Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

骨肉瘤成骨细胞表型与临床因素的相关性研究

目的采集手术切除未经培养的骨肉瘤标本,研究肿瘤中成骨细胞的分化及其与临床因素的关系。方法观察骨肉瘤中成骨细胞相关基因表达的频率、特异性,以及骨肉瘤成骨细胞表型与生物学行为的关系。应用RT-PCR方法研究48例骨肉瘤标本的碱性磷酸酶(ALP)、骨钙素(OC)和骨桥蛋白(ON)的mRNA转录。磷酸甘油酸激酶(PGK)被用于内参照。结果在大多数骨肉瘤标本中可以发现ALP或OC的mRNA转录(分别为93.75%,79.17%)。在所有的肉瘤检测中均可发现ON的mRNA转录。在骨肉瘤的成骨细胞亚型中可见到ALP和OC的高水平表达。肺转移瘤OC的mRNA表达弱于原发灶。肿瘤细胞有高水平OC表达的病例组有较高的生存率(P=0.045)。结论OC是目前最好的成骨细胞特异性标记物,将来可能用于检测骨肉瘤患者外周血中循环的肿瘤细胞。     

A comparison of placement methods using a two-in-one dentin pin

Experiments were performed to determine the effect of pin channel preparation with standard and reduction speed handpieces, and pin seating by hand and with motor drive. The greatest retention was achieved by preparation with a standard handpiece at 6000 rpm, and manual pin placement with a hand driver. The most consistent retention values were achieved using the reduction handpiece. All preparation and placement combinations examined produced a clinically acceptable result.     

Are ADDH and ADHD the same or different?

To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.     

Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials

BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.      

Evaluation of Tissue-Engineered Skin (Human Skin Substitute) and Secondary Intention Healing in the Treatment of Full Thickness Wounds after Mohs Micrographic or Excisional Surgery

BACKGROUND: Human Skin Substitute (Apligraf, Organogenesis, Inc., Canton, MA) is a bi-layered tissue-engineered living biological dressing developed from neonatal foreskin. It consists of a bovine collagen matrix containing human fibroblasts with an overlying sheet of stratified human epithelium containing living human keratinocytes. Human Skin Substitute (HSS) appears to be immunologically inert, and has shown usefulness in the treatment of chronic and acute wounds. OBJECTIVE: Primary objectives were to evaluate the safety and efficacy of HSS in the treatment of full-thickness wounds in a prospective case series. Secondary objectives were to determine the rate of complete wound reepithelialization, incidence of complete wound healing, pain at wound site, overall cosmetic outcome, and patient satisfaction. METHODS: Fourteen patients were enrolled in the study, of which 12 were evaluable. HSS was applied in a blinded fashion to 6 of the patients immediately following Mohs or excisional surgery for skin cancer. The remaining 6 patients were allowed to heal by secondary intention. Both groups were evaluated at weekly appointments until complete reepithelialization occurred. During each evaluation, wound quality was assessed through the Vancouver Burn Scar Assessment Scale by the investigator and an independent blinded dermatologist. The investigator, blinded observer, and patient further evaluated the cosmetic outcome of the wound through the use of a Visual Analog Scale over a 6-month period. RESULTS: HSS patients and secondary intention patients were equivalent in comorbid factors such as pain, erythema, edema, exudate, infection, or hematoma between the groups. The incidence of complete wound healing at 6 months was 100% for both groups. Both groups also appeared to heal at similar rates, as defined by the complete reepithelialization of the wound. HSS patients ultimately resulted in more pliable and less vascular wounds as defined by the Vancouver Burn Scar Assessment Scale. Patient satisfaction with cosmetic outcome in both groups was positive at 6 months. CONCLUSIONS: HSS appears to be a safe, well-tolerated biological dressing with equivalent comorbid factors to secondary intention healing. HSS, however, seems to produce a more pliable and less vascular scar than those developed through healing by secondary intention. HSS also appears to produce more satisfactory cosmetic results when compared to secondary intention healing.     

Nicotine vs placebo gum in general medical practice

Three hundred fifteen smokers who attended a family practice clinic and wished to quit smoking were assigned in a random, double-blind manner to receive either nicotine (2 mg) or placebo gum. Smokers initially received brief advice from a physician and nurse, a slide presentation and written materials (29 to 35 minutes), and a single follow-up visit (12 to 20 minutes) one week after cessation. After corrections for marital status and income, 10% of those who received nicotine gum and 7% of those who received placebo gum reported continuous abstinence for 11 months and passed observer and biochemical verification (this difference was not statistically significant). We conclude that, when used in a nonselected group of smokers along with a brief intervention in a general medical practice, the pharmacologic effects of nicotine gum to increase cessation are either small or nonexistent.     

Convergence of occipital nerve and superior sagittal sinus input in the cervical spinal cord of the cat

Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches.