[Development of a device allowing for the perfusion and preservation of rat kidneys at -4 degrees C]

OBJECTIVES

In order to prolong the cold ischaemia time and to improve the quality of donor kidneys, we have designed and developed a renal perfusion machine allowing the control of perfusion parameters (temperature, pressure, flow rate, resistance) during the various phases of a kidney perfusion and storage protocol at -4 degrees C.

ANIMALS, MATERIALS AND METHODS

Twenty four rat kidneys were removed and the effects of perfusion and storage at -4 degrees C were studied using a perfusion/storage machine allowing the controlled addition of 2,3 butanediol in University of Wisconsin (UW solution). The kidneys were stored for 96 hours at -4 degrees C and were studied in terms of perfusion parameters (pressure, resistance) and according to their histological appearance.

RESULTS

The machine allows controlled perfusion of a cryoprotective agent and preservation of kidneys at -4 degrees C for 96 hours.

CONCLUSION

In animals, it is possible to store kidneys at a temperature of -4 degrees C for 96 hours by using a vecor solution (UW solution) and a cryoprotective agent (2,3 butanediol). The perfusion and storage of organs under these conditions must be performed by a computer-assisted machine, allowing monitoring and control of the various steps of perfusion/storage.

Human quadriceps cross-sectional area, torque and neural activation during 6 months strength training

Quadriceps muscle and fibre cross-sectional areas (CSA), torque and neural activation were studied in seven healthy males during 6 months of weight training on alternate days with six series of eight unilateral leg extensions at 80% of one repetition maximum. After training, the quadriceps cross-sectional area increased by 18.8 +/- 7.2% (P < 0.001) and 19.3 +/- 6.7% (P < 0.001) in the distal and proximal regions respectively, and by 13.0 +/- 7.2% (P < 0.001) in the central region of the muscle. Hypertrophy was significantly different between and within the four constituents of the quadriceps. Biopsies of the vastus lateralis at mid-thigh did not show any increase in mean fibre cross-sectional area. Maximum isometric voluntary torque increased by 29.6 +/- 7.9%-21.1 +/- 8.6% (P < 0.01-0.05) between 100 degrees and 160 degrees of knee extension, but no change in the optimum angle (110 degrees-120 degrees) for torque generation was found. A 12.0 +/- 10.8% (P < 0.02) increase in torque per unit area together with a right shift in the IEMG-torque relation and no change in maximum IEMG were observed. Time to peak isometric torque decreased by 45.8% (P < 0.03) but no change in time to maximum IEMG was observed. In conclusion, strength training of the quadriceps results in a variable hypertrophy of its components without affecting its angle-torque relation. The increase in torque per unit area, in the absence of changes in IEMG, may indicate changes in muscle architecture. An increase in muscle-tendon stiffness may account for the decrease in time to peak torque.

Identification of cyclic AMP-phosphodiesterase variants from the PDE4D gene expressed in human peripheral mononuclear cells

To determine whether the expression of different PDE4D variants is unique to the rat or conserved through evolution, we have characterized the different PDE4D mRNAs expressed in human peripheral blood mononuclear cells. RT-PCR was performed using primers based on rat sequences and mRNAs from mononuclear cells. The specifically amplified fragments had a size identical to that predicted for rat PDE4D1, PDE4D2 and PDE4D3. Sequencing confirmed that these fragments are derived from the human PDE4D gene. Their sequence was highly homologous to that reported for the rat variants. cDNAs corresponding to the entire ORF of human PDE4D2 and PDE4D3 were expressed in mammalian cells, causing a large increase in PDE activity. Western blot analysis of human peripheral blood mononuclear cell extracts demonstrated the presence of proteins corresponding to the recombinant PDE4D1 and PDE4D2. The pattern of splicing and different promoter usage of the PDE4D gene is therefore conserved during evolution, which indicates an important physiological role.

Extinction of peroxisomal functions in hepatoma cell-fibroblast hybrids

Although peroxisomes are ubiquitous, differences in the number of organelles and in the expression of associated metabolic activities are observed, depending on the cell type. To investigate the control of peroxisomal activity in connection with cell differentiation, we constructed hybrids between two types of cells whose histogenetic origins dictate significant differences in peroxisomal activities: hepatoma cells and fibroblasts, with high and low expression, respectively, of peroxisomal functions. In these hybrids, extinction of the elevated activities that characterize liver cells is observed, in parallel with the well-documented extinction of differentiated functions. This suggests the existence in fibroblasts of a negative trans-acting regulation.

