Intervertebral disc and endplate cells response to IL-1β inflammatory cell priming and identification of molecular targets of tissue degeneration

Inflammation represents an important factor leading to metabolic imbalance within the intervertebral disc (IVD), conducive to degenerative changes. Therefore, a thorough knowledge of the IVD and endplate (EP) cell behaviour in such pathological environments is essential when designing regenerative therapeutic strategies. The present study aimed at assessing the molecular response of the IVD constitutive nucleus pulposus (NPCs)-, annulus fibrosus (AFCs)- and endplate (EPCs)-derived cells to interleukin (IL)-1β treatment, through large-scale, high-throughput microarray and protein analysis, identifying the differentially expressed genes and released proteins. Overall, the inflammatory stimulus downregulated stemness genes while upregulating pro-inflammatory, pro-angiogenic and catabolic genes, including matrix metalloproteases, which were not balanced by a concomitant upregulation of their inhibitors. Upregulation of anti-inflammatory and anabolic tumour necrosis factor inducible gene 6 protein (TNFAIP6), of IL-1 receptor antagonist (IL-1Ra) (at gene and protein levels) and of trophic insulin-like growth factor 1 (IGF1) was also observed in all cell types; IGF1 particularly in AFCs. An overall inhibitory effect of tumour necrosis factor alpha (TNFα) signal was observed in all cell types; however, EPCs showed the strongest anti-inflammatory behaviour. AFCs and EPCs shared the ability to limit the activation of the signalling mediated by specific chemokines. AFCs showed a slightly senescent attitude, with a downregulation of genes related to DNA repair or pro-mitosis. Results allowed for the identification of specific molecular targets in IVD and EP cells that respond to an inflammatory environment. Such targets can be either silenced (when pathological targets) or stimulated to counteract the inflammation.

Intervertebral disc and endplate cell characterisation highlights annulus fibrosus cells as the most promising for tissue-specific disc degeneration therapy

Degenerative processes of the intervertebral disc (IVD) and cartilaginous endplate lead to chronic spine pathologies. Several studies speculated on the intrinsic regenerative capacity of degenerated IVD related to the presence of local mesenchymal progenitors. However, a complete characterisation of the resident IVD cell populations, particularly that isolated from the endplate, is lacking. The purpose of the present study was to characterise the gene expression profiles of human nucleus pulposus (NPCs), annulus fibrosus (AFCs) and endplate (EPCs) cells, setting the basis for future studies aimed at identifying the most promising cells for regenerative purposes. Cells isolated from NP, AF and EP were analysed after in vitro expansion for their stemness ability, immunophenotype and gene profiles by large-scale microarray analysis. The three cell populations shared a similar clonogenic, adipogenic and osteogenic potential, as well as an immunophenotype with a pattern resembling that of mesenchymal stem cells. NPCs maintained the greatest chondrogenic potential and shared with EPCs the loss of proliferation capability during expansion. The largest number of selectively highly expressed stemness, chondrogenic/tissue-specific and surface genes was found in AFCs, thus representing the most promising source of tissue-specific expanded cells for the treatment of IVD degeneration.

A Case Series and Literature Review of Isavuconazole Use in Pediatric Patients with Hemato-oncologic Diseases and Hematopoietic Stem Cell Transplantation

We analyzed the use of isavuconazole (ISA) as treatment or prophylaxis for invasive fungal disease (IFD) in children with hemato-oncologic diseases. A multicentric retrospective analysis was performed among centers belonging to the Italian Association for Pediatric Hematology and Oncology (AIEOP). Pharmacokinetic (PK) monitoring was applied by a high-performance liquid chromatography-tandem mass spectrometry (HLPC-MS/MS) assay. Twenty-nine patients were studied: 10 during chemotherapy and 19 after allogeneic hematopoietic stem cell transplantation (HSCT). The patients consisted of 20 males and 9 females with a median age of 14.5 years (age range, 3 to 18 years) and a median body weight of 47 kg (body weight range, 15 to 80 kg). ISA was used as prophylaxis in 5 patients and as treatment in 24 cases (20 after therapeutic failure, 4 as first-line therapy). According to European Organization for Research and Treatment of Cancer (EORTC) criteria, we registered 5 patients with proven IFD, 9 patients with probable IFD, and 10 patients with possible IFD. Patients with a body weight of <30 kg received half the ISA dose; the others received ISA on the adult schedule (a 200-mg loading dose every 8 h on days 1 and 2 and a 200-mg/day maintenance dose); for all but 10 patients, the route of administration switched from the intravenous route to the oral route during treatment. ISA was administered for a median of 75.5 days (range, 6 to 523 days). The overall response rate was 70.8%; 12 patients with IFD achieved complete remission, 5 achieved partial remission, 5 achieved progression, and 3 achieved stable IFD. No breakthrough infections were registered. PK monitoring of 17 patients revealed a median ISA steady-state trough concentration of 4.91 mg/liter (range, 2.15 to 8.54 mg/liter) and a concentration/dose (in kilograms) ratio of 1.13 (range, 0.47 to 3.42). Determination of the 12-h PK profile was performed in 6 cases. The median area under the concentration-time curve from 0 to 12 h was 153.16 mg·h/liter (range, 86.31 to 169.45 mg·h/liter). Common Terminology Criteria for Adverse Events grade 1 to 3 toxicity (increased transaminase and/or creatinine levels) was observed in 6 patients, with no drug-drug interactions being seen in patients receiving immunosuppressants. Isavuconazole may be useful and safe in children with hemato-oncologic diseases, even in the HSCT setting. Prospective studies are warranted.

