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Barriers to care among American Indians in public health care programs.

OBJECTIVE: We sought to examine the extent to which reported barriers to health care services differ between American Indians (AIs) and non-Hispanic Whites (Whites). METHODS: A statewide stratified random sample of Minnesota health care program enrollees was surveyed. Responses from AI and White adult enrollees (n=1281) and parents of child enrollees (n=572) were analyzed using logistic regression models that account for the complex sample design. Barriers examined include: financial, access, and cultural barriers, confidence/trust in providers, and discrimination. RESULTS: Both AIs and Whites report barriers to health care access. However, a greater proportion of AIs report barriers in most categories. Among adults, AIs are more likely to report racial discrimination, cultural misunderstandings, family/work responsibilities, and transportation difficulties, whereas Whites are more likely to report being unable to see their preferred doctor. A higher proportion of adult enrollees compared with parents of child enrollees report barriers in most categories; however, differences between parents of AIs and White children are more substantial. In addition to racial discrimination and cultural misunderstandings, parents of AI children are more likely than parents of White enrollees to report limited clinic hours, lack of respect for religious beliefs, and mistrust of their child's provider as barriers. CONCLUSIONS: Although individuals have enrolled in health care programs and have access to care, barriers to using these services remain. Significant differences between AIs and Whites involve issues of trust, respect, and discrimination. Providers must address barriers experienced by AIs to improve accessibility, acceptability, and quality of care for AI health care consumers.

Adult↗

Activation of bean (Phaseolus vulgaris) alpha-amylase inhibitor requires proteolytic processing of the proprotein.

Seeds of the common bean (Phaseolus vulgaris) contain a plant defense protein that inhibits the alpha-amylases of mammals and insects. This alpha-amylase inhibitor (alpha AI) is synthesized as a proprotein on the endoplasmic reticulum and is proteolytically processed after arrival in the protein storage vacuoles to polypeptides of relative molecular weight (M(r)) 15,000 to 18,000. We report two types of evidence that proteolytic processing is linked to activation of the inhibitory activity. First, by surveying seed extracts of wild accessions of P. vulgaris and other species in the genus Phaseolus, we found that antibodies to alpha AI recognize large (M(r) 30,000-35,000) polypeptides as well as typical alpha AI processing products (M(r) 15,000-18,000). Alpha AI activity was found in all extracts that had the typical alpha AI processed polypeptides, but was absent from seed extracts that lacked such polypeptides. Second, we made a mutant alpha AI in which asparagine-77 is changed to aspartic acid-77. This mutation slows down the proteolytic processing of pro-alpha AI when the gene is expressed in tobacco. When pro-alpha AI was separated from mature alpha AI by gel filtration, pro-alpha AI was found not to have alpha-amylase inhibitory activity. We interpret these results to mean that formation of the active inhibitor is causally related to proteolytic processing of the proprotein. We suggest that the polypeptide cleavage removes a conformational constraint on the precursor to produce the biochemically active molecule.

Adsorption↗

Pregnancy rates in lactating Holstein-Friesian cows after artificial insemination with sexed sperm.

The effects of artificial insemination (AI) using sexed sperm on pregnancy rates have seldom been studied in lactating dairy cows on commercial dairy farms. We evaluated pregnancy results after AI of 306 lactating dairy cows, of which 157 were inseminated with 2x10(6) frozen/thawed sexed sperm and 149 with 15x10(6) frozen/thawed unsexed sperm. The average pregnancy and calving rates were 21.0% and 20% for the sexed-sperm AIs and 46% and 45% for the unseparated control-sperm AIs respectively (p<0.001). The proportion of female calves derived from sexed-sperm AI was 82% compared with 49% for control AI (p<0.01). The proportion of live and healthy calves in single births was 100% for sexed-sperm AI and 97% for control AI (p>0.05). Our results indicate that AI with low-dose sexed sperm under field conditions in commercial dairy herds without oestrus synchronization results in significantly reduced pregnancy rates compared with normal-dose AI. Improved insemination strategies combined with increased sperm doses are needed before the use of sexed sperm can be of any significant benefit for the dairy and beef industry.