[Lobular carcinoma in situ: the mammographic aspects and the therapeutic problems]

Lobular carcinoma in situ is an uncommon noninvasive breast neoplasm; it accounts for about 0.8-3.8% of breast cancers and presents 3 peculiar characteristics: multicentricity (60-90%), bilaterality (35-59%), and the risk of invasive cancer (17-37%). The latter feature led some authors to consider this lesion as a marker of the development of an invasive cancer rather than a real malignant neoplasm. The main problem after histologic diagnosis is the choice of treatment: follow-up or surgery? Some authors reported, in the patients with lobular carcinoma in situ, the same incidence of ipsilateral invasive carcinoma as that in the normal population, which suggests a "wait and see" policy. This study, carried out on 27 patients (mean age: 49 years) with histologic diagnosis of lobular carcinoma in situ yielded the following aspecific mammographic findings: clustered microcalcifications; stellate masses and irregular nodular lesions with or without calcifications; architectural distortion with calcifications. In 10 surgical patients, 2 ductal carcinomas were demonstrated near the lobular carcinoma in situ. In the 17 patients submitted to follow-up, lobular carcinoma in situ recurrences were found in 4 patients at biopsy; a comedocarcinoma associated with a metastatic axillary node was found in one patient. Thus, we conclude that, in the patients with lobular carcinoma in situ, a "wait and see" policy of close observation should be adopted.

Translocation (3;3) in a patient with thrombocytopenia and erythroid dysplasia

We describe a case with a translocation between the two chromosomes 3 with breakpoints q21 and q26, associated with a unique constellation of hematologic abnormalities. Megakaryocytic dysplasia and peripheral thrombocytosis are the most common abnormalities associated with this chromosome abnormality. Our patient had acute myeloid leukemia (AML), thrombocytopenia, dyserythropoiesis, and an increased myeloid/erythroid ration but no mekakaryocytic dysplasia. Although multilineage involvement has been reported, erythrocyte dysplasia associated with thrombocytopenia and without megakaryocyte dysplasia appears to be extremely rare. Our case supports the speculation that #3 abnormalities with breakpoints q21 and q26 affect a pluripotent stem cell and suggests that megakaryocytic involvement may not be pathognomonic in hematologic abnormalities with t(3;3)(q21;26).

Hypertriglyceridemia and hyperinsulinemia are potent inducers of endothelin-1 release in humans

The purpose of the study was to evaluate fasting endothelin-1 levels in subjects with syndrome X, in subjects with insulinoma, and in normal subjects. The single and synergistic contributions of insulin and triglyceride levels to endothelin-1 release were studied in normal subjects. This was achieved by the evaluation of endothelin-1 levels in response to an insulin bolus combined with a euglycemic clamp (protocol A) and during intralipid (test 1) or saline (test 2) infusions lasting 360 min (protocol B). In protocol B, a euglycemic two-step hyperinsulinemic (25 and 125 mU x kg-1 x h-1) clamp was started at 120 min. Subjects with syndrome X showed significantly higher endothelin-1 levels than normal subjects and subjects with insulinoma (7.22 +/- 0.89 vs. 2.61 +/- 0.38 and 2.49 +/- 0.24 pg/ml, P < 0.01). After an insulin bolus, endothelin-1 levels peaked at 10 min (3.71 +/- 0.96 pg/ml). The incremental area of endothelin-1 was significantly higher after insulin than after a saline bolus. In test 1, an acute increase in triglyceride levels significantly enhanced endothelin-1 levels, with were further increased by the synergistic contribution of high insulin and triglyceride levels. In test 2, endothelin-1 release was achieved at high insulin levels but remained significantly lower than in test 1. In conclusion, subjects with syndrome X showed higher endothelin-1 levels than normal subjects and subjects with insulinoma. These levels were reproduced in normal subjects by a simultaneous increase in insulin and triglyceride levels.

