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Biomedical subjects

G Huszar

Publications and source records attributed to G Huszar.

At least 37 records · Page 2Linked to original sources
PubMed1990

Hyaluronic acid (Sperm Select) improves retention of sperm motility and velocity in normospermic and oligospermic specimens.

The effects of Sperm Select (Pharmacia AB, Uppsala, Sweden), a hyaluronic acid medium, on the motility and membrane integrity properties of sperm were studied. In 15 normospermic specimens after overnight incubation, the motility parameters in the control versus the Sperm Select group were as follows (mean +/- SEM): motility, 18.8% +/- 2.8% versus 27.4% +/- 2.9%; velocity, 21.5 +/- 2.4 versus 27.2 +/- 2.2 microns/s; linearity, 3.8 +/- 0.3 versus 4.4 +/- 0.2; lateral head displacement, 1.5 +/- 0.2 versus 1.9 +/- 0.1 microns; and tail beat/cross frequency, 8.8 +/- 1.3 versus 10.8 +/- 1.4 Hz. The density of motile sperm was 10.8 +/- 2.3 versus 18.5 +/- 2.5 X 10(6) sperm/mL. Finally, the velocity coefficient, the multiple of the sperm motility and linear velocity, was 4.6 +/- 1.1 versus 8.1 +/- 1.4. However, we found no Sperm Select related differences when testing sperm membrane integrity with hypoosmotic swelling and supravital staining. Thus, Sperm Select improves the retention of sperm motility (most prominently velocity) apparently due to a direct action of hyaluronic acid on sperm metabolism or contractility rather than to preservation of sperm membrane integrity. In 20 oligospermic specimens, Sperm Select caused similar improvements in sperm motility, and the duration of motility could be predicted from the degree of enhancement in sperm velocity after short-term Sperm Select exposure. A modified Sperm Select protocol is described that further increases motile sperm yield without a centrifugation step.

Bisbenzimidazole↗
PubMed1988

Correlation between sperm creatine phosphokinase activity and sperm concentrations in normospermic and oligospermic men.

Toward the development of biochemical probes for the assessment of sperm function we have measured the activities of sperm creatine-N-phosphotransferase (CPK). There was a highly significant inverse correlation (P less than 0.001 in all comparisons) between sperm CPK activities and sperm concentrations in specimens of normospermic and oligospermic men with greater than 30 million sperm/ml (0.106 +/- 0.01 SEM, N = 90, expressed as CPK U/100 million sperm), 20-30 million sperm/ml (0.333 +/- 0.07 SEM, N = 30) and 10-20 million sperm/ml (0.583 +/- 0.12 SEM, N = 30) when compared with the CPK values of the less than 10 million/ml specimens (2.242 +/- 0.46 SEM, N = 30). Furthermore, the distribution of CPK activities within these four groups showed that 96%, 67%, 43%, and 4% of the samples, respectively, were in the less than 0.250 CPK U/100 million sperm normal range (mean + 2 SD of the greater than 30 million sperm/ml group). However, there was no relationship between sperm CPK activities and the values of sperm motility (P greater than 0.15) or morphology (P = 0.38) in the samples. The migrated sperm fractions (significantly improved in motility and velocity parameters) showed CPK activities lower than the initial semen specimens (P less than 0.01, N = 150). In fact, in some oligospermic men the CPK activities of the migrated sperm fractions were within the range of normospermic samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Creatine Kinase↗
PubMed1988

Sperm creatine phosphokinase activity as a measure of sperm quality in normospermic, variablespermic, and oligospermic men.

We have found a significant inverse correlation between sperm concentrations and sperm creatine N-phosphotransferase (CPK) activities in oligospermic and normospermic human specimens. In the present work, we carried out serial CPK determinations to assess whether there is a relationship between fluctuating sperm concentrations and sperm quality in consistently oligospermic and variablespermic (sperm concentrations are occasionally in the greater than 20 million/ml range) husbands of 65 couples (23 normospermic men/51 samples, 25 consistently oligospermic men/80 samples, and 17 variablespermic men/68 samples). The sperm CPK activities were significantly lower in the normospermic vs. the oligospermic or variablespermic groups (p less than 0.001), but there were no differences between the latter two (p greater than 0.25). The mean CPK values of migrated sperm fractions in both the oligospermic and variablespermic populations were improved (at least 20% decline in CPK values) compared to those of the initial specimens (1.27 +/- 0.38 vs. 0.68 +/- 0.37 and 0.77 +/- 0.32 vs. 0.46 +/- 0.24 SEM U/100 million sperm, respectively, p less than 0.001 in both pairs) and the incidence of the "failed-to-improve" samples was also similar in the two groups (44/36 vs. 45/23, p greater than 0.2). The lack of differences in the mean CPK activities, in the distribution of CPK values under and over 0.250 U/100 million sperm level, and in the ratio of migrated samples with improved or with failed-to-improve CPK activities suggests that sperm quality is not different between men who are consistently oligospermic and those who occasionally produce normospermic specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Creatine Kinase↗
PubMed1986

Pharmacologic levels of nitrendipine do not affect actin-myosin interaction in the human uterus and placenta.

