Proximally porous-coated ingrowth prostheses: limits of use

Callaghan has suggested that the most important factor in obtaining optimal results after total hip arthroplasty may be the ability to determine when to use cemented or cementless fixation. This article has presented the indications and relative contraindications for use of proximally porous-coated prostheses. Midterm results suggest that with appropriate patient selection, excellent clinical results can be achieved with currently available proximally porous-coated prostheses. Use of proximally coated prostheses is indicated for primary total hip arthroplasty in patients aged >70 years with good bone stock. Relative contraindications are based on interference with bone ingrowth or with the ability to achieve a congruent fit, both of which preclude establishment of rigid initial stability. These conditions include metabolic bone disease such as osteoporosis, osteomalacia, Gaucher's disease, sickle cell disorders, and Paget's disease; significant anatomical distortion, as seen in developmental dysplasia of the hip with anteversion, prior osteotomy, or intertrochanteric fracture; Dorr type C bone; and current treatment with radiation, chemotherapy, indomethacin, or diphosphonates. The same relative contraindications to use are applicable in revision situations. Further, proximally porous-coated prostheses should not be used for revision arthroplasty in the setting of massive bone loss, limited life expectancy, or inability to participate in protected weight bearing. These devices may be used successfully in revision arthroplasty when the hip has minimal or moderate bone loss, and occasionally in the setting of severe bone loss. As further information is revealed through the long-term (10-20 years) results of proximally coated prostheses, further refinements and knowledge of the indications and contraindications for the use of these prostheses will be revealed.     

Immunocytochemical Study of Cells in the Vitreous of Proliferative Virteoretretinopathy

Purpose: To identify the cellular components of vitreous samples obtained during vit-rectomy for proliferative vitreoretinopathy(PVR).Methods: With the use of three intermediate filament (IF) proteins, vimentin, glialfibrillary acidic protein (GFAP), and cytokeratin (CK), cytocentrifuge slides of 14fresh vitreous aspirates were detected with immunohistochemical technique.Results: All the specimens contained epithelial-like proliferative cells with or withoutpigment and some membrane-like pieces. Immunocytochemical staining showed that76.0-90.0% cells stained for CK, 17.4-29.6% cells expressed GFAP, and 80.1-91.0% cells were positive for vimentin.Conclusions : Majority of cells in the vitreous samples originated from retinal pigmentepithelial cells (RPE) and glial cells in PVR. Expression of IF proteins may be determinedby tissue of origin and local microenvironment. Eye Science 1999 ; 15; 13 - 16.     

Incidence of presumed cytomegalovirus retinitis in HIV-infected pediatric patients.

INTRODUCTION: Large population studies of adult patients suggest an incidence of cytomegalovirus (CMV) retinitis as high as 19% to 20% as a late complication of adult HIV infection. We conducted this prospective study of a large cohort of HIV-infected children to determine the incidence of CMV retinitis in HIV-infected children. METHODS: From January 1984 to August 1997, 173 HIV-infected children were followed up for an average of 55.3 months (13-164 months). The patients were seen in the Department of Pediatrics at least once every 6 months. Ophthalmologic examinations were initiated when a patient's CD4 count dropped below 50 or sooner if required for ophthalmologic or other indications. Ophthalmologic examination was then repeated every 6 months. RESULTS: A total of 116 (67%) of 173 patients underwent ophthalmologic examination. Four (3.4%) of 116 patients had CMV retinitis at a mean time of 17.3 months (8-38 months) after their CD4 counts dropped below 20. None of the 4 patients with CMV retinitis had subjective visual complaints despite advanced retinitis. Three patients had bilateral and 1 patient had unilateral CMV retinitis. CONCLUSIONS: CMV retinitis occurred infrequently in HIV-infected pediatric patients and was diagnosed only in patients with a CD4 count below 20. Routine ophthalmologic screening examinations may not be necessary in pediatric patients until the CD4 count is below 20. Because children may not complain of decreased vision, at-risk children should undergo frequent ophthalmologic examination.     

Regulation of complement activation by C-reactive protein.

