Microbial composition associated with biliary stents in patients undergoing pancreatic resection for cancer

Malignant bile duct obstruction is typically treated by biliary stenting, which however increases the risk of bacterial infections. Here, we analyzed the microbial content of the biliary stents from 56 patients finding widespread microbial colonization. Seventeen of 36 prevalent stent species are common oral microbiome members, associate with disease conditions when present in the gut, and include dozens of biofilm- and antimicrobial resistance-related genes. This work provides an overview of the microbial communities populating the stents.

Clinical usefulness of routinely performed drain fluid cultures after pancreaticoduodenectomy. A new ally to predict patients' outcomes?

BACKGROUND

Previous studies showed that bacterial contamination of surgical drains was associated with higher morbidity and mortality following pancreaticoduodenectomy (PD). However, there is still no agreement on the routine use of fluid drainage cultures in the management of patients underwent PD. Therefore, we aimed to clarify the role of surgical drain bacterial contamination in predicting patients' postoperative course.

METHOD

Single-centre study including patients underwent PD at Humanitas Research Hospital (2010-2021). Preoperative, intraoperative and postoperative data were collected. Routinely performed fluid drain cultures on postoperative day (POD) 5 were analyzed and compared among patients throughout the cohort.

RESULTS

A total of 825 patients were analyzed. Bacterial contamination of surgical drains was observed in 420 (50.9 %) patients and it was found to be associated with a higher rate of B/C grade pancreatic fistula (POPF) (P < 0.001), Clavien-Dindo≥3 (P < 0.001), 30-day mortality (P = 0.011), wound infection (P < 0.001), relaparotomies (P = 0.003) and greater length of hospital stay (LOS) (P < 0.001). Also, E. coli surgical drain contamination was demonstrated to double the risk of B/C grade POPF development (OR = 1.628, 95 % IC = 1.009-2.625, P = 0.046). Finally, preoperative biliary drainage (OR = 2.474, 95 % IC = 1.855-3.298, P < 0.001), age ≥75 years old (OR = 1.492, 95 % IC = 1.077-2.067, P = 0.016) and isolated Roux-en-Y pancreaticojejunostomy (OR = 1.639, 95 % IC = 1.229-2.188, P < 0.001) were identified as risk factors for surgical drains bacterial contamination.

CONCLUSION

Bacterial contamination of surgical drains predicts the development of B/C grade POPF and other major complications after PD. Therefore, we suggest the routine use of fluid drain cultures following PD.

Conjunctivitis as a sign of persistent SARS-COV-2 infection? An observational study and report of late symptoms

PURPOSE

To investigate if symptomatic conjunctivitis during the recovery phase of the disease could be associated to a persistent presence of SARS-CoV-2 in the upper respiratory tract. Secondary end points were to analyze the presence of SARS-CoV-2 in the conjunctiva of ocular symptomatic patients and to record the presence of ocular disturbances at this point of the disease.

METHODS

An observational study including consecutive COVID19 patients treated at Humanitas Clinical and Research Hospital who were attending for nasopharyngeal swab to confirm the resolution of SARS-CoV-2 infection and end of isolation. We examined 129 consecutive patients from May to June 2020. The primary end point was to determine if symptomatic conjunctivitis at this point of the disease could be associated to a persistent presence of SARS-CoV-2 in the upper respiratory tract. Secondary end points were to analyze the presence of SARS-CoV-2 in the conjunctiva of ocular symptomatic patients and to record the presence of ocular disturbances at this point of the disease.

RESULTS

One hundred twenty eight patients were included, 9.38% had conjunctivitis, none resulted positive to conjunctival PCR swab test, while two of them had positive nasopharyngeal result. Mean time elapsed since the first COVID-19 positive swab to the time of examination was 6 weeks (  ± 3). The only significant association was the presence of conjunctivitis with older age (65.3  ±  12.7 vs 56.7  +  13.5. p  =  0.046). Nasopharyngeal swab resulted positive in 22 patients (17.19%). While 88 patients (68.2%) did not have any ocular complain during their COVID19 disease. The 40 patients (31.8%) reporting ocular disturbances complained about: redness (25.43%), tearing (19.53%), burning (18.35%), foreign body sensation (17.18%), itching (15.62%), and discharge (12.5%).

