Carassius auratus as a bioindicator of the health status of Lake Trasimeno and risk assessment for consumers

Fish are good bio-indicators of the health status of the aquatic environment and can be used as biomarkers to assess the aquatic behavior of environmental pollutants, the exposure of aquatic organisms, and the health risk for consumers. Goldfish are a significant bioindicator in the Lake Trasimeno aquatic system (Umbria, Italy). This study aimed to characterize the health status and the chemical and biotic contamination of Lake Trasimeno to define its anthropogenic and natural pressures and the risk associated with consuming its fishery products. 114 determinations were performed on Carassius auratus samples from 2018 to 2020, and the occurrence of brominated flame retardants, non-dioxin-like polychlorinated biphenyls, heavy metals, and microplastics was analytically investigated. Dietary exposure assessment, risk characterization, and benefit-risk evaluation were performed for schoolchildren from 3 to 10 years old. Flame-retardants registered high levels of non-detects (99% for polybrominated diphenyl ether and 76% for hexabromocyclododecanes), while polychlorinated biphenyls were found in all samples with a maximum level of 56.3 ng/g. Traces of at least one heavy metal were found in all samples, though always below the regulatory limit. Microplastics were found with a 75% frequency of fish ingesting at least one particle. Dietary exposure and risk characterization reveal negligible contributions to the reference values of all contaminants, except for mercury, which reached up to 25% of admissible daily intake. The benefit- risk assessment highlighted that the benefits of freshwater fish intake outweigh the associated risks. The examination of goldfish as indicator fish reveals the quality of Lake Trasimeno's aquatic environment and the safety of its products.

Eustrongylides spp. parasite risk management in Atherina boyeri from Lake Trasimeno

Atherina boyeri is the primary source of fishing profit in Lake Trasimeno and a common host for Eustrongylides spp. larvae. The presence of Eustrongylides in fish is a public health concern, and effective risk management procedures are necessary to guarantee that infected products do not reach the market. Currently, in the European Union, there is no official sampling plan for fresh fish that defines sample size, inspection methods, and criteria for accepting or rejecting the product. An approach to Eustrongylides risk management is proposed in this study. A total of 270 batches of A. boyeri, each consisting of 29 specimens, were collected and examined visually in 3 years (2020-2023). The prevalence of the parasite was 20% in 2020, and in the first months of 2021, it grew up to ⁓40%, then dropped to 12.50% in December 2021 and settled at 16% in February 2022. In January and February 2023, the prevalence fell below 1%. The mean abundance was calculated and used to establish a threshold value to determine fish marketability. In 2020 and 2021, several batches were judged not marketable, and in some batches, a freezing treatment was implemented to ensure the inactivation of the parasite. In the last months of 2022 and in January and February of 2023, the presence of parasites in captured fish was negligible, and this allowed the marketability of fish as fresh. The proposed sampling plan was effective in preventing the commercialization of potentially hazardous products.

Risk Characterization and Benefit-Risk Assessment of Brominated Flame Retardant in Commercially Exploited Freshwater Fishes and Crayfish of Lake Trasimeno, Italy

Among brominated flame retardants (BFRs), polybrominateddiphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were the most widely used in past decades. BFRs not being chemically bonded to polymers means they can easily leach from the products into the environment and bioaccumulate. Humans are exposed to flame retardants mainly through food consumption, especially fish and fish products. In the present study, the occurrence of PBDEs and HBCDs in freshwater fishes and crayfish from Lake Trasimeno (Umbria region, central Italy) was assessed according to monitoring plans recommended by European competent authorities. The dietary exposure of the central Italian population to such molecules was calculated, and the risk characterization and the benefit–risk evaluation were also assessed. A total of 90 samples were analyzed by means of gas and liquid chromatography associated with triple quadrupole mass spectroscopy. A total of 51% of samples were found positive for at least one of the congeners; the most frequently found molecule was BDE-47. The data on dietary exposure ranged from 0.138 to 1.113 pg/kg body weight/day for ∑PBDE and from 0.805 to 0.868 pg/kg body weight/day for ∑HBCD. The data show no health risks for the central Italian population consuming freshwater fish products from Lake Trasimeno in relation to exposure to PBDE and HBCD.

Detection of environmental contamination with feline and canine parvoviruses: new perspectives and challenges

AIMS

To develop a protocol for environmental sampling to detect parvoviruses of dogs and cats in the environment.

METHODS AND RESULTS

Environmental contamination was carried out using different dilutions of parvovirus-contaminated materials; further field samplings were performed in areas in which clinical cases of parvovirus infections were present. Sterile cotton swabs and sponges for microbial surface sampling were used. Viruses were detected in these samples with different methods: conventional PCR, nested PCR and real-time PCR, detecting viral DNA; virus isolation, detecting infectious virus; and a commercial rapid enzyme immunoassay, detecting viral antigen. No substantial differences were observed in the two sampling methods, although the sponge was more convenient for sampling rough surfaces. Molecular assays were the most sensitive methods, identifying even very low amounts of viral DNA (up to 10 copies of viral DNA/10 µl of sample). Virus isolation and the rapid test detected the viruses only at the highest viral concentrations, both in the experimental setting and field conditions.

CONCLUSIONS

Environmental sampling and molecular protocols were effective in detecting environmental contamination with parvoviruses.

SIGNIFICANCE AND IMPACT OF THE STUDY

The protocol will be useful to identify possible sources of infection and to assess the efficacy of disinfection protocols in the environment.

Nutritional Value and Contaminant Risk Assessment of Some Commercially Important Fishes and Crawfish of Lake Trasimeno, Italy

The aim of our study was to describe the balance between health benefits and risks associated with the consumption of crawfish and nine fish species from lake Trasimeno. We thus determined both fatty acid profiles (particularly, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids) and chemical pollutants (some polychlorinated biphenyls, pesticides, and heavy metals) in fish muscle tissues. The contents of all fatty acids varied significantly among species. Sand smelt, carp, and tench, which have a high fat content, contained considerable amounts of EPA and DHA; lean fish, like perch, pike, and largemouth bass, which have relatively high percentages of the predominant n-3 fatty acids EPA and DHA, showed lower amounts of these fatty acids because of their low lipid contents. Some species contributed strongly to the Dietary Reference Intake (RDI) of EPA and DHA. The contribution of lean fish to the RDI of EPA and DHA was more limited. The concentrations of all contaminants in fish muscle tissues were lower than the regulatory limits, demonstrating the safety of the environmental conditions of the lake. The contribution to health-based reference values and benefit–risk quotients indicated that the health benefits of consumption of fish from lake Trasimeno outweigh the potential risks.

