Physiology of the young adult Fischer 344 rat inferior colliculus: responses to contralateral monaural stimuli

This study was designed to establish the young adult (3 month) Fischer 344 (F344) rat as a model of inferior colliculus (IC) physiology, providing a baseline for analysis of changes in single unit responses as the animals age and for the study of noise induced hearing loss. The response properties of units localized to the central nucleus of the IC (CIC) and those localized to the external cortex of the IC (ECIC) were compared in order to better characterize differences between these two subnuclei in the processing of simple auditory stimuli. In vivo extracellular single unit recordings were made from IC neurons in ketamine/xylazine anesthetized young adult F344 rats. When a unit was electrically isolated, the spontaneous activity level, characteristic frequency (CF) and CF threshold were determined. Rate/intensity functions (RIFs) in response to contralateral CF tones and to contralateral noise bursts were obtained as were tone isointensity functions. The recording site was marked by ejecting horseradish peroxidase (HRP) from an electrode. Locations of recorded units were determined from electrode track marks and HRP marks in serial brain sections. Recordings were made from 320 neurons in the IC; 176 were localized to the CIC and 87 to the ECIC. Thirteen percent of the units in each subdivision were found to be poorly responsive to auditory stimulation (clicks, tones or noise), and spontaneous activity was generally low. Characteristic frequencies representative of the full rat audiogram were found in each subdivision with the mean threshold significantly higher in the ECIC (28.7 dB SPL) than in the CIC (22.3 dB SPL). The mean maximum discharge rate to CF tone bursts was near 24 spikes/s in each subdivision. Dynamic range tended to be higher in the ECIC (28.3 dB) than in the CIC (23.2 dB), reflecting the lower percentage of nonmonotonic units found in the ECIC. Most units responded more robustly with a slower tone presentation rate, displayed lower levels of discharge to noise bursts than to tone bursts, and had differently shaped tone and noise RIFs. Most units were classified as onset responders to CF tone bursts in both subdivisions, with the percentage of onset responders higher in the ECIC (68.9%) than in the CIC (57.8%). First spike latency did not differ significantly between the subdivisions, but tended to be shorter in the CIC. The breadth of the excitatory receptive fields did not differ significantly between subdivisions, although the mean was slightly larger in the ECIC. These results are generally consistent with the results of CIC studies from other species, establishing the F344 rat as a model of CIC physiology. Differences between CIC and ECIC units included a higher percentage of nonmonotonic RIFs and lower percentage of onset temporal response patterns in the CIC than in the ECIC. Some properties which have been previously used as hallmarks for differentiation between CIC and ECIC units, namely broader tuning and longer first spike latencies in the ECIC, did not reach statistical significance in this study. These may reflect species differences and/or the highly variable and largely overlapping sets of responses evident in the large sample size used in this study.     

The int genes of bacteriophages P22 and lambda are regulated by different mechanisms

Bacteriophage P22 and lambda are related bacteriophages with similar gene organizations. In lambda the cll-dependent Pl promoter is responsible for lambda int gene expression. The only apparent counterpart to pl in P22 is oriented in the opposite direction, and cannot transcribe the P22 int gene. We show that this promoter, called P(al), is active both in vivo and in vitro, and is dependent upon the P22 cll-like gene, called c1. We have also determined the DNA sequence of a 3.3 kb segment that closes the gap between previously reported sequences to give a continuous sequence between the P22 pL promoter and the int gene. The newly determined sequence is densely packed with genes from the pL direction, and the proteins predicted by the sequence show excellent correlation with the proteins mapped by Youderian and Susskind in 1980. However, the sequence contains no apparent genes in the opposite (p(al)) direction, and no additional binding motifs for the P22 c1 protein. We conclude that int gene expression in P22 is regulated by a different mechanism than in lambda.     

The effect of alcohol ingestion on exhaled nitric oxide

The concentration of nitric oxide (NO) is increased in the exhaled air of patients with inflammatory lung diseases, including asthma, possibly reflecting cytokine-mediated chronic airway inflammation. Endogenous NO is generated from L-arginine by the action of several types of NO synthase (NOS). NOS have structural similarities with cytochrome P450 reductases. Alcohol decreases exhaled NO in animals, but this has not previously been investigated in man. We studied the effect of alcohol ingestion in nine asthmatic and 12 normal subjects, measuring the peak concentration of exhaled NO using a modified chemiluminescence analyser. A significant decrement in NO occurred in asthmatic patients (mean +/- SEM before ethanol 204 +/- 58 to 158 +/- 59 parts per billion (ppb) after ethanol; p < 0.02), without significant change in the normal subjects (122 +/- 14 to 114 +/- 15 ppb). Thus, in our study, alcohol decreased exhaled nitric oxide in asthmatic subjects but not in normal individuals. This may reflect preferential action on inducible nitric oxide synthase which is expressed in asthmatic airways. An inhibitory effect of ethanol on inducible nitric oxide synthase may contribute towards the effect of alcohol in asthma.     

