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The seroprevalence of HTLV-1 was studied in parents, brothers, siblings and sexual partners of 147 patients with spastic paraparesis associated to HTLV-1 (HAM/TSP) and 84 patients with HTLV-1 negative spastic paraparesis (SP). Seroprevalence was 29.1% for HAM/SP and 0% for SP relatives (p < 0.001); the last figure is similar to that of the general population. Seroprevalence in sexual partners was 65%, suggesting that sexual intercourse is the principal route of transmission. Likewise, seroprevalence in siblings of mothers with HAM/TSP or HTLV-1 positive was 17.6%, suggesting a high maternal transmission.

Objective: We have studied the usefulness of squamous cell carcinoma antigen (SCC Ag) in diagnosis and prognosis of lung cancer (LC)., Material and Methods: We have measured the serum SCC Ag levels in 388 subjects: 69 healthy persons; 103 with nonmalignant lung diseases (NMLD); 24 with lung metastasis of extrapulmonary origin (LMEO); and 192 with LC (88, with squamous cell carcinoma [SCC] type). In 55 with SCC, we analyzed the survival time., Results: Serum SCC Ag was above 2.5 ng/ml in 1.4 percent of healthy persons; 2.9 percent of those with NMLD; 8.3 percent of those with LMEO; and 27.6 percent of those with LC. Such percentage was 47.7 percent in SCC. In this type, there were significant differences according to the extent of disease (61.6 percent in advanced stages, and 26.5 percent in localized stages, p = 0.002). In the other types, the sensitivity was substantially lower. The initial SCC Ag has prognostic significance (p = 0.02) in the univariate analysis, but it loses such significance in a multivariate model, including the stage., Conclusions: Therefore, we do not recommend this marker in the clinical management of patients with LC, even it can be useful in the differential diagnosis if used in combination with other markers.

A low conductance calcium-activated K+ channel is thought to regulate the rate of firing of several excitable cells. In skeletal muscle the expression of this channel is under nerve control. Previously, we reported that axonal flow blockade of rat nerves, induced by colchicine, caused a transient increase in muscle apamin receptors, determined by 125I-apamin binding to membrane fractions. The increase in apamin receptors was correlated with repetitive discharges resembling myotonic potentials in the electromyogram, that were blockable by apamin. Here we show that the increase in muscle apamin receptors and the alteration of the electromyogram are followed closely by a slowing of the twitch relaxation, that in turn, is decreased by apamin. Furthermore, the presence of myotonic-like alterations in the electromyogram and a slowing of muscle relaxation when muscle apamin receptors are increased suggests that these channels may participate, among other factors, in the generation of some kinds of myotonia.

Microcin E492, a polypeptide antibiotic, has been shown to have an M(r) of 6,000 by urea-SDS-polyacrylamide gel electrophoresis of the fluorescently labelled compound. It is known that the bactericidal action of microcin involves a loss of the transmembrane potential. In this study we show that microcin forms cation-selective channels in planar phospholipid bilayers. The channels have two main conductance states the current-voltage curves of which rectify. The reversal potentials measured under biionic conditions indicate a permeability sequence of NH4+ > K+ = Rb+ = Cs+ > Na+ = Na+ = Li+ > Tris+. The results suggest that membrane potential dissipation induced by microcin is a consequence of the formation of pores in the bacterial membrane.

