Determining predictive metabolomic biomarkers of meniscal injury in dogs with cranial cruciate ligament rupture

OBJECTIVES

This study used hydrogen nuclear magnetic resonance spectroscopy for the first time to examine differences in the metabolomic profile of stifle joint synovial fluid from dogs with cranial cruciate ligament rupture with and without meniscal injuries, in order to identify biomarkers of meniscal injury. Identifying a biomarker of meniscal injury could then ultimately be used to design a minimally invasive diagnostic test for meniscal injuries in dogs.

MATERIALS AND METHODS

Stifle joint synovial fluid was collected from dogs undergoing stifle joint surgery or arthrocentesis for lameness investigations. We used multi-variate statistical analysis using principal component analysis and univariate statistical analysis using one-way analysis of variance and analysis of co-variance to identify differences in the metabolomic profile between dogs with cranial cruciate ligament rupture and meniscal injury, cranial cruciate ligament rupture without meniscal injury, and neither cranial cruciate ligament rupture nor meniscal injury, taking into consideration clinical variables.

RESULTS

A total of 154 samples of canine synovial fluid were included in the study. Sixty-four metabolites were annotated to the hydrogen nuclear magnetic resonance spectroscopy spectra. Six spectral regions were found to be significantly altered (false discovery rate adjusted P-value <0.05) between groups with cranial cruciate ligament rupture with and without meniscal injury, including three attributed to nuclear magnetic resonance mobile lipids [mobile lipid -CH3 (P=0.016), mobile lipid -n(CH3 )3 (P=0.017), mobile unsaturated lipid (P=0.031)].

CLINICAL SIGNIFICANCE

We identified an increase in nuclear magnetic resonance mobile lipids in the synovial fluid of dogs with meniscal injury which are of interest as potential biomarkers of meniscal injury.

Characterization of the public transit air microbiome and resistome reveals geographical specificity

BACKGROUND

The public transit is a built environment with high occupant density across the globe, and identifying factors shaping public transit air microbiomes will help design strategies to minimize the transmission of pathogens. However, the majority of microbiome works dedicated to the public transit air are limited to amplicon sequencing, and our knowledge regarding the functional potentials and the repertoire of resistance genes (i.e. resistome) is limited. Furthermore, current air microbiome investigations on public transit systems are focused on single cities, and a multi-city assessment of the public transit air microbiome will allow a greater understanding of whether and how broad environmental, building, and anthropogenic factors shape the public transit air microbiome in an international scale. Therefore, in this study, the public transit air microbiomes and resistomes of six cities across three continents (Denver, Hong Kong, London, New York City, Oslo, Stockholm) were characterized.

RESULTS

City was the sole factor associated with public transit air microbiome differences, with diverse taxa identified as drivers for geography-associated functional potentials, concomitant with geographical differences in species- and strain-level inferred growth profiles. Related bacterial strains differed among cities in genes encoding resistance, transposase, and other functions. Sourcetracking estimated that human skin, soil, and wastewater were major presumptive resistome sources of public transit air, and adjacent public transit surfaces may also be considered presumptive sources. Large proportions of detected resistance genes were co-located with mobile genetic elements including plasmids. Biosynthetic gene clusters and city-unique coding sequences were found in the metagenome-assembled genomes.

CONCLUSIONS

Overall, geographical specificity transcends multiple aspects of the public transit air microbiome, and future efforts on a global scale are warranted to increase our understanding of factors shaping the microbiome of this unique built environment.

Identification of tissue-dependent proteins in knee OA synovial fluid

OBJECTIVE

For many proteins from osteoarthritic synovial fluid, their intra-articular tissue of origin remains unknown. In this study we performed comparative proteomics to identify osteoarthritis-specific and joint tissue-dependent secreted proteins that may serve as candidates for osteoarthritis biomarker development on a tissue-specific basis.

DESIGN

Protein secretomes of cartilage, synovium, Hoffa's fat pad and meniscus from knee osteoarthritis patients were determined using liquid chromatography tandem mass spectrometry, followed by label-free quantification. Validation of tissue-dependent protein species was conducted by ELISA on independent samples. Differential proteomes of osteoarthritic and non-osteoarthritic knee synovial fluids were obtained via similar proteomics approach, followed by ELISA validation.