CONCLUSION

This study showed that late conjunctivitis cannot be considered as a marker of persistent infection when patients are sent to confirm the resolution of SARS-CoV-2 infection.

Chest CT in patients with a moderate or high pretest probability of COVID-19 and negative swab

Objectives

We aimed to assess the diagnostic performance of CT in patients with a negative first RT-PCR testing and to identify typical features of COVID-19 pneumonia that can guide diagnosis in this case.

Methods

Patients suspected of COVID-19 with a negative first RT-PCR testing were retrospectively revalued after undergoing CT.

CT was reviewed by two radiologists and classified as suspected COVID-19 pneumonia, non-COVID-19 pneumonia or negative.

The performance of both first RT-PCR result and CT was evaluated by using sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) and by using the second RT-PCR test as the reference standard.

CT findings for confirmed COVID-19 positive or negative were compared by using the Pearson chi-squared test (P values < 0.05)

Results

Totally, 337 patients suspected of COVID-19 underwent CT and nasopharyngeal swabs in March 2020. Eighty-seven out of 337 patients had a negative first RT-PCR result; of these, 68 repeated RT-PCR testing and were included in the study.

The first RT-PCR test showed SE 0, SP = 100%, PPV = NaN, NPV = 70%, AUC = 50%, and CT showed SE = 70% SP = 79%, PPV = 86%, NPV = 76%, AUC = 75%.

The most relevant CT variables were ground glass opacity more than 50% and peripheral and/or perihilar distribution.

Discussion

Negative RT-PCR test but positive CT features should be highly suggestive of COVID-19 in a cluster or community transmission scenarios, and the second RT-PCR test should be promptly requested to confirm the final diagnosis.

Caspofungin for primary antifungal prophylaxis after T-cell-replete haploidentical stem cell transplantation with post-transplant cyclophosphamide

Objectives

T‐cell–replete haploidentical stem cell transplantation (Haplo‐SCT) with post‐transplant cyclophosphamide (PT‐Cy) is at high risk of invasive fungal infections (IFI), and anti‐mold–active drug is required for primary antifungal prophylaxis (PAP) according to international guidelines. No data are available on the efficacy of caspofungin as PAP in this setting.

Methods

Here, we report our retrospective experience with 103 consecutive patients treated with caspofungin as PAP after Haplo‐SCT. Caspofungin was administered only during the pre‐engraftment phase.

Results

Hundred‐day cumulative incidence of proven‐probable IFI (PP‐IFI) was 8.7% and median day of onset was 19 post‐SCT. No patient died of PP‐IFI, and overall survival (OS) and non‐relapse mortality (NRM) hazard ratio (HR) for patients experiencing IFI were 1.02 (P = 0.9) and 0.7 (P = 0.7), respectively. Three‐year overall survival (OS) and 1‐year non‐relapse mortality (NRM) were 55% and 19%, respectively. By univariate analysis, duration of neutropenic phase and partial remission pre‐transplant disease status were associated with increased incidence of IFI, but were not confirmed by multivariate analysis.

Conclusion

In summary, PAP with caspofungin is an effective strategy for preventing IFI in the context of Haplo‐SCT with PT‐Cy. Further efforts are required in order to identify more potent strategies able to avoid the occurrence of breakthrough infections.

Efficacy of intraventricular amikacin treatment in pan-resistant Pseudomonas aeruginosa postsurgical meningitis

Background

We describe a case of pan-resistant Pseudomonas aeruginosa postsurgical meningitis associated with the presence of an external ventricular device. We changed therapy twice; finally, by using amikacin and a continuous infusion of cefepime, we obtained clinical improvement.