We have shown an increase of apamin receptors in rat skeletal muscle membranes following the application of colchicine to the sciatic nerve. 125I-apamin binding to partially purified membrane fractions was observed since day 4, reached a maximum around days 6-15, and was negligible at day 35 after the application of colchicine. Control muscles (nerves treated with buffer solution) showed low binding values (11 fmol/mg protein). Maximal 125I-apamin binding values to partially purified muscle membranes of colchicine-treated rats (42 fmol/mg protein) were lower than those obtained in denervated muscle (95 fmol/mg protein). The affinity binding constant values were 37 (colchicine) and 95 pM (denervation). No signs of muscle denervation were observed on histological examination of the nerve submitted to colchicine treatment nor in the muscles innervated by it. Muscle tension developed by indirect stimulation was the same as in controls. We here show also that partially purified membranes of normal untreated muscles have measurable amounts of 125I-apamin binding (13 fmol/mg protein), similar to those obtained in control muscles. Electromyographic recordings of the muscles after colchicine treatment of the nerve showed abnormal repetitive electrical discharges, similar to myotonic discharges, that were present with a similar temporal course as the increase in apamin receptors. The myotonic-like discharges were suppressed by the topical application of apamin to the muscle, whereas the toxin had no effect on anthracene-9-carbolytic acid-induced myotonia. Our results suggest that a neurotrophic factor that travels by axonal flow is involved in the regulation of the expression of apamin receptors in skeletal muscle membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

The identity of the second messenger that directly activates the light-dependent conductance in invertebrate photoreceptors remains unclear; the available evidence provides some support for cGMP and Ca2+. To resolve this issue we have applied these second messengers to membrane patches excised from the light-sensitive lobe of Limulus ventral photoreceptors. Our results show that these patches contain channels that can be opened by cGMP, but not by Ca2+. These cGMP-activated channels closely resemble the channels activated by light in cell-attached patches. This evidence suggests that cGMP is the messenger that opens the light-dependent channel in invertebrate photoreceptors.

The properties of light-dependent channels in Limulus ventral photoreceptors have been studied in cell-attached patches. Two sizes of single-channel events are seen during illumination. Previous work has characterized the large (40 pS) events; the goal of the current work was to characterize the small (15 pS) events and determine their relationship to the large events. The small events are activated by light rather than as a secondary result of the change in membrane voltage during light. The mean open time of the small events is 1.34 +/- 0.49 ms (mean +/- SD, n = 15), approximately 50% of that of the large events. The large and small events have the same reversal potential and a similar dependence of open-state probability on voltage. Evidence that these events are due to different conductance states of the same channel comes from analysis of relatively infrequent events showing a direct transition between the 15 and 40-pS levels. Furthermore, large and small events do not superpose, even at positive voltages when the probability of being open is very high, as would be predicted if the two-sized events were due to independent channels. Expression of the different conductance states is not random; during steady illumination there are alternating periods of several hundred milliseconds in which there are consecutive, sequential large events followed by periods in which there are consecutive, sequential small events. At early times during the response to a step of light, the large conductance state is preferentially expressed. At later times, there is an increase in the relative contribution of the low conductance state. These findings indicate that there is a process that changes the preferred conductance state of the channel. This alteration has functional importance in the process of light adaptation.

Probes pRepHind, Rep20, p242B1-1, pPF-14, clone 26 and 34 were compared for their applicability to detect P. falciparum in field conditions. Ninety four clinical samples from patients living in the malaria endemic area of Tumaco (Pacific Coast) plus 88 from Villavicencio (Eastern Plains) were tested in "dotblot" hybridization experiments. Probes Rep20, p242B1-1, pRepHind and pPF-14 detected up to 17 pg of purified P. falciparum DNA, while clone 26 and clone 34 detected up to 425 pg DNA. Probes pPF-14, P242B1-1, pRepHind and Rep 20 exhibited comparable detection levels of parasites in infected blood samples. Sensitivity declined from 69-94% in subjects with parasitemias higher than 10.000 par./ul to 15-42% in subjects with parasitemias lower than 100 par./ul. pPF-14 and p24B1-1 showed the highest sensitivity, while clone 26 and 34 presented significantly lower sensitivities. All probes were shown to be highly specific. Detection levels are dependent on specimen treatment. Treatment consisting of serum removal, Triton X-100 lysis, Proteinase K digestion, Phenol and Chloroform extractions followed by Ethanol precipitation yielded 100% sensitivity for specimens with parasite density higher than 1,000 par./l.