RESULTS

Proteomics revealed 64 proteins highly secreted from cartilage, 94 from synovium, 37 from Hoffa's fat pad and 21 from meniscus. Proteomic analyses of osteoarthritic vs non-osteoarthritic knee synovial fluid revealed 70 proteins with a relatively higher abundance and 264 proteins with a relatively lower abundance in osteoarthritic synovial fluid. Of the 70 higher abundance proteins, 23 were amongst the most highly expressed in the secretomes of a specific intra-articular tissue measured. Tissue-dependent release was validated for SLPI, C8, CLU, FN1, RARRES2, MATN3, MMP3 and TNC. Abundance in synovial fluid of tissue-dependent proteins was validated for IGF2, AHSG, FN1, CFB, KNG and C8.

CONCLUSIONS

We identified proteins with a tissue-dependent release from intra-articular human knee OA tissues. A number of these proteins also had an osteoarthritis-specific abundance in knee synovial fluid. These proteins may serve as novel candidates for osteoarthritis biomarker development on a tissue-specific basis.

PM2.5 on the London Underground

INTRODUCTION

Despite the London Underground (LU) handling on average 2.8 million passenger journeys per day, the characteristics and potential health effects of the elevated concentrations of metal-rich PM2.5 found in this subway system are not well understood.

METHODS

Spatial monitoring campaigns were carried out to characterise the health-relevant chemical and physical properties of PM2.5 across the LU network, including diurnal and day-to-day variability and spatial distribution (above ground, depth below ground and subway line). Population-weighted station PM2.5 rankings were produced to understand the relative importance of concentrations at different stations and on different lines.

RESULTS

The PM2.5 mass in the LU (mean 88 μg m-3, median 28 μg m-3) was greater than at ambient background locations (mean 19 μg m-3, median 14 μg m-3) and roadside environments in central London (mean 22 μg m-3, median 14 μg m-3). Concentrations varied between lines and locations, with the deepest and shallowest submerged lines being the District (median 4 μg m-3) and Victoria (median 361 μg m-3 but up to 885 μg m-3). Broadly in agreement with other subway systems around the world, sampled LU PM2.5 comprised 47% iron oxide, 7% elemental carbon, 11% organic carbon, and 14% metallic and mineral oxides. Although a relationship between line depth and air quality inside the tube trains was evident, there were clear influences relating to the distance from cleaner outside air and the exchange with cabin air when the doors open. The passenger population-weighted exposure analysis demonstrated a method to identify stations that should be prioritised for remediation to improve air quality.

CONCLUSION

PM2.5 concentrations in the LU are many times higher than in other London transport Environments. Failure to include this environment in epidemiological studies of the relationship between PM2.5 and health in London is therefore likely to lead to a large exposure misclassification error. Given the significant contribution of underground PM2.5 to daily exposure, and the differences in composition compared to urban PM2.5, there is a clear need for well-designed studies to better understand the health effects of underground exposure.

Uranium Transport and the Partitioning of U, Th, and Ra Isotopes Between Solid and Aqueous Phases in the Krunkelbach Mine, Federal Republic of Germany

This paper discusses some of the results from a natural geochemical analogue study on the Krunkelbach mine, F.R.G. These data, based largely on uranium series disequilibrium measurements, are used to compare the results of groundwater modelling programmes with observations made in the mine.

How contraceptive use patterns differ by pregnancy intention: implications for counseling

To increase awareness of issues to include in contraceptive counseling-the objectives of this study were to evaluate: 1) how contraceptive use patterns (eg, non-use), level of effectiveness of contraceptive method, and sociodemographic characteristics may be associated with the occurrence of unintended pregnancy; 2) patterns of health care use for women with intended and unintended pregnancy; and 3) the association between contraceptive use patterns and sociodemographic characteristics. In-person interviews were conducted with 279 women enrolled in a Medicaid managed care health plan who had been pregnant in the last 5 years. Self-reported measures of pregnancy intention, contraceptive use, and health care use were collected. The relationships of pregnancy intention with contraceptive use patterns, level of effectiveness of contraceptive method used, and patterns of recent health care use were assessed. Differences in contraceptive use patterns by sociodemographic groups were assessed. Seventy-eight percent of women reported an unintended pregnancy. Non-use of birth control the month before conception was reported by 57% of women with unintended pregnancies and 84% of women with intended pregnancies. Use of birth control of low effectiveness was reported by 20% of women with unintended pregnancies and 8% of women with intended pregnancies. Non-use or use of contraceptive methods of low effectiveness did not differ for women in different sociodemographic groups regardless of pregnancy intention status. A majority of women reported recent health care use. Health care providers should be aware that women who have no intention for pregnancy may not be using an effective contraceptive method NOR have an effective pattern of contraceptive use.

