Ultrastructural characterizations of olfactory pathway neurons in layer II of the entorhinal cortex in monkey.

The somatic size, shape, dendritic and axonal morphology, and synaptology of representative neurons in layer II of the primate entorhinal cortex (EC) were analyzed. Layer II "islands" contained large spinous multipolar cells with triangular somata and local circuit axons in addition to multipolar neurons with large, radially arrayed, aspinous, primary processes and thick tapering axons. Small pyramidal neurons with a single, spinous, apical primary segment that bifurcated a short distance from the somata were also found in layer II. Subsequent spinous segments of these neurons with long terminal segments exhibited a paucity of branching in addition to having thick axons tapering into subjacent layers. The importance of providing these additional axonal, dendritic, and synaptic characterizations lies in the contextual role these neurons play in the connectional patterns of the EC with regard to olfaction, olfactory memory, and pathological variations.

Temporal bone fractures.

The diagnosis and monitoring of patients presenting to an emergency department with blunt temporal bone fracture and complications requiring acute management were reviewed for a four-month period. Of 104 trauma patients with closed head injury, 15 patients were diagnosed with temporal bone fracture, 12 of whom survived their injuries. Four patients developed cerebrospinal fluid (CSF) otorrhea and two patients developed facial nerve paralysis; all patients had resolution of complications with conservative management. Significant shortcomings in the initial evaluation and monitoring of patients with temporal bone fracture were identified. Specific and thorough facial nerve examinations were not initially conducted on temporal bone fracture patients and subsequent inpatient monitoring for facial nerve paralysis and CSF otorrhea was incomplete. The outcome of temporal bone fracture is discussed. This article reminds the emergency physician of the importance of initial diagnosis and documentation of temporal bone fractures.

Maxillary sinusitis in the surgical intensive care unit: a study using bedside sinus ultrasound.

PURPOSE: This study investigates the incidence of acute maxillary sinusitis (AMS) in the surgical intensive care unit (SICU). METHODS: One hundred consecutive patients admitted to the SICU were examined in a prospective observational mode. Bedside sinus ultrasound (SUS) was performed on admission and every 48 hours. Patients with sinus fluid by SUS and unexplained sepsis underwent confirmatory sinus aspiration. RESULTS: The development of fluid in the maxillary sinus was identified in 15 patients by SUS. Acute maxillary sinus occurred in only 1 (1%). CONCLUSION: This study shows SUS to be a simple, efficient method for determining the presence of maxillary sinus fluid in the SICU. Acute maxillary sinus was an unusual finding. Our policy of avoidance of nasal instrumentation may have contributed to the low incidence of AMS in this high-risk patient population.

Neurons of the lateral entorhinal cortex of the rhesus monkey: a Golgi, histochemical, and immunocytochemical characterization.

This study identifies the neuronal types of the rhesus monkey lateral entorhinal cortex (LEC) and discusses the importance of these data in the context of the connectional patterns of the LEC and the possible role of these cells in neurodegenerative diseases. These neuronal types were characterized with the aid of Golgi impregnation techniques. These characterizations were based upon their spine densities, dendritic arrays, and, where possible, axonal arborizations. The cells could be segregated into only spinous and sparsely spinous types. The most numerous spinous types were pyramidal neurons. Other spinous types included multipolar, vertical bipolar and bitufted, and vertical tripolar neurons. The sparsely spinous neuronal types consisted of multipolar, horizontal bipolar and bitufted, and neurogliaform cells. These cells were further classified with the aid of histochemical stains and immunocytochemical markers. Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry stained multipolar, bipolar, and bitufted neurons. Stain for cytochrome oxidase (CO) was found in pyramidal and nonpyramidal cell types. Immunocytochemical techniques revealed several nonpyramidal neurons that contain somatostatin (Som) or substance P (SP). This study complements previous analyses of the neuronal components described in the LEC and adds further information about the distribution of selected neurochemicals within this cortex.

Silicone tracheal cannula. Update.

The Montgomery silicone tracheal cannula is a current alternative to the standard tracheotomy tube. This paper extends the 1986 report to include unusual indications for its use, complications and their management, and further recommendations on its use gathered from recent experience.

Improved case finding for pediatric hearing loss: cost analysis of school screening programs.

The majority of school hearing conservation programs employ pure tone identification audiometry as a basis of referral for further evaluation. An analysis of the cost impact of school screening programs is presented and a method of relating costs to screening program accuracy is described. This type of analysis may be used as a model for estimating cost impact and cost-benefit for pure tone audiometry and other techniques of screening for hearing loss.