Collection of Ph-negative progenitor cells from Ph+ CML patients in complete cytogenetic remission after long-term interferon-alpha therapy.
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Adult↗
Biomedical subjects
L Marin
Publications and source records attributed to L Marin.
All-trans retinoic acid (ATRA) potentiates the in vitro inhibitory effects of IFN-alpha in parental (32D) and p210-bcr/abl transfected (LG7) murine myeloid cell lines.
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Animals↗
Determination of NA gene frequencies in the Spanish population by polymerase chain reaction with sequence-specific primers.
The granulocytic antigens NA1 and NA2 are two allelic gene products of the FcgammaRIIIB gene. These antigens are frequently targets of granulocytic-specific allo-antibodies and auto-antibodies that cause neutropenias. Different distributions of these antigens have been found in population studies. In our study, the genomic DNA of 345 healthy, unrelated Spanish individuals was typed for NA1 and NA2 using polymerase chain reaction (PCR) with sequence-specific primers (SSP). The gene frequencies found in the Spanish population were 0.29 for NA1 and 0.71 fo NA2. Flow cytometry immunotyping was also carried out in 20 of these samples, and an exact correlation was observed among the results. The gene frequencies determined in our study are similar to those reported in other Caucasian populations. The null phenotype reported in other serological studies was not found. This typing system can be used in population studies instead of serological tests as a more rapid, simple and reproducible method.
Flow Cytometry↗
Repression of hybrid dysgenesis in Drosophila melanogaster by combinations of telomeric P-element reporters and naturally occurring P elements.
In Drosophila melanogaster, hybrid dysgenesis occurs in the germline of flies produced by crosses between females lacking P elements and males carrying 25-55 P elements. We have previously shown that a complete maternally inherited repression of P transposition in the germline (P cytotype) can be elicited by only two autonomous P elements located at the X chromosome telomere (cytological site 1A). We have tested whether P transgenes at 1A, unable to code for a P-repressor, may contribute to the repression of P elements. Females carrying a P-lacZ transgene at 1A ["P-lacZ(1A)"], crossed with P males, do not repress dysgenic sterility in their progeny. However, these P-lacZ(1A) insertions, maternally or paternally inherited, contribute to P-element repression when they are combined with other regulatory P elements. This combination effect is not seen when the P-lacZ transgene is located in pericentromeric heterochromatin or in euchromatin; however a P-w,ry transgene located at the 3R chromosome telomere exhibits the combination effect. The combination effect with the P-lacZ(1A) transgene is impaired by a mutant Su(var)205 allele known to impair the repression ability of the autonomous P elements at 1A. We hypothesized that the combination effect is due to modification of the chromatin structure or nuclear location of genomic P elements.
Animals↗
Combined therapy with Fludarabine and cyclophosphamide in relapsed/resistant patients with B-cell chronic lymphocytic leukaemia and non-Hodgkin's lymphomas.
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Adult↗
Synaptic physiology and mitochondrial function in crayfish tonic and phasic motor neurons.
Phasic and tonic motor neurons of crustaceans differ strikingly in their junctional synaptic physiology. Tonic neurons generally produce small excitatory postsynaptic potentials (EPSPs) that facilitate strongly as stimulation frequency is increased, and normally show no synaptic depression. In contrast, phasic neurons produce relatively large EPSPs with weak frequency facilitation and pronounced depression. We addressed the hypothesis that mitochondrial function is an important determinant of the features of synaptic transmission in these neurons. Mitochondrial fluorescence was measured with confocal microscopy in phasic and tonic axons and terminals of abdominal and leg muscles after exposure to supravital mitochondrial fluorochromes, rhodamine-123 (Rh123) and 4-diethylaminostyryl-N-methylpyridinium iodide (4-Di-2-Asp). Mitochondria of tonic axons and neuromuscular junctions had significantly higher mean Rh123 and 4-Di-2-Asp fluorescence than in phasic neurons, indicating more accumulation of the fluorochromes. Mitochondrial membrane potential, which is responsible for Rh123 uptake and is related to mitochondrial oxidative activity (the production of ATP by oxidation of metabolic substrates), is likely higher in tonic axons. Electron microscopy showed that tonic axons contain approximately fivefold more mitochondria per microm2 cross-sectional area than phasic axons. Neuromuscular junctions of tonic axons also have a much higher mitochondrial content than those of phasic axons. We tested the hypothesis that synaptic fatigue resistance is dependent on mitochondrial function in crayfish motor axons. Impairment of mitochondrial function by uncouplers of oxidative phosphorylation, dinitrophenol or carbonyl cyanide m-chlorophenylhydrazone, or by the electron transport inhibitor sodium azide, led to marked synaptic depression of a tonic axon and accelerated depression of a phasic axon during maintained stimulation. Iodoacetate, an inhibitor of glycolysis, and chloramphenicol, a mitochondrial protein synthesis inhibitor, had no significant effects on either mitochondrial fluorescence or synaptic depression in tonic or phasic axons. Collectively, the results provide evidence that mitochondrial oxidative metabolism is important for sustaining synaptic transmission during maintained stimulation of tonic and phasic motor neurons. Tonic neurons have a higher mitochondrial content and greater oxidative activity; these features are correlated with their greater resistance to synaptic depression. Conversely, phasic neurons have a lower mitochondrial content, less oxidative activity, and greater synaptic fatigability.
