An Inbred Epilepsy-Prone Substrain of BALB/c Mice Shows Absence of the Corpus Callosum, an Abnormal Projection to the Basal Forebrain, and Bilateral Projections to the Thalamus

BALB/c mice lack a corpus callosum in about 11% of the population.Two inbred substrains of BALB/c mice, epilepsy-prone (EP) andepilepsy-resistant (ER), have been examined to determine whetherthese substrains differ in regard to corpus callosum morphology.Further, this study addressed the issue of whether misroutedcortical axons form an aberrant pathway instead of the corpuscallosum. Initial studies that examined fresh brain tissue ofadult animals revealed normal corpora callosa in all ER micebut deficient or absent corpora callosa in all EP mice. Subsequently,Dil crystals were placed in the motor cortices of aldehyde-fixedbrains of 2-week-old animals to investigate cortical projectionsin both inbred substrains of mice. Fluorescent microscopy revealedthat all of the ER animals had normal corpora callosa, whereasall EP animals exhibited either reduced corpora callosa (partiallycallosal) or an absence (acallosal) of this structure. Bothacallosal and partially callosal EP mice displayed an extensive,aberrant projection to the basal forebrain as well as bilateralprojections to midline and intralaminar thalamic nuclei. Thefibers projecting to the basal forebrain arose from the cortex,coursed toward the midline before turning ventrally along themidline, and appeared to terminate in the medial septal nucleusand the nucleus of the diagonal band. ER animals lacked thisaberrant cortical projection to the basal forebrain. Electronmicroscopic results obtained from EP mice indicated that labeledaxons in this aberrant pathway formed axosomatic, axodendritic,and axospinous synapses with the neurons in the medial septal/diagonalband complex. The function of the aberrant projection to thebasal forebrain remains unknown but it may provide an abnormalexcitatory input to a region that provides cholinergic and GABAergicinput to the cerebral cortex and hippocampus. The additionalprojections to midline and contralateral intralaminar thalamicnuclei in EP mice may function to intensify the synchronizationof bilateral discharges.     

Evaluation of the Transverse Sinus by Magnetic Resonance Venography: Limitations-An Illustrative Case Report

Many techniques of magnetic resonance angiography depend on flow velocity. The broad normal range of venous flow velocities and preferential patterns of drainage, particularly in the transverse sinuses, may produce images that are diagnostically misleading. This reports such a case, with samples of various flow patterns in the transverse sinuses of other individuals, as demonstrated by one magnetic resonance angiographic technique (time-of-flight).     

Severe odontogenic infections, part 2: prospective outcomes study.

PURPOSE: The purpose of this study was to identify significant predictors of 4 outcomes in patients with severe odontogenic infections: abscess formation, penicillin therapeutic failure (PTF), length of hospital stay (LOS), and need for reoperation. PATIENTS AND METHODS: We used a prospective case series study design and enrolled 37 consecutive patients admitted for severe odontogenic infection between March 1996 and June 1999. Treatment consisted of intravenous penicillin (PCN) or clindamycin in PCN-allergic patients, surgical incision and drainage, and extraction(s) as soon as possible. Study variables were categorized as demographic, preadmission, time-related, preoperative, anatomic, treatment, microbiologic, and complications. The primary outcome variables were abscess formation, PTF, LOS, and reoperation. Multivariate linear and logistic regression techniques were used to measure associations between study variables and the outcome variables. RESULTS: The sample consisted of 37 subjects (23 male, 14 female) with a mean age of 34.9 +/- 15.8 years. Multivariate analyses, controlling for confounding variables, indicated that culture of Peptostreptococci was a negative predictor of abscess formation. LOS was predicted by the number of infected spaces and duration of operation. There was no significant predictor of PTF or reoperation on multivariate analysis, although PCN-resistant organisms were isolated in all cases of PTF. CONCLUSION: Increased LOS in severe odontogenic infections is predicted by the anatomic extent and severity of the infection and the occurrence of complications such as PTF and the need for reoperation. PTF is significantly associated with later identification of PCN-resistant organisms. The role of Peptostreptococci in abscess formation warrants further investigation.     

Family Nursing Research, Theory and Practice

The absence of critical dialogue regarding what constitutes family nursing prevents the further development of the specialty area of family nursing. In this essay, the author issues nine challenges faced by those who would contribute to the development of family nursing.     