Stability of housekeeping genes in human intervertebral disc, endplate and articular cartilage cells in multiple conditions for reliable transcriptional analysis

Quantitative gene expression analysis is widely used to evaluate the expression of specific tissue markers. To obtain reliable data it is essential to select stable housekeeping genes whose expression is not influenced by the anatomical origin of cells or by the culture conditions. No studies have evaluated housekeeping gene stability in intervertebral disc (IVD) cells and only few studies using cartilaginous endplate (CEP) and articular cartilage (AC) cells are present in the literature. We analysed the stability of four candidate housekeeping genes (GAPDH, TBP, YWHAZ and RPL13A) in human cells isolated from nucleus pulposus (NP) and annulus fibrosus (AF), CEP and AC. Cell isolation, expansion, cryoconservation, and differentiation in 3D pellets were tested. GeNorm, NormFinder, BestKeeper tools and the comparative ΔCt method were used to evaluate housekeeping gene stability. In each cell population, TBP alone or combined with YWHAZ was identified as the best normaliser in both monolayer and 3D pellets. GAPDH was the best performer only for AC cells in monolayer. In most culture conditions considering groups of two or more cell types, TBP was the most stable and YWHAZ was the second choice. GAPDH was the best performer only in 3D pellets with factors for AC and AF combined with CEP cells. RPL13A was the most stable only for AF with CEP cells at isolation. Our findings will be useful to properly design the experimental set-up of studies involving IVD, CEP or AC cells in different culture conditions, in order to obtain accurate and high quality data from quantitative gene expression analysis.

Modifications of biochemical parameters related to protein metabolism and renal function in male soccer players after a match

AIM

The impact of a soccer match on parameters related to protein catabolism and renal function was evaluated in male players.

METHODS

Blood was collected before and immediately after a 90 minutes soccer match from 19 athletes of two first division teams in Brazil. Red blood cells (RBC), hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC), ammonia, uric acid, urea and creatinine were analyzed. The modification of plasma volume was calculated, and biochemical values were corrected for this change. Urea/creatinine ratio and equations to estimate the glomerular filtration rate (eGFR) were used to assess kidney function.

RESULTS

Plasma volume decreased from pre- to post-match. Post-match values higher than the pre-match ones were observed for RBC, Hb and Ht, as a consequence of plasma volume decrease. An increase in ammonia and creatinine concentrations post-match in comparison with pre-match values was registered, without changes in uric acid and urea levels. A reduction in urea/creatinine ratio and in eGFR was observed post-match, suggesting a decrease of renal function.

CONCLUSION

A soccer match induced alterations in parameters linked to renal function and protein metabolism in male athletes. Particular attention should be paid in the monitoring of the ammonia concentration as an indicator of metabolic activity and energy requirement during prolonged exercise.

Donor-matched mesenchymal stem cells from knee infrapatellar and subcutaneous adipose tissue of osteoarthritic donors display differential chondrogenic and osteogenic commitment

