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PubMed2004

Gender, age and seasonal effects on IgA deficiency: a study of 7293 Caucasians.

BACKGROUND: The frequency of serum IgA deficiency (SIgAD) differs between populations. We examined the prevalence of SIgAD in healthy Caucasians. MATERIALS AND METHODS: Serum immunoglobulin A (SIgA) was measured in 7293 volunteers (2264 women, 5029 men) aged 30 +/- 14.2 years (mean +/- SD; range: 12-66). Serum immunoglobulin A and subnormal SIgA levels were defined by a SIgA level < 0.07 g L(-1), and between 0.07 and 0.7 g L(-1), respectively. Means were compared by analysis of variance (anova) and analysis of covariance (ancova); frequencies by the chi(2) test. RESULTS: Fifteen subjects (0.21%; one woman, 14 men) had SIgAD. Subnormal SIgA levels were found in 155 persons (2.13%): 21 females (0.93% of the females) and 134 males (2.66% of the males; difference: 1.74%; 95% CI: 1.12-2.33%; P < 0.001). Males were more likely to have subnormal SIgA levels or SIgAD (odds ratio 3.09, 95% CI: 1.97-4.85). The prevalence of SIgAD and subnormal SIgA was lowest in winter (chi(2) = 14.8; P = 0.002; 3 d.f.; and chi(2) = 43.2; P < 0.001; 3 d.f., respectively). Serum immunoglobulin A concentrations were significantly higher during winter. Serum immunoglobulin A levels increased with age on average by 0.2 +/- 0.06 g L(-1) per decade of life (P < 0.001). Taking into account the influence of age, SIgA concentration was lower in females as compared with males. CONCLUSION: The prevalence of SIgAD and subnormal SIgA levels is increased in males. There exists a significant influence of gender, age and seasons on SIgA levels.

Adolescent↗
PubMed1985

Students' and teachers' views of a medical college environment in Saudi Arabia.

The instrument used for the assessment of the environment of the College of Medicine at King Saud University, Saudi Arabia consisted of 22 contrasting adjective pairs, separated by a seven-point interval scale along the degree of positive and negative response. The data were collected both from students and teachers. A total of 100 teachers and 150 students were randomly selected. All the respondents were mailed the final instrument with complete sets of instructions and directions. In all, 69 teachers and 97 students returned the completed questionnaire. In order to analyse the data, in addition to analysis of variance, multivariate discriminant analysis was utilized to interpret the data in more than only statistical sense. The implications of these findings for developing intervention strategies to minimize the inadequacies in the academic environment and to influence the development of the students towards the attainment of institutional objectives are discussed.

Attitude of Health Personnel↗
PubMedDate not supplied

Lens morphometry determined by B-mode ultrasonography of the normal and cataractous canine lens.

PURPOSE: To determine axial lens thickness, anterior chamber depth and axial globe length in canine eyes with normal lenses and in eyes with immature, mature, congenital, posterior polar and diabetic cataract. METHODS: B-mode ultrasonography was performed in 50 normal dogs and, as a prephacoemulsification screening procedure, in 100 dogs with cataract. Axial B-mode ultrasonograms were used to determine lens thickness, anterior chamber depth and globe diameter. Statistical comparisons between groups were made by analysis of variance and multivariate analysis, with a significance level of P < 0.05. RESULTS: Axial globe lengths were not statistically significantly different between groups apart from the smaller globes in younger dogs with congenital cataract. Axial lens thickness in diabetics (8.4 +/- 0.9 mm) was statistically significantly different from the lens thickness in normal eyes (6.7 +/- 1.0 mm), eyes with immature cataract (6.4 +/- 0.8 mm) and eyes with mature cataract (7.4 +/- 0.9 mm) although these groups, while varying in thickness, were not statistically significantly different from each other. Anterior chamber depth was statistically significantly reduced in eyes with diabetic cataract (2.9 +/- 0.1 mm) from that in normal eyes (3.8 +/- 0.1 mm), eyes with immature cataract (3.5 +/- 0.1 mm) and eyes with mature cataract (3.2 +/- 0.6 mm) although these groups, while varying in chamber depth, were not statistically significantly different from each other. CONCLUSIONS: Lenses with diabetic cataracts were significantly increased in axial thickness compared to lenses in other eyes, although lenses with mature cataracts showed a trend towards increased axial thickness and immature cataracts demonstrated a trend towards reduced thickness. While previous studies on cataract pathobiology have suggested a reduction in lens thickness in immature cataract through lens protein loss and an increase in thickness in mature cataracts through intumescence, this study is the first to document these changes in the canine lens.

Animals↗
PubMed1998

The effect of dopamine on lung liquid production by in vitro lungs from fetal guinea-pigs.

1. The neuroendocrine system of the lungs has no clear function. However, previous studies of one of its products, somatostatin, have implicated it in lung liquid removal at birth. The present study extends this concept by investigating the effects of dopamine, a major product of this system, on lung liquid reabsorption. 2. The effects of dopamine on fetal lung liquid production and reabsorption were tested on in vitro lungs from fetal guinea-pigs of 60 +/- 2 days of gestation (term = 67 days). Dopamine was placed in the outer bathing saline during the middle hour of 3 h incubations. Fluid movements across the pulmonary epithelium were monitored by a dye dilution method, and changes in rates over 1 h intervals were tested for significance by analysis of variance and regression analysis. 3. Dopamine was able to reduce fluid production or cause reabsorption (based on 42 preparations). Control preparations and those given 10-8 M dopamine showed no significant changes; those given higher concentrations showed significant reductions in production or reabsorption (P < 0.025 to P < 0.0005), according to dose (42.6 +/- 10.8% reduction at 10-7 M; 75.4 +/- 5.9% reduction at 10-6 M; 92.1 +/- 7.0% reduction at 10-5 M and 121.4 +/- 12.8% (reabsorption) at 10-4 M dopamine). The linear log dose-response curve (r = 0.99) showed a theoretical threshold at 1.7 x 10-9 M dopamine. 4. Effects were mediated through specific dopamine receptors (based on 78 preparations). Dopamine at 10-6 M was tested together with each of three dopamine receptor antagonists at 10-5 M. The general dopamine receptor antagonist haloperidol and the more specific D2 receptor blocker domperidone both abolished responses, but the D1 receptor antagonist SCH 23390 was without effect. This suggested that D2 dopamine receptors mediated the responses, and that responses were not due to conversion of dopamine to adrenaline or noradrenaline. 5. There was no evidence that responses involved amiloride-sensitive Na+ transport (based on 54 preparations). Apical amiloride at 10-6, 10-5 or 10-4 M, and the more specific Na+ channel blocker benzamil (10-5 M), had no effect on responses to dopamine, in contrast to their effects on responses to adrenaline in sheep. 6. It is suggested that internal release of dopamine by the neuroendocrine system of the lungs may influence lung liquid reabsorption at birth. This system, which also produces somatostatin, another agent active on lung liquid production, is maximally developed and activated at birth; it is also deficient in hyaline membrane disease.

Amiloride↗
PubMed1982

Impact of coal-coking effluent on sediment microbial communities: a multivariate approach.

The functional response to and recovery from coal-coking waste effluent was evaluated for sediment microbial communities. Twenty estimates of microbial population density, biomass, and activity were measured five times during a 15-month period. Significant effects on microbial communities were observed in response to both wastewater contamination and diversion of the wastewater. Multivariate analysis of variance and discriminant analysis indicated that accurate differentiation between uncontaminated and contaminated sediments required a minimum of nine estimates of community response. Total viable population density, ATP, alkaline phosphatase, naphthalene, and phenanthrene mineralization rates were found to be highly weighted variables in site discrimination. Lipid and glucose mineralization, nitrogen fixation, and sediment protein also contributed significantly to explaining variation among sites. Estimates of anaerobic population densities and rates of methane production contributed little to discrimination among sites in the environment examined. In general, total viable population density, ATP, and alkaline phosphatase activity were significantly depressed in contaminated sediments. However, after removal of this contamination, the previously affected sites demonstrated greater temporal variability but a closer approximation of the mean response at the control site. Naphthalene and phenanthrene mineralization did not follow the general trend and were elevated at the contaminated sites throughout the investigation. Results of the investigation supported the hypothesis that multiple functional measures of microbial community response are required to evaluate the effect of and recovery from environmental contamination. In addition, when long-term effects are evaluated, select physiological traits, i.e., polyaromatic hydrocarbon mineralization, may not reflect population and biomass estimates of community response.

