Phylogenetic relationships within hump-winged grigs, Cyphoderris (Insecta, Orthoptera, Tettigonioidea, Haglidae)

The genus Cyphoderris, or hump-winged grigs, is represented by three species of cold-adapted, acoustic Ensifera with a geographic distribution that is generally restricted to the high-elevation coniferous forests of western North America. A phylogenetic analysis based on 29 morphological and 3 behavioural characters produced one tree, (C. buckelli (C. strepitans, C. monstrosa)) with a consistency index of 1.0. We discuss possible explanations for the observation that almost all of the autapomorphic change was concentrated in C. monstrosa.

Comparison of radiology residency programs in ten countries

The purpose of our study was to compare various aspects of radiology training schemes in ten countries. A questionnaire was sent to senior residents in the UK, USA, Canada, Australia, New Zealand, Italy, Egypt, India, Malaysia and Greece. The questions concerned length of training, required pre-training experience, the organization of the training scheme, teaching, resources, stages at which residents can independently perform and report examinations, fellowships, and progression to jobs. A wide variety of training, ranging from highly scheduled programs with detailed aims and objectives, to self-learning occurs across the world. Examinations and assessments are also variable. There are lessons to be learned from varying practices; more exchanges of ideas should be encouraged. In view of the "internationalization" of radiology services and the variation in training styles an international qualification for quality assurance purposes may be desirable.

Epidemiological differences between adenocarcinoma of the oesophagus and adenocarcinoma of the gastric cardia in the USA

BACKGROUND AND AIMS

It has been suggested that gastric cardia adenocarcinoma (GCA) is a distinct entity from oesophageal adenocarcinoma (OA). We examined several epidemiological features of GCA and OA in the USA to elucidate differences/similarities between these malignancies.

METHODS

Using the database of Surveillance, Epidemiology, and End Results (SEER) program, we examined incidence rates for temporal changes, and ethnic and age distributions, and performed birth cohort analyses for cases with morphologically and histologically confirmed OA or GCA.

RESULTS

The age adjusted incidence rates of OA rose progressively, reaching 1.8 per 100 000 (95% confidence interval 1.7-1.9) during 1987-1991 and 2.5 per 100 000 (2.3-2.6) during 1992-1996. In 1992-1996, Whites were affected five times more than Blacks, and men eight times more than women. A significant increase in incidence occurred among younger persons aged 45-65 years. Irrespective of age, OA was characterised by higher incidence rates among more recent birth cohorts: a 40% increase in incidence for each five year increase in the date of birth--a "birth cohort effect". On the other hand, the incidence rates of GCA reached their highest level of 3.3 per 100 000 (3.2-3.4) in 1987-1991 and subsequently declined during 1992-1996 to 3.1 per 100 000 (3.0-3.3). Whites were affected twice more than blacks and men five times more than women. Most patients with GCA were older than 60 years with no increase among younger persons and no birth cohort effect (p=0.99).

CONCLUSION

Several significant epidemiological differences exist between OA and GCA. These differences suggest that these two malignancies are separate entities with different risk factors.

Iron and zinc bioavailability in rats fed intrinsically labeled bean and bean-rice infant weaning food products

Beans are the core of the Latin American diet and contain iron and zinc. However, the bioavailability of these trace minerals from beans is low. The objective of this study was to determine if the bioavailability of iron and zinc could be improved with the use of fermentation and germination processing technologies. Black beans native to Costa Rica were grown hydroponically with either radioactive iron or zinc. The influence of fermentation and germination on iron and zinc bioavailability from intrinsically labeled infant weaning food products based on black beans and beans-rice was determined in rats. Mineral bioavailability was determined using whole-body (59)Fe retention for iron, and whole-body (65)Zn retention and incorporation of radiolabel into bone for zinc. Percent absorption of (59)Fe from fermented products ranged between 48.0 and 58.0. Percent absorption of (65)Zn ranged from 57.0 to 64.0. Fermentation did not increase iron bioavailability in rats fed fermented beans without rice. Fermentation of cooked beans significantly increased zinc retention. Germination significantly enhanced iron retention from cooked beans from 46 to 55% and from cooked beans-cooked rice from 34 to 48%. Germination significantly improved zinc absorption and retention from cooked beans without added rice.

Protein digestibility-corrected amino acid scores for bean and bean-rice infant weaning food products

Vegetable proteins are an integral part of infant weaning diets in Latin America. Protein quality in plant-based products, however, is constrained by amino acid composition and intrinsically present antinutritional factors. The goal of this study was to improve bean protein quality by utilizing fermentation and germination processing. The objectives were to determine if protein quality, as measured by Food and Agricultural Organization (FAO) approved True Protein Digestibility (TPD) and Protein Digestibility-Corrected Amino Acid Scores (PDCAAS), of formulated bean-based weaning products could be improved upon fermentation and germination and if protein quality could be further improved when processed beans were combined with cooked rice. Results showed that the highest TPD and PDCAAS values were obtained for cooked germinated beans combined with rice. The TPD values for products ranged from 80 to 91%, and the PDCAAS values were 0.38-0.51. There was no significant increase (P < 0.05) of either TPD or PDCAAS values upon fermentation. Germination increased TPD of cooked bean products; this increase was not, however, accompanied by an increase in PDCAAS. When combined with rice, the PDCAAS values for all bean products improved significantly, thus supporting the concept of cereal-legume complementation. In conclusion, this study showed the range of PDCAAS in processed black bean and bean-rice infant weaning food products. The potential for incorporation of these products into the diets of weaning age Latin American children would, however, be confirmed only after validation with growth or metabolic balance studies in human infants.