Abdomen↗
Quantal release at visualized terminals of a crayfish motor axon: intraterminal and regional differences.
Synaptic transmission was measured at visualized terminal varicosities of the motor axon providing the sole excitatory innervation of the "opener" muscle in walking legs of crayfish (Procambarus clarkii Girard). Two questions were addressed: 1) How uniform is quantal emission at different locations along terminals innervating a single muscle fiber, and 2) can differences in quantal emission account for the different excitatory postsynaptic potential (EPSP) amplitudes generated by terminals localized in defined regions of the muscle? Extracellular "macropatch" electrodes were placed over individual varicosities, viewed after brief exposure to a fluorescent dye, and synaptic currents were recorded to determine quantal content of transmission. Along terminals supplying a single muscle fiber, nonuniform release was found: Varicosities closer to the point of origin of the terminal branch released more transmitter than those located more distally. Quantal content was higher for varicosities of the muscle's proximal region (where large EPSPs occur) than for varicosities of the central region (where small EPSPs occur). The probability of transmitter release per synapse is estimated to be greater for the proximal varicosities. At low frequencies of stimulation, quantal content per muscle fiber is two to four times larger in the proximal region. Taken in conjunction with a twofold higher mean input resistance for the proximal muscle fibers, the difference in quantal content can account for a four- to eightfold difference in EPSP amplitude. The observed mean EPSP amplitude is at least eight times larger in the proximal region. We discuss factors contributing to differences in EPSP amplitudes.
Animals↗
Biochemical and pharmacological characterization of cannabinoid binding sites using [3H]SR141716A.
This study describes the binding characteristics of cannabinoid binding sites expressed in rat cerebellar membranes using the tritiated derivative of SR141716A, the newly described cannabinoid receptor antagonist. A single population of high-affinity binding sites (K(D) = 0.59 +/- 0.08 nM; Bmax = 3.86 +/- 0.42 pmol mg-1 of protein) was demonstrated. Kinetic, competition and saturation experiments give similar results in terms of SR141716A affinity. delta 9-tetrahydrocannabinol and the 11-hydroxy derivative competitively inhibited the specific binding of [3H]SR141716A (Ki = 47 +/- 9 and 32 +/- 4 nM, respectively). The cannabinoid agonist WIN55212-2 has a 25-fold lower affinity for [3H]SR141716A than for [3H]WIN55212-2, showing that the two ligands do not recognize the cannabinoid binding site in the same fashion.
Analgesics↗
Evidence for a vitamin D paracrine system regulating maturation of developing rat lung epithelium.