Quality of life and Kaposi sarcoma: using preference techniques to value the health gains from treatment

The goal of this work was to investigate preference techniques to value potential health gains from treatments of Kaposi sarcoma (KS). The study was designed to take the form of face-to-face interviews with a sample of men with a history of HIV/AIDS ( n=15) or HIV/AIDS and KS ( n=17). The main outcome measure was quality of life (QoL) associated with various KS disease states expressed on a scale from 0 (death) to 1 (perfect health), obtained though time trade-off (TTO) and rating scale techniques. For cutaneous lesions only, the mean TTO preference score value was 0.27. In other words, the men were willing to trade a life expectancy of 5 years for a shorter period (1.4 years) in perfect health. More severe KS health states were rated lower (0.07-0.09). The mean rating scale value for cutaneous lesions only was 0.11 and ranged from -0.10 to -0.04 for the more severe conditions; these values were systematically lower than the TTO ( P=0.014). A large overall potential gain in QoL from treatment (partial response minus stable disease) was found for each condition to be reflected in both the TTO (from 0.31 to 0.55) and the rating scale (from 0.38 to 0.44). Respondents associate KS health states with extremely poor QoL and indicate that large gains are possible through modest treatment effects. While TTO returns higher values than the rating scale, potential gains from treatments were similar. The techniques appear to be suitable for application to QoL and economic evaluation of treatments of KS.     

Nerve biopsy findings in different patterns of proximal diabetic neuropathy

Besides distal symmetrical sensory polyneuropathy (DSSP), middle-aged diabetic patients may present with focal or multifocal neuropathies, including proximal neuropathy of the lower limbs, the pathophysiological features of which are uncertain. We studied 10 non–insulin-dependent diabetic patients, 45 to 72 years of age, who developed a painful proximal neuropathy of the lower limbs for which other causes of neuropathy were carefully excluded. The proximal neuropathy was asymmetrical in all patients, sensory in 4, motor and sensory in the others. Signs of DSSP were present in all. A sample of the intermediate cutaneous nerve of the thigh, a sensory branch of the femoral nerve, was taken by biopsy and examined by light and electron microscopy. Examination of the nerve specimens revealed ischemic nerve lesions in 3 patients. Nerve ischemia was associated with vasculitis and inflammatory infiltration in 2 of them. In the other patients the lesions of the cutaneous nerve of the thigh included a varying incidence of axonal and demyelinative lesions similar to those observed in DSSP, with mild inflammatory infiltration in 4 of them. The density of myelinated and of unmyelinated was variably decreased. This study shows that axonal and demyelinative lesions similar to those found in diabetic DSSP are present in proximal nerves in mild forms of proximal diabetic neuropathy; while nerve ischemia, inflammatory infiltration, and vasculitis are encountered in the most severe forms of proximal diabetic neuropathy.     

Differences in triage thresholds for patients presenting with possible acute coronary syndromes: more than meets the eye.

BACKGROUND: Many studies have shown differences in cardiac care by racial/ethnic groups without accounting for institutional factors at the location of care. OBJECTIVE: Exploratory analysis of the effect of hospital funding status (public vs private) on emergency department (ED) triage decision making for patients with symptoms suggestive of acute coronary syndromes (ACSs) and on the likelihood of ED discharge for patients with confirmed ACS. STUDY DESIGN AND SETTING: Secondary analysis of data from a randomized controlled trial of 10,659 ED patients with possible ACS in five urban academic public and five private hospitals. The main outcome measures were the sensitivity and specificity of hospital admission for the presence of ACS at public and private hospitals and the adjusted odds of a patient with ACS not being hospitalized at public versus private hospitals. RESULTS: Of 10,659 ED patients, 1,856 had confirmed ACS. For patients with suspected ACS, triage decisions at private hospitals were considerably more sensitive (99 vs 96%; p<.001) but less specific (30 vs 48%; p<.001) than at public hospitals. The difference between hospital types persisted after adjustment for multiple patient-level and hospital-level characteristics. CONCLUSION: Significant differences in triage for patients with suspected ACS exist between public and private hospital EDs, even after adjustment for multiple patient demographic, clinical, and institutional factors. Further studies are needed to clarify the causes of the differences.