Physician incentives and disclosure of payment methods to patients

OBJECTIVE

There is increasing public discussion of the value of disclosing how physicians are paid. However, little is known about patients' awareness of and interest in physician payment information or its potential impact on patients' evaluation of their care.

DESIGN

Cross-sectional survey

SETTING

Managed care and indemnity plans of a large, national health insurer.

PARTICIPANTS

Telephone interviews were conducted with 2,086 adult patients in Atlanta, Ga; Baltimore, Md/Washington DC; and Orlando, Fla (response rate, 54%).

MEASUREMENTS AND MAIN RESULTS

Patients were interviewed to assess perceptions of their physicians' payment method, preference for disclosure, and perceived effect of different financial incentives on quality of care. Non-managed fee-for-service patients (44%) were more likely to correctly identify how their physicians were paid than those with salaried (32%) or capitated (16%) physicians. Just over half (54%) wanted to be informed about their physicians' payment

METHOD

Patients of capitated and salaried physicians were as likely to want disclosure as patients of fee-for-service physicians. College graduates were more likely to prefer disclosure than other patients. Many patients (76%) thought a bonus paid for ordering fewer than the average number of tests would adversely affect the quality of their care. About half of the patients (53%) thought a particular type of withhold would adversely affect the quality of their care. White patients, college graduates, and those who had higher incomes were more likely to think that these types of bonuses and withholds would have a negative impact on their care. Among patients who believed that these types of bonuses adversely affected care, those with non-managed fee-for-service insurance and college graduates were more willing to pay a higher deductible or co-payment in order to get tests that they thought were necessary.

CONCLUSIONS

Most patients were unaware of how their physicians are paid, and only about half wanted to know. Most believed that bonuses or withholds designed to reduce the use of services would adversely affect the quality of their care. Lack of knowledge combined with strong attitudes about various financial incentives suggest that improved patient education could clarify patient understanding of the nature and rationale for different types of incentives. More public discussion of this important topic is warranted.

Prenatal care in the first trimester: misleading findings from HEDIS. Health Plan Employer Data and Information Set

OBJECTIVE

To understand factors influencing Health Plan Employer Data and Information Set (HEDIS) rates for the measure 'Prenatal care in the first trimester'.

DESIGN

Telephone survey of a retrospective cohort of women with a live birth. Medical record review of a sample of both responders and non-responders to the telephone survey. Detailed review of HEDIS data collection procedures.

SETTING

A managed care plan in California.

STUDY PARTICIPANTS

Women aged 18-49 years at date of delivery, who delivered a live birth from 1 October 1995 through 31 March 1996, and who were continuously enrolled in a California managed care plan for 12 months prior to delivery (telephone survey, n= 1,185; medical record review, n= 465).

RESULTS

Of the women participating in the telephone survey, 95% indicated that their first prenatal visit occurred during the first 3 months of pregnancy. Using HEDIS 3.0 standards, a review of medical records for a sample of these women indicated that 94% of the women initiated care during the first trimester. These results contrasted sharply with 1995 and 1996 HEDIS rates of 64% and 75%, respectively.

CONCLUSION

An investigation of the discrepancy between HEDIS rates and rates from both telephone survey and medical record review led to the finding that the low HEDIS rates were due not to a true low rate of early care, but to data collection problems, including difficulty obtaining medical records. Potential solutions involving health plan activities, revisions to the official HEDIS process and revised reporting of results are proposed.

Health literacy among Medicare enrollees in a managed care organization

CONTEXT

Elderly patients may have limited ability to read and comprehend medical information pertinent to their health.

OBJECTIVE

To determine the prevalence of low functional health literacy among community-dwelling Medicare enrollees in a national managed care organization.

DESIGN

Cross-sectional survey.

SETTING

Four Prudential HealthCare plans (Cleveland, Ohio; Houston, Tex; south Florida; Tampa, Fla).

PARTICIPANTS

A total of 3260 new Medicare enrollees aged 65 years or older were interviewed in person between June and December 1997 (853 in Cleveland, 498 in Houston, 975 in south Florida, 934 in Tampa); 2956 spoke English and 304 spoke Spanish as their native language. MAIN OUTCOME MEASURE; Functional health literacy as measured by the Short Test of Functional Health Literacy in Adults.