Journal Article↗
PubMed1996

Videokeratography database of normal human corneas.

AIM: To form a database of videokeratography patterns and quantitative indices describing normal human corneas using the absolute scale. METHODS: Both eyes of 195 normal subjects were examined with a TMS-1 videokeratoscope. Videokeratographs were divided into 10 categories based on a classification scheme devised from the absolute scale and analysed with 10 quantitative indices devised to describe phenotypic features of keratoconus videokeratographs. Correlations were sought between videokeratograph patterns and quantitative indices. Additionally, data were analysed for differences in age, sex, and ethnicity. RESULTS: For symmetric videokeratography patterns, analysis in the absolute scale was similar to a previous study done in the normalised scale. In the asymmetric categories, analyses differed markedly. Using the absolute scale and our classification scheme more variation in normal videokeratography patterns could be appreciated. There was good correlation between quantitative indices and videokeratography patterns. Neither videokeratography patterns nor indices differed significantly between sex, ethnic groups, or age using two way analysis of variance. CONCLUSIONS: Pattern analysis of videokeratographs in the absolute scale using, a standard classification scheme, may be more useful in trying to determine whether a cornea is normal or represents subtle early disease than analysis in the normalised scale. Quantitative indices could remove the subjectivity from the decision making process thus facilitating universal reproducibility of videokeratography data interpretation.

Adult↗
PubMed2006

Angiogenesis in nodal B cell lymphomas: a high throughput study.

AIM: To assess the biological significance of vascular endothelial growth factor (VEGF) A, VEGF receptor (Flk-1) and cyclooxygenase 2 (COX2) expression with respect to microvessel density (MVD), proliferative activity (Ki-67), expression of p53 and clinical presentation in a large cohort of nodal B cell lymphomas. METHODS: An immunohistochemical and morphometric study was performed on a validated tissue microarray containing 271 B cell lymphoma specimens, 197 of which included follow-up data. Statistical assessment was done by Pearson's chi(2) test, Spearman's rank correlation coefficient, analysis of variance and survival analysis. RESULTS: 266 (98%) cases were evaluable. Strong VEGF expression was observed in only 20 diffuse large B cell lymphomas (DLBCLs). Flk-1 and COX2 were expressed in 53 and 21 cases, respectively, mainly in DLBCLs, follicular lymphoma (FL) grade 3 and mantle cell lymphomas (MCLs), in a low proportion of cells. MVD decreased in the following order: DLBCLs, FLs, MCLs and small lymphocytic lymphomas/chronic lymphocytic leukaemia (SLL/CLLs). VEGF expression correlated with Ki-67, p53 and COX2 expression in the whole cohort and in DLBCLs. Flk-1 expression correlated with Ki-67 in the cohort and in SLL/CLL and FL grade 1 and 2. COX2 expression correlated with Ki-67 and p53. The analysed angiogenesis parameters did not correlate with clinical parameters or survival. CONCLUSIONS: Angiogenesis plays a differential role in various B cell lymphomas. Aggressive lymphomas express the potential molecular therapeutic targets VEGF and COX2, and have higher MVD. In a few low proliferation-fraction lymphomas, Flk-1 might have a role in proliferative advantage. Therapeutic strategies aimed at angiogenesis should take into account lymphoma heterogeneity.

Aged↗
PubMed2002

Performance of a flat-panel detector in detecting artificial bone lesions: comparison with conventional screen-film and storage-phosphor radiography.