Animals↗

Metabolism of tetradecapeptide, angiotensinogen and angiotensin I and II by isolated perfused rat hindlimbs.

1. We investigated the mechanism of tetradecapeptide-induced vasoconstriction by studying the metabolism of tetradecapeptide (TDP), angiotensinogen, and angiotensin I (AI) and angiotensin II (AII) by isolated perfused rat hindlimbs. 2. Using HPLC and specific RIAs we have quantified six angiotensin peptides: pentapeptide(4-8), hexapeptide(3-8), heptapeptide(2-8), octapeptide(1-8), nonapeptide(2-10) and decapeptide(1-10) in hindlimb effluent. 3. TDP-induced vasoconstriction was associated with generation of predominantly AI and AII, with smaller amounts of the other peptides measured. 4. Captopril prevented vasoconstriction and inhibited AII production by 80%, indicating a dominant role for AI generation in the vascular response to TDP. 5. Evidence that renin is not the enzyme responsible for AI generation from TDP includes: first, the failure of angiotensinogen to cause vasoconstriction or angiotensin peptide generation despite very high amounts of AI and AII generation from TDP; second, the resistance of the TDP-induced vasoconstriction and angiotensin peptide generation to inhibition by pepstatin; and third, the failure of bilateral nephrectomy 24 h before the experiment to influence the vascular and angiotensin peptide response to TDP. 6. AII was cleared with 41% efficiency, with generation of penta-, hexa-, and heptapeptides. 7. AI was cleared with 59% efficiency; this was reduced to 24% by captopril, indicating a conversion of at least 35% of AI to AII by ACE. 8. These studies have identified vascular metabolism of AI and AII to be an efficient process, with both ACE and aminopeptidases playing an important role, and indicate that those peptidases which cleave TDP to generate AI are unlikely to play any role in AI generation in vivo.

Angiotensin I↗

Correlation of temporal lobe glucose metabolism with the Wada memory test.

PURPOSE: The goal of the present study was to examine the relationship of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and the Wada memory test in lateralizing memory dominance and epileptic focus. METHODS: FDG-PET and the Wada test were performed in 18 patients with temporal lobe epilepsy (TLE). The asymmetry indices of FDG-PET (PET-AI) were calculated in mesial, polar, anterolateral, midlateral, and posterolateral regions of the temporal lobe, and those of Wada memory test (Wada-AI) were obtained as well. RESULTS: The Wada-AI was significantly correlated with PET-AI in mesial (r = 0.67, p = 0.003), polar (r = 0.55, p = 0.019), anterolateral (r = 0.55, p = 0.019), and midlateral (r = 0.51, p = 0.031) regions of the temporal lobe. However, after a linear regression analysis, PET-AI of only the mesial temporal region was significantly correlated with Wada-AI (p = 0.008). Wada-AI could correctly lateralize the seizure focus in 90% of the left TLE and 75% of the right TLE patients. The PET-AI of the mesial temporal region showed the highest sensitivity of seizure lateralization (80% of left TLE and 87.5% of right TLE). PET-AI of other temporal regions had lower sensitivities (50-80% of left TLE, 20-75% of right TLE). One or two patients showed false seizure lateralization by PET-AI on each temporal region. CONCLUSIONS: Although FDG-PET hypometabolism is observed at both mesial and lateral regions of the temporal lobe in mesial TLE, mesial temporal region appeared to be a dominant and leading area for lateralizing Wada memory dominance and epileptic focus.

Adolescent↗

Potential for alcohol and prescription drug interactions in older people.

