Computer networks as social networks.

Computer networks are inherently social networks, linking people, organizations, and knowledge. They are social institutions that should not be studied in isolation but as integrated into everyday lives. The proliferation of computer networks has facilitated a deemphasis on group solidarities at work and in the community and afforded a turn to networked societies that are loosely bounded and sparsely knit. The Internet increases people's social capital, increasing contact with friends and relatives who live nearby and far away. New tools must be developed to help people navigate and find knowledge in complex, fragmented, networked societies.

Divergent cortical connections to entorhinal cortex from area TF in the macaque.

The entorhinal cortex (EC) is an important component of the medial temporal lobe memory system in the primate and is often viewed as a "gatekeeper" area that passes on highly convergent cortical inputs toward the hippocampus. Further analysis of these connections at a microcircuitry level regarding the actual size and shape of arbors and terminations is not yet available, but may contribute to understanding the role of the EC in memory or other functions. The main emphasis of this report was on serial section analysis of anterogradely labeled axons that project from area TF (lateral parahippocampal cortex; Bonin and Bailey, 1947) to the EC (n = 12). By way of evaluating network organization, other projections from area TF--to TH (in the medial parahippocampal gyrus; n = 5) and to posterior visual areas (n = 3)--were also investigated. All three systems were found to terminate heavily in layer 1, as expected from previous investigations, but some terminations were verified in layer 6 of the EC as well. This technique further demonstrated that terminal fields are widely divergent and elongated. In the EC, terminal fields extended over 6-11 mm and spanned multiple cell islands and interislands. These axons resemble "feedback" cortical connections by virtue of their layer 1 terminations and their markedly divergent geometry, but not by their origin from layer 3. Spatially extended terminal fields recall the nontopographic, distributed character of olfactory connections and raise questions of how these features might be related to the memory functions attributed to medial temporal regions.

Bilateral (mirror-image) aneurysms at the origin of the posteroinferior cerebellar artery: case report.

OBJECTIVE AND IMPORTANCE: This case demonstrates mirror-image aneurysms at the origin of the posteroinferior cerebellar arteries. To the best of our knowledge, this location has not been previously described. Identification of this entity is important for surgical planning. CLINICAL PRESENTATION: The patient presented with a history of a sentinel headache 1 week before his Grade I subarachnoid hemorrhage occurred. Before operative intervention, the patient developed acute deterioration of his mental status from hydrocephalus. After appropriate treatment for the hydrocephalus, he maintained a stable neurological course throughout evaluation and therapy. INTERVENTION: The patient underwent bilateral clipping of his aneurysms in a prone position without consequence. CONCLUSION: This case demonstrates a highly unusual mirror-image aneurysm of the proximal posteroinferior cerebellar arteries. Although multiple aneurysms are commonplace, to the best of our knowledge, this is the first reported case of bilateral posteroinferior cerebellar artery aneurysms at their origin. Also, the surgical approach is unique and allows bilateral clipping at the same operative setting.

The differences in electroencephalographic changes in patients undergoing carotid endarterectomies while under local versus general anesthesia.

OBJECTIVE: This study compared the electroencephalographic (EEG) changes occurring during carotid occlusion in 225 consecutive patients undergoing carotid endarterectomies performed by two surgeons, one using local and the other using general anesthesia. METHODS: A retrospective review of patients undergoing carotid endarterectomies for carotid occlusive disease was conducted. EEG changes associated with intraoperative ischemia (decreased amplitude, generalized slowing, and loss of fast activity) resulting in the need for an indwelling arterial shunt were recorded for the two anesthesia groups. To determine the similarities or differences between the two groups, the groups were compared regarding age, risk factors, and indications for surgery. RESULTS: Significant EEG changes were noted in 6 of 96 patients (6.3%) in the local anesthesia group versus 19 of 121 patients (15.7%) in the general anesthesia group. EEG changes consisted solely of generalized slowing in the local anesthesia group, whereas a more varied spectrum was observed in the general anesthesia group. The two groups were similar regarding age and risk factors. Although the local anesthesia group had more asymptomatic patients, symptomatic patients did not have a greater incidence of EEG changes. CONCLUSION: There is a large difference in EEG changes potentially requiring shunt placement in patients undergoing surgery while under local (6.3%) versus general (15.7%) anesthesia. This could not be explained based on age, risk factors, interpretation of EEG findings, or indications between the two groups. We conclude that EEG monitoring may be insensitive and may fail to detect ischemia in patients who are under regional anesthesia. Alternately, the presence of general anesthetics may alter the character of the EEG findings and increase the sensitivity of EEG monitoring to ischemic events.

