Patterns of reticulate evolution for the classical class I and II HLA loci

Some alleles of the major histocompatibility complex (MHC) genes have a reticulate pattern of evolution, probably resulting from the exchange of segments by gene conversion or recombination. Here we compare the extent and patterns of reticulate evolution among the classical class I and class II loci of the human MHC using the recently developed compatibility and partition matrix methods. A complex pattern is revealed with substantial differences among loci in the extent and pattern of reticulation. Extremely high levels of reticulation are observed at HLA-B and HLA-DPB1, high levels at HLA-A and HLA-DRB1, moderate levels at HLA-C and HLA-DQB1, and low levels at HLA-DQA1. The reticulate events are concentrated in the exons encoding the highly variable, peptide-binding domains, suggesting that the sequence combinations produced by these events are maintained by natural selection.

Antigenicity of fullerenes: antibodies specific for fullerenes and their characteristics

The recent interest in using Buckminsterfullerene (fullerene) derivatives in biological systems raises the possibility of their assay by immunological procedures. This, in turn, leads to the question of the ability of these unprecedented polygonal structures, made up solely of carbon atoms, to induce the production of specific antibodies. Immunization of mice with a C60 fullerene derivative conjugated to bovine thyroglobulin yielded a population of fullerene-specific antibodies of the IgG isotype, showing that the immune repertoire was diverse enough to recognize and process fullerenes as protein conjugates. The population of antibodies included a subpopulation that crossreacted with a C70 fullerene as determined by immune precipitation and ELISA procedures. These assays were made possible by the synthesis of water-soluble fullerene derivatives, including bovine and rabbit serum albumin conjugates and derivatives of trilysine and pentalysine, all of which were characterized as to the extent of substitution and their UV-Vis spectra. Possible interactions of fullerenes with the combining sites of IgG are discussed based on the physical chemistry of fullerenes and previously described protein-fullerene interactions. They remain to be confirmed by the isolation of mAbs for x-ray crystallographic studies.

Effect of topographical aspect and farm system on the population dynamics of Trichostrongylus larvae on a hill pasture

The population dynamics of Trichostrongylus colubriformis larvae were compared over two years on contrasting topographical aspects north (warm and dry) and south-facing (cool and moist) hill slopes) on paddocks which form part of the 'non-chemical' and conventional' farm systems at the AgResearch Ballantrae Hill Country Station located in a summer-moist region of New Zealand. Sheep faeces containing 50,000 Trichostrongylus eggs were incubated for 4 days at 25 degrees C and then deposited on each of 36 sub-plots in each of 8 plots in a 2 x 2 factorial design in the summer (summer trial) and again in autumn (autumn trial). Pasture was removed to ground level and larvae extracted from six sub-plots from each plot 2, 4, 6, 8, 11 and 14 weeks after contamination in all trials. Larvae were recovered from two strata, 0-5 cm above the soil surface and > 5 cm above the soil surface. Fewer (p < 0.001) larvae were recovered from herbage (47 vs. 118) and residual faeces (28 vs. 246) from the autumn than from the summer trials. This coincided with more rapid (p < 0.001) faecal disappearance in the autumn trials. In the summer trials, fewer (p < 0.003) larvae were recovered from the herbage (101 vs. 182) and residual faeces (140 vs. 352) from plots on the south than the north facing aspect. In the autumn trials there was a rapid (p < 0.0001) faecal disappearance from the south-facing aspect. In the autumn trials there was a non-significant (p < 0.10) trend for fewer larvae to be recovered from the south-facing aspect (2 vs. 54). This also coincided with more rapid faecal disappearance from the south-facing aspect. There was no effect of farm system on the number of larvae recovered. Despite greater (p < 0.0001) numbers of larvae recovered from the bottom stratum of herbage, the density of larvae (L3/kg DM) tended (p < 0.12) to be higher in the top stratum of herbage. It was concluded that season and aspect have a marked effect on the number of larvae recovered from herbage and that this was inversely related to the rate of faecal disappearance.