Because of the potential of dihydropyridine calcium channel blockers in the management of premature labor, we have studied the direct effects of nitrendipine on actomyosin in the pregnant and nonpregnant uterus and in the term human placenta. Actomyosin adenosinetriphosphatase in the three tissues and another model of actin-myosin interaction, superprecipitation of placental actomyosin, were inhibited by nitrendipine. The inhibition was not diminished by high concentrations of calcium. To identify the mechanism, placental myosin was phosphorylated in the absence and presence of 0.8 X 10(-4) mol/L of nitrendipine. The myosin phosphorylated in the presence of nitrendipine had lower actin-activated adenosinetriphosphatase, which is consistent with the inhibition of myosin light chain phosphorylation. However, nitrendipine did not affect the adenosinetriphosphatase activity of myosin nor did further reduce the adenosinetriphosphatase of the already phosphorylated placental actomyosin. Thus nitrendipine inhibition is directed to the phosphorylation reaction but not to the adenosinetriphosphatase site of myosin. Myometrial relaxation in vivo or in vitro occurs at the pharmacologic nitrendipine levels of 10(-9) to 10(-8) mol/L, which is at least 10,000 times lower than that of the concentration of 50% inhibition of myosin light chain phosphorylation (0.0026 +/- 0.00015 mol/L of nitrendipine, mean +/- SEM) demonstrated in the present work. Because of this difference, the direct intracellular actions of dihydropyridine calcium channel blockers are not expected to cause adverse effects in the uteroplacental system when these drugs are used in the prevention or treatment of premature labor.

Actins↗
PubMed1986

Enhancement of human sperm motility and velocity in vitro: effects of calcium and creatine phosphate.

Because of their roles in motility regulation and energy transport, calcium and creatine phosphate were examined for their effects on sperm motility and velocity in specimens of normal donors. Semen or migrated sperm fractions were incubated with of 1 mmol of calcium, 5 mmol magnesium, and 10 mmol of creatine phosphate (n = 28) or in the presence of 4 mumol of Verapamil, calcium, and creatine phosphate (n = 10). The samples were subjected to multiple exposure photography (four picture frames of two different drops) at 0, 1, 4, or 5 and at 10 hours and sperm motility and velocity were analyzed. In both calcium and calcium-creatine phosphate conditions, sperm motility and velocity were significantly increased, compared with control values (P = between less than 0.001 and 0.05). Sperm motility declined following Verapamil exposure, but the motility values remained at the level of the control in the presence of additional calcium or creatine phosphate. The effects of calcium and creatine phosphate take place rapidly; within 1 minute all improvements in sperm velocity and motility are fully achieved. There is no loading effect of calcium, and when the sperm is transferred into media without the additional calcium, the velocity decreased to that of the initial control value. Magnesium alone had no effect on motility or velocity. These experiments indicate that calcium or creatine phosphate can support sperm motility and velocity at a significantly increased level. Thus the addition of calcium or creatine phosphate to the insemination media may enhance the fertilizing capacity of sperm during in vitro fertilization or gamete intrafallopian transfer procedures.

Calcium↗
PubMed1985

Myosin heavy chain in avian muscular dystrophy corresponds to the neonatal isozyme.