Cell-based therapies have recently been proposed for the treatment of degenerative articular pathologies, such as early osteoarthritis, with an emphasis on autologous mesenchymal stem cells (MSCs), as an alternative to terminally differentiated cells. In this study, we performed a donor-matched comparison between infrapatellar fat pad MSCs (IFP-MSCs) and knee subcutaneous adipose tissue stem cells (ASCs), as appealing candidates for cell-based therapies that are easily accessible during surgery. IFP-MSCs and ASCs were obtained from 25 osteoarthritic patients undergoing total knee replacement and compared for their immunophenotype and differentiative potential. Undifferentiated IFP-MSCs and ASCs displayed the same immunophenotype, typical of MSCs (CD13+/CD29+/CD44+/CD73+/CD90+/CD105+/CD166+/CD31-/CD45-). IFP-MSCs and ASCs showed similar adipogenic potential, though undifferentiated ASCs had higher LEP expression compared to IFP-MSCs (p<0.01). Higher levels of calcified matrix (p<0.05) and alkaline phosphatase (p<0.05) in ASCs highlighted their superior osteogenic commitment compared to IFP-MSCs. Conversely, IFP-MSCs pellets showed greater amounts of glycosaminoglycans (p<0.01) and superior expression of ACAN (p<0.001), SOX9, COMP (p<0.001) and COL2A1 (p<0.05) compared to ASCs pellets, revealing a superior chondrogenic potential. This was also supported by lower COL10A1 (p<0.05) and COL1A1 (p<0.01) expression and lower alkaline phosphatase release (p<0.05) by IFP-MSCs compared to ASCs. The observed dissimilarities between IFP-MSCs and ASCs show that, despite expressing similar surface markers, MSCs deriving from different fat depots in the same surgical site possess specific features. Furthermore, the in vitro peculiar commitment of IFP-MSCs and ASCs from osteoarthritic donors towards the chondrogenic or osteogenic lineage may suggest a preferential use for cartilage and bone cell-based treatments, respectively.

Salivary steroid hormone response to whole-body cryotherapy in elite rugby players

Saliva represents a low stress, not-invasively collected matrix that allows steroid hormone monitoring in athletes by reflecting type, intensity and duration of exercise. Whole body cryotherapy (WBC) consists of short whole-body exposures to extremely cold air (-110° to -140°C) which, despite being initially used to treat inflammatory diseases, is currently acquiring increasing popularity in sports medicine. Cryostimulation practice is now widely accepted as an effective treatment to accelerate muscle recovery in rugby players. The aim of this work was to study the changes of steroid hormones in saliva of rugby players after both 2 and 14 consecutive WBC sessions, in order to investigate the effects of the treatment on their salivary steroid hormonal profile. Twenty-five professional rugby players, belonging to the Italian National Team, underwent a 7-day cryotherapy protocol consisting of 2 daily sessions. Saliva samples were taken in the morning prior to the start of the WBC, in the evening after the end of the second WBC, and in the morning of the day after the last WBC session. The samples were analyzed for cortisol, DHEA, testosterone and estradiol using competitive enzyme-linked immunosorbent assays. Cortisol and DHEA showed a reduction already after the 2 WBC sessions of the first day; after 14 consecutive WBC sessions cortisol, DHEA, and estradiol levels decreased, while testosterone increased as did the testosterone to cortisol ratio. These results were confirmed by the fact that the majority of subjects showed variations exceeding the critical difference (CD). In conclusion, we found that WBC acutely affects the salivary steroid hormone profile, and the results are evident already after only one twice-daily session. Most significantly, after one-week of consecutive twice-daily WBC sessions, all the hormones were modified. This is the first experimental report that links changes in the hormonal asset to WBC.

Reciprocal regulation of calcium-/phosphate-regulating hormones in cyclists during the Giro d'Italia 3-week stage race

Calcium and phosphate are essential for cell functions, and their serum concentrations result from the balance between intestinal absorption, bony storage, and urinary excretion. Fibroblast growth factor 23 (FGF23), expressed by osteocytes and osteoblasts, acts in the kidney, leading to hypophosphatemia and low 1,25-dihydroxycholecalciferol synthesis, but suppresses parathyroid function. The aim of this study was to explore the effects of a high-energy demanding cycling race on this bone-kidney-parathyroid axis. We studied nine cyclists during the 2011 Giro d'Italia stage race. Pre-analytical and analytical phases followed academic and anti-doping recommendations. Serum parathyroid hormone (PTH), 25(OH)D, total calcium, inorganic phosphorus, and plasma FGF23 were measured on days -1, 12, and 22 and corrected for changes in plasma volume. Dietary calcium and phosphorus, anthropometric parameters (height, weight, and body mass index) and indexes of metabolic effort (net energy expenditure, power output) were recorded. Dietary calcium and phosphorus intakes were kept at the same levels throughout the race. Twenty-five (OH)D, PTH, and calcium concentrations remained stable. FGF23 increased 50% with a positive correlation with the indexes of metabolic effort and, consequently, phosphorous decreased, although only in the first half. The strong metabolic effort acts on the bone-kidney-parathyroid system, and the rise in FGF23 plasma concentration might be aimed at maintaining calcium and phosphorus homeostasis.