Case presentation

A female patient, who underwent surgery for a cavernous angioma, presented with meningitis. Cerebrospinal fluid culture revealed a multidrug-resistant Pseudomonas aeruginosa, initially sensitive only to colistin. We successfully used intrathecal amikacin and intravenous cefepime continuous infusion plus intravenous amikacin after two previous ineffective therapeutic approaches.

Conclusion

The evaluation of the antibiotic concentration and the bactericidal activity in cerebrospinal fluid may contribute to the choice of the drug in cases of multidrug-resistant meningitis.

A reduced dose of fluconazole as primary antifungal prophylaxis is not associated with increased risk of invasive fungal infections after allogeneic stem cell transplantation from a HLA identical sibling

BACKGROUND

Invasive fungal infections (IFI) represent a common side effect of allogeneic hematopoietic stem cell transplant (allo-SCT), resulting in increased non relapse mortality (NRM) and reduced overall survival (OS) rates. Seventy-five days of Fluconazole 400 mg/d represents the standard primary antifungal prophylaxis (PAP) after allo-SCT, especially for low-risk transplants. However, the ideal dosage of fluconazole has never been tested.

METHODS

Here, we report the experience of our institution on 113 consecutive patients receiving an allo-SCT from a HLA identical sibling between 1999 and 2015, where PAP consisted of fluconazole 100 mg/d only during the pre-engraftment phase. At the time of transplant, all patients were considered at low-risk for mold infection according to ECIL-5 guidelines.

RESULTS

Cumulative incidence of possible-probable-proven IFI was 11.7%, while proven-probable (PP-IFI) occurred in 5.5% of patients by day 100 post transplant. Of note, only 1 patient developed invasive Candidiasis due to a non-albicans strain and stool-screening tests were negative for colonization by Candida albicans species. The incidence of 1-year acute and 2-year chronic graft-versus-host-disease (GVHD) was 30% and 45%, respectively. Three-year OS and 1-year NRM were 53% and 11.3%, respectively.

CONCLUSION

In summary, fungal prophylaxis with fluconazole 100 mg/d results in very low incidence of PP-IFI, GVHD and NRM in low-risk allo-SCT.

Reducing rates of Clostridium difficile infection by switching to a stand-alone NAAT with clear sampling criteria

Background

Clostridium difficile infection is an important cause of morbidity and mortality but the optimal method of diagnosis for both patient management and infection prevention remains controversial.

Methods

Our hospital made a decision to switch from the use of toxin immunoassay to a stand-alone nucleic acid test. This change was accompanied by the provision of clear sampling guidance and rejection criteria and this study aimed to assess the impact of that change. We analysed sample numbers, numbers of positive results, and the proportion of cases assessed as healthcare acquired over a 6-year period during which the testing method was changed from a toxin A/B immunoassay to a stand-alone commercial nucleic acid test after the first two years.

Results

Sample numbers and numbers of cases assessed as healthcare acquired fell following the introduction of the nucleic acid test and sampling guidance, while infection rates in other hospitals in the same region remained relatively stable.

Conclusions

It is our opinion that the use of a highly sensitive assay together with clear sampling guidance offers the optimal approach to patient management and best use of isolation facilities.

Multicenter prospective study on the prevalence of colistin resistance in Escherichia coli: relevance of mcr-1-positive clinical isolates in Lombardy, Northern Italy

Background

The emergence of the plasmid-mediated colistin resistance mechanism in Escherichia coli has raised concern among public health experts as colistin is a last-line antimicrobial resort. The primary aim of the study was to investigate the prevalence of this resistance trait in E. coli isolates circulating in the Lombardy region, Northern Italy. The presence of mcr-type genes and their genetic relationship were also studied.

