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PubMed2006

Longitudinal non-invasive proton NMR spectroscopy measurement of vitreous lactate in a rabbit model of ocular hypertension.

To determine whether vitreous lactate concentrations are correlated with intraocular pressure (IOP) rise, retinal ganglion cell (RGC) damage, and nerve fiber layer (NFL) thickness decrease in a rabbit model of ocular hypertension. Also, to learn whether proton nuclear magnetic resonance ((1)H-NMR) spectroscopy can provide sequential, non-invasive in vivo measurements of vitreous lactate. Intra-anterior chamber injections of 20-mum latex beads were used to impede aqueous drainage in New Zealand White rabbits, causing an elevation of IOP. Group I consisted of 12 rabbits in which unilateral elevations in IOP were achieved. Group II consisted of 6 rabbits in which treatment did not cause a change in IOP. The contralateral eye served as a control in both groups. Control eyes received an equal volume injection of vehicle only. IOP was measured for two pre-treatment days and then on post-treatment days 1, 3, 5, 7, 9, 16, 23, 30, and 37. (1)H-NMR spectroscopy was used to measure changes in vitreous lactate concentrations that may be associated with the onset and progression of the pathophysiology. Post-mortem histochemical analysis at the light microscope level was used to quantify changes in the retinal NFL thickness and in the numbers of RGC, and correlate them with IOP and percent change in lactate levels. Baseline IOP in Group I control and treated eyes were 12.0+/-1.9 and 12.5+/-1.3 mmHg, respectively. Between days 5 and 9 post-treatment, the IOP in Group I treated eyes (n=12) rose to 23.9+/-4.2 mmHg. IOP in the control eyes remained unchanged (12.0+/-1.6). Vitreous lactate levels in Group I treated eyes increased by 100%, from pre-treatment values. Levels in control eyes remained unchanged. In Group I, IOP and percent change in lactate concentration in treated eyes were closely correlated throughout the study period (r=0.95; p< or =0.05). Group II control and treated eyes showed no significant changes in either IOP or lactate. Group I treated eyes had a reduced NFL thickness (65+/- 4 microm; n=5) at the temporal medullary ray (MR) compared with control eyes (45+/-6 microm). A smaller reduction was found in the nasal MR areas, where thickness was 53+/-3 microm in treated eyes and 66+/-4 microm in control eyes. RGC numbers also were decreased in the treated eyes (241,222+/-10,920 cells) vs. 322,311+/-8726 cells in control eyes. TdT-mediated dUTP nick-end labeling (TUNEL) indicated that RGC loss in the treated eyes was most likely due to apoptosis. In vivo changes in lactate can be monitored non-invasively over time using (1)H-NMR spectroscopy. Vitreous lactate concentrations increased and returned to baseline concurrently with IOP. The brief elevation in IOP produced a reduction in both the RGC cell numbers and in the thickness of the NFL.

Animals↗
PubMed2004

The effect of lactate addition on the growth of Penicillium camembertii on glutamate.

The effect of an additional carbon source, lactate, on Penicillium camembertii growth on glutamate as both carbon and nitrogen sources was examined. Glutamate (and lactate) was present in excess in both media. Throughout the whole culture, similar growth time-courses were recorded on both media, indicating the absence of a lactate effect on growth. During the first part of growth, corresponding to an increasing amount of viable biomass, the rate of glutamate consumption remained high, as well as the related ammonium production, indicating its use as a carbon source in addition to being nitrogen source. The low growth rates recorded during the last part of growth resulted in low glutamate consumption, while lactate consumption continued mainly by a maintenance mechanism for the energy supply. A clear differentiation appeared therefore between the carbon source and the energy source: glutamate was mainly used as C source (and N source) for biosynthesis, while lactate was mainly assimilated for energy supply. Carbon and nitrogen yield examinations confirmed this result. Indeed, the C/N ratio found for P. camembertii cellular material (8.14) was about twice that of glutamate (4.29). From this, about half of the available nitrogen was used for biomass formation during growth on glutamate-lactate based medium, as experimentally confirmed (constant yield nitrogen from biomass on nitrogen from glutamate was found (0.49), while the excess nitrogen was released as ammonium). The constant and close to unit (0.99) yield carbon from CO2 on carbon from lactate, also recorded during growth on glutamate-lactate based medium, confirmed that lactate was mainly used as an energy source.