PURPOSE: To compare a large-area direct-readout flat-panel detector system with a conventional screen-film system and a storage-phosphor system in detecting small artificial osseous lesions simulating osteolytic disease and to assess diagnostic performance with decreasing exposure dose. MATERIALS AND METHODS: Artificial lesions (0.5-3.0 mm) were created in 100 of 200 predefined regions in 20 porcine femoral specimens. Specimens were enclosed in containers filled with water to create absorption and scatter radiation conditions comparable with those in a human extremity. Imaging was performed with a flat-panel detector system, a conventional screen-film system, and a storage-phosphor system. Levels of exposure equivalent to speed classes 400, 800, 1600, and 3200 were used. In all images, the presence or absence of a lesion was assessed by three radiologists using a five-point confidence scale. Receiver operating characteristic (ROC) analysis was performed for 4,800 observations (600 for each imaging modality and exposure level) and diagnostic performance estimated with the area under the ROC curve (A(z)). The significance of differences in diagnostic performance was tested with analysis of variance. RESULTS: ROC analysis showed A(z) values of 0.820 (speed class 400), 0.780 (class 800), 0.758 (class 1600), and 0.676 (class 3200) for the flat-panel detector; 0.761 (class 400), 0.725 (class 800), and 0.662 (class 1600) for the storage-phosphor system; and 0.788 (class 400) for the conventional screen-film system. The A(z) value for the flat-panel detector at speed class 400 was significantly higher than that for all other systems (P <.05). A(z) values for the speed class 400 screen-film system and flat-panel detector system at speed class 800 were not significantly different. CONCLUSION: The flat-panel detector has diagnostic performance superior to that of conventional screen-film and storage-phosphor radiography for detecting small artificial osseous lesions at clinical exposure settings. With the flat-panel detector, exposure dose can be reduced by 50% to obtain diagnostic performance comparable with that of a conventional speed class 400 screen-film system.

Animals↗
PubMed2005

Application of the Taguchi analytical method for optimization of effective parameters of the chemical vapor deposition process controlling the production of nanotubes/nanobeads.

Seven variable parameters of the chemical vapor deposition system have been optimized with the help of the Taguchi analytical method for getting a desired product, e.g., carbon nanotubes or carbon nanobeads. It is observed that almost all selected parameters influence the growth of carbon nanotubes. However, among them, the nature of precursor (racemic, R or Technical grade camphor) and the carrier gas (hydrogen, argon and mixture of argon/hydrogen) seem to be more important parameters affecting the growth of carbon nanotubes. Whereas, for the growth of nanobeads, out of seven parameters, only two, i.e., catalyst (powder of iron, cobalt, and nickel) and temperature (1023 K, 1123 K, and 1273 K), are the most influential parameters. Systematic defects or islands on the substrate surface enhance nucleation of novel carbon materials. Quantitative contributions of process parameters as well as optimum factor levels are obtained by performing analysis of variance (ANOVA) and analysis of mean (ANOM), respectively.

Argon↗
PubMed2005

Stigma beliefs of Asian Americans with depression in an internet sample.

OBJECTIVE: To study the beliefs of Asian Americans with depression about stigma associated with depression treatment among friends, employers, and family. METHOD: Participants completed the Center for Epidemiologic Studies-Depression Scale (CES-D) anonymously on the Internet. In this cross-sectional design, those who screened positive for depression were asked questions regarding stigma (n = 68 656). We used analysis of variance (ANOVA) and analysis of covariance (ANCOVA) to compare Asian Americans with whites and also to make comparisons by age and sex. Further, we stratified for Asian Americans and used ANOVA and ANCOVA to compare age and sex. We used linear regression to assess how stigma beliefs were associated with self-reported need for depression treatment. RESULTS: Asian Americans overall had greater stigma beliefs than did whites for all 3 stigma outcomes (P < 0.001), especially those related to family. Although this same pattern existed for subjects aged between 16 and 29 years and between 30 and 45 years (P < 0.001), among those aged under 16 years, this existed for family stigma (P < 0.001) but not for friends or employer stigma. In our stratified analyses among Asian Americans, male participants had greater stigma beliefs than did female participants for friends (P < 0.001) and employer (P < 0.05) but not for family. CONCLUSIONS: The pattern of Asian Americans having greater stigma levels than whites may be changing among younger Asian Americans because of acculturation. Also, among Asian Americans, unlike previous research showing no sex differences for stigma, we show that male participants had greater stigma levels than did female participants. Future directions should include measuring stigma after culture-specific interventions.

Acculturation↗
PubMed1994

Dosage of haloperidol for mania.

