JC-1: alternative excitation wavelengths facilitate mitochondrial membrane potential cytometry.

Mitochondrial membrane potential provides a valuable indicator of cells' health and functional status. Cytometry- and microscopy-based analyses, in combination with fluorescent probes, are widely used to study mitochondrial behavior related to cellular pathways, most notably - apoptosis. The cyanine dye JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimi- dazolylcarbocyanine iodide) facilitates discrimination of energized and deenergized mitochondria because the normally green fluorescent dye forms red fluorescent aggregates when concentrated in energized mitochondria in response to their higher membrane potential. JC-1 fluorescence is usually excited by the 488 nm laser wavelength common in flow cytometers. In this study, we show that in practice this approach is not optimal for monitoring mitochondrial behavior. Investigation of fluorescence of JC-1 in solution and in cells using spectrofluorimetry, microscopy and flow cytometry reveals that excitation at 405 nm wavelength, now available on standard instruments, produces signals from aggregate fluorescence with considerably less spillover from dye monomer fluorescence than can be obtained using 488 nm excitation. The improved data are more accurate and eliminate the necessity for fluorescence compensation, making the use of the alternative excitation wavelengths beneficial for mitochondria-related biological and biomedial research.

Plasma homocysteine levels in obstructive sleep apnea: association with cardiovascular morbidity.

OBJECTIVES: Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity and mortality. Plasma levels of homocysteine are also associated with cardiovascular morbidity and mortality. We therefore investigated homocysteine and conventional cardiovascular risk factors in OSA patients with and without cardiovascular morbidity in comparison with normal control subjects and ischemic heart disease (IHD) patients without OSA. SETTING: Technion Sleep Medicine Center, Haifa, Israel. METHODS AND PARTICIPANTS: Levels of homocysteine, cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, creatinine, vitamins B(12) and B(6), and folic acid were determined in 345 participants after overnight fasting. These included OSA patients with IHD (n = 49), with hypertension (n = 61), or without any cardiovascular disease (n = 127). Two control groups were employed: IHD patients without or with low likelihood for sleep apnea (n = 35), and healthy control subjects (n = 73). RESULTS: After adjustment for age, body mass index, creatinine, and existence of diabetes mellitus, OSA patients with IHD had significantly higher homocysteine levels (14.6 +/- 6.77 micromol/L) than all other groups including the IHD-only patients. Hypertensive OSA patients had comparable homocysteine levels to IHD patients (11.80 +/- 5.28 micromol/L and 11.92 +/- 5.7 micromol/L, respectively), while patients with OSA only had comparable levels to normal control subjects (9.85 +/- 2.99 micromol/L and 9.78 +/- 3.49 micromol/L, respectively). No differences in conventional cardiovascular risk factors or in vitamin levels were found between groups. CONCLUSIONS: Patients with the combination of IHD and OSA have elevated homocysteine levels. We hypothesize that these results may be explained by endothelial dysfunction combined with excess free-radical formation in OSA patients.

Scattering by particles with radially variable refractive indices.

The problem of scattering by a spherical particle whose refractive index arbitrarily depends on the distance from its center has been solved. A computational scheme for determining the scattering coefficients for the refractive-index profiles given by some piecewise smooth function is constructed, and the models to use it are presented. The simple algorithm for evaluating the scattered and internal field vectors is elaborated. The exact expression for the scattering cross section in terms of the generated Debye partial potentials that are dependent on the given refractive index has been obtained.

Long-term effectiveness of depot gonadotropin-releasing hormone analogue in the treatment of children with central precocious puberty.