A 54-year-old man was receiving calcium dobesilate for retinopathy and after 8 days he presented fever of more than 39 degrees C, generalized myalgia, chills and headache. Other causes of fever were ruled out. A challenge test was done with a single therapeutic oral dose of calcium dobesilate and fever appeared 20 h later and lasted 8 h. Our patient fulfils Young's stringent criteria for drug fever. To our knowledge drug-induced fever due to calcium dobesilate has not been reported previously.

The interaction of Ca2+ and Ba2+ with a Ca2+-activated K+ channel from rabbit skeletal muscle membranes is studied in planar lipid bilayers. At [Ca2+] greater than or equal to 100 microM in the cis side (the side to which the vesicles are added) and at positive voltages, the channel kinetics consisted of bursts of activity interrupted by long periods of quiescence. We found that the reciprocal of the mean burst time increases linearly with [Ca2+], whereas the mean time for the quiescent (closed) periods is independent of [Ca2+]. The number of quiescent periods is reduced by increasing [K+]. Micromolar amounts of cis Ba2+ do not activate the channel, but induce similar "slow" closings. Also, in this case, the mean burst time is inversely proportional to the [Ba2+] and the mean closed time is independent of [Ba2+]. Raising [K+] either symmetrically or only in the trans side relieved the Ba2+ effect. trans Ba2+ also induces changes in the slow kinetics, but in millimolar amounts. These results suggest that the quiescent periods correspond to a channel blocked by a Ba ion. The voltage dependence of the cis blockade indicates that the Ba2+ binding site is past the middle of the membrane field. The similarities in the slow kinetics induced by Ca2+ and Ba2+ suggest that Ca2+ blocks the channel by binding to the same site. However, binding of Ca2+ to the site is 10(5)-fold weaker.

A new method for isolating transverse tubule membranes from rabbit skeletal muscle has been developed. This procedure has the advantage of being mild, fast, and producing with good yields a purified membrane fraction. The transverse tubule membranes are purified by a discontinuous sucrose density centrifugation after loading contaminating light sarcoplasmic reticulum vesicles with calcium phosphate in the presence of ATP. Immunofluorescence staining of cryostat sections of rabbit psoas muscle with purified goat antibodies directed against the purified membranes shows that the reacting antigens are distributed at the boundary of the A and I bands of the myofibrils where transverse tubules are localized in mammalian muscle. The purified antibodies showed no cross-reactivity with sarcoplasmic reticulum, nor did they show any fluorescence staining of the muscle plasma membrane, indicating that the isolated membranes indeed originate from the transverse tubules. The transverse tubule fraction has a characteristic protein composition distinguishable from that of sarcoplasmic reticulum, a much higher cholesterol content than that of the crude microsomes, plasma membrane, and sarcoplasmic reticulum, and a phospholipid content about twice as high as that of sarcoplasmic reticulum and plasma membrane. The purified transverse tubule membrane has a distinct phospholipid composition with high contents of sphingomyelin and phosphatidylserine. A Mg2+-activated ATPase characteristic of the transverse tubule fraction undergoes a 20-30-fold increase in specific activity during purification. The levels of Ca2+-ATPase activity present in the purified transverse tubule fraction remain comparable to those of sarcoplasmic reticulum even after extensive removal of the latter.