Hyperacute directional hearing in a microscale auditory system

The physics of sound propagation imposes fundamental constraints on sound localization: for a given frequency, the smaller the receiver, the smaller the available cues. Thus, the creation of nanoscale acoustic microphones with directional sensitivity is very difficult. The fly Ormia ochracea possesses an unusual 'ear' that largely overcomes these physical constraints; attempts to exploit principles derived from O. ochracea for improved hearing aids are now in progress. Here we report that O. ochracea can behaviourally localize a salient sound source with a precision equal to that of humans. Despite its small size and minuscule interaural cues, the fly localizes sound sources to within 2 degrees azimuth. As the fly's eardrums are less than 0.5 mm apart, localization cues are around 50 ns. Directional information is represented in the auditory system by the relative timing of receptor responses in the two ears. Low-jitter, phasic receptor responses are pooled to achieve hyperacute timecoding. These results demonstrate that nanoscale/microscale directional microphones patterned after O. ochracea have the potential for highly accurate directional sensitivity, independent of their size. Notably, in the fly itself this performance is dependent on a newly discovered set of specific coding strategies employed by the nervous system.

Trends in survival of patients with hepatocellular carcinoma between 1977 and 1996 in the United States

The recent increase in the incidence of hepatocellular cancer in the United States is thought to underlie the rising mortality of this malignancy. However, it remains unknown whether survival of patients with hepatocellular carcinoma (HCC) has changed during the same time period. Using the SEER database (Surveillance, Epidemiology, and End Results) of the National Cancer Institute, we examined the temporal changes and determinants of survival among patients with histologically proven HCC over a 20-year period. Between 1977 and 1996, 7,389 patients diagnosed with HCC were followed in the survival database of SEER. The overall 1-year relative survival rate increased from 14% (95% confidence intervals (CI): 12-16) during 1977-1981 to 23% (95% CI: 21-24) during 1992 to 1996. Between the same two time periods, less improvement was seen in the 5-year survival rates, which increased from 2% (95% CI: 1-3) to only 5% (95% CI: 4-7). The median survival increased slightly from 0.57 years during 1977 to 1981 to 0.64 years during 1992 to 1996. In general, there were no significant differences in survival between men and women or between ethnic groups. During 1987 to 1991, a small fraction (0.8%) of patients underwent radical surgery; these patients had 1-year survival of 59% (95% CI: 35-83%), and 5-year survival of 35% (95% CI: 12-58%). Similar rates were seen during 1992-1996. In conclusion, a small improvement in survival of patients with HCC was seen between 1977 and 1996. Most of this apparent benefit is restricted to the first year following cancer diagnosis, raising the possibility of lead-time bias. There were no significant differences related to gender or ethnicity.

Trends in survival of patients with hepatocellular carcinoma between 1977 and 1996 in the United States

The recent increase in the incidence of hepatocellular cancer in the United States is thought to underlie the rising mortality of this malignancy. However, it remains unknown whether survival of patients with hepatocellular carcinoma (HCC) has changed during the same time period. Using the SEER database (Surveillance, Epidemiology, and End Results) of the National Cancer Institute, we examined the temporal changes and determinants of survival among patients with histologically proven HCC over a 20-year period. Between 1977 and 1996, 7,389 patients diagnosed with HCC were followed in the survival database of SEER. The overall 1-year relative survival rate increased from 14% (95% confidence intervals (CI): 12-16) during 1977-1981 to 23% (95% CI: 21-24) during 1992 to 1996. Between the same two time periods, less improvement was seen in the 5-year survival rates, which increased from 2% (95% CI: 1-3) to only 5% (95% CI: 4-7). The median survival increased slightly from 0.57 years during 1977 to 1981 to 0.64 years during 1992 to 1996. In general, there were no significant differences in survival between men and women or between ethnic groups. During 1987 to 1991, a small fraction (0.8%) of patients underwent radical surgery; these patients had 1-year survival of 59% (95% CI: 35-83%), and 5-year survival of 35% (95% CI: 12-58%). Similar rates were seen during 1992-1996. In conclusion, a small improvement in survival of patients with HCC was seen between 1977 and 1996. Most of this apparent benefit is restricted to the first year following cancer diagnosis, raising the possibility of lead-time bias. There were no significant differences related to gender or ethnicity.

Risk factors for the rising rates of primary liver cancer in the United States

BACKGROUND

A recent increase in the incidence of hepatocellular carcinoma was reported in the United States. The cause of this witnessed rise remains unknown.

METHODS

We examined the temporal changes in both age-specific and age-standardized hospitalization rates of primary liver cancer associated with hepatitis C, hepatitis B, and alcoholic cirrhosis in the Department of Veterans Affairs Medical Center's Patient Treatment File.