Nutritional quality, safety and sensory properties of smoked tench (Tinca tinca) pâté from Trasimeno Lake, Italy

The present study evaluated the safety, nutritional and sensory properties of fish pâtés made from smoked tench (Tinca tinca) pulp. Two formulations of tench pâté were produced, one of which included olive oil and the other contained mascarpone cheese. The prepared pâté jars were thermally treated according to the method applied in the canning industry. The inactivation of Clostridium botulinum during thermal treatment was determined through a challenge test study, demonstrating the complete depletion of targeted bacteria. Tench pâtés showed high nutritional properties, especially the formulation with olive oil, which was characterised by lower contents of cholesterol and saturated fatty acids and a high level of monounsaturated fatty acids. The two experimental formulations possessed a specific sensory profile, due to the ingredients incorporated into the products. Consumers’ evaluation established differences in the acceptance of the two products: the formulation with added olive oil was more appreciated by consumers, who displayed a higher purchase intent for this product. The study suggests that minced smoked tench is not only a promising ingredient for pâté production but that it also represents a value-added product able to contribute to freshwater food consumption.

On the Clinical Usefulness of the Free-to-Total Prostate-Specific Antigen Ratio

The free-to-total prostate-specific antigen ratio (F/T PSA) is associated with the presence of prostate cancer and is thus used as an indicator for suspicion of prostate cancer and as a determinant for biopsy. We reviewed a recent retrospective series of 966 consecutive prostate biopsies where F/T PSA was blindly determined and did not influence biopsy indication. We simulated the association of F/T PSA with biopsy outcome and its impact as a biopsy determinant. When adopting an F/T PSA cutoff of 10%, 13%, 16% or 20% among random sextant biopsies in the 4–10 ng/mL total PSA range, the sensitivity was 15%, 37%, 55% and 72% and the specificity 89%, 80%, 64% and 44%, respectively. Using F/T PSA as a biopsy determinant, from 1.7 to 2.6 cancer biopsies would have been delayed to avoid 10 benign biopsies. As this balance is not acceptable, F/T PSA has no role as a biopsy indicator and its clinical use is questionable.

Interchangeability and Diagnostic Accuracy of Two Assays for Total and Free Prostate-Specific Antigen: Two not Always Related Items

The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers’ instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.

Free DNA in Urine: A New Marker for Bladder Cancer? Preliminary Data

The aim of the present preliminary study was to investigate the presence of free DNA (FDNA) in urine as a possible marker for the diagnosis of bladder cancer. Naturally voided morning urine specimens were collected from 57 patients with suspected bladder cancer before cystoscopy. A standard urine test was performed; the specimens were then processed in order to obtain a quantitative evaluation of the presence of free DNA in the urine. Twenty-two patients were excluded from the study because they had leukocyturia and/or bacteriuria. Free DNA concentrations higher than 250 ng/mL were found in all 16 patients showing bladder cancer at cystoscopy and in seven (36.8%) of the 19 patients with negative cystoscopy. Urinary FDNA seems to have an excellent sensitivity: we observed no false negative cases and 36.8% false positive cases. By contrast, only 6.25% of the bladder cancer patients had positive urine cytology. Our results seem promising, although further studies and larger numbers are needed to define urinary free DNA as a reliable marker of bladder cancer.

Occurrence of Parasites of the Genus Eustrongylides spp. (Nematoda: Dioctophymatidae) in Fish Caught in Trasimeno Lake, Italy

Eustrongylides spp. is considered a freshwater fish zoonotic nematode. In the present study, the prevalence of Eustrongylides spp. in six edible fish (European perch - Perca fluviatilis, goldfish - Carassius auratus, largemouth black bass - Micropterus salmoides, tench- Tinca tinca, carp - Cyprinus carpio and sand smelt - Atherina boyeri) of Trasimeno lake was surveyed. The investigations were conducted from October 2014 to September 2015 and 384 specimens per species for each season were caught in Trasimeno lake and examined for the presence of larvae in the abdominal cavity and muscle. The presence of nematodes in the abdominal cavity and musculature was revealed in three fish species. The prevalence of Eustrongylides spp. infection was 6.84, 1.89 and 0.13% in perch, largemouth black bass and sand smelt, respectively. The number of parasites per fish was only one in largemouth black bass and sand smelt and ranged from one up to three in perch. This study states that the European perch, largemouth black bass and sand smelt of Trasimeno lake are infected with zoonotic parasites; therefore, food business operators have to take appropriate measures to guarantee the health of consumers.

Thermal Inactivation and Growth Potential of Listeria Monocytogenes in Smoked Tench

An experimental study for the evaluation of Listeria monocytogenes inactivation during a hot smoking process in tench was performed using Listeria innocua strains. Furthermore, the survival of L. monocytogenes in smoked tench was determined after post-processing in contaminated samples, evaluating the growth potential during storage. L innocua was not detected after the smoking process. In the challenge test, the growth potential of L. monocytogenes was 5.68 log colony forming unit g-1. The results showed that hot smoking at an inner temperature around 72°C is able to eliminate the microorganism. Nevertheless, the product is able to support the growth of the pathogen if post-process contamination occurs, as the food is suitable for Listeria multiplication. Product recontamination should be prevented by means of appropriate application of hygiene measures.

Cathepsin L increased level upon Ras mutants expression: the role of p38 and p44/42 MAPK signaling pathways

The involvement of Ras and three major Ras effectors, Raf, phosphatidylinositol 3-kinase (PI3K) and Ral guanine nucleotide exchange factor in the regulation of lysosomal proteases cathepsin L and B in human fibroblasts was compared. We found that cathepsin L cell content was increased by active Ras overexpression through Raf- and PI3K-mediated signaling pathways, while cathepsin B processing was altered by active Ras overexpression. Cathepsin L increased level following active Ras overexpression correlates with an increase of p38 MAPK activation and content and with an increase of p44/42 MAPK activation, so we investigated the role of these signaling pathways using pharmacological inhibitors. Unexpectedly, the p38 MAPK inhibitor SB203580 produced an increase of cathepsin L content, while the p44/42 MAPK signaling cascade inhibitor U0126 produced a remarkable shift of cathepsin L processing in favor of procathepsin L. In both cases, cathepsin B level and processing were not affected. The analysis of CTSL1 gene transcript demonstrated that cathepsin L protein and transcript correlate both in fibroblasts expressing Ras mutants and in pharmacologically treated cells, thus indicating a transcriptional up-regulation.