Materials and methods

A prospective study was performed during a 4-month period (May to August, 2016) in six acute care Hospitals. Consecutive nonduplicate clinical isolates of E. coli from any type of clinical specimen, with the exception of rectal swabs, were included in the study. Isolates that exhibited MIC values for colistin >2 mg/L were further investigated. Bacterial identification was obtained by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Amplification of mcr-type genes (−1 to −5 variants) and microarray analysis were accomplished. Repetitive sequence-based PCR (Rep-PCR) and multilocus sequence typing (MLST) analysis were used for genotyping.

Results

Overall, 3,902 consecutive E. coli isolates (2,342 from outpatients, 1,560 from inpatients) were evaluated during the study period. Of them, 18/3,902 (0.5%), collected from 4/6 centers, showed resistance to colistin. These isolates were mostly obtained from urine of both outpatients (n=12) and inpatients (n=6). Colistin MIC values ranged from 4 to 8 mg/L. The mcr-1 gene was detected in 10/18 isolates (7 from outpatients, 3 from inpatients). Rep-PCR and MLST analysis revealed the presence of nine different clusters. Further mcr-type genes were not detected.

Conclusion

Resistance to colistin in E. coli clinical isolates appears low in our geographic area. With regard to mcr-1-positive isolates, they accounted for approximately 50% of colistin-resistant E. coli isolates, thus representing a relevant resistance mechanism in this context. Although overall limited, the presence of mcr-1 determinant in our region should not be ignored and great concern should be given to the continuous surveillance.

Helicobacter pylori Bacteremia: An Unusual Finding

We report a case of Helicobacter pylori transient bacteremia in a woman with ulcerated antral gastric cancer. The patient was hospitalized for laparoscopy and subtotal gastrectomy. After surgery she developed fever (39°C) and was empirically treated with levofloxacin. Blood cultures, collected and sent immediately to Laboratory, were positive for a spiral Gramnegative bacterium. This isolate was identified as H. pylori and the specific susceptibility test was performed. One day after the fever was decreased but antibiotic treatment with levofloxacin was continued and it was maintained until discharge. In summary, H. pylori transient bacteremia may occur as a rare complication after stomach surgery. Further studies are necessary to elucidate the potential role of H. pylori presence in blood.

Role of preoperative biliary stents, bile contamination and antibiotic prophylaxis in surgical site infections after pancreaticoduodenectomy

BACKGROUND

The routine use of preoperative biliary drainage before pancreaticoduodenectomy (PD) remains controversial. This observational retrospective study compared stented and non-stented patients undergoing PD to assess any differences in post-operative morbidity and mortality.

METHODS

A total of 180 consecutive patients who underwent PD and had intra-operative bile cultures performed between January 2010 and February 2013 were retrospectively identified. All patients received peri-operative intravenous antibiotic prophylaxis, primarily cefazolin.

RESULTS

Overall incidence of post-operative surgical complications was 52.3 %, with no difference between stented and non-stented patients (53.4 % vs. 51.1 %; p = 0.875). However, stented patients had a significantly higher incidence of deep incisional surgical site infections (SSIs) (p = 0.038). In multivariate analysis, biliary stenting was confirmed as a risk factor for deep incisional SSIs (p = 0.044). Significant associations were also observed for cardiac disease (p = 0.010) and BMI ≥25 kg/m(2) (p = 0.045). Enterococcus spp. were the most frequent bacterial isolates in bile (74.5 %) and in drain fluid (69.1 %). In antimicrobial susceptibilty testing, all Enterococci isolates were cefazolin-resistant.

CONCLUSION

Given the increased risk of deep incisional SSIs, preoperative biliary stenting in patients underging PD should be used only in selected patients. In stented patients, an antibiotic with anti-enterococcal activity should be chosen for PD prophylaxis.

Infections after T-replete haploidentical transplantation and high-dose cyclophosphamide as graft-versus-host disease prophylaxis

BACKGROUND

Recently, a platform of T-cell replete haploidentical hematopoietic stem cell transplantation (haplo-HSCT) using post-transplant cyclophosphamide (Cy) has shown high reproducibility and acceptable safety profile.