Sinus skeletonization: a treatment for dural arteriovenous malformations of the tentorial apex. Report of two cases

Two cases of dural arteriovenous malformation of the tentorial apex are presented. Both were treated surgically by means of a sinus skeletonization technique. The operative technique included a combined bioccipital and median suboccipital craniotomy in which the posterior third of the superior sagittal and the straight and bilateral transverse sinuses were skeletonized by incising the falx and the tentorium along the sinuses. Endovascular embolization was used prior to the surgical approach in one case. Clinical and angiographic cure was achieved in both patients, with a follow up of 4 years in the first case and 1 year in the second one. The surgical technique is described in detail.

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.

Asymptomatic cerebral infarctions in patients with ischemic stroke

We studied 383 consecutive patients with stroke and ischemic lesions on CT scan for the presence of symptomatic cerebral infarction (SCI) and asymptomatic cerebral infarction (ACI). We evaluated risk factors as well as volume, site and number of the lesions. ACIs occurred in 34% of the cases (130/383); 88% of ACIs were lacunes and internal borderzone infarctions, with a volume of less than 2 ml. Larger infarctions were asymptomatic in 27 patients (20.8%); 114 (68.7%) out of 166 patients with two or more SCIs (68.7%) had one or more ACIs. Infarctions in the lateral middle cerebral artery (MCA) territory were SCIs, in the medial MCA territory ACIs. Independent risk factors for ACI were age above 70 years and smoking; cardioembolism prevailed in SCI, small vessel disease in ACI; high levels of disability prevailed in SCIs.

Effects of an acute decrease in non-esterified fatty acid levels on muscle glucose utilization and forearm indirect calorimetry in lean NIDDM patients

The aim of the study was to evaluate an acute decrease in NEFA levels during an oral glucose tolerance test and its effects on glucose tolerance, muscle glucose uptake and muscle indirect calorimetry in ten lean non-insulin-dependent diabetic subjects. Two 75-g oral glucose tolerance tests were performed in random order. Placebo or 250 mg acipimox (to inhibit lipolysis) were administered orally 2 h before the start of the oral glucose tolerance test. Two hours after acipimox administration (time 0), non-esterified fatty acid, glycerol and 3-hydroxybutyrate levels decreased by 84, 68 and 77% respectively, compared to basal levels. Concomitantly, muscle lipid oxidation and non-oxidative glycolysis also decreased significantly. After placebo administration, non-esterified fatty acids, glycerol and 3-hydroxybutyrate and lipid oxidation increased by 29, 28, 106 and 33%, respectively (NS vs basal levels; p < 0.001 vs acipimox). There was a negative rate of net glucose storage (interpreted as glycogenolysis) during post-absorptive conditions and at time 0 after administration of both drugs. After oral glucose tolerance test, the incremental areas of blood glucose and insulin were significantly decreased by 18 and 19% after acipimox compared to placebo. In addition, the ratio between the incremental area of forearm muscle glucose uptake and the insulin levels was significantly increased by 45% during acipimox compared to placebo administration. Glucose oxidation and non-oxidative glycolysis were significantly higher while lipid oxidation was significantly lower after acipimox than after placebo. In conclusion, our study found that in lean non-insulin-dependent diabetic subjects, an acute decrease in non-esterified fatty acid levels improves glucose tolerance, muscle glucose uptake, glucose oxidation and non-oxidative glycolysis, but is unable to normalize glucose storage.

Left-ventricular outflow tract obstruction by mitral valve ring calcification and proximal septal hypertrophy in elderly patients. Presentation of 2 clinical cases

The pathophysiology, clinical presentation and prognosis of left-ventricular obstruction still represent an important cardiological problem. Various anatomical and/or functional mechanisms can cause this phenomenon. This report concerns 2 patients over 75 years old in whom the simultaneous presence of localized proximal septal hypertrophy and massive calcification in the anterior portion of the mitral valve ring provoked significant systolic intraventricular gradients. Cardiac rhythm disturbances and consequent variability of R-R intervals, found in both subjects, appear fundamental in determining the value of such gradients. Occasionally an anterior mitral ring calcification may bring about left-ventricular outflow tract obstruction in aged hearts where localized hypertrophy of the proximal portion of the intraventricular septum is present.

