An identity-based learning community intervention enhances the lived experience and success of first-generation college students in the biological sciences

Working-class first-generation (FG) college students are underrepresented in higher education and STEM. Using a longitudinal quasi-experiment, we tested the impacts of a living learning community (LLC) in the biological sciences on FG students in their first year of college (Semester 1: N = 243; Semester 2: N = 199), across three cohorts (2018-2019, 2019-2020 and 2020-2021). Participation in the LLC enhanced FG students' belonging, confidence, motivation, grades, knowledge of the social relevance of biology, and reduced STEM anxiety compared to a control group of FG students not in an LLC. LLC participation also increased retention in biological science majors one-year post-intervention compared to the control FG group. Moreover, LLC participation closed the academic gap between FG students in the LLC and honors students from college-educated families in a separate honors LLC. Benefits of the LLC intervention remained stable despite the COVID-19 pandemic, when living together became impossible, producing positive effects across cohorts from pre-pandemic to in-pandemic. Our results suggest that affinity-based learning communities-with or without shared housing-in the transition to college enhance academic thriving, persistence, and reduce social class driven achievement gaps in STEM.

White parents' racial socialization during a guided discussion predicts declines in white children's pro-white biases

Although parent-child conversations about race are recommended to curb White U.S. children's racial biases, little work has tested their influence. We designed a guided racism discussion task for U.S. White parents and their 8-12-year-old White children. We explored whether children's and parents' (a) pro-White implicit biases changed pre to postconversation, (b) racial socialization messages (color conscious, external attributions for prejudiced behavior and colorblind racial ideology [CBRI]) predicted changes in each other's implicit biases, and (c) associations varied by the type of racism (subtle vs. blatant) discussed. Children's and parents' biases significantly declined, pre to postdiscussion. Parents' color conscious messages predicted greater declines and messages reflecting CBRI and external attributions predicted smaller declines in children's bias. These patterns were observed during discussions of subtle, but not blatant bias. Effects of children's messages on parents' bias were mixed. Our findings suggest that color conscious parent-child discussions may effectively reduce implicit pro-White bias in White children. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Psychology Doctoral Program Experiences and Student Well-Being, Mental Health, and Optimism During the COVID-19 Pandemic

In a sample of 916 doctoral students from 144 universities across the United States, we examined psychology graduate students’ experiences in their programs, as well as their mental health, well-being, and optimism during the onset of the COVID-19 pandemic. In a path model, we found that students’ psychological experiences in their programs (i.e., social belonging, threat, and challenge) were associated with better mental health and well-being, which in turn was associated with greater optimism about the future during the COVID-19 pandemic. These findings were also corroborated in students’ open-ended responses regarding how COVID-19 has impacted their lives. Findings varied by racial, gender, and sexual identities, as racial minorities, LGBTQ+ students, and women expressed more negative psychological experiences in their programs. We outline suggestions for graduate programs to support their graduate students, which include facilitating social connection, providing encouragement, and emphasizing students’ well-being over their productivity as the current pandemic persists.

The influence of male faces on stereotype activation among women in STEM: An ERP investigation

Members of stereotyped groups are vigilant to situational cues signaling threats to their social identity. In one psychophysiological experiment, we examined whether mere exposure to a watching male face would increase attentional vigilance among female STEM students due to the activation of math-gender stereotypes. Male and female students performed an alleged math intelligence task while being primed with male faces or control images. Automatic responses to errors were captured with error-related negativity (ERN), a neural index of error vigilance. Women showed larger ERN upon making errors when primed with male faces compared to control images, whereas no such priming effect occurred among men. Moreover, this face priming effect was pronounced only among women highly invested in pursuing STEM careers. These findings suggest that minimalistic social cues may activate negative stereotypes early in informational processing, thereby selectively shunting attention on errors in stereotype-relevant tasks among individuals invested in the performance domain.

Individual differences in sadness coherence: Associations with dispositional affect and age

The current laboratory-based study examined individual differences in sadness coherence (i.e., coherence between objectively coded sad facial expressions and heart rate in response to a sad film clip) and associations with dispositional affect (i.e., positive and negative affect, extraversion, neuroticism) and age in a sample of younger and older adults. Results showed that (a) greater sadness coherence was associated with lower dispositional negative affect (i.e., greater positive to negative affect ratio; lower neuroticism) and (b) older adults had greater sadness coherence than younger adults. Findings remained stable when controlling for covariates. Results were specific to coherence characterized by an inverse association between heart rate and facial expressions of sadness (i.e., did not emerge for absolute changes in heart rate or skin conductance), specific to sad facial expressions (i.e., did not emerge for happy facial expressions), specific to stimulus (i.e., did not emerge for sadness coherence in response to a happy film clip), generalized across overall levels of emotional responding (i.e., sad facial expressions; heart rate reactivity), and remained stable when controlling for expressive suppression. These findings demonstrate that individuals who exhibit greater sadness coherence experience more favorable dispositional affect, consistent with evolutionary-functionalist models of emotion, and that sadness coherence is higher in late life, consistent with developmental accounts of heightened reactivity to loss in late life. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

[Experimental study on DEHP affect the neurodevelopment through interfering with placental thyroid hormones transport]

Objective: The present study was represented by di-(2-ethylhexyl) phthalate (DEHP), to explore the role of thyroid hormones (THs) disruption in the connection of placenta and neurodevelopmental toxicity. Methods: During fetal mice neural tube closed (pregnancy 9.5 days, E9.5d) to begin synthesis of THs (E15.5 d), all pregnant mice were administered with different concentration of DEHP (0、10、50、200 mg/kg) by gavage once a day(10 mice per group). All pregnant mice were conducted with BrdU administration in E14d by subcutaneous injection. Seven pregnant mice from each group were scarified after anesthesia in E15.5 d, serum and amniotic fluid were collected to determinate the levels of THs(T(3), T(4), FT(3) and FT(4)) by the automatic biochemical analyzer, detecting fetal mice placental protein expression of monocarboxylate transporter 8 (MCT8), organic anion transporting polypeptide 1C1 (OATP1C1) and deiodinaseⅡ&Ⅲ (DIO(2), DIO(3)) by Western blot. Each group of the remaining three pregnant mices were killed after anesthesia in E18d, take the male fetal brain, BrdU immunohistochemistry was used to detect the proliferation and migration of fetal brain cortical neurons. Results: There was no abnormalities in diet, water intake, body weight and general activity of pregnant mice in each treatment group, and there were no difference in the general physiolo. Results There was no abnormalities in diet, water intake, body weight and general activity of pregnant mice in each treatment group, and there were no difference in the general physiological development status of body weight, brain weight, brain body ratio between the mice of each group. There was no statistically significant differences in serum T(3), T(4), FT(3), FT(4) and amniotic fluid FT(4) in pregnant mice of each group (P>0.05), Compared with the control group, the FT(3) levels in the amniotic fluid of the DEHP 50 and 200 mg/kg groups were significantly decreased(P<0.05). Compared with the control group, the placental MCT8 and DIO(2) protein levels of male fetal mice in the DEHP 50 and 200 mg/kg group decreased, and the level of OATP1C1 protein in 200 mg/kg group decreased(P<0.05), and there was no statistically significant difference in DIO(3) protein levels among all groups (P>0.05). Compared with the control group, the number of BrdU positive cells in the cerebral cortex of male mice in DEHP 200 mg/kg group decreased, 56.5% was distributed in VZ-SVZ layer, and the percentage of BrdU positive cells in the IZ layer of 50 mg/kg group increased (P<0.05). Conclusion: DEHP 50, 200 mg/kg may affect the proliferation and migration of neural cells in the developing brain, which may be related to its interference with thyroid hormone by placental transport.