RESULTS

Overall, 33.9% of English-speaking and 53.9% of Spanish-speaking respondents had inadequate or marginal health literacy. The prevalence of inadequate or marginal functional health literacy among English speakers ranged from 26.8% to 44.0%. In multivariate analysis, study location, race/language, age, years of school completed, occupation, and cognitive impairment were significantly associated with inadequate or marginal literacy. Reading ability declined dramatically with age, even after adjusting for years of school completed and cognitive impairment. The adjusted odds ratio for having inadequate or marginal health literacy was 8.62 (95% confidence interval, 5.55-13.38) for enrollees aged 85 years or older compared with individuals aged 65 to 69 years.

CONCLUSIONS

Elderly managed care enrollees may not have the literacy skills necessary to function adequately in the health care environment. Low health literacy may impair elderly patients' understanding of health messages and limit their ability to care for their medical problems.

The relationship between method of physician payment and patient trust

CONTEXT

Trust is the cornerstone of the patient-physician relationship. Payment methods that place physicians at financial risk have raised concerns about patients' trust in physicians to act in patients' best interests.

OBJECTIVE

To evaluate the extent to which methods of physician payment are related to patient trust.

DESIGN

Cross-sectional telephone interview survey done between January and June 1997.

SETTING

Health plans of a large national insurer in Atlanta, Ga, the Baltimore, Md-Washington, DC, area, and Orlando, Fla.

PARTICIPANTS

A total of 2086 adult managed care and indemnity patients.

MAIN OUTCOME MEASURE

A 10-item scale (alpha = .94) assessing patients' trust in physicians.

RESULTS

More fee-for-service (FFS) indemnity patients (94%) completely or mostly trust their physicians to "put their health and well-being above keeping down the health plan's costs" than salary (77%), capitated (83%), or FFS managed care patients (85%) (P<.001 for pairwise comparisons). In multivariate analyses that adjusted for potentially confounding factors, FFS indemnity patients also had higher scores on the 10-item trust scale than salary (P<.001), capitated (P<.001), or FFS managed care patients (P<.01). The effects of payment method on patient trust were reduced when a measure based on patients' reports about physician behavior (eg, Does your physician take enough time to answer your questions?) was included in the regression analyses, but the differences remained statistically significant, except for the comparison between FFS managed care and FFS indemnity patients (P=.08). Patients' perceptions of how their physicians were paid were not independently associated with trust, but the 37.7% who said they did not know how their physicians were paid had higher levels of trust than other patients (P<.01). A total of 30.2% of patients were incorrect about their physicians' method of payment.

CONCLUSIONS

Most patients trusted their physicians, but FFS indemnity patients have higher levels of trust than salary, capitated, or FFS managed care patients. Patients' reports of physician behavior accounted for part of the variation in patients' trust in physicians who are paid differently. The impact of payment methods on patient trust may be mediated partly by physician behavior.

Patients' trust in their physicians: effects of choice, continuity, and payment method

OBJECTIVE

To evaluate the extent to which physician choice, length of patient-physician relationship, and perceived physician payment method predict patients' trust in their physician.

DESIGN

Survey of patients of physicians in Atlanta, Georgia.

PATIENTS

Subjects were 292 patients aged 18 years and older.

MEASUREMENTS AND MAIN RESULTS

Scale of patients' trust in their physician was the main outcome measure. Most patients completely trusted their physicians "to put their needs above all other considerations" (69%). Patients who reported having enough choice of physician (p < .05), a longer relationship with the physician (p < .001), and who trusted their managed care organization (p < .001) were more likely to trust their physician. Approximately two thirds of all respondents did not know the method by which their physician was paid. The majority of patients believed paying a physician each time a test is done rather than a fixed monthly amount would not affect their care (72.4%). However, 40.5% of all respondents believed paying a physician more for ordering fewer than the average number of tests would make their care worse. Of these patients, 53.3% would accept higher copayments to obtain necessary medical tests.

CONCLUSIONS

Patients' trust in their physician is related to having a choice of physicians, having a longer relationship with their physician, and trusting their managed care organization. Most patients are unaware of their physician's payment method, but many are concerned about payment methods that might discourage medical use.

