Neuropsychological deficit in schizophrenic subtypes: paranoid, nonparanoid, and schizoaffective subgroups

Schizophrenic patients were carefully diagnosed and screened for a history of neurological disorders. Diagnosis and subtyping was based on DSM-III-R criteria, using the Structured Clinical Interview for DSM-III-R, which was administered by trained interviewers and confirmed by a research psychiatrist. The schizophrenic patients were compared with an age-matched control group on an extensive battery of neuropsychological measures. The undifferentiated/disorganized schizophrenic patients were consistently the most impaired on a broad range of tasks. When the effect of symptom severity and drug level were statistically controlled (analysis of covariance), however, the magnitude and number of differences were substantially reduced. The perseverative error score from the Wisconsin Card Sort Test showed the greatest difference between the groups. However, the strongest and most consistent effects were observed in relation to symptom ratings. These data indicate the importance of controlling for medication and symptom severity, and suggest that current diagnostic classifications may not be the most useful factors for studies of the cognitive correlates of schizophrenia.     

Intraventricular injection of NGF, but not BDNF, induces rapid motor activation that is inhibited by nicotinic receptor antagonists

 The acute and subacute effects of intracerebroventricularly (ICV) administered nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF) on locomotor activity were evaluated in awake adult rats. Immediately after ICV injection through an implanted cannula, locomotor activity was measured by a computerized system using infrared photocells, which allowed us to record locomotion, motility, and rearing simultaneously. A single dose of 5 μg mouse β-NGF produced significant increases in horizontal ambulatory components of locomotor activity (locomotion and motility), but not vertical movement (rearing) 30–45 min after ICV administration. These increases lasted for at least 3–4 h. Systemic injection of 2.0 mg/kg mecamylamine, a central nicotinic receptor antagonist, inhibited the hyperactivity induced by NGF. Systemic injection of 0.5 mg/kg scopolamine, a muscarinic receptor antagonist, did not interfere with the NGF effects. Thus, while scopolamine induced marked increases in all three measures of behavior in both NGF and cytochrome-c-treated animals, locomotion and motility remained significantly higher in the NGF group. Immunohistochemistry demonstrated that NGF diffused readily from the ventricular space into brain parenchyma on the injected side and could be visualized 1 h after ICV injection. These results suggest that ICV administration of NGF increases locomotor activity by inducing acetylcholine release, and that nicotinic receptors are involved in the hyperactivity induced by NGF. ICV administration of 5 μg recombinant human BDNF had no significant effect on locomotor activity during the 0- to 4-h period after ICV injection. However, it produced significant decreases in locomotion, motility, and rearing 24–26 h later. Hence ICV administration of BDNF has entirely different effects on animal behavior from those evoked by NGF. While NGF elicits increases in ambulatory behavior within hours, BDNF causes delayed decreases in ambulatory behavior. Received: 21 October 1996 / Accepted: 20 March 1997     

Actinomycosis of the retroperitoneum and an extremity: CT features

A patient presenting with thigh and flank masses and back pain for 3 months proved to have actinomycosis involving the retroperitoneum and quadriceps muscle. Retroperitoneal involvement without intraperitoneal disease is rare. Computed tomography (CT), however, showed disease transgressing adjacent anatomic compartments with direct extension through the body wall and involvement of adjacent bony structures which is characteristic of actinomycosis.     

Pressure Ulcer Prevalence and Incidence in a Rehabilitation Hospital

Pressure ulcers remain a serious health problem, especially in terms of personal suffering and economics. The study described here, conducted in a rehabilitation setting, investigated the prevalence (number of persons with pressure ulcers at a given time) and the incidence (number of persons developing pressure ulcers over a given time) of pressure ulcers. Skin assessments and risk assessments of the subjects were completed using the Braden Scale for Predicting Pressure Sore Risk. Demographic data were obtained. The prevalence rate was 25%, although there was no incidence during the time of this study. Factors associated with the prevalence of pressure ulcers are discussed.     

High-resolution EEG mapping of cortical activation related to working memory: effects of task difficulty, type of processing, and practice

Changes in cortical activity during working memory tasks were examined with electroencephalograms (EEGs) sampled from 115 channels and spatially sharpened with magnetic resonance imaging (MRI)-based finite element deblurring. Eight subjects performed tasks requiring comparison of each stimulus to a preceding one on verbal or spatial attributes. A frontal midline theta rhythm increased in magnitude with increased memory load. Dipole models localized this signal to the region of the anterior cingulate cortex. A slow (low-frequency), parietocentral, alpha signal decreased with increased working memory load. These signals were insensitive to the type of stimulus attribute being processed. A faster (higher-frequency), occipitoparietal, alpha signal was relatively attenuated in the spatial version of the task, especially over the posterior right hemisphere. Theta and alpha signals increased, and overt performance improved, after practice on the tasks. Increases in theta with both increased task difficulty and with practice suggests that focusing attention required more effort after an extended test session. Decreased alpha in the difficult tasks indicates that this signal is inversely related to the amount of cortical resources allocated to task performance. Practice-related increases in alpha suggest that fewer cortical resources are required after skill development. These results serve: (i) to dissociate the effects of task difficulty and practice; (ii) to differentiate the involvement of posterior cortex in spatial versus verbal tasks; (iii) to localize frontal midline theta to the anteromedial cortex; and (iv) to demonstrate the feasibility of using anatomical MRIs to remove the blurring effect of the skull and scalp from the ongoing EEG. The results are discussed with respect to those obtained in a prior study of transient evoked potentials during working memory.      

MR imaging of the female pelvic region.

Magnetic resonance (MR) imaging is a valuable technique for noninvasive evaluation of the female pelvic region. This article presents the normal anatomy and abnormalities of the female pelvis. MR imaging may be more useful than clinical evaluation or other imaging modalities in diagnosing or staging developmental anomalies, leiomyomas, adenomyosis, endometrial or cervical carcinoma, vaginal neoplasms, ovarian cysts, endometriosis, teratomas, polycystic ovaries, or other ovarian masses. It could potentially replace laparoscopy as a more useful tool in the diagnosis of uterine anomalies. MR imaging is generally capable of helping determine whether a pelvic mass is uterine or adnexal in origin and may be used to characterize some adnexal masses. In some cases, MR imaging is used to differentiate recurrent disease from posttreatment fibrosis, which aids in treatment planning.     

An investigation of the sites of mitotic activity in the guinea-pig thymus using autoradiography and Colcemid-induced mitotic arrest

Tritiated thymidine autoradiographs prepared from sections of guinea-pig thymus were compared with sections from animals treated with the mitotic arresting drug Colcemid. Autoradiography demonstrated the existence of two synthesizing zones, the previously described subcapsular cortex and a new zone of activity, the corticomedullary junction. The existence of these zones was confirmed quantitatively in the Colcemid-treated animals.     

Coexposure to toluene and p-xylene in man: central nervous functions.

Sixteen men were studied in an exposure chamber to assess the effect of four hours' exposure to toluene (3.25 mmol/m3), xylene (2.84 mmol/m3), a mixture of toluene and xylene (2.20 + 0.94 mmol/m3), and a control condition. With the aid of microcomputers, subjects performed tests of simple reaction time, short term memory, and choice reaction time immediately after entering the chamber, after two, and after four hours' exposure. The results indicate that the performance on the tests was unaffected by exposure. In the light of this result the risk of an acute effect on central nervous functions after exposure for four hours at concentrations that do not exceed the Swedish threshold limit values was considered to be minimal.