Analysis of Australian Crohn's disease pedigrees refines the localization for susceptibility to inflammatory bowel disease on chromosome 16

A number of localizations for the putative susceptibility gene(s) have been identified for both Crohn's disease and ulcerative colitis. In a genome wide scan, Hugot et al. (1996) identified a region on chromosome 16 which appeared to be responsible for the inheritance of inflammatory bowel disease in a small proportion of families. Subsequent work has suggested that this localization is important for susceptibility to Crohn's disease rather than ulcerative colitis (Ohmen et al. 1996; Parkes et al. 1996). We investigated the contribution of this localization to the inheritance of inflammatory bowel disease in 54 multiplex Australian families, and confirmed its importance in a significant proportion of Crohn's disease families; we further refined the localization to a region near to D16S409, obtaining a maximum LOD score of 6.3 between D16S409 and D16S753.

Gastrointestinal adenocarcinomas metastatic to the testes and associated structures in three dogs

Primary testicular neoplasms are common in dogs, but metastases to the testes are rare. Three dogs had enlargement of the testes and associated structures. Upon histological examination, the enlargements were due to metastatic adenocarcinomas. Further examination identified the gastrointestinal tract as the primary site of the metastatic neoplasms in all three cases. The testicular metastases reflected widespread metastatic disease. When metastatic adenocarcinoma is found in the testes and associated structures in dogs, the gastrointestinal tract should be examined closely for a primary tumor site.

Polymorphism of the Pi class glutathione S-transferase in normal populations and cancer patients

Deficiencies of the glutathione transferase isoenzymes GSTM1-1 and GSTT1-1 have been shown to be risk modifiers in a number of different cancers but there have been no similar studies with GSTP1-1, the only member of the Pi class of glutathione S-transferases expressed in humans. Over-expression of GSTP1-1 in tumours suggests that it may be a significant factor in acquired resistance to certain anticancer drugs. We previously identified a cDNA clone with two amino acid substitutions (I105V, A114V). This clone suggests that the GSTP1 gene is polymorphic and it is possible that the different genotypes may be associated with altered cancer risk or drug resistance. In the present study, we report methods for genotyping individuals at codons 105 and 114 of GSTP1 and demonstrate that these two loci are polymorphic in several different racial groups. We also detected significant linkage disequilibrium between these two loci. To determine if either of the alleles at these two loci were associated with altered cancer susceptibility, we genotyped individuals with colorectal cancer or lung cancer. A total of 131 colorectal and 184 lung cancer patients were compared with 199 control individuals. Overall, there were no significant associations between the GSTP1 polymorphisms and either form of cancer.

The Fresno Asthma Project: a model intervention to control asthma in multiethnic, low-income, inner-city communities

The Fresno Asthma Project targeted the entire low-income, inner-city, multiethnic population of Fresno, California. For 36 months following a 6-month planning phase, continuing education was provided to a high proportion of physicians, pharmacists, nurses/respiratory therapists, emergency medical technicians, school personnel, and allied health professionals involved in asthma care in Fresno, including virtually all those providing care/services to the target population. Small group patient education was made available and provided in age- and culturally appropriate formats to patients/families in clinics, hospitals, and schools. General and ethnic media and a Speakers Bureau were used to raise public awareness of asthma as a serious but controllable health problem. This community intervention model is particularly appropriate to multiethnic communities. It is relatively low cost (total direct costs were $140,000 per year), uses existing educational resources, and appears to have minimized counterproductive competition. Although morbidity and mortality trend data are not yet available to monitor program impact, penetration into the target community has been substantial: community physicians refer patients to asthma classes, asthma educator training is ongoing through the local American Lung Association chapter, hospitals and managed care systems serving low- income/MediCal patients offer asthma classes, and public schools and HeadStart are institutionalizing asthma awareness and self-management classes.

Uterine arteriovenous malformations: gray-scale and Doppler US features with MR imaging correlation

PURPOSE

To describe the gray-scale and color and duplex Doppler ultrasound (US) and the magnetic resonance (MR) imaging features of uterine arteriovenous malformations (AVMs).