Sclerostin concentrations in athletes: role of load and gender

Bone mass is the net product of formation and resorption, which are closely regulated by the equilibrium between endogenous/exogenous factors. Sclerostin inhibits the Wnt canonical signaling and is considered an anti-anabolic factor. We compared sclerostin serum concentrations between genders in athletes belonging to different sport disciplines, characterized by a different weight-bearing, and in their sedentary counterparts in order to study the possible link between bone metabolism in athletes and its peripheral concentration. We also compared sclerostin levels with bone alkaline phosphatase activity, a marker of bone formation. Sixty-one elite athletes, belonging to weight-bearing (15 male rugby players, 11 male enduro racers, 8 female basketball players), high-impact (6 male tennis players, 8 female ice skaters), non weight-bearing sports (13 male cyclists) and 16 sedentary controls were enrolled. Higher levels of sclerostin were found in females. Sclerostin was higher in weight-bearing than in non-weight-bearing disciplines in males. Significant inverse age-related correlation was found. Higher bone alkaline phosphatase activity was observed in females. The young adult elite athlete represents a peculiar physiologic model for studying sclerostin behavior: the applied load increased the marker concentrations, testifying a high bone turnover rate; however, a gender effect is evident.

Microbially-enhanced composting of wet olive husks

The production of a compost from olive wet husks is described. The process is enhanced through the use of starters prepared with virgin husks enriched with selected microbial cultures. This approach, with respect to composting without the use of starters, allows to achieve faster start of the process (10 vs. 45 days), deeper humification (humification rate 19.2 vs. 12.2), shorter maturation time (2 vs. 4-5 months) and better detoxification of the starting material. Furthermore, the compost produced can effectively substitute for turf as a cultivation substrate in horticulture at greenhouse level, with beneficial effects on nutraceutical traits of tomato fruits.

Bone fractures and hypoglycemic treatment in type 2 diabetic patients: a case-control study

OBJECTIVE

Hypoglycemic treatments could modulate the risk for fractures in many ways. Most studies have not explored the effect on the incidence of bone fractures of individual oral hypoglycemic agents, rather all oral treatments as a whole. The aim of this case-control study, nested within a retrospective cohort, is the assessment of the risk for bone fractures associated with exposure to insulin or different oral hypoglycemic agents.

RESEARCH DESIGN AND METHODS

A case-control study nested within a cohort of 1,945 diabetic outpatients with a follow-up of 4.1 +/- 2.3 years was performed, comparing 83 case subjects of bone fractures and 249 control subjects matched for age, sex, duration of diabetes, BMI, A1C, comorbidity, smoking, and alcohol abuse. Exposure to hypoglycemic drugs during the 10 years preceding the event (or matching index date) was assessed.

RESULTS

In a model including treatment with insulin secretagogues metformin and insulin for at least 36 months during the previous 10 years, no significant association was observed between bone fractures and medications. In an alternative model considering treatments at the time of fracture, insulin treatment was significantly associated with bone fractures in men (OR 3.20 [95% CI 1.32-7.74]) but not in women (1.41 [0.73-2.73]).

CONCLUSIONS

Insulin-sensitizing treatment with metformin is not associated with a higher incidence of bone fractures, suggesting that the negative effect of thiazolidinediones is due to a specific action on bone metabolism rather a reduction of insulinemia. Conversely, current treatment with insulin increases the risk of fractures; at the same time, exposure to this agent in the longer term does not appear to affect bone frailty.

Screening of older community-dwelling people at risk for death and hospitalization: the Assistenza Socio-Sanitaria in Italia project

OBJECTIVES

To develop and validate mortality and hospitalization prognostic tools based upon information readily available to primary care physicians (PCPs).

DESIGN

Population-based cohort study. Baseline predictors were patient demographics, a seven-item questionnaire on functional status and general health, use of five or more drugs, and previous hospitalization.

SETTING

Community-based study.

PARTICIPANTS

Prognostic indexes were developed in 2,470 subjects and validated in 2,926 subjects, all community-dwelling, aged 65 and older, and randomly sampled from the rosters of 98 PCPs in Florence, Italy.

MEASUREMENTS

Fifteen-month mortality and hospitalization.

RESULTS

Two scores were derived from logistic regression models and used to stratify participants into four groups. With Model 1, based upon the seven-item questionnaire, mortality rate ranged from 0.8% in the lowest-risk group (0-1 point) to 9.4% in the highest risk group (> or = 3 points), and hospitalization rate ranged from 12.4% to 29.3%; area under the receiver operating characteristic curves (AUC) was 0.75 and 0.60, respectively. With Model 2, considering also drug use and previous hospitalization, mortality and hospitalization rates ranged from 0.3% to 8.2% and from 8.1% to 29.7%, for the lowest-risk to the highest-risk group; the AUC increased significantly only for hospitalization (0.67).