[A follow-up study to assess stress and burnout in healthcare workers. Preliminary data]

To compare data obtained in a pilot study (2002) which evaluated the risk from exposure to stress and burnout in health care workers, the same three subjective questionnaires were administered: the Job Content Questionnaire (JCQ), the State-Trait Anxiety Inventory (STAI), the Maslach Burnout Inventory (MBI). The evaluation considered 294 workers employed in eight units: two of the six previous units were reorganized in four subunits. Preliminary data showed that questionnaires' scores have a concordant trend in the different units, as observed in 2002, confirming the validity of the instruments adopted. Results indicated a decreased level of the perceived stress in all the units, especially in the Third Division. We can hypothesize that the new organization, workers' turnover during the 5 years and the effect due to individual variables could have contribute to the observed variation. No significant associations, compared to 2002, between questionnaires' scores and task were found. Further evaluations, including measurement of objective parameters, will be carried out to complete the follow-up study and to determine which variables could have a role in the variation of the levels of stress and burnout's subjective perception.

In vivo mechanical and in vitro electromagnetic side-effects of a ruminal transponder in cattle1,2

This work was undertaken to assess the long-term impacts of a ruminal transponder, used for electronic identification, on ruminal motility and on health and performance of cattle, as well as to study the electromagnetic effects on ruminal bacteria in vitro. A passive transponder (51.4 g, 67 x 17 mm) was delivered into the forestomachs of 8 calves, 32 bulls, 10 heifers, and 40 dairy cows. Final readability was 87.5% in calves, 96.9% in bulls, 90% in heifers, and 100% in cows at 481, 360, 650, and 601 d, respectively, after transponder administration. The transponder did not affect production or reproduction of cows over a 2-yr period, or performance of bulls, or mortality compared with control animals. Chewing movements per bolus were lower (P <0.01) in treated animals than in controls (49.6 vs. 52.2, 51.2 vs. 63.6, and 57.0 vs. 59.7 for bulls, heifers, and cows, respectively). Regurgitation frequency (number of boluses/10 min) tended to be greater in treated cattle: 12.4 vs. 11.3 (P = 0.07), 11.3 vs. 10.6, and 11.3 vs. 10.7 (P = 0.08) for bulls, heifers, and cows, respectively. Rumination patterns of calves fitted with transponders within the first weeks of life were similar to controls. During the experiment, 43 treated animals (8 calves, 29 bulls, and 6 cows) were slaughtered. Thirty transponders were localized in the reticulum (3 calves, 24 bulls, and 3 cows), 11 in the rumen (4 calves, 4 bulls, and 3 cows), and 2 were not recovered (1 calf and 1 bull). Within the calves, 57% of the boluses were found in the rumen. In 8 reticula (2 calves and 6 bulls) and 1 rumen (1 cow), an impression left by physical contact of the transponder was observed, although histological examination did not reveal specific lesions in the mucosa of the dystrophic areas. In strained, whole ruminal contents incubated in vitro, pH values were lower after 24 and 48 h (P <0.001) of continuous exposure to an electromagnetic field induced by the transponder-reading system. After 48 h of incubation, total bacterial numbers and NH3-N concentration were greater (P <0.001) in exposed flasks than in controls. These data indicate that the transponder may alter, via mechanical action, the reticuloruminal mucosa and rumination patterns. Furthermore, the transponder may increase, via its electromagnetic action, the growth rate and metabolic activity of ruminal bacteria.

Human herpesvirus-6B active infection associated with relapsing bilateral anterior optic neuritis

BACKGROUND AND OBJECTIVES

Human herpesvirus-6 (HHV-6) is the causative agent of exanthem subitum. Both HHV-6 variants, A and B, have been associated with central nervous system (CNS) diseases, suggesting a wide neuropathogenic potential. We describe a case of recurrent bilateral anterior optic neuritis with HHV-6 active infection associated with clinical relapses.

CASE REPORT

A 23-year old woman presented with progressive visual impairment, bilateral papillitis and painful ocular movements. Nested polymerase chain reaction (PCR) for DNA viruses, HHV-6 variant specific real time quantitative PCR, serological analysis and retrotranscription PCR (RT-PCR) for HHV-6 mRNA transcripts were performed. Nested PCR in PBMC and CSF samples was negative for all viruses but positive for HHV-6 DNA, subtyped as HHV-6B. The disease had a relapsing/remitting course. During relapses PBMC samples remained positive for HHV-6 DNA, and HHV-6 active infection was confirmed by the presence of anti-HHV-6 IgM and of HHV-6 U27 mRNA transcript. High viremia levels and relapses were overlapping. After the last relapse, the patient was successfully treated with gancyclovir.

CONCLUSIONS

The case reported here suggests a possible association of HHV-6 in bilateral optic neuritis. HHV-6 could be monitored when bilateral optic neuritis is identified, in order to establish an appropriate antiviral therapy.

On the clinical usefulness of the free-to-total prostate-specific antigen ratio

The free-to-total prostate-specific antigen ratio (F/T PSA) is associated with the presence of prostate cancer and is thus used as an indicator for suspicion of prostate cancer and as a determinant for biopsy. We reviewed a recent retrospective series of 966 consecutive prostate biopsies where F/T PSA was blindly determined and did not influence biopsy indication. We simulated the association of F/T PSA with biopsy outcome and its impact as a biopsy determinant. When adopting an F/T PSA cutoff of 10%, 13%, 16% or 20% among random sextant biopsies in the 4-10 ng/mL total PSA range, the sensitivity was 15%, 37%, 55% and 72% and the specificity 89%, 80%, 64% and 44%, respectively. Using F/T PSA as a biopsy determinant, from 1.7 to 2.6 cancer biopsies would have been delayed to avoid 10 benign biopsies. As this balance is not acceptable, F/T PSA has no role as a biopsy indicator and its clinical use is questionable.

[The stress index: proposed method for risk assessment of stress and burnout in health care settings]

To assess the risk from exposure to stress and burnout in health care workers, a pilot study was planned to compare and integrate the information based on the risk evaluation obtained through different parameters that can be quantified and elaborated to produce a numerical index, called the "Stress Index", and the subjective symptoms from the individual workers. For these purposes, three internationally validated questionnaires were administered: the Job Content Questionnaire, the State-Trait Anxiety Inventory and the Maslach Burnout Inventory. The study considered six different Units from three divisions of Internal Medicine of a large public hospital in Northern Italy, and a total group of 228 health care workers employed in the six units. The results showed an association between the Stress Index scores and the scores from the questionnaires. In particular, in the two units with the highest levels of the index, a significantly higher unbalance between job demand and decision latitude was observed, together with the highest levels of state and trait anxiety and of depersonalization, indicating higher burnout levels.