OBJECTIVES: To examine the patterns and prevalence of concomitant alcohol and alcohol-interactive (AI) drug use in older people. DESIGN: Cross-sectional analysis of survey and prescription claims data. SETTING: The Pennsylvania Pharmaceutical Assistance Contract for the Elderly (PA-PACE) program, a state-funded program providing prescription benefits to older people with low to moderate incomes. PARTICIPANTS: A total of 83,321 PA-PACE cardholders (age range 65-106) who were using any prescription medications at the time of survey completion. MEASUREMENTS: All AI drugs were identified using a database of medication warning labels obtained from First DataBank. Prescription drug claims were used to characterize AI drug exposure according to therapeutic class of prescription drug use. A mail survey of PA-PACE cardholders was used to examine alcohol use, as well as sociodemographic and health factors associated with concomitant use of alcohol and AI drugs. RESULTS: Seventy-seven percent of all prescription drug users were exposed to AI medications, with significant variation in exposure and concomitant alcohol use according to therapeutic class. Overall, 19% of AI drug users reported concomitant alcohol use, compared with 26% of non-AI drug users (P<.001). Multinomial logistic regression analyses showed that certain groups of older people, including younger older people, men, and those with higher educational levels, were at greater risk for concomitant exposure to alcohol and AI drugs. CONCLUSION: Many older people use alcohol in combination with AI prescription drugs. Clinicians should warn every patient who is prescribed an AI drug about alcohol-drug interactions, especially those at high risk for concomitant exposure.

Aged↗

Effect of aluminum concentration on dental caries formation in the rat.

OBJECTIVE: Topically applied aluminum (AI) reduced fissure caries in rats with indigenous microflora, but neither therapeutic activity nor concentration effects have been studied in animals infected with caries-inducing bacteria. This study investigated the effects of solutions containing various AI concentrations on formation of smooth surface and sulcal caries in cariogenically challenged rats infected with Streptococcus sobrinus. METHODS: Weanling rats, inoculated with S. sobrinus, were randomly assigned to six groups which were topically treated twice daily with water (treatment control), a NaF solution of 100 parts/10(6) F (positive control), or AIK(SO4)2 solutions containing 100, 1000, 2000, or 4000 parts/10(6) AI. Rats were fed a high-sucrose diet and distilled water ad libitum for 10 weeks, then the molars were scored for enamel and dentin caries. RESULTS: Relative to the water control, NaF and all AI solutions significantly reduced prevalence of both smooth-surface and fissure caries. Protection by AI solutions was greater on smooth surfaces than sulcal areas. AI treatments reduced smooth surface scores by 49-71% and sulcal scores by 27-53%. For all comparisons the protective effect of the 100 parts/10(6) AI solution was less than solutions containing 1000 parts/10(6) AI or more. NaF and all AI solutions also significantly reduced the extent of lesions penetration into dentin. CONCLUSIONS: Topically applied AI reduced the formation and progression of both smooth surface and sulcal caries and showed evidence of a dose response in a rat model infected with S. sobrinus.

Administration, Topical↗

Distribution of antibodies to streptococcal esterases in patients with scarlet fever.

Repetitive counterelectrophoresis (RCE), which has been described (Hayano and Tanaka, 1977), was used to assay the contents of antibodies to streptococcal esterases (STE) in sera from patients with scarlet fever. The levels of antibodies to STE were expressed semiquantitatively by reading the intensity of the colored spot developed by RCE with a densitometer. The present study deals with the determination of anti-STE in sera drawn at intervals from 54 patients diagnosed as suffering from scarlet fever. The STE used in this study were prepared from the streptococcal strains as follows. STE-AI was prepared from SS379 (group A, type 40), STE-AII from strain 69882 (group A, type 49), STE-B from strain H36B (group B, lb), and STE-C from strain Austin (group C). Of the 54 cases studied, 32 (59.3%) showed anti-STE-AI, 24 (44.4%) showed anti-STE-AII, 5 (9.3%) showed anti-STE-B, and 23 (42.6%) showed anti-STE-C. Comparison of the titer of anti-streptolysin O (ASLO) with the type of specific reaction of anti-STE-AI and -AII, determined in the same specimen, showed a marked correlation. Of 20 cases giving ASLO titers of 12 or less, 18 showed no sign of anti-STE-AI and -AII and two showed signs of anti-STE-AI. Of 34 cases giving ASLO titers of more than 12, 33 showed signs of anti-STE-AI and/or -AII, 22 showed signs of anti-STE-AI and -AII, 7 showed signs of anti-STE-AI, and 4 showed signs of anti-STE-AII. Of all the cases, 26 showed coincident rises in titers of ASLO and levels of anti-STE-AI and/or -AII during the course of the disease. One case showed the presence of only anti-STE-B. All of the 23 cases that showed the presence of anti-STE-C showed signs of anti-STE-AI. Some of these cases showed a marked increase in levels of anti-STE-C during the course of the disease.