We have previously demonstrated, based on comparison of homologous amino acid sequences and of two-dimensional CNBr peptide gel patterns, that the myosin heavy chain in pectoralis muscles of Storrs, Connecticut dystrophic chickens is different from that of their normal controls (Huszar, G., Vigue, L., De-Lucia, J. Elzinga, M., and Haines, J. (1985) J. Biol. Chem. 260, 7429-7434). Others have shown, however, that genomic banks and mRNA complements of the control and dystrophic birds are not different. In the present studies, we have examined the hypothesis that the "dystrophic" myosin heavy chain is not a novel gene product, but is a developmental isozyme which is expressed in pectoralis muscles of adult chickens due to the dystrophic process. Two-dimensional maps of myosin heavy chain CNBr peptides were prepared from breast muscles of 17-day in ovo (embryonic), 25-day posthatch (neonatal), and adult birds of the Storrs dystrophic and of two control strains. Also, myosin and actomyosin ATPase enzymatic activities of the various preparations were determined in the pH range of 5.5 to 9.0. Analysis of the peptide maps demonstrates that the embyronic, neonatal, and control adult myosin heavy chain isozymes are distinctly different gene products with only minute variations between the respective developmental isozymes in dystrophic and control muscles. However, the pectoralis myosin heavy chain of adult dystrophic birds, which is a homogeneous isozyme population by amino acid sequences and gel patterns, corresponds to that of the neonatal-type myosin heavy chain. The ATPase properties of the embryonic, neonatal, or adult pectoralis myosins and actomyosins were not different, whether the level of specific activity or the pattern of pH activation is considered. Since the mobility of neonatal chicks (primarily neonatal-type isozymes) is not restricted, the differences in myosin heavy chain structures are part of the syndrome, but not the cause of avian muscular dystrophy.

Adenosine Triphosphatases↗
PubMed1985

Structure of myosin heavy chain in avian muscular dystrophy.

We have studied the structure of myosin heavy chain (MHC) in the pectoralis muscle of genetically dystrophic (Connecticut Strain) and White Leghorn chicks. MHC was alkylated with N-ethylmaleimide, purified by Sepharose-4B chromatography, and cleaved with cyanogen bromide. The MHC CNBr peptides were analyzed by one-dimensional and two-dimensional isoelectric focusing/sodium dodecyl sulfate gradient gels and by amino acid sequencing. Specific changes were detected in the gel patterns which could be correlated with the loss of muscle function as measured by the exhaustion score (the ability of chicks to rise from a reclining position) in three experimental groups (exhaustion scores: less than 3, 10-20, greater than 30). We have also examined the amino acid sequence of a 3-methyl-histidine-containing peptide which originates from the 20-kDa fragment of pectoralis muscle MHC in dystrophic chicks: Val-Leu-Asn-Ala-Ser-Ala-Ile-Pro-Glu-Gly-*Gln-Phe-*Ile-Asp-Ser-Lys-Lys- Ala-Ser-Leu-Gln-Lys-Leu-Gly-Ser-Ile-Asp-Val-(Asp, 3-methylhistidine, Gln). Comparison of the homologous MHC sequences shows two positions at which MHC from dystrophic chicks differs from that of the White Leghorn chicks *(Glu----Gln and Met----Ile). Thus, both the peptide map and sequence analyses demonstrate that in avian muscular dystrophy an abnormal pectoralis MHC is synthesized. It is not yet clear whether the "dystrophic" MHC is a variant MHC or if it arises from the abnormal expression of an earlier developmental form (embryonic or neonatal) of pectoralis muscle MHC.

Amino Acid Sequence↗
PubMed1984

Improved techniques for collecting motile spermatozoa from human semen. I. A self-migratory method.

A simple apparatus to collect moving sperm by non-traumatic means which can be used for artificial insemination is described. The technique is based on enhancing the process of migration from the seminal fluid into a top-layered artificial medium in an ordinary test tube. This has been achieved by controlling 3 main variables: 1) The dilution of migrated sperm was minimize by using only 0.5 ml of the medium layered onto 1 ml semen; 2) increasing the surface area between these media by turning the test tube from a vertical to almost a horizontal position; 3) stimulating sperm activity by incubation at 37 degrees C under air: 5% CO2 for 30 min. When restored to a vertical position approximately 0.3 ml medium, sufficient for most AIH or IVF procedures, was gently aspirated. The effects of these variables on the rate of sperm migration was tested one at a time, and increments that ranged from 20% to as much as 10-fold were detected. When these 3 variables were optimized and 58 semen specimens analyzed, it was found that motility increased from 42 to 87%, velocity from 24.5 to 27.3 micron per sec, whilst abnormal forms dropped from 37 to 15%. The final concentration of motile sperm was 23 X 10(6)/ml compared to an original mean concentration of 34 X 10(6)/ml, indicating a relative recovery of 68%. Oligoasthenospermic specimens revealed similar changes in sperm motility, velocity, morphology and recovery. However, due to the low initial content of moving sperm (4.8 X 10(6)/ml), their final concentration was also low (2.7 X 10(6)/ml). Such specimens required additional preliminary preparation to increase the sperm concentration prior to the migratory procedure.