MATERIALS AND METHODS

Uterine AVMs in 10 patients were retrospectively evaluated. All patients underwent gray-scale US and color and duplex Doppler US. Nine underwent angiography with therapeutic embolization; four, MR imaging. The resistance index (RI), pulsatility index (PI), and peak systolic velocities (PSVs) were evaluated.

RESULTS

At gray-scale US, uterine AVMs were nonspecific and manifested as subtle myometrial inhomogeneity, tubular spaces within the myometrium, intramural uterine mass, endometrial mass, or cervical mass or sometimes as prominent parametrial vessels. Color Doppler features were consistent and included intense juxtaposed signals with aliasing and apparent flow reversals. Spectral Doppler US revealed low-resistance flow (RI, 0.25-0.55; PI, 0.3-0.6) and PSVs greater than 96 cm/sec, which suggests arteriovenous shunting. MR imaging showed a bulky uterus, a focal uterine mass, disruption of the junctional zones, serpiginous flow-related signal voids, and prominent parametrial vessels.

CONCLUSION

Gray-scale morphology and Doppler US features should allow noninvasive diagnosis of uterine AVMs. Doppler and MR imaging features of uterine AVMs may overlap with other causes of arteriovenous shunting, including abnormal placentation and gestational trophoblastic disease (GTD). These can be differentiated with serum beta human chorionic gonadotropin test results (negative with AVM, positive with GTD).

Individual versus group education: is one better?

Individual and small group approaches to delivering patient education have differing potential advantages, and various criteria can be used to determine which is "better". Individualization of education is possible in either delivery format, as is its absence. Limited evidence regarding the relative effectiveness and cost-effectiveness of different delivery modes is available from direct comparison and meta-analyses of studies comparing either of the approaches with no education or the patient's own pre-education status. This evidence supports the conclusions that: (1) both individual and group education can improve patient outcomes, (2) it is not possible to conclude that the two delivery formats are essentially equivalent in effectiveness, and there is some evidence that group education may more effective for some outcomes, and (3) wide variation in effectiveness exists among programs in both delivery formats. A model continuum of asthma education is presented that takes advantage of the respective strengths of individual and group delivery.

Respiratory effects associated with indoor nitrogen dioxide exposure in children

BACKGROUND

The human health effects of exposure to indoor nitrogen dioxide (NO2) are unclear, and few studies have examined the effects of short-term peak levels of exposure.

METHODS

The association between indoor exposure to NO2 and respiratory illness was examined in 388 children aged 6-11 years. The NO2 levels were monitored during winter in 41 classrooms, from four schools with unflued gas heating and four schools with electric heating. Each classroom was monitored daily with 6-hour passive diffusion badge monitors over nine alternate weeks, and with hourly monitors over two of those weeks. Children living in homes with unflued gas appliances were also monitored daily over four evenings during times of gas use.

RESULTS

Exposure to NO2 at hourly peak levels of the order of > or = 80 ppb, compared with background levels of 20 ppb, was associated with a significant increase in sore throat, colds and absences from school. An increase in cough with phlegm was marginally significant. Significant dose-response relationships were demonstrated for these four measures with increasing levels of NO2 exposure.

CONCLUSIONS

Short-term peak levels of exposure are important to consider in relation to adverse respiratory effects associated with NO2 exposure.

Introduction of an ultrasound picture archiving and communication system: experience in the first year

OBJECTIVE

To describe the authors' first year's experience with a picture archiving and communication system (PACS) for the management and storage of ultrasound images and to discuss the financial impact of the system in terms of costs of purchase, installation and operation.

MATERIALS AND METHODS

The Toronto Hospital, General Division, performs more than 30000 ultrasound studies each year. On June 27, 1994, an Ultra PACS (ALI Technology Incorporated, Richmond, BC) was introduced as the only method of image storage and archiving in the Ultrasound Division.