Blood glutathione as a surrogate marker of cancer tissue glutathione S-transferase activity in non-small cell lung cancer and squamous cell carcinoma of the head and neck

The identification of markers predicting the response to therapy is of the utmost importance in oncology. Several authors have suggested that increased levels of glutathione (GSH) and glutathione S-transferase (GST) activity might be meaningful predictors of poor responsiveness to chemotherapy in several human cancers, but the biological assays have not been standardised and published studies show conflicting evidence. The aim of the present study was to select a validated panel of tests to assess the GST/GSH system in a clinical setting. Matched blood and tissue samples (normal and malignant) from 52 cancer patients with either non-small cell lung cancer (NSCLC) or head and neck squamous cell carcinoma (SCCHN) were investigated. GSH levels and GST activity were higher in cancer tissues than in matched normal tissues in both malignancies. The difference was statistically significant in NSCLC (P=0.0004 and P=0.0002, for GSH and GST, respectively) and borderline in SCCHN (P=0.03 and P=0.02, for GSH and GST, respectively). Moreover a strong correlation was found between the GSH level in whole blood and GST activity in cancer tissue in both malignancies (P=0.003, r=0.53 in NSCLC, P<0.0001, r=0.89 in SCCHN). In conclusion, reliable and robust methods for routine use in tissue extracts and in whole blood have been validated. Our finding regarding the GSH level in blood indicates that circulating GSH could have a clinical relevance as a surrogate marker of GST activity in tumour tissue.

Low molecular weight hyaluronic acid prevents oxygen free radical damage to granulation tissue during wound healing

Hyaluronic acid protects granulation tissue from oxygen free radical damage and stimulates wound healing, but its molecular weight prevents it from permeating the epidermal barrier A low molecular weight hyaluronic acid preparation is able to permeate the skin, but it is unknown whether or not it retains the scavenging effects of oxygen free radicals in granulation tissue. Our experiments were conducted in rats with excisional or incisional wounds. Wound contraction over 11 days and breaking strength on the fifth day were measured. Oxygen free radical production was induced by intraperitoneal administration of two different xenobiotics: phenazine methosulfate and zymosan. The wounds were treated topically with low molecular weight hyaluronic acid (0.2%) cream or placebo. In the incisional wound group, the effects of superoxide dismutase were also determined. Absolute controls received wounds and placebo but no xenobiotics. Wound healing was significantly slower in the xenobiotic group than in the control groups. These effects were strongly reduced by topical administration of low molecular weight hyaluronic acid (0.2%) cream and in incisional wounds by topically injected superoxide dismutase. Low molecular weight hyaluronic acid is effective as the native compound against oxygen free radicals. Its pharmacological effects through transdermal administration should be tested in appropriate models.

Endothelin-1 plasma levels in cluster headache

BACKGROUND AND OBJECTIVE

A role for endothelin-1, a potent vasoconstrictor peptide, in some cerebrovascular diseases has been proposed. To obtain preliminary data about peripheral concentrations of endothelin-1 in acute cluster headache, we measured the plasma endothelin-1 secretory pattern in 10 men with cluster during and independent of a headache attack.

METHODS

We collected blood samples for plasma endothelin-1 determinations at 0, 15, 30, 45, 60, 90, and 120 minutes during a cluster attack and closely monitored blood pressures. We repeated the same sampling during an asymptomatic period.

RESULTS

The mean values of plasma endothelin-1 (before a cluster headache, 3.3 +/- 0.3 pg/mL) significantly increased (F = 2.578, P < .05) during an attack, reaching their peak at 30 minutes (5.0 +/- 0.5 pg/mL, P < .05). We found no significant variations in mean arterial pressure.

CONCLUSION

Endothelin-1 may play a role in the pathophysiology of cluster attacks. The increase in plasma observed during cluster attacks may be linked to alterations in systemic hemodynamics and vascular tone.

Endocrine abnormalities and outcome of ischaemic stroke

Multiple endocrine abnormalities have been reported in stroke patients. In the past few years, it has been claimed that some of these abnormalities may play a role in worsening the neurological deficit and the outcome of stroke. Several mechanisms have been hypothesised, including a direct effect on the development of neuronal cell death, vasospasm, and development of brain edema. In this brief review, we discuss the current knowledge concerning the role of endothelin-1, arginine vasopressin, and cortisol in the pathogenesis of stroke. Finally, we discuss the possibility that leptin, the OB gene product, may be the link of some of these endocrine abnormalities, and that its abnormal secretion during stroke may contribute to the eating disorders and poor nutritional status often seen in these patients.

Twenty-four-hour endothelin-1 secretory pattern in stroke patients

Endothelin-1 (ET-1) is a potent and long-acting vasoconstrictor peptide, which may play a role in the pathophysiology of a number of diseases. Controversial data exist on its role in human ischemic stroke. In order to ascertain whether changes in ET-1 plasma levels occur in ischemic stroke, plasma ET-1 levels and mean arterial pressure were determined in 15 patients at their first ischemic cerebral infarction and in 15 control subjects, over a 24-hour period. In stroke patients, mean 24-hour plasma ET-1 levels (4.9+/-0.5 ng/L) were higher (P< 0.05) than in control subjects (3.2+/-0.3 ng/L), and correlated with the mean size of the lesion, but not with the severity score of the neurological deficit. These results support the hypothesis that ET-1 levels reflect an indicator function for the amount of damaged cerebral tissue rather than a pathophysiological role.

Evaluation of the secretory pattern of plasma arginine vasopressin in stroke patients

Arginine vasopressin (AVP) may play a role in the development of ischemic brain edema and/or cerebral vasospasm. Data available on AVP plasma levels in ischemic stroke are few and discordant. In order to ascertain whether changes in AVP plasma levels occur in ischemic stroke, plasma AVP levels, plasma osmolality and mean arterial pressure were determined in 24 patients with unprecedented ischemic cerebral infarction and in 15 controls over a 24-hour period. In stroke patients, mean 24-hour plasma AVP levels (7.2 +/- 0.8 ng/l) were higher (p < 0.05) than in control subjects (2.4 +/- 0.3 ng/l), and correlated with the severity score of the neurologic deficit and the mean size of the lesion. In patients with a more severe neurologic deficit, the mean 24-hour plasma AVP levels (8.7 +/- 1.0 ng/l) were higher than in patients with a less severe neurologic deficit (5.2 +/- 0.8 ng/l). Data indicate that in ischemic stroke an increased AVP secretion occurs independently of osmotic or baroreceptorial mechanisms. The possibility that AVP may play a role in neuronal cell damage following cerebral ischemia warrants further attention.