Carbon↗
PubMed2005

Pleiotropic effects of lactate dehydrogenase inactivation in Lactobacillus casei.

In lactic acid bacteria, conversion of pyruvic to lactic acid through the activity of lactate dehydrogenase (Ldh) constitutes the final step of the homofermentative pathway. Lactobacillus casei has two characterized genes encoding Ldh activities. The ldhL gene codes for an L-Ldh, which specifically catalyzes the formation of L-lactate, whereas the hicD gene codes for a D-hydroxyisocaproate dehydrogenase (HicDH), which catalyzes the conversion of pyruvate into D-lactate. In L. casei cells fermenting glucose, a mixture of L-/D-lactate with a 97:3% ratio was formed. Inactivation of hicD led to undetectable D-lactate levels after glucose fermentation, while L-lactate levels remained constant. Inactivation of ldhL did not abolish the production of L-lactate, but the lactate final concentration decreased about 25% compared to the wild type, suggesting the presence of at least a second L-Ldh. Moreover, part of the pyruvate flux was rerouted and half of the lactate produced was in the D-isomer form. ldhL inactivation in L. casei showed additional interesting effects. First, the glycolytic flux from pyruvate to lactate was redirected and other fermentation products, including acetate, acetoin, pyruvate, ethanol, diacetyl, mannitol and CO(2), were produced. Second, a lack of carbon catabolite repression of lactose metabolism and N-acetyl-glucosaminidase activity was observed. This second effect could be partly avoided by growing the cells under aeration, since NADH oxidases could account for NAD+ regeneration.

Acetates↗
PubMed2005

Antirheumatic drugs in pregnancy and lactation.

OBJECTIVE: To review the toxicity issues of commonly used antirheumatic drugs in pregnancy and lactation. METHODS: A review of the medical literature using Medline database via Ovid was performed to identify the toxicities of antirheumatic drugs in pregnancy and lactation. RESULTS: Many rheumatologic diseases in women often first present during the childbearing years. In most cases, antirheumatic therapy is required for their disease control. Glucocorticoids may be used during pregnancy; however, first-trimester use should be avoided if possible and breastfeeding should occur 4 hours after the last dosing. Nonsteroidal antiinflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors should be discontinued 6 to 8 weeks before delivery. NSAIDs are compatible with lactation, although there is potential risk of jaundice and kernicterus. There is insufficient data on COX-2 inhibitors and lactation. Hydroxychloroquine and sulfasalazine may be continued throughout pregnancy and lactation. Methotrexate and leflunomide are contraindicated during pregnancy and lactation. Cyclophosphamide and mycophenolate mofetil should be avoided during pregnancy and lactation. Azathioprine and cyclosporine A could be used with caution during pregnancy if felt there is a need to suppress disease activity. They are not compatible with breastfeeding. There are insufficient data regarding tumor necrosis factor-antagonists, anakinra, and rituximab in relation to pregnancy and lactation. Male patients should be made aware of the effects methotrexate, leflunomide, sulfasalazine, and cyclophosphamide may have on their fertility. CONCLUSIONS: Health care providers should discuss the risks and benefits of antirheumatic therapy during conception, pregnancy, and lactation with their patients. Better maternal and fetal outcomes can be expected if the pregnancy is planned, the rheumatic disease is stable, and if appropriate medication adjustments can be made ahead of time.

Antirheumatic Agents↗
PubMed1997

The effect of lactation on induced Fos-like immunoreactivity in the rat hypothalamic paraventricular nucleus.

Lactating rats display a period of blunted hypothalamo-pituitary-adrenal (HPA) response to a variety of stressors. This hyporesponsiveness is reported to be dependent upon continuous mother-pup interactions. In this study, computer-assisted densitometric methods were used to measure levels of induced Fos-like immunoreactivity (FLI) in the hypothalamic paraventricular nucleus (PVN) of lactating and non-lactating rats. Adrenalectomy (ADX) induces elevated levels of FLI in the PVN of non-lactating rats. We have observed that, between post-partum day (pd) 4 and pd 21, the level of ADX-induced FLI in the PVN of lactating rats follows a U-shaped distribution; that the persistence of this phenomenon is dependent upon continued mother-pup interaction and that sustained mother-pup interaction beyond the end of the normal suckling period (pd 21) does not extend the period of refractoriness. We have further determined that both the non-specific neural activator Metrazole, and the glutamate agonist N-methyl-D,L-aspartate (NMA), induced smaller increases in FLI in the PVN of lactating rats compared to non-lactating cohorts, and that the suppressing effect of lactation on Metrazole-induced FLI does not extend to all brain regions. These results suggest that mechanisms responsible for the onset and maintenance of the so-called lactational stress-hyporesponsive period (LSHRP) include altered function of glutamatergic pathways.

