Blunt, bent needle for continuous curvilinear capsulorhexis

We describe an anterior continuous curvilinear capsulorhexis (CCC) technique that uses a dull needle. The needle's blunt tip prevents inadvertent tearing of the anterior capsule, and its rough surface allows the surgeon to transmit a power vector of different amplitude and direction to the edge of the capsulorhexis to continue the tear as desired. For biomechanical reasons, we prefer an arcade-shaped CCC because this configuration provides a greater circumference than a circular CCC. The blunt needle allows one to perform a single-step capsulorhexis in a safe and controlled manner and reduces surgical time. Even in cases of white and liquified cortex, the dull needle has proved a useful, safe tool.     

Anterior capsulotomy created by radiofrequency endodiathermy and continuous curvilinear posterior capsulorhexis in a patient with intumescent cataract and primary capsular fibrosis

PURPOSE: To report a clinicopathologic correlation of angiosarcoma affecting the eyelid skin. METHODS: An 82-year-old man developed multiple bruise-like maculopapular lesions, subcutaneous nodules, and diffuse edema over his scalp, face, and eyelids. Biopsy disclosed angiosarcoma, and the patient was treated with wide-field external beam radiotherapy (5,000 cGy). RESULTS: He responded to radiotherapy with partial regression of the tumor. Twelve months later, he developed extensive lymphedema secondary to the residual tumor. He was also found to have parotid gland and bone metastases, treated with radiotherapy. The patient died of widespread bone metastases 3 months later. CONCLUSIONS: Angiosarcoma is a rare skin tumor that has a poor prognosis despite treatment. It should be considered in the differential diagnosis of eyelid tumors and edema because it may affect only the central portion of the face.     

Liquefied aftercataract: a complication of continuous curvilinear capsulorhexis and intraocular lens implantation in the lens capsule

OBJECTIVE: To compare effects of N(G)-monomethyl-L-arginine (L-NMMA; a NO synthase inhibitor) and L-arginine (a NO synthase substrate) on haemodynamics in healthy men at rest and during exercise. METHODS: We infused L-NMMA and saline placebo intravenously in two groups of eight healthy men. Each group underwent a two-phase, randomized, single-blind crossover study. Men in one group received 3 mg/kg L-NMMA and men in the other group received 6 mg/kg L-NMMA. Haemodynamic measurements were performed before, during and after a 12 min stepped exercise protocol starting 6 min after the intravenous infusion. A further six men received, according to the same study design, 30 g L-arginine over 30 min and saline placebo before exercise. Blood pressure was measured by sphygmomanometry and cardiac output by bioimpedance, allowing computation of total systemic vascular resistance index (SVRI). RESULTS: Infusion of 6 mg/kg L-NMMA into men at rest produced modest increases (compared with effect of saline placebo) in systolic and diastolic blood pressures of 4.1 +/- 1.1 and 12.6 +/- 3.5%, respectively (means +/- SEM, P < 0.01 for both comparisons) and a marked increase in SVRI of 39.2 +/- 5.2% (P < 0.01). Cardiac index and heart rate were 22.0 +/- 3.3 and 17.0 +/- 4.4% lower after administration of L-NMMA (P < 0.01 for each comparison) than after infusion of saline placebo. During exercise there was no significant difference between total SVRI after infusions of L-NMMA and saline (difference not significant, diminished with increasing exercise). Six minutes into recovery the difference between total SVRI after infusions of L-NMMA and saline reappeared with SVRI 25 +/- 6.9% higher after infusion of L-NMMA than after infusion of saline (P < 0.01). Administration of L-arginine had no significant effect on haemodynamics in men at rest, during exercise and during recovery. CONCLUSIONS: Effects of L-NMMA on total systemic vascular resistance during exercise are less marked than are those on subjects at rest, probably because vasodilatation of resistance vessels of skeletal muscle during exercise is mediated mainly by factors other than NO. Our results also suggest that NO synthesis in healthy men is not substrate limited either at rest or during exercise.     