BACKGROUND: We compared three doses of a neuroleptic as a treatment for mania. METHOD: Forty-seven newly admitted in-patients with mania were randomised to receive 10, 30, or 80 mg a day of oral haloperidol, under double-blind conditions for up to six weeks. All subjects received prophylactic benztropine. RESULTS: Repeated-measures analysis of variance and survival analysis showed no difference in outcome by the different doses. Excluding drop-outs (38%), most of whom left the study during the first two weeks, 72% of the subjects responded. Side-effects were minimal; there were no differences among the three doses. Non-responders received more adjunctive lorazepam than responders. CONCLUSIONS: The limited data suggest that more than 10 mg a day of haloperidol offers no advantage in mania.

Adult↗
PubMed1991

Diastolic filling characteristics in the stage 12 to 27 chick embryo ventricle.

Cardiac output is affected by the diastolic filling characteristics of the ventricle. We hypothesized that the relative contributions of passive and active filling change as the ventricle develops from a smooth-walled tube to a trabeculated four-chamber heart. In stage 12 to 27 white Leghorn chick embryos, we simultaneously measured ventricular pressure with a servo-null micropressure system and dorsal aortic and atrioventricular velocities with a 20-MHz pulsed-Doppler velocity meter. The analog waveforms were sampled at 500 Hz and converted to digital format via an analog/digital board. We partitioned diastole into passive and active components. The passive phase began with the return of the pressure curve to baseline and extended to the onset of the a-wave. The active phase began with the upstroke of the atrial velocity curve and extended to the upstroke of the ventricular pressure curve at end-diastole. Data are presented as mean +/- SEM (n greater than or equal to 6 at each stage) and analyzed by analysis of variance and regression analysis. At similar cycle lengths ranging from 480 to 600 ms (p greater than 0.05), end-diastolic pressure increased from 0.24 +/- 0.02 mm Hg at stage 12 to 0.55 +/- 0.01 mm Hg at stage 27. Passive and active filling volumes were 92 (0.0038 +/- 0.0005 mm3) and 8% (0.0004 +/- 0.0002 mm3), respectively, at stage 12 and changed to 24 (0.23 +/- 0.08 mm3) and 76% (0.62 +/- 0.08 mm3), respectively, at stage 27. The ratio of passive to active filling volume decreased from 7.89 to 0.35.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Analysis of dynamic atrial dimension and function during early cardiac development in the chick embryo.

Although atrial morphologic changes are well documented, the description of early atrial function is limited. We used videomicroscopic methods to define the function of the contracting atrium in stage 16 to 24 white Leghorn chick embryos. We exposed the embryo in ovo (right side up) and imaged the ventricle, then repositioned the embryo (left side up) and imaged the atrium (n greater than or equal to 8 per stage). We traced the atrial endocardial border and then measured atrial perimeter (mm) and cross-sectional area (mm2). A 20-MHz pulsed Doppler velocity meter was used to measure atrioventricular blood velocity during atrial imaging in an additional six stage 21 embryos. Data were tested by analysis of variance and regression analysis. Mean heart rate change after repositioning was -4 +/- 1%. Atrial maximum and minimum area increased linearly versus embryo stage (y = 0.10x - 1.41, r = 0.89, p less than 0.05 and y = 0.05x - 0.67, r = 0.82, p less than 0.05, respectively). Shortening fraction (percentage of reduction) of atrial perimeter and area decreased from 32.3 +/- 2.0% to 27.5 +/- 1.8% (p less than 0.05) and 56.2 +/- 3.0% to 47.7 +/- 2.0% (p less than 0.05), respectively, from stage 16 to 24. During atrial contraction, the velocity of circumferential wall shortening increased linearly with stage (y = 0.22x - 2.08, r = 0.81, p less than 0.01); however, the velocity of lengthening was similar between stages (p = 0.45). Simultaneous atrial imaging and pulsed Doppler velocity measurement showed that passive atrioventricular flow occurred late in atrial lengthening and active atrioventricular flow occurred during atrial contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Evidence for hypothalamic control of the diurnal rhythms in prolactin and melatonin in the fetal sheep during late gestation.