Are we underestimating rates of vaginal birth after previous cesarean birth? The validity of delivery methods from birth certificates

Previous studies of birth certificates have not fully evaluated how accurately they identify delivery methods that have a historical component, such as repeat cesarean and vaginal birth after previous cesarean (VBAC). The authors used linked Georgia birth certificates for first and second deliveries to examine the accuracy of four reported delivery methods in the second pregnancy: vaginal (without previous cesarean), VBAC, primary cesarean, and repeat cesarean, as well as an indicator of a previous cesarean. From the immediate birth certificates, the delivery method for each of the two births was classified as vaginal (V) or cesarean section (CS), which produced possible sequences of V-V, CS-V, V-CS, and CS-CS. The delivery method for the second births to 106,049 women from 1989 through 1992 was reviewed, taking into account the historical information from the linked certificates regarding the first births. Only 42.0% of women with a CS-V sequence were correctly designated on the second birth certificate as a VBAC; 79.3% of women with a V- CS sequence were correctly designated as primary cesarean. From 1980 through 1988, birth certificates contained a check box indicating a previous cesarean (but no VBAC box). During this period, only 75.5% of 25,491 women with a previous cesarean were so designated on the birth certificate. These findings suggest that cross-sectional vital records data substantially underestimate VBAC and primary cesarean rates.

The effect of gas density on glottal vibration and exit jet particle velocity

Although theoretical studies include a term for gas density in their mathematical descriptions of glottal aerodynamics, the effect of gas density on glottal vibration has not been examined empirically. In this study, an in vivo canine model was used to evaluate the effect of gas density on glottal vibration by comparing phonation with air and helium. With gas flow and nerve stimulation held constant, phonation with helium resulted in an increased exit jet particle velocity for helium (45 m/s) compared to air (34 m/s). However, the measured increase in helium velocity was less than predicted by a proportional relationship between transglottal pressure and dynamic pressure. This difference could be due to a change in the constant of proportionality or in the dynamic pressure loss coefficient associated with the use of helium.

Changes in glottal area associated with increasing airflow

Laryngeal resistance varies inversely with airflow during phonation. This study evaluated the morphological changes in the glottis that accompany decreases in laryngeal resistance at higher levels of airflow. An in vivo canine model of phonation and a video analysis system were used to assess changes in area. Four animals were examined stroboscopically as airflow increased, with constant recurrent laryngeal nerve stimulation. Glottal dynamics were evaluated by means of photoglottography, electroglottography, and measures of subglottic pressure. Analysis of digitized stroboscopic images indicated that increasing airflow had no obvious effect on the glottal chink (vocal process contact). Increasing airflow was associated with an increase in the area of peak opening and an increase in the glottal area integral.

Effect of tension, stiffness, and airflow on laryngeal resistance in the in vivo canine model

This study used an in vivo canine model of phonation to determine the effects of airflow on glottal resistance at low, medium, and high levels of recurrent laryngeal nerve (RLN) and superior laryngeal nerve (SLN) stimulation. Static and dynamic trials of changing airflow were used to study the effects of airflow on glottal resistance during phonation. As reported previously, glottal resistance varies inversely as a function of airflow. Increasing levels of RLN stimulation resulted in a statistically significant increase in glottal resistance for each level of airflow evaluated. Variation in SLN stimulation had no statistically effects on the relationship between flow and resistance. At airflow rates greater than 590 milliliters per second (mL/s), glottal resistance approached 0.1 mm Hg per mL/s for all levels of RLN and SLN stimulation tested. These data support the collapsible tube model of phonation.

Point-touch technique of botulinum toxin injection for the treatment of spasmodic dysphonia

Intralaryngeal injections of botulinum toxin (Botox), under electromyographic guidance, have emerged as an effective treatment for adductor spasmodic dysphonia. To remain effective, these injections must be repeated every 3 to 9 months as the symptoms recur. One drawback to the current method is the need for electromyographic confirmation of needle placement into the thyroarytenoid muscle. This report describes an anatomic approach to Botox injection that requires only flexible nasopharyngeal endoscopy and careful evaluation of the anatomic landmarks. This technique has been used successfully on 13 patients, and objective pretreatment and posttreatment measures are reported.

Physiologic motion after vocal cord reinnervation: a preliminary study

This study attempted to reestablish physiologic vocal cord motion, rather than synkinesis, to a reinnervated vocal cord. One mongrel dog underwent a division and reanastomosis of the anterior branch of the right recurrent laryngeal nerve and simultaneous separation and reimplantation of a posterior division nerve-muscle pedicle into the posterior cricoarytenoid muscle. After 21 weeks, spontaneous physiologic vocal cord movement and electromyographic (EMG) activity were recorded during respiratory obstruction and laryngeal mechanical stimulation. Acoustic measures and histologic data are also presented from the reinnervated and normal vocalis muscle and from the recurrent laryngeal nerve. This study demonstrated that physiologic vocal cord motion can be achieved after laryngeal reinnervation using this technique.

