Dental implants. 8. Implant surgery to overcome anatomical difficulties

Autogenous grafts are considered to be the most predictable for replacement of deficient bones to facilitate implant treatment. Augmentation of soft tissue may also be required to improve aesthetics and function.     

Temporal lobe developmental malformations and hippocampal sclerosis: epilepsy surgical outcome

BACKGROUND: Temporal lobe developmental malformations coexist with mesial temporal sclerosis in the form of dual pathology with a high frequency of bilateral amygdala or hippocampal abnormalities. OBJECTIVE: The aim of this study was to correlate and compare the MRI findings and the surgical outcome in patients with temporal lobe developmental malformations (n = 20) and isolated mesial temporal sclerosis (n = 36). METHODS: MRI-based normalized volumetry of the amygdala and hippocampal formation in patients with unilateral temporal lobe developmental malformations and isolated mesial temporal sclerosis who underwent temporal lobe resections was performed. Seizure outcome was compared between groups at follow-up. RESULTS: The frequency of bilateral hippocampal or amygdala atrophy (p < 0.04) and combined hippocampal-amygdala atrophy (p < 0.02) was higher in patients with temporal lobe developmental malformations. Although no significant difference in postsurgical seizure-free status was found between the temporal lobe developmental malformations and isolated mesial temporal sclerosis groups (70% versus 91%), patients with temporal lobe developmental malformations and bilateral amygdala or hippocampal-amygdala atrophy had a significantly worse outcome (p < 0.02). CONCLUSION: Bilateral hippocampal atrophy is frequent in patients with temporal lobe developmental malformations. However, it is the presence of bilateral amygdala or amygdalo-hippocampal atrophy that is associated with a higher risk of seizure recurrence.     

Changes in iron histochemistry after hypoxic-ischemic brain injury in the neonatal rat

Iron can contribute to hypoxic-ischemic brain damage by catalyzing the formation of free radicals. The immature brain has high iron levels and limited antioxidant defenses. The objective of this study was to describe the early alterations in nonheme iron histochemistry following a hypoxic-ischemic (HI) insult to the brain of neonatal rats. We induced a HI insult to the right cerebral hemisphere in groups of 7-day-old rats. Rats were anesthetized, then their brains were perfused and fixed at 0, 1, 4, 8, 24 hr, and 1, 2, and 3 weeks of recovery. Forty-micron-thick frozen sections were stained for iron using the intensified Perls stain. Increased iron staining was first detected within the cytoplasm of cells with pyknotic nuclei at 4 hr of recovery. Staining increased rapidly over the first 24 hr in regions of ischemic injury. By 7 days recovery, reactive glia and cortical blood vessels also stained. Increased staining in gray matter persisted at 3 weeks of recovery, whereas white matter tracts had fewer iron-positive cells compared to normal. The early increase in iron staining could be caused by an accumulation of iron posthypoxicischemic injury or a change in iron from nonstainable heme iron to stainable nonheme iron. Regardless of the source, our results indicate that there is an increase in iron available to promote oxidant stress in the neonatal rat brain following hypoxia-ischemia.     

Risk factors for orofacial and limbtruncal tardive dyskinesia in older patients: a prospective longitudinal study

Although there is a consensus that orofacial and limbtruncal subtypes of tardive dyskinesia (TD) exist and may represent distinct pathophysiologic entities, few studies have examined the incidence of and risk factors associated with the development of these TD subtypes. Two hundred and sixty-six middle-aged and elderly outpatients with a median duration of 21 days of total lifetime neuroleptic exposure at study entry were evaluated at 1- to 3-month intervals. Using mild dyskinesia in any part of the body for diagnosis of TD, the cumulative incidence of orofacial TD was 38.5 and 65.7% after 1 and 2 years, respectively, whereas that of limbtruncal TD was 18.6 and 32.6% after 1 and 2 years. Preclinical dyskinesia was predictive of both orofacial and limbtruncal TD. History of alcohol abuse or dependence was a significant predictor of orofacial TD only whereas tremor was a significant predictor of limbtruncal TD only. Findings support suggestions that orofacial and limbtruncal TD may represent specific subsyndromes with different risk factors.     

Histopathology and prognosis of Wilms tumors: results from the First National Wilms' Tumor Study.

Detailed histological analysis of 427 cases entered on the first National Wilms' Tumor Study revealed that lesions with foci of marked cytological atypism (anaplasia), and those composed predominantly of sarcomatous stroma, were associated with unfavorable outcome. Twenty-five patients had anaplasia, and 24 had sarcomatous lesions of which a total of 28 (57.1%) died of tumor. Three hundred and seventy-eight patients had tumors which showed neither of these features, and only 26 (6.9%) died of tumor. Seven of ten deaths due to tumor in patients diagnosed before two years of age were associated with sarcomatous lesions. Three sarcomatous patterns were recognized, of which one, designated "clear cell" sarcoma, had a predilection for bony metastases. Using criteria defined and illustrated in this paper it is possible to identify in advance those patients likely to do poorly using current therapeutic approaches.     

Colposcopic examination of the cervix of cebus monkeys.

A total of 410 colposcopic examinations were performed on 188 female cebus monkeys that were under study to determine the oncogenic potential of herpes simplex virus type 2 in this genus. A split-cone vaginal speculum was developed that permitted good observation of the vaginal cervix in the cebus monkey. The cervical anatomy of cebus monkeys was found to differ from that of humans in that the surface of the animal cervix was more papilliform, with thinner squamous epithelium, and the squamocolumnar junction lay within the endocervical canal. Therefore, the ability to detect abnormalities in the cervical epithelium by colposcopic examination in the cebus monkey was restricted to vascular changes in the squamous epithelium. After 100 examinations, several vascular patterns were distinguishable and interpretations of these patterns were compared with cytologic findings on the same animals. Findings by both cytology and colposcopy were mild in nature; no carcinoma was detected. Colposcopic and cytologic findings correlated at a level of 84%. More abnormalities were detected with colposcopy than with use of cytologic techniques.     

Changes in the proportions of peripheral blood lymphocytes in patients with worn implants

We compared the peripheral blood and periprosthetic tissues of 53 patients at revision arthroplasty with those of 30 patients at primary arthroplasty to determine whether there is a systemic difference in lymphocytes in patients with worn hip implants. The absolute number and relative proportion of lymphocytes bearing CD2, CD3, CD4, CD8, CD16, CD19, HLA-DR, kappa and lambda antigens were compared with the levels of IL-1beta, IL-6 and PGE2 in the pseudosynovial membrane as well as with a semiquantitative estimate of metal and polyethylene particles, necrosis and chronic inflammation and the total concentration of metals within the periprosthetic tissues. There was a significant increase in the relative proportion of CD2-positive T-cells and CD16-positive natural killer cells in the peripheral blood at revision arthroplasty compared with primary arthroplasty and an increased proportion of CD8-positive T-cells and a decreased ratio of CD4 to CD8 (helper inducer/suppressor cytotoxic cells). Three control patients, who went on to have revision surgery, had values at primary arthroplasty which were similar to those of patients at the time of revision surgery. These differences did not correlate with the local concentration of metal, plastic or cement or inflammatory response or the type of prosthesis. An inverse correlation was noted between the necrosis in the periprosthetic tissue and both the local production of IL-6 and the absolute numbers of T-cells in peripheral blood. We conclude that there may be several cell-mediated systemic immune responses to aseptic loosening, at least one of which may be directly related to events in the periprosthetic tissues. We cannot exclude the possibility that the changes in the proportion of CD8-positive cells reflected a predisposition, rather than a reaction, to loosening of the implant.