[Effects of developmental exposure to DEHP on learning and memory of mice]

Objective: To investigate the effects of developmental exposure to DEHP on learning and memory of mice. Methods: Male littermates of ICR mice randomly assigned to five experimental groups (n=14 for each condition) on PND4 to receive distilled water, vehicle and 10, 50 and 200 mg/ (kg·d) DEHP from PND5 to PND38 by gavage, weighing and recording body weight of mice. Open field task were conducted on PND 26 and Morris water maze task were begun from PND30 to PND 37 to evaluate spontaneous exploration activity and emotion, spatial learning and memory performance of pubertal mice, respectively. On PND39, all animals were killed and hippocampi were isolated on ice, then total proteins of hippocampus were extracted, followed by determining the expression of PSD95 and synapsin I by western blotting. Results: 200 mg/ (kg·d) DEHP significantly reduced the growth of body weight of mice and the time staying in the central area in open field, prolonged the time searching the hidden platform in Morris water maze (P<0.05) . 50 mg/ (kg·d) DEHP didn't change the growth of body weight and the emotion (P>0.05) , but reduced the percent of time and distance in the target quadrant during the probe trial of mice in Morris water maze (P<0.05) . The results of western blotting showed that DEHP significantly reduced the expression of PSD95 in hippocampus of mice with all dose groups (P<0.01) , but only 200 mg/ (kg·d) DEHP reduced the expression of synapsin I (P<0.05) . Conclusion: Developmental exposure to DEHP can damage the development of synapse in hippocampus, adversely impacting spatial memory performance of mice at a dose that are insufficient to significantly influence the general development and result in anxiety.

Ultra-sparse metasurface for high reflection of low-frequency sound based on artificial Mie resonances

Acoustic metamaterials offer great flexibility for manipulating sound waves and promise unprecedented functionality, ranging from transformation acoustics, super-resolution imaging to acoustic cloaking. However, the design of acoustic metamaterials with exciting functionality remains challenging with traditional approaches using classic acoustic elements such as Helmholtz resonators and membranes. Here we demonstrate an ultraslow-fluid-like particle with intense artificial Mie resonances for low-frequency airborne sound. Eigenstate analysis and effective parameter retrieval show two individual negative bands in the single-size unit cell, one of which exhibits a negative bulk modulus supported by the monopolar Mie resonance, whereas the other exhibits a negative mass density induced by the dipolar Mie resonance. The unique single-negative nature is used to develop an ultra-sparse subwavelength metasurface with high reflectance for low-frequency sound. We demonstrate a 0.15λ-thick, 15%-filling ratio metasurface with an insertion loss over 93.4%. The designed Mie resonators provide diverse routes to construct novel acoustic devices with versatile applications.

Band structures of phononic-crystal plates in the form of a sandwich-layered structure

This study investigates the propagation of Lamb waves in phononic-crystal plates in the form of a sandwich-layered structure. The composite plates are composed of periodic layers bilaterally deposited on both sides of the homogeneous core layer. Using the analyses of the band structures and the transmission spectra, it is revealed that the core layer may induce significant modulations to the lower-order Lamb modes. The modulations are ascribed to the reshaped particle displacement fields of the eigenmodes. Prominently, the core layer made of soft material (rubber) combines the identical eigenmodes of the periodic layers into a pair of asymmetric and symmetric modes in which case the periodic layers vibrate independently. However, the core layer made of hard material (tungsten) or medium hardness material (silicon) couples the periodic layers tightly, in which case the composites vibrate as a whole. In addition, it is found that the phononic band gaps are very sensitive to the thickness of the core layer; this could be indispensable to practical applications such as bandgap tuning.

Kinetic Alfvén wave instability driven by a field-aligned current in high-β plasmas

Including the ion-gyroradius effect, a general low-frequency kinetic dispersion equation is presented, which simultaneously takes account of a field-aligned current and temperature anisotropy in plasmas. Based on this dispersion equation, kinetic Alfvén wave (KAW) instability driven by the field-aligned current, which is carried by the field-aligned drift of electrons relative to ions at a drift velocity V(D), is investigated in a high-β plasma, where β is the kinetic-to-magnetic pressure ratio in the plasma. The numerical results show that the KAW instability driven by the field-aligned current has a nonzero growth rate in the parallel wave-number range 0<k(z)<k(z)(u), where the growth rate reaches a maximum at k(z)∼k(z)(u)/2. On the other hand, in the perpendicular wave-number range 0<k(⊥)<k(⊥)(u) the growth rate monotonously decreases with the wave number k(⊥) from a maximum at k(⊥)=0 to zero at k(⊥)=k(⊥)(u). In particular, the upper boundaries of the growing ranges in the wave-number space, k(z)(u) and k(⊥)(u), as well as the growth rate increase with V(D), imply that there are wider growing ranges and larger growth rate for larger drift velocities. Including the temperature anisotropy of plasma particles, the result shows that the instability conditions for these two driven mechanisms are both modified considerably, in which the growing parametric ranges of KAWs widen. The results have potential importance in understanding the physics of space and astrophysical plasma active phenomena since the field-aligned current, also called the Birkeland current, is one of the most active factors in plasma phenomena.

Protective effects of ligustrazine, kakonein and Panax notoginsenosides on multiple organs in rats with severe acute pancreatitis

The aim of this study was to compare the protective effects of three traditional Chinese herbal medicines (ligustrazine, kakonein and Panax notoginsenosides) on multiple organs in a rat model of severe acute pancreatitis (SAP) and to explore the underlying mechanisms. The mortality rates in all three treated groups were significantly lower than the control group (P < 0.05). All three herbal medicines significantly alleviated the pathological changes in the pancreas, liver and kidney in SAP rats, induced pancreatic acinar cell apoptosis and effectively prevented the apoptosis of cells in the liver and kidney; however, no obvious lung protection was observed. Panax notoginsenosides showed better pancreatic protection than ligustrazine and kakonein, while kakonein displayed a better role in improving liver and kidney function. The protective effects of ligustrazine were somewhat more comprehensive.

Temperature effects on the band gaps of Lamb waves in a one-dimensional phononic-crystal plate (L)

This study investigates the temperature-tuned band gaps of Lamb waves in a one-dimensional phononic-crystal plate, which is formed by alternating strips of ferroelectric ceramic Ba(0.7)Sr(0.3)TiO(3) and epoxy. The sensitive and continuous temperature-tunability of Lamb wave band gaps is demonstrated using the analyses of the band structures and the transmission spectra. The width and position of Lamb wave band gaps shift prominently with variation of temperature in the range of 26 °C-50 °C. For example, the width of the second band gap increases from 0.066 to 0.111 MHz as the temperature is increased from 26 °C to 50 °C. The strong shift promises that the structure could be suitable for temperature-tuned multi-frequency Lamb wave filters.