OBJECTIVE: To assess the efficacy and safety of a long-acting gonadotropin-releasing hormone analogue (GnRHa), leuprolide acetate for depot suspension (Lupron Depot), in the treatment of central precocious puberty in children, and to determine the reversibility of GnRHa therapy after it has been discontinued. RESEARCH DESIGN: Children with documented central precocious puberty were treated with Lupron Depot for 1.6 to 3.5 years. Their course of pubertal development, growth rate, skeletal maturation, and response to gonadorelin hydrochloride testing were compared before and during treatment. For those girls who finished treatment, an assessment of the reversibility of the GnRHa was performed by documenting a return to pubertal responses to gonadorelin testing, and by documenting menarche at an appropriately mature bone age. SETTING: Community teaching hospital. PATIENTS: Ten girls with central precocious puberty defined as pubertal maturation statistically advanced for age combined with a pubertal gonadotropin response to gonadorelin testing. Children who had been treated for less than 1.5 years were excluded, as were those with congenital adrenal hyperplasia. Patients who finished treatment have been followed up for up to 5 years, and will continue in follow-up throughout their reproductive life. SELECTION SAMPLE: A consecutive group of children with documented central precocious puberty was studied. INTERVENTIONS: Lupron Depot was administered as a single monthly subcutaneous injection to each patient. Treatment was usually discontinued by 10 to 11 years of age, at which time pubertal progression was allowed to resume. MEASUREMENT AND RESULTS: Mean peak serum concentrations of follicle-stimulating and luteinizing hormone responses to gonadorelin testing decreased significantly after the initial dose (from 21.8 +/- 4.5 [+/- SEM] to 2.4 +/- 0.2 IU/L for follicle-stimulating hormone and from 50.1 +/- 11.2 to 5.0 +/- 0.8 IU/L for luteinizing hormone) and remained suppressed for the duration of treatment. The progression of puberty slowed or reversed in all patients. Mean growth rate for chronologic age was significantly increased initially by 3.9 SDs and decreased to 0.9 SDs during treatment. The mean rates of skeletal maturation divided by the change in chronologic and height age changes over time were advanced (1.4 +/- 0.1 and 1.1 +/- 0.15, respectively) at the onset of therapy and decreased significantly to 0.7 +/- 0.1 and 0.8 +/- 0.1, respectively, on treatment. There was an increase in mean predicted height of 3.4 cm for all patients, and this was statistically significant. Thus, treatment with Lupron Depot at least maintained the predicted height at the onset of therapy. Girls who completed their course of treatment had pubertal gonadotropin responses to gonadorelin testing within 2 to 6 months, and menarche within the first year if skeletal maturation reached 13.0 to 13.5 years. No significant side effects of therapy were noted. CONCLUSIONS: Treatment of central precocious puberty in children using Lupron Depot is safe and efficacious. Its effects are readily reversible after treatment is discontinued, and menarche occurs at a normal bone age. Measurement of serum luteinizing hormone concentrations using an assay that is specific for the beta-subunit is necessary to monitor chemical suppression of luteinizing hormone during treatment. Longer-term studies, including reproductive history, will be needed before the potential effects of treatment on fertility can be assessed.

The fetus in maternal hyperthyroidism.

A recent article in the New England Journal of Medicine reported the successful diagnosis and treatment of fetal goitrous hypothyroidism in a mother with Graves' disease. The fetus is being recognized as an important patient in its own right in terms of thyroid disease. The fetal thyroid system develops independently of the normal maternal thyroid axis. Presence of feedback suppression of TSH by T4 has been demonstrated in a 35-week fetus. Information learned from congenital hypothyroidism suggests that lack of fetal thyroid hormones may have a negative impact on the developing fetal brain with lack of normal myelination. It is uncertain at what gestational age the fetus and the developing central nervous system become adversely affected by thyroid hormone deficiency. Since congenital hypothyroidism is sporadic and since there is no current method for easily screening all pregnancies for hypothyroidism, the thrust in fetal diagnosis and therapy has been in those pregnancies suspected of having a hypothyroid fetus when a fetal goiter is detected by ultrasonography or in a hyperthyroid mother who may be on antithyroid therapy. Intraamniotic injections of L-thyroxine have proven successful for fetal therapy. Amniotic fluid TSH may prove useful in the diagnosis and treatment of a hypothyroid fetus. Previous studies have suggested that the period of thyroxine dependency of the fetal central nervous system is limited predominantly to the last 4-8 weeks of gestation. Fetal hyperthyroidism due to transplacental transmission of thyroid-stimulating immunoglobulins may occur in a mother with a history of hyperthyroidism due to Graves' disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Extinction and scattering by soft spheres.

On the basis of an approximate relation, the Mie series are replaced by new ones, which can be summed exactly with the aid of various modified and generalized forms of the addition theorem for cylindrical functions. The sums obtained simultaneously simplify the initial expressions for the scattering characteristics and preserve their analytical nature. The conventional approximations for the amplitude functions and the efficiency factors rigorously follow from the new approaches if the optical parameters are properly restricted. The acceptable domains of these approaches contain the long wavelength region and are extensive enough to study the various (including inverse) scattering problems for the real disperse systems, in which the particles are suspended in a medium with similar optical properties.