METHOD

This prospective cohort analysis allowed us to collect data on infections among 70 consecutive recipients of haplo-HSCT affected by various hematologic malignancies.

RESULTS

After a median follow-up of 23 months, cumulative incidence of viral infections was 70% (95% confidence interval [CI] 59-81) at 100 days and 77% (95% CI 67-87) at 1 year; 35 of 65 patients at risk had CMV reactivation (54%) and the rate of polyomavirus-virus-associated cystitis was 19% (13/70). Cumulative incidence of bacterial and fungal infections at 1 year were 63% (95% CI 51-75) and 12% (95% CI 4-19), respectively. Of note, only 1 invasive fungal infection occurred beyond 1 year after transplant (day +739).

CONCLUSION

In conclusion, despite a high rate of viral infections in the early period, present data suggest a satisfactory infectious profile after T-cell replete haplo-HSCT using post-transplant Cy. These results may help clinicians to improve both prophylactic and therapeutic antimicrobial strategies in this emerging haploidentical setting.

Multifocal diffusion of a KPC-3 producing ST512 K. pneumoniae clone in Northern Italy

Sequence Type 258 (ST258) together with its allelic single- and double-locus variants have mostly been associated with the dissemination of KPC-producing Klebsiella pneumoniae in Europe. A total of 56 nonreplicate K. pneumoniae isolates with decreased carbapenem-susceptibility, collected at 7 different hospitals located in Northern Italy were investigated for the occurrence of blaKPC-type genes. PCR and sequencing results highlighted the presence of blaKPC2 or blaKPC-3 determinants in 10/56 and 5/56 cases respectively. Here we describe the intra- and inter-hospital spread in Northern Italy of a K. pneumoniae ST512 clone harboring the blaKPC-3 gene.

Candidemia: species involved, virulence factors and antimycotic susceptibility

We investigate the characteristics of the Candida species involved in BSI episodes in our Institute, their phospholipase and protease activity and the susceptibility pattern towards the main antifungal agents currently available. From January 2009 to December 2010 we documented a total of 59 episodes of candidemia. The incidence of candidemia was 32% in General Surgery, 22% in the Intensive Care Unit (ICU), 13% in Oncology and 10% in Gastroenterology. C. albicans was the most common species (32 cases=48%), followed by C. glabrata (17 cases=26%) and C. parapsilosis (12 cases=18%), a significant production of phospholipase in all strains of C. albicans was detected. Among Candida non-albicans species, the production of this enzyme only occurred in 1/12 strains of C. parapsilosis. The expression acid protease production was detected in 48% of C. albicans and no strains of Candida non-albicans. All species of Candida were susceptible to amphotericin B. The rate of susceptibility to fluconazole was 100% for albicans and C. parapsilosis. Decreased susceptibility to fluconazole was mostly seen with C. glabrata, which was 76.5% susceptible in a dose-dependent manner. The echinocandins showed a good performance for C. albicans, and maintained a good MIC distribution in C. glabrata.

Gardnerella, Trichomonas vaginalis, Candida, Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum in the genital discharge of symptomatic fertile and asymptomatic infertile women

This study aimed to establish the different prevalence of the microorganisms investigated in the two groups considered: fertile women with symptoms and asymptomatic women with infertility problems. The data from women (n= 952) investigated for two years for quality of genital discharge and the presence of Gardnerella vaginalis, Trichomonas vaginalis, Candida species, Streptococcus agalactiae, Mycoplasma hominis, Ureaplasma urealyiticum and Chlamydia trachomatis were retrospectively analyzed. In the population of fertile women with symptoms the microrganisms most frequently involved are Gardnerella vaginalis (26.6%), Candida species (12.1%) and Streptococcus agalactiae (9.2%). The genital discharges of asymptomatic women with infertility problems are characterized by a prevalence of Gardnerella vaginalis (19.7%), Enterobacteriaceae or Enterococci (12.1%) and Streptococcus agalactiae (8.6%). The reduction of vaginal lactobacilli flora and the presence of an elevated number of polymorphonucleates in the vaginal discharge are important parameters to consider for the evaluation of the health status of the human female urogenital tract. Our results indicate that is important to culture the vaginal discharge for Streptococcus agalactiae and for prevalence of Enterobacteriaceae and Enterococci. Lastly, the reasons for the prevalence of some microorganisms (Gardnerella vaginalis, Enterobacteriaceae and Enterococci, Streptococcus agalactiae) in the population of infertile asymptomatic women need to be better analyzed especially after the recent studies correlating idiopathic infertility with the presence of cervical cytokines in women with an abnormal vaginal flora.