Plasma from patients exposed to ischemia reperfusion contains clastogenic factors and stimulates the chemiluminescence response of normal leukocytes

Clastogenic factors (CFs) are released by cells exposed to superoxide radicals and are found in various situations of oxidative stress. Certain of their components stimulate further superoxide production by competent cells, as shown with cytochrome c assay in previous work. In the present study, we report CF formation after ischemia reperfusion in patients undergoing coronary bypass surgery. Plasma ultrafiltrates, collected 20 min after reperfusion, had clastogenic properties in contrast to those collected before ischemia. We also show that the luminol-enhanced chemiluminescence response of neutrophils from healthy persons is increased when these cells are exposed to CF-containing postreperfusion samples from patients. Light emission was reduced to control values in the presence of superoxide dismutase. The burst of oxyradicals upon reperfusion is probably the initiating event of CF formation, which in turn leads to further oxyradical generation. This amplification process may explain why detectable levels of CF need a delay of at least 10 min. The activated state of neutrophils in ischemia reperfusion is at once a consequence and a source of CFs. Individual variation in the persistence of this clastogenic and leukocyte-activating material was observed. Therefore, antioxidants for prevention of ischemia reperfusion injury should be continued during the postoperative course.

Activation of cyclic nucleotide phosphodiesterases in FRTL-5 thyroid cells expressing a constitutively active Gs alpha

The expression of a constitutively activated Gs alpha protein in the rat thyroid cell line FRTL-5 causes an increase in the hormone-independent adenylyl cyclase activity and promotes TSH-independent growth of the cells. In spite of the constitutive activation of the adenylyl cyclase, the basal cAMP levels in these cells are only marginally increased. To define the role of phosphodiesterases (PDEs) in the genesis of this phenotype, cyclic nucleotide hydrolysis was determined in two cell lines expressing a mutated Gs alpha (Q227L). In these cells, the hydrolysis of both cAMP and cGMP was markedly increased in comparison with normal cells. This increase is the result of the activation of different forms of PDEs. Analysis of the cGMP hydrolysis and Ca++/calmodulin stimulation of the PDE activity indicated that the activity of a Ca++/calmodulin-stimulated PDE is increased in both cell lines. In addition, an increase in high-affinity, rolipram-sensitive cAMP-PDE activity was associated in both cell lines with the appearance of a 67-68 kilodalton (kDa) protein that cross-reacts with two antibodies against cAMP-PDEs. This form had the properties of ratPDE3.2/PDE4D2, a cAMP-PDE that is inducible by TSH in wild type cells. That an increase in cAMP-specific, rolipram-sensitive PDE plays a role in the phenotype induced by Q227L Gs alpha was confirmed by measurements of the mitogenic activity. Incubation with rolipram, which had no effect on wild type cells, caused an increase in cAMP levels and further stimulated TSH-independent proliferation in both cell lines carrying the mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation and selective inhibition of a cyclic AMP-specific phosphodiesterase, PDE-4D3

Prostaglandin E2 produces a transient increase in the intracellular concentration of cAMP in a human promonocytic cell line (U937). The temporal pattern consists of a rapid increase followed by a gradual decline to a new steady state. The decline phase coincides with an increase in the activity of a high affinity form of cAMP phosphodiesterase (PDE). Immunoprecipitation with specific antibodies revealed that the activated enzyme is a variant of PDE-4D. To confirm this observation, three isoforms of human PDE-4 (A, B, and D) were cloned and expressed in Sf9 cells with recombinant baculovirus infection. The activity of only one of the isoforms (PDE-4D3) increased after incubation with the catalytic subunit of protein kinase A and Mg-ATP. Hydrolytic activity of human PDE-4D3 was dependent on Mg2+. Before phosphorylation, the concentration-response curve for Mg2+ was biphasic and ranged from 0.1 to 100 mM. Phosphorylation of PDE-4D3 by protein kinase A produced a monophasic Mg2+ response curve (0.5 Vmax = 0.2 mM). Phosphorylation of PDE-4D3 increased the sensitivity of the enzyme to inhibition by RS-25344 (approximately 100-fold) and RS-33793 (approximately 330-fold). Thus, phosphorylation of PDE-4D3 induces an apparent conformation change that increases maximum velocity and sensitivity to inhibition by some analogues of nitraquazone. These observations provide the basis for a novel pharmacological strategy that targets an activated form of PDE in human leukocytes. Selective PDE-4D3 inhibitors may have useful anti-inflammatory properties with fewer adverse side effects than other PDE-4 inhibitors.

Spontaneous involution of optic pathway lesions in neurofibromatosis type 1: serial contrast MR evaluation

PURPOSE

To evaluate with contrast MR the evolution in size, signal, and contrast enhancement of optic pathway lesions in four patients with neurofibromatosis type 1.