RESULTS

A total of 1605 patients were diagnosed with primary liver cancer between 1993 and 1998. The overall age-adjusted proportional hospitalization rate for primary liver cancer increased from 36.4 per 100,000 (95% confidence interval [CI], 34.0-38.9) between 1993 and 1995 to 47.5 per 100,000 (95% CI, 44.6-50.1) between 1996 and 1998. There was a 3-fold increase in the age-adjusted rates for primary liver cancer associated with hepatitis C virus, from 2.3 per 100,000 (95% CI, 1. 8-3.0) between 1993 and 1995 to 7.0 per 100,000 (95% CI, 5.9-8.1) between 1996 and 1998. Concomitant with this rise, the age-specific rates for primary liver cancer associated with hepatitis C also shifted toward younger patients. During the same periods, the age-adjusted rates for primary liver cancer associated with either hepatitis B virus (2.2 vs 3.1 per 100,000) or alcoholic cirrhosis (8. 4 vs 9.1 per 100,000) remained stable. The rates for primary liver cancer without risk factors also remained without a statistically significant change, from 17.5 (95% CI, 15.8-19.1) between 1993 and 1995 to 19.0 per 100,000 (95% CI, 17.3-20.7) between 1996 and 1998.

CONCLUSIONS

Hepatitis C virus infection accounts for most of the increase in the number of cases of primary liver cancer among US veterans. The rates of primary liver cancer associated with alcoholic cirrhosis and hepatitis B virus infection have remained stable. Arch Intern Med. 2000;160:3227-3230.

Occult craniocerebral injuries from dog bites in young children

Although dog bite injuries to the head and scalp of children occur frequently, penetrating dog bite wounds to the cranial vault occur only occasionally and may go unnoticed on initial examination. Substantial morbidity and mortality can ensue if these penetrating injuries are not detected and treated. The authors detail the evaluation of dog bites of the scalp in young children. They highlight the ease with which puncture wounds of the calvarium may be missed during physical examination as a result of scalp displacement at the time of puncture. The cranial puncture may not be large and may later be covered by scalp that returns to its native position. Well-scrutinized skull films and a careful, methodical physical examination are advocated. Recognized craniocerebral injuries should be explored. Depressed cranial fractures should be irrigated, debrided, and elevated. Dural tears should be repaired. Expedient management is necessary to prevent meningitis and its associated sequelae.

Low grade gastric MALT Lymphoma: radiographic findings

AIMS

Gastric MALT (mucosa-associated lymphoid tissue) lymphoma is now recognized as a distinct entity within extranodal non-Hodgkin's lymphoma. The purpose of this study was to describe the radiographic findings in low grade gastric MALT lymphoma.

MATERIALS AND METHODS

We retrospectively reviewed the radiographic findings in 22 cases of low-grade gastric MALT lymphoma. The study group consisted of 15 men and seven women (median age 68 years, range 41-91 years). Lesions were designated as infiltrative or polypoid by consensus of two radiologists. Polypoid lesions were categorized by number and size. Anatomical site within the stomach and presence of transpyloric or oesophagogastric extension was determined for each case. The presence of abdominal lymphadenopathy was categorized as regional or distant. The presence of Helicobacter pylori was determined from endoscopic and surgical biopsies.

RESULTS

Computed tomography (CT) revealed abnormalities of the stomach in 19 cases of the 21 in which it was performed. There were 14 infiltrative lesions and five polypoid lesions. Of the 14 infiltrative lesions, the mean gastric wall thickness was 2.2 cm (range 0.8-6.0 cm). There were three single and two multiple polypoid lesions (mean size 2.2 cm, range 1. 5-2.7 cm). Transpyloric extension was observed in two cases and oesophagogastric extension in one. Abdominal lymphadenopathy was observed in 10 of 21 patients. Helicobacter pylori was found in 19 of 22 cases (86%).

CONCLUSION

Low grade B cell gastric MALT lymphomas present with an infiltrative form on CT in about three-quarters of cases and a polypoid pattern in the remainder. Abdominal lymphadenopathy is seen in approximately one-half of cases. There is a high association with Helicobacter pylori.

Management of alcohol withdrawal in microvascular head and neck reconstruction

Alcohol use is a risk factor for head and neck cancer. One of the primary therapeutic modalities is surgical tumor ablation followed by immediate reconstruction. Such therapy places patients in a controlled environment, without alcohol, creating the risk of alcohol withdrawal syndrome. The authors attempted to identify the incidence of alcohol withdrawal among patients undergoing free-flap reconstruction for head and neck cancer and were interested in the effect of alcohol withdrawal on the postoperative course of affected patients. In this retrospective review of 51 patients, six experienced alcohol withdrawal or delirium tremens. No difference in the rate of overall complications was seen between the patients who experienced withdrawal and those who did not, although patients who experienced withdrawal did have a statistically significant ratio of non-flap-related to flap-related complications. A review of the current management for alcohol withdrawal is included and places an emphasis on preoperative screening, close observation, rapid diagnosis, and immediate medical care.

An infected mediastinal cyst

The authors describe a 43-year-old patient who had a mediastinal mass that became infected after a transbronchial needle aspirate biopsy. A paraspinal, extrapleural window with a saline-lidocaine mixture was created that allowed the placement of a percutaneous drainage catheter into the infected lesion. This procedure resulted in an excellent clinical outcome, and obviated the need for a thoracotomy and more invasive surgical management.

Revascularization of the upper extremity in a preterm infant: a case report and review of the literature

Upper extremity arterial injuries in preterm infants are usually of iatrogenic origin. Current microsurgical techniques permit extremity revascularization in these patients. The authors report the microsurgical repair of a 0.7-mm brachial artery in a 940-g preterm infant. The preterm infant warrants special consideration due to physiological immaturity. Rapid fluid shifts, a relative polycythemia, and the potential for low cardiac output states increase the risk for vascular thrombosis. Systemic heparinization is contraindicated in this population due to the risk of intraventricular hemorrhage. Optimization of various physiological variables should reduce the risk of thrombosis.