Prolonged effect of two combined methods for Legionella disinfection in a hospital water system

This study was conducted in our 650 bed general hospital, which is situated on the southern outskirts of Milan (Italy). After a first nosocomial case of pneumonia (caused by Legionella pneumophila serogroup 1), we first used a conventional method (heat shock) without success. To solve the problem we then tried a copper-silver ionization system combined with a chlorine dioxide device. During the four years after the installation of these two systems we recorded a significant (p < or = 0.05) reduction in Legionella colonization, and no new cases of Legionnaires' disease were observed. Our results suggest that the Cu-Ag ionization system, combined with a chlorine dioxide device, is a highly promising method for the control of Legionella pneumophila in a hospital water distribution system.

Aspergillus left ventricular assist device endocarditis

Left ventricular assist device (LVAD) support is an established therapy for patients with end-stage heart failure as a bridge to transplant; its usage as an alternative for those patients not eligible for transplant is not an established therapy yet. A 68-year-old male had a Thoratec-Heartmate LVAD implanted as destination therapy. After an uneventful (apart from early fever) recovery in the intensive care unit, the patient developed an intractable high temperature, and generalized sepsis and died 21 days following implant. The white cell blood count never exceeded the guard limits, and the patient succumbed with severe LVAD valve malfunction. At post-mortem examination friable material consisting of fungal hyphae was found on the inflow and outflow valves. According to published clinical trials, infection accounts for more than 40% of mortality in LVAD supported patients. Fungal LVAD endocarditis is a particularly deadly disease. Successful management requires a high level of suspicion and timely institution of antifungal therapy to control the infection. This has led some authors to recommend empiric antifungal therapy in LVAD recipients with culture-negative sepsis unresponsive to broad-spectrum antibiotics.

Antioxidant enzymatic activities and lipid peroxidation in cultured human chondrocytes from vertebral plate cartilage

In vitro models based on primary cultured human chondrocytes could be useful to study the ROS-mediated inflammatory processes that seem to involve chondrocytes in vivo. In this work, we studied the enzymatic antioxidative capability of human chondrocytes removed from vertebral plates during micro-discectomy and cultured 18 days, measuring total superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) activities. We also evaluated in the same cells the amount of malondialdehyde (MDA) in order to verify the effect of the variation of the cellular enzymatic antioxidative capability on the degree of membrane lipid peroxidation. Total SOD activity increased, even if not significantly, between the 12th and the 18th day. A significant variation of GSHPx (P<0.01) and of catalase (P<0.001) activity was observed between the 3rd and the 6th day with no further variation until the 18th day. A significant increase (P<0.001) of lipid peroxidation from the 3rd to the 18th day was also observed. These results seem to indicate that only fresh human cultured chondrocytes are suitable to study, through in vitro models, the in vivo behavior of the antioxidative status of these cells.