Vocal fold medialization by surgical augmentation versus arytenoid adduction in the in vivo canine model

There are a variety of methods for treating unilateral vocal cord paralysis, but to date there have been few studies that compare these phonosurgical techniques by using objective measures of voice improvement. Vocal efficiency is an objective voice measure that is defined as the ratio of the acoustic power produced by the larynx to the subglottic air power. Vocal efficiency has been found to decrease with glottic disorders such as vocal cord paralysis and carcinoma. This study compared the effects of vocal fold medialization by surgical augmentation to those of arytenoid adduction on the vocal efficiency, videostroboscopy, and acoustics (jitter, shimmer, and signal-to-noise ratio) of a simulated unilateral vocal cord paralysis in an in vivo canine model. Arytenoid adduction was superior to surgical augmentation in vocal efficiency, traveling wave motion, and acoustics.

A functional evaluation of ansa cervicalis nerve transfer for unilateral vocal cord paralysis: future directions for laryngeal reinnervation

There are a variety of methods for treating unilateral vocal cord paralysis, but to date there are few objective studies that evaluate the functional results of nerve transfer from the ansa cervicalis. Six dogs underwent unilateral recurrent laryngeal nerve section with immediate reanastamosis to the sternothyroid branch of the ansa cervicalis. After 5 to 6 months, measurements of vocal efficiency and acoustic parameters, videolaryngoscopy, videostroboscopy, and evoked electromyography were performed. Identical measurements were made in eight control dogs during normal electrically induced phonation and a simulated unilateral recurrent laryngeal nerve paralysis. Histologic analysis of both vocalis muscles, recurrent laryngeal nerves, ansa cervicalis, and the ansa-recurrent laryngeal nerve anastamosis site was performed. Evidence of reinnervation was found in all of the animals that underwent nerve transfer. The vocal efficiency and acoustic quality after ansa cervicalis nerve transfer were dependent on the degree of electrical stimulation from the transferred nerve to the reinnervated cord during phonation. In the absence of electrical stimulation to the nerve transfer, physiologic vocal cord motion could not be elicited from the reinnervated cord.

An in vivo canine model for testing treatment effects in laryngeal hyperadduction disorders

Adductor spastic dysphonia is a voice disorder characterized by a strained, squeezed, effortful voice produced by true and false cord hyperadduction. An in vivo canine model has been developed to simulate hyperadduction of the true cords. Using this model, the thyroarytenoid muscle was found to have a greater effect on intraglottic and subglottic pressure than cricothyroid muscle contraction. The intraglottic and subglottic pressure was reduced after simulated recurrent laryngeal paralysis. This model can be used in future studies to compare laryngeal treatment modalities for disorders that have a component of vocal cord hyperadduction, such as spastic dysphonia.

Surgical management of lung cancer with solitary cerebral metastasis

Between 1964 and 1986, 19 patients underwent resection of both a primary lung cancer and the associated brain metastasis. One patient underwent resection of 2 separate primary lung cancers and the associated metastases. The 12 men and 7 women ranged in age from 42 to 67 years (mean, 54.6 years). The cell type was adenocarcinoma in 12 tumors, squamous or adenosquamous cell in 5, large cell undifferentiated or anaplastic in 2, and malignant carcinoid in 1 tumor. The types of resection were as follows: lobectomy for 12 neoplasms, pneumonectomy for 5, bilobectomy for 2, and wedge resection for 1 neoplasm. Radiotherapy to the brain was given in connection with sixteen of the twenty craniotomies. The patient with 2 separate primary neoplasms survived 19 years before dying 5 months after the second craniotomy. The mean survival is 8.0 +/- 2.1 years (+/- the standard error), and the median survival is 1.67 years. Survival at 1 year was 65 +/- 10.7% and at 5 years, 45 +/- 11.1%. On univariate analysis, the following factors were found to correlate significantly with longer survival: a lung tumor in Stage I or II; negative mediastinal nodes; curative rather than palliative resection of the lung tumor; and age younger than 55 years. However, on multivariate analysis, only curative resection was a significant factor (p less than 0.01). We believe these results justify continued application of this combined surgical approach to patients having limited-stage lung cancer with a solitary brain metastasis.