Enhanced Microwave Absorption Properties of Intrinsically Core/shell Structured La(0.6)Sr(0.4)MnO(3) Nanoparticles

The intrinsically core/shell structured La(0.6)Sr(0.4)MnO(3) nanoparticles with amorphous shells and ferromagnetic cores have been prepared. The magnetic, dielectric and microwave absorption properties are investigated in the frequency range from 1 to 12 GHz. An optimal reflection loss of -41.1 dB is reached at 8.2 GHz with a matching thickness of 2.2 mm, the bandwidth with a reflection loss less than -10 dB is obtained in the 5.5-11.3 GHz range for absorber thicknesses of 1.5-2.5 mm. The excellent microwave absorption properties are a consequence of the better electromagnetic matching due to the existence of the protective amorphous shells, the ferromagnetic cores, as well as the particular core/shell microstructure. As a result, the La(0.6)Sr(0.4)MnO(3) nanoparticles with amorphous shells and ferromagnetic cores may become attractive candidates for the new types of electromagnetic wave absorption materials. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11671-009-9374-y) contains supplementary material, which is available to authorized users.

The effects of strontium ranelate in Asian women with postmenopausal osteoporosis

The aim of this study was to assess the efficacy and safety of strontium ranelate in the treatment of postmenopausal women with osteoporosis in Taiwan. In this 12-month multicenter, randomized, double-blind, placebo-controlled study, 125 women with osteoporosis were randomly given either strontium ranelate 2 g daily or placebo. Lumbar spine, femoral neck, and total-hip bone mineral density (BMD) and biochemical markers of bone turnover were measured; adverse events and tolerability were recorded and assessed. Subjects treated with strontium ranelate showed significant increases in BMD of 5.9% at the lumbar spine, 2.6% at the femoral neck, and 2.7% at the total hip, while the placebo group exhibited no significant change at 12 months. Serum level of a formation marker (bone-specific alkaline phosphatase) was also significantly increased at 6 and 12 months. Thus, although the sample size and the treatment duration of this study could not show its effect of reducing osteoprotic fractures, strontium ranelate showed bone protection effects by increasing BMD and concentrations of a bone formation marker. Safety assessment revealed adverse events were mild and not significantly different from placebo.

Study on population genetic structure of Liangshan semi-wool sheep using microsatellite markers

To evaluate the genetic polymorphisms and to search for available molecular markers for Liangshan semi-wool sheep, 15 microsatellite markers of 187 samples were amplified by multiplex PCR. A total of 133 alleles were detected, with the number of alleles ranging from 6 (BM2830) to 15 (McM130), giving a mean No. of 8.87 alleles per locus. The total and mean effective allele No. were 64.29 and 4.29, respectively. The observed heterozygosity and expected heterozygosity were from 0.4486 (McM130) to 0.8877 (BMS1678) and 0.5704 (BMS0887) to 0.8373 (McM130), respectively. Mean observed heterozygosity and mean expected heterozygosity were 0.672 and 0.7536. Polymorphism information content values were from 0.5202 (BMS0887) to 0.8183 (McM130) and mean polymorphism information content of the 15 microsatellite loci was 0.7184. All 15 microsatellite loci were highly polymorphic, which showed that there were rich genetic polymorphisms at these detected microsatellite loci in Liangshan semi-wool sheep. Comparison of allele distributions among loci did not reveal consistent shapes. Distributions were centralized in some cases, whereas in others some kind of skewness was evident. Complex evolution at these loci is an important factor in the irregularity of microsatellite distributions.

Chromosome 15q11-13 duplication syndrome brain reveals epigenetic alterations in gene expression not predicted from copy number

BACKGROUND

Chromosome 15q11-13 contains a cluster of imprinted genes essential for normal mammalian neurodevelopment. Deficiencies in paternal or maternal 15q11-13 alleles result in Prader-Willi or Angelman syndromes, respectively, and maternal duplications lead to a distinct condition that often includes autism. Overexpression of maternally expressed imprinted genes is predicted to cause 15q11-13-associated autism, but a link between gene dosage and expression has not been experimentally determined in brain.

METHODS

Postmortem brain tissue was obtained from a male with 15q11-13 hexasomy and a female with 15q11-13 tetrasomy. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure 10 15q11-13 transcripts in maternal 15q11-13 duplication, Prader-Willi syndrome, and control brain samples. Southern blot, bisulfite sequencing and fluorescence in situ hybridisation were used to investigate epigenetic mechanisms of gene regulation.

RESULTS

Gene expression and DNA methylation correlated with parental gene dosage in the male 15q11-13 duplication sample with severe cognitive impairment and seizures. Strikingly, the female with autism and milder Prader-Willi-like characteristics demonstrated unexpected deficiencies in the paternally expressed transcripts SNRPN, NDN, HBII85, and HBII52 and unchanged levels of maternally expressed UBE3A compared to controls. Paternal expression abnormalities in the female duplication sample were consistent with elevated DNA methylation of the 15q11-13 imprinting control region (ICR). Expression of non-imprinted 15q11-13 GABA receptor subunit genes was significantly reduced specifically in the female 15q11-13 duplication brain without detectable GABRB3 methylation differences.

CONCLUSION

Our findings suggest that genetic copy number changes combined with additional genetic or environmental influences on epigenetic mechanisms impact outcome and clinical heterogeneity of 15q11-13 duplication syndromes.

Model of nonlinear kinetic Alfvén waves with dissipation and acceleration of energetic electrons

The acceleration of energetic electrons has long been one of the most outstanding problems in astrophysics and space physics, and some recent observations from space satellites show that low-frequency electromagnetic fluctuations in the auroral ionosphere and magnetosphere can often be identified as the kinetic Alfvén modes. A model of nonlinear kinetic Alfvén waves is presented here, in which the effect of electron collisional dissipation has been taken into account. The result is a dissipative solitary kinetic Alfvén wave (DSKAW), which can produce a local shocklike structure with a net electric potential drop and which can thereby accelerate efficiently the electrons to the order of the local Alfvén velocity. Since Alfvénic fluctuation is the most common electromagnetic activity in extensive cosmic plasma environments, the present result suggests that the DSKAW could play an important role in the acceleration and energization of cosmic plasmas.

Combination of N-methyl-1-deoxynojirimycin and ischemic preconditioning markedly reduces the size of myocardial infarcts in rabbits

N-methyl-1-deoxynojirimycin (NMDN), an a-glucosidase inhibitor, reduces myocardial infarct size by reducing the glycogenolytic rate through inhibition of the alpha-1,6-glucosidase of glycogen-debranching enzyme in the heart, in addition to possessing an antihyperglycemic action by blocking alpha-1,4-glucosidase in the intestine. Ischemic preconditioning (PC), which markedly reduces the size of the myocardial infarct, is known to reduce the activity of phosphorylase and reduce the glycogenolytic rate. Therefore, it was hypothesized that a combination of pharmacological inhibition of glycogenolysis by an alpha-1,6-glucosidase inhibitor, NMDN, and PC could markedly reduce myocardial infarct size more than NMDN or PC alone. Japanese white rabbits without collateral circulation were subjected to a 30-min coronary occlusion followed by 48-h reperfusion. The infarct sizes as a percentage of area at risk were significantly reduced by pre-ischemic treatment with either 100mg/kg of NMDN or PC of 5 min ischemia and 5 min reperfusion alone (15.9+/-2.0%, n=8, and 10.3+/-1.2%, n=8, respectively) as compared with the control (43.9+/-2.2%, n=8). However, the combination of 100mg/kg of NMDN and PC significantly reduced the infarct size (4.9+/-1.2, n=8) compared with NMDN or PC alone. Another 40 rabbits, also given 100mg of NMDN, PC, NMDN+PC or saline before ischemia (n=10 in each group), were killed for biochemical analysis after 30 min of ischemia. NMDN and PC preserved the glycogen content and attenuated the lactate accumulation, respectively, as compared with the control. However, the combination of NMDN and PC preserved significantly more glycogen and significantly reduced lactate accumulation than either NMDN or PC alone. The combination of NMDN and PC markedly reduced the myocardial infarct size more than either process alone. The marked preservation of glycogen and marked attenuation of lactate accumulation by the combination of NMDN and PC suggest that the mechanism for this effect of NMDN+PC is related to the inhibition of glycogenolysis.