Cell Separation↗
PubMed1984

Improved techniques for separating motile spermatozoa from human semen. II. An atraumatic centrifugation method.

A simple and atraumatic method for concentrating washed, motile spermatozoa from normal and subnormal semen specimens is described. It incorporates a modified technique of centrifugation in which sperm are spun onto a soft, fluid cushion, thereby minimizing mechanical damage. Following initial semen dilution to 5-10 ml in an artificial medium, the mixture is transferred to a test tube and layered onto 1 ml of oily contrast medium (Lipiodol). After centrifugation at 300 g for 10 min all but 0.5 ml of the supernatant is discarded, and the unshaken test tube is incubated at 37 degrees C for 15-20 min, during which time the motile sperm migrate into the upper 0.5 ml. After this incubation, 0.3 ml of the upper layer is removed which is sufficient for most IVF and AIH purposes. It contains concentrated, washed, motile spermatozoa that are free of debris and most abnormal forms. No change in pH or osmolarity and no diffusion of any iodine from the oil base into the top layer were detected.

Cell Separation↗
PubMed1984

Influence of exercise on urea, creatinine, and 3-methylhistidine excretion in normal human subjects.

To evaluate the effects of exercise on net protein catabolism, the losses of urea in sweat and urine and urinary creatinine and 3-methylhistidine (3MH) excretion were determined in eight healthy subjects during cycle ergometer exercise performed at approximately 45% of VO2max for 90 min. The subjects ingested a meat-free diet for 5 days starting 3 days before and continuing for 1 day after the day of exercise. During exercise, total urea excretion (urine + sweat losses) increased 100% above pre- and postexercise values. Thirty percent of the total urea excretion during exercise was in the form of sweat losses. Total protein breakdown (as reflected by urea excretion), however, could account for less than 5% (21 +/- 4 kcal) of total calorie expenditure during the exercise (567 +/- 83 kcal). Urinary creatinine excretion increased by 50% during exercise. Urinary excretion of 3MH also tended to rise, but the ratio of urinary 3MH to creatinine showed no change in response to exercise. We conclude that 1) light to moderate exercise results in an increase in net protein catabolism and an increase in creatinine excretion; 2) sweat losses are an important route for urea excretion during exercise; 3) there is no evidence of a disproportionate increase in breakdown of myofibrillar contractile proteins; and 4) in spite of the increase in the rate of protein catabolism, protein is only a minor source of energy during light to moderate exercise.

Adolescent↗
PubMed1984

Nitrendipine prolongs rat parturition: no changes occur in progesterone withdrawal.

The mechanism of tocolytic action of the calcium channel-blocking agent nitrendipine [3-ethyl-5-methyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl) 3,5-pyridinedicarboxylate; BAYER E 5009] had been examined. Pregnant rats (duration of pregnancy, 22 days) were treated with nitrendipine (12.5 mg/kg, sc) on days 18-21 of gestation (group I) or on days 20-21 of gestation (group II) and with vehicle only (control group). Serum levels of progesterone from the three experimental groups were determined on days 20 and 22, and the course of labor was monitored on days 22-23 in the individually caged dams. The duration of labor, delivery times, and other labor parameters were significantly delayed in the treated groups vs. the control group, while there was no difference in serum progesterone levels among the three experimental groups on day 20 or 22 of gestation 136.0 +/- 5.6 (mean +/- SEM; (n = 6) and 43.8 +/- 7.2 (n = 17) ng progesterone/ml serum, respectively. We can conclude that progesterone withdrawal, the primary event in the initiation of rat labor, is not altered by nitrendipine treatment. The delay of labor is apparently related to a decrease in the contractile state of myometrium due to the inhibition of calcium influx by nitrendipine.

Animals↗
PubMed1983

Urinary 3-methylhistidine excretion in man: the role of protein-bound and soluble 3-methylhistidine.