[Biotechnological aspects in "loco" larvae]. / Aspectos biotecnológicos en larvas de "loco".

The biology of planktotrophic larvae of Concholepas concholepas is the main bottleneck towards developing biotechnologies to rear this muricid. Data concerning planktonic larvae development, diets and environmental signals triggering larval settlement and recruitment is scarce. We have begun the study of the molecular and cell biology of embryos, larvae and recruits having as a final goal, the development of appropriate biotechnologies to rear this gastropod. First, an inverse ratio between BuChE and AChE enzyme activities was established. This ratio may be a precise developmental marker for this species. Second, for the first time a phosphoinositide related regulatory pathway is reported in a muricid, opening a new approach to the biotechnological management of larvae. Third, the relation between sulfate in sea water and larval motility was studied. Concentrations below 125 microM sulfate decreases larval motility. The sulfate is incorporated in proteoglycans which participate in different developmental phenomena. Lastly, a genomic Concholepas concholepas DNA sequence, similar to that of a human growth hormone probe was detected. This is very interesting since growth factors are key molecules during development, growth and are involved in food conversion rates in fish and also, in a variety of marine invertebrates.

Intrauterine diagnosis and treatment of fetal goitrous hypothyroidism.

Newborn screening programs for the detection of congenital hypothyroidism have dramatically shortened the time before treatment is begun. However, concern still exists about central nervous system sequelae which may persist due to a period of untreated intrauterine hypothyroidism. Presence of polyhydramnios led to the ultrasound diagnosis of a fetal goiter. Hypothyroidism was confirmed at 34 weeks gestation by percutaneous fetal blood sampling, which revealed an elevated TSH (186 mU/L) and a low T4 (19.3 nmol/L). Intraamniotic fluid injections of 500 micrograms levothyroxine sodium (T4) every 10-14 days increased fetal serum T4 (59.2 nmol/L), decreased fetal serum TSH (14 mU/L), decreased amniotic fluid TSH, and decreased the size of the fetal goiter. The infant was born at term without perinatal complications. Thyroid function studies on cord blood were normal (T4, 109.4 nmol/L; TSH, 1.3 mU/L), and the infant was discharged on oral T4. Follow-up examination at age 6 weeks revealed that the infant was developmentally normal and clinically and chemically euthyroid. Intrauterine T4 therapy can suppress fetal TSH and treat fetal hypothyroidism despite hypothyroid levels of serum T3. Highly sensitive TSH assays may allow the use of amniotic fluid TSH as a marker for fetal hypothyroidism.

Differential association and distribution of acetyl- and butyrylcholinesterases within rat liver subcellular organelles.

Rat liver cholinesterases were found to share properties and characteristics with those expressed in cholinergic tissues. The distribution and presence of different molecular forms of cholinesterases in different subcellular organelles of rat liver were studied. The rough and smooth endoplasmic reticulum and Golgi apparatus were enriched in the G4 molecular form of acetylcholinesterase (AChE) (relative to the G2 molecular form), while the inverse was found in the plasma membrane. The interaction of these molecular forms of AChE with the Golgi membrane was studied in detail. Approximately one-half of the G4 form was free within the lumen while the remainder was an intrinsic membrane protein; all the G2 molecular form was anchored to the membrane via phosphatidylinositol. Only the G1 and G2 molecular forms of butyrylcholinesterase (BuChE) were found in the above subcellular organelles; both molecular forms were soluble within the lumen of Golgi vesicles. These results indicate that rat liver expresses several molecular forms of AChE which have multiple interactions with membranes and that liver is unlikely to be the source of the G4 form of BuChE present in high concentration in the plasma.

Suppression of gonadotropin secretion by a long-acting gonadotropin-releasing hormone analog (leuprolide acetate, Lupron Depot) in children with precocious puberty.

The GnRH analog leuprolide acetate has been shown to be effective in the treatment of precocious puberty when given as a daily sc injection. We studied the effectiveness of a single im dose of a new depot form of leuprolide in suppressing estradiol and gonadotropin secretion in children with precocity. Five girls with previously untreated precocity showed significant decreases in basal serum estradiol and FSH levels and in peak LH levels (after GnRH testing) 30 days after a single im dose of leuprolide acetate for depot suspension. Mean peak FSH levels also fell greatly, but the difference was not significant. No adverse effects were noted during the first 4-6 months of monthly im injections. Depot im leuprolide appears to be effective in suppressing estradiol and gonadotropin secretion, and may be a useful method of treating children with central precocious puberty.

