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At least 451 records · Page 25Linked to original sources
PubMed1986

Detection of lactate dehydrogenase B4 in human hemolysate of patients deficient in lactate dehydrogenase B subunit activity using enzyme immunoassay.

We developed a sensitive enzyme immunoassay system specific for human lactate dehydrogenase (LDH)-B4 with antiacetylated LDH-B4 Fab'-horseradish peroxidase conjugate. The enzyme immunoassay system was not interfered with by up to 0.3 mg/tube of hemoglobin. Thus, we measured LDH-B4 concentrations in the hemolysate of seven heterozygous individuals deficient in LDH-B subunit activity and eight normal individuals. We could not find a significant difference between the LDH-B4 concentrations in heterozygous and those in normal individuals. These results demonstrate that heterozygous individuals deficient in LDH-B subunit activity produce enzymatically inactive B subunits.

Aspartate Aminotransferases↗
PubMed1998

[Psychopharmacotherapy in pregnancy and lactation. 2: Lactation].

Whilst the incidence of psychiatric disorders decreases during pregnancy, the risk during the postpartum period increases significantly, often leading to the necessity of psychopharmacological intervention during the puerperium, and subsequently during lactation and breast-feeding. The necessity for lithium prophylaxis in manic-depressive women after childbirth has been identified, and it is recommended that weaning rather than omission of psychopharmacological treatment is preferable during the puerperium.

Female↗
PubMed1988

Usefulness of lactate dehydrogenase and lactate dehydrogenase isoenzymes for diagnosis of acute myocardial infarction.

The usefulness of lactate dehydrogenase (LD) and LD isoenzymes in the diagnosis of acute myocardial infarction (AMI) is controversial. The present study reviewed 507 consecutive patients in whom creatine kinase, creatine kinase isoenzymes, LD and LD isoenzymes were ordered over a 1-month period. Of these, 249 had an insufficient number of serial enzyme determinations to establish a laboratory diagnosis of AMI. After excluding an additional 11 patients for other reasons, 247 patients remained for analysis. Of these, only 2 (0.8%) had myocardial infarction by standard clinical criteria with normal creatine kinase and creatine kinase-MB but elevated LD and abnormal LD isoenzymes. Seven patients (7 of 247, 2.8%) had false-positive LD isoenzymes. Thus, the routine use of LD and LD isoenzymes was of no use in most patients (96%) and led to the incorrect diagnosis of AMI more than 3 times as often as it helped with a correct diagnosis. Total 1-month charges for all the LD and LD isoenzymes obtained equalled +42,450. Therefore, it appears that LD and LD isoenzymes are not routinely useful in the diagnosis of AMI and may result in considerable unnecessary expense. It is suggested that LD and LD isoenzymes be ordered only under suspicion of late presentation (greater than 48 hours) of AMI.

Creatine Kinase↗
PubMed1984

Macro lactate dehydrogenase: an LDH-immunoglobulin M complex that inhibits lactate dehydrogenase activity in a patient's serum.

A macro lactate dehydrogenase (LDH, EC 1.1.1.27) isoenzyme with a low total LDH activity was present in the serum of a 57-year-old woman with a drug eruption (cutaneous lesions from an allergic reaction to drug administration). The patient's LDH was shown by immunoelectrophoresis to be bound to immunoglobulin G (IgG) and M (IgM). It was found that the patient's IgM acted as an inhibitor of LDH that was specific for the M subunit. When IgM was treated with 0.1 mol/l of 2-mercaptoethanol (2-ME), the inhibiting effect of the IgM to LDH activity disappeared, while treated IgM continued to bind to the LDH molecule. The LDH activity increased approximately two-fold when the patient's serum was treated with 2-ME. LDH activity in normal human serum was inhibited and an abnormal pattern of LDH isoenzyme appeared when the patient's IgM was added to normal serum. The present case seems to be the first report of LDH-IgM complex with a marked decrease of LDH activity.

Blood Proteins↗
PubMed1996

Age-related responses of right ventricle in swim-trained rats: changes in lactate and pyruvate contents and lactate dehydrogenase activity.