Use of a zipper in cardiac surgical operations

A simplified technique to gain repeated access to the median sternotomy incision is presented. The technique involves the use of a sterile polyester zipper attached to the skin edge. The sternum remains open. Unzipping the zipper allows for repeated relief of cardiac tamponade and viewing of cardiac action. Other advantages include prevention of cardiac compression or kinking of assist device cannulas from sternal closure, ease in changing of dressings, and quick removal of ventricular assist devices without reopening the sternum.

Two-step purification of tryptophan-accepting tRNA from Bacillus stearothermophilus

Tryptophan-accepting tRNA has been purified essentially to homogeneity from Bacillus stearothermophilus. Crude tRNA was chromatographed first on benzoylated DEAE-cellulose and then on Sepharose 4B with reverse salt gradient elution. The product has tryptophan acceptor activity in excess of 2 nmol [14C]tryptophan per A260 unit. This procedure avoids costly aminoacylation, a step characteristic of other one- and two-step procedures. In two separate purifications 7 and 11 mg of tRNAtrp were prepared from 750 and 1000 g of frozen cells, respectively. This yield compares favorably with that from other procedures. The pure tRNAtrp has been crystallized under several different conditions.

Management of penetrating cardiac injuries: the role of emergency room thoracotomy

Sixty-four consecutive patients with penetrating cardiac injuries were treated between January, 1977, and January, 1983, at the University of Maryland Hospital. Twenty-eight patients had major associated injuries of other organs. The patients were divided into groups according to their clinical status on arrival. An aggressive approach was utilized including early emergency room (ER) thoracotomy for "lifeless" or deteriorating patients. Three patients required immediate cardiopulmonary bypass for repair of their injuries. Twenty-one (57%) of the 37 patients undergoing ER thoracotomy survived; most of the deaths occurred in patients arriving "lifeless" from gunshot wounds. Twenty-four (89%) of the 27 patients who were in stable enough condition to undergo initial repair in the operating room (OR) survived. Overall survival was 45 patients (70%). Though superficial wound infections developed in 18 patients, there were no deep or systemic infections. None of the survivors sustained severe neurological sequelae. Five patients underwent late reoperations for closure of a ventricular septal defect (2), mitral valve replacement (1), and pericardiectomy (2) with no deaths. Though repair of penetrating cardiac injuries should preferably be carried out in the OR, immediate thoracotomy for "lifeless" or deteriorating patients can be performed in the ER with a low incidence of direct surgical complications and with high patient survival.

Chloramphenicol kills Haemophilus influenzae more rapidly than does ampicillin or cefamandole

The bactericidal effects of chloramphenicol and three beta-lactams (ampicillin, cefamandole, and penicillin G) were measured for 27 strains of Haemophilus influenzae type b isolated from the blood or cerebrospinal fluid of infected infants. Of the ampicillin-susceptible strains, 75% were killed by less than 2.0 micrograms of each antibiotic per ml; however, the concentration of the beta-lactam agents required for bactericidal activity was higher than that required for inhibitory activity. Chloramphenicol was the only agent which had no marked discrepancy between inhibitory and bactericidal concentrations regardless of beta-lactamase production. Importantly, chloramphenicol was more rapidly bactericidal than either ampicillin or cefamandole. The bactericidal requirement of ampicillin was increased by the presence of chloramphenicol for about one-third of the isolates examined. Neither the inhibitory nor the bactericidal activity of chloramphenicol was influenced by ampicillin. Synergy occurred for only two beta-lactamase-positive isolates. The more rapid bactericidal action of chloramphenicol persisted even in the presence of ampicillin. The rapid bactericidal action of chloramphenicol with or without ampicillin supports the use of chloramphenicol alone or with ampicillin for H. influenzae infections.

Repair of DNA alkylation induced in L1210 leukemia and murine bone marrow by three chloroethylnitrosoureas

The removal of DNA adducts is an essential step of DNA repair following exposure to chloroethylnitrosoureas. Adduct removal was evaluated in both L1210 and murine bone marrow DNA for lesions induced by three chloroethylnitrosoureas. 1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea, a marrow-toxic agent with high carbamoylating activity, was not removed in either system for at least 6 to 12 hr. These results were compared with those obtained with two glucose-linked chloroethylnitrosoureas, chlorozotocin and 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea. Both of these agents have low marrow toxicity at therapeutic doses. Chlorozotocin, which has very low chemical carbamoylating activity, was found to permit approximately 40% removal of drug-derived DNA adducts in both systems within the first 6 hr and approximately 50% by 18 hr. The second glucose-linked analog, 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea, has relatively high carbamoylating activity and was found to inhibit early removal of DNA adducts as effectively as does 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. It would thus appear that the selective marrow-sparing property of the sugar-linked chloroethylnitrosoureas is not dependent upon carbamoylation-mediated differences in the rate and extent of DNA adduct removal. In view of the comparable therapeutic activity of the three drugs for L1210 leukemia, therapeutic efficacy does not appear to be impaired by the increased rate of adduct removal observed with chlorozotocin in this system.