Tissue expander infections in children: look beyond the expander pocket

Infection of the expander pocket is the most common complication encountered with soft-tissue expansion. It is usually due to direct inoculation with skin flora either at the time of expander insertion or from extrusion of the device. The authors report two cases of infection of tissue expanders in which the children had concomitant infected sites distant from the prosthesis. Etiological bacteria of common pediatric infections like otitis media and pharyngitis were cultured from the infected expander pocket, raising suspicion that translocation of the organism to the expander had occurred. Aggressive antibiotic treatment, removal of the prosthesis, and flap advancement is advocated.

Newly diagnosed cystic fibrosis in adults: pattern and distribution of bronchiectasis in 12 cases

OBJECTIVE

The aim of this study was to analyse the type and distribution of bronchiectasis at computed tomography (CT) in adults with recently diagnosed cystic fibrosis.

METHODS

The CT examinations of 12 consecutive patients diagnosed with cystic fibrosis in adulthood (six male, six female; age range at diagnosis 25-63 years) were analysed retrospectively using a modified Bhalla scoring system. Bronchiectasis was catergorized by Reid type and by location within the affected lobe (peripheral, central or mixed).

RESULTS

Bronchiectasis was identified in 70 of 71 lobes. Two or more bronchopulmonary segments were involved in 67 of 71 lobes. The majority of lobes demonstrated cylindrical bronchiectasis as the predominant type (n = 51), with varicose (n = 11) and cystic (n = 8) less commonly seen. Bronchiectasis was mainly central in 16 lobes, and both central and peripheral in 54 lobes. The severity of bronchial dilatation was greatest for the upper lobes (mean score, 1.75 right, 1.58 left) compared with the middle lobe/lingula (mean score, 1.42 right, 1.17 left) and lower lobes (mean score, 1.09 right, 1.17 left).

CONCLUSION

Bronchiectasis in patients with cystic fibrosis diagnosed in adulthood is usually widespread, predominantly cylindrical, and is more severe in the upper lobes. The diagnosis of cystic fibrosis should be considered in adults with 'idiopathic' bronchiectasis showing these features on CT.

Bronchiectasis: accuracy of high-resolution CT in the differentiation of specific diseases

OBJECTIVE

The aim of the study was to determine whether various causes of bronchiectasis can be differentiated by the pattern and distribution of abnormalities seen on high-resolution CT.

MATERIALS AND METHODS

The retrospective study included 82 consecutive patients who had a specific diagnosis of bronchiectasis proven by appropriate clinical and laboratory criteria. All patients underwent high-resolution CT scanning (1- to 1.5-mm collimation). The CT scans were assessed for the presence, extent, type, and anatomic distribution of bronchiectasis by two independent observers who were not aware of the clinical data. The observers recorded their most likely diagnosis and the degree of confidence in that diagnosis.

RESULTS

The two independent observers made a correct diagnosis in 61% of cases (100/164 interpretations). On average, a correct diagnosis was made in 19 (68%) of 28 cases of cystic fibrosis, 16 (67%) of 24 cases of previous tuberculosis, six (43%) of 14 cases of previous childhood infection, five (56%) of nine cases of allergic bronchopulmonary aspergillosis, and four (57%) of seven cases of other causes of bronchiectasis. We found moderate agreement between the observers for the correct diagnosis (kappa = .53) and good agreement for the presence or absence of bronchiectasis in each lobe (kappa = .71).

CONCLUSION

The pattern and distribution of abnormalities revealed by high-resolution CT in patients with bronchiectasis are influenced by the underlying cause. Bilateral, predominantly upper lobe, bronchiectasis is seen most commonly in patients with cystic fibrosis and allergic bronchopulmonary aspergillosis, unilateral upper lobe predominance in patients with tuberculosis, and lower lobe predominance in patients after childhood viral infection.

Thoracic foreign bodies in adults

AIM

The aim of this pictorial essay is to illustrate a range of imaging manifestations of thoracic foreign bodies.

METHODS AND RESULTS

The essay includes documented intrathoracic foreign bodies introduced by inhalation, aspiration, penetrating trauma or ingestion. Imaging modalities include chest radiography and computed tomography (CT).

CONCLUSIONS

The majority of foreign bodies are seen on the plain chest radiograph. CT is helpful in demonstrating the presence of radiolucent foreign bodies and determining the exact location of the foreign bodies within the airways or lung parenchyma.

Peripheral frequency mis-match in the primitive ensiferan Cyphoderris monstrosa (Orthoptera: Haglidae)

Peripheral auditory frequency tuning in the ensiferan insect Cyphoderris monstrosa (Orthoptera: Haglidae) was examined by comparing tympanal vibrations and primary auditory receptor responses. In this species there is a mis-match between the frequency of maximal auditory sensitivity and the frequency content of the species' acoustic signals. The mis-match is not a function of the mechanical properties of the tympanum, but is evident at the level of primary receptors. There are two classes of primary receptors: low-tuned and broadly tuned. Differences in the absolute sensitivity of the two receptor types at the male song frequency would allow the auditory system to discriminate intraspecific signals from sounds containing lower frequencies. Comparisons of tympanal and receptor tuning indicated that the sensitivity of the broadly tuned receptors did not differ from that of the tympanum, while low-tuned receptors had significantly narrower frequency tuning. The results suggest that the limited specialization for the encoding of intraspecific signals in the auditory system of C. monstrosa is a primitive rather than a degenerate condition. The limited specialization of C. monstrosa may reflect the evolutionary origin of communication-related hearing from a generalized precursor through the addition of peripheral adaptations (tympana, additional receptors) to enhance frequency sensitivity and discrimination.

