Genetic analysis of ozone-induced acute lung injury in sensitive and resistant strains of mice

Sprague-Dawley rats sedated with intraperitoneal injection of diazepam (7.5 mg/kg) were placed in a plethysmograph to measure the changes in spontaneous respiration. Inhalation of methacholine (MCh) or acetylcholine (ACh) aerosol did not alter the volume of breathing, but increased respiratory frequency (RF) to the same extent in a concentration-dependent manner. On the other hand, the tachypnea effect of MCh lasted 11 min, and that of ACh only 3 min. Urethane anesthesia inhibited spontaneous respiration and the response to MCh. Atropine, salbutamol and aminophylline inhibited MCh-induced tachypnea. In sensitized rats, the response to MCh was potentiated 6 h after inhalation of ovalbumin aerosol. The results indicate that sedation with diazepam and inhalation of MCh aerosol used in this report are suitable for measuring airway responsiveness in terms of degree of increase of respiratory frequency.     

The detection of ductal carcinoma in situ at mammographic screening enables the diagnosis of small, grade 3 invasive tumours

This study was carried out to assess the frequency of ductal carcinoma in situ (DCIS) occurring within and surrounding grade 3 invasive tumours and the effect of its detection on size and nodal stage of invasive carcinomas at mammographic detection. Grade 3 tumours with either no associated DCIS or DCIS only within the invasive component were significantly larger in size than tumours with surrounding DCIS (P < 0.02) and were less likely to be under or equal to 10 mm in size (0% or 13% vs 30% respectively, P < 0.02). Tumours with mammographic calcification were more likely to be less than or equal to 10 mm in size than non-calcific tumours (32% vs 11% respectively, P < 0.05). This was because of the high frequency of tumours less than or equal to 10 mm in size in the linear/branching calcification group. Tumours showing calcification without a mass also appear to be a group with good prognostic features, with a mean size of 13 mm, 33% being 10 mm or less in size and only 17% being node positive. We have found that the presence of surrounding DCIS enables earlier detection of grade 3 invasive carcinomas because of the presence of mammographically visible calcification. Detection of calcification suggestive of DCIS should remain an important part of mammographic screening.     

Effect of multiple coil closure of patent ductus arteriosus on blood flow to the left lung as determined by lung perfusion scans

This paper describes a combined inpatient and partial hospital program, with a ten-bed short-term inpatient unit and a partial hospital program that can accommodate 24 patients. Inpatients and partial hospital patients are treated together by the same staff in a program located in the partial hospital. The authors highlight features of the program that address the five elements of continuity: place, personnel, program, patient-peers, and plan for treatment. The discussion focuses on the importance of continuity in sustaining a combined unit; potential benefits for patients, families, staff, and trainees; attractiveness to third-party payers; and impediments to fully realizing the potential of the unit.     

Improving patient care by reporting problems with medical devices

Healthcare practitioners are the primary users of medical devices for direct patient care. As such, they are in the best position to recognize problems that result from the use of medical devices. The outcome of a device-related adverse event or product problem, as with any other medical product, can be serious and result in illness injury, or even death. The sooner that FDA learns about a problem, the sooner the agency can take action to protect patient and user safety. Healthcare practitioners are major contributors to the knowledge base related to device use and safety through astute monitoring, rapid identification of device-related problems, and reporting these problems. An understanding of the voluntary and mandatory mechanism of reporting will ensure that device problems are reported appropriately and in a timely manner. As the primary users of medical equipment for direct patient care, health care professionals have the training and expertise to improve patient care by reporting actual and suspected problems with medical devices.     

The effect of complete versus incomplete information on odour discrimination in a parasitic wasp

We studied the function of learning in the parasitoid Leptopilina heterotoma by looking at discrimination of odour stimuli used in foraging for a host. To optimize the rate of encounters with hosts, these parasitoids are expected to assess the extent to which variation in host-substrate odours is reliably associated with variation in the presence of hosts, that is, substrate profitability. Where the association is reliable, parasitoids should attend to variation in odours and discriminate between them; where it is not, they should ignore it. We hypothesized that foraging decisions are based on the completeness of information the animal has about differences in substrate profitabilities. Our laboratory studies showed that discrimination and non-discrimination of odour stimuli are dynamic behavioural decisions that can be related to the degree of substrate variation and to an animal's informational state. In wind-tunnel studies, females learned to discriminate between odours from substrates that were qualitatively different, for example, between odours from apple and pear substrates or between yeast substrates with different C6 compounds added. They did not discriminate when differences were small (e.g. between odours from two apple varieties or between yeast patches with different concentrations of ethyl acetate), unless unrewarding experiences provided evidence of the absence of hosts in one of the substrates. Hence, we suggest that non-discrimination between odour stimuli in L. heterotoma is not a lack of ability to discriminate but a functional decision by the parasitoid. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Indocyanine green angiography of multifocal choroiditis