Age related changes in carbohydrate substrates such as, glucose, glycogen, pyruvic acid and lactic acid and the activity of lactate dehydrogenase (LDH) and LDH isoenzyme profile were evaluated in the right ventricle (RV) of swim-trained rats of 6- (adult), 12- (middle-aged) and 18- (old) months-of-age. Moderate hypertrophy was seen in the heart and RV in response to training in all age groups with the 12 months exhibiting a significant increase. While resting levels of pyruvate and glucose in the RV showed small elevations in adult and middle-aged rats, lactic acid showed reductions in all ages. Glycogen supercompensation was seen in the RV of trained animals. These age-related alterations in RV were associated with decreases in blood lactic acid and glucose in the trained rats belonging to all ages. Total protein of the RV decreased with age and exercise increased the content. Total LDH and M4-LDH activities decreased with age. However, training increased their activities in all ages. These changes in the RV suggests that swimming activity produces adaptations (e.g. increased LDH and M4) in all age groups. Considering the degree of adaptations, it can be suggested that adult and middle-aged are suitable for initiating swim-training programs, but not in old age.

Aging↗
PubMed2003

Intramammary pressure in the lactating sow in response to oxytocin and during natural milk ejections throughout lactation.

We developed a simple, non-invasive method to measure the intramammary pressure (IMP) response in sows during natural milk ejection and after i.v. injections of oxytocin. The teats of sows were cannulated and the amplitude and duration of IMP changes were measured via a pressure transducer linked to a computer. During natural milk ejections, the amplitude of the response was 5.5+/-1.8 kPa (mean +/- SD) and the duration of response at half the peak amplitude was 6.8+/-1.6 s. In response to oxytocin a threshold response occurred at 60 mIU oxytocin with no further change up to 200 mIU. The amplitude of the response to an i.v. dose of 60-200 mIU oxytocin (5.5+/-2.2 kPa) and duration (6.4+/-1.7 s) were similar to that during a natural milk ejection. The responses of two galactophorous ducts of a teat measured simultaneously were similar in peak amplitude and duration. When the responses of four glands of a sow were measured simultaneously, there was a lag time in the onset of the IMP peak from the anterior to the posterior glands, and an increase in the peak amplitude from anterior to posterior. Both during natural milk ejections and in response to oxytocin injections, there were significant differences in peak amplitude between sows. We also aimed to determine whether the pressure or duration of milk flow during natural milk ejections was limiting piglet growth rates. IMP of nine sows and the growth rates of their piglets were measured. Both the peak amplitude of IMP response and the growth rate of piglets increased over the course of lactation, but the relationship was not causal. We found that the growth rate of piglets did not depend on IMP amplitude or duration, but we suggest that it may depend on the frequency of suckling and/or the ability of piglets to withdraw milk while it is available.

Animals↗
PubMed1993

Sequence analysis of teleost retina-specific lactate dehydrogenase C: evolutionary implications for the vertebrate lactate dehydrogenase gene family.

At least two gene duplication events have led to the three lactate dehydrogenase (LDH; EC 1.1.1.27) isozymes (LDH-A, LDH-B, and LDH-C) of chordates. The prevailing model for the evolution of the LDH loci involves duplication of a primordial LDH locus near the origin of vertebrates, giving rise to Ldh-A and Ldh-B. A third locus, designated Ldh-C, is expressed in the spermatocytes of mammals and a single family of birds and in the eye or liver tissues of teleost fishes. Ldh-C might have arisen independently in these taxa as duplications of either Ldh-A or Ldh-B. Several authors have challenged this traditional hypothesis on the basis of amino acid sequence and immunological similarity of the three LDH isozymes. They suggest that the primordial LDH gene was duplicated to form Ldh-C and a locus that later gave rise to Ldh-A and Ldh-B. We have differentiated between these hypotheses by determining the cDNA sequence of the retina-specific LDH-C from a teleost, Fundulus heteroclitus. On the basis of amino acid sequence similarity, we conclude that the LDH-C isozymes in fish and mammals are not orthologous but derive from independent gene duplications. Furthermore, our phylogenetic analyses support previous hypotheses that teleost Ldh-C is derived from a duplication of the Ldh-B locus.

Amino Acid Sequence↗
PubMed1977

Utilization of dietary energy for maintenance, milk production and lipogenesis by lactating crossbred cows during their midstage of lactation.

