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PubMed1995

Regional adaptations of rabbit diaphragm muscle fibers to unilateral denervation.

We hypothesized that adaptations of the rabbit diaphragm (Dia) after unilateral denervation (DNV) result from removal of a neural influence rather than from passive stress. Length changes of midcostal and sternal Dia regions were measured before and after DNV by using sonomicrometry. Midcostal fibers passively lengthened after DNV, whereas sternal fibers shortened. In both regions, these length changes were associated with minimal stress, as estimated from passive force-length relationships. Morphological and contractile adaptions of midcostal and sternal Dia regions were examined after 1 and 4 wk of DNV. In both Dia regions, type I fibers progressively hypertrophied, whereas type IIb fibers atrophied. After DNV, changes in isometric contraction were similar in both Dia regions. Twitch contraction and half-relaxation times increased, force-frequency relationships shifted leftward, and maximum tetanic force decreased. We conclude that passive length changes and mechanical stress are not the main determinants of the morphological and contractile adaptations of the Dia after unilateral DNV but that these adaptations result from DNV itself.

Adaptation, Physiological↗
PubMed1996

Hypothyroidism alters diaphragm muscle development.

The impact of hypothyroidism (Hyp) on myosin heavy chain (MHC) isoform expression, maximum specific force (P0), fatigability, and maximum unloaded shortening velocity (V0) was determined in the rat diaphragm muscle (Dia) at 0, 7, 14, 21, and 28 days of age. Hyp was induced by treating pregnant rats with 6-n-propyl-2-thiouracil (0.05% in drinking water) beginning at gestational day 10 and was confirmed by reduced plasma levels of 3,5,3'-triiodothyronine and thyroxine. MHC isoforms were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and analyzed by densitometry. Isometric P0 and fatigue resistance of the Dia were measured in vitro at 26 degrees C, and V0 was determined at 15 degrees C with the slack test. Compared with control muscles, expression of MHC-slow was higher and expression of adult fast MHC isoforms was lower in Hyp Dia at all ages. The neonatal isoform of MHC continued to be expressed in the Hyp Dia until day 28. At each age, P0 and fatigability were reduced and V0 was slower in the Hyp Dia. We conclude that Hyp-induced alterations in MHC isoform expression do not fully predict the changes in Dia contractile properties.

Aging↗
PubMed1996

Interactive effects of denervation and malnutrition on diaphragm structure and function.

The purpose of this study was to examine the interactive effects of unilateral denervation (DN) and prolonged malnutrition (MN) on the structure and function of the diaphragm muscle (Dia). Four groups of rats were studied: control (Con), MN, DN, and DN-MN. MN began 2 wk after DN and lasted 4 wk. In both the DN and DN-MN groups, the relative loss in Dia weight exceeded the relative change in body weight. Compared with the Con group, Dia specific force was reduced by approximately 40% in both the DN and DN-MN groups but was unaffected in the MN group. Dia fatigue resistance improved in all experimental groups but to a greater extent in the DN and DN-MN groups. In both the DN and DN-MN groups, approximately 50% of Dia fibers were classified as type IIc, whereas fiber type proportions did not change in the MN group. In the DN group, only type IIb/x fibers atrophied, whereas all fiber types atrophied in the MN and DN-MN groups. We conclude that in the DN-MN group the reduction in specific force combined with the reduction in total cross-sectional area of the muscle significantly curtails Dia force-generating capacity.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Anabolic influences of insulin-like growth factor I and/or growth hormone on the diaphragm of young rats.

It is controversial whether insulin-like growth factor I (IGF-I), growth hormone (GH), or their combination might enhance body growth and/or tissue anabolism in the well-fed animal with an intact somatotrophic axis. To assess this further, we studied four groups of adolescent rats: 1) control (Ctr), 2) GH, 3) IGF-I, and 4) GH/IGF-I. IGF-I was given via an osmotic minipump, whereas GH was injected subcutaneously for a period of 72 h. Diaphragm (Dia) contractile and fatigue properties were determined in vitro. Quantitative histochemical and morphometric analyses were performed on Dia fibers. Total serum IGF-I levels were significantly increased in the groups receiving growth factors. Although body weight increased to a greater extent in the animals receiving growth factors, a further synergistic effect was noted in the GH/IGF-I animals compared with either GH or IGF-I groups. Costal Dia mass was greater in the groups receiving growth factors. The Dia of GH/IGF-I animals was more fatigue resistant than the Dia in Ctr. The cross-sectional area of types IIa and IIx fibers were increased to a similar extent in all groups receiving growth factors compared with Ctr. Succinate dehydrogenase activity of type IIa fibers was significantly greater in the GH/IGF-I animals compared with the other groups. We conclude that the short-term provision of growth factors to well-nourished, normally growing adolescent rats can accelerate body growth and promote selective hypertrophy of predominantly type II Dia fibers.