Limited labeling of amino groups with fluorescamine in fragmented sarcoplasmic reticulum vesicles inhibits Ca2+-ATPase activity and Ca2+ transport. Under the labeling conditions used, 80% of the label reacts with phosphatidylethanolamine and 20% with the Ca2+-ATPase polypeptide. This degree of labeling does not result in vesicular disruption or in loss of vesicular proteins and does not increase the membrane permeability to Ca2+. Fluorescamine labeling of a purified Ca2+-ATPase devoid of aminophospholipids also inhibits Ca2+-ATPase activity, suggesting that labeling of lysine residues of the enzyme polypeptide is responsible for the inhibition of Ca2+-ATPase activity in sarcoplasmic reticulum. Fluorescamine labeling interferes with phosphoenzyme formation and decomposition in both the native vesicles and the purified enzyme; addition of ATP during labeling, and with less effectiveness ADP or AMP, protects both partial reaction steps. Addition of a nonhydrolyzable ATP analog protects phosphoenzyme formation but not decomposition. The inhibition of Ca2+ transport but not of Ca2+-ATPase occurs in sarcoplasmic reticulum vesicles labeled in the presence of ATP, indicating that the transport reaction is uncoupled from the Ca2+-ATPase reaction. The inhibition of Ca2+ transport but not of Ca2+-ATPase activity is also found in sarcoplasmic reticulum vesicles in which only phosphatidylethanolamine has reacted with fluorescamine. Furthermore, the extent of labeling of phosphatidylethanolamine is correlated with the inhibition of Ca2+ transport rates. The inhibition of Ca2+ transport is a reflection of the inhibition of Ca2+ translocation and is not due to an increase in Ca2+ efflux. We propose that labeling of phosphatidylethanolamine perturbs the lipid environment around the enzyme, producing a specific defect in the Ca2+ translocation reaction.

Addition of membrane vesicles prepared from transverse tubule (T-tubule) membranes of rabbit skeletal muscle to the aqueous phase of a planar lipid bilayer induces a stepwise increase in conductance. This conductance is both voltage and Ca2+ dependent. At 1 mM Ca2+, the steady-state conductance is maximal at voltages higher than +20 mV and decreases for more negative voltages. (Voltages refer to the side to which the vesicles are added, cis) Decreasing the Ca2+ concentration reversibly shifts the conductance-voltage curve toward the right along the voltage axis. Furthermore, Ca2+ can activate the conductance only if added to the cis compartment. Neither Mg2+, Ba2+, nor Cd2+ can activate the conductance induced by T-tubule vesicles. Addition of 5 mM tetraethylammonium ion to the trans, but not the cis, side abolishes the T-tubule-induced conductance. The Ca2+-dependent conductance appears as a consequence of ionic channel formation. Single-channel activity appears in bursts followed by periods of time in which the channel remains "silent". The conductance of the open channel averages 226 pS in 0.1 M KC1 and is voltage and Ca2+ independent. However, the fraction of time that the channel remains in the open state is voltage and Ca2+ dependent in a manner that parallels the voltage and Ca2+ dependence of the multichannel membrane. The channel is 6.6 times more permeable to K+ than to Na+ and is impermeable to C1-.

The population of neurons and the neuronal size in the nucleus basalis of Meynert (nbM) were studied in 20 patients with definite Creutzfeldt-Jakob disease (CJD). When compared with a normal control group, the 20 CJD brains showed a significant loss of neurons and reduction of neuronal size, mainly in the middle level of the nbM and mostly affecting the right side. Since these findings show some parallelism with the amount of cortical damage and given the scarce gliosis and spongiosis found in only six of the 20 CJD brains, we postulate that the involvement of the nbM in CJD is a retrograde abnormality secondary to the damage of the neocortex.

A Ca-activated, K-selective channel from plasma membrane of rat skeletal muscle was studied in artificial lipid bilayers formed from either phosphatidylethanolamine (PE) or phosphatidylserine (PS). In PE, the single-channel conductance exhibited a complex dependence on symmetrical K+ concentration that could not be described by simple Michaelis-Menten saturation. At low K+ concentrations the channel conductance was higher in PS membranes, but approached the same conductance observed in PE above 0.4 m KCl. At the same Ca2+ concentration and voltage, the probability of channel opening was significantly greater in PS than PE. The differences in the conduction and gating, observed in the two lipids, can be explained by the negative surface charge of PS compared to the neutral PE membrane. Model calculations of the expected concentrations of K+ and Ca2+ at various distances from a PS membrane surface, using Gouy-Chapman-Stern theory, suggest that the K+-conduction and Ca2+-activation sites sense a similar fraction of the surface potential, equivalent to the local electrostatic potential at a distance of 9 A from the surface.