Adrenalectomy↗
PubMedDate not supplied

Distribution of lactate in plasma and erythrocytes during and after exercise in horses.

The distribution of lactate between red blood cells (RBC) and plasma was examined at rest, during exercise and 30 min after exercise in six Standardbred horses. Lactate and water concentrations were measured in blood and plasma samples collected prior to exercise, during the last 15 s of each step of an incremental exercise test and at 5 min intervals during the first 30 min after exercise. The mean ratio of RBC lactate concentration (RBCLa) to plasma lactate concentration (PLa) prior to exercise was 1.02 +/- 0.34. Haemoconcentration during exercise was associated with more rapid accumulation of lactate in plasma than in RBCs. Mean whole blood lactate concentration (BLa) was only 59% of PLa in samples collected during exercise. BLa was highly correlated with PLa during exercise (r = 0.98; P < 0.001), but individual PLa values differed from predicted BLa values by up to 2.1 mmol l-1 when PLa exceeded 8 mmol l-1. At each exercise speed and time after exercise there was a large variation between horses in the ratio of BLa/PLa. During exercise at 11 m s-1 the ratio ranged from 0.46-0.73. The BLa/PLa ratio was significantly correlated with increasing exercise intensity, (r = -0.68, P < 0.001) and with haematocrit, (r = -0.69, P < 0.001). The effects of PLa and haematocrit on the BLa/PLa ratio during exercise and the post-exercise period varied greatly between horses. The ratio of lactate concentrations in water of RBCs and plasma varied greatly during and after exercise (0.61-1.22). The ratio also varied considerably between horses, with coefficients of variation ranging from 14-34%. Lactate concentrations in RBC and plasma water vary greatly between horses during and after exercise. We concluded that lactate is unevenly distributed between red blood cells and plasma in blood samples centrifuged immediately after collection, and the variability depends on haematocrit.

Animals↗
PubMed1998

Lumbar bone mineral density changes during pregnancy and lactation.

OBJECTIVE: To elucidate the change of bone metabolism in the lumbar trabecular and its relationship with serum hormonal changes in pregnancy and lactation. STUDY DESIGN: In a cross-sectional study, we measured the bone mineral density (BMD) of 2-4 lumbar vertebrae of 571 puerperae at days 3-5 postpartum and 341 healthy, non-pregnant women (control subjects) of approximately the same age by dual energy X-ray absorptiometry. In a longitudinal study, we also measured the BMD of 111 puerperae at 3 and 6 months after delivery. RESULTS: The mean BMD at days 3-5 postpartum was significantly lower than that of the control (1.013+/-0.005 vs. 1.032+/-0.006 g/cm2, P = 0.019). The lactating group showed BMD decrement to 95.1+/-0.5% (n = 69) and 94.1+/-0.7% (n = 61) at 3 and 6 months postpartum, respectively, compared with days 3-5 postpartum, and the amenorrhea group showed the same tendency. The non-lactating group and resumption of menses group did not show a BMD decrement postpartum. In the lactating group, serum estradiol was significantly lower than in the non-lactating group at 3 months postpartum, serum prolactin and bone alkaline phosphatase levels were higher than in the non-lactating group at 3 and 6 months postpartum. CONCLUSIONS: Pregnancy may cause a decrease of lumbar BMD, and the lactation and amenorrhea also cause a decrease of BMD. In addition to lactation status, the ovarian dysfunction is one of the factors in bone loss during lactation.

Absorptiometry, Photon↗
PubMed1982

Serum lactate dehydrogenase and its isoenzymes in men with maldescended testes.

Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were determined as a screen for testicular germ cell neoplasia in 130 men with maldescended testes. A testicular tumor was found on clinical examination in 1 patient, which was revealed to be embryonal carcinoma, teratoma, yolk sac tumor and carcinoma in situ on orchiectomy. Subclinical testicular germ cell neoplasia was found on testicular biopsy in 3 men (1 with microinvasive seminoma and 2 with carcinoma in situ). These 4 patients had normal serum lactate dehydrogenase and serum lactate dehydrogenase isoenzymes. Elevated serum lactate dehydrogenase was noted in 3 men without testicular germ cell neoplasia: 1 had predominantly increased serum lactate dehydrogenase isoenzymes 1 to 3 and 2 had slightly increased serum lactate dehydrogenase isoenzymes 3 and 4. Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were not sensitive to detect testicular germ cell tumors in a subclinical stage.

Cryptorchidism↗
PubMed2003

Effects of maternal ethanol consumption during pregnancy or lactation on intestinal absorption of folic acid in suckling rats.

A fostering/crossfostering analysis of the effects of maternal ethanol exposure on jejunal and ileal folate absorption was performed. Male and female rats were randomized into two groups. In the first group, ethanol-treated rats received ad libitum 5, 10 and 15% ethanol in the drinking fluid during three successive weeks. A consumption of 20% was maintained in this group for 5 additional weeks. Ethanol-treated rats were mated. Group 2 served as the control. To study the effect of chronic alcoholism during lactation or gestation separately, at birth (2nd day postpartum) control newborns were cross-fostered to ethanol dams (EG), and the pups issued from the ethanol treated mothers were cross-fostered to control dams (CG). Thus, three experimental groups of pups were formed: (1) control pups receiving no treatment during gestation and lactation (CG); (2) pups exposed to ethanol only during gestation (GG); and (3) pups exposed to ethanol only during lactation (LG). At 21 days postpartum the jejunal and distal ileum folate absorption was determined in the offspring rats by a perfusion technique. Milk folic acid levels were determined by an immunoluminometric assay. The results showed an increase in jejunal folic acid absorption in offsprings exposed to ethanol only during the lactation period (LG). However, in pups exposed to ethanol only during the gestation period (GG), the jejunal folic acid absorption was significantly increased only at concentrations of 0.25, 0.5 and 2.5 microM. No free folic acid absorption occurred in the distal ileum of control pups (CG) at day 21 at all assayed concentrations but in offsprings exposed to ethanol only during the gestation or lactation periods absorption did take place. Pups exposed to ethanol during the gestation period (GG) showed decreased values in ileum folic acid absorption at the lowest assayed concentration (0.25 microM) compared to values obtained for pups exposed to ethanol only during lactation (LG). Milk folic acid levels were significantly decreased in the ethanol-fed dams on day 21 of lactation. These results indicate that exposure of rats to ethanol during the lactation period affects more severely postnatal development of intestinal functions than ethanol exposure only during gestation. In summary, both the exposure to ethanol itself and the decrease in folic acid intake caused alterations in the function of the intestinal mucosa in the offspring, which in turn altered absorption time and development. However, the present results do not explain how ethanol stimulated intestinal absorption of folic acid in pups exposed to ethanol during the gestation or lactation periods. Further studies are needed.

Administration, Oral↗
PubMed1996

Glucose and lactate kinetics during a short exercise bout in pregnancy.

Pregnancy is considered diabetogenic. Although exercise has been advocated to assist in metabolic control of the nonpregnant diabetic individual, there is a paucity of data about the metabolic effects of exercise during pregnancy. To examine whether moderate exertion may be beneficial in the maintenance of maternal carbohydrate homeostasis, glucose and lactate kinetics were measured in the third trimester in five pregnant nondiabetic women (gestational age, 34.2 +/- 0.1 weeks [mean +/- SE]) by infusion of 45 microg x kg(-1) x min(-1) [6,6-2H2]glucose and 70 microg x kg(-1) x min(-1) [U-13C]lactate tracers. Subjects were observed at rest for determination of baseline steady-state kinetics over a 30-minute period, and then they exercised for 30 minutes at 60% maximum oxygen consumption (VO2max) and were evaluated for 30 minutes postexercise. Glucose and lactate kinetics and lactate oxidation were measured throughout the exercise protocol. This study was repeated postpartum in all individuals at least 6 weeks after delivery. Compared with the steady-state preinfusion period, plasma glucose concentration was not elevated during exercise in either group, nor was plasma lactate concentration significantly different in either group. Glucose kinetics did not change during exercise, but lactate kinetics increased in both groups. V02 and percent of lactate C contribution to CO2, an indication of lactate oxidation, increased proportionally in both groups during exercise. Metabolic perturbations, as measured by glucose and lactate kinetics, do not appear to be different during the third trimester of pregnancy during a relatively short bout of exercise compared with the nonpregnant state.