Serum leptin levels in patients with viral chronic hepatitis or liver cirrhosis

BACKGROUND/AIM

Serum levels of leptin, the adipocyte-derived hormone regulating food intake and energy expenditure in mammals, have been found to be increased in cirrhotic patients. The aim of the present study was to investigate leptin serum level in relation to anthropometric features and liver function in patients with viral chronic hepatitis or liver cirrhosis.

METHODS

Serum leptin levels were determined by radioimmunoassay in 30 male and 10 female patients with chronic hepatitis, in 42 male and 10 female patients with liver cirrhosis, and in four respective control groups. Liver function was evaluated by the monoethylglycinexylidide formation test. Body mass index and body fat mass were estimated by weight, height and skinfold thickness measurements.

RESULTS

Compared with controls, absolute serum leptin levels were significantly (p<0.01) lower in chronic hepatitis patients and similar in cirrhotic patients. Leptin serum levels were significantly (p<0.05) higher in cirrhotic than in chronic hepatitis patients. When expressed in relation to body fat mass, the above differences persisted; however, cirrhotic females showed significantly (p<0.05) higher serum leptin values than controls. Serum leptin values correlated negatively (p<0.01) with monoethylglycinexylidide serum values in all groups of patients.

CONCLUSIONS

In patients with chronic viral liver disease, serum leptin levels tend to increase as liver function worsens. This may reflect a decline in the ability to downregulate energy expenditure as an adaptation to anorexia and/or to defective substrate utilisation due to liver disease and may negatively influence body weight homeostasis in these patients.

An alternative approach to the preparation of (188)Re radiopharmaceuticals from generator-produced [(188)ReO(4)](-): efficient synthesis of (188)Re(V)-meso-2,3-dimercaptosuccinic acid

A new efficient approach for the preparation of (188)Re radiopharmaceuticals starting from [(188)ReO(4)](-), produced at a carrier-free level through the (188)W/(188)Re generator system, is described. The reaction procedure was based on the combined action of different reagents and has been applied in detail to the preparation of the therapeutic agent (188)Re(V)-DMSA (H(2)DMSA [meso-2,3-dimercaptosuccinic acid]). The most efficient combination required the use of SnCl(2), oxalate ions, and gamma-cyclodextrin. These were reacted with [(188)ReO(4)](-) and H(2)DMSA to afford the final radiopharmaceutical in high radiochemical purity, at room temperature, and in weakly acidic solution. The role played by the various reagents in the reaction was investigated. It was found that SnCl(2) behaved as the actual reducing agent, whereas oxalate and gamma-cyclodextrin greatly enhanced the ease of reduction of [(188)ReO(4)](-) through the action of two hypothetical mechanisms. In the first step of the reaction, oxalate ions gave rise to the formation of Re(VII) complexes with the concomitant expansion of the coordination sphere of the metal. This process strongly favored the electron transfer between Sn(2+) and Re(+7) centers, giving rise to intermediate reduced rhenium complexes. These species were further stabilized by the formation of transient host-guest aggregates with gamma-cyclodextrin and finally converted into (188)Re(V)-DMSA through simple replacement of the coordinated ligands by H(2)DMSA.

Structural basis for SH2D1A mutations in X-linked lymphoproliferative disease

X-linked lymphoproliferative disease (XLP) is a rare and severe immune deficiency, characterized by abnormal immune responses to the Epstein-Barr virus. Recently, the gene responsible for XLP, SH2D1A, has been identified and shown to code for a small cytoplasmic protein with an SH2 domain that interacts with SLAM and 2B4, two receptorial molecules involved in signal transduction in T and NK cells, respectively. A variety of SH2D1A gene mutations have been reported thus far in XLP males. Here we describe a single-strand conformation polymorphism assay for mutation analysis in XLP. Four novel patients with SH2D1A mutations are described. These mutants, and the others previously reported in the literature, have been included in a Registry (SH2D1Abase) that is fully accessible on the World Wide Web. A three-dimensional model of the SH2 domain of the SH2D1A protein has been developed, based on homology with other SH2 domains. The structural consequences of disease-causing SH2D1A mutations are discussed.

Relationship between myocardial 123I-metaiodobenzylguanidine scintigraphic uptake and heart rate variability in patients with syndrome X

BACKGROUND

We have recently demonstrated a striking impairment in cardiac uptake of 123I-metaiodobenzylguanidine (MIBG) in most patients with syndrome X. In this study we investigated the relationship between cardiac MIBG defects and cardiac autonomic activity in these patients.

METHODS

MIBG myocardial scintigraphy and time-domain and frequency-domain heart rate variability (HRV) were compared in 11 syndrome X patients and 10 healthy controls. Cardiac MIBG uptake was assessed by the heart/mediastinum ratio and a cardiac MIBG uptake defect score (higher values = lower uptake).

RESULTS

The heart/mediastinum ratio was lower (1.71 +/- 0.6 vs 2.19 +/- 0.3, p = 0.03) and MIBG uptake score higher (37.1 +/- 32 vs 4.0 +/- 2.5, p = 0.005) in syndrome X patients, whereas average HRV values did not differ between the two groups. However, while there were no correlations between MIBG uptake and HRV in controls, in syndrome X patients both the heart/mediastinum ratio and MIBG uptake score correlated significantly with two HRV parameters, specific for vagal activity: the square root of the mean squared differences of consecutive RR intervals (r = 0.73, p = 0.01, and r = -0.67, p = 0.02, respectively), and high frequency (r = 0.64, p = 0.03, and r = -0.74, p = 0.009, respectively). CONCLUSIONS; In patients with syndrome X, the impairment in cardiac MIBG uptake was associated with a reduction in HRV indexes mainly reflecting vagal modulation of sinus node, thus suggesting that a predominance of cardiac adrenergic activity may be present in those with abnormal cardiac MIBG scintigraphy.