CONCLUSION

Prediction of death and hospitalization in older community-dwelling people can be easily obtained with two indexes using information promptly available to PCPs. These tools might be useful for guiding clinical care and targeting interventions to reduce the need for hospital care in older persons.

Extradural motor cortex stimulation as a method to treat advanced Parkinson's disease: new perspectives in geriatric medicine

Motor fluctuations not controlled by pharmacological therapy are often encountered in long-term Parkinson's disease (PD). Neurosurgery treatment represented by deep brain stimulation (DBS) was considered a valid alternative to pharmacological treatment. Unfortunately this method is most effective in patients under age of 70. Recently it has been suggested that extradural motor cortex stimulation (EMCS) could be a valid cost-effective alternative to DBS to control motor symptoms in patients affected by Parkinson's disease. The relevant non-invasive surgical technique makes this treatment particularly indicated in geriatric patients. Brain atrophy, cognitive impairment, psychiatric symptoms are not an absolute contraindication to the treatment. We submitted to EMCS an outpatient afferent to our geriatric department, a woman 68 yrs old. The patient showed an improvement of 35% as measured by the Unified Parkinson Disease Rating Scale (UPDRS) scale after the surgery. If our findings will be confirmed in larger series, a new dimension will be added to the treatment of PD.

Sleep apnea and respiratory dysfunction in congenital myotonic dystrophy

A case of neonatal Myotonic Dystrophy (MD) is presented. A 35 week old 3570 g baby was born to a mother affected by MD and pregnancy-induced unstable diabetes. Soon after birth, he developed apnea, severe hypoglycemia, hypocalcemia, hypotonia and mild respiratory distress. His clinical course improved during the following days, but persistent episodes of desaturation and/or cyanosis did not subside; hypotonia was mild. A polysomnographic recording showed mixed central and obstructive apnea. DNA testing showed trinucleotide repeat expansion mutations diagnostic of MD. The baby was discharged with home-sleep monitoring and breast-feeding. Recurrent apnea/bradycardia was the main clinical feature in this case of congenital MD, with increased risk of an acute life-threatening event.

Acute myositis following autologus bone marrow transplantation (BMT)

A 4-year-old boy with acute myeloid leukemia developed acute myositis associated with refractory thrombocytopenia one month after autologous bone marrow transplantation (BMT). Clinical, electromyographic and biohumoral features were consistent with the diagnosis of myositis. The patient responded to corticosteroids, and 39 months after BMT he is in complete remission and has regained good muscle function. Although we could not determine with certainty the specific pathophysiologic mechanism of this complication, it should be pointed out that acute myositis can occur in the early post-BMT period.

Capillary blood lactate concentrations during intermittent all-out exercise

The average maximal peak torques of the knee extensor and knee flexor muscles were measured during one, two or three series of 20 maximal contractions at an angular velocity of pi rad s(-1). Each series lasted about 20 s. After the first series, a 10 min rest was allowed before the second series of contractions. In one case only was a third series of contractions performed. Various sequences of contractions of the dominant and contralateral limbs were tested. Capillary blood lactate concentration ([LA]cap) was determined in the blood samples taken from an earlobe during each recovery. The difference between peak capillary blood lactate concentration and the concentration that would have occurred without any previous contraction (delta[LA]cap) was taken as the index of metabolic comparison between the exercise bouts. The mechanical power output during the first series of contractions was similar to that in the second and third series, but the lactate elevation was significantly higher in the first series. The discrepancy between the constancy of the power output and the decrease in lactate elevation was even more evident if delta[LA]cap was calculated as the difference between peak capillary blood lactate concentration and the value measured immediately before the second or third series. The decrease in lactate elevation was not affected by the change of the contracting limb from the first to the second series. In conclusion, the capillary blood lactate concentration profile during intermittent maximal exercise cannot be considered a suitable technique for evaluating lactate production.

Six years' experience of total parenteral nutrition in children with hematological malignancies at a single center: management, efficacy, and complications

Total parenteral nutrition (TPN) is an important issue in supportive care of children with leukemia. We studied 131 consecutive children (87 male, 44 female) with hematological malignancies who received TPN at our center from July 1984 to July 1990 with the aim of evaluating the efficacy and complications of TPN. The use of TPN was associated with lack of any alteration of the anthropometric indexes used in this study. The complications were prevalently metabolic, generally mild, and easily controlled. Laboratory monitoring of nutritional status during TPN is probably of little value in this setting. The feasibility of in-ward preparation of TPN by nurses makes TPN possible at low cost provided that patients are selected carefully.