Antibodies, Bacterial↗

Autoinducer 2 controls biofilm formation in Escherichia coli through a novel motility quorum-sensing regulator (MqsR, B3022).

The cross-species bacterial communication signal autoinducer 2 (AI-2), produced by the purified enzymes Pfs (nucleosidase) and LuxS (terminal synthase) from S-adenosylhomocysteine, directly increased Escherichia coli biofilm mass 30-fold. Continuous-flow cells coupled with confocal microscopy corroborated these results by showing the addition of AI-2 significantly increased both biofilm mass and thickness and reduced the interstitial space between microcolonies. As expected, the addition of AI-2 to cells which lack the ability to transport AI-2 (lsr null mutant) failed to stimulate biofilm formation. Since the addition of AI-2 increased cell motility through enhanced transcription of five motility genes, we propose that AI-2 stimulates biofilm formation and alters its architecture by stimulating flagellar motion and motility. It was also found that the uncharacterized protein B3022 regulates this AI-2-mediated motility and biofilm phenotype through the two-component motility regulatory system QseBC. Deletion of b3022 abolished motility, which was restored by expressing b3022 in trans. Deletion of b3022 also decreased biofilm formation significantly, relative to the wild-type strain in three media (46 to 74%) in 96-well plates, as well as decreased biomass (8-fold) and substratum coverage (19-fold) in continuous-flow cells with minimal medium (growth rate not altered and biofilm restored by expressing b3022 in trans). Deleting b3022 changed the wild-type biofilm architecture from a thick (54-mum) complex structure to one that contained only a few microcolonies. B3022 positively regulates expression of qseBC, flhD, fliA, and motA, since deleting b3022 decreased their transcription by 61-, 25-, 2.4-, and 18-fold, respectively. Transcriptome analysis also revealed that B3022 induces crl (26-fold) and flhCD (8- to 27-fold). Adding AI-2 (6.4 muM) increased biofilm formation of wild-type K-12 MG1655 but not that of the isogenic b3022, qseBC, fliA, and motA mutants. Adding AI-2 also increased motA transcription for the wild-type strain but did not stimulate motA transcription for the b3022 and qseB mutants. Together, these results indicate AI-2 induces biofilm formation in E. coli through B3022, which then regulates QseBC and motility; hence, b3022 has been renamed the motility quorum-sensing regulator gene (the mqsR gene).

Biofilms↗

Energy production, O2 consumption, and blood flow reserve in experimental aortic valve disease.

Left ventricular energy production and its relation to myocardial O2 consumption and blood flow reserve were studied in 11 dogs with surgically produced valvular aortic stenosis (AS, 6 of 11) or combined stenosis and insufficiency (AS + AI, 5 of 11), and 7 dogs undergoing sham operation (S). Two months after operation the combined AS + AI group had the highest left ventricular mass (S, 4.85 +/- 0.53; AS, 6.38 +/- 0.90; AS + AI, 7.23 +/- 0.39 g/kg), left ventricular end-diastolic pressure (S, 2.1 +/- 1.6; AS, 6.3 +/- 1.7; AS + AI, 8.6 +/- 3.1 mmHg), left ventricular end-diastolic volume (S, 61.1 +/- 8.5; AS, 73.0 +/- 7.8; AS + AI, 95.8 +/- 20.9 ml), and stroke work. At rest, total left ventricular myocardial blood flow was increased in AS and AS + AI compared with sham (S, 89 +/- 8; AS, 135 +/- 19; AS + AI, 164 +/- 9 ml/min, P less than 0.05); and coronary resistance was lower in both AS and AS + AI groups. Peak-to-resting flow ratio determined by adenosine vasodilation was reduced in AS and AS + AI despite normal resting function (peak-to-resting flow ratio: S, 6.78 +/- 2.24; AS, 3.19 +/- 0.58, AS + AI, 3.99 +/- 0.84, P less than 0.02). Peak-to-resting flow ratio was inversely proportional to left ventricular mass. In turn the degree of hypertrophy correlated with the total power requirement of the left ventricle, regardless of the type of overload lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Left ventricular myocardial structure in aortic valve disease before, intermediate, and late after aortic valve replacement.