Deficiency of total collagen content and of deoxypyridinoline in intracranial aneurysm walls

The tissue contents of total collagen and of 3-hydroxypyridinium cross-links, pyridinoline (PYD) and deoxypyridinoline (DPD), were measured in 15 samples of human aneurysms of Willis' Circle obtained at surgery and in 25 autopsy control samples of intracranial arteries of Willis' Circle obtained from 6 subjects who died of other causes than cerebral hemorrhage. PYD and DPD were detected fluorimetrically after HPLC separation. Total collagen content was significantly lower (P < 0.001) in aneurysm samples (mean +/- S.E.M. 2.50 +/- 0.33 nmol of alpha 1(I) collagen chain per mg of delipidated and dried material) than in controls (mean +/- S.E.M. 3.86 +/- 0.14). DPD, but not PYD, content appears to be lower in aneurysm walls. In the aneurysms, the tissue contents of PYD ranged from 212 to 587 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 430 +/- 31) while in control samples the values observed ranged from 292 to 642 (mean +/- S.E.M. 471 +/- 21). The tissue content of DPD was measurable only in 6 aneurysm samples (60%), ranging from 12 to 60 pmol/nmol of alpha 1(I) collagen chain (mean +/- S.E.M. 33 +/- 9), while in control samples, DPD content ranged from 30 to 123 (mean +/- S.E.M. 75 +/- 5).

Ovariectomy in the rat induces a rapid increase in the urinary excretion of hydroxylysine glycosides and non-reducible crosslink residues

The ovariectomized rat is the most commonly used animal model of human postmenopausal osteoporosis, exhibiting a high rate of bone turnover with resorption exceeding formation. At present, bone turnover is quantified directly by dynamic histomorphometry. The aim of the present study was to determine whether the measurement of the urinary output of some specific bone collagen catabolites--pyridinolines and hydroxylysine glycosides--could be used to indirectly monitor the initial phase of bone turnover increase in ovariectomized 90-day-old rats. Ninety-day-old female rats were randomly divided into three groups (n = 6): ovariectomized, sham-operated and non-treated controls. Urine samples (24 h) were collected 6 days before surgery and twice weekly for the 4 weeks following ovariectomy. Urinary excretion of pyridinoline (PYD), deoxypyridinoline (DPD), glucosyl-galactosyl-hydroxylysine (GGHYL) and galactosyl-hydroxylysine (GHYL) were measured. As expected, ovariectomy was associated with a significant decrease in bone mineral density in both the proximal tibial and distal femoral metaphysis. Compared with both sham-operated and control animals, ovariectomized rats showed significant increases in PYD, GGHYL, and GHYL urinary output 8 days after surgery and in DPD output after 15 days. These changes were maintained throughout the study. The results confirm that measurement of the urinary excretion of pyridinolines and hydroxylysine glycosides represents a powerful tool for detecting the onset of bone turnover in ovariectomized 90-day-old rats.

Abnormalities of collagen cross-linkage in posterior communicating artery aneurysms: a preliminary study

The collagen of tissues submitted to mechanical load (i.e. arterial wall) is characterised by the presence of intermolecular covalent cross-links (hydroxylysyl pyridinoline or pyridinoline: PYD; and lysyl-pyridinoline or deoxypyridinoline: DPD) which stabilise the molecular structure. In this preliminary study we look for quantitative or qualitative alterations of collagen cross-linkage in intracranial aneurysms of posterior communicating artery (PCoA) which may be considered a site of elective weakening in the intracranial arterial circulation, being one of the most frequent locations of intracranial aneurysms and of so called "infundibular widening'. We analysed the collagen cross-linkage in 6 autopsy samples of intracranial arterial segments of the Circle of Willis which were removed from patients whose cause of death was other than cerebral hemorrhage, and in 6 samples of intracranial PCoA aneurysms obtained at surgery. The analysis of cross-links showed that there was no significant difference in collagen and cross-link content between autopic and aneurysmatic samples except for PCoA. In autoptic nonaneurysmatic samples of PCoA a lower content of PYD than in internal carotid artery (ICA) and a lower content of DPD than in all other arterial segments has been demonstrated; moreover a lower content of cross-links (DPD + PYD/ Collagen) was evident in nonaneurysmatic PCoA samples when compared to other segments (ICA and Anterior Communicating Artery). On the other hand, the mean content of DPD was significantly lower in PCoA aneurysms than in nonaneurysmatic samples of the artery and moreover, a significantly low content of cross-links (DPD + PYD/Collagen) is overemphasised in PCoA aneurysms, suggesting that the peculiar lower content of DPD in PCoA arteries may be considered the expression of minor resistance of the arterial wall at this site, and may be related to the higher incidence of aneurysms or infundibular widening of this arterial segment.