Peak blood lactate and blood lactate vs. workload during acclimatization to 5,050 m and in deacclimatization

Peak blood lactate ([Labl]peak) and blood lactate concentration ([Labl]) vs. workload (W) relationships during acclimatization to altitude and in the deacclimatization were evaluated in 10 Caucasian lowlanders at sea level (SL0); after approximately 1 wk (Alt1wk), 3 wk (Alt3wk), and 5 wk (Alt5wk) at 5,050 m; and weekly during the first 5 wk after return to sea level (SL1wk-SL5wk). Incremental bicycle ergometer exercises (30 W added every 4 min up to exhaustion) were performed. At Alt1wk and at Alt5wk, the experiments were repeated in hypobaric normoxia (Alt1wk-O2 and Alt5wk-O2). [Labl] was determined at rest and during the last approximately 30 s of each W. [Labl]peak was taken as the highest [Labl] during recovery. Acid-base status (pH and concentration of HCO-3 in arterialized capillary blood) was determined at rest. Mean [Labl]peak values were 11.5 (SL0), 8.0 (Alt1wk), 6.4 (Alt3wk), 6.3 (Alt5wk), 8.0 (SL1wk), 9.4 (SL2wk), 10.8 (SL3wk), 11.3 (SL4wk), and 11.6 (SL5wk) mM. At Alt1wk-O2 and Alt5wk-O2, peak W increased, compared with Alt1wk and Alt5wk, whereas no changes were observed for [Labl]peak. [Labl] vs. W was shifted to the left (i.e., higher [Labl] values were found for the same W) at Alt1wk compared with SL0 and partially shifted back to the right (i.e., lower [Labl] values were found for the same W) at Alt3wk and Alt5wk. At Alt1wk-O2 and Alt5wk-O2, [Labl] vs. W values were superimposed on that at SL0. At SL1wk-SL5wk, [Labl] vs. W values were shifted to the right compared with that at SL0. At Alt1wk, a condition of respiratory alkalosis was found, which was only partially compensated for during acclimatization. At SL1wk, the acid-base status was back to normal. We conclude that 1) the reduced [Labl]peak at altitude is still present for 2-3 wk after return from altitude; is not attributable to reduced peak W nor to hypoxia per se, nor to a reduced buffer capacity; alternatively, it could be related to some central determinants of fatigue. 2) The [Labl] vs. W leftward shift at altitude was due to hypoxia per se. 3) The factor(s) responsible for the [Labl] vs. W partial rightward shift during acclimatization could still be effective during the first weeks after return to sea level.

Maximal rate of blood lactate accumulation during exercise at altitude in humans

The lower peak lactate accumulation in blood ([La(b)]p) at altitude may be associated with a reduced maximal glycolytic flux. Based on certain assumptions, the latter can be indirectly evaluated in vivo, during short supramaximal exercises, by measuring the maximal rate of lactate accumulation in blood (delta [La(b)]max). delta [La(b)]max was determined on six white subjects at sea level (SL1), after approximately 1 wk (Alt1) and 4 wk (Alt2) of a 35-day sojourn at 5,050 m, and 1 wk after return to sea level (SL2). The subjects performed exercises of increasing duration (5, 15, 25, 35, 45 s or until exhaustion) on a bicycle ergometer at loads = 200% of the individual Wmax. The latter was previously determined in each condition as the greatest work rate that could be sustained for 2-4 min during an incremental exercise. Net [La(b)] accumulation (delta [La(b)]) was measured after each exercise bout. delta [La(b)] resulted to be linearly related to exercise duration. The slopes of the individual delta [La(b)] vs. exercise duration lines were taken as delta [La(b)]max. Exhaustion times were approximately 30-45 s in all conditions. [La(b)]p (in mM) during recovery after the exhaustive load was higher at SL1 (10.22 +/- 1.09; means +/- SD) than at Alt1 (5.08 +/- 0.82), Alt2 (8.13 +/- 2.67), and SL2 (8.18 +/- 1.43). delta [La(b)]max was lower at Alt1 (0.09 +/- 0.02) and at Alt2 (0.17 +/- 0.05) than at SL1 (0.25 +/- 0.05) and SL2 (0.23 +/- 0.06). Both [La(b)]p and delta [La(b)]max increased during acclimatization.(ABSTRACT TRUNCATED AT 250 WORDS)

Central venous catheter clots: incidence, clinical significance and catheter care in patients with hematologic malignancies

In a 7-month period we studied 38 Hickman central venous catheters (CVCs) positioned in children with hematologic malignancies with the aim of evaluating the incidence and clinical impact of CVC clots. Clots were found in 74% of the CVCs. Three methods of catheter care were developed for flushing the clotted CVCs: (a) use of a heparinized solution (400 IU/mL) on alternate days, (b) use of a heparinized solution (400 IU/mL) and saline solution containing urokinase (10,000 IU/mL) on alternate days, and (c) use of a saline solution containing urokinase (10,000 IU/mL) daily. Only method b decreased clot formation (33% success rate). There were no major mechanical complications in any of the CVCs with clots. Eighteen percent of patients with clots in their CVCs presented with CVC-related infections while no infective complications were observed in the patients without clots in their CVCs. In conclusion, CVC clots may predispose the patient to infections, which must be correctly treated.