C-reactive protein (CRP) is an acute-phase serum protein and a mediator of innate immunity. CRP binds to microbial polysaccharides and to ligands exposed on damaged cells. Binding of CRP to these substrates activates the classical complement pathway leading to their uptake by phagocytic cells. Complement activation by CRP is restricted to C1, C4, C2 and C3 with little consumption of C5-9. Surface bound CRP reduces deposition of and generation of C5b-9 by the alternative pathway and deposition of C3b and lysis by the lectin pathway. These activities of CRP are the result of recruitment of factor H resulting in regulation of C3b on bacteria or erythrocytes. Evidence is presented for direct binding of H to CRP. H binding to CRP or C3b immobilized on microtiter wells was demonstrated by ELISA. Attachment of CRP to a surface was required for H binding. H binding to CRP was not inhibited by EDTA or phosphocholine, which inhibit ligand binding, but was inhibited by a 13 amino acid CRP peptide. The peptide sequence was identical to the region of CRP that showed the best alignment to H binding peptides from Streptococcus pyogenes (M6) and Neisseria gonorrhoeae (Por1A). The results suggest that CRP bound to a surface provides secondary binding sites for H resulting in greater regulation of alternative pathway amplification and C5 convertases. Complement activation by CRP may help limit the inflammatory response by providing opsonization with minimal generation of C5a and C5b-9.     

The influence of the route of administration: a comparative study at steady state of oral sustained release morphine and morphine sulfate suppositories

Steady state pharmacokinetics of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were investigated in 6 patients with intractable cancer pain administered orally with MST (Mundipharma, Limburg, Germany) and, subsequently, rectally with MSR to make a judgment whether orally administered morphine can be replaced by rectally administered morphine. The parent drug and glucuronide metabolites were measured simultaneously using high-performance liquid chromatography (HPLC) and native fluorescence detection. The mean morphine area under the curve (AUC) value (0-8 h) was smaller (434.3 +/- 170.2 nmolL(-1)h) in the oral administration than in the rectal administration (574.8 +/- 285.0 nmolL(-1)h) (p < 0.05). The rectal administration resulted in less production of M3G and M6G. There were no significant differences in the mean steady state concentrations (C(ss)) of morphine, M3G, and M6G between the oral and rectal administrations (p > 0.05). The median AUC ratio--M3G/M and M6G/M, 12.58 and 1.85--following MSR rectal administration was smaller than following MST oral administration in 6 patients (19.97 and 2.59; p < 0.05), whereas the median AUC ratio M3G/M6G in the rectal dosing was 6.24 (range 5.2-7.6) was almost the same as the median ratio M3G/M6G in the oral dosing was 6.49 (range 5.8-8.5; p > 0.1). Four of the 6 patients had a greater Cmax of M3G and M6G after oral administration than after rectal administration. The same 4 had lower fluctuation rates for morphine, M3G (p < 0.05), and M6G (p < 0.05) after rectal administration. Therefore, during chronic morphine treatment, it still seems difficult to decide whether oral administration can be replaced by rectal administration.     

药流与负压吸宫法的效果和可接受性研究

研究的目的:比较RU486/Cytotec药物和负压吸宫术两种流产方法的效果,以及医学的和个人的可接受性.对象为通过咨询,介绍两种流产方法后,让对象自愿选择而组成.年龄在20～34岁.药物组100例,闭经35～42天,第1天口服RU486 600mg,第3天服Cytotec(PGE1)0.4mg,第17、43天回医院随访.手术组100例,闭经≤56天,负压吸宫术后第14、43天回医院随访.结果:完全流产率药物组为89%,手术组为100%.对象选择这两种流产方法的主要原因:药物组94%的人认为痛苦少,手术组的55%认为手术快、节省时间,而且手术同时可取出或放置宫内节育器(占45%).结论:RU486/Cytotec药物流产和负压吸宫术在各自适合的人群中都具有高度的可接受性.两种方法各具优缺点,不能相互取代,二者相辅相成,取长补短,将使终止妊娠的措施更为安全     

The Cerebral Cortex of the Rat and Visual Attentional Function: Dissociable Effects of Mediofrontal, Cingulate, Anterior Dorsolateral, and Parietal Cortex Lesions on a Five-Choice Serial Reaction Time Task