Application of composite resin for single-appointment anterior and posterior diastema closure

Due to aesthetic and periodontal factors, patients often seek treatment to close diastemata. This condition may be eliminated by either direct or indirect techniques. Indirect techniques generally require multiple visits to facilitate the placement of laminate, crown, or bridge restorations, and involve significant financial expense. Direct techniques can be economical and successful, although they present unique challenges in the achievement of satisfactory proximal contacts and contours. This article describes three clinical techniques that may be employed to treat anterior and posterior diastemata in a single appointment.     

Hippocampal volumes in cognitively normal persons at genetic risk for Alzheimer's disease

Brain imaging techniques have the potential to characterize neurobiological changes that precede the onset of cognitive impairment in persons at risk for Alzheimer's disease. As previously described, positron emission tomography (PET) was used to compare 11 cognitively normal persons 50 to 62 years of age who were homozygous for the epsilon4 allele of apolipoprotein E and 22 persons without the epsilon4 allele with a reported family history of Alzheimer's dementia who were matched for sex, age, and level of education. The epsilon4 homozygotes had significantly reduced glucose metabolism in the same brain regions as patients with Alzheimer's dementia; the largest reduction was in the posterior cingulate cortex. As described here, magnetic resonance imaging (MRI) was used to compare hippocampal volumes in the same subject groups. The epsilon4 homozygotes showed nonsignificant trends for smaller left and right hippocampal volumes; overall, smaller hippocampal volumes were associated with reduced performance on a long-term memory test. Whereas PET measurements of cerebral glucose metabolism begin to decrease before the onset of memory decline, MRI measurements of hippocampal volume begin to decrease in conjunction with memory decline in cognitively normal persons at risk for Alzheimer's disease.     

Histology of posterior scleral foramen in normal eyes: its possible role in optic nerve damage in chronic open angle glaucoma

We examined the histologic features of the posterior scleral foramen in 27 enucleated eyes (16 during autopsy and 11 with choroidal malignant melanoma). The histologic findings of the posterior scleral foramen were similar to those in previous reports. The shape of the scleral foramen was either cylindrical or truncated, the latter occurring when the inner margin of the sclera projected with a crest-like edge pressing into the optic nerve. This configuration was encountered more frequently in the upper and lower temporal aspects of the scleral foramen in 10 eyes, while the nasal rim was free of such projection in all the eyes. We hypothesize that the effect of prolonged high intraocular pressure exerted on the axonal tissue against these crest-like edges of the non-distensible scleral foramen might be the major factor in the etiology of early arcuate nerve fiber bundle defects in primary open-angle glaucoma.     

Pharmacokinetics of intravitreal vancomycin in normal and infected rabbit eyes

The purpose of this study was to determine the pharmacokinetics governing the distribution and elimination of intravitreally injected vancomycin in normal and infected rabbit eyes. Two groups each of 36 pigmented animals were used. Group 1 served as control. In Group 2, experimental endophthalmitis was induced in the right vitreous by inoculation with Staphylococcus aureus. Once endophthalmitis developed, a vancomycin solution was injected. Four animals from each group were killed at nine time points post-injection, the vitreous and aqueous were removed, and blood samples were taken for HPLC analysis. Data analysis was performed using the RSTRIP program. The half-lives were 69 hours in normal vitreous and 14.53 hours in infected vitreous. Therapeutic drug levels were present in the vitreous 84 hours post-injection in all eyes; they were detected from 2 to 48 hours in normal aqueous but at lower levels in the infected ones. Kv and Ca/Cv ratios suggested that the primary route of elimination was across the retina and the anterior chamber in normal eyes, and via the retina in infected eyes. Results indicate that pharmacokinetic parameters change in pathological conditions, which may help establish better treatment guidelines for endophthalmitis.     