Rat fetal lung is a target tissue for 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25 (OH)2 D3]. We have identified the cells that respond to the hormone and tested the hypothesis that the lung is also a source of 1 alpha,25(OH)2D3. We found that 1) at the end of pregnancy (days 20-21) alveolar type II cells (ATII) bore 1 alpha,25(OH)2D3 receptors and responded to the hormone. Incubating these cells with 10(-9) M 1 alpha,25(OH)2D3 for 48 h stimulated the synthesis (87.3 +/- 9.1%) and release (61.7 +/- 6.1%) of disaturated phosphatidylcholine; 2) EB-1213, a 1 alpha,25(OH)2D3 analogue with low calcemic activity, had similar effects on ATII; 3) neither fetal lung fibroblasts nor neonatal ATII (day 2 postpartum) expressed 1 alpha,25(OH)2D3 receptors; and 4) in contrast, fetal lung fibroblasts taken on days 19-22 of gestation converted [3H]25(OH)D3 to [3H]1 alpha,25(OH)2D3, whereas ATII and skin fibroblasts did not. These findings suggest that 1 alpha,25(OH)2D3 is a local mediator of epithelial-mesenchymal cell interactions in the developing rat lung and that 1 alpha,25(OH)2D3 or EB-1213 might be therapeutically useful in treating the respiratory distress syndrome of premature neonates.
Animals↗
Diagnosis, management, and survival of patients with leptomeningeal cancer based on cerebrospinal fluid-flow status.
BACKGROUND: The authors assessed cerebrospinal fluid (CSF) flow in patients with carcinomatous meningitis using technetium-99m-DTPA (Tc-99) ventriculography to determine the frequency of flow abnormalities, their reversibility with treatment, and the implications for successful therapy and survival. METHODS: Technetium-99m-DTPA flow studies were performed in 31 patients after placement of Ommaya reservoirs (Baxter, McGaw Park, IL). Two millicuries of Tc-99 were injected into the reservoir. Planar images of the head and entire spine were obtained after 10 and 30 minutes and after 1, 4, 6, and 24 hours. Follow-up studies were performed for 12 patients whose initial studies were abnormal or who developed complications of therapy. RESULTS: In 19 of the 31 patients (61%), ventricular-outlet, spinal, or convexity blocks were identified. In 11 of these 19 patients, focal radiotherapy to the site of the block restored normal flow. Survival among patients with initially normal, abnormal but correctable, and abnormal but uncorrectable CSF flow differed significantly (6.9, 13.0, and 0.7 months respectively; P < 0.001). Some patients who were treated intrathecally despite abnormal CSF flow experienced drug-related toxicity. CONCLUSIONS: Cerebrospinal fluid-flow blocks are common in patients with carcinomatous meningitis and may occur at the skull base, in the spinal canal, and over the convexities. These flow abnormalities often can be corrected with appropriately directed radiotherapy. If untreated, CSF tumor progression (protected site effect), neurotoxicity (high concentration effect), and systemic toxicity (reservoir effect) can occur, resulting in shortened survival and treatment-related morbidity. Therefore, intrathecal chemotherapy should be preceded by a radionuclide flow study and should be delayed if abnormal flow is documented until appropriate radiotherapy reestablishes normal flow.
Adolescent↗
Synaptic differentiation of a single motor neuron: conjoint definition of transmitter release, presynaptic calcium signals, and ultrastructure.
The opener muscle in the walking legs of the crayfish (Procambarus clarkii) is innervated by only one excitatory motor neuron, yet excitatory postsynaptic potentials (EPSPs) of proximal fibers are eightfold larger than those of central muscle fibers at low frequencies of activation, due in large measure to differences in presynaptic properties. We investigated quantal release properties, calcium signals, and ultrastructure of presynaptic terminals to elucidate factors that could account for the physiological differences. Focal macropatch electrodes were placed over individual visualized terminal varicosities to obtain records of quantal contributions to the excitatory junctional current (EJC). At low frequencies of activation, mean quantal content is greater for proximal than for central varicosities. This difference is due to a higher probability of release per synapse, and not to a larger number of active synapses. Recorded varicosities were labeled with fluorescent beads deposited by the electrode. These beads adhered to the muscle fibers, outlining the recorded site for subsequent serial thin sectioning and reconstruction from electron micrographs. Comparisons of structure and function were made for individual varicosities. The number of active zones per terminal surface area and the number of synapses with multiple active zones (complex synapses) were greater in high-output varicosities. Calcium indicators were loaded into proximal and central nerve terminals by axonal injection to compare the relative differences in calcium buildup during stimulation. Presynaptic calcium signals were larger for proximal varicosities than for central varicosities.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Activity-induced changes in synaptic release sites at the crayfish neuromuscular junction.