METHODS

The four reported patients are children with ages ranging from 21 months to 13 years affected by neurofibromatosis type 1 and optic pathway lesions. No treatment of the optic pathway lesions was carried out in these patients. They have been followed by serial contrast MR.

RESULTS

In all patients a change in size, signal, and enhancement of optic pathways lesions was noted with time, and in the last follow-up study a marked reduction in size and enhancement of optic pathway lesions was observed in all cases.

CONCLUSIONS

Modification and regression of optic pathway lesions with spontaneous disappearance of the enhancement is demonstrated. This finding could have a crucial influence on the therapeutic approach of the optic pathway lesions.

Screening of umbilical cord blood hemoglobins by isoelectric focusing in capillaries

Separation and quantitation of the three main hemoglobin components of umbilical cord blood (fetal, acetylated fetal and adult hemoglobins; Hb F, Fac, A) by capillary isoelectric focusing (IEF) in a pH 6-8 gradient is reported. Even in coated capillaries (with covalently bound chains of linear acrylamido derivatives, notably N-acryloylaminoethoxyethanol), no base line separation is obtained between Hb F and A, although this is routinely achieved in gel slab IEF. However, when the carrier ampholyte buffers were added to 3% short-chain liquid linear polyacrylamide, base line resolution and stabilization of peak transit times were obtained. This suggests that even in the best coating procedures, patches of the inner capillary surface could still be naked, so that the static coating is complemented by a dynamic coating on the unoccupied sites. An additional improvement in separation occurs if the above mixture, comprising 5% carrier ampholytes in the pH 6-8 range and 3% soluble polyacrylamide, is made to contain 50 mM beta-alanine, a "separator" known to flatten the pH gradient around pH 7. In the normal newborns analyzed (n = 30), the following average values were obtained: Hb F, 70.1% (range 65-75%); Hb A, 20.2% (range 15-25%); and HbFac, 9.5% (range 7-11%).

Characterization of a hormone-inducible, high affinity adenosine 3'-5'-cyclic monophosphate phosphodiesterase from the rat Sertoli cell

In previous reports we have shown that FSH and beta-adrenergic agonists regulate the levels of mRNA and increase the activity of a high affinity cAMP phosphodiesterase (cAMP-PDE) in the immature rat Sertoli cell in culture. To identify and characterize the hormone-inducible form(s), the cAMP-PDE activity of the Sertoli cell was partially purified and its properties were determined using biochemical and immunological tools. The cAMP-PDE activity present in the 100,000g supernatant of Sertoli cell extracts was purified more than 2000-fold by four HPLC chromatographic steps. The major purified form of cAMP-PDE had a specific activity of 1-2 mumol/(min.mg of protein). Polyacrylamide gel electrophoresis and silver staining analysis showed that a 67-68 kDa polypeptide comigrated with the major peak of cAMP hydrolytic activity. The molecular weight of the crude or purified enzyme determined by gel filtration and sucrose density gradients was 150,000, suggesting that the native enzyme is an oligomeric structure. This PDE hydrolyzed cAMP with a Km of 1.97 +/- 0.26 microM. The hydrolysis of cAMP was neither inhibited nor stimulated by cGMP concentrations lower than 50 microM. Cyclic nucleotide catalysis required Mg2+, but was insensitive to Ca2+. The activity of this form was competitively inhibited by several inhibitors with the following potency: rolipram > RO 20-1724 > methylisobutylxanthine > cilostamide = milrinone. Because mRNAs derived from two distinct PDE4B and PDE4D genes are present in the Sertoli cell, selective and nonselective PDE antibodies were used to determine the origin of the inducible PDE protein.(ABSTRACT TRUNCATED AT 250 WORDS)

[Spontaneous transmural rupture of the esophagus (Boerhaave's syndrome)]

A case is presented of spontaneous transmural rupture of the lower third of the esophagus, penetrating the left pleural space. The patient underwent repair under 7 hours by combined approach (laparotomy and left thoracotomy). High mortality and morbidity of Boerhaave's syndrome can be lowered by prompt and careful evaluation of symptoms and radiological signs, so avoiding incorrect or late diagnosis. Results appear to be related more to the time interval between perforation and operation than to the specific technique used.