Rising incidence of hepatocellular carcinoma in the United States

BACKGROUND AND METHODS

Clinical observations have suggested that the number of cases of hepatocellular carcinoma has increased in the United States. We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) data base to determine the age-adjusted incidence of hepatocellular carcinoma from 1976 to 1995, data from the U.S. vital-statistics data base to determine age-adjusted mortality rates from 1981 to 1995, and data from the Department of Veterans Affairs to determine age-adjusted rates of hospitalization for the disease from 1983 to 1997.

RESULTS

The incidence of histologically proved hepatocellular carcinoma increased from 1.4 per 100,000 population (95 percent confidence interval, 1.3 to 1.4) for the period from 1976 to 1980 to 2.4 per 100,000 (95 percent confidence interval, 2.3 to 2.4) for the period from 1991 to 1995. Among black men, the incidence was 6.1 per 100,000 for the period from 1991 to 1995, and among white men, it was 2.8 per 100,000. There was a 41 percent increase in the mortality rate from primary liver cancer and a 46 percent increase in the proportion of hospitalizations attributable to this disease during the periods studied. The incidence increased significantly among younger persons (40 to 60 years old) during the period from 1991 to 1995 as compared with earlier periods.

CONCLUSIONS

An increase in the number of cases of hepatocellular carcinoma has occurred in the United States over the past two decades. The age-specific incidence of this cancer has progressively shifted toward younger people.

Accuracy of CT for the detection of pleural adhesions: correlation with video-assisted thoracoscopic surgery

STUDY OBJECTIVE

The presence of pleural adhesions may render video-assisted thoracoscopic surgery (VATS) difficult or impossible. The aim of this study was to assess the value of chest CT in the detection of pleural adhesions prior to VATS.

DESIGN

Prospective study of the accuracy of chest CT in detecting pleural adhesions prior to VATS.

SETTING

Tertiary-referra; teaching hospital and Veterans Administration hospital.

PATIENTS

Between July 1994 and March 1995, 63 consecutive patients undergoing 64 VATS procedures were evaluated with chest CT prior to surgery.

MEASUREMENTS AND RESULTS

Preoperative scans were interpreted by consensus of two pulmonary radiologists prior to surgery. Suspected pleural adhesions and other findings related to the pleura were recorded on a form given to the surgeon prior to VATS. The surgeon confirmed or excluded each suspected adhesion during VATS, and documented any other lesions not identified preoperatively. Patient-by-patient and lesion-by-lesion analyses were performed. Pleural adhesions were correctly identified by CT in 28 of 39 cases (sensitivity, 71%) and excluded in 18 of 25 cases (specificity, 72%). On a lesion-by-lesion basis, 73 adhesions were identified during VATS, of which only 28 were identified prospectively at CT. There were 45 missed adhesions and 20 adhesions that were suggested falsely (sensitivity, 38%; specificity, 46%). Eighteen pleural spaces were correctly identified as being free of pleural adhesions.

CONCLUSIONS

CT is moderately sensitive and specific for preoperative identification of pleural adhesions in patients undergoing VATS but its accuracy is poorer for individual lesions.

Hearing in mole crickets (Orthoptera: gryllotalpidae) at sonic and ultrasonic frequencies

We have studied auditory responses in two species of mole cricket (Scapteriscus borellii and S. abbreviatus) to determine (1) whether they show sensitivity to ultrasound, (2) whether their hearing (at both low and high frequencies) is based on the same neural circuitry as that of true crickets, and (3) whether ultrasound sensitivity in different mole cricket species varies with their ability to fly. S. borellii are sensitive to ultrasonic frequencies. There is evidence of a segregation of frequency bands in prothoracic auditory neurons. There are two pairs of &ohgr ; neurons (ONs) with similar morphology to ON1 of true crickets. The two pairs of ONs differ in tuning. One pair has two sensitivity peaks: at the frequency of the calling song of this species (3 kHz), and in the ultrasonic range (25 kHz). The other pair lacks the high-frequency sensitivity and responds exclusively to frequencies in the range of the species song. These two types are not morphologically distinguishable. In S. abbreviatus, only one class of ON was found. S. abbreviatus ONs are narrowly tuned to the frequency of the species' calls. A T-neuron had the best ultrasonic frequency sensitivity in S. borellii. This cell showed a broad tuning to ultrasonic frequencies and was inhibited by low-frequency stimuli. A morphologically similar neuron was also recorded in S. abbreviatus, but lacked the high-frequency sensitivity peak of that in S. borellii. We also assessed the responses of flying S. borellii to ultrasound using field playbacks to free-flying animals. The attractiveness of broadcast calling song was diminished by the addition of an ultrasound signal, indicating that S. borellii avoid high-frequency sound. The results indicate that mole crickets process low-frequency auditory stimuli using mechanisms similar to those of true crickets. They show a negative behavioural response to high-frequency stimuli, as do true crickets, but the organization of ultrasound-sensitive auditory circuitry in mole crickets differs from that of true crickets.