Urinary output of hydroxylysine glycosides and pyridinium cross-links in detecting rat bone collagen turnover rate

Glucosylgalactosylhydroxylysine (GGHYL), galactosylhydroxylysine (GHYL), pyridinoline (PYD) and deoxypyridinoline (DPD) were measured in the urine (6 h serial specimens over 96 and 24 h urine specimens for 4 days) collected from four adult Sprague Dawley rats and in the femoral and tibia] bone as well as in the dorsal skin of the same rats. No significant daily variations were found in the urine excretion of GGHYL, GHYL, PYD and DPD but significant diurnal variations. The GGHYL/GHYL ratio in rat urine (0.46 +/- 0.1) reflected neither the bone collagen ratio (1.9 to 2.4) nor the skin collagen ratio (1.22 +/- 1.07), a finding that may reflect GGHYL conversion into GHYL. The content of both pyridinolines was very low in the skin and high in the bone collagen and the urinary PYD/DPD ratio (1.46 +/- 0.15) reflected essentially the bone collagen ratio (0.8-3.0). These results suggest the usefulness of measuring GGHYL, GHYL, PYD and DPD in 24 h urine specimen and, based on the inter-animal variations, the necessity to consider each animal as its own control when bone turnover needs to be monitored.

High-performance liquid chromatographic method for measuring hydroxylysine glycosides and their ratio in urine as a possible marker of human bone collagen breakdown

Glucosyl-galactosyl-hydroxylysine (GGHYL) and galactosyl-hydroxylysine (GHYL) are constituents of collagen protein. The ratio of the two hydroxylysine glycosides varies with the collagen type and, moreover, for a given collagen type, it also varies according to the connective tissue. For example, in type I collagen (the most abundant in the body), the GGHYL/GHYL ratio tends to be greater in soft connective tissues and lower in bone. The hydroxylysine glycosides are not recycled during collagen turnover and are excreted in the urine. Therefore, the urinary GGHYL/GHYL ratio, which reflects the proportion of the two metabolites in the various collagens, may indicate the type of connective tissue affected by pathological turnover, and may thus be a promising marker of bone metabolism. In this paper a method is described for the measurement of urinary hydroxylysine glycosides by reversed-phase liquid chromatography after purification of the sample by solid-phase extraction. The method presented is analytically reliable and suitable for routine use in a clinical laboratory.

Isotopic and nonisotopic assays for measuring somatotropin compared: re-evaluation of cutoff value in provocative tests

Measurement of human growth hormone (hGH; somatotropin) concentrations in serum after provocative tests is crucial for diagnosing deficiencies in production of this hormone. Serum hGH can be measured by various immunoassays, isotopic and nonisotopic, with monoclonal or polyclonal antibodies: a cutoff value of 10 micrograms/L after provocative testing is usually used to distinguish normal from hGH-deficient children. Previous studies demonstrated discrepancies in hGH measurement by different radioisotopic immunoassays. Here we evaluated the responses of six different commercial assays, radioisotopic and nonisotopic, with monoclonal or polyclonal antibodies in a series of 16 provocative tests (stimulation with clonidine) in short children. A wide range of discrepant values was obtained with the different kits. A cutoff of 10 micrograms/L produced discordance of diagnosis among assays for two children, whereas complete agreement was reached for a cutoff value of 7 micrograms/L. Parallelism tests performed with hGH international standard, pure recombinant hGH, and a serum with high hGH content suggest that heterogeneity of the antibodies used by the manufacturers, even among monoclonal antibodies, is the main source of discordant results. Cutoff values and reference values must be established separately for each method proposed for routine use.