1. Twenty-four energy and nitrogen balances were determined using twenty-four crossbred cows (Brown Swiss X Sahiwal) during their midstage of lactation. Energy balances were estimated by subtracting milk energy and heat production from the metabolizable energy (ME) intake. Heat production was estimated by indirect calorimetry, by collection and analysis of respiratory gases. The cows were given amounts corresponding to 90, 110 and 130% of the ME and 90 and 110% of the digestible crude protein (DCP) standards of the (US) National Research Council (1966). 2. Energy requirements were estimated by partitioning the ME intake for maintenance, milk production and energy gain or loss by multiple regression of energy balance values. Heat production (and thus energy balance) was corrected for excess N intake. 3. Energy requirements for maintenance were 585-18, 580-17 and 574-41 kJ ME/kg body-weight0.75 per d for cows in negative balance, cows in positive balance and for all cows, respectively. 4. The efficiency of utilization of ME for milk production was 68-52, 65-48 and 66-12% respectively, for cows in negative balance, for cows in positive balance and all cows. Energy required per kg fat-corrected milk production was 4-580, 4-791 and 4-746 MJ ME for the respective groups of cows. 5. The efficiency of utilization of ME for tissue gain was 67-67 and 64-86% for cows in positive balance and for all cows respectively.

Animals↗
PubMed1981

[Nitrogen balance and nitrogen utilization of non-lactating and lactating cows under various feeding frequency conditions].

A cross-over trial with nine nonlactating nonpregnant cows (experiment I) and a single-reversal trial with eight lactating cows (experiment II) were conducted to study the effect of feeding frequency upon nitrogen balance. The three treatments in experiment I were twice daily forage and concentrate, twice forage and eight times concentrate, and ten times forage and concentrate per day. In experiment II the animals received their forage and concentrate in two equal feedings daily or the forage in two and the concentrate in six meals per day. The diets had a severely restricted crude fiber content of only 16% in the dry matter of the total ration. In experiment I feeding frequency had no effect on fecal or urinary nitrogen excretion, nitrogen retention and nitrogen utilization. In experiment II, the urinary nitrogen excretion was significantly decreased by 9% in response to feeding concentrate six times daily. Fecal and milk nitrogen excretion as well as nitrogen retention and utilization criteria, however, were not significantly different for the two feeding frequencies.

Animals↗
PubMed1982

H-2-controlled suppression of T cell response to lactate dehydrogenase B. Characterization of the lactate dehydrogenase B suppressor pathway.

We characterized the cell types involved in the H-2-controlled suppression of T cell response to lactate dehydrogenase B (LDHB). The suppressor effector (Tse) was found to be an Lyt-1+2+, J+ cell that recognizes antigen together with Ek molecules of antigen-presenting cells (APC). To become functional, the Tse cell requires a second signal from a nonspecific, Lyt-1+2-, J+ suppressor-inducer (Tsi) cell. The Tsi-Tse interaction is not subject to any genetic restriction. The target cell of suppression is an Lyt-1+2-, J- (most likely T helper [Th]) cell that recognizes LDHB in the context of A molecules on APC. The suppression is manifested in inhibition of the antigen-specific, A-restricted proliferation of Th cells. The interaction between Tse and Th is restricted by the A region of the H-2 complex. Because this restriction is determined by the receptor of Th cells, the mechanism of Th-Tse interaction most likely involves a concomitant recognition of LDHB and A region-controlled molecules by Th cells on the surface of Tse cells.

Animals↗
PubMed2004

Tissue manganese concentrations in lactating rats and their offspring following combined in utero and lactation exposure to inhaled manganese sulfate.

There is little information regarding the tissue distribution of manganese in neonates following inhalation. This study determined tissue manganese concentrations in lactating CD rats and their offspring following manganese sulfate (MnSO4) aerosol inhalation. Except for the period of parturition, dams and their offspring were exposed to air or MnSO4 (0.05, 0.5, or 1 mg Mn/m3) for 6 h/day, 7 days/week starting 28 days prior to breeding through postnatal day (PND) 18. Despite increased manganese concentrations in several maternal tissues, MnSO4 inhalation exposure did not affect body weight gain, terminal (PND 18) body weight, or organ weights in the dams. Exposure to MnSO4 at 1 mg Mn/m3 resulted in decreased pup body weights on PND 19 and decreased brain weights in some PND 14 to PND 45 pups. Exposure to MnSO4 at > or =0.05 mg Mn/m3 was associated with increased stomach content, blood, liver, and skull cap manganese concentrations in PND 1 pups, increased brain, lung, and femur manganese concentrations in PND 14 pups, and elevated olfactory bulb, cerebellum, and striatum manganese concentrations in PND 19 pups. When compared to controls, MnSO4 exposure to > or =0.5 mg Mn/m3 increased liver and blood manganese concentrations in PND 14 pups and increased liver, pancreas, and femur manganese concentrations in PND 19 pups. Manganese concentrations returned to control values in all offspring tissues by PND 45 +/- 1. Our data demonstrate that neonatal tissue manganese concentrations observed following MnSO4 inhalation are dependent on the MnSO4 exposure concentration and the age of the animal.