Left ventricular biplane cineangiography, micromanometry, and endomyocardial biopsies were performed in 27 patients with aortic stenosis (AS) and in 17 patients with aortic insufficiency (AI). Twenty-three patients with AS and 15 with AI were restudied at an intermediate time (18 months after successful valve replacement), and nine patients with AS and six with AI were restudied late (70 and 62 months after surgery). Biopsy samples were evaluated for muscle fiber diameter, percent interstitial fibrosis, and volume fraction of myofibrils. In control biopsy samples obtained from five donor hearts at transplantation, these morphometric variables averaged 21.2 microns, 7.0%, and 57.2%, respectively. After surgery, mass determined by cineangiography decreased from 186 to 115 and 94 g/m2 in patients with AS and from 201 to 131 and 93 g/m2 in patients with AI. At the three studies, muscle fiber diameter was 30.9, 28.0, and 28.7 microns in patients with AS and was 31.4, 27.6, and 26.4 microns in patients with AI. Percent interstitial fibrosis was 18.2, 25.8, and 13.7% in patients with AS and was 20.4, 23.7, and 19.2% in patients with AI. Left ventricular fibrous content decreased from 34.2 to 29.8 and to 12.7 g/m2 in patients with AS and from 42.1 to 28.9 and to 18.9 g/m2 in patients with AI. Volume fraction of myofibrils was 57.7, 56.8, and 49.0% in patients with AS and was 56.8, 56.6 and 48.8% in patients with AI. Thus, the decrease of muscle mass determined by cineangiography at the intermediate time after valve replacement is mediated by regression of myocardial cellular hypertrophy in patients with AS and AI and in addition by a decrease of fibrous content in patients with AI. Late after surgery, left ventricular fibrous content also decreases in patients with AS. This late decrease associated with minor changes of end-diastolic volume may be important for improvement of increased diastolic myocardial stiffness. Even 6-7 years after valve replacement, incomplete regression of structural abnormalities of left ventricular hypertrophy still exists compared with the normal myocardium. The residually increased relative interstitial fibrosis and the small late postoperative decrease of volume fraction of myofibrils, associated with a prosthesis-related slight left ventricular pressure increase, are at the origin of a persistent systolic overload at the myofibrillar level.

Adult↗

Mechanism of angiotensin I converting enzyme inhibition by SQ20,881 (less than Glu-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro) in vivo. Further evidence for extrapulmonary conversion.

The mechanism by which the angiotensin I (AI) converting enzyme inhibitor SQ20,881 (less than Glu-Trp-Pro-Arg-Pro-Glu-Ile-Pro-Pro) blocks the pressor response to exogenous AI was studied in vivo in the intact anesthetized dog. When administered as a single dose 250 times that of injected AI (250 nmoles/kg) into either the pulmonary or systemic circulation, SQ20,881 produced inhibition of pulmonary conversion of exogenous AI to AII that lasted for more than 6 hours as judged by the absence of immunoreactive or labeled AII in the pulmonary venous effluent. In contrast, the pressor response to exogenous AI began to reappear within 1 hour of SQ20,881 administration. Six hours following SQ20,881, the pressor response to AI had nearly returned to normal, still in the absence of demonstrable intrapulmonary conversion and without release of detectable amounts of AII into the pulmonary venous effluent. These experiments demonstrated that AI has a pressor effect in the presence of SQ20,881 that is independent of pulmonary conversion. Studies with (Des-Asp) AII and (Des-Asp, Arg) AII showed that the delayed pressor response to AI following SQ20,881 administration could not be accounted for by circulating peptide metabolites of AI or AII. A competitive inhibitor of AII, (D-Asp, Ile) AII completely blocked the returning pressor response, suggesting that extrapulmonary generation of AII was responsible. The data strongly suggest that the systemic vascular bed taken as a whole contains large amounts of AI converting enzyme that is capable of rapid generation of AII without releasing the peptide into circulation. The extrapulmonary enzyme is more resistant to long-lasting blockade by SQ20,881 than pulmonary converting enzyme. The physiological role of extrapulmonary conversion systemic and local circulatory homeotasis remains to be assessed.