We have investigated the effect of surgical disconnection of the fetal hypothalamus and pituitary (HPD) on generation of the daily rhythm in fetal plasma melatonin and PRL concentrations under long and short photoperiods. Fetal HPD or a sham operation was carried out at around 110 days gestation. Ewes carrying either HPD fetal sheep (n = 10) or intact fetal sheep (n = 12) were exposed to a long light (LL; 16 h of light and 8 h of darkness) or a short light (SL; 8 h of light and 16 h of darkness) regimen for the remainder of gestation. All ewes were subjected to a 24-h blood-sampling experiment (13 samples collected between 0900-0900 h the following day) between 135-140 days gestation, and fetal and maternal plasma melatonin and PRL concentrations were measured using specific RIAs. The hormonal data were analyzed using multifactorial analysis of variance and cosinor analysis. There was an increase in maternal melatonin concentrations during the dark phase in each lighting regimen in ewes carrying HPD or intact fetal sheep. In the SL regimen, there was also a significant increase in fetal melatonin concentrations during the dark phase in the HPD and intact groups. Under LL conditions, however, fetal melatonin concentrations were only consistently increased during the dark phase in the intact, not the HPD, group. The 24-h mean fetal plasma concentrations of PRL were significantly higher (P < 0.001) in both intact and HPD fetuses in the LL (intact, 111.0 +/- 22.0 pg/ml; HPD, 37.6 +/- 7.3 pg/ml) than in the SL regimen (intact, 37.8 +/- 18.4 pg/ml; HPD, 6.7 +/- 4.3 pg/ml). There was also a significant interaction (P < 0.001) between the effects of fetal surgical treatment and time of day on fetal PRL concentrations. In the intact group, fetal PRL concentrations were significantly higher (P < 0.05) at 1300 and 1700 h than between 0300-0700 h in both lighting conditions. Cosinor analysis also identified a significant rhythm in 8 of the 12 fetal PRL profiles in the intact group. In contrast, in the HPD group, there was no significant effect of time of day on fetal PRL in either the LL or SL regimen, and cosinor analysis only identified a significant rhythm in 2 of the 10 fetal PRL profiles in this group. We have, therefore, demonstrated that in the fetal sheep, HPD resulted in abolition of the diurnal melatonin rhythm under LL conditions and in the loss of the diurnal PRL rhythm under LL and SL conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1981

Piperidine enhances sleep-related and insulin-induced growth hormone secretion: further evidence for a cholinergic secretory mechanism.

Piperidine, a nicotinic cholinergic receptor stimulator, was used in paired design studies of sleep-related and insulin-induced GH and PRL secretion. For the sleep studies, 100 mg piperidine or an equal volume of saline were infused for 30 min starting at sleep onset in eight normal volunteers. The same dose of piperidine was infused for 30 min (beginning 15 min before insulin injection) in an additional eight volunteers undergoing insulin tolerance tests. After piperidine administration, there was a significant (P less than 0.01) enhancement of sleep-related GH secretion, abut no change in PRL. GH concentrations during the first 2 h of sleep were 7.2 +/- 1.2 ng/ml after saline and 15.2 +/-2.9 ng/ml after piperidine (P less than 0.01). No alteration in any measured sleep parameter was noted with the drug. Piperidine did not affect the daytime insulin-induced secretion of either GH or PRL, as assessed by an analysis of variance. However, paired analysis of increments and areas under the response curves indicated a statistically significant effect for GH but not PRL. The maximum GH increment with piperidine was 48.0 +/- 4.3 ng/ml, compared to 36.8 +/- 3.6 ng/ml with saline (P less than 0.01). Piperidine given alone did not influence daytime concentrations of GH. These data are consistent with the view proposed by us, on the bass of methoscopolamine inhibition of nocturnal GH secretion, that cholinergic pathways play a facilitatory role in sleep-related and insulin-induced GH secretion. Thus, cholinergic mechanisms stimulate GH secretion. Nicotinic as well as muscarinic pathways appear to be involved, although the quantitative nicotinic contribution seems to be smaller than the associated with muscarinic sites.

Adolescent↗
PubMed2004

Changes in respiratory mechanics among infants undergoing heart surgery.