Administration, Inhalation↗
PubMed1992

Selenium and human lactation in Australia: milk and blood selenium levels in lactating women, and selenium intakes of their breast-fed infants.

A series of 20 mother-infant pairs were studied in Brisbane, Australia, at 6-12 weeks postpartum. The mean selenium concentration in maternal blood was 101 (SD +/- 19) ng/g and in maternal serum 81(+/- 15) ng/g; serum values appeared low in comparison with those reported for lactating women from Japan and the USA, but similar to those from Finland and from a previous Australian study. Breast milk selenium concentrations (11.9 +/- 3.5 ng/g) were also low by international standards, but not as low as in New Zealand or Scandinavia. There was no correlation between selenium concentrations in milk and blood (or serum). The infants' 24-h breast-milk intakes were 856 +/- 172 g, and their 24-h selenium intakes 10.7 +/- 4.1 micrograms (compared to the Australian RDI of 10 micrograms).

Adolescent↗
PubMed1985

Lactate dehydrogenase from Streptococcus mutans: purification, characterization, and crossed antigenicity with lactate dehydrogenases from Lactobacillus casei, Actinomyces viscosus, and Streptococcus sanguis.

A cytoplasmic fructose-1,6-diphosphate-dependent lactate dehydrogenase (LDH; EC 1.1.1.27) from Streptococcus mutans OMZ175 was purified to homogeneity as judged by sodium dodecyl sulfate-gel electrophoresis. The purification consisted of ammonium sulfate precipitation of the cytoplasmic fraction, DEAE-Sephacel and Blue-Sepharose CL.6B chromatography, and Sephacryl S200 gel permeation. The catalytic activity of the purified enzyme required the presence of fructose-1,6-diphosphate with a broad optimum between pH 5 and 6.2. The concentration of fructose-1,6-diphosphate required for half-maximal velocity was around 0.02 mM and was affected by the pyruvate concentration. The enzyme seemed to have at least two binding sites for the activator which interact in a cooperative manner. Increasing concentrations of fructose-1,6-diphosphate up to 2 mM enhanced the relative affinity of the enzyme for pyruvate and modified the pyruvate saturation curve from sigmoidal to hyperbolic. The enzyme activity showed also a sigmoidal response to NADH, exhibiting two binding sites for the cofactor with a Hill coefficient of about 1.9. The molecular weight of the native enzyme was 150,000 as determined by gel permeation on Sephacryl S200. Monomers (38,000 daltons) and dimers (85,000 daltons) were observed by sodium dodecyl sulfate-gel electrophoresis; the latter form was dissociated after reduction with 2-mercaptoethanol, and the enzyme could be considered a tetramer. Antibodies obtained against the purified S. mutans OMZ175 LDH cross-reacted with the sodium dodecyl sulfate-dissociated forms of LDHs from different S. mutans serotypes, Streptococcus sanguis OMZ9, Lactobacillus casei ATCC 4646, and Actinomyces viscosus NY 1. A competitive enzyme-linked immunosorbent assay allowed us to detect a very close relationship between the native states of L-LDHs from S. mutans serotypes and S. sanguis. Cross-reactions were also observed with the LDHs from A. viscosus and L. casei, the latter being the least related. A very weak immunological relationship was obtained between the L-LDH from S. mutans OMZ175 and the D-LDH from Lactobacillus leichmannii, whereas no cross-reaction could be detected with mammal LDHs.

Actinomyces↗
PubMed1997

Lactational headache: a lactation consultant's diary.

There are few references to lactational cephalalgia (headache) in the literature, and these few such headaches are attributed to oxytocin surges associated with the milk-ejection reflex. The case described here differs, in that the apparent trigger was overfulness, rather than an oxytocin surge, that occurred when the infant began sleeping through the night or after a missed, delayed, or partial feed. Headaches were relieved by putting the baby to the breast and the resultant milk-ejection reflex. This case study describes maternal coping strategies from 5 months postpartum until weaning was completed at 12 months.