Dissociable effects of bilateral excitotoxic lesions of differentregions of the rat neocortex, including medial prefrontal andanterior cingulate cortices, were investigated in a five-choiceserial reaction time task that provides several indices of theaccuracy and speed of attentional function. Whereas medial prefrontalcortical lesions impaired performance of the task as revealedby a reduction in choice accuracy, an increase in the latencyto respond correctly to the visual target and enhanced perseverativeresponding, lesions of the anterior cingulate cortex specificallyincreased premature responding. By contrast, lateral frontalcortical lesions did not significantly disrupt baseline performanceof the task, but rather increased the latency to respond correctlyto the visual target during various behavioral manipulations,for example, when the length of the intertrial interval wasvaried unpredictably and during interpolation of distractingbursts of white noise. Lesions of the parietal cortex failedto disrupt any aspect of task performance investigated. These behavioral effects in the five-choice task were comparedwith the effect of these same lesions on acquisition and retentionof a one-trial passive avoidance task. The main finding fromthis paradigm was that lesions of the lateral frontal cortexproduced a significant disruption to the retention of passiveavoidance, which stands in marked contrast to the successfulretention observed by animals of the other lesion groups. Inaddition, this pattern of results reveals that the "disinhibitory"effect of cingulate cortex lesions are relatively specific tothe five-choice attentional task. Finally, the results of the present study are compared withthe findings of previous experiments using the five-choice task,which have examined the effect of selective manipulations ofthe ascending noradrenergic, cholinergic, dopaminergic. andserotonergic projections. In particular, the deficits in attentionalfunction observed following cholinergic lesions of the nucleusbasalis magnocellularis appear to be attributable to cholinergicdenervation of the medial frontal cortex. These results arediscussed in terms of the role of parallel distributed neuralsystems within the neocortex that mediate continuous attentionalperformance in the rat.     

Vascular and electromyographic responses evoked in forearm muscle by isometric contraction of the contralateral forearm

There is controversy over whether isometric contraction of the forearm evokes vasoconstriction or vasodilatation in the muscles of the contralateral forearm. In the present study we have investigated in normal man, the effects of isometric contraction of one arm at 75, 50 and 25% maximum voluntary contraction (MVC) on arterial pressure, heart rate, blood flow and vascular resistance of the contralateral forearm and on electromyographic (EMG) activity recorded from that same arm with sensitive, surface electrodes.When EMG activity was not being recorded from the resting arm, isometric contraction of the contralateral arm for 2 min evoked increases in arterial pressure and heart rate whose magnitudes were graded with % MVC and an increase in forearm blood flow and a decrease in forearm vascular resistance at 75, 50 and 25% MVC, indicating vasodilatation. Further experiments in which EMG activity was recorded from the resting arm demonstrated that the decrease in forearm vascular resistance evoked by 75% MVC was associated with a substantial increase in EMG activity of the extensor and flexor muscles of that arm. By contrast, when forearm contraction was performed at 75% MVC whilst subjects viewed the EMG activity in the resting arm on an oscilloscope and kept EMG activity minimal, vascular resistance increased in that arm, indicating vasoconstriction. Further, when subjects performed contraction at 25% MVC whilst showing minimal EMG activity in the contralateral arm, vascular resistance in that same arm increased (from 78 ± 16 to 124 ± 29 mmHg/ml/min/100 ml tissue). These results are discussed in relation to those of previous studies. We propose, that in normal man, isometric contraction of the forearm evokes primary vasoconstriction in the muscles of the contralateral forearm, but that this response may be overcome by muscle vasodilatation occurring secondary to unintended muscle contraction or as part of the alerting response to acute stress.     

Effect of cimetidine on wedged hepatic venous pressure in cirrhotic patients

According to our supposition that "humoral mechanism" plays an important role in the pathogenesis of portal hypertension due to cirrhosis, antagonists to some of humoral substances would lower the portal pressure in cirrhotic patients. Wedged hepatic venous pressure (WHVP) was used as an indicator for changes of portal pressure. Cimetidine was given intravenously to 8 cirrhotic patients, in whom an average lowering of 0.72 kPa (7.3 cm H2O) of WHVP was observed subsequently. This change was of clinical significance as compared with the previous results of splenorenal shunting operations.