Angiotensin I↗

Incidence and management of side effects associated with aromatase inhibitors in the adjuvant treatment of breast cancer in postmenopausal women.

OBJECTIVE: Third-generation aromatase inhibitors (AIs) are effective and generally well-tolerated as adjuvant therapy. These AIs are now being introduced for the adjuvant treatment of postmenopausal patients with estrogen-receptor-positive early-stage breast cancer. However, questions remain about their long-term safety. This paper summarizes the adverse events reported in third-generation AI trials and comments on the appropriate management of these drug-induced adverse events in patients. METHODS: Papers relating to anastrozole, exemestane, and letrozole were identified through Medline searches, and proceedings of recent oncology meetings were also reviewed to capture relevant emerging data. RESULTS: The most commonly reported adverse events associated with adjuvant AI therapy include hot flushes and musculoskeletal complaints/arthralgia. The incidence of endometrial cancer and thromboembolic events is significantly lower with an AI than with tamoxifen. However, there is a small but significant increase in the risk of osteoporosis and fractures with AI therapy. A potential negative effect on the cardiovascular system, specifically on lipid metabolism, has not been conclusively demonstrated. No significant differences in overall quality of life were observed in studies comparing AIs with tamoxifen or placebo. CONCLUSION: AIs alone and sequenced after tamoxifen are an appropriate option for adjuvant endocrine therapy for most postmenopausal patients with hormone-responsive breast cancer. The incidence of some side effects such as endometrial cancer, stroke, or pulmonary embolism associated with tamoxifen is decreased. Monitoring and management of bone loss associated with AI treatment are essential and are being addressed in ongoing trials. Further studies with longer follow-up are required to clarify the effects of AIs on lipid metabolism and cardiovascular health.

Antineoplastic Agents, Hormonal↗

Dilatation of the aortic valve portion in aortitis syndrome. Angiographic evaluation of 70 patients.

The dilatation of the aortic valve portion was evaluated by angiography in 70 patients with aortitis syndrome (Takayasu's arteritis). The diameter at aortic valve commissure was 20 +/- 2.8 min/M2 (NS, vs control) in 46 patients without aortic insufficiency (AI), 23 +/- 2.0 (p less than 0.02, vs without AI) in 11 patients with AI (I or II in grade), 27 +/- 2.0 (p less than 0.01, vs I or II in grade) in 13 patients with AI (III or IV in grade). The diameter was 20 +/- 2.0 in 13 normal control cases and 20 +/- 4.0 in 6 patients with rheumatic AI. The diameters at the levels of aortic valve annulus, sinus of Valsalva and ascending aorta increased also significantly in the patients with AI secondary to aortitis syndrome. The diameter at aortic valve commissure in 24 patients with AI was correlated (r = -0.48, p less than 0.05) to the diastolic blood pressure. Any diameter at the aortic valve portion was not different significantly by the complication of systolic hypertension (greater than or equal to 180 mmHg) in both groups of cases with and without AI. These results indicated that the dilatation of the aortic valve portion was observed in the patient with AI secondary to aortitis syndrome and might be the primary and common cause of AI in all grades, and that the dilatation might not be accelerated by the associated hypertension.

Adult↗

Interhemispheric asymmetry in brain perfusion before and after carotid stenting: a 99mTc-HMPAO SPECT study.