Distribution and anchoring of molecular forms of acetylcholinesterase.

Molecular forms of acetylcholinesterase exhibit tissue-specific distribution, and each form is anchored to the cell surface via a particular post-translational modification of the catalytic subunit. Nibaldo Inestrosa and Alejandra Perelman review evidence that heparan sulphate proteoglycans are the extracellular matrix receptors for the collagen-tailed enzyme, and that a glycolipid which contains phosphatidylinositol and a 20 kDa hydrophobic peptide participate in the anchoring of the hydrophobic globular forms of acetylcholinesterase to the cell surface.

A simple assay to estimate the acetylcholinesterase molecular forms in crude extracts of rat skeletal muscle.

All the current methods available for analyzing the acetylcholinesterase (AChE) molecular forms are time consuming and require the use of expensive equipment. We have found that by using the differential inactivation of globular (G4 + G1) and asymmetric AChE forms by high Mg2+ concentration, we can set up a very easy and quick assay that allows us to determine the relative proportions of AChE molecular forms present in rat skeletal muscles. This assay will be of great help in estimating changes in the muscle AChE forms under experimental conditions that require several simultaneous determinations.

Different membrane-bound forms of acetylcholinesterase are present at the cell surface of hepatocytes.

In the present study we have determinated the acetylcholinesterase molecular forms present in rat liver hepatocytes; we have also studied the association of acetylcholinesterase with the cell surface of the hepatocytes. Subcellular fractionation indicated that rough endoplasmic reticulum and plasma-membrane-enriched fractions contains G4 and G2 acetylcholinesterase forms bound to membranes. Hepatocytes incubated with phosphatidylinositol-specific phospholipase C released about 70% of the surface acetylcholinesterase. Sedimentation analysis showed that all the solubilized acetylcholinesterase activity comes exclusively from a G2 dimer. The G4 hydrophobic form of acetylcholinesterase accounts for the additional cell-surface activity. The existence of these two forms of acetylcholinesterase on the surface of hepatocytes was further established by analyzing the phosphatidylinositol-specific phospholipase C sensitivity of the acetylcholinesterase molecular forms present in isolated rat liver plasma membranes.

Fetal goitrous hypothyroidism. A new diagnostic and therapeutic approach.

We present a first case in whom fetal hypothyroidism with goiter was both successfully diagnosed and treated in utero. An obstetrical sonogram at 33 weeks revealed a bilobed fetal neck mass, compatible with enlarged thyroid gland, associated with neck hyperextension, reduced gastric fluid, and polyhydramnios. Umbilical blood sampling after volume reduction amniocentesis confirmed fetal hypothyroidism with a euthyroid mother. Fetal T4 measured 1.3 micrograms/dl, free T4 0.3 ng/dl, and thyroid-stimulating hormone 186 microU. Intraamniotic levothyroxine, 500 micrograms, was given twice with a 14-day interval. The head flexed, gastric fluid increased, and amniotic fluid levels returned to normal. Prenatal (36 weeks) and neonatal blood sampling demonstrated return to euthyroid indices. Ultrasonic estimates of thyroid volume decreased by over 50%. Vaginal delivery at 39 weeks was uncomplicated. The newborn appeared normal and is being maintained on thyroid replacement therapy.

Efficacy of leuprolide therapy in children with central precocious puberty.

Eight girls with central precocious puberty were treated with the long-acting gonadotropin releasing hormone analogue leuprolide acetate (Lupron) for a period of six to 18 months. Suppression of gonadotropin and estradiol secretion and regression of secondary sexual characteristics and menses were observed while patients received a subcutaneous dose of 35 to 40 micrograms/kg/d. Growth velocity was slowed in all but one patient, and the rate of skeletal maturation was slowed even more, resulting in a stabilization or improvement in predicted adult height. There were no major side effects. Although the long-term effects of leuprolide therapy cannot be determined with this study, it appears to be efficacious in the treatment of central precocious puberty.

Infantile mammary duct ectasia: a cause of bloody nipple discharge.