Adult↗
PubMed1999

Effect of lactate dehydrogenase activity and isoenzyme localization in bovine oocytes and utilization of oxidative substrates on in vitro maturation.

Oocyte nutritional metabolism changes during maturation in order to increase the energy available to support metabolic requirements. The aim of this work was to study pyruvate and lactate utilization as oxidative substrates on IVM and lactate dehydrogenase (LDH) activity and localization of their isoenzymes in bovine oocytes. Immature cumulus-oocyte complexes (COCs) were recovered by aspiration of antral follicles in ovaries obtained from slaughtered cows. The COCs and denuded oocytes were separately cultured in TCM-199 with steer serum (controls) and were supplemented with pyruvate, lactate or lactate plus NAD for 24 h at 39 degrees C in 5% CO2:95% humidified air. No significant differences were found in IVM rates of COCs matured according to the various treatments (P>0.05). The IVM rate in denuded oocytes without supplementation was 47.8%. The presence of pyruvate in the culture medium resulted in an increased number of matured denuded oocytes (59.4%; P<0.05), but the addition of lactate failed to improve the IVM rate of matured denuded oocytes (47.6%, P>0.05). When the medium was supplemented with lactate plus NAD, the IVM rate of denuded oocytes likewise failed to differ from that obtained with the addition of pyruvate (59.9%, P>0.05). The LDH activity in immature and matured COCs and denuded oocytes was (3.1+/-1.6) 10(-3), (3.3+/-1.6) 10(-3) U/COC, (5.2+/-2.0) 10(-5), (5.4+/-3.5) 10(-5) U/oocyte with pyruvate as substrate, and (1.2+/-0.5) 10(-3), (1.0+/-0.5) 10(-3) U/COC, (2.2+/-0.1) 10(-5), (2.5+/-1.4) 10(-5) U/oocyte respectively, with lactate; no significant differences due to maturation status were observed (P>0.05; n = 9 for each LDH activity). Electrophoresis disclosed that the principal band corresponded to the LDH-1 isoenzyme in oocytes, while there was no predominance of any isoenzyme in cumulus cells. Due to the fact that LDH-1 is the main oocyte isoenzyme, the pyruvate used during oocyte maturation could be partly produced from lactate when the NAD supply is adequate. Cumulus cells would be responsible for providing pyruvate and/or lactate as oxidative substrates to be used by the bovine oocyte and this supply would be regulated by the LDH activity in these cells.

Animals↗
PubMedDate not supplied

Lactate carriers in the artificially perfused human term placenta.

Thirty-two isolated cotyledons from human term placentae were perfused artificially with a tissue culture medium on the maternal and the fetal side. The transfer and uptake of labelled L-lactate and D-lactate (test substance) relative to L-glucose (reference substance, extracellular marker) were investigated in steady-state experiments (n = 9) and in a single passage paired tracer dilution technique (n = 23). The L-lactate transfer exceeded the L-glucose transfer two to three times. The L-lactate uptake into the trophoblast--both from the maternal and the fetal side--was more than three times that of D-lactate. L-lactate transfer and uptake were inhibited by phloretin. The L-lactate transfer showed a saturation kinetic at increasing chemical concentrations of lactate. It is concluded that lactate carriers exist both in the maternal and fetal side of the trophoblast.

Diffusion↗
PubMedDate not supplied

Lactate transfer across the perfused human placenta.

The transfer of lactate across the human placenta was investigated using an in vitro dually-perfused placental preparation. Using a novel technique, the unidirectional flux of L-lactate was found to be linearly dependent on L-lactate concentration. In addition, unidirectional transfer rates were found to be the same in both maternal-to-fetal and fetal-to-maternal directions at the same lactate concentration. Transfer of [14C]L-lactate was decreased by approximately 15 per cent in competition with unlabelled L-lactate. Stereospecificity and permeability experiments demonstrated the existence of a transfer mechanism which could distinguish between the L- and D-isomers of lactate. Our data suggest that, while a stereospecific carrier for lactate exists in the perfused placenta, the bulk of transplacental lactate transfer takes place by non-carrier-mediated diffusion.