Twenty-four-hour variation in serum leptin in the elderly

To investigate the possibility that the aging process may affect the diurnal variation in serum leptin in humans, serum leptin levels were measured by a sensitive radioimmunoassay method in 12 elderly (aged 72 to 87 years) and 10 middle-aged (35 to 50 years) lean male subjects. Fasting blood samples (4 mL) were drawn at 8:00 AM, and then every 4 hours until 10:00 PM and every 2 hours from 12:00 midnight to 8:00 AM of the next morning. Circadian rhythmicity analysis was performed using the cosinor method. In elderly subjects, serum leptin levels showed a significant diurnal rhythm, which was similar to that observed in controls. Single cosinor analysis showed a significant rhythm in eight of 12 elderly subjects and in all middle-aged subjects but one. Compared with middle-aged subjects, similar mesor mean values (7.8 +/- 1.0 v 8.1 +/- 0.8 ng/mL) but a decreased amplitude (1.4 +/- 0.3 v 2.3 +/- 0.2 ng/mL) and an earlier acrophase (11:56 PM v 2:04 AM) were observed in the elderly. The data demonstrate that the diurnal variation in serum leptin is generally preserved in the elderly. However, the amplitude of leptin diurnal excursion undergoes a reduction with advancing age. It can be speculated that the blunted diurnal variation in serum leptin observed in the elderly may result in an alteration of the afferent signal in the adipose tissue-central nervous system homeostatic loop.

Somatostatin release in response to glucose is impaired in chronic renal failure

In order to evaluate somatostatin (SRIH) secretion in uremia, plasma SRIH concentrations were determined in basal conditions and after an oral glucose tolerance test (OGTT) in 14 non-dialysed patients with chronic renal failure (CRF), seven of whom had normal glucose tolerance (NGT) and seven impaired glucose tolerance (IGT). Plasma insulin, C-peptide and glucagon and blood glucose concentrations were also evaluated. The results were compared with those obtained in a group of age- and sex-matched normal subjects. In CRF patients, plasma SRIH fasting values (8.6 +/- 0.6 and 7.8 +/- 0.6 pmol/L in NGT and IGT patients, respectively) were comparable to those recorded in controls (7.7 +/- 0.5 pmol/L). SRIH response to OGTT, evaluated as area under curves (AUC) above basal, was similar in both groups of CRF patients (412.9 +/- 84.5 and 415.6 +/- 51.9 pmol/L per min), and significantly lower than in controls (660.1 +/- 58.5 pmol/L per min). Data indicate that chronic uremia induces a loss of SRIH secretory cell responsiveness to glucose. A possible effect of impaired SRIH secretion on glucose metabolism in CRF is discussed.

Inter-organ leptin exchange in humans

To assess the individual role of splanchnic organs, kidney, and peripheral tissues on leptin metabolism, leptin exchange across the splanchnic bed, kidney, and leg has been evaluated by the arterio-venous technique in post-absorptive non-obese subjects. Leptin levels in the hepatic and renal veins were significantly lower (p < 0.001), while femoral vein levels were consistently greater (p < 0.05) than in the artery. The fractional extraction of leptin, namely the percentage of arterial leptin extracted, was greater in splanchnic organs (16%) than in the kidney (9.5%). Urinary excretion of leptin was undetectable in most subjects, indicating that leptin is degraded within the kidney. There was no correlation between fractional extraction of leptin and glomerular filtration rate, whereas leptin fractional extraction was directly related to renal plasma flow (p = 0.017). Renal leptin clearance was about 50% of the glomerular filtration rate. Our data demonstrate that both splanchnic organs and the kidney cooperate in the disposal of leptin, while peripheral tissues add significant amounts of leptin to the circulation. In non-obese subjects the contribution of the kidney to whole body clearance is no more than 50%. The removal of leptin by the kidney depends on renal plasma flow but not on glomerular filtration rate or filtered leptin.

Intraindividual comparison of 99mTc-labelled anti-SSEA-1 antigranulocyte antibody and 99mTc-HMPAO labelled white blood cells for the imaging of infection

Technetium-99m labelled antigranulocyte antibodies are ready to use and are sensitive and specific in the diagnosis of infectious diseases. 99mTc-SSEA antigranulocyte antibodies have a very high affinity constant (Kd 10(-12) M) for human neutrophils (PMNs), and excellent imaging qualities with high target/background ratios. The aim of this study was to compare the diagnostic accuracy of the 99mTc-anti-SSEA-1 monoclonal antibody (Mab) with that of 99mTc-hexamethylpropylene amine oxime (HMPAO)-labelled white blood cells (WBCs). To this end, 17 patients with 23 proven infectious foci were examined with 555 MBq 99mTc-anti-SSEA-1 MAb and with 370 MBq 99mTc-HMPAO labelled autologous leucocytes within a period of 7 days. All the infections were confirmed by culture, biopsy, surgery and follow-up. Whole-body images and planar spot views with the antibody were performed at 1-h, 4-h and 24-h post injection; the biodistribution of the antibody was quantified, absorbed radiation doses were calculated and the diagnostic results were compared with the 99mTc-HMPAO WBC images. Human anti-mouse antibody (HAMA) evaluation was performed in all patients before and 3 months after antibody injection. Blood was drawn at different times after 99mTc-anti-SSEA-1 MAb injection to determine the amount of granulocyte-associated radioactivity and to calculate recovery. 99mTc-anti-SSEA-1 MAb scintigraphy detected all 23 lesions, while 21 were detected with 99mTc-HMPAO WBC scan. In this small group of patients, the sensitivity and specificity of 99mTc-anti-SSEA-1 MAb scintigraphy were 95% and 96% respectively, as compared with 91% and 82% respectively for 99mTc-HMPAO WBC scan. An increasing uptake of the injected activity in the lesion at different time points was indicative of high affinity and of specific PMN binding. There was no HAMA formation. In four of five patients investigated, a transient mild leukopenia was found at 15 min p.i.. There was increased uptake of the antibody in liver and spleen and normal uptake in kidneys and bone marrow. The estimated radiation doses for the whole body and the red bone marrow were 1.1x10(-2) cGy/37 MBq and 5.3x10(-2) cGy/37 MBq, respectively. The activity associated to the PMNs in vivo was 33.5%, 30.6%, 21.3% and 9% at 5, 15, 30 and 45 min. post-injection, respectively. It is councluded that use of 99mTc-anti-SSEA-1 antigranulocyte antibodies demonstrates promising results comparable to those obtained with 99mTc-labelled autologous WBCs. The 99mTc-labelled MAb is ready to use, has excellent image qualities and a high target/background ratio.