Hearing in mole crickets (Orthoptera: Gryllotalpidae) at sonic and ultrasonic frequencies

We have studied auditory responses in two species of mole cricket (Scapteriscus borellii and S. abbreviatus) to determine (1) whether they show sensitivity to ultrasound, (2) whether their hearing (at both low and high frequencies) is based on the same neural circuitry as that of true crickets, and (3) whether ultrasound sensitivity in different mole cricket species varies with their ability to fly. S. borellii are sensitive to ultrasonic frequencies. There is evidence of a segregation of frequency bands in prothoracic auditory neurons. There are two pairs of omega neurons (ONs) with similar morphology to ON1 of true crickets. The two pairs of ONs differ in tuning. One pair has two sensitivity peaks: at the frequency of the calling song of this species (3 kHz), and in the ultrasonic range (25 kHz). The other pair lacks the high-frequency sensitivity and responds exclusively to frequencies in the range of the species song. These two types are not morphologically distinguishable. In S. abbreviatus, only one class of ON was found. S. abbreviatus ONs are narrowly tuned to the frequency of the species' calls. A T-neuron had the best ultrasonic frequency sensitivity in S. borellii. This cell showed a broad tuning to ultrasonic frequencies and was inhibited by low-frequency stimuli. A morphologically similar neuron was also recorded in S. abbreviatus, but lacked the high-frequency sensitivity peak of that in S. borellii. We also assessed the responses of flying S. borellii to ultrasound using field playbacks to free-flying animals. The attractiveness of broadcast calling song was diminished by the addition of an ultrasound signal, indicating that S. borellii avoid high-frequency sound. The results indicate that mole crickets process low-frequency auditory stimuli using mechanisms similar to those of true crickets. They show a negative behavioural response to high-frequency stimuli, as do true crickets, but the organization of ultrasound-sensitive auditory circuitry in mole crickets differs from that of true crickets.

The role of computed tomography in the diagnosis and management of human immunodeficiency virus (HIV)-related pulmonary diseases

This review summarizes the current role of CT in the diagnosis and management of respiratory disease in human immunodeficiency virus (HIV)-positive patients. Recommendations are made concerning optimum technique for diagnostic CT as well as practical considerations concerning the use of CT in biopsy and thoracic interventional procedures in acquired immune deficiency syndrome (AIDS)-related thoracic disease. Clinical scenarios discussed include the use of CT when the chest radiograph is normal in a patient with a high clinical suspicion of pulmonary disease, utility of CT in the differential diagnosis of parenchymal abnormalities and in the assessment of patients with airways disease, hemoptysis, progressive lung disease, and intrathoracic complications. Finally, the use of thoracic CT in the staging of AIDS-related neoplastic conditions involving the chest is discussed.

The role of radiologic imaging in diagnosing complications of video-assisted thoracoscopic surgery

STUDY OBJECTIVE

To examine the role of radiologic imaging in evaluating complications of video-assisted thoracoscopic surgery.

DESIGN

Retrospective review of radiographic and clinical data.

SETTING

Tertiary referral hospital.

PATIENTS

All patients who underwent thoracoscopy at the University of Maryland Hospital between July 1990 and June 1994. A total of 260 procedures were performed on 239 patients.

MEASUREMENTS AND RESULTS

Imaging studies performed before, during, and after surgery in cases in which complications occurred were reviewed by two thoracic radiologists. A randomly selected group of 22 CT scans from uncomplicated cases were used as control subjects. Complications occurred in 24 (9.2%) of the 260 thoracoscopic procedures. Intraoperative complications developed in 14 (5.4%) patients. Ten of the 14 patients had an obliterated pleural space that prevented access of the trocars and videoscope. Preoperative imaging showed significant pleural thickening or calcifications in seven of these ten patients. Other intraoperative complications were malposition of the double-lumen endotracheal tube (n=2) and dislodgement of a localizing needle-wire (n=2). In 8 (3.1%) patients, radiographically evident postoperative complications developed; these complications included prolonged air leak, empyema, recurrent pneumothorax, pulmonary edema, and pneumonia.

CONCLUSION

Pleural calcification or thickening that is found on preoperative studies may help predict difficulty in inserting the thoracoscopic instruments but also can be seen on preoperative CT scans in uncomplicated cases. Thoracic CT scans may fail to predict complete pleural symphysis.

Nutrition Societies Presidents' Forum: future challenges and opportunities for nutrition societies in the 21st century

The Chair introduced "Pasteur's Quadrant" as a potentially useful paradigm for modern science. Developed by Princeton's Donald E Stokes, the quadrant is two-by-two matrix that classifies knowledge as fundamental and/or applied. The Chair also noted the effect of competitive pressures, and the necessity for cooperation among nutrition societies. The Presidents of The American Society for Nutritional Sciences (ASNS), The American Society for Clinical Nutrition (ASCN), The American Society for Parenteral and Enteral Nutrition (ASPEN), and the Chair of the Institute of Food Technologist's (IFT) Nutrition Division presented their views on how societies can prepare to meet their members' upcoming needs. The Director of the Center for Food and Nutrition Policy discussed the future role of nutrition societies and how they might interact with various interest groups. The Forum, which included an opportunity for audience participation, took place soon after the February 1996 release of "Meeting the Challenge: A Research Agenda for America's Health, Safety, and Food." Published by the Executive Office of the President's Office of Science and Technology Policy, the report highlights the importance of nutrition to our nation's health.

