Interinstitutional comparison of frozen section consultations. A college of American Pathologists Q-Probes study of 90,538 cases in 461 institutions

OBJECTIVE: To assess concordant, discordant, and deferred diagnosis rates from frozen sections; to determine reasons for discordance; to identify pathologic processes associated with discordant diagnoses; to determine false-positive or false-negative rates for neoplasms; and to identify anatomic sites associated with discordant frozen section diagnoses. DESIGN: Q-Probes study of the College of American Pathologists. PARTICIPANTS: Four hundred sixty-one institutions participating in the Q-Probes program from November 1, 1990, through March 31, 1991. MAIN OUTCOME MEASURES: Concordant and discordant diagnosis rates. RESULTS: The frozen section concordance rate for diagnoses from the aggregate group was 98.58% and the discordance rate was 1.42%, when uncorrected for deferred diagnoses. During the study period, participating institutions accessioned 1,693,331 surgical pathology cases; 90,538 of these cases were evaluated by frozen section consultation, resulting in the examination of 121,668 specimens and 148,506 frozen section blocks. The majority of the frozen section discordances occurred because of misinterpretation of the original frozen section (31.8%), presence of diagnostic tissue in permanent sections of the frozen block when the frozen section was negative (30.0%), and presence of diagnostic tissue in the portion of the specimen not sampled by the frozen section (31.4%). Of the discordant diagnoses, 67.8% had false-negative diagnoses for neoplasm. The pathology processes and anatomic sites represented in discordant diagnoses are also evaluated. CONCLUSIONS: High diagnostic accuracy of frozen section consultations was demonstrated. Frozen sections are used to evaluate a variety of pathologic processes and anatomic sites.     

Electrical activity in rat tail artery during asynchronous activation of postganglionic nerve terminals by ciguatoxin-1

1. The effects of ciguatoxin-1 (CTX-1) on the membrane potential of smooth muscle cells have been examined in rat proximal tail arteries isolated in vitro. 2. CTX-1 (> or = 10 pM) increased the frequency of spontaneous excitatory junction potentials (s.e.j.ps). At 100-400 pM, there was also a marked and maintained depolarization (19.7 +/- 1.4 mV, n = 14, at 400 pM). 3. In 20-400 pM CTX-1, perivascular stimuli evoked excitatory junction potentials (e.j.ps) which were prolonged in time course relative to control. 4. Although threshold and latency of the e.j.p. were not affected by CTX-1 (< or = 400 pM), propagated impulses were blocked at > or = 100 pM. 5. The spontaneous activity and the depolarization produced by CTX-1 were reduced in the presence of Ca2+ (0.1 mM)/Mg2+ (25 mM), omega-conotoxin (0.1 microM) or Cd2+ (50-100 microM). 6. All effects of CTX-1 were abolished by tetrodotoxin (0.3 microM). 7. Raised Ca2+ (6 mM) reduced the depolarization and spontaneous activity produced by CTX-1. 8. In 400 pM CTX-1, the membrane repolarized (17 +/- 3.2 mV, n = 4) following the addition of phentolamine (1 microM). S.e.j.ps and e.j.ps were selectively abolished by suramin (1 mM), and the membrane repolarized by 1.3 +/- 1.6 mV (n = 4). 9. We conclude that CTX-1 releases noradrenaline and ATP by initiating asynchronous discharge of postganglionic perivascular axons. In 100-400 pM CTX-1, the smooth muscle was depolarized to levels resembling those recorded in this artery during ongoing vasoconstrictor discharge in vivo.     

Ectasia of the vertebral artery as a cause of isolated pyramidal tract signs: case report and a review of the literature

A rare presentation of vertebral artery ectasia is reported with magnetic resonance imaging and angiographic correlation. The unusually low level of the abnormality had previously resulted in an incorrect diagnosis of primary pyramidal degeneration. One similar case has been reported in the world literature.     

Pronoun resolution without pronouns: some consequences of memory-based text processing

A memory-based processing approach to discourse comprehension emphasizes the rapid deployment of information in memory to facilitate understanding of the text that is currently being read. S. B. Greene, R. J. Gerrig, G. McKoon, and R. Ratcliff (1994) demonstrated that when a text described the reunion of 2 characters who had previously discussed a 3rd character, the accessibility of the 3rd character increased, and the use of an unheralded pronoun (R. J. Gerrig, 1986) to refer to that character was felicitous. In experiments in this article, the authors demonstrate that concepts related to the unheralded pronoun also increase in accessibility and that those concepts form associations in memory with concepts present in the discourse at the time the pronoun is used. The authors also show that the increase in accessibility for the referent of the pronoun, as well as the appropriate long-term memory associations, occurs even in the absence of the pronoun.     

Extended cervical mediastinoscopy

Organic solvent inhalation is a serious problem among youths in Japan. It induces physical and mental disorders, and is related closely to crime and delinquency. The relationship between solvent inhalation and antisocial behavior was investigated in 75 youths. The subjects were divided into three groups according to the level of violent behavior and the time of appearance: a non-violent group, a late-onset group (violence occurred after the start of inhalation) and an early-onset group (violence had occurred before the start of inhalation). Various parameters were compared among the groups. The late-onset group showed the following characteristics; (i) the frequency of inhalation was high, and many subjects experienced hallucinations and mood changes caused by inhalation; (ii) the family environment was characterized by conflict; and (iii) the subjects had strong psychological conflicts and showed dissociative coping with frustration. The violence, psychological conflict and dissociation in this group were found to be related to the inhalation, with familial conflict as a background. The violence in the early-onset group was considered to be the manifestation of a violent personality as the frequency of inhalation and the incidence of mental symptoms were both low. The subjects in this group showed weak psychological conflict and tended to be demanding of others when attempting to cope with frustration. Two types of violent behaviors in the teenagers who inhaled solvents were identified. The violence of solvent inhalers should be managed according to the type.