Animals↗
PubMed1999

Force-calcium relationship depends on myosin heavy chain and troponin isoforms in rat diaphragm muscle fibers.

The present study examined Ca(2+) sensitivity of diaphragm muscle (Dia(m)) fibers expressing different myosin heavy chain (MHC) isoforms. We hypothesized that Dia(m) fibers expressing the MHC(slow) isoform have greater Ca(2+) sensitivity than fibers expressing fast MHC isoforms and that this fiber-type difference in Ca(2+) sensitivity reflects the isoform composition of the troponin (Tn) complex (TnC, TnT, and TnI). Studies were performed in single Triton-X-permeabilized Dia(m) fibers. The Ca(2+) concentration at which 50% maximal force was generated (pCa(50)) was determined for each fiber. SDS-PAGE and Western analyses were used to determine the MHC and Tn isoform composition of single fibers. The pCa(50) for Dia(m) fibers expressing MHC(slow) was significantly greater than that of fibers expressing fast MHC isoforms, and this greater Ca(2+) sensitivity was associated with expression of slow isoforms of the Tn complex. However, some Dia(m) fibers expressing MHC(slow) contained the fast TnC isoform. These results suggest that the combination of TnT, TnI, and TnC isoforms may determine Ca(2+) sensitivity in Dia(m) fibers.

Animals↗
PubMed2000

Denervation alters myosin heavy chain expression and contractility of developing rat diaphragm muscle.

We hypothesized that unilateral denervation (DNV) of the rat diaphragm muscle (Dia(m)) in neonates at postnatal day 7 (D-7) alters normal transitions of myosin heavy chain (MHC) isoform expression and thereby affects postnatal changes in maximum specific force (P(o)) and maximum unloaded shortening velocity (V(o)). The relative expression of different MHC isoforms was analyzed electrophoretically. With DNV at D-7, expression of MHC(neo) in the Dia(m) persisted, and emergence of MHC(2X) and MHC(2B) was delayed. By D-21 and D-28, relative expression of MHC(2A) and MHC(2B) was reduced in DNV compared with control (CTL) animals. Expression of MHC(neo) also reappeared in adult Dia(m) by 2-3 wk after DNV, and relative expression of MHC(2B) was reduced. At each age, P(o) was reduced and V(o) was slowed by DNV, compared with CTL. In CTL Dia(m), postnatal changes in P(o) and V(o) were associated with an increase in fast MHC isoform expression. In DNV Dia(m), no such association existed. We conclude that, in the Dia(m), DNV induces alterations in both MHC isoform expression and contractile properties, which are not necessarily causally linked.

Aging↗
PubMed2001

Exogenous testosterone treatment decreases diaphragm neuromuscular transmission failure in male rats.

The effect of chronic exogenous testosterone (T) treatment on neuromuscular transmission in the diaphragm (Dia) muscle of adult male rats was determined. The contribution of neuromuscular transmission failure (NTF) to Dia fatigue was evaluated by superimposing intermittent direct muscle stimulation on repetitive nerve stimulation of isometric contraction in vitro. T treatment significantly reduced the contribution of NTF to Dia fatigue by approximately 20% (P < 0.001). Fiber type-specific effects on NTF were determined by measuring Dia fiber glycogen levels subsequent to repetitive nerve or muscle stimulation. T treatment had no effect on glycogen depletion in Dia type I and IIa fibers regardless of stimulation route. In the control group, type IIx fibers demonstrated significantly less glycogen depletion after nerve stimulation compared with direct muscle stimulation (P < 0.05), suggesting the presence of NTF. In contrast, T treatment increased glycogen depletion of type IIx fibers during nerve stimulation to levels similar to those after direct muscle stimulation. These data indicate that testosterone treatment substantially improves neuromuscular transmission in the Dia.

Animals↗
PubMed1993

Sporadic occurrence of Diego A antigens and antibodies in Berlin.

BACKGROUND: The antigen Dia is common among Mongols (5-12%), but rare in Caucasians (< 1%). OBJECTIVE: The accidental discovery of Diego A (Dia) antibodies in a South American tourist and in an elderly German patient prompted us to investigate the frequency of Dia antigens in the German population. DESIGN: 1,352 German random blood donors, all living in Berlin or in the areas around, were tested for the presence of the Dia antigen on their red blood cells. All donors were Caucasians. RESULTS: Dia was found in 12 individuals (0.89%). CONCLUSIONS: We think that Dia is a low-frequency antigen in the European population. The admixture of Mongol genes following wars or migration is only of low or no importance.