Crustacean motor axons provide a model in which activity-dependent changes in synaptic physiology and synaptic structure can be concurrently observed in single identifiable neurons. In response to a train of stimulation, crustacean neuromuscular junctions undergo pronounced facilitation of transmitter release. The effects of maintained high-frequency stimulation may persist for at least several hours ("long-term facilitation"). Electrophysiological studies suggest that the number of "active" synapses contributing transmitter quanta at low frequencies of stimulation increases during and after a train of high-frequency stimulation. However, at different terminal recording sites the effect of stimulation varies, and it was observed that not all released quanta produce a voltage change in the postsynaptic muscle cell. Electron microscopic examinations of serial sections from nerve terminals subjected to stimulation were made to determine whether changes in synaptic structure could be correlated with activity-induced long-lasting enhancement of transmission. A procedure was introduced for marking a recorded terminal with fluorescent polystyrene microspheres, which are visible in electron micrographs of the recording site. Crustacean nerve terminals possess a large number of discrete synapses, a small fraction of which have multiple presynaptic "active zones" (dense bodies with clustered synaptic vesicles, thought to represent sites of evoked transmitter release). In terminals previously stimulated, the proportion of synapses with multiple "active zones" is greater than in control unstimulated terminals. Total synaptic vesicle counts and readily releasable vesicles at synapses are not significantly different in previously stimulated terminals and controls. In terminals fixed during stimulation a few synapses show evidence of division in "active zones," and synaptic vesicle counts are lower than in controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Maturational changes induced by 1 alpha,25-dihydroxyvitamin D3 in type II cells from fetal rat lung explants.
Specific binding sites for 1 alpha,25 dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] localized to type II pneumocytes have been evidenced in fetal rat lung at the end of gestation, suggesting a role for vitamin D3 in the control of lung maturation. In this study, we describe the morphological changes that occur in lung explants from 18-day-old rat fetuses grown for 1 and 2 days in control conditions and in the presence of 1 alpha,25(OH)2D3 (10(-9) M) or dexamethasone (10(-7) M). Point counting and planimetric measurements on light and electron micrographs show that 1 alpha,25-(OH)2D3 1) dramatically decreases the mean glycogen content of type II cell profiles between days 1 and 2 of the culture, suggesting an acceleration of the glycogenolytic processes normally occurring at that stage and 2) does not change the intracellular osmiophilic lamellar body (OLB) content of cell profiles, but increases the amount of intraluminal surfactant by 126% when expressed as surfactant clusters surface area/section surface area and by 129% when expressed on a per cell basis, suggesting a stimulation of surfactant synthesis and secretion. By contrast, dexamethasone increases the mean intracellular OLB content of type II cell profiles by 306% and decreases the relative surface area of secreted material by 53 and 73%. In conclusion, 1 alpha,25(OH)2D3 accelerates the physiological maturation of fetal rat type II pneumocytes and could represent a key factor for the onset of normal lung function at birth.
Animals↗
Variation in terminal morphology and presynaptic inhibition at crustacean neuromuscular junctions.
Synaptic terminals of excitatory and inhibitory neurons supplying muscle fibers in leg muscles of crabs (Pachygrapsus crassipes and Hyas areneus) were investigated with light and electron microscopy. Terminals responsible for large excitatory postsynaptic potentials (EPSPs) at low frequencies of activation had a compact configuration with clusters of terminal boutons radiating from the main axon branch. Terminals responsible for small EPSPs had a more diffuse organization, with boutons often arranged in series along thin axon branches. Inhibitory neurons, when activated, produced both presynaptic and postsynaptic inhibitory effects, with the former being more potent at low frequencies of activation. Presynaptic inhibition was variable in magnitude but was generally strong in fibers with large EPSPs. Representative terminals from regions of strong and weak presynaptic inhibition were identified by activity-dependent uptake of horseradish peroxidase, serially sectioned, and reconstructed from electron micrographs. Both regions were found to contain axo-axonal synapses from inhibitory to excitatory terminals, with a larger number in the region of strong presynaptic inhibition. In addition, axo-axonal synapses were more uniformly distributed in the latter region. The number of inhibitory presynaptic dense bars (active zones) was somewhat higher in the region of weak inhibition, but larger individual dense bars occurred in the region of strong inhibition. Possible factors contributing to the differences in strength of inhibition include: (1) morphology and electrical properties of terminals; and (2) high probability of transmission at a relatively small number of inhibitory synapses during low frequency activation in the region of strong inhibition.