RESULTS

After structural renovations and a detailed work flow analysis, the Ultrasound Division converted from film to the PACS over a single weekend with no back-up. The advantages to date include consistently high-quality images; rapid image retrieval (images from the same day [online], 0 to 45 seconds; archived images [online], 3 to 5 minutes; images in storage [offline], 3 minutes); no loss of images; more efficient patient through-put, which allows the division to handle the same number of patients in 20% less operational time (change from a 10-hour day to an 8-hour day, over a 5-day week); less end-of-day overtime; and an improved work environment. There has been no change in the division's complement of full-time equivalent technologists, the number of film librarians has been reduced by 1, and physician service time has decreased by 20%. There has been no significant impact on overall operational financial status.

CONCLUSION

The PACS has proved an efficient method for managing large numbers of ultrasound images in a cost-effective and technically sound manner. Its installation provides the basis for meeting the Ultrasound Division's next objective, to eliminate paper as the primary method of managing patient information and reports.

The partition matrix: exploring variable phylogenetic signals along nucleotide sequence alignments

The partition matrix is a graphical tool for comparative analysis of nucleotide sequences following alignment. It is particularly useful for investigating the divergent phylogenies of sequence regions undergoing reticulate evolution. A partition matrix is generated by determining the consistency of the parsimoniously informative sites in a set of aligned sequences with the binary partitions inferred from the sequences. Since the linear order of sites is maintained, the matrix can be used to assess whether the distribution of sites either supporting or conflicting with particular partitions changes along the length of the alignment. The usefulness of the matrix in allowing visual identification of differences in evolutionary history among regions depends on the order in which partitions are shown; several suitable ordering schemes are proposed. We demonstrate the use of the partition matrix in interpreting the evolution of the pseudoautosomal boundary region on the sex chromosome of catarrhine primates. Its routine use should help to avoid attempts to derive single phylogenies from sequences whose evolution has been reticulate and to identify the gene conversion or recombination events underlying the reticulation. The method is relatively fast. It is exploratory, and it can form the basis for more formal analysis, which we discuss.

On extending the transmission/disequilibrium test (TDT)

The transmission/disequilibrium test (TDT), for evaluation of the null hypothesis of neither linkage nor association between a marker locus and disease, is extended to the more general situation of transmission of two multi-allele marker loci from parents to affected offspring. Transmission probabilities are derived for a generalized single locus disease model, where the disease locus is taken to lie between the two marker loci. There could be unlinked modifier loci for the disease. Examples of the extended TDT are given and it is shown how the contribution from each locus can be evaluated, both separately and jointly.

Bridging language and cultural barriers between physicians and patients

OBJECTIVE

This study explored a group of primary care physicians' use of various methods to bridge language and cultural barriers between themselves and their patients and the physicians' perceptions of the availability and quality of these methods.

METHODS

The authors mailed a questionnaire to 495 primary care physicians in the Greater Bay Area of northern California, an area chosen for its ethnically diverse population. Respondents were asked to estimate how many patients they saw per week, how many encounters they had per week with non-English-speaking patients, and how often they used each of six interpretation methods. They were also asked to assess the availability and quality of interpretation services.

RESULTS

Physicians reported that, on average, 21% of visits were with non-English-speaking patients. Trained medical interpreters or the AT&T Language Line were used, on average, in fewer than 6% of these encounters, and no interpreters were used in 11%. In 27% of encounters with non-English-speaking patients, the physician could speak the patient's language, in 20% interpretation was done by a staff member who had no formal interpretation training, and in 36% a family member or companion of the patient interpreted. Physicians who had access to trained interpreters reported a significantly higher quality of patient-physician communication than physicians who used other methods (P < 0.0001).

CONCLUSIONS

In an area of great ethnic diversity where physicians who had access to the services of trained interpreters reported a significantly higher quality of patient-physician communication, the low rates of use of trained interpreters suggest that factors other than quality, such as costs, preclude greater use of these services.