Normal human sera induce the formation of fat-containing cells (FCC) in human bone marrow cultures. A nearly complete monolayer of FCC is formed after 7-14 days of cultivation with 20% human sera in the medium. FCC-inducing activity (FCCIA) is nondialyzable through 14,900-dalton cutoff membrane and is stable at 56 degrees C for 30 min. Abundant FCCIA was found in 83% of normal human sera but in only 20% of sera from untreated patients with different hemopoietic disorders and in 32% of treated leukemic patients. It is suggested that FCCIA may be involved in regulation of the bone marrow microenvironment an that it varies in normal individuals and in patients with different diseases.

Evidence is presented below that normal human sera contain a potent non-dialyzable factor inducing abundant giant fat cells in human bone marrow culture, normal as well as CML. Media with 20% heated (56 degrees C) human serum induce during 7-14 days almost complete monolayer of fat cells on the bottom of the plastic flasks or dishes. Fetal bovine sera do not exhibit this effect and shift cultures to the proliferation of fibroblasts. We are studying the functions of fat cells in hemopoiesis as well as the biochemical nature of fat cell-inducing factor in human sera.

The large unitary conductance Ca2+-activated K+ channel is a widely distributed channel in cellular membranes of diverse tissues. This type of channel may serve as a link between membrane excitability and cell metabolism. In this review we discuss some aspects of the gating mechanism, calcium activation and function and modulation of BK channels.

The effects of a single oral dose of 2.5 mg bromocriptine on serum level of TSH and prolactin were studied in a group of normal male subjects. Bromocriptine effectively inhibited basal TSH and prolactin concentration as well as the prolactin and TSH response to TRH given 4 hours later. The prior administration of the extracerebral dopamine antagonist domperidone reversed the endocrine effects of bromocriptine. The results suggest that dopamine receptors located at the pituitary may regulate TSH (and prolactin) release in man.

1. Muscle fibres from Megabalanus psittacus (Darwin) were used to measure the exchange of Na+ and Ca2+ between intracellular and extracellular compartments. 2. The size of the extracellular space was evaluated directly from electron micrographs at 6.1 +/- 0.5% (percentage of the fibre volume). The more conventional estimates using Na+ and 134Cs+ as space markers gave higher values, namely, 8.9 +/- 0.7 and 9.5 +/- 1.5%. 3. An average value of 9.2% was used to correct the total Na+ and K+ in the muscle fibres and to estimate the intracellular concentrations of Na+ and K+ as 39 +/- 4 and 202 +/- 11 mM respectively. 4. Na+ (and similar Ca2+) washout curves could be described using a three compartments diffusion model. The data analysed in terms of this model enabled us to estimate membrane permeabilities as PNa+ = 2.7 x 10(-7) and PCa2+ = 2.7 x 10(-7) cm/sec.

The sensitive dansyl procedure was used to detect putrescine and spermidine, but not spermine and cadaverine, in pleomorphic Trypanosoma brucei. The polyamines were synthesized in vitro from [3H]ornithine, [14C]arginine and [14C]methionine. Proline, agmatine, and citrulline, but not glutamine, glutamic or pyroglutamic acids, stimulated spermidine formation from [4C]methionine. Putrescine and sperimidine synthesis occurred rapidly from ornithine: putrescine synthesis peaked in 0.5 h, spermidine in 1 h. Trypanosoma brucei assimilated exogenous 14C-labeled putrescine, spermidine, and spermine; spermidine and spermine were taken up 5 times as rapidly as putrescine. Polyamine syntheses may therefore be a practical target for novel trypanocies.