The influence of dietary meat and meat stock intake on urinary excretion of 3-methylhistidine (3MH) was examined in human adults. In the absence of 3MH ingestion for 48 h, the study subjects adjusted to an intrinsic urinary 3MH: creatinine value. If the meat and meat stock-free diet was maintained on subsequent days, only minute diurnal variations occurred, and the values of random urine samples during the day were representative of the 24 h 3MH: creatinine value. The mean 3MH: creatinine value (SD) for a group of adults (n 7) was 0.105 +/- 0.023 (mumol of 3MH/mg creatinine), which is approximately 35% lower than the corresponding value in healthy growing infants (0.148 +/- 0.039) (Seashore et al. 1981). Ingestion of meat soup and meat causes different patterns of urinary excretion of 3MH which are consistent with the finding that meat extracts, such as soup and stock, contain considerable amounts of 3MH. The 3MH contents of beef, chicken and turkey were 3.8 +/- 0.15, 3.0 +/- 0.09 and 2.3 +/- 0.29 mumol/g dry wt meat respectively. All three meats contained a water-soluble 3MH-fraction (% total 3MH: beef 8, chicken 21, turkey 23). Amino acid analysis of the soluble fraction with or without hydrochloric acid hydrolysis demonstrated free 3MH in chicken and turkey (5.2 and 2.8% of the total respectively) but not in beef. Patients undergoing urinary 3MH measurements should maintain a diet that is free not only of solid meats, but also of meat stock. The ingestion of commercial food products (e.g. frozen or canned meals, sauces, pizza, etc.) may impair the validity of such measurements because of their meat-stock content. A dietary regimen is presented which is based on a shorter 12 h urine collection. The shorter collection time is satisfactory in the light of the steady rate of 3MH-excretion after 2 d of a diet free of meat and meat stock.

Adult↗
PubMed1982

Biochemistry and pharmacology of the myometrium and labor: regulation at the cellular and molecular levels.

This review presents the essentials of cell biology, biochemistry, and pharmacology of the myometrium and labor, especially as they relate to premature labor. The aim is to explore the neuroendocrine and pharmacologic regulation of myometrial muscle cells in the context of cell membrane function and contractile processes. In the first section, smooth muscle protein structure and interactions are described, the central roles of myosin light-chain kinase, calcium, and cyclic adenosine monophosphate (cAMP) are reviewed. Subsequently, events relating to hormone/drug receptor function and implications for pharmacologic applications are discussed. Finally, the processes of information transfer via hormones and drugs are incorporated into a model which explains how the hormones and drugs used in clinical practice may mediate myometrial contractility. The reader is introduced to current concepts of the cellular, molecular, and pharmacologic aspects of labor in order to facilitate the understanding of medical augmentation of labor and tocolytic therapy.

Actins↗
PubMed1982

Urinary 3-methylhistidine excretion in juvenile-onset diabetics: evidence of increased protein catabolism in the absence of ketoacidosis.

Urinary 3-methylhistidine excretion (an indicator of protein catabolism) was measured in ten diabetic patients and in age and weight matched control subjects. The diabetic group, while receiving their usual insulin dose, excreted 42% more 3-methylhistidine than the control group (2.7 versus 1.9 mumole/kg body weight/24 hr). When the insulin dose of the diabetic subject was reduced by 15% or 25%, the concentrations of blood and urinary glucose were significantly increased by the rate of urinary 3-methylhistidine excretion was not increased further. These findings demonstrate augmented protein catabolism in diabetics even in the absence of ketoacidosis. It appears that blood and urine glucose levels are more sensitive to changes in insulin availability than protein catabolism.

Adult↗
PubMed1982

Effects of acute cold exposure on muscle amino acid and protein in rats.

To test the effects of acute cold on muscle amino acid and protein 1) rats were exposed to 4 degrees C for 24 h, functionally hepatectomized (eviscerated) and accumulation in the blood used to indicate changes in amino acid release from the tissues; 2) other rats were left intact, and urinary excretion of 3-methylhistidine (proportional to muscle protein breakdown) determined during cold exposure. In the eviscerated group, cold enhanced loss of total amino acids from the tissues (as alpha-amino nitrogen), but the loss (213 +/- 14.8% of basal in 2 h) was not due to excess alanine (180 +/- 8.5%). By comparison, in fasted rats total amino acid was 182 +/- 12.3, alanine 309 +/- 17.2%. Also, the cold-induced loss resembled the effects of streptozotocin diabetes and depended on a depression by cold of serum insulin (to 35.7 +/- 2.3 muU/ml). Therefore it was prevented when insulin was restored by infusion (40 mU . 100 g-1 . h-1) or by adrenodemedullation before cold exposure. Epinephrine (10 micrograms/100 g sc) depressed insulin in the latter and permitted amino acid release to recur. In intact rats, 3-methylhistidine excretion was unaffected by cold. The results suggest that although cold fails to stimulate alanine synthesis or protein breakdown, it inhibits insulin release sympathetically, thereby diminishing the amount of amino acid incorporated into muscle protein.

Adrenal Medulla↗