The International Normalized Ratio as a measure of anticoagulation: significance for the management of the dental outpatient.

Susceptibility to bleeding in the patient treated with coumarin derivatives poses difficult management issues for the dentist. Classic monitoring for anticoagulation relied on the prothrombin time, but reagent variability issues have caused the emergence of the International Normalized Ratio (INR) as an alternative, and possibly more reliable, laboratory test for the assessment of a patient's anticoagulation status. The literature suggests that an INR range of 1.5 to 2.5 represents the most appropriate level of anticoagulation for the surgical patient. That is, at this INR, some protection is afforded against thrombo-embolic events without significantly sacrificing effective post-operative hemostasis. Since the patient with an INR value within the recommended range is still anticoagulated, he/she is still at risk for post-operative bleeding. Adherence to local hemostatic measures--such as pressure, topical thrombin, alveolar-placed resorbable sponges, and primary wound closure--offers the patient important adjunctive protection against post-operative bleeding.

Infective endocarditis in a patient with Hodgkin's lymphoma: a case report.

A common sequela of certain malignancies is nonbacterial thrombotic endocarditis (NBTE), a phenomenon in which sterile fibrin/platelet aggregates are deposited onto normal cardiac valves. These verrucae represent a predisposing factor for the initiation of infective endocarditis following a bacteremia. This paper presents a case history which is highly suggestive of infective endocarditis which occurred as a result of multiple odontogenic abscesses in a patient with Hodgkin's lymphoma. The case illustrates the important role that the dentist can play in the management of cancer patients and emphasizes a wholistic concept of medical care in which the dentist is an integral member of the health-care team.

An event-related potential study of semantic congruity and repetition in a sentence-reading task: effects of context change.

This experiment examined the joint effects of semantic congruity and repetition on event-related brain potentials (ERPs) elicited in a sentence priming task. In an initial training phase, subjects were familiarized with a list of 60 congruous and incongruous sentences. During the second phase, ERPs were recorded as subjects silently read a set of 180 unconnected sentences. One third of the sentences were presented exactly as they had been seen in training (Old sentences), one third were presented for the first time (Completely New sentences), and one third involved a re-pairing of the frames and completions of the congruous and incongruous Old sentences (New Pair sentences). The N400 congruity effect was reduced for Old as compared with Completely New and New Pair sentence completions. These results suggest that N400 reflects processes that are sensitive to both existing semantic associations and representations of previous episodes that include the context of the eliciting stimulus. A late positive component (LPC) involving a sustained positive shift in the waveform after 600 ms was largest for incongruous completions and occurred somewhat earlier for Old sentences. This pattern of results is consistent with the notion that the LPC is an index of episodic retrieval and elaborative processes. The data also suggest the presence of an early onset slow positive shift that is only evident for New Pair congruous sentences.

Active and passive attention in schizophrenia: an ERP study of information processing in a linguistic task.

Attentional dysfunctions in schizophrenia were investigated using a sentence priming task. Schizophrenic patients and healthy control subjects were presented with sentences to which they were required to make a response based on either semantic or physical stimulus features. Schizophrenics' behavioural responses were slower than those of controls, particularly when attending to semantic relationships, but their performance was no less accurate. Both the P300 and the N400 components of the event-related potentials (ERPs) recorded to the sentence completions were attenuated in the schizophrenic sample. The results are interpreted in terms of a deficit in the active maintenance of semantic information in memory and the integration of new information with this representation.

The effect of repeated testing on ERP components during auditory selective attention.

The present study examined long-term repetition effects on human auditory event-related potentials (ERPs). ERPs were recorded from subjects performing the same multidimensional auditory selective attention task on six separate occasions spaced one week apart. The task required subjects to attend to tones that varied along the dimensions of location (L), pitch (P), and duration (D) and to detect prespecified target (L + P + D +) combinations of these attributes. Processing negativity (PN) between 100-400 ms did not change in amplitude or onset latency as a function of repeated experience with the task. In contrast, two measures of "very late" PN were reduced with practice. Specifically, the location effect measured over the 400-700-ms epoch was significant only for Weeks 1 and 2, and the separation of the L + P + D- ERP from other D- ERPs, measured over the 700-1000-ms epoch, was significantly reduced from Week 1 to Week 2. A late negative component (700-1000 ms) elicited by correctly identified targets increased between Weeks 1 and 2, consistent with subjects adopting the strategy of rehearsal of the target itself rather than the L + P + D- standard. P2 amplitude increased significantly for all standards, possibly due to decreased latency jitter in later weeks. N1 latency became significantly shorter over weeks, reflecting either increasing confidence in stimulus discrimination with repeated testing or the overlapping of an unchanging N1 with an increasing P2.

Diazepam-associated thrombophlebitis: a review and discussion of possible prevention.

Intravenous diazepam is an excellent anxiolytic drug for dental patients. Thrombophlebitis associated with its use has prompted this review. Recognition and management of thrombophlebitis are discussed along with the causes of vascular injury after intravenous diazepam. In two histologic studies, Graham and others thought it unlikely that precipitated crystals of diluted diazepam caused postinjection vasculopathology. It seems to be an inherent property of the vehicle or the drug itself. The reviewed methods of minimizing thrombophlebitis after intravenous diazepam are with hepari flush or saline solution flush, steroids, vein size and venipuncture site, the use of a different vehicle, dilutions, and the use of other benzodiazepines. Lorazepam, midazolam, and flunitrazepam are relatively new benzodiazepines that produce less thrombophlebitis than diazepam after injection. These newer benzodiazepines are still being investigated and more clinical trials must be done to recommend any of them as alternatives to intravenous diazepam in dentistry.