Acute and long-term effects of atrioventricular junction ablation and VVIR pacemaker in symptomatic patients with chronic lone atrial fibrillation and normal ventricular response

INTRODUCTION

The precise role of irregular ventricular response in atrial fibrillation (AF) has not been fully elucidated. This study examined the independent effects of rhythm regularity in patients with chronic AF.

METHODS AND RESULTS

This study included 50 patients who had chronic lone AF and a normal ventricular rate. Among these patients, 21 who underwent AV junction ablation and implantation of a VVIR pacemaker constituted the ablation group; the other 29 patients were the medical group. Acute hemodynamic findings were measured in 21 ablation patients before ablation (during AF, baseline) and 15 minutes after ablation (during right ventricular pacing). Compared with baseline data, ablation and pacing therapy increased cardiac output (4.7 +/- 0.8 vs 5.2 +/- 0.9 L/min; P = 0.05), decreased pulmonary capillary wedge pressure (16 +/- 5 vs 13 +/- 4 mmHg; P = 0.001), and decreased left ventricular end-diastolic pressure (14 +/- 4 vs 11 +/- 3 mmHg; P < 0.05). After 12 months, the ablation group patients showed lower scores in general quality of life (-20%; P < 0.001), overall symptoms (-24%; P < 0.001), overall activity scale (-23%; P = 0.004), and significant increase of left ventricular ejection fraction (44% +/- 6% vs 49% +/- 5%; P = 0.02) by echocardiographic examination.

CONCLUSION

AV junction ablation and pacing in patients with chronic AF and normal ventricular response may confer acute and long-term benefits beyond rate control by eliminating rhythm irregularity.

Occurrence of butyltin compounds in the waters of selected lakes, rivers and coastal environments from China

The presence of butyltin compounds was investigated for the first time in selected lakes, rivers and coastal environments of China. Aqueous samples were pretreated by the technique of headspace solid phase micro-extraction after hydride generation with sodium tetrahydroborate (NaBH4). Quantitative measurement of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) concentrations were accomplished by capillary gas chromatography with flame photometric detector using quartz surface-induced luminescence. Experimental data demonstrated the widespread occurrence of butyltin compounds in the Chinese aquatic environment. In some locations, the concentrations of TBT were higher than the acute and chronic toxicity threshold of sensitive fresh water or marine organisms. Although DBT and MBT (which mainly come from the degradation of TBT), are less toxic, their occurrence can still affect the ecosystem over a long time frame.

Radiofrequency catheter modification of atrioventricular junction in patients with COPD and medically refractory multifocal atrial tachycardia

BACKGROUND

Multifocal atrial tachycardia (MAT) is a difficult clinical problem generally associated with acute cardiorespiratory illness. The purpose of this study was to assess the feasibility and clinical usefulness of atrioventricular (AV) junction modification as a nonpharmacologic therapy for medically refractory MAT.

METHODS AND RESULTS

Thirteen patients with COPD and medically refractory MAT underwent AV junction modification. Complications and outcome of this procedure were monitored. Subjective perceptions of quality of life assessed by a semiquantitative questionnaire and cardiac performance study were obtained before ablation (baseline) and 1 and 6 months after ablation. Radiofrequency energy was applied until the average ventricular rate fell to < 100 beats/min. Ablation procedures controlled the ventricular response in 11 of 13 patients (84%). One patient had unsuccessful modification. Another patient developed delayed complete AV block on the second day after ablation. In these 13 patients, average ventricular rate was reduced from a mean of 145 +/- 11 to 89 +/- 22 beats/min immediately after the ablation (p < 0.01). One patient had recurrent symptomatic MAT at 1 month after ablation; this patient underwent a second procedure without late recurrence. All patients were followed up for at least 6 months (mean, 11 +/- 5 months; range, 6 to 18 months). General quality of life and frequency of significant symptoms improved significantly in patients with successful modification at 1 and 6 months. The left ventricular ejection fraction increased significantly after ablation (44.5 +/- 7.3% at baseline, 49.4 +/- 4. 2% at 1 month, and 50.0 +/- 4.9% at 6 months; all p < 0.05). However, right ventricular ejection fraction remained unchanged (34.7 +/- 6. 2% at baseline, 35.7 +/- 4.4% at 1 month, and 34.3 +/- 4.6% at 6 months; all p > 0.05). The consumption of health-care resources (including frequency of hospital admission and emergency department attendance, antiarrhythmic drug trials) decreased significantly 6 months after AV junction modification. Pulmonary function and theophylline level remained unchanged during follow-up.

CONCLUSIONS

AV junction modification offers an effective therapy for controlling ventricular rate in medically refractory MAT. This procedure improves the quality of life and left ventricular function in selected patients with symptomatic and medically refractory MAT.

Optimization of throughput and desorbent consumption in simulated moving-bed chromatography for paclitaxel purification

In simulated moving-bed (SMB) applications, throughput and desorbent consumption are two key factors that control process cost. For a given adsorbent volume and product purity requirements, throughput and desorbent consumption depend on desorbent composition, column configuration, column length to diameter ratio, and adsorbent particle size. In this study, these design parameters are systematically examined for paclitaxel purification. The results show that if adsorbent particle size, column dimensions and column configuration are fixed, the higher the product purity required, the lower the throughput. If product purity and yield are fixed, the larger the solute migration speed ratio, the higher the throughput, and the lower the desorbent consumption. If total bed volume and product purities are fixed, the longer the separation zones, the higher the throughput, but the higher the desorbent flow-rate. An intermediate configuration gives the minimum desorbent consumption. If there are no limits on pressure drop or zone flow-rate, the larger the column length to diameter ratio, the smaller the adsorbent particle size, the higher the throughput, and the lower the desorbent consumption. If the maximum zone flow-rate is controlled by the pressure drop limit and not by the standing waves requirement, the longer the columns, the lower the zone flow-rates and the lower the throughput. For 150 microns adsorbent particles and a maximum zone flow-rate of 300 ml/min, a design with optimal throughput and desorbent consumption is found for paclitaxel purification.

Effect of correlation between additive and multiplicative noises on the activation from a double well

We study the thermal activation problem of a bistable system driven by correlated additive and multiplicative noises by means of numerical simulation. We find that in the colored noise case the suppression effect of the positive correlation decreases and finally is released as the autocorrelation time tau of the colored noise grows. When tau is large enough, negative correlation becomes more suppressive than the positive correlation. Such phenomena are ascribed to the collaboration between noises as well as the memory effect of the multiplicative colored noise.