Action Potentials↗
Oral rehydration therapy: studies on potassium balance.
The clinical response and changes in potassium balance were studied during oral rehydration therapy (ORT) with a solution containing 20 mmol potassium per litre in well-nourished and malnourished infants of 3 to 15 months of age as well as in neonates and young infants less than 2 months old (range 5-60 days). All infants were successfully rehydrated orally. The potassium intake considerably exceeded the potassium output in all groups during the entire rehydration period. The stool and urine potassium output were about the same in the 3 groups of patients. The retention of potassium increased during ORT in all groups at about the same rate. The study thus demonstrates that an oral rehydration solution (ORS) containing 20 mmol potassium per litre provides enough potassium to all patients. An increase in the potassium concentration of the ORT is therefore not recommended.
Feces↗
Relationships among surfactant fraction lipids, proteins and biophysical properties in the developing rat lung.
Lung development is associated with increases in specific phospholipids and proteins that function as critical pulmonary surfactant components. Attempts to characterize the pattern of surfactant development in fetal rat lungs have been hampered by the lack of a micromethod which will permit quantitative isolation of surface active components from small tissue specimens. As part of studies designed to elucidate the metabolic regulation of lung development in the rat, we developed sucrose density gradient centrifugation procedures to separate pulmonary phospholipids and proteins into a presumed surfactant (S) fraction and a residual (R) fraction. Electron microscopy of S pellets from mature fetuses identified predominant lamellar bodies and minimal contamination; incubation with 5 mM CaCl2 induced the appearance of tubular myelin figures, implying functional potential. This was confirmed by demonstrating low surface tension (less than 1 dyn/cm) in S, but not R, fractions at term gestation (21.5 days) and in 1-day-old neonatal lung isolates, based on dynamic measurements using the oscillating bubble technique. Surface activity was also high in the S pellets from fetuses at 20.5 days of gestation; however, at 19.5 days, minimum surface tension values of at least 19 dyne/cm were seen. These results correlated directly with biochemical analyses which indicated striking increases in three surfactant-associated proteins (SP-A, SP-B, and SP-C) after 19.5 days of gestation; a finding in agreement with previously reported data on the developmental increase of disaturated phosphatidylcholine in fetal rat lung. We conclude that isolation of S fraction components is valuable for demonstrating maturation of the fetal rat lung and may provide a useful tool for the study of regulatory mechanisms influencing surfactant production and function.
Animals↗
1,25(OH)2D3 stimulates phospholipid biosynthesis and surfactant release in fetal rat lung explants.
Lung tissue from 18-day-old rat fetuses was cultured in the presence of 1,25-dihydroxyvitamin D3 - 1,25(OH)2D3 - (10(-9) M) and dexamethasone (10(-7) M) for 48 h. 1,25(OH)2D3 increased the lung content in phospholipids more specifically related to lung surfactant, phosphatidylcholine and phosphatidylglycerol. This increase was similar to that observed with dexamethasone. In addition, unlike dexamethasone, 1,25(OH)2D3 stimulated the surfactant release into luminal spaces, as evidenced by light and electron microscopy. Thus, vitamin D3 might represent an additional factor controlling fetal lung maturation by stimulating phospholipid synthesis and surfactant release from type II cells.
Animals↗
Effects of the antiglucocorticoid RU 486 on the initiation of ultrastructural type-II cell differentiation in fetal rat lung.
The possible early role of endogenous glucocorticosteroids on the further ultra-structural development of the fetal rat lung epithelium was investigated in vitro using a potent antiglucocorticoid drug, RU 486. Lung primordia were explanted on day 13 of gestation and cultured for 4-6 days in the presence of fetal calf serum, with or without RU 486 in excess. The results obtained show that osmiophilic lamellar bodies specific for morphologically differentiated type-II cells did appear in a number of epithelial cells, even though the glucocorticosteroids possibly present in the culture medium, or transferred at explantation were antagonized by RU 486. The number of lamellar bodies stored in these pneumocytes was not different from that in controls. In contrast, their total surface area per cell profile was transiently decreased. Taken together the reported data strongly suggest that endogenous glucocorticosteroids are not necessary for the initiation of type-II cell differentiation.
Animals↗