Abdominal sonography in asymptomatic executives: prevalence of pathologic findings, potential benefits, and problems

Abdominal ultrasonography was performed on 1000 asymptomatic executives over a period of 6 months as part of a comprehensive health examination. The use of ultrasonography in these persons was evaluated with regard to the prevalence and variety of pathologic conditions detected as well as potential benefits, risks, and use as a screening tool. Significant sonographic diagnoses included renal cell carcinoma in four patients (0.4%) and abdominal aortic aneurysm in four patients (0.4%). Abdominal sonography performed on 7925 asymptomatic executives over a subsequent 2 1/2 year period led to detection of 23 (0.3%) additional renal cell carcinomas. The prevalence of renal cell carcinoma in this population is substantially greater than that of the general population. Abdominal sonography facilitates detection of occult renal neoplasms and aortic aneurysms. The cost effectiveness and potential use of sonography as a screening tool remains to be determined, however, given the relatively low overall prevalence of these pathologic conditions.

Intraoperative end-tidal carbon dioxide levels and derived calculations correlated with outcome in trauma patients

BACKGROUND

To determine the relationship between the prognosis of seriously injured patients requiring emergency surgery and intraoperative end-tidal CO2 variables and "excess Pco2."

METHOD

Retrospective chart review of 100 seriously injured patients admitted to Detroit Receiving Hospital and requiring major surgery (mortality rate of 40%). Standard intraoperative monitoring, including continuous capnography, plus arterial blood analyses every 15 to 30 minutes during surgery.

RESULTS

After resuscitation for 45 to 90 minutes, 11 patients had a systolic blood pressure < 100 mm Hg and, of these patients, 10 (91%) died. Of the remaining 89 patients, mortality rates were 53% (16/30), with an end-tidal CO2 of 22 mm Hg or less, versus 24% (14/59) with an end-tidal CO2 of 23 mm Hg or more (p = 0.011). An arterial to end-tidal Pco2 difference of 13 mm Hg or more after resuscitation was associated with an increased mortality rate (50% (20/34 vs. 18% (20/55)) (p < 0.005). The mortality rate was particularly high, with a final arterial to end-tidal Pco2 difference of 12 mm Hg or more (73% (30/41) versus 17% (10/59) (p < 0.001). A final Paco2 excess (i.e., the amount by which the Paco2 was higher than expected from the bicarbonate) > 1.0 mm Hg was also associated with an increased mortality rate ((62% (33/53) vs. 15% (7/47)) (p < 0.001).

CONCLUSION

Values derived from the end-tidal CO2 and the excess Pco2 should be monitored intraoperatively in critically injured patients. Efforts should be made to improve cardiac output and adjust ventilation to maintain an end-tidal Pco2 of 25 mm Hg or more, an arterial to end-tidal CO2 difference of 12 mm Hg or less, and an excess Paco2 of 1.0 mm Hg or less.

Patients' perceptions compared with objective ratings of asthma severity

BACKGROUND

Optimal asthma management requires accurate assessment of asthma severity.

OBJECTIVE

To compare patients' perceptions of their asthma severity with that obtained by using the guidelines published by the National Asthma Education and Prevention Program's Expert Panel and with functional impairment measured by spirometry and numeric criteria of the American Thoracic Society.

METHODS

We enrolled 323 patients age 18 to 50 years who were members of the Kaiser Foundation Health Plan for > or = 1 year in a randomized control trial of an asthma education program. Each had a confirmed diagnosis of bronchial asthma and had been receiving antiasthma medication for > or = 1 year. Patients rated the severity of their asthma. Office spirometry was performed, and, using the Mini-Wright peak flow meter, patients kept 2-week diaries of at-home recordings of morning and evening peak expiratory flow rates.

RESULTS

A statistically significant association was noted between patients' perceptions of asthma severity and both medication severity rating (P < .001) and diurnal variation rating (P = .003) and evening peak expiratory flow rate percentage (P = .019). In comparison with a severity composite based on criteria of the National Asthma Education Program, 54% of patients accurately estimated asthma severity, 27% overestimated, and 20% underestimated severity.

CONCLUSION

A clinically significant proportion of asthmatic patients substantially underestimate disease severity and thereby may be at risk of increased mortality or morbidity.

Biological applications of fullerenes

Thus far, development of applications of fullerenes in biology has been hampered by the poor water solubility of fullerenes. In spite of such concerns, fullerenes have proved useful for a wide variety of biological applications. As derivatized and underivatized fullerenes continue to become increasingly available, additional applications and further development of those discussed in this article will invariably follow.