Aged↗
PubMedDate not supplied

Improved assessment of isolated islet tissue volume using digital image analysis.

Accurate and consistent measurement of tissue volume is critical to performing many types of islet research; however, conventional visual determination of isolated islet yields through a microscope is heavily operator dependent. An improved method of islet volume determination using digital image analysis (DIA) was developed to remove operator bias and automate the islet counting process. A series of 140 porcine islet isolations were used to evaluate the DIA method in three separate stages. In Stage 1 (n = 29 isolations), the conventional and DIA methods were correlated with two other independent islet quantitation methods: insulin extraction, and DNA extraction. It was found that volumes determined by DIA correlated more closely with insulin content and DNA content than did conventionally determined volumes. In Stages 2 and 3 (n = 54 and 57 isolations, respectively), it was shown that an increase in the number of fields analyzed by DIA did not significantly improve the quality of the correlations. Inclusion of very small tissue (<50 microm in diameter), which is ignored in the conventional protocol affected yields by less than 10% and did not significantly improve the correlation with insulin or DNA content. Quantitation of isolated islet tissue volume using DIA has been shown to be rapid, consistent, and objective. In the laboratory, use of this method as the standard for islet volume measurement will allow more meaningful comparison of experimental results between centers. In the clinic, its use will allow more accurate dosing of transplanted tissue.

Animals↗
PubMed1987

Control of laryngeal muscle activity in preterm infants.

Control of upper airway muscles, such as those in the larynx, appears important for optimizing airflow patterns during normal respiration. Electromyograms (EMGs) of the laryngeal (LAR) area and diaphragm (DIA) were recorded with esophageal and skin electrodes, respectively, in 12 unsedated sleeping preterm infants during changes in chemical and mechanical feedback. Onset of phasic inspiratory LAR EMG preceded both DIA EMG and inspiratory airflow by 70 +/- 60 and 180 +/- 80 ms, respectively. Inhalation of 4% CO2 increased both peak LAR and DIA EMGs but did not alter their temporal relationships. End expiratory occlusion prolonged both LAR (600 +/- 120 to 930 +/- 290 ms, p less than 0.05) and DIA EMGs (690 +/- 180 to 940 +/- 270 ms, p less than 0.005) as well as mechanical inspiratory time. Early braking of expiratory flow was accompanied by persistence of DIA EMG into the expiratory phase, while termination of mid- to late expiratory braking was associated with onset of the LAR EMG of the subsequent inspiration. We conclude that respiratory activity of the LAR EMG is altered by both chemical and mechanoreceptor stimulation. Furthermore, simultaneous recording of LAR and DIA EMGs suggests that upper airway and chest wall muscles have different effects on expiratory flow patterns in human infants.

Administration, Inhalation↗
PubMed2005

Effect of corn root exudates on the degradation of atrazine and its chlorinated metabolites in soils.

DIMBOA (3,4-dihydro-2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one), a major benzoxazinone of Poaceae plants, was isolated and purified from corn seedlings. The effect of isolated and purified DIMBOA on the degradation of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], and its toxic breakdown products, desethylatrazine [2-chloro-4-amino-6-(isopropylamino)-s-triazine; DEA] and desisopropylatrazine [2-chloro-4-(ethylamino)-6-amino-s-triazine; DIA], was studied in the absence of plants using batch experiments, while the effect of corn root exudates on these compounds was determined in hydroponic experiments. Degradation experiments were performed in the presence and absence of 50 microM, 1 mM, or 5 mM DIMBOA resulting in ratios of DIMBOA to pesticide of 1:1, 20:1, and 100:1. We observed a 100% degradation of atrazine to hydroxyatrazine within 48 h at a ratio of DIMBOA to atrazine of 100:1. DIMBOA had the largest effect on atrazine, while it was about three times less effective on DEA and DIA. Corn (Zea mays L. cv. LG 2185) was exposed to 10 mg L(-1) of either atrazine, DEA, or DIA for 11 d in a growth chamber experiment. Up to 4.3 micromol L(-1) d(-1) of hydroxyatrazine were formed in the nutrient solutions by plants exposed to atrazine, while the formation of hydroxylated metabolites from plants exposed to DEA and DIA was smaller and also delayed. The formation of hydroxylated metabolites increased in the solution with plant age in all atrazine, DEA, and DIA treatments. HMBOA (3,4-dihydro-2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3-one), the lactam precursor of DIMBOA, and a tentatively identified derivative of MBOA (2,3-dihydro-6-methoxy-benzoxazol-2-one) were detected in the corn root exudates. Mass balance calculations revealed that up to 30% of the disappearance of atrazine and DEA, and up to 10% of DIA removal from the solution medium in our study could be explained by the formation of hydroxylated metabolites in the solution itself. Our results show that higher plants such as corn have the potential to promote the hydrolysis of triazine residues in soils by exudation of benzoxazinones.