Plasma somatostatin response to an oral test meal in liver transplant patients

Ten liver transplant patients were studied in basal conditions and after ingestion of a standard mixed test meal. Control groups included 10 normal subjects, 10 patients with nonalcoholic liver cirrhosis, and seven kidney transplant patients. Plasma somatostatin, blood glucose, and plasma insulin, C-peptide, and glucagon were determined before and 15, 30, 45, 60, 90, 120, and 180 minutes after the start of the meal. In liver transplant patients, basal somatostatin and insulin levels were significantly lower than in cirrhotics and were comparable to those recorded in controls and in kidney transplant patients. The time course of the somatostatin secretory response after the meal was similar in any group, but the increase, evaluated as the incremental area above baseline, was significantly higher in liver transplant patients than in controls and cirrhotics and comparable to that recorded in kidney transplant patients. Insulin incremental areas were also lower than in cirrhotics and comparable to those recorded in controls and kidney transplant patients. The data suggest that in liver transplant patients an increased somatostatin response to a meal may be related to a relative beta-cell secretory defect, which in turn seems consequent to immunosuppressive treatment.

Abnormal cardiac adrenergic nerve function in patients with syndrome X detected by [123I]metaiodobenzylguanidine myocardial scintigraphy

BACKGROUND

Previous studies have suggested that an abnormal cardiac adrenergic tone may have a pathophysiological role in syndrome X (effort angina, positive exercise testing, angiographically normal coronary arteries).

METHODS AND RESULTS

To evaluate cardiac adrenergic nerve function, we performed [123I]metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 12 patients with syndrome X and 10 control subjects. Cardiac MIBG uptake was assessed by the heart/mediastinum (H/M) ratio and by an MIBG uptake defect score (higher values=lower uptake). In syndrome X patients, we also correlated MIBG scintigraphic findings with stress myocardial perfusion as assessed by 201Tl scintigraphy. An inferior MIBG defect was observed in only 1 control subject, whereas 9 patients (P<.01) showed MIBG defects. The heart was totally or almost totally invisible on MIBG images in 5 patients, and predominantly regional defects were observed in 4. The H/M ratio was lower (1.70+/-0.6 versus 2.2+/-0.3, P=.03) and MIBG uptake defect score higher (35+/-31 versus 4+/-2, P=.003) in syndrome X patients. Reversible stress thallium perfusion defects were found in 62% of patients with MIBG defects but in no patient with normal MIBG uptake. MIBG defects persisted unchanged in 7 patients at a 5+/-3-month follow-up study.

CONCLUSIONS

In this study, obvious defects in global and/or regional cardiac MIBG uptake, indicating an abnormal cardiac adrenergic nerve function, were detected in 75% of patients with syndrome X. These findings strongly support the cardiac origin of chest pain in syndrome X, although the mechanisms and the pathophysiological meaning of the abnormal cardiac MIBG uptake in these patients deserve further investigation.

Potential use of iodine-123 metaiodobenzylguanidine radioaerosol as a marker of pulmonary neuroadrenergic function

Iodine-123 metaiodobenzylguanidine (123I-MIBG) radioaerosol is of potential use in the investigation of the neuroadrenergic function of the lungs; however, before the method can be successfully employed the following issues need to be clarified: (1) Does the nebulization affect the radiochemical purity of 123I-MIBG? (2) Is the pulmonary distribution of inhaled 123I-MIBG homogeneous in normal subjects? (3) Does the pulmonary clearance of inhaled 123I-MIBG reflect the functional status of the neuroadrenergic system of the lungs? In this study we performed: (1) a chromatographic study of nebulized 123I-MIBG; (2) a quantitative evaluation of the lung distribution of 123I-MIBG radioaerosol in normal subjects as compared with that of technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) and (3) an assessment of 123I-MIBG lung clearance both under control conditions and after pharmacologically induced beta-blockade, again compared with 99mTc-DTPA. For these purposes, eight normal subjects were divided randomly into an "MIBG group" and a "DTPA group" (four subjects each) and submitted to three scintigraphic studies each: a baseline study, and studies after the administration of a low (80 mg) and a high (160 mg) dose of propranolol. Radiochemical purity of nebulized 123I-MIBG ranged between 97.18% and 98.70%. The lung distribution of 123I-MIBG, as judged by the aerosol penetration index, was identical to that of 99mTc-DTPA under all study conditions. The 123I-MIBG clearance rate was slower than that of 99mTc-DTPA under baseline conditions (135+/-32 min vs 69+/-27 min, P<0.01) and increased significantly after propranolol administrations, while the 99mTc-DTPA clearance did not change. The following conclusions were drawn: (1) the nebulization does not affect the radiochemical purity of 123I-MIBG; (2) the lung distribution of 123I-MIBG is homogeneous in normal subjects; (3) the pulmonary clearance of 123I-MIBG reflects the functional status of the neuroadrenergic system of the lungs. Thus this scintigraphic method is suitable for research and perhaps for future clinical use.

A human neuroblastoma xenograft model for 125-I-metaiodobenzylguanidine biodistribution studies

We developed an animal model to evaluate the 125-I-metaiodobenzylguanidine (125-I-mIBG) biodistribution in tumor bearing mice. Six weeks old nude-atimic mice were subcutaneously injected with 30 x 10(6) cells of the human neuroblastoma (NB) cell line SH-SY5Y. TE-671, a rhabdomyosarcoma cell line, was used as a control tumor without a specific mIBG uptake mechanism. In order to prevent possible tumor rejection mediated by NK activity the anti asialo GM1 antiserum was administered intraperitoneally once a week for 4 weeks. The maximum anti asialo mediated effect was obtained by administering the first dose the same day as the cell implant. In this group of animals by 9 weeks 98% of mice had a measurable tumor. We have utilized this model to evaluate the biodistribution of 125-I-mIBG given as two different formulations: standard preparation with a specific activity of 84 mCi/mg and the no carrier added (n.c.a) formulation with a specific activity of approximately 8,000 mCi/mg. Our preliminary results indicate that the biodistribution of the two different formulations in the various organs are similar. Therefore it appears that n.c.a. mIBG should not cause an increased toxicity in possible normal target organs such as heart or adrenals. Additional experiments will be performed in this model to ascertain if there is a potential advantage of the clinical use of n.c.a. mIBG over the standard preparation.

Liposome-delivered 131I-labelled Zn(II)-phthalocyanine as a radiodiagnostic agent for tumours

131I-Zn(II)-phthalocyanine (ZnPc) incorporated into unilamellar liposomes has been systemically injected to mice bearing a transplanted MS-2 fibrosarcoma. Biodistribution studies show that the pharmacokinetic behaviour of 131I-ZnPc is very similar to that defined for the parent molecule ZnPc including a serum half-life of ca. 12 h, a high recovery from liver and spleen and minimal accumulation in kidney and brain. The most important pharmacokinetic parameter is represented by the high tumour/ muscle ratio of 131I-ZnPc concentration (ca. 9 at 24 h post-injection). These results suggest the possible use of the radiolabelled derivative for a real-time non-invasive monitoring of the ZnPc concentration in the tumour and peritumoural tissue during photodynamic therapy.

