EEG correlates of the development of infant joint attention skills

The development of the capacity for social attention coordination, or "joint attention," is a major milestone of infancy. Data from a recent study of handicapped infants have raised the hypothesis that the tendency to initiate bids for joint attention may reflect processes associated with the frontal cortex to a greater extent than other forms of infant attention coordination (R. Caplan et al., 1993). This hypothesis was examined in a longitudinal study of 32 normally developing infants. The results indicated that EEG data at 14 months indicative of left frontal, as well as left and right central cortical activity, was associated with the tendency to initiate joint attention bids (IJA) at 14 and 18 months. In contrast, a pattern of left parietal activation and right parietal deactivation at 14 months was associated with the development of the capacity to respond to the joint attention bids (RJA) of others at 14 and 18 months. These results were interpreted to be consistent with a general anterior-posterior model of attention development (M. Posner & S. Petersen, 1990). The implications of these results for current conceptualizations of joint attention development, as well as for understanding the disturbance of joint attention skill development in autism are discussed.     

Phosphorylated KDR is expressed in the neoplastic and stromal elements of human renal tumours and shuttles from cell membrane to nucleus

Vascular endothelial growth factor (VEGF)-A is an important angiogenic factor in establishing the vasculature in renal cell carcinomas (RCCs). Since little is known about VEGF signalling in RCCs, the profile of phosphorylated KDR (pKDR) has been investigated and the intracellular location of the receptor has been examined in the present study. Using two monoclonal antibodies raised against the phosphorylated KDR epitopes (Y1059 and Y1214) known to mediate different VEGF functions, together with a commercial anti-KDR antibody and immunohistochemistry, the expression of pKDR was investigated in a series of normal (n = 25) and neoplastic kidneys (n = 54; clear cell n = 35; papillary n = 10; oncocytomas n = 8). pKDR was present in many tissue elements of both normal and neoplastic renal tissues, with strong expression in the cell membrane, cytoplasm, and nuclei of normal kidney and tumour cells, as well as endothelial cells in tumours of all histological types. Patterns and intensity were similar using both anti-pKDR antibodies. There was no significant correlation in clear cell carcinomas between pKDR expression and age (p = 0.57), tumour size (p = 0.2), gender (p = 0.59), grade (p = 0.2) or histological type (p = 0.36). To delineate further the intracellular processing that might account for the cellular distribution, confocal microscopy was also performed. Antibodies to the different phosphorylated epitopes demonstrated different intracellular staining patterns. This study shows that pKDR is present in a wide variety of renal tumours, suggesting that anti-VEGF therapy might have direct effects on tumour cells. It further suggests that cells traffic pKDR depending on the precise KDR tyrosines that are autophosphorylated in a manner that enables receptor activation to result in different functions.     

Initial evaluation of a continuous speech recognition program for radiology

The aims of this work were to measure the accuracy of one continuous speech recognition product and dependence on the speaker's gender and status as a native or nonnative English speaker, and evaluate the product's potential for routine use in transcribing radiology reports. IBM MedSpeak/Radiology software, version 1.1 was evaluated by 6 speakers. Two were nonnative English speakers, and 3 were men. Each speaker dictated a set of 12 reports. The reports included neurologic and body imaging examinations performed with 6 different modalities. The dictated and original report texts were compared, and error rates for overall, significant, and subtle significant errors were computed. Error rate dependence on modality, native English speaker status, and gender were evaluated by performing ttests. The overall error rate was 10.3 +/- 3.3%. No difference in accuracy between men and women was found; however, significant differences were seen for overall and significant errors when comparing native and nonnative English speakers (P = .009 and P = .008, respectively). The speech recognition software is approximately 90% accurate, and while practical implementation issues (rather than accuracy) currently limit routine use of this product throughout a radiology practice, application in niche areas such as the emergency room currently is being pursued. This methodology provides a convenient way to compare the initial accuracy of different speech recognition products, and changes in accuracy over time, in a detailed and sensitive manner.     

Laser induced thermal injury of rabbit cornea and treatment with anti-inflammatory agents

A moderately severe thermal injury of the central cornea of 48 Dutch-belted rabbit eyes was produced with a carbon (CO₂) laser. The lesions were photographed with a slit lamp (SL) camera immediately following the injury and at 1, 2, 4, 7, 14, 21, 30 and 60 days after the exposure. Lesion size, opaqueness, and depth were graded clinically by SL biomicroscopy at the same intervals. No significant differences were found (p 0.05) between groups of eyes treated with flurbiprofen (0.03%), prednisolone acetate (1%), and vehicle control four-times-a-day for three weeks following injury. Additionally, eyes were studied histopathologically at 3 and 60 days following injury by light and transmission electron microscopy, and clinically at 30 and 60 days by endothelial specular microscopy. Important clinical and histopathological findings included coagulative necrosis of the corneal epithelium, epithelial sloughing, fusion of stromal collagen, stromal edema and inflammatory cell infiltration, stromal scar formation, corneal thinning, endothelial hyperplasia and metaplasia, fibrinous anterior chamber reaction with hypopyon, and retrocorneal fibrous membrane formation.     

Direct membrane method for the study of interface-controlled transport of cholesterol in aqueous media

Studies were designed to demonstrate the use of a silicone rubber membrane diffusion cell in the mechanistic study of cholesterol mass transfer in aqueous media. The method is shown to be simple, precise, and well suited for delineating conditions which facilitate cholesterol transport. Traditional membrane diffusion resistance was determined with cholesterol solubilized in the nonionic surfactant, polyoxyethylene(10)-nonylphenol ether. The use of a charged surfactant additive, either sodium oleate or benzyldimethyltetradecylammonium chloride, reduced cholesterol membrane flux in a manner consistent with a transport barrier residing in the membrane and micelle interfacial regions. Quantitative determination of total transport resistance was good (CV of greater than 95%) for cases more than 99% interface controlled. Interfacial resistance imparted by the charged surfactant additive was essentially abolished by strong electrolyte (sodium chloride). Electrolyte was utilized in either the upstream or the downstream aqueous compartment to enhance cholesterol transport by a mechanism which is consistent with a marked increase in the frequency of micelle collision with the corresponding membrane surface. When the downstream interfacial component of total transport resistance was "short circuited" by electrolyte in sequential transport runs using the same membrane, a "dumping" of cholesterol by the membrane compartment was observed. Limited studies with a second nonionic surfactant, polyoxyethylene(15)-tridecyl ether, suggest that the structure of separate micelle components may also be related to cholesterol mass transfer which occurs via a micelle collision in the interfacial region.     

Standardized mean regional method for calculating global positron emission tomographic measurements

A new "mean regional" method for calculating global hemispheric values of blood flow, blood volume, and metabolism with positron emission tomography is presented. It is based on a standardized set of regions defined according to coordinates in a stereotactic atlas of the brain. Region locations in each individual scan were determined by a localization technique that is independent of the appearance of the physiological images. Measurements obtained with this mean regional method minimize contributions from nonbrain structures such as ventricles or venous sinuses and provide the necessary basis for comparisons among different subjects and laboratories.