Atrazine↗
PubMed1999

Comparison of the dot-immunobinding assay with the serum agglutination test, the rose bengal plate test and the milk ring test for the detection of Brucella antibodies in bovine sera and milk.

In this study, Brucella antibodies in bovine sera and milk were detected using the dot-immunobinding assay (DIA), the serum agglutination test (SAT), the Rose Bengal plate test (RBPT) and the milk ring test (MRT). For this purpose, a total of 116 paired blood and milk samples collected at the same time from 56 aborted and from 60 healthy dairy cows was examined. In DIA, a nitrocellulose membrane (NCM) was used as the solid phase. Antigen adsorbed on the NCM was extracted from Brucella abortus S99 by heat treatment. The results obtained by DIA were compared with those of SAT, RBPT and MRT. Of the 116 paired blood and milk samples, 24 were positive and 72 were negative by all tests used. Serum samples of six aborted cows were positive by DIA, SAT and RBPT but the milk samples were negative by DIA and MRT. Serum and milk samples of four aborted cows gave positive reaction only by DIA tests. The remaining six aborted cows were negative only by MRT and two of them were negative by both RBPT and MRT. Four sera of healthy cows were found to be positive only by SAT.

Abortion, Veterinary↗
PubMed2005

Analysis of polyomavirus-infected renal transplant recipients' urine specimens: correlation of routine urine cytology, fluorescence in situ hybridization, and digital image analysis.

Urinary polyomavirus subtype BK (BKV)-infected urothelial and renal tubular cells, "decoy cells," have been shown to be aneuploid with digital image analysis (DIA). We wanted to determine whether decoy cells cause false-positive fluorescence in situ hybridization (FISH) results in BKV-infected urine samples. Urine samples from 38 renal transplant recipients were split 3 ways and evaluated for number of decoy cells per 10 high-power fields by routine cytology, total nuclear DNA content by DIA, and chromosomal abnormalities by FISH. For DIA, Feulgen-stained cells were quantified with a CAS 200 image analyzer (Bacus Laboratories, Lombard, IL), and for FISH, the UroVysion probe set (Vysis, Downers Grove, IL) consisting of chromosome enumeration probes 3, 7, 17, and locus-specific identifier probe 9p21 (p16 gene) was used. Of the 38 specimens, 32 (84.2%) had evidence of BKV infection by routine cytology. DIA and FISH results were aneuploid/aneusomic in 30 (93.8%) and 4 (12.5%) cases, respectively. All aneusomic FISH specimens occurred in men older than 52 years of age and who also had 4 of the 6 highest PCR-BKV titers. To date, no patient has clinical evidence of malignancy. The 6 specimens without decoy cells were DNA diploid/disomic by DIA and FISH. Abnormal FISH results of urinary decoy cells occur much less frequently than aneuploidy by DIA in renal transplant recipients and might merit close follow-up in some transplant recipients.

Adult↗
PubMed1997

[The potentials of echocardiography in the diagnosis of interatrial communications and in the determination of surgical treatment indices].

The authors have examined 550 patients (210 men and 340 women) with the suspected diagnosis of interatrial communication. The age of the patients was from 4 to 53 years (80% of the patients were 10-20 years of age). An original method of prolonged infusion contrast echocardiography and catheterization of the heart were used in 186 patients. Respiration tests were performed in 88 of them. A great defect of the interatrial septum (DIAS) was diagnosed in 31 patients, 15 patients had small DIAS, 40 patients had potent foramen ovale, 464 patients had functional noise. The prolonged infusion contrast echocardiography allowed the right-left shunt to be detected in all the patients with great DIAS, in 86.7% of the patients with small DIAS and in 87.5% of the patients having potent foramen ovale (false positive result was noted only in 2% of the patients with functional noise). The respiration test in patients with functional noise was (21.4 +/- 4)%, with foramen ovale (20 +/- 8)%, with small DIAS (17 +/- 6)% and with great DIAS (8.3 +/- 3)%. The prolonged infusion contrast echocardiography and the respiration test are though by the authors to be indicated to all patients with the suspected diagnosis of the interatrial communication. They allow making the exact diagnosis, estimating the degree of hemodynamic disturbances and determining indications to surgical treatment.