Antipyrine↗
PubMed1996

Lactation and pregnancy effects on blood flow to mammary and reproductive systems in heat-stressed rabbits.

This study used radioactive microspheres to examine blood flow distribution in the mammary and reproductive systems of hyperthermic (+1 degrees C), anesthetized laboratory rabbits at different stages of pregnancy and lactation. Ovarian, cervical and oviductal blood flows decreased by 20-30% during heat stress while vulval blood flow rose by 40%, irrespective of pregnancy and/or lactation status. Mammary blood flow was unaltered during heat stress at most pregnancy and/or lactation stages, with the exception of a 35% decrease in non-pregnant rabbits in early lactation. Uterine blood flow in non-pregnant rabbits in early and peak lactation decreased by 42% and rose by 33%, respectively. Uterine blood flow response to heat stress in pregnant animals varied among tissues: no changes occurred in the flow to implantation sites (early pregnancy) or to inter-embryonic segments (mid- to late pregnancy); that to gestation sacs decreased by 12-40% at the different lactation stages; and that to maternal placentas decreased in the lactating state by 18%, and rose in the non-lactating state by 50%. Results indicate that pregnancy and lactation modulate vasomotor responses to heat stress in mammary and reproductive tissues, and that the extent of the modulation depends upon their respective stages.

Animals↗
PubMed1998

Mesotocin receptors during pregnancy, parturition and lactation in the tammar wallaby.

Mestocin receptor concentrations in membrane preparations from reproductive tissues of the tammar Macropus eugenii throughout gestation and lactation were assessed using [3H]-oxytocin as the ligand. There was a single binding site which bound both mesotocin and oxytocin with high and similar affinities. Mesotocin receptor concentrations in the myometrium were low (708 +/- 199 fmol mg-1 protein) in early and middle gestation but increased significantly on day 23 of pregnancy of the 26-day gestation period to 1921 +/- 552 fmol mg-1 protein. Myometrial receptors reached a peak of 2483 +/- 575 fmol mg-1 protein on days 25 and 26 of gestation, but returned to basal levels about an hour after birth. Receptor concentrations in the contralateral non-gravid uterus were much lower (605 +/- 75 fmol mg-1) and did not significantly increase throughout the period of gestation but dropped one day before birth. Mesotocin receptors were undetectable in the endometrium, the yolk sac placenta and the lateral, median and anterior vagina of all animals tested. In the lactating mammary gland after birth mesotocin receptors were initially high (588 +/- 38 fmol mg-1) but decreased after 200 days and by late lactation were 224 +/- 55 fmol mg-1 protein on day 240, close to the time of weaning. Mesotocin receptors in the ipsilateral non-lactating gland were also high in early lactation (430 +/- 153 fmol mg-1) and declined in late lactation (62 +/- 20 fmol mg-1). The changing concentrations of mesotocin receptors in pregnancy and lactation demonstrate that they are specifically regulated in tammar reproductive tissues. The increase in mesotocin receptors in gravid, but not in the non-gravid myometrium three days before birth may make the uterus responsive to the surge of mesotocin at birth. Since this rise is unilateral and only occurs in the gravid myometrium it must be due to local effects from the ipsilateral ovary or the feto-placental unit. Likewise, the down-regulation of mesotocin receptors in the contralateral, non-gravid myometrium may be due to its proximity to the developing follicle. The changing concentrations in the lactating and the adjacent, non-lactating mammary gland also reflect a differential regulation of mesotocin receptors, probably mediated via the sucking stimulus. Thus, local influences appear to be of primary importance in the regulation of mesotocin receptors during reproduction in this marsupial.

Animals↗
PubMed1985

Lactate metabolism in acute myocardial infarction and its relation to regional ventricular performance.