A combined surgical-endovascular device concept for giant aneurysm neck occlusion.

PURPOSE: In this report, we describe a new multimodality device concept for occluding giant aneurysms. The device is designed to exploit the advantages, and avoid the disadvantages, of conventional microneurosurgery and interventional neuroradiology methods. CONCEPT: Our device concept involves surgically placing small permanent magnets, incorporated into a partially occluded magnetic clip, about the extraluminal neck without mechanically compromising the perforating vessels. These magnets serve as optimally positioned anchor points for ferromagnetic materials subsequently introduced via the endovascular route. RATIONALE: Currently, neurosurgical extraluminal obliteration of giant aneurysms is achieved by mechanically closing the aneurysm neck with metal clip blades, which is a technique that risks inadvertent occlusion of critical perforating vessels. Perforating vessel strokes can largely be avoided using endovascular aneurysm occlusion methods. However, in the setting of the giant aneurysm, these endovascular techniques are associated with high rates of incomplete occlusion. DISCUSSION: Preliminary feasibility tests of this concept were conducted using a simple prototype constructed in our laboratories.

Health care and consumer choice: medical and alternative therapies.

This paper reports on research conducted in a large Canadian city during 1994-1995. The study examines the motivations of patients who choose to seek care from one of five different types of practitioners: family physicians, chiropractors, acupuncturists/traditional Chinese doctors, naturopaths and Reiki practitioners. We use the Andersen socio-behavioural model to help explain why people choose orthodox medicine or a type of alternative care. The data are derived from face to face interviews with 300 patients: 60 from each of the five modes of treatment. The findings demonstrate that this model can explain the use of alternative as well as orthodox medical services. Patients choose specific kinds of practitioners for particular problems, and some use a mixture of practitioners to treat a specific complaint. The choice of type of practitioner(s) is multidimensional and cannot solely be explained either by disenchantment with medicine or by an "alternative ideology".

Complications of posterior articular mass plate fixation of the subaxial cervical spine in 43 consecutive patients.

STUDY DESIGN: A retrospective study evaluating the complications in 43 consecutive patients treated with posterior lateral mass plate fixation of the subaxial cervical spine. OBJECTIVES: To determine the surgical complications of applying posterior lateral mass plates, to correlate complication rate with surgical technique, and to determine fusion rate. SUMMARY OF BACKGROUND DATA: Posterior cervical plate stabilization is a viable alternative to more traditional wiring techniques. Advantages include superior internal stability and no requirement for intact posterior spinal elements. METHODS: Records of 43 consecutive patients who underwent posterior articular mass plate fixation were independently reviewed to identify associated complications. The average follow-up was 25 months (range, 1 to 63 months). The most common indications for surgery were posttraumatic instability (n = 22) and instability after multilevel laminectomy (n = 14). Four patients had difficult spinal disorders requiring a combined anterior and posterior approach. RESULTS: Two hundred eighty-one screws were inserted in the cervical spine (average, 7 screws per patient). There were no complications associated with placement of the screws (i.e., root injury or vertebral artery injury). Complications included two cases in which patients had superficial wound infections and one in which the patient had a spinal epidural hematoma requiring evacuation. In one patient, hardware failure required an anterior approach to correct a progressive angulation. CONCLUSIONS: With the authors' surgical technique, lateral mass plate fixation is safe and effective. There were no nerve root or vertebral artery injuries.