A national survey on seclusion and restraint in state psychiatric hospitals

OBJECTIVES: State psychiatric hospitals across the U.S. were surveyed to develop national normative data on the incidence of seclusion and restrain and of injuries to patients and staff resulting from aggression by patients. METHODS: A survey instrument was sent to 225 state hospitals requesting information for a one-year period on the number of patients placed in seclusion or restraint, the number of discrete incidents of seclusion and restraint, the number of hours patients spent in seclusion or restraint, and the number of injuries to patients and staff attributable to aggression by patients. Rates of seclusion, restraint, and injuries were calculated to control for variation in hospital censuses. Percentile ranks for the various rates were calculated to allow hospitals to compare their rates. RESULTS AND CONCLUSIONS: A total of 101 state hospitals in 44 states and the District of Columbia returned the survey. In general, smaller hospitals had higher rates of seclusion and restraint. However, large standard deviations in the mean rates suggested considerable variability between hospitals in the sample. Small positive correlations between rates of seclusion and rates of restraint suggested that the hospitals did not use of the two interventions exclusively.     

Community health worker competency in managing acute respiratory infections of childhood in Bolivia

A competency-based training and evaluation method was developed to improve and assess the management of acute respiratory infections (ARI) in young children by community health workers (CHWs) in Bolivia. This method was used to evaluate three groups of Bolivian CHWs, provide them with a one-day refresher course in ARI management, and assess the effects of the course. The results showed the CHWs capable of acquiring the skills needed to effectively manage ARI cases in accordance with the World Health Organization's ARI case management strategy. It was found important, however, that their training emphasize how to count the respirations of children with tachypnea and how to identify chest indrawing. In general, the competency-based methods appeared to be effective in training and evaluating CHWs in the area of ARI case management; it is expected that these methods will prove useful in other community-based health interventions.     

One-stage curative treatment of neoplastic colonic obstruction: long-term results, comparison with elective surgery and therapeutic implications

Over a period of ten years (1980-1989) 528 patients with colon cancer were treated at one institution. One hundred seventy nine (33.9%) were obstructed (O) and underwent emergency surgery, while 349 received elective (E) treatment; of these 363 had one-stage curative treatment. Operative mortality was 10.3% (O) and 3.5% (E) respectively (p < .0.5). Three hundred forty three patients survived surgery and entered follow-up: 96 were O (M:F, 54:42) and 247 E (M:F, 119:128, p = N.S.). Their mean age was 69.5 and 64.4 (p < .001), respectively. Dukes' stage and histological grading were evenly distributed within the two groups, but sites of the primary were not (p < .001). During the follow-up local recurrence occurred in 40 patients (13 O, 27 E, p = N.S.) and metastatic disease in 78 (28 O, 50 E, p < .05, Life Table Analysis) including liver recurrence in 17 O and 30 E (p = .063). Five year crude survival (51%) was significantly worse in obstructed patients. Multivariate analysis showed that Dukes' stage and obstruction were the only prognostic factors of recurrent disease, while survival was affected by the same variables and age over 70. When recurrent disease was introduced in the model survival depended on Dukes' stage, site of the primary and age over 70 and the variable obstruction disappeared as prognostic factor. Right sided tumours showed a better and those at the splenic flexure a worse prognosis. Despite one-stage curative treatment obstruction carries a significantly higher risk of developing metastatic disease, suggesting that obstruction enhances cancer cell dissemination. These patients might benefit from per-operative intra-portal and post-operative systemic adjuvant chemotherapy.     

Use of tissue expanders in final reconstruction of infrapubic midline scar, mons pubis, and vulva after bladder exstrophy repair

Two patients following bladder exstrophy repair presented for final cosmetic reconstruction with the characteristic lower abdominal midline scar, bisected mons pubis, and laterally displaced labia majora. Tissue expanders were used to obtain additional skin and subcutaneous tissue. After adequate serial expansion, the expanders were removed, scar tissue excised, and primary approximation of healthy tissues performed. A tension-free closure and esthetically pleasing midline incision, mons pubis, and vulva were obtained.