PURPOSE: To assess the effect of unilateral carotid angioplasty and stenting (CAS) on cerebral perfusion asymmetry in patients with severe extracranial carotid stenosis by means of technetium Tc 99m hexamethyl-propyleneamine oxime brain single photon emission computed tomography ((99m)Tc-HMPAO SPECT). METHODS: Twenty-nine consecutive patients (22 men; median age 68 years, range 58-80; 13 symptomatic) undergoing unilateral CAS were included in the study. Brain perfusion was assessed by (99m)Tc-HMPAO brain SPECT prior to the procedure and postoperatively at 8 hours and at 2 to 4 months. The asymmetry index (AI), a measure of the interhemispheric asymmetry in perfusion, was calculated as [(counts in "healthy" hemisphere-counts in hemisphere with carotid stenosis)/counts in "healthy" hemisphere]x100. RESULTS: The preoperative AI demonstrated a wide variation (mean -0.5%+/-8.4%, range -19.5% to 14.1%). There was no significant correlation between the degree of carotid stenosis and preoperative AI. The mean preoperative AI in the asymptomatic patients was lower than in the symptomatic group [-4.0%+/-8.5% (range -19.5% to 8.2%) versus 3.8%+/-6.4% (range -5.2% to 14.1%), p=0.01], suggesting reduced perfusion of the ipsilateral cerebral hemisphere compared to the contralateral side in symptomatic patients. AI variation did not improve after CAS; there was no difference in AI among the 3 SPECT studies (p=0.75). Preoperative AI correlated significantly with late AI (r=0.74, p<0.0001); however, there was no statistically significant correlation between immediate postoperative AI and either preoperative (r=0.24, p=0.217) or late (r=0.24, p=0.249) AI. CONCLUSION: Asymmetry in cerebral perfusion in patients with severe extracranial carotid atherosclerosis does not correlate with the degree of carotid stenosis. Symptomatic patients demonstrate compromised perfusion of the ipsilateral hemisphere compared to asymptomatic patients. As judged by (99m)Tc-HMPAO SPECT scanning, cerebral perfusion patterns do not significantly change after CAS.

Aged↗

Autoinducer 2-like activity in poultry-associated enteric bacteria in response to subtherapeutic antibiotic exposure.

The autoinducer-2 molecule, AI-2, is considered to be a universal signal for regulating a wide variety of physiological processes in bacteria by modulating gene expression. Studies were conducted to observe how Escherichia coli cells would respond to subtherapeutic tetracycline concentrations under continuous culture (chemostat) conditions, to observe AI-2 activity within the probiotic chicken microbial consortium (Preempt CF3; MS Bioscience, Dundee, IL) under in vitro conditions simulating a chicken cecum, and to observe the AI-2 activity in vivo within a chicken cecum as a function of exposure to subtherapeutic levels of chlortetracydine, tylosin, and vancomycin. The AI-2 activity in the E. coli continuous culture showed a 20-fold increase over baseline conditions for up to 24 hours. When the E. coli culture was subsequently exposed to pulses of chlortetracydine additions at subtherapeutic concentrations (2 microg/ml), AI-2 activity increased with increasing levels of tetracycline additions. The probiotic Preempt CF3 culture, however, did not exhibit any AI-2 activity in Viande Levure (VL) medium in the presence or absence of subtherapeutic levels of tetracycline. In vivo studies in the cecum of poultry chicks demonstrate that though AI-2 activity increased initially in the presence of vancomycin, there was no significant increase in AI-2 activity in the presence of tetracydine or tylosin. These results indicate that detectable levels of AI-2 activity are not evident within the probiotic culture (CF3) or within the chicken cecum. Understanding the relationships between AI-2 activity and microbial consortia characteristics could provide dues regarding the vulnerability of poultry chicks to enteric bacterial pathogen colonization.

Animals↗

Effect of addition of a progesterone intravaginal insert to a timed insemination protocol using estradiol cypionate on ovulation rate, pregnancy rate, and late embryonic loss in lactating dairy cows.