Adaptation, Psychological↗
PubMed1990

Structure and function of L-lactate dehydrogenases from thermophilic, mesophilic and psychrophilic bacteria, IX. Identification, isolation and nucleotide sequence of two L-lactate dehydrogenase genes of the psychrophilic bacterium Bacillus psychrosaccharolyticus.

Two genes encoding for L-lactate dehydrogenase (LDH) from the psychrophilic bacterium Bacillus psychrosaccharolyticus (DSM 6) were cloned and their nucleotide sequence determined using a pEMBL vector and gene hybridization probes. The deduced amino-acid sequence of the gene from clone pLDH(X), which is located on a 5.87-kb HindIII-fragment, shows an identity of 86% as compared with the sequence of the wildtype LDH(P) from B. psychrosaccharolyticus and consists of 319 amino acids. Clone pLDH(P) contained a gene on a 4-kb HindIII-EcoRI fragment, of which the amino-acid sequence is identical with the enzyme isolated from B. psychrosaccharolyticus. The nucleotide sequences of LDH(P) and LDH(X) show 77% identity. Both genes are expressed in E. coli and the proteins could be isolated as shown by enzyme activity tests and determination of the N-terminal amino-acid sequence. However no expression of LDH(X) could be detected in B. psychrosaccharolyticus itself under the conditions chosen for oxygen induction of LDH. The function of the additional, non-expressed enzyme is not known.

Amino Acid Sequence↗
PubMed1990

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria, X. Analysis of structural elements responsible for the differences in thermostability and activation by fructose 1,6-bisphosphate in the lactate dehydrogenases from B. stearothermophilus and B. caldolyticus by protein engineering.

The amino-acid sequences of the lactate dehydrogenases (LDH) from B. stearothermophilus and B. caldolyticus differ at only 10 positions. The properties of these enzymes however show substantial differences. The LDH from B. stearothermophilus is activated by Fru-P2 and has a higher thermostability (10 degrees C) than the enzyme from B. caldolyticus which cannot be activated by Fru-P2. To correlate these functional differences to the structural properties, we have constructed a set of hybrid- and point-mutants of the two LDHs. The amino acids at positions 207, 209B, and 209C could be identified to confer the property of activation by Fru-P2 to the enzymes. This part of the enzyme is to a large extent also responsible for the different thermostabilities of these two proteins.

Amino Acid Sequence↗
PubMed1991

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria, XI. Engineering thermostability and activity of lactate dehydrogenases from bacilli.

An extensive comparative structural analysis of lactate dehydrogenase (LDH) sequences from thermophilic, mesophilic and psychrophilic bacilli revealed characteristic primary structural differences. These specific amino-acid substitutions were found in the entire LDH molecule. However, in certain regions of the LDH an accumulation of these exchanges could be detected. These regions seem to be particularly important for the temperature adaptation of the enzyme. The influence of one of such regions at the N-terminus on stability and activity of LDHs was analysed by the construction of hybrid mutants between LDH sequences from thermophilic, mesophilic and psychrophilic bacilli and also by site-directed mutagenesis experiments at five different positions. The substitutions of Thr-29 or Ser-39 to Ala residues in the LDH from the mesophilic B. megaterium increased the thermostability of the enzyme drastically (15 degrees C). An increase of 20 degrees C could be observed when both amino-acid substitutions were introduced. These amino-acid substitutions resulted in an increase of Km for pyruvate and led to a three-fold reduction of the activity (kcat/Km) at 40 degrees C compared with the wild type enzyme. The influence of these amino-acid substitutions was also investigated in the LDHs from thermophilic and psychrophilic bacilli. The high heat resistance of the LDH from the thermophilic B. stearothermophilus was not altered by the Ala to Thr and Ser substitutions at positions 29 and 39, respectively. This indicates a cooperatively stabilized conformation of this LDH. However, in this mutant of the B. stearothermophilus LDH the activity (kcat/Km) was increased two-fold.

Amino Acid Sequence↗
PubMed1986

Embryo development and zona-shedding in the ligated oviduct and contralateral uterine horn of non-lactating and lactating Mongolian gerbils (Meriones unguiculatus).

Within the same female, concurrent lactation had no apparent effect on the development and hatching of embryos artificially retained in the oviduct while effectively inhibiting zona shedding and implantation in the contralateral uterine horn. This result is believed due to a specific inhibitor(s) present in the uterine fluid or to physical constriction by the uterus. These extrinsic, maternal factors act either singly or in combination to influence the mature blastocyst.

Animals↗