Retro-orbital late relapse in a child with leukaemia after allogeneic bone marrow transplantation

Relapse after allogeneic bone marrow transplantation (BMT) usually occurs in the bone marrow and is often associated with a poor prognosis. Isolated extramedullary relapse following BMT is exceedingly rare. We observed an isolated relapse in the left retro-orbital region of a 13-year-old girl, 3 years after BMT performed for acute lymphoblastic leukaemia in third complete remission. Computerized tomography revealed a tumor at the inferomedial part of the orbit infiltrating the maxillary and ethmoid sinuses and nasal cavities and also involving the rectus muscles. Histology demonstrated a monomorphic leukaemia infiltrate. Complete disappearance of the retro-orbital mass was obtained with chemotherapy and local irradiation.

The metabolic and ventilatory response to exercise in Tibetans born at low altitude

The exercise response of 20 Tibetans (T) born and living in Kathmandu, Nepal (1300 m) was compared to that of 21 age- and sex-matched local lowlanders. The subjects carried out an incremental exercise protocol on a bicycle ergometer (30 watt steps every 4 min) until exhaustion. The kinetics of readjustment of VO2 measured as half time (t-on) upon a 90 watt constant load exercise was also determined. Breath-by-breath gas exchange, heart rate (HR) and blood lactate concentration ([La]) were measured at rest, at the end of each load and during recovery. The slope of the straight line relating VO2 to work load was 10.8 ml.watt-1 in both groups which corresponds to a mechanical efficiency of 0.26 (assuming a RQ of 0.89 and an energy equivalent of 20.9 kJ.L-1 O2). At submaximal loads T were characterized by higher VE (P < 0.05), VE.VO2(-1) (P < 0.01) and VCO2 levels (P < 0.001) than N. The found higher VE in T, resulting from a lower tidal volume coupled to a higher respiratory frequency, led to higher PETO2 (P < 0.001) and SaO2 (P < 0.001) at all work levels. Absolute VO2max in the two investigated groups were 1977 +/- 72 (T) and 2095 +/- 80 (N) ml.min-1 (NS). Specific (i.e. per kg body weight) VO2max were identical (37.0 +/- 1.1 [T] vs. 36.7 +/- 1.1 ml.kg-1.min-1 [N]). [La]max were 11.4 +/- 0.4 (T) vs. 12.3 +/- 0.4 (N) mM (NS). [La] accumulation in blood as a function of workload and its rate of disappearance during recovery were similar. t-on at 90 watt was 30.7 +/- 2.4 sec in T and 28.9 +/- 2.3 sec in N (NS). The corresponding average contracted O2 deficit were 971 ml for T and 994 ml for N (NS). In conclusion, Tibetans born at low altitude do not seem to differ from lowlanders with regard to their metabolic response whereas their ventilatory response to exercise is greater.

Growth hormone and insulin-like growth factor I in athletes performing a marathon at 4000 m of altitude

Human growth hormone (hGH) characteristically increases during physical exercise. In sports medicine, hGH changes have mostly been described in short-term performances under standardized laboratory procedures. We studied hGH and insulin-like growth factor I (IGF-I) under field conditions in 7 runners performing a marathon at 4000 m of altitude, to study the hormonal changes under extreme endurance effort and to evaluate the release of 22 kDa and 20 kDa monomers under these conditions, in comparison with a control group. The blood samples were taken at sea level, after 1 week of acclimatization, immediately after the run, and after a recovery of 24 h from the marathon. hGH was quantified by using a polyclonal method, a 22 kDa specific monoclonal method and a monoclonal method recognizing both 22 kDa and 20 kDa isoforms. A significant increase in hGH was noted using all methods after the marathon, followed by a significant decrease after recovery. Significant differences between athletes and controls were found only for the measurement after the marathon. No statistically reliable decrease of IGF-I was observed in athletes and controls. We obtained more limited hGH rises than previously described in athletes; the importance of lactate levels indicates that the use of physical exercise as a stimulation test for hGH should be closely standardized. The 20 kDa monomer and other hGH molecular forms played a limited role in the hormone increase: in our experience, elevation of hGH in heavy exercise corresponds mostly to the 22 kDa isoform. We suggest that the evaluation of hGH elevation in sports medicine could be accurately performed using specific 22 kDa monoclonal assays.

