL-13.

CeMENT: evaluation of a regional development programme integrating hospital and general practice clinical teaching for medical undergraduates. The Community-Based Medical Education in North Thames

OBJECTIVES

To determine the feasibility and effectiveness of shared hospital and general practice clinical teaching for medical undergraduates.

DESIGN

A multifaceted approach employing quantitative and qualitative techniques.

SETTING

All medical schools in North Thames Region.

SUBJECTS

Students, GP tutors and hospital specialists.

RESULTS

The model was successfully adopted in a broad range of clinical specialties in all of the participating medical schools, resulting in a doubling of the involvement of general practice in clinical teaching. Participating students provided an overwhelmingly positive evaluation of the attachments and there was a clear perception of benefit amongst the participating GPs. However, the views of the participating hospital clinicians were less positive and the true nature and extent of the educational impact proved difficult to assess.

CONCLUSIONS

This model of collaborative clinical teaching between hospital and general practice can be implemented in accordance with the project's key aims, but the enthusiastic involvement of hospital clinicians may be difficult to secure.

Perihepatic abscess formation in diabetes: a complication of silent gallstones

Perforation of the gallbladder is a serious complication of acute cholecystitis, with significant morbidity and mortality rates. We present the case of a diabetic adult in whom the usual signs and symptoms of acute cholecystitis were obscured. A high index of suspicion at the time of admission prompted emergent evaluation. Computerized axial tomography revealed a large perihepatic abscess extending from a perforated gallbladder. Fourteen hundred milliliters of malodorous brown fluid were drained by ultrasound-guided percutaneous aspiration from the collection. Early clinical suspicion combined with conservative surgical management may prevent serious morbidity and/or mortality in diabetic patients with complicated cholecystitis.

Information about patients' deaths: general practitioners' current practice and views on receiving a death register

BACKGROUND

Although general practitioners are involved in the care of most dying patients, they do not routinely receive information about their deceased patients for whom they did not complete the death certificate, and often they rely upon informal communication channels.

AIM

This study set out to assess how general practitioners obtained, recorded and used information about deceased patients and to determine their views on receiving a death register.

METHOD

A questionnaire was sent to all 305 general practitioners in the Newcastle upon Tyne and Sunderland Family Health Services Authority areas.

RESULTS

A total of 225 questionnaires were returned (response rate 74%). General practitioners usually first learnt about their patients' deaths from hospital discharge summaries (54%) and patients' relatives (46%) and less commonly from newspaper obituary columns (20%) and hospital telephone calls (9%). Two thirds of respondents recorded information about decreased patients, mainly listing personal details and the immediate cause of death. One third or fewer of those recording information listed contributory causes. The information was used mainly for following up bereaved relatives and notifying hospitals and other agencies.

CONCLUSION

Current informal systems for handling information about patients' deaths are inadequate. General practitioners need and would welcome prompt, accurate and comprehensive information about all their deceased patients.

Toxicological testing in the European Community

This paper provides a brief overview and guide to the development of European Community regulatory policy in relation to toxicology.

Creating a death register for general practice

General practitioners complete approximately 26% of death certificates themselves but have considerable difficulty obtaining prompt and accurate information about their other patients who die. A random survey of district health authorities in England revealed that all were able to compile death lists but none included general practitioner details. This paper reviews the flow of information on patient deaths and describes a project to assess the feasibility of providing Newcastle general practitioners with comprehensive death registers. With the collaboration of the family health services authority and the district health authority, and with data from the regional perinatal mortality survey the creation each week of complete lists of patient deaths, broken down by general practitioner, is feasible. Death registers allow general practitioners to undertake audit of the quality of death certification and of the care of the recently deceased, and to improve the continuing care of the bereaved.

Audit of deaths in general practice: pilot study of the critical incident technique

OBJECTIVE

To develop and pilot a method for conducting an audit of deaths in general practice by the critical incident technique.

DESIGN

Prospective use of the technique within a primary health care team, with the aid of a facilitator, to analyse the events surrounding patients' deaths.

SETTING

One inner city academic general practice.

PARTICIPANTS

Practice team, comprising general practitioners, trainee, practice manager, practice nurse, and attached health visitor and district nurses.

MAIN MEASURES

Identification and classification of critical incidents associated with the case studies of eight recently decreased patients in the practice and subsequent impact on the practice.

RESULTS

Among the eight case studies, 57 critical incidents were identified (mean 7.1 per case, range 2 to 15). A failure of communication was the most common factor identified in incidents giving rise to concern, but positive factors in patient care were also identified. Changes in practice included developing protocols for follow up of bereaved relatives and carers and a checklist to ensure completion of administrative follow up tasks resulting from the patient's death; cases of recent deaths and terminally ill patients were reviewed monthly. The practice team found the method acceptable and felt that the discussions had provided useful opportunities for reflecting on their role in patient care.