Myocardial metabolism was assessed in 20 patients with acute anterior myocardial infarction using lactate uptake (defined as (aortic lactate - great cardiac venous lactate)/aortic lactate X 100) as an index. The regional ejection fraction of the anterior wall was obtained from left ventriculography. There was a linear relation between lactate uptake and regional ejection fraction (r = 0.79, p less than 0.001). Four patients without total occlusion in the infarct vessel had a higher lactate uptake (19.6 +/- 6.7 versus 4.2 +/- 13.4%, p less than 0.05) and regional ejection fraction (26.3 +/- 7.9 versus 14.9 +/- 7.0%, p less than 0.05) than did 16 patients with total occlusion. The latter group of patients underwent intracoronary infusion of urokinase, which resulted in reperfusion in 13 patients. Lactate uptake before urokinase infusion (sample I), just after reperfusion (sample II), 30 minutes after reperfusion (sample III) and 4 weeks after reperfusion (sample IV) was 5.7 +/- 13.2, -13.9 +/- 14.7, 2.9 +/- 15.2 and 20.2 +/- 11.0%, respectively (sample I versus II and II versus III, p less than 0.01; sample I versus IV and III versus IV, p less than 0.05). The decrease in lactate uptake immediately after reperfusion, which was accompanied by an increase in creatine kinase-MB isoenzyme release into the blood, was considered to be the result of a "washout" effect. Lactate uptake was ameliorated 4 weeks later, accompanied by an improvement (from 15.1 +/- 7.1 to 23.4 +/- 7.2%, p less than 0.01) in the regional ejection fraction. It is concluded that the degree of asynergy was closely related to the extent of metabolic deterioration in myocardial infarction.

Acute Disease↗
PubMed1998

Glucose metabolism in vivo in crossbred Holstein cattle feeding on different types of roughage during late pregnancy and early lactation.

An experiment was carried out to study the glucose kinetics of crossbred Holstein cattle feeding on either hay or 5% urea treated rice straw during late pregnancy (21 days prepartum) and early lactation (30 days postpartum). In all 16 pregnant heifers (23-25 months of age) were selected for the experiments, including eight animals of two breed types, Holstein Friesian x Red Sindhi (50:50 = 50% HF) and Holstein Friesian x Red Sindhi (87.5:12.5 = 87.5% HF). They were divided into four groups of four animals each. Animals from the same breed type in each group were fed with either rice straw treated with 5% urea or pangola hay (Digitaria decumbens) as the source of roughage throughout the experiments. The glucose turnover rate in both types of crossbred Holstein cattle was determined using a continuous infusion of [U-14C] and 3-[3H]glucose during late pregnancy and early lactation. Total glucose entry and utilization rates increased significantly during lactation for all groups. Recycling of [C]glucose was, approximately 20% in both crossbred cattle fed either hay or urea treated rice straw and was unaffected by the stage of late pregnancy or early lactation. Comparing 50 and 87.5% HF animals, arterial plasma glucose concentrations were slightly higher during pregnant periods but significantly higher in lactating periods in 50% HF animals. The ratio of specific radioactivity of arterial blood bicarbonate relative to that of arterial blood [14C]glucose in the lactating period, significantly decreased in 50% HF animals fed either urea treated rice straw or hay. An increase in udder blood flow during early lactation was significantly higher in 87.5% HF animals than in 50% HF animals. The uptake, arteriovenous differences and extraction ratio for glucose across the udder, significantly increased in the lactating period for all crossbred animals. Glucose uptake by the udder of 87.5% HF animals accounted for 65% of the total glucose turnover rate compared to a value of 46% in the lactating 50% HF animals. It can be concluded that both crossbred cattle fed either urea treated rice straw or hay exhibit the same body glucose turnover rate. The 87.5% HF animal has the genetic potential for a high milk yield and has high body and udder glucose metabolisms compared with 50% HF animals.

Animal Feed↗
PubMed1988

Milk production in concurrently pregnant and lactating goats mated out of season.

Five lactating goats which had kidded normally in March were mated during seasonal anoestrus in May, at the time of peak milk production, after ovulation had been induced using gonadotrophin-releasing hormone (Knight et al. 1988). Milk yield was unaffected by the hormone treatment, and decreased at the same rate as that of control (non-pregnant) goats for the first 8 weeks of the pregnancy. Thereafter yield declined more quickly in the test goats and just before parturition (in October) was 57% of the control value. Following parturition in the test animals, yield rose rapidly as the second lactation was established. None became 'dry' at any stage. Yield continued to decline with advancing lactation in the controls, which were mated normally in October or November and dried-off in December. During their second ('extra') lactation in the winter the test animals produced 12% less than in a normal second lactation in summertime; during the year the extra lactation meant that the test animals produced 73% more milk than the controls. In some, a second concurrent pregnancy was established during the extra lactation, with the result that three lactations were obtained in the time normally taken for two. Mammary cell number and proliferation rate were both higher in the pregnant animals than in the controls in week 23 of the first lactation.

Anestrus↗