The objectives of this study were to determine the effects of incorporating a progesterone intravaginal insert (CIDR) between the day of GnRH and PGF2alpha treatments of a timed AI protocol using estradiol cypionate (ECP) to synchronize ovulation on display of estrus, ovulation rate, pregnancy rate, and late embryonic loss in lactating cows. Holstein cows, 227 from Site 1 and 458 from Site 2, were presynchronized with two injections of PGF2alpha on study d 0 and 14, and subjected to a timed AI protocol (100 mixrog of GnRH on study d 28, 25 mg of PGF2alpha on study d 35, 1 mg of ECP on study d 36, and timed AI on study d 38) with or without a CIDR insert. Blood was collected on study d 14 and 28 for progesterone measurements to determine cyclicity. Ovaries were scanned on d 35, 37, and 42, and pregnancy diagnosed on d 65 and 79, which corresponded to 27 and 41 d after AI. Cows receiving a CIDR had similar rates of detected estrus (77.2 vs. 73.8%), ovulation (85.6 vs. 86.6%), and pregnancy at 27 (35.8 vs. 38.8%) and 41 d (29.3 vs. 32.3%) after AI, and late embryonic loss between 27 and 41 d after AI (18.3 vs. 16.8%) compared with control cows. The CIDR eliminated cows in estrus before the last PGF2alpha injection and decreased (P < 0.001) the proportion of cows bearing a corpus luteum (CL) at the last PGF2alpha injection because of less ovulation in response to the GnRH and greater spontaneous CL regression. Cyclic cows had greater (P = 0.03) pregnancy rates than anovulatory cows at 41 d after AI (33.8 vs. 20.4%) because of decreased (P = 0.06) late embryonic loss (16.0 vs. 30.3%). The ovulatory follicle was larger (P < 0.001) in cows in estrus, and a greater proportion of cows with follicles > or = 15 mm displayed estrus (P < 0.001) and ovulated (P = 0.05) compared with cows with follicles <15 mm. Pregnancy rates were greater (P < 0.001) for cows displaying estrus, which were related to the greater (P < 0.001) ovulation rate and decreased (P = 0.08) late embryonic loss for cows in estrus at AI. Cows that were cyclic and responded to the presynchronization protocol (high progesterone at GnRH and CL at PGF2alpha) had the highest pregnancy rates. Incorporation of a CIDR insert into a presynchronized timed AI protocol using ECP to induce estrus and ovulation did not improve pregnancy rates in lactating dairy cows. Improvements in pregnancy rates in cows treated with ECP to induce ovulation in a timed AI protocol are expected when more cows display estrus, thereby increasing ovulation rate.

Abortion, Veterinary↗

Timing of artificial insemination of dairy cows: fixed time once daily versus morning and afternoon.

Nonreturn rates to professional technician service of 7240 first AI Holstein cows were calculated to evaluate differences between once daily and a.m.-p.m. AI. To determine whether management practices affected nonreturn rates, participating herd owners were surveyed for methods used for detection of estrus. Nonreturn rates for once daily and a.m.-p.m. AI were 64.6 and 65.6% for 60-d, 60.1 and 60.6% for 75-d, and 58.4 and 57.8% for 90-d nonreturn periods. Signs of estrus for AI and interval from detection of estrus to AI were related to nonreturn rates. Nonreturn rate was highest, 63.4%, when cows were in standing estrus. Nonreturn rates were lowest, 36%, when cows were bred after treatment with PGF2 alpha without being detected in estrus or bred strictly on veterinary advice based on palpation. Nonreturn rates were similar for different times of the day when once daily AI was practiced. However, AI in the midmorning may have some advantages. The highest nonreturn rate for a 3-h period was 68.2% for 0800 and 1100 h; the lowest was 54.7% for 1300 to 1600 h. Movement before observation for estrus and an observation period > 15 min improved nonreturn rates for once daily AI. Once daily AI can be used effectively with no difference from the traditional a.m.-p.m. system; results are best when AI is based on standing estrus and performed between 0800 and 1100 h.

Animals↗