Meter-dosed, inhaled beclomethasone attenuates bronchoalveolar oxyradical inflammation in premature infants at risk for bronchopulmonary dysplasia

The object of this study was to examine the hypothesis that meter-dosed, inhaled beclomethasone administered to premature infants beginning at birth in a tapering dosage schedule over the first 12 days of life attenuates bronchoalveolar lining fluid oxyradical inflammation concomitant with modulation of bronchopulmonary dysplasia. The design of this study was an unblinded, uncontrolled phase I, pilot investigation of inhaled beclomethasone primarily examining safety and administration. The setting was a tertiary care neonatal intensive care unit. Intubated, premature infants were studied longitudinally to 36 weeks corrected gestational age. Meter-dosed, inhaled beclomethasone was administered in a tapering dosage schedule over the first 12 days of life. Endotracheal tube aspirates were collected on Days 2, 4, and 6 of life and assayed for various markers of bronchoalveolar lining fluid oxyradical stress. Infants were also assessed with regards to a number of relevant clinical variables and presence or absence of bronchopulmonary dysplasia at 36 weeks corrected gestational age. Although no differences in clinical outcome were apparent in comparing nine control infants with nine beclomethasone-treated infants, bronchoalveolar lining fluid from control infants exhibited evidence of apparent phospholipid peroxidation (enhanced polyunsaturated fatty acid consumption) on Day 2 of life compared to beclomethasone-treated infants. Significant differences were noted for percent arachidonic acid, total polyunsaturated fatty acids and ratio of polyunsaturated fatty acids, to saturated fatty acids. The ratio of monohydroxyl linolenic acid to native linoleic acid (a more specific marker of lipid peroxidation) as well as myeloperoxidase activity (a marker of neutrophil oxyradical stress) tended to be higher in the control group but did not achieve statistical significance for this small subject number study. No adverse reactions related to meter-dosed, inhaled beclomethasone were noted in the treatment group; most specifically no evidence of hypothalamic-pituitary-adrenal axis suppression was noted in either control or beclomethasone-treated infants. Meter-dosed, inhaled beclomethasone in the dosage schedule utilized was safe and appeared to moderate bronchoalveolar lining fluid phospholipid peroxidation. Small numbers of infants entered into the present investigation preclude comments on clinical efficacy because of the likelihood of a statistical type 2 error. However, additional investigations of inhaled beclomethasone initiated at birth in premature infants at risk for bronchopulmonary dysplasia, enrolling larger number of subjects and perhaps a higher dosage of beclomethasone, are warranted.     

Retinal detachment in pseudophakic eyes with and without Nd:YAG laser posterior capsulotomy

OBJECTIVE: This study aimed to determine whether the characteristics of pseudophakic retinal detachment (RD) differ in eyes with and without a neodymium (Nd):YAG laser capsulotomy to identify features that might help to treat capsulotomy patients better. DESIGN: The study design was a retrospective cohort study of 129 consecutive eyes, 61 with a capsulotomy and 68 control eyes with an intact posterior capsule, in which a primary rhegmatogenous RD developed after a strictly uncomplicated extracapsular cataract extraction and intraocular lens implantation. SETTING: The study was conducted in a primary referral center. MAIN OUTCOME MEASURES: Number, type, and location of retinal breaks and type and extent of RD were measured. RESULTS: Risk factors predisposing to RD did not differ between the capsulotomy and control group. The median interval from cataract surgery to RD was expectedly longer in the capsulotomy group (4.1 years vs. 1.5 years, P < 0.001). The mean number of retinal breaks was larger in the capsulotomy group (1.7 vs. 1.1, P = 0.05), especially in upper quadrants (82 of 103 vs. 48 of 77, P = 0.024). Capsulotomy eyes also had a trend to have more atrophic holes that caused detachment relative to horseshoe breaks (34 of 103 vs. 15 of 77, P = 0.062). The type and extent of RD were similar in the two groups. CONCLUSIONS: This pilot study suggests that atrophic holes, particularly in the superior quadrants, may lead to RD preferentially after posterior capsulotomy. Early identification and treatment of such breaks might decrease the number of pseudophakic detachments after capsulotomy.     

Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes

We should recognize that we have a responsibility to people who live outside our own borders, and view ourselves as part of the global community. Looking at China we are faced with ethical dilemmas which require consideration. First, there is the ethical dilemma of business versus health. The opening and development of the tobacco business in China, which includes vigorous marketing, is considered against the health consequences of tobacco use which is estimated to cost 600,000 lives annually in China, rising to 2 million by 2,025 without effective tobacco control programmes. A second ethical dilemma is employment versus impoverishment, in which the opportunities for work in the tobacco industry are considered against a background of malnutrition caused in part by a proportion of household budgets used to buy tobacco, and the erosion of the land, as trees are used to produce tobacco. Gains have already been made in tobacco control in China, with the way open for much development in the future.     

Alcohol use and risk of posterior subcapsular opacities

We conducted a follow-up study of surgical cases of posterior subcapsular cataracts and their controls to evaluate the possible association of alcohol intake and posterior subcapsular opacities. Two hundred thirty-eight cases and controls were interviewed. Current alcohol intake and usual and maximum weekly consumption ever were assessed. In this population, 57% of the cases and 56% of the controls were nondrinkers, 22% of the cases and 36% of the controls had an average of seven or fewer drinks per week, and 17% of the cases and 8% of the controls had more than seven drinks per week. A matched pair analysis controlling for other known risk factors showed an increased risk associated with heavy alcohol use. Heavy drinkers were more likely to be cases than were nondrinkers (odds ratio, 4.6; P < .05), and light drinkers were not at an increased risk. This result suggests that heavy alcohol consumption may increase the risk of posterior subcapsular cataract.     

广钢转炉连铸机二冷自动配水

本文叙述了广钢转炉厂1#连铸机使用MICROMAX2--综合控制系统来实现二冷自动配水的运行情况和本系统的工作原理等,并对连铸机在实现二冷自动配水后的实际效益进行估算.     

The evaluation of normal corneal topography in emmetropic eyes with computer-assisted videokeratography

Positron emission tomography (PET) has been widely used in the study of stroke and related cerebrovascular diseases. It has shown the various stages leading to cerebral infarction and defined the significance of the ischaemic penumbra. PET scan can predict the clinical outcome of patients with acute ischaemic stroke. Several types of diaschisis can also be demonstrated by PET. They reflect different pathophysiological changes in supratentorial infarcts. Post-apoplectic seizures are shown to increase the ischaemic damage in the affected cerebral hemisphere. PET has contributed also to the concept of multi-infarct dementia, although the significance of chronic ischaemia in the pathogenesis of vascular dementia has not been fully investigated.     

Secondary osteoporosis and the risk of vertebral deformities in women

Recent reports have indicated that large-dose opiate anesthesia can increase neuronal injury in rats subjected to forebrain ischemia. However, most episodes of cerebral ischemia in the operating room setting are focal in nature, and the influence of large-dose opioid administration on the tolerance of the brain to focal cerebral ischemia has not been studied. Accordingly, we undertook the present study to evaluate the effect of fentanyl administration on outcome after focal cerebral ischemia. Three groups of fasted Wistar-Kyoto rats (awake, fentanyl, and isoflurane groups; n = 20 per group) were anesthetized with isoflurane (2.5% end-tidal). Pericranial temperature was servocontrolled at 37.0 degrees C. After surgical preparation fentanyl 50 microg/kg was administered IV over 10 min in the fentanyl group. Thereafter, an infusion was established at a rate of 50 microg x kg(-1) x h(-1). The end-tidal concentration of isoflurane was then reduced to 1.1%, one minimum alveolar anesthetic concentration (1 MAC) in all groups. Occlusion of the middle cerebral artery was achieved by advancing a 0.25-mm filament into the anterior cerebral artery via the common carotid artery. In the fentanyl and awake groups, isoflurane administration was then discontinued. In the isoflurane group, isoflurane anesthesia was maintained at 1.0 MAC. After 90 min of focal ischemia, the filament was removed, and the animals were allowed to recover. Seven days later, the volume of cerebral infarction in the animals was determined by image analysis of hematoxylin and eosin-stained coronal brain sections. There was no difference in the infarct volume between the fentanyl and awake groups. The infarct volume was the least in the isoflurane group. The results confirm the ability of isoflurane to reduce brain injury caused by focal cerebral ischemia. Fentanyl neither increased nor decreased brain injury compared with the awake unanesthetized state. IMPLICATIONS: Fentanyl is commonly used in surgical procedures in which there is a substantial risk of focal cerebral ischemia. Fentanyl did not affect cerebral injury produced by focal ischemia in the rat. The data suggest that, in doses that produce respiratory depression and muscle rigidity, fentanyl does not reduce the tolerance of the brain to a focal ischemic insult.     