Single nucleotide polymorphic discrimination by an electronic dot blot assay on semiconductor microchips

We have developed a rapid assay for single nucleotide polymorphism (SNP) detection that utilizes electronic circuitry on silicon microchips. The method was validated by the accurate discrimination of blinded DNA samples for the complex quadra-allelic SNP of mannose binding protein. The microchip directed the transport, concentration, and attachment of amplified patient DNA to selected electrodes (test sites) creating an array of DNA samples. Through control of the electric field, the microchip enabled accurate genetic identification of these samples using fluorescently labeled DNA reporter probes. The accuracy of this approach was established by internal controls of dual labeled reporters and by using mismatched sequences in addition to the wild-type and variant reporter sequences to validate the SNP-genotype. The ability to customize this assay for multiple genes has advantages over other existing approaches.

Electric field directed nucleic acid hybridization on microchips

Selection and adjustment of proper physical parameters enables rapid DNA transport, site selective concentration, and accelerated hybridization reactions to be carried out on active microelectronic arrays. These physical parameters include DC current, voltage, solution conductivity and buffer species. Generally, at any given current and voltage level, the transport or mobility of DNA is inversely proportional to electrolyte or buffer conductivity. However, only a subset of buffer species produce both rapid transport, site specific concentration and accelerated hybridization. These buffers include zwitterionic and low conductivity species such as: d- and l-histidine; 1- and 3-methylhistidines; carnosine; imidazole; pyridine; and collidine. In contrast, buffers such as glycine, beta-alanine and gamma-amino-butyric acid (GABA) produce rapid transport and site selective concentration but do not facilitate hybridization. Our results suggest that the ability of these buffers (histidine, etc.) to facilitate hybridization appears linked to their ability to provide electric field concentration of DNA; to buffer acidic conditions present at the anode; and in this process acquire a net positive charge which then shields or diminishes repulsion between the DNA strands, thus promoting hybridization.

Trace elements burden in geriatric hemodialysis patients: a prospective multicenter collaborative study

INTRODUCTION

Hemodialysis therapy and the aging process have been reported to interfere with the trace element (TE) status in the body. This multicenter collaborative study on blood levels of TE in geriatric hemodialysis (HD) patients was carried out with an aim to clarify the impact of the aging process and HD therapy on the TE status in such patients.

METHODS

One hundred and fifty-one HD patients (65 male, 86 female), all aged over 60 (68.2+/-3.86 y), and 112 elderly controls (58 male, 54 female) with a mean age of 67.5+/-3.03 were enrolled. All patients underwent standard HD for at least 6 months. The artificial kidneys used were hollow-fiber dialyzers of cellulose membranes. Water used for HD was prepared by reverse osmosis. Blood was collected in the morning prior to dialysis and after fasting. Atomic absorption spectrophotometry was applied to measure blood levels of Pb, Cd and Hg as well as plasma levels of Cu, Zn and Al. Data are presented as mean +/- SEM. Student's t-test and linear regression were applied for statistics.

RESULTS

Our geriatric chronic HD patients showed a marked elevation of blood Al and decreased plasma Zn concentrations. The blood levels of Cu, Cd, Pb and Hg were within normal limits. The blood concentrations of Al, Cu and Pb were significantly higher in HD patients than in the normal elderly controls, whereas Cd and Hg were similar in both groups, and Zn were lower in HD patients. Plasma Zn value decreased as dialysis duration increased, however there was a reversely linear correlation between plasma Zn and age.

CONCLUSIONS

This data reported can be regarded as a starting point and may serve as an insight to further studies on TE imbalances in geriatric and chronic HD populations.

Intrafamilial transmission of hepatitis C virus in hemodialysis patients

The prevalence of hepatitis C virus (HCV) infection in chronic hemodialysis patients ranges from 20 to 50% and these patients may serve as a reservoir of infection for their household contacts. The aim of this study was to investigate the prevalence of anti-HCV in hemodialysis patients and their families, and to evaluate possible routes of infection. One hundred eighty-six family members of 84 hemodialysis patients and 529 healthy adults were enrolled. The family members consisted of 50 spouses, 96 children, 11 parents, 29 siblings, and other relatives living together with the patients. Serum samples were collected for testing anti-HCV. Exposure to risk factors was obtained by a questionnaire and an interview. The results showed that prevalence of anti-HCV in hemodialysis patients was 44%, whereas in family members it was 5.4%, not significantly different from that of age-matched healthy adults (standardized morbidity rate = 1.51, P = 0.390). The anti-HCV rate in family members tended to increase with age, and a spouse of an infected hemodialysis patient had a higher risk of HCV infection than other family members (15% vs. 2.6%, odds ratio 6.6, P = 0.058). Except for the age factor, no difference was found between seropositive and seronegative family members with respect to risk factors such as blood transfusion, surgery, frequent injections, dental procedures, or acupuncture. It was concluded that, although the anti-HCV positivity of hemodialysis patients is high, the risk of HCV infection for their family members is not higher than that of the general population. Among family members, spouses of seropositive hemodialysis patients have the highest risk of HCV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletions of the cyclin-dependent kinase-4 inhibitor gene in multiple human cancers

Cytogenetic abnormalities of chromosome 9p21 are characteristic of malignant melanomas, gliomas, lung cancers and leukaemias. From a panel of 46 human malignant cell lines, we localized by positional cloning the most frequently deleted region on 9p21. Sequence analysis of the isolated fragment reveals two open reading frames identical to the recently described complementary DNA for the inhibitor of cyclin-dependent kinase 4 (CDK4). Polymerase chain reaction and Southern blot analysis confirmed the frequent deletion or rearrangement of the CDK4-inhibitor gene in melanomas, gliomas, lung cancers and leukaemias, and the absence of detectable gene transcripts. One carcinoma had a deletion entirely within the CDK4-inhibitor gene. The CDK4-inhibitor gene from a patient with dysplastic nevus syndrome had a germ-line nonsense mutation. The CDK4 inhibitor is thought to be a physiological suppressor of proliferation. Cells unable to produce the inhibitor may be prone to neoplastic transformation.

Acute myocardial infarction caused by transnasal inhalation of amphetamine

A 42-year-old man developed acute myocardial infarction 20 minutes following transnasal inhalation of amphetamine. To our knowledge, no cases of amphetamine-induced myocardial infarction by transnasal inhalation have ever been reported. Consequently its pharmacological effects on the cardiovascular system are discussed.

Chronic active myocarditis simulating constrictive pericarditis-like findings: report of a case

A 34-year-old female with rhythm disturbance and characteristic hemodynamic features of constrictive pericarditis is presented. A left ventricular wall open needle biopsy revealed mild mononuclear cell infiltration suggestive of myocarditis. The patient died of intractable heart failure seven years later. The autopsy revealed left and right ventricular dilatation, multiple foci of mononuclear cell infiltration, and diffuse replacement fibrosis in 31%, 13% and 14% of the areas of the left ventricular free wall, ventricular septum, and right ventricular wall, respectively, predominantly in the inner layers (68%). The pericardium was intact. These clinically constrictive pericarditis-like findings are considered to be secondary to chronic active myocarditis.