PURPOSE: The purpose of the study is to determine indocyanine green (ICG) angiographic characteristics of patients with multifocal choroiditis (MC) and to identify features that may assist in the differentiation of MC from other ocular inflammatory diseases. METHODS: After complete ophthalmologic examination, fluorescein angiography and ICG angiography were performed in a series of 14 patients with MC. The ICG findings were then correlated with the clinical and fluorescein angiographic appearance of these patients to determine specific characteristics and distinguishing features of the entity. These findings then were compared with those of angiographic patterns observed in patients with ocular histoplasmosis syndrome to determine whether differentiating features could be identified. RESULTS: Fourteen (50%) of the 28 eyes were found to have large hypofluorescent spots in the posterior pole on ICG angiography, which, in most cases, did not correspond to clinically or fluorescein angiographically detectable lesions. Seventeen (61%) had smaller hypofluorescent lesions (approximately 50 pm in size) in the posterior pole on the ICG study. In seven eyes exhibiting enlarged blind spots on visual field testing, ICG angiography showed confluent hypofluorescence surrounding the optic nerve. The ICG angiogram was found useful in evaluating the natural course in two patients with MC as well as a response to oral prednisone therapy in four others. The ICG angiographic findings differed from those seen in patients with ocular histoplasmosis. CONCLUSIONS: Indocyanine green angiography can provide information that is not detectable by clinical or fluorescein angiographic examination in patients with MC. This information may prove useful in differentiating this condition from the ocular histoplasmosis syndrome, provide a better understanding of the natural course and progression of the disease, and provide a potential adjunct in the clinical evaluation of patients undergoing therapeutic regimens for active inflammatory lesions.     

Genomic instability and catalase gene amplification induced by chronic exposure to oxidative stress

Chronic exposure (>200 days) of HA1 fibroblasts to increasing concentrations of H2O2 or O2 results in the development of a stable oxidative stress-resistant phenotype characterized by increased cellular antioxidant levels, particularly catalase (D. R. Spitz et al, Arch. Biochem. Biophys., 279: 249-260, 1990; D. R. Spitz et al., Arch. Biochem. Biophys., 292: 221-227, 1992; S. J. Sullivan et al., Am. J. Physiol. (Lung Cell. Mol. Physiol.), 262: L748-L756, 1992). Acutely stressed cells failed to develop a stably resistant phenotype or increased catalase activity, suggesting that chronic exposure is required for the development of this phenotype. This study investigates the mechanism underlying increased catalase activity in the H2O2- and O2-resistant cell lines. In H2O2- and O2-resistant cells, catalase activity was found to be 20-30-fold higher than that in the parental HA1 cells and correlated with increased immunoreactive catalase protein and steady-state catalase mRNA levels. Resistant cell lines also demonstrated a 4-6-fold increase in catalase gene copy number by Southern blot analysis, which is indicative of gene amplification. Chromosome banding and in situ hybridization studies identified a single amplified catalase gene site located on a rearranged chromosome with banding similarities to Z-4 in the hamster fibroblast karyotype. Simultaneous in situ hybridization with a Z-4-specific adenine phosphoribosyltransferase (APRT) gene revealed that the amplified catalase genes were located proximate to APRT on the same chromosome in all resistant cells. In contrast, HA1 cells contained only single copies of the catalase gene that were not located on APRT-containing chromosomes, indicating that amplification is associated with a chromosomal rearrangement possibly involving Z-4. The fact that chronic exposure of HA1 cells to either HO2 or 95% O2 resulted in gene amplification suggests that gene amplification represents a generalized response to oxidative stress, contributing to the development of resistant phenotypes. These results support the hypothesis that chronic exposure to endogenous metabolic or exogenous environmental oxidative stress represents an important factor contributing to gene amplification and genomic instability.     

"Flocculus neonatorum": a self-resolving benign nodular flocculus of the iris in the newborn

A severely resorbed maxilla was reconstructed utilizing a combined surgical technique that included the placement of a horseshoe-shaped bicortical calvarium onlay graft, fixed by six endosseous implants. Two more implants were placed in the pterygoid process to support and stabilize the prosthesis. The dentition was rehabilitated with a fixed implant-supported hybrid prosthesis.