UNLABELLED: Children with excessive pulmonary blood flow (PBF) from congenital heart disease have abnormal respiratory mechanics. Exposure to hypothermic cardiopulmonary bypass (CPB) adversely affects lung function. We designed this study of 106 patients to determine the changes in respiratory mechanics in infants younger than 1 yr undergoing heart surgery. Dynamic respiratory compliance (Cdyn) and total respiratory resistance (Rrs) were measured before surgical incision, after sternal closure in the operating room, and after arrival in the intensive care unit. The following data were recorded: age, weight, preoperative pulmonary infiltrates, preoperative mechanical ventilation, evidence of increased PBF before surgery, duration of CPB, duration of aortic cross-clamp, duration of deep hypothermic circulatory arrest, use of steroids, and volume of ultrafiltrate removed. Repeated-measures analysis of variance with covariate analysis was used to determine the effect of each covariate on Cdyn and Rrs at the three time periods. Rrs improved after cardiac surgery correcting increases in PBF, and this was most pronounced in neonates. Among infants with normal or reduced PBF, cardiac surgery with CPB led to a reduction in Cdyn. We consider that the benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of CPB on respiratory mechanics. IMPLICATIONS: The benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of cardiopulmonary bypass on respiratory mechanics in infants.

Aging↗
PubMed2006

Isoflurane preserves spatial working memory in adult mice after moderate hypoxia.

Perioperative hypoxia may contribute to postoperative cognitive impairment. It is unknown, however, whether anesthetics exacerbate or protect against hypoxia-related central nervous system impairment. We sought to determine whether hypoxia alone or in combination with isoflurane disrupts working memory in mice. To this extent, we assigned adult mice to one of four treatments for 1 h: oxygen 21%, oxygen 21% + isoflurane 1.2%, oxygen 8%, or oxygen 8% + isoflurane 1.2%. Mice breathed spontaneously throughout the experiment. Body temperature was maintained at 37 degrees C + 0.5 degrees C. Mice were allowed to recover for 24 h to avoid the confounding influence of residual anesthetics on neurobehavioral performance. Working memory was assessed by use of a Y maze modified for mice. For the training trial, entry to one arm was blocked and mice were permitted to run between the two open arms for 15 min and inspect the objects outside. For the test trial, carried out 1 h later, all arms were open. Time spent in each arm was automatically recorded by a camera and associated software. Mice were tested 1, 4, and 7 days after anesthesia. A different arm was used as the novel arm for each test. Performance was analyzed with repeated-measurements analysis of variance, followed by analysis of simple main effects and by post hoc comparison using Newman-Keuls test when appropriate. P values <0.05 were considered significant. Animals subjected to hypoxia (8% oxygen for 1 h) spent significantly less time in the novel arm 1 day after the insult. The impairment, however, was transient. Hypoxic mice performance improved to the level of the control animals on the fourth post-treatment day. Mice subjected to hypoxia plus isoflurane exhibited no impairment and were comparable to the control group at all time points. Hypoxia transiently impairs performance in a spatial memory task. It appears that isoflurane protects against this deleterious effect of hypoxia.

Animals↗
PubMed2005

Densitometric evaluation of skull and jaw bones after administration of thyroid hormones in rats.

OBJECTIVES: An investigation was performed by use of optical densitometry to observe the effects of different doses of thyroid hormone on bone density of skull and jaw bones and to evaluate the relationship between T3, T4, thyroid stimulating hormone (TSH) serum levels and bone density. METHODS: 40 Sprague-Dawley rats were randomly divided into four groups with 10 rats in each (a control group that received 10 ml kg(-1) i.p. per day normal saline and three levothyroxine groups that received 5, 10, or 20 microg kg(-1) i.p. per day levothyroxine, respectively). Radiographs were taken of their skulls on days 3 and 16. At the end of the experimental period blood was drawn by intracardiac puncture and serum was analysed for thyroid hormones (T3 and T4) and TSH level. After that, optical density measurements were made on the radiographs of four selected points on the skull and jaw with a digital densitometer. Density measurements were analysed using the student's t-test, one way analysis of variance, Spearman correlation analysis and regression analysis. RESULTS: Levothyroxine administration reduced bone density (P < or = 0.05) and increasing the dose of thyroid hormone produced a significant decrease of bone density (P < or = 0.05). The mandible was more susceptible to density changes compared with hard palate, skull and alveolar bone (P < or = 0.05). CONCLUSIONS: Radiographs of the mandible can be utilized to characterize loss of bone density elsewhere. In addition this investigation indicated that optical densitometry is an inexpensive and low risk method for studying bone density.

Absorptiometry, Photon↗