Crohn's-like colitis in glycogen storage disease Ib: a case report

Association between glycogen storage disease type Ib and Crohn's like disease is rare. We present one such case. A young woman with glycogen storage disease type Ib underwent a right hemicolectomy for stenosis and a blind fistulous tract. The histological picture of the resected bowel was consistent with the diagnosis of Crohn's like disease. A leak in the entero-colostomy occurred during medical treatment with steroids, sulfasalazine, and methronidazole. Partial ileal and colonic resection and a new anastomosis were then performed. Recombinant human colony-stimulating factor (300 mcg/die subcutaneously) was then started. The neutrophils promptly increased to a normal range, and the neutrophil function tests improved. The postoperative course was uneventful and the patient did not have a relapse of the bowel disease.

Evaluation of beta-endorphin secretion in patients suffering from episodic cluster headache

In order to obtain data regarding peripheral levels of beta-endorphin in head pain syndromes, we evaluated the plasma beta-endorphin secretory pattern in 12 adult male patients suffering from cluster headache. Blood samples were drawn every 2 hours for a 24-hour period, and in addition at 30-minute intervals for 120 minutes during cluster attacks. The same sampling was repeated during an asymptomatic period. Cluster headache patients showed no significant beta-endorphin circadian rhythm and a delayed acrophase during cluster periods compared with that recorded in the remission period and in normal subjects. Eighteen cluster headache attacks were recorded during the study day, 13 (72%) of which were followed by a significant increase in beta-endorphin levels. No correlation was found between beta-endorphin maximum net increase and intensity and/or duration of pain. These data suggest the hypothesis of a temporary alteration of beta-endorphin circadian secretion, probably related to involvement of neural structures controlling biorhythm pacemakers.

Effect of the 5-HT3 receptor antagonist ondansetron on plasma AVP secretion: a study in cancer patients

The aim of the present study was to investigate the effects of a serotonin subtype 3 receptor antagonist, ondansetron, on arginine vasopressin secretion in humans. Plasma vasopressin concentrations were determined in 24 breast cancer patients undergoing adjuvant chemotherapy, before and after ondansetron intravenous (i.v.) administration. Ondansetron (8 mg i.v. at time 0 and 8 mg po at time 240 min) was administered alone in 12 patients and afterwards in combination with chemotherapy in all patients. No changes in hormone levels were found after ondansetron alone and in 17 patients who did not claim nausea and/or emesis after chemotherapy. In seven patients who experienced nausea and /or emesis, vasopressin levels significantly (P < 0.01) increased (from 6.3 +/- 0.9 ng/L in basal conditions to 15.1 +/- 3.3 ng/L at 10 h; P < 0.05 vs baseline). The results suggest the possibility that in humans, serotoninergic mechanisms, which modulate vasopressin secretion, may involve the activation of the serotonin receptors recognised by ondansetron.

In vitro and in vivo studies with no-carrier added radioiodinated MIBG

An important drawback of radioiodinated MIBG prepared by isotopic exchange (maximum specific activity: 100 Ci/mmol) is that a considerable amount of carrier is present in the "ready to use" radiopharmaceutical, thus affecting MIBG uptake in the target cells. To improve the therapeutic utility of MIBG an interesting method was developed for the no-carrier-added (n.c.a.) radioiodination of MIBG via a halodesilylation reaction using 3-trimethylsilybenzylguanidine (TMSBG) as precursor. In order to investigate its possible clinical usefulness, n.c.a. [125I]- and [131I]MIBG was prepared according this procedure. HPLC analysis of the labeling mixture showed that the labeling yield reached values greater than 98% within 20 minutes at 70 degrees C. HPLC fraction containing [131I]MIBG was then recovered and tetrahydrofurane was removed under nitrogen stream. Biodistribution studies were performed in BALB/c normal mice and compared with those obtained using [131I]MIBG prepared by isotopic exchange. Preliminary results showed that at 4 hours myocardial uptake was significantly higher than that of c.a. MIBG (20.3 +/- 0.4 %ID/g). Adrenal uptake gradually increased over time; at 24 hours adrenal uptake was almost twofold that a 1 hour. MIBG uptake was also studied in the human neuroblastoma cell line SH-SY5Y which has a specific uptake system for MIBG. The kinetic parameters for MIBG in this line are: km = 0.27 +/- 0.03 microM, Vmax = 39.5 + 1.8 pmol/10(6) cell/10 min. Preliminary data from in vitro binding studies showed that significantly higher levels of specifically incorporated radioactivity can be achieved using n.c.a. [125I]MIBG instead of c.a. [125I]MIBG.

Use of metaiodobenzylguanidine (MIBG) in pneumology

Norepinephrine (NE) is one of the many biologically active substances that are metabolized by the lung. The norepinephrine uptake in the lung has been widely investigated in animal studies in order to detect abnormalities of the endothelial cells. 131I- or 123I-labelled metaiodobenzylguanidine (MIBG) is a radioactive tracer that shares several metabolic pathways with NE; it has been used instead NE or both in animal and in human studies for the same purposes. It has been definitely demonstrated that MIBG lung uptake following intravenous administration is a reliable marker of minimal endothelial cell lesions and it allows one to investigate several conditions involving damage to the lung vasculature such as adult respiratory distress syndrome, post-actinic lung fibrosis or chemotherapic lung toxicity. MIBG could also potentially be used as a tracer of the neuroadrenergic system of the airways, once it has been deposited in the whole branches of the bronchial tree. With this in mind we evaluated the feasibility of the administration of MIBG in radioaerosol form. We first performed a chromatographic study on [123I]MIBG aliquots aerosolized for variable lengths of time (2-30 minutes). Radiochemical purity was always over 96%, thus demonstrating that aerosolization does not significantly modify the stability of the tracer. We then compared both the lung clearance curves and the scintigraphic images in two groups of normal subjects who respectively underwent [123I]MIBG and 99mTc-DTPA radioaerosol dynamic scintigraphy. We found that MIBG clearance to be significantly lower than that of DTPA (135 +/- 32 minutes versus 69 +/- 27 minutes, p < 0.01), probably due to its being trapped in the adrenergic nerve endings of the airways. The pulmonary distribution of both tracers was homogeneous, as demonstrated by the correspondence of the values for the aerosol penetration index in both groups of subjects. Such results warrant further research and pharmacologic tests.