Effects of age and posture on plasma active renin and plasma inactive renin in normal subjects

To investigate the effects of age and posture on plasma active and inactive renin, we measured the plasma active renin concentration (ARC) and inactive renin concentration (IRC) in 81 healthy subjects. The subjects were divided into five groups according to age and body position at the time the blood was taken. Group I included 15 five-day-old newborns in a supine position. Group H included 18 adults, aged from 20 to 50 years, who were in a supine position. Group III included 21 adults, over 50 years old, who were in a supine position. Group IV included 20 adults, aged from 20 to 50 years, who were in an upright position. Group V included 19 adults, over 50 years old, who were in an upright position. Twelve subjects were included in Groups II and IV. Plasma active renin was measured by the amount of angiotensin I general when an exogenous renin substrate was added. Plasma inactive renin was activated by trypsin. The results showed that, in a supine position, both ARC and IRC were significantly higher in newborns (Group I) than in the two adult groups (Groups II and III). The mean of the ARC/TPRC (total plasma renin concentration) ratio was lower in adults over 50 years old (Group III) than in those from 20 to 50 years old (Group II), but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Potential diagnosis of hemodynamic abnormalities in patent ductus arteriosus by cine magnetic resonance imaging

Cine magnetic resonance imaging was performed in 11 patients with communication between systemic and pulmonary circulation. In five patients with uncomplicated patent ductus arteriosus (PDA), ductus arteriosus was delineated by a persistent band of low signal intensity, whereas in two patients who also had severe pulmonary hypertension the signal intensity was varied. Two separate low signal intensities in the main pulmonary artery and the descending aorta were each uniformly recorded in the five patients with uncomplicated PDA, consistent with continuous left-to-right shunt and turbulent flow acceleration, respectively. In one of the patients with severe pulmonary hypertension but not Eisenmenger's syndrome, the areas of low signal intensity from left-to-right shunt and turbulent flow acceleration diminished. In the patient with Eisenmenger's PDA the right-to-left shunt was also characterized by an area of low signal intensity but with a reversal in direction. Cine MR imaging has the potential to be a noninvasive and supplemental method for evaluating PDA.

Intracranial calcification and brachydactyly mimicking Albright's hereditary osteodystrophy in an adult patient with lingual thyroid and prolactinoma-like lesion

Hyperprolactinemia and prolactinoma in patients with long-term primary hypothyroidism have been recognized for decades. We report a case of 57-year-old female patient with lingual thyroid and cretinism who had a high serum prolactin level (greater than 200 ng/ml) and a pituitary tumor with suprasellar and parasellar extension. The tumor regressed to a size undetectable by CT scan after 2 years of thyroid hormone replacement therapy, but complete normalization of the hyperprolactinemia required additional bromocriptine therapy. This patient showed generalized short metacarpal and phalangeal bones, calcification of the basal ganglia and dentate nuclei bilaterally, and subcutaneous calcification at both gluteal regions, while serum calcium, phosphorus and c-PTH levels were all normal. Thus in addition to short stature, brachydactyly, a round face, and obesity, which are related to hypothyroidism, she also presented features uniquely mimicking the Albright's hereditary osteodystrophy seen in patients with pseudohypoparathyroidism and pseudopseudohypoparathyroidism. Since she had no family history of pseudohypoparathyroidism and had a normal level of Gs alpha protein on the membrane of the red blood cells, there is no evidence of pseudopseudohypoparathyroidism. The cause of the ectopic calcification remains unknown.

Clinicopathological study of myocardial infarction with normal or nearly normal extracardiac coronary arteries. Quantitative analysis of contraction band necrosis, coagulation necrosis, hemorrhage, and infarct size

In order to clarify the pathogenesis of acute myocardial infarction (MI) in hearts with normal coronary arteries, infarct size, and the extent of contraction band necrosis (CBN), coagulation necrosis, and hemorrhage were quantitatively examined using an image analyzer in 5 autopsy cases of MI with normal or nearly normal extracardiac coronary arteries. One patient died 40 h after acute MI. A second patient with acute MI due to severe spasm of segment 6, confirmed by cineangiography, died three days later. The third patient had already suffered a subarachnoid hemorrhage, and died 10 h after the onset of acute MI. The fourth patient had aortic stenosis and regurgitation. She developed acute MI due to total occlusion of segment 6, confirmed by cineangiography 4 h after the onset, and died 61 days later. Autopsy revealed old anteroseptal MI with normal coronary arteries and valvular thrombi. The fifth patient had a malignancy, and died one day after the onset of acute MI. Autopsy revealed multiple occlusive thrombi in the small intramural coronary arteries of the left ventricular wall supplied by segment 14, without any stenosis in the feeding vessel. Most infarcts were localized in the territory supplied by 1 or 2 of the 3 epicardial coronary arteries, and coincided with the clinically diagnosed infarct site. The infarct size ranged from 3%-26% of the left ventricular wall, and infarcts were generally localized to the inner third of the wall (67 +/- 20%). Histological examination of the four patients with acute MI revealed diffuse CBN (86 +/- 14% of the infarcted area) and/or hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Anginal attack following a sodium bicarbonate and hydrocortisone injection

A case of a 73-year-old man with variant angina who developed chest pain and shock following an injection of sodium bicarbonate and hydrocortisone is reported. The electrocardiogram (ECG) during the chest pain attack revealed ST elevation in leads II, III and aVF. It returned to a normal pattern 10 min later. Coronary angiography, performed 2 hours after the anginal attack, showed no significant coronary arterial stenosis. One month later, an injection of ergonovine (16 micrograms) into the right and left coronary arteries induced spasms in segments 4 and 13, with ischemic ECG changes. Possible causes of the anginal attack are a coronary arterial spasm induced by the allergic reaction to hydrocortisone and/or serum alkalosis due to the sodium bicarbonate injection triggered by hyperventilation.

Response of large and small coronary arteries of pigs to intracoronary injection of acetylcholine: angiographic and histologic analysis

With coronary arteriography we examined the effect of acetylcholine (ACh) on large and small coronary arteries. ACh (12.5 to 200 micrograms) was injected into the right coronary arteries of 10 pigs during left ventricular pacing. The percentage of narrowing of the epicardial major coronary artery was used as an indicator of the constriction of the large coronary arteries, and the time required for the contrast medium to reach the posterior descending coronary artery from the ostium of the right coronary artery (blood-flow delay) was used as an indicator of the constriction of the same coronary arteries. A small dose of ACh (12.5 to 100 micrograms) induced mild narrowing (14 to 41%) of the epicardial major coronary artery and a marked blood-flow delay of over 7.0 sec (control: less than or equal to 1.8 sec) in all 10 pigs. A large dose of ACh (100 to 200 micrograms) caused over 75% narrowing of the epicardial major coronary artery and a marked blood-flow delay in 4 of the 10 pigs. When the marked blood-flow delay appeared, the perfused right ventricular myocardium became macroscopically anemic (ischemic). The constriction of large and small coronary arteries was not prevented by diphenhydramine (H1 blocker: 100 mg i.v.), but was prevented by pretreatment with atropine (1.0 mg i.v.). The intracoronary injection of histamine (1.5 mg) in 5 pigs constricted the epicardial major coronary artery over 75% in 2 pigs, 50 to 75% in 1 pig, and 25 to 50% in 2 pigs, but there was no evidence of blood-flow delay. Neither methoxamine nor norepinephrine caused any significant coronary artery narrowing. The histology of the large and small coronary arteries was examined quantitatively with an image analyzer. The coronary artery showed no intimal thickening, and the endothelium was intact on light microscopic examination. The % area of the smooth muscle layer (media) to the calculated total vascular area, and the ratio of the calculated medial thickness to the calculated inner radius (h/Ri) were 64 +/- 7% (mean +/- SD) and 0.69 +/- 0.16, respectively, in the small coronary arteries less than 100 microns in external diameter, 47 +/- 9% and 0.39 +/- 0.12 in the small coronary arteries 100 to 2000 microns in external diameter, and 34 +/- 4% and 0.24 +/- 0.03 in the large right coronary arteries over 2000 microns in external diameter; the % area of the media and the h/Ri showed a negative correlation with the size of the coronary arteries.(ABSTRACT TRUNCATED AT 400 WORDS)