Dipyridamole-aspirin as thromboembolic prophylaxis in patients with aortic valve prosthesis. Prospective study with the Model 2320 Starr-Edwards prosthesis

In a prospective study, the efficacy of a dipyridamole-aspirin regimen in prevention of thromboembolism was evaluated in 50 patients having isolated aortic valve replacement with the Model 2320 Starr-Edwards prosthesis. These operations were performed between February, 1972, and October, 1974. In 1,380 patient-months of follow-up, there was a 20% incidence of thromboembolism with a rate of 8.7/100 patient-years and a 19% probability of an embolic episode occurring by 3 years. Seven patients had transient episodes, two had permanent neurologic residua, and one patient died. Comparison is made to a similar group of patients having solitary aortic valve replacement but receiving no medication, studied by Starr and associates. There was no statistical difference in the incidence of thromboembolism between the two groups. In November, 1975, all patients were converted to a regimen of warfarin therapy. Since conversion to anticoagulation, there have been two thromboembolic episodes in 2,132 patient-months of follow-up for a rate of 1.1/100 patient-years. We conclude that the use of antiplatelet therapy in the form of dipyridamole-aspirin is inadequate for routine thromboembolic prophylaxis following SE 2320 aortic valve replacement.

Delayed pericardial disease after radiotherapy

Delayed chronic constrictive pericarditis developed in seven patients 51 to 268 (mean 116) months after radiotherapy. Six of the seven complained of exertional dyspnea that was initially believed to be caused by mediastinal fibrosis. All patients had raised jugular venous pressure, although in two patients this finding was not appreciated by the primary physician. There were no consistent noninvasively identifiable features to allow prediction of constrictive pericarditis other than consideration of its existence and careful examination of the cardiovascular system. All patients had constrictive pericarditis proved at cardiac catheterization. Of the five patients who underwent pericardiectomy, two had an excellent functional result, one has residual pericardial constriction and two died of unrelated causes. Recommendations for the treatment of radiation-induced pericardial disease are given.

Giant coronary pseudoaneurysm. Five-year follow-up after bypass grafting

A roentgenogram of the shoulder in a 25-year-old man with an athletic injury revealed a large mass along the left heart border. Evaluation with coronary arteriography established the diagnosis of a massive aneurysm of the left anterior descending coronary artery. The aneurysm was excised and a saphenous vein bypass graft was placed into the distal artery. Histologic examination revealed that the excised segment was a false aneurysm. Five years postoperatively, the patient is asymptomatic and the graft remains widely patent.

Value of anterior mediastinotomy in bronchogenic carcinoma of the left upper lobe

Neoplasms of the left upper lobe may spread directly to the anterior mediastinal group of nodes without involving the inferior tracheobronchial, superior tracheobronchial, or paratracheal nodal chain. Routine cervical mediastinoscopy does not sample the anterior mediastinal node group. Parasternal anterior mediastinotomy was performed in 28 patients with left upper lobe carcinoma and normal findings from cervical mediastinoscopy. Despite the normal findings at cervical mediastinoscopy, 10 of the 28 patients were deemed to have inoperable disease because of spread of the neoplasm to the anterior nodal group or because of direct neoplastic involvement of the aorta or main pulmonary artery. All patients in whom results of anterior mediastinotomy were normal had resectable lesions at thoracotomy. Fourteen of the 16 patients who came to thoracotomy had normal hilar nodes. Parasternal anterior mediastinotomy, introduced by Chamberlain, should be performed in addition to standard cervical mediastinoscopy if the nodal drainage of left upper lobe neoplasms is to be more completely evaluated. Combining these two procedures samples all major drainage pathways except the posterior mediastinal nodal chain.

Thoracic traction for median sternotomy dehiscence

Standard management of median sternotomy dehiscence sometimes fails to achieve lasting reduction and fixation of the sternal halves. An effective method of external thoracic traction that augments internal fixation of the sternal fracture is presented.