From the archives of the AFIP. Malignant pleural mesothelioma: radiologic-pathologic correlation

Malignant pleural mesothelioma (MPM) is a rare malignant neoplasm that typically affects individuals occupationally exposed to asbestos through a variety of industries. The patients experience an insidious onset of symptoms, including dyspnea, chest pain, cough, malaise, and weight loss. The pathologic diagnosis of MPM is difficult, and special stains or immunohistochemical or ultrastructural analysis may be required to differentiate MPM from metastatic adenocarcinoma. The tumor affects both the parietal and visceral pleural surfaces and progresses to encase the lung and invade the lung, mediastinum, and chest wall. Radiologically, MPM manifests as unilateral pleural effusion, pleural nodules, or pleural masses. Imaging studies are useful for diagnosis and staging in patients who are potential surgical candidates. Although a variety of multimodality therapies are available and radical surgical procedures have been developed, the prognosis remains dismal.

Primary carcinoma of the lung overlooked at CT: analysis of findings in 14 patients

PURPOSE

To describe the appearances of overlooked lung cancer at computed tomographic (CT) examination and to analyze the reasons for failure to diagnose these lesions.

MATERIALS AND METHODS

Fourteen patients with 15 overlooked lung cancers were identified by radiologists at three institutions. Location, shape, and cell type of each cancer were reviewed, and other relevant findings of CT examinations were assessed.

RESULTS

The missed tumors manifested as endobronchial lesion (n = 10), solitary parenchymal nodule (n = 2), area of focal peripheral air-space disease (n = 2), or pleural-based thickening (n = 1). Eleven (73%) of the 15 lesions were located in a lower lobe. In six (43%) of 14 patients, major distracting findings were present elsewhere in the thorax.

CONCLUSION

Endobronchial location and lower lobe predominance were the most common characteristics of overlooked lung cancer at CT. The presence of unrelated major abnormalities at CT may also have contributed to failure to diagnose the tumor.

Bronchial artery aneurysms in association with Mycobacterium avium intracellulare complex

An immunosuppressed patient with scleroderma presented with hemoptysis due to bronchial artery aneurysms associated with Mycobacterium avium-intracellulare complex (MAC).

Informed consent for percutaneous lung biopsy: comparison of two consent protocols based on patient recall after the procedure

OBJECTIVE

Informed consent is now required for the majority of radiologic procedures, but few studies have evaluated the efficacy of informed consent protocols. We compared our standard consent protocol of obtaining consent prior to percutaneous lung biopsy with a modified protocol by using patients' recall of procedure risks after the biopsy as an indicator of patients' comprehension.

SUBJECTS AND METHODS

The study sample consisted of 50 patients who underwent percutaneous lung biopsy between December 1992 and June 1994. Twenty-seven patients received our standard informed consent procedure in which four important procedure risks were described briefly using our standard method. Twenty-three patients underwent a consent procedure that had the following modification. After the four procedure risks were described, the patient was tested verbally until all risks could be recited to the physician. This change required 5 additional min at most. In both protocols, efficacy of the procedure was evaluated by testing patient recall 4 hr after consent was obtained. We also assessed any effect that might have been introduced by differences between the groups, age, sex, time between consent and recall, and complications during the procedure.

RESULTS

Patients' recall was significantly better in the modified consent group than in the standard group (p = .005). This result could not be attributed to differences in age, sex, or time between consent and recall. There was a trend for improved recall in patients with complications. This trend did not appear to influence our principal finding.

CONCLUSION

The standard consent procedure for lung biopsy appears inadequate when patients' recall of procedure risks later is used as a measure of the patients' comprehension. Based on this study, the informed consent process may be improved substantially by teaching patients to recite the procedure risks to the physician as part of the informed consent protocol.

Calcification of aortic valve detected incidentally on CT scans: prevalence and clinical significance

OBJECTIVE

Aortic valve calcification that is visualized on chest radiographs is considered a marker for clinically significant aortic stenosis, but the clinical importance of this finding on CT is unknown. Accordingly, we studied the prevalence and clinical relevance of aortic valve calcification found incidentally on CT scans of the chest.

MATERIALS AND METHODS

After comparing computer records of chest CTs and echocardiograms, we identified 109 patients who underwent both studies during a 2-year period. Two thoracic radiologists reviewed the CT scans to identify and quantify aortic valve calcification. The quantity of aortic valve calcification was graded on a scale of 1 to 3, with grade 3 indicating the most severe calcification. The prevalence of calcification was correlated with patient age and sex. The findings on CT were correlated with hemodynamic data from echocardiography. At echocardiography, a peak aortic valve gradient of greater than 25 mm Hg was defined as abnormal.

RESULTS

Aortic valve calcification was noted on CT scans in 33 (30%) of the 109 patients. Aortic valve calcification shown by CT was significantly more common in patients more than 65 years old (p < .01). Five (15%) of 33 patients with aortic valve calcification shown by CT had abnormal aortic valve gradients at echocardiography. In contrast, none of 76 patients without aortic valve calcification shown by CT had abnormal aortic valve gradients (p < .01). All five patients with abnormal aortic valve gradients had moderate quantities of aortic valve calcification seen on CT scans. Two of the five were younger than 55 years old.

CONCLUSION

Aortic valve calcification is a common finding on CT scans and is usually clinically insignificant. Nevertheless, some patients with aortic valve calcification on CT have aortic stenosis, particularly those younger than 55 years old and those with moderately dense aortic valve calcification shown by CT. These patients may benefit from hemodynamic assessment of the aortic valve by echocardiography.