High frequency of spontaneous acute myocardial infarction due to small coronary artery disease in dead (NZWxBXSB)F1 male mice

To determine whether or not male (NZWXBXSB)F1 [WXB)F1) mice exhibiting a lupus-like syndrome died of acute myocardial infarction (MI), and whether acute MI is directly related to small coronary artery disease, acute and old MIs were examined histologically in 55 dead (WXB)F1 male mice and 30 age-matched, surviving (WXB)F1 male mice used as a control group. In each heart from the 15 dead mice with MI and the five surviving mice without MI, 300 to 400 5-microns-thick serial sections were made; every fourth section was stained. Acute MI was found in 35 (64%) dead mice and in one (3%) survivors, whereas old MI was found in 50 (91%) dead mice and 17 (57%) survivors: a significant difference between the dead and surviving mice. The MIs were numerous, scattered, and small in most mice. Quantitative analysis revealed that the percentage of acute MI and old MI in the left ventricular (LV) wall was 6% +/- 11% and 3% +/- 3% in the dead group, and 0.4% and 2% +/- 3% in the control group. This indicated that recurrent acute MI is a major factor in the death of the mice. Although all the epicardial major coronary arteries of the (WXB)F1 male mice were intact, significant stenoses were noted in the intramyocardial small arteries. The serial sections in the 15 dead mice with MI revealed 1) segmental occlusive thrombi in the infarct-related small coronary artery in 14 of the 20 foci of acute anemic MIs, two of the 18 foci of acute hemorrhagic MIs, and four of the 58 foci of old MIs; and 2) segmental intimal thickenings in the infarct-related small artery in six of the 20 foci of acute anemic MIs, two of the 18 foci of acute hemorrhagic MIs, and 56 of the 58 foci of old MIs. There was no evidence of small coronary artery disease in the surviving mice without MI. The thrombus would result in thickened intima as MI progresses from the acute to the old stage. Because it was established that acute MI of hemorrhagic type follows reperfusion after transient occlusion of the coronary artery, hemorrhagic acute MI with rare incidence of thrombi in this mouse suggests that thrombolysis occurs after occlusion due to thrombus formation. Thus, the pathogenesis of multiple MIs is occlusive thrombi, recanalization in small coronary arteries or both. Some of the mice had dilated cardiomyopathy (DCM)-like features (marked LV dilatation).(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of propranolol on high energy phosphate and tissue acidosis in regional ischemic myocardium of pigs: assessment with arterial pressure and respiration gated in vivo 31-phosphorus magnetic resonance spectroscopy

In an attempt to define the metabolic abnormalities of the ischemic myocardium, the changes in high energy phosphates, inorganic phosphate and intracellular pH were serially and quantitatively evaluated in ischemic porcine hearts having no collateral circulation, using arterial pressure and respiration gated in vivo 31P magnetic resonance spectroscopy. The protocol was also modified for propranolol pretreatment (0.6 mg/kg intravenously) to define its effect on the metabolism of ischemic myocardium. In the non-treated group, creatine phosphate was rapidly depleted by 10 minutes after ischemia; by 40 minutes, ATP and intracellular pH gradually decreased to 10 +/- 11% of control and to 5.90 +/- 0.26, respectively, and inorganic phosphate rose to 303 +/- 43% of control. In the propranolol treated group, the concentrations of creatine phosphate and ATP were higher, and those of inorganic phosphate and tissue pH were similar compared with controls during 40 minutes of ischemia. This suggests that the beneficial effect of propranolol on the ischemic myocardium is due to the preservation of ATP, an essential energy resource for numerous enzymatic reactions in viable myocardium.

[Correlations between results of selective intracoronary thrombolysis and histologic findings of the infarct-related coronary arteries]

To define the histopathogenesis of successful and unsuccessful recanalization following selective intracoronary thrombolysis, coronary angiography (CAG) in thrombolysis and histologic findings were compared in 13 patients who died within four days (mean 1.5 days) after the procedure. Thirteen infarct-related arteries were evaluated in respect to recanalization; presence of an intraluminal thrombus, and rupture and hemorrhage of atheromatous plaques were histologically evaluated in serial sections. Intraluminal thrombi of the infarct-related coronary artery were found in all of the five cases with unsuccessful recanalization and in none of the eight cases with successful recanalization. Rupture and hemorrhage of atheromatous plaques in infarct-related arteries were observed in all of the five cases with unsuccessful recanalization and in seven of the eight cases with successful recanalization. It was concluded that 1) in recanalized cases, thrombi are considered to be lysed; 2) unsuccessful recanalization does not necessarily indicate the absence of thrombi; and 3) rupture and hemorrhage of atheromatous plaques do not affect recanalization.

Deficient erythrocyte membrane Gs alpha activity and resistance to trophic hormones of multiple endocrine organs in two cases of pseudohypoparathyroidism

Patients with pseudohypoparathyroidism (PHPT) have been shown to have deficient cell membrane stimulatory GTP-binding regulatory protein activity (Gs activity) and other defects, which cause renal resistance to parathyroid hormone (PTH). Those patients also have a higher incidence of deficiency of other endocrine axes. To investigate the mechanisms of this syndrome on 2 patients, we measured erythrocytic ghost Gs activity by ADP-ribosylation method, which showed low and low normal levels for the 2 patients who were from the same family, suggesting type Ia of this syndrome. While basal T3, T4 and TSH were compatible with mild primary hypothyroidism in both patients, a TRH test showed exaggerated TSH responses. The estrogen, progesterone and testosterone levels were low and LH and FSH responses were marginally high, indicating gonadal resistance to gonadotropins. ACTH levels were also elevated and ACTH response to CRH was exaggerated in one patient, suggesting additional primary adrenal insufficiency. This finding indicates that systemic endocrine tests are essential for the management of PHPT patients who may have a deficiency of multiple endocrine axes subclinically.

Cineangiographic and pathological features of the infarct related vessel in successful and unsuccessful thrombolysis

The postmortem histology and the results of cineangiography after selective intracoronary thrombolysis in vessels that were recanalized and in those that were not were compared in 21 patients who died within seven days (mean 2 days) of selective intracoronary thrombolysis. There was a persistent intraluminal thrombus in the infarct related coronary artery in five of six segments in which recanalisation was unsuccessful and in one of 15 segments in which recanalisation was successful. Rupture and haemorrhage of the atheromatous plaque were seen in most of the infarct related segments, both in those in which recanalisation was achieved and in those in which it was not. Irregular narrowing and filling defects on the coronary cineangiograms were associated with rupture and haemorrhage of the atheromatous plaque. These results suggest that failure of coronary thrombolysis to recanalize the infarct related artery does not indicate that the occlusion was not caused by thrombus.