Complementary and alternative groups contemplate the need for effectiveness, safety and cost-effectiveness research.

OBJECTIVE: To examine the views of complementary and alternative medicine (CAM) groups on the need to demonstrate the effectiveness, safety and cost-effectiveness of their therapies and practices. DESIGN: Qualitative interviews were conducted with 22 representatives of three CAM groups (chiropractic, homeopathy and Reiki). Qualitative content analysis was used to identify similarities and differences among and across groups. SETTING: Ontario, Canada. RESULTS: There were striking differences in the views of the three sets of respondents. The chiropractors agreed that it was essential for their group to provide scientific evidence that their interventions work, are safe and cost-effective. The leaders of the homeopathic group were divided on these points and the Reiki respondents showed virtually no interest in undertaking such research. CONCLUSIONS: CAM groups that are more formally organized are most likely to recognize the importance of scientific research on their practices and therapies.

Who seeks alternative health care? A profile of the users of five modes of treatment.

This article compares the social and health characteristics of patients of five kinds of practitioners: family physicians (used as a baseline group); chiropractors; acupuncturist/traditional Chinese medicine doctors; naturopaths; and Reiki practitioners. The data were gathered in a large Canadian city during the period 1994 to 1995. Face-to-face interviews were conducted with 300 patients (60 from each type of treatment group). While the most striking social and health differences occur between patients of family physicians and the patients of alternative practitioners, significant differences are also evident between the different groups of alternative patients. Reiki patients, for example, have a higher level of education and are more likely to be in managerial or professional positions than other alternative patients. The profiles presented here indicate that users of alternative care should not be regarded as a homogeneous population. The findings also show that almost all alternative patients also consult family physicians. The pattern revealed is one of multiple use: patients choose the kind of practitioner they believe can best help their particular problem.

Forecasting bed needs and recommending facilities plans for community hospitals: a review of past performance.

A university-based hospital consulting group reviewed six studies of Michigan hospitals retrospectively in 1975. The studies represented all those done between 1967 and 1971 requiring forecasts of acute bed supply and service needs. The original studies developed forecasts using empirical studies of patient origin and rigorously prepared authoritative forecasts of county populations. The 1975 review compared forecasts of population, service population, and bed need against current values and also interviewed clients to assess retrospective satisfaction with the recommendations. Although the consultants strove steadily to minimize the bed supply and base population forecasts were accurate, the studies overestimated bed needs. Further, the clients were often dissatisfied with the original recommendations, and frequently acted to exceed them. Comparing the 1975 actual with what would now be recommended by the consultant indicates that the "error" cost the communities about $50 per person per year.

Midline anterior craniofacial approach for malignancy: results of en bloc versus piecemeal resections.

Thirty consecutive cases of midline anterior craniofacial procedures for the treatment of malignant neoplasms arising from the paranasal sinuses were reviewed. Posterior and lateral base craniofacial procedures were specifically excluded. This review compares the results, in terms of survival and major complication rate, between en bloc and piecemeal resections. The average follow-up was 4 years and 3 months. Sixteen patients were treated with an en bloc resection. The major complication rate was 31%. One-year survival rate was 94% for the en bloc resection group, 67% for patients with positive margins, and 100% for patients with clear margins. Three-year survival for en bloc resection dropped to 56, 33, and 67%, respectively. Fourteen patients were treated with piecemeal resections. The major complication rate was 21%. One-year survival rate was 83% for the piecemeal resection group, 60% for patients with positive margins, and 100% for patients with clear margins. Three-year survival dropped to 70, 60, and 80%, respectively. Although it is considered desirable to obtain an en bloc resection in some craniofacial procedures, we conclude that a piecemeal resection is a viable alternative in situations where an en bloc procedure is difficult to obtain safely.