MR imaging of slipped stacked breast implants: a potential pitfall in the diagnosis of intracapsular rupture

The integrity of silicone-gel breast implants can be evaluated by MR imaging. The findings of intra- and extracapsular rupture have been described. Increasingly sophisticated breast reconstruction techniques such as stacking of prostheses have lead to a wider range of implant appearances. We report a case where intracapsular rupture was simulated by slippage of two retropectoral stacked implants in relation to each other. The MR and CT findings are described.

A comparison of learning activity packages and classroom instruction for diet management of patients with non-insulin-dependent diabetes mellitus

Forty patients were randomly assigned to receive either the individualized learning activity packages or classroom instruction. Effectiveness was evaluated on the basis of fasting plasma glucose, glycosylated hemoglobin, percent of ideal body weight, and knowledge and behavior scores. No significant differences were found between the groups at entry or at the 2-month follow-up. At the 5-month follow-up, the group that received the learning activity packages scored significantly higher on knowledge assessment, significantly increased their behavior score, and decreased their percent of ideal body weight. Patients who received classroom instruction increased their behavior score and exhibited significantly decreased glycosylated hemoglobin levels. Behavior and blood glucose levels were significantly correlated. Although the learning activity packages proved effective in increasing knowledge, no significant improvement was observed in blood glucose levels.

CT appearance of endobronchial non-Hodgkin lymphoma

OBJECTIVE

Endobronchial involvement by non-Hodgkin lymphoma (NHL) is a very rare manifestation of the disease. We describe this unusual entity and emphasize the role of chest CT scan.

MATERIALS AND METHODS

Two radiologists reviewed the chest radiographs and CT scans of two patients with endobronchial NHL. The studies were reviewed for the presence and extent of endobronchial involvement. Bronchoscopic confirmation was obtained.

RESULTS

In each case CT showed endobronchial lesions that correlated well with the extent of tumor found at bronchoscopy.

CONCLUSION

Computed tomography is useful to suggest endobronchial NHL in the proper clinical context and to assist the bronchoscopist in selecting the appropriate site for biopsy.

Value of radiograph audit in an accident service department

In our accident service department all trauma radiographs are reported acutely and those misinterpreted by the casualty officers are presented at the daily clinicoradiological conference. We have reviewed this practice over a 6-month period. From over 25,000 patients attending the accident service, 16,246 radiographs were requested and reported. Of these, 456 (2.8 per cent) were considered to have been potentially misinterpreted. The errors included 167 (1 per cent) missed fractures, 55 (0.3 per cent) suspected fractures and 72 (0.4 per cent) false-positive diagnoses of fracture. Subsequently, 114 (0.7 per cent) patients required recall for treatment or further imaging. Incorrect diagnoses were seen most frequently in the more commonly injured anatomical sites--the ankle, wrist, foot, elbow and hand. However, the incidence of misinterpretation was highest in examination of the fingers, especially in children. We believe that these low figures are principally the result of involving both orthopaedic surgeons and radiologists at the formal daily conference. We regard our system of audit as beneficial to patients' care and anticipate reduced litigation which may offset the increased cost of audit.

Growth hormone response to growth hormone releasing factor in diabetic men

Increased plasma concentrations of growth hormone (GH) are reported in diabetes and it is suggested that this may be important in the development of complications. We have investigated fasting GH levels and the response to 100 micrograms i.v. growth hormone releasing factor, GRF(1-29)NH2, in age-matched men: six normal weight controls, six obese controls, six insulin-dependent diabetics, six normal weight non-insulin dependent diabetics and six obese non-insulin dependent diabetics. None of the diabetic men had clinical evidence of diabetic complications. Fasting GH values did not differ significantly between the five groups. The peak GH response to GRF was similar in the controls, insulin-dependent diabetics (IDD) and non-insulin dependent (NIDD) normal weight diabetics (mean peak +/- SEM: controls 25.5 +/- 5 mU/l, IDD 26.5 +/- 6 mU/l, NIDD 19.7 +/- 5 mU/l) but was significantly reduced in the two obese groups (obese 6.4 +/- 3 mU/l, obese diabetics 4.5 +/- 1 mU/l, P less than 0.01). This impairment of GH secretion was unrelated to either fasting plasma insulin or glucose concentration. We conclude that our results do not confirm the previous reports of abnormal GH secretion in diabetes but do demonstrate a markedly impaired GH response to GRF to be a feature of obesity.

A study of the use of intravenous cannulas for medical emergencies in Newham--implications for financial savings

A study of intravenous (i.v.) cannula usage for medical emergencies admitted to hospitals in the Newham Health District was undertaken during two defined periods (24 and 35 days). Almost half the cannulas inserted (47%) were not flushed following an initial bolus injection of heparinized saline. The duration that cannulas remained in a vein ranged from 24 hours to 8 days (median 2 days) and inflammation around the cannula site was related to the length of time since insertion but unrelated to whether the cannula was flushed regularly or to the type of fluid used. Our findings indicate a substantial wastage of i.v. cannulas due to difficulties with insertion and suggest that isotonic saline, without heparin, is effective in maintaining cannula patency for 48 hours. It is concluded that these findings are not unique to the Newham Health District and worthwhile financial savings should be achieved throughout the NHS if clinicians reconsider the indications and use of i.v. cannulas for their patients.