基于有效拉速和有效过热度的连铸二冷控制模型

针对连铸生产中拉速及浇注温度波动频繁,导致静态二冷配水控制下铸坯表面温度波动过大的问题,提出了一种基于有效拉速、有效过热度的新型二冷控制模型.该模型不需要在线实时计算温度场,只需要在已有参数控制模型的基础上,实时计算有效拉速及有效过热度即可对连铸坯的表面温度进行很好的控制.计算机仿真实验表明,该控制模型对连铸过程中拉速及过热度的变化具有良好的适应能力,满足连铸生产的要求,而且模型简单易行.     

Sclera fixation of posterior chamber lenses in vitrectomized eyes. Perfluorocarbon as an operative aid

OBJECTIVE: To discuss a case of chondromyxoid fibroma presenting with low back pain. CLINICAL FEATURES: A 50-yr-old man had an 8-yr history of low back pain. This was diagnosed and treated as arising from the disc and caused by spinal stenosis. Magnetic resonance imaging findings supported the clinical findings. Years later, a plain radiograph of the pelvis revealed an incidental abnormality of the right ilium, and the patient was subsequently referred to a musculoskeletal tumor center for treatment. INTERVENTION AND OUTCOME: The lesion was surgically removed and the defect was reconstructed via bone allograft. CONCLUSION: Such tumors are a rare cause of back pain. Tumors of the pelvis can at times present as back pain. In cases of refractory back pain, an X-ray of the pelvis can be a useful screening investigation. Chondromyxoid fibromas are rare tumors best treated by excision if they are amenable or by curettage and bone grafting procedures.     

Comparative study of postoperative analgesia with methadone and fentanyl in continuous peridural perfusion

OBJECTIVE: To determine whether continuous epidural perfusion of fentanyl, which is more liposoluble than methadone, provides a similar level of analgesia with fewer side effects than methadone administered by the same route for postoperative pain. PATIENTS AND METHODS: Prospective double blind study of 40 patients, randomly assigned to two groups. Group F (n = 20) received 300 micrograms-1200 micrograms/24 h in epidural perfusion. Group M (n = 20) received 9 mg-18 mg/24 h in epidural perfusion. In both cases treatment was for pain in the first 72 h after abdominal surgery. Analgesia quality was evaluated on a visual analog (VAS) scale from 1 to 10 at rest and moving. Need for complementary analgesia was also recorded, as were side effects related to the technique. RESULTS: Quality of analgesia was good and similar which both drugs. Postoperative pain did not surpass 3 on the VAS at rest or 4.5 while moving, although group F patients' need for complementary analgesia was significantly greater (p < 0.05). The incidence of hypoxemia was greater in group M than in group F (p = 0.05). CONCLUSIONS: Continuous epidural perfusion of fentanyl provides good analgesia and is associated with less hypoxemia than is methadone.     

Growth in literacy and cognition in bilingual children at risk or not at risk for reading disabilities.

This study investigated growth in reading, vocabulary, and memory in children (ages 5 to 10) learning English as a second language identified at risk for reading disabilities (RD). A growth curve analysis showed that RD children were significantly below children not at risk in English and Spanish reading, Spanish short-term memory (STM), Spanish comprehension, and English and Spanish working memory (WM). RD children were also inferior on growth measures of English and Spanish WM and Spanish STM. Growth on measures of Spanish vocabulary, reading, STM, and WM accounted for 12% of the variance in predicting growth in English reading. However, only Spanish measures of WM growth contributed unique variance. The results show that growth in WM in the primary language predicts growth in second-language reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)