Bloody nipple discharge in infancy has been rarely reported in the medical literature. Its cause is unknown. We report a three-year-old male infant and a five-month-old female infant with bloody nipple discharge. Because of persistent bloody discharge, a subcutaneous mastectomy was performed in the boy; the problem resolved in the girl after a period of observation. The specimen showed histologic changes identical to those seen in adult mammary duct ectasia. All the endocrinologic work-up was normal. We suspect that bloody nipple discharge in infancy is underreported. This is a benign condition with histologic changes similar to adult mammary duct ectasia and if persistent, should be properly investigated; biopsy or excision are not indicated.

The occult insulinoma operative localization by quick insulin radioimmunoassay.

Hypoglycemia secondary to organic hyperinsulinism in children can be caused by diffuse or localized pancreatic lesions. Differentiation between these two types of lesions is of utmost importance since the surgical approach will be different. Some tumors escape detection by all preoperative investigations including ultrasound, scintiscan, arteriography, and computerized tomography. We are reporting on a 12-year-old boy with organic hyperinsulinism in whom we were unable to localize a tumor preoperatively. Peroperative determination of insulin levels from a number of sites on the pancreas enabled us to localize an insulin-producing pancreatic adenoma. This technique can be done easily by catheterizing the splenic and portal vein through a branch of the splenic vein and by serial sampling at 2 cm intervals along the portal and splenic veins. Insulin levels at these sites were determined by quick double-antibody radioimmunoassay, which allows the determination of the insulin levels within 50 minutes after sampling. There was a perfect biochemic and anatomic correlation allowing us to perform a precise distal pancreatectomy. The technique can be used to localize pancreatic adenomas and to decide how much pancreas to remove in diffuse lesions avoiding "blind" pancreatectomies.

Studies of the fungistatic activity of antifungal compounds in mash and pelleted feeds.

The effect of calcium propionate (CP) and Agrosil (AG) as mold inhibitors in wetted mash and pelleted feed was studied using both commercial cattle and poultry rations. Number of fungal colonies isolated after pelleting was markedly reduced; however, wetting the pellets accelerated the build-up of inoculum and resulted in spoilage. The addition of CP (.3%) to the cattle ration before pelleting prevented mold proliferation during one month of storage while the number of fungal colonies counted in pellets treated with AG (.15%) markedly increased over that period. However, AG had a longer fungistatic effect than CP in preserving the mash diet. Both materials, applied at .2%, were ineffective in preserving wet pelleted poultry feed. After 17 days of storage, feed treated with either of the agents was visibly moldy. In all cases, an increase in mold population was concomitant with elevated carbon dioxide concentrations, which indicated the sensitivity of this parameter for measuring fungal activity. Fat content of the diets remained unchanged during the storage period in spite of increased fungal activity.

Neonatal adaptation: sympatho-adrenal response to umbilical cord cutting.

The present studies were designed to assess the individual effects of delivery and umbilical cord cutting on the stimulation of the sympatho-adrenal system during parturition. Pregnant ewes with time-dated singleton pregnancies were used in an acutely exteriorized fetal lamb model with an intact umbilical circulation. We observed a minimal, transient elevation in plasma catecholamines (CAT) coincident with the operative procedures and delivery. Subsequent cord clamping was observed to evoke a rapid and marked increase of both norepinephrine and epinephrine (E), maximal at 5 min and persisting over the 4-hr study period. Animals could be grouped on the basis of the observed CAT responses, severity of postpartum acidosis, the extent of free fatty acid (FFA) mobilization and degree of postpartum hypothermia. A blunted FFA response and slower correction of hypothermia were observed in the more acidotic animals despite higher CAT concentrations. One group of four animals had high peak CAT concentrations, 32,000 pg/ml norepinephrine and 35,000 pg/ml E, a deep nadir in pH of 6.88 +/- 0.09, a 2-hr delay in maximal FFA mobilization and slower correction of hypothermia. The other group of four animals had peak norepinephrine of 2800 pg/ml and E of 1100 pg/ml, a nadir in pH of 7.09 +/- 0.08, maximal plasma FFA concentration by 1 hr after cord cutting and a higher nadir in body temperature 35.7 versus 32.5 degrees C. The results demonstrate that umbilical cord cutting itself is a potent stimulus for fetal CAT release and FFA mobilization. Acidosis is capable of markedly augmenting E release in the mature fetus and obtunding chemical thermogenesis.