Adolescent↗
PubMedDate not supplied

DOT-dye-immunoassay for the diagnosis of schistosomiasis mansoni.

A new serological assay dot-dye-immunoassay (dot-DIA) was evaluated for the diagnosis of schistosomiasis mansoni. This method consist of four steps: (a) biding of antigens to a nitrocellulose membrane (NC); (b) blocking of free sites of the NC; (c) incubation in specific primary antibody; (d) detection of primary antibody reactivity by color development using second antibody coupled to textile dyes. Sera from 82 individuals, 61 with Schistosoma mansoni eggs in the stool and 21 stool negative were tested by ELISA, dot-ELISA, and dot-DIA. A high level of agreement between the methods tested was observed for all sera tested: ELISA x dot-ELISA: 95.1%, ELISA x dot-DIA: 92.7% and dot-ELISA x dot-DIA: 97.6%. In this study, dot-DIA proved to be a feasible, sensitive, rapid and practical test for the diagnosis of schistosomiasis.

Animals↗
PubMed1995

Induction of diaphorase-1 by dicoumarol in Drosophila virilis larvae.

Drosophila diaphorase-1 (DIA-1) is an enzyme similar to mammalian DT-diaphorase and is inhibited in vitro by dicoumarol. However, a ten-fold increase in DIA-1 activity was observed when third instar Drosophila virilis larvae were fed on a diet containing 0.1 M dicoumarol for 48 h. This induction was shown to be dose dependent and immunoprecipitation experiments with DIA-1 anti-serum demonstrated an increase in the DIA-1 protein level in dicoumarol-treated larvae. The induction of DIA1 by dicoumarol was found to be blocked by actinomycin D, which suggests a transcriptional mechanism of regulation. The opposite effect of dicoumarol on DIA-1 in vitro vs. in vivo suggests that a metabolic conversion takes place after the ingestion of this compound by D. virilis larvae.

Animals↗
PubMed1992

Differential expression of muscular dystrophy in diaphragm versus hindlimb muscles of mdx mice.

Contractile properties of diaphragm (DIA) from mdx and control mice were compared with those of hindlimb muscles [soleus (SOL) and extensor digitorum longus (EDL)] in vitro. Mice ranged in age from 2 weeks to 1.5 years. Muscles were directly stimulated and properties measured were: contraction time, half-relaxation time, active tension per unit area, fatigue index, and maximal velocity of shortening (Vmax). Active tension decreased significantly with age in mdx DIA but not in control DIA. SOL and EDL active tensions were less in mdx than control over the whole age range and did not decrease with age. Vmax was decreased in mdx DIA, but not in mdx SOL or EDL. These results demonstrate that DIA is more affected by muscular dystrophy than hindlimb muscles. Since many Duchenne patients exhibit respiratory distress, this differential expression of dystrophy in diaphragm, as compared to limb muscles, may have important clinical implications.

Animals↗
PubMed1999

Exercise training protects against contraction-induced lipid peroxidation in the diaphragm.

Endurance exercise training promotes a small but significant increase in antioxidant enzyme activity in the costal diaphragm (DIA) of rodents. It is unclear if these training-induced improvements in muscle antioxidant capacity are large enough to reduce oxidative stress during prolonged contractile activity. To test the hypothesis that training-related increases in DIA antioxidant capacity reduces contraction-induced lipid peroxidation, we exercise trained adult female Sprague-Dawley (n = 7) rats on a motor-driven treadmill for 12 weeks at approximately 75% maximal O2 consumption (90 min/day). Control animals (n = 8) remained sedentary during the same 12-week period. After training, DIA strips from animals in both experimental groups were excised and subjected to an in vitro fatigue contractile protocol in which the muscle was stimulated for 60 min at a frequency of 30 Hz, every 2 s, with a train duration of 330 m. Compared to the controls, endurance training resulted in an increase (P < 0.05) in diaphragmatic non-protein thiols and in the activity of the antioxidant enzyme superoxide dismutase. Following the contractile protocol, lipid peroxidation was significantly lower (P < 0.05) in the trained DIA compared to the controls. These data support the hypothesis that endurance exercise training-induced increases in DIA antioxidant capacity protect the muscle against contractile-related oxidative stress.

Animals↗