CONCLUSIONS

The critical incident technique fulfils the needs of an audit of deaths in general practice; however, further evaluation based on more cases from different practices is now required.

Neuroendocrine response to psychological performance testing

Neuroendocrine changes associated with performance testing requiring sustained attention were assessed in eight normal male subjects. To verify whether the hormonal pattern was modified by chronic stimulation of opiate receptors, eight heroin addicts also were studied. Reaction times were similar in normal and addict subjects. In normal individuals, consistent and significant increases in plasma ACTH and beta-endorphin and in urinary epinephrine and norepinephrine were observed, whereas serum prolactin (PRL) progressively decreased over the testing period. Despite maintained performance capabilities, heroin addicts showed a blunted response of ACTH and a paradoxical decrease in endorphin levels. As the normal subjects, both epinephrine and norepinephrine in urine showed the same significant increase over baseline values. Serum PRL showed a similar trend towards decreased values over the testing period in both groups.

Trace elements in dialysis fluids and assessment of the exposure of patients on regular hemodialysis, hemofiltration and continuous ambulatory peritoneal dialysis

Forty-four elements (Al, Sb, As, Ba, Be, B, Br, Cd, Ce, Co, Cr, Cs, Cu, Eu, Ga, Au, Hf, In, Ir, Fe, La, Lu, Mn, Hg, Mo, Nd, Ni, Pb, Rb, Sm, Sc, Se, Ag, Sr, Ta, Tb, Tl, Th, Sn, W, U, V, Zn, Zr) have been determined in the dialysate for hemodialysis (HD) and fluids for hemofiltration (HF) and continuous ambulatory peritoneal dialysis (CAPD). Multiple determinations have been performed for each dialysis fluid. Several trace elements (TE) showed remarkably elevated average levels; moreover, different bathes of the same commercial product may present a wide variability in TE concentration. The data point out the pivotal role of dialysis fluids in contributing to TE imbalance in dialysis patients and allow the assessment of the potential element exposure of patients on regular dialytic treatment. Patients on HD treatment would be exposed on a weekly basis to milligrams of Al, B, Ba, Br, Cu, Fe, Ni, Pb, Rb, Sr and Zn; on HF, the highest exposures are due to Al, B, Br, Fe, Pb and Zn; on CAPD to B, Br, Fe and Zn. The weekly exposure for several TE appears to be 50- to 12,000-fold higher than the corresponding values on the amount absorbed via the diet (HD: Au, Ba, Be, Ce, Ga, La, Sc, Ta, Th, V, Zr; HF: Be, Ce, Ta, Th, V, Zr; CAPD: Au, Be, Ce, Ga, V, Zr).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary compliance: early assessment of evolving lung injury after onset of sepsis

We compared the sensitivity of dynamic (Cdyn) and static lung compliance (CL) with indicators of permeability injury in a model of septic porcine adult respiratory distress syndrome. Two groups of anesthetized ventilated swine (15-25 kg) were studied. Septic animals (Ps, n = 13) received Pseudomonas aeruginosa intravenously for 1 h, which resulted in severe adult respiratory distress syndrome. Controls (C, n = 13) received 0.9% NaCl. Cdyn, CL, bronchoalveolar lavage for protein estimation, and thermal cardiogreen extravascular lung water (EVLW) measurements were performed in seven C and eight Ps animals. Six C and five Ps animals underwent gamma camera measurement of lung-to-heart ratio (slope index) of 99Tc-labeled human serum albumin. Both Cdyn and CL decreased significantly (P less than 0.01) at 30 min and thereafter in Ps vs. C. EVLW, slope index, and bronchoalveolar protein content increased significantly (P less than 0.05) in Ps vs. C at 120, 150, and 300 min, respectively. Cdyn and CL decreased well before onset of permeability injury. These early changes may be due to release of vasoactive mediators and sequestration of neutrophils in the pulmonary capillaries and later to increases in EVLW. Measurement of Cdyn and CL represents an early means of assessing evolving lung injury in this acute septic porcine model.