Manifestations of Crohn disease at US

Crohn disease is a chronic inflammatory disorder of the intestines that is characterized by multiple episodes of exacerbation and remission. Although barium studies and endoscopy remain the most valuable tools for assessment of mucosal and luminal changes, sonography has proved to be a safe and noninvasive modality for characterization of mural and perienteric changes. Ultrasonography (US) can accurately demonstrate the classic features of Crohn disease as well as the complications frequently associated with the disease. The addition of color Doppler imaging may allow differentiation of chronic from active bowel wall thickening. In expert hands, US appears to be a sensitive modality for preliminary investigation of patients with symptomatic Crohn disease. US can also be used to assess the response to treatment and to detect postoperative recurrence. Finally, US enables accurate selection of patients in whom the possibility of surgery or percutaneous intervention would justify other means of investigation, particularly computed tomography.

Lipiodol accumulation in hepatic hemangioma. Detection with osmium postfixation

Lipiodol has been used to increase the detectability of small primary neoplasms in the liver. We report a patient who was found to have lipiodol deposits in the liver one month after intra-arterial injection. The region was resected, under ultrasound control, because of the impression that the lesion was malignant. The specimen contained two small hemangiomas as well as many small dysplastic nodules (adenomatous hyperplasia) in a noncirrhotic parenchyma. To locate the lipiodol deposit in this case, the tissue was radiographed, postfixed in osmium tetroxide, and embedded in paraffin. Black osmium-stained deposits were found within the cavities of the hemangiomas but not in the dysplastic nodules. Most of the deposits were extracellular multivesiculated bodies with a small focus of lipid droplets engulfed by multinucleated foreign-body type giant cells. This report reinforces that hepatic lipiodol retention is not specific for hepatocellular carcinoma. We present, for the first time, the histologic appearance of lipiodol accumulation in an hemangioma. The value of osmium tetroxide postfixation for the detection of lipiodol is also demonstrated.

An education program for parents of children with asthma: differences in attendance between smoking and nonsmoking parents

We studied smoking status in relation to parental attendance at an asthma education program for child patients of a health maintenance organization. Nonattendance rates were 24%, 42%, and 78% in nonsmoking, one-smoker, and two-or-more-smoker families, respectively, and 33% overall. Only the number of smokers (odds ratio [OR] = 3.1; 95% confidence interval [CI] = 1.8, 5.3) and perceived adverse impact of asthma on the family (OR = 0.4; 95% CI = 0.2, 0.9) were retained in a multivariate model that correctly classified 73% of families; demographic characteristics, frequency of asthma symptoms, and health care use were rejected. There was a tendency for smoking parents to deny that their child had asthma (17% among families with two or more smokers; 9% among nonsmoking families). Asthma education programs may fail to involve parents who smoke.

Education of parents of infants and very young children with asthma: a developmental evaluation of the Wee Wheezers program

A randomized control trial of the Wee Wheezers asthma education program was conducted with 76 children < 7 years of age, 31% of whom were on a medication regimen consistent with mild, 51% with moderate, and 18% with moderately severe/severe asthma. Treatment children showed improved morbidity at 3-month follow-up relative to the changes in the controls: increased symptom-free days in the preceding 2 weeks (mean change of +2.2 vs. -2.6 in the controls; p = .004) and month (+2.0 vs. -3.8; p < .02), fewer nights of parental sleep interruption in a typical week (+0.7 vs. +1.8; p < or = .05), and a trend toward fewer asthma sick days (-0.2 vs +0.7; p = ns). These improvements were accompanied by significantly better parental asthma management compared with controls (more consistent use of preventive medications, p < or = .01; early symptom intervention, [corrected] p < or = .05) and trends toward more restrictions on smoking in the home (p < .07) and decreased parental confusion about asthma treatment (p < .11). This study provides evidence that a multisession program of asthma education for parents can improve parental asthma management and clinical outcomes in very young children and provides information on the validity and sensitivity of various asthma outcome measures in this age group.