Acceleration of cell necrosis following reperfusion after ischemia in the pig heart without collateral circulation

A study of whether reperfusion accelerates cell death was performed in 35 pig hearts without collateral circulation. In 15 animals, the distal one-third of the left anterior descending coronary artery was occluded for 1 hour followed by 1-, 3-, or 7-hour reperfusion in 5 animals each. As controls, 5 hearts each were examined after 1, 2, 4 and 8 hours of occlusion of the artery without reperfusion. Heart rate and aortic pressure before and during occlusion and reperfusion did not change in any group. The subepicardial and subendocardial regional blood flow decreased to almost zero in all hearts after occlusion (85 +/- 1 to 2 +/- 2) but recovered during reperfusion (65 +/- 15 ml/100 g/min). Specimens were histologically examined by an enzyme method using nitrotetrazolium blue, an immunohistochemical method using myoglobin antibody, by staining with hematoxylin-eosin and Masson's trichrome. In the control hearts, clear demarcation of the infarct area was observed 4 hours after occlusion. However, in the reperfusion group, clear demarcation of the infarct was seen after 1-hour reperfusion, namely, 2 hours after the onset of infarct. Demarcation was seen not only in the tissue with contraction band necrosis, but also in the tissue with coagulation necrosis. Therefore, it is concluded that reperfusion accelerates cell death due to both contraction band necrosis and coagulation necrosis.

Distribution and progression of coronary arterial and aortic lesions in the conventional Watanabe heritable hyperlipidemic rabbit--quantitative analysis

The distribution and progression of coronary arterial and aortic lesions were examined in 40 conventional Watanabe heritable hyperlipidemic (WHHL) rabbits. They were classified according to age into stage I (3-5 months old, 14 rabbits), stage II (6-12 months old; 12 rabbits) and stage III (14-28 months old; 14 rabbits). Fifteen normal Japanese rabbits served as controls. The findings obtained from serial and transverse sections of each of the extramural coronary arteries (ECA) and transverse sections of 4 to 5 equal pieces of whole ventricle for intramural coronary arteries (ICA) were quantified by an image analyzer. Atherosclerosis with positive Sudan III stain was seen in aorta, ECA and ICA over 200 mu in diameter. Atherosclerotic lesions were noted in the aortic arch in stage I rabbits and in the whole aorta in stages II and III rabbits. In ECA, stenosis due to atherosclerosis was noted in 14, 33 and 93% of stages I, II and III rabbits, respectively. Stenosis of over 75% in the orifices of the left and right coronary arteries was noted frequently (71%), while mural thrombi, hemorrhage, intimal rupture and recanalization were seen rarely. Striking features were non-atherosclerotic stenosis with negative Sudan III, seen in the ICA less than 200 mu in diameter of almost all the hearts of stages II and III rabbits. Acute and old myocardial infarction appeared in 5 of the 14 hearts of the stage III rabbits and the infarct-related ECA showed severe stenosis of over 90%. In conclusion, to detect coronary atherosclerosis, serial and transverse sections of ECA are needed. In conventional WHHL rabbits, the incidence of stenosis in ECA is very high, compared with that of the previous reports, and myocardial infarction is due to severe stenosis in ECA. Non-atherosclerotic lesions in ICA occur before the appearance of the atherosclerotic lesions in ECA.

Quantitative analysis of infarct size, contraction band necrosis, and coagulation necrosis in human autopsied hearts with acute myocardial infarction after treatment with selective intracoronary thrombolysis

To assess the importance of contraction band necrosis (CBN) in patients with acute myocardial infarction (AMI) treated with selective intracoronary thrombolysis, CBN, coagulation necrosis, and infarct size (expressed as CBN + coagulation necrosis) were analyzed quantitatively in 16 autopsied hearts. Intracoronary thrombolysis was performed from 2 to 6 hr after the onset of AMI, and the time from the onset of AMI to death was 7 to 168 hr. Cineangiography revealed no evidence of good collateral circulation in any of the patients. The 16 patients were classified into three groups: six patients with successful thrombolysis (100% to 99% stenosis, group I), five patients with unsuccessful thrombolysis (100% to 100%, group II), and five patients with 99% stenosis before thrombolysis (group III). Among the three groups, there were no significant differences in the time from the onset of AMI to thrombolysis, the time from the onset of AMI to death, the cause of death, or the degree of collateral circulation. The percentage of the risk area involved by the infarct in group I (82 +/- 6%) was similar to that in group II (80 +/- 11%). Infarct size was not reduced in group I because collateral circulation was not good and because the degree of recanalization after thrombolysis was 1%. However, the percentage of the infarct area with CBN was significantly higher in group I (20 +/- 9%) then in group II (3 +/- 3%). This finding shows that diffuse CBN occurred after reperfusion in patients with AMI treated with thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Limitation of coronary thrombolysis: experimental study of reperfusion after ischemia

Contraction band necrosis (CBN), coagulation necrosis (CN) and infarct size, expressed as CBN + CN, were quantitatively analyzed in 15 pig hearts without collateral circulation. The left anterior descending coronary artery was ligated for 60 and 120 minutes and then reperfused for eight hours (group 1 and 2, respectively). Five hearts were not reperfused (group 3). There was no change in hemodynamics with either occlusion or reperfusion. Regional myocardial blood flow, measured by the generated hydrogen gas clearance method, decreased to almost zero after occlusion but recovered during reperfusion. Percent infarct area of the perfused area in group 1, 2 and 3 were 80 +/- 9, 96 +/- 2% and 95 +/- 3%, respectively. The percent area of CBN was 68 +/- 11% in group 1, 2 +/- 1% in group 2 and 2 +/- 2% in group 3. We conclude that in pig hearts without collateral circulation, the transmural infarct, two-thirds of which is occupied by CBN, is evident even in reperfusion following one-hour occlusion. Therefore, in patients with acute myocardial infarction, coronary thrombolysis should be performed within one hour after the onset of the infarction to reduce the infarct size.

Pathogenetic role of myocardial fiber disarray in the progression of cardiac fibrosis in normal hearts, hypertensive hearts and hearts with hypertrophic cardiomyopathy

To define the pathogenetic role of myocardial fiber disarray in the progression of cardiac fibrosis, the percent area of fibrosis in tissue with disarray was compared with that in tissue without disarray. Thirty autopsied hearts, 10 from patients with hypertrophic cardiomyopathy, 10 from patients with hypertension and 10 from normal adults, were studied. The percent areas of fibrosis in tissues with and without disarray were significantly different (p less than 0.01) among hearts with hypertrophic cardiomyopathy (12.6 +/- 4.0 and 8.2 +/- 3.3%), hypertensive hearts (6.6 +/- 3.6 and 2.5 +/- 1.4%) and normal hearts (2.8 +/- 1.2 and 1.0 +/- 0.4%). The percent area of fibrosis in tissue with disarray was greater than in that without disarray in all 3 groups and the ratios of these percentages were similar in the 3 groups: 2.9 +/- 4.2 in hypertrophic cardiomyopathy 2.5 +/- 1.7 in hypertensive hearts and 2.5 +/- 1.8 in normal hearts. The conclusions are: 1) disarray promotes fibrosis to a similar degree, not only in hypertrophic cardiomyopathy, but also in hypertensive hearts and normal hearts; 2) the increased level of fibrosis in hearts with hypertrophic cardiomyopathy and in hypertensive hearts, together with widespread fibrosis in hearts with hypertrophic cardiomyopathy in particular cannot be explained by disarray alone.