Preventing percutaneous absorption of industrial chemicals: the "skin" denotation

Percutaneous absorption has received comparatively little attention in occupational health, although this route of entry has repeatedly caused occupation-related intoxications. In practice, the evaluation of skin penetration rates is far from simple. Much evidence has been obtained from studies of chemicals used for cosmetics and topical therapeutics, but the information available on compounds encountered in occupational health is limited. The data obtained from experimental studies have confirmed that the concentration, type of vehicle, skin area, skin condition, and extent of occlusion are important factors in determining the degree of percutaneous absorption, but no general model has been developed. Also, too little is known about the basic chemical properties governing the rate of penetration. Thus, prediction is difficult and bound to be rather inaccurate. Current preventive practice follows the procedure used by ACGIH and is mainly based on a "skin" denotation in official listings of chemicals to which exposure limits have been allocated. The number of substances and groups of chemicals which have received skin denotation in 17 selected countries varies between 24 and 179 and a total of 275 are listed as a skin hazard in one or more countries; ACGIH lists 143. Thus, the denotation practice varies. As an unfortunate result of these discrepancies and the dichotomy of skin denotation, the absence of skin denotation may erroneously indicate that efforts to protect the skin are unnecessary. Thus, an evaluation of skin penetration potentials should be incorporated in occupational health practice as a supplement to the official denotations.

Testing of chemicals, safety evaluation and regulation at European Community level

Regulations regarding safety of chemicals are covered by the following main programmes: health and safety at work, internal market and technical harmonization, environmental and consumer protection. The elaboration of draft Community legislation by the Commission for transmission to Council and the European Parliament requires an evaluation of the scientific data together with a determination of the technical possibilities and economic impact. Studies, scientific committees, national experts and tripartite advisory committees are used. For new chemicals premarketing testing is required for labelling. The testing scheme is described. From the legislative point of view chemical safety is considered essentially in terms of six broad categories: air and water pollution and handling of toxic wastes, classification and labelling of dangerous chemicals and preparations, limitations of use of dangerous substances and preparations, occupational health and safety measures, prevention of major industrial chemical accidents, public health measures related to dangerous chemicals. The classification and labelling of carcinogens and the regulation of the various facets of the use of lead will illustrate these regulatory procedures.

Reliability of urinary creatinine as a parameter used to adjust values of urinary biological indicators

The values of biological indicators used in biological monitoring are usually determined on spot samples of urine. In order to reduce the variations due to dilution, it is common practice to correct the values according to reference parameters, such as urinary creatinine concentration and specific gravity. The aim of the present study was to verify whether creatinine possesses the necessary characteristics for adjustment. The levels of creatinine were not influenced by diuresis, but, contrary to what was expected, the values of the metabolite showed marked intra- and interindividual variations. These data raise serious doubts as to the validity of creatinine as a parameter that can be used for adjustment purposes, and suggest that it would be advisable to ascertain for each biological indicator whether in fact adjustment is of any use. Lastly, since there was only a slight correlation between creatinine levels and specific gravity values, it is concluded that these two parameters cannot be used indifferently for adjustment.

Problems concerning the usefulness of adjustment of urinary cadmium for creatinine and specific gravity

A previous study concluded that there are some doubts as to the validity of creatinine as a parameter for adjusting the values of biological indicators determined on spot samples of urine, since it is subject to marked inter- and intraindividual variations. Furthermore, since there was only a moderate correlation between creatinine levels and specific density, it can be assumed that these two parameters cannot be used indifferently for adjustment. Nevertheless, it seemed advisable to verify whether correction of cadmium values determined from spot samples offers any practical advantages. For this purpose, 105 subjects with occupational exposure to cadmium were examined. They collected their 24-h urine and spot samples separately at 8.00 h. There was a close correlation between CdU/spot samples and CdU/24 h. The correlation index was very similar both for CdU/spot values expressed in microgram/l and for values adjusted according to creatinine or 1024 specific gravity. These results show that no particular advantages are offered by adjusting CdU according to creatinine or specific gravity.

[Behavior during the work week of biological indicators of exposure to lead]

The AA. have studied the weekly changes of haematic and urinary parameters of lead occupational exposure. For this aim, they have collected in 14 ceramic workers 3 blood samples for day and all urine samples for day and all urine samples from monday to friday. The PbB and FEP levels did not show significant variations during working week. The measurement of ALA in single urines shows that this parameter is characterized by remarkable fluctuations within the same day in all subjects examined. The correction of values by density gave negative results while the correction by creatinine decreases the daily fluctuations but only in some cases. The execution of test in urine of 24 hours seems to give the most reliable correlation with lead exposure levels because of its relative constancy during week.

Assessment of exposure to lead of the general population in the European Community through biological monitoring

The more than 10 years concern for lead in the European Community from the environmental and workplace point fo view, have lead to the adoption of a number of Directives limiting human exposure to head.Furthermore a Directive on the 'Biological screening of the population for lead' was adopted in 1977 to obtain an overall assessment of the exposure to lead of the general population. The results of this assessment are presented.