The energy cost of level cross-country skiing and the effect of the friction of the ski

Oxygen consumption [(VO2) in ml.kg-1.min-1], blood lactate concentration ([La] in mM) and dynamic friction of the skis on snow [(F) in N] were measured in six athletes skiing on a level track at different speeds [(v) in m.min-1] and using different methods of propulsion. The VO2 increased with v and F, the latter depending mostly on snow temperature, as did [La]. The VO2 was very much affected by the skiing technique. Multiple regression equations gave the following results: with diagonal stride (DS), VO2 = -23.09 + 0.189 v + 0.62 N; with double pole (DP), VO2 = -30.95 + 0.192 v + 0.51 N; and with the new skating technique (S), VO2 = -32.63 + 0.171 + 0.68 N. In terms of VO2 DS is the most expensive technique, while S is the least expensive; however, as F increases, S, at the highest speed, tends to cost as much as DP. At speeds from 18 to 22 km.h-1, the speeds measured in the competitions, the F for DS and DP can represent from 10% to 50% of the energy expenditure, with F ranging from 10 to 60 N; with S this range increases to 20%-70%. This seems to depend on the interface between the skis and the snow and on the different ways the poles are used.

Gas exchange and metabolic transients in heart transplant recipients

In human heart transplant recipients (HTR) an impairment of the cardiac function was expected to reduce peak oxygen consumption and the kinetics of the adjustment of respiratory gas exchange at the onset of rectangular work loads. In nine patients (males, 23-59 yr) 1 to 8 months after cardiac transplantation average peak VO2 (VO2p) was 1.1 L.min-1 +/- 0.3 (SD), i.e. 45% of that of the controls, the corresponding VCO2p value being 1.4 L.min-1 +/- 0.3 (SD). Mean VEp was 62.9 L.min-1 +/- 20.3 (SD), mean HRp was 136 beats.min-1 +/- 11 (SD), i.e. 45 beats.min-1 higher than preexercise values. Mean [Lab]p was 7.7 mM +/- 1.7 (SD), indicating that at the heaviest load the HTR were performing work at or above their maximum aerobic power. During the initial 60-90 sec of the transition from rest to graded rectangular exercise HR did not change from the resting value, increasing thereafter almost linearly with time. The half time (t1/2) of the VE on-response was 112 sec +/- 30 (SD) (controls values: 59 sec +/- 16), that of the VCO2 on- was 95 sec +/- 18 (SD) (58 sec +/- 11), and that of the VO2 on- was 78 sec +/- 24 (SD) (38 sec +/- 6). In spite of the slow kinetics of the VO2 on- response, no massive accumulation of lactate was found in the early phase of exercise. The limitation of the peak exercise in HTR appears to be imposed by a reduced maximal cardiac performance. The slow readjustment of the latter, as expected from the sluggish heart rate response, however, does not impair substantially the work load transients nor reduce the anaerobic threshold.

[Vertical transmission of hepatitis B (new personal case in a newborn infant)]

A case of acute B hepatitis in a male 3 month-old baby born to an asymptomatic-HBsAg-carrier mother is reported. There is a good evidence to support the hypothesis of a vertical transmission at delivery. In fact the mother failed to exhibit any reactivity for e/anti-e system and resulted DNA-polymerase negative.

Passive oral immunization with bovine immunoglobulins: enterpathogenic Escherichia coli from infants and bovine anti-E. coli lactoserum assayed in the rabbit ileal loop model

The effect of immune bovine lactoserum (BLS) antipolyvalent enteropathogenic Escherichia coli on bacterial growth, viability and bacteria-induced fluid accumulation was examined in rabbit ileal loops. Human enteropathogenic E. coli strains 0125:K70 (B15), 0111:K58 (B4) and 055:K59 (B5) (1-3 X 10(9) per inoculum) induced secretion of 4-6 ml fluid per 10 cm loop. This effect was inhibited effectively by BLS (corresponding to 50 mg IgG 1 per loop) while the viability of bacteria counts decreased 2-25 fold compared with bovine serum albumin. E. coli 026:K60 (B6), 0126:K71 (B16) and 0127:K63 (B8) caused moderate secretion (2-3 ml/10 cm loop) that was significantly neutralized by BLS. E. coli 086:K61 (B7) and 0128:K67 (B12) did not give positive loops. The fluid secretion was shown to be dose dependent for E. coli 0125:K70 (B15) over the range from 2.5 X 10(9) to 8 X 10(7) bacteria/loop. The titration of the effect of BLS on fluid secretion caused by the same strain revealed a dose dependent decrease. The best inhibition was obtained with 100 mg BLS/loop, the highest dose tested.