Stem cell-based strategies and challenges for production of cultivated meat

Cultivated meat scale-up and industrial production will require multiple stable cell lines from different species to recreate the organoleptic and nutritional properties of meat from livestock. In this Review, we explore the potential of stem cells to create the major cellular components of cultivated meat. By using developments in the fields of tissue engineering and biomedicine, we explore the advantages and disadvantages of strategies involving primary adult and pluripotent stem cells for generating cell sources that can be grown at scale. These myogenic, adipogenic or extracellular matrix-producing adult stem cells as well as embryonic or inducible pluripotent stem cells are discussed for their proliferative and differentiation capacity, necessary for cultivated meat. We examine the challenges for industrial scale-up, including differentiation and culture protocols, as well as genetic modification options for stem cell immortalization and controlled differentiation. Finally, we discuss stem cell-related safety and regulatory challenges for bringing cultivated meat to the marketplace.

Jaundice and a testicular lump: a rare cause of malignant biliary obstruction

Biliary obstruction from metastatic deposits in the pancreas is rare. We present a case of primary testicular lymphoma (PTL) with pancreatic metastasis. A 56-year-old man presented to the general surgical department with signs and symptoms of obstructive jaundice. A computed tomography scan revealed multiple pancreatic metastases and a right primary testicular malignancy. Histology and positron emission tomography scanning subsequently confirmed PTL with pancreatic metastases. Metastasis to the pancreas from primary testicular malignancy is extremely rare. There is variation in prognosis between primary and secondary pancreatic malignancies and therefore in atypical cases of malignant biliary obstruction consideration must be given to the rarer secondary malignancies.

Jaundice and a testicular lump: a rare cause of malignant biliary obstruction

Biliary obstruction from metastatic deposits in the pancreas is rare. We present a case of primary testicular lymphoma (PTL) with pancreatic metastasis. A 56-year-old man presented to the general surgical department with signs and symptoms of obstructive jaundice. A computed tomography scan revealed multiple pancreatic metastases and a right primary testicular malignancy. Histology and positron emission tomography scanning subsequently confirmed PTL with pancreatic metastases. Metastasis to the pancreas from primary testicular malignancy is extremely rare. There is variation in prognosis between primary and secondary pancreatic malignancies and therefore in atypical cases of malignant biliary obstruction consideration must be given to the rarer secondary malignancies.

"I wanted to close the chapter completely … and I feel like that [carrying naloxone] would keep it open a little bit": Refusal to carry naloxone among newly-abstinent opioid users and 12-step identity

BACKGROUND

12-step programs aim to address drug-related harms, like opioid overdose, via abstinence. However, abstaining from opioids can diminish tolerance, which increases risk for overdose death upon resumption. A recent study found that desire to abstain from drugs inhibited willingness to participate in take-home naloxone programming, which was linked to perceptions of harm reduction strategies being tied to drug use. In the present study, we uncovered a similar phenomenon occurring among newly-abstinent participants who were refusing to carry naloxone.

METHODS

This study is an analysis of broader qualitative data collected throughout Southern California among persons who use opioids, including those recently abstinent. Preliminary analysis revealed that those newly abstinent refused to accept naloxone at the end of interviews, and so we began probing about this (N=44). We used thematic analysis and author positionality to explicate the emergent phenomenon and applied social identity theory to conceptualize findings.

RESULTS

Mechanisms underlying naloxone refusal included its tie to a drug-using identity that newly-abstinent participants were attempting to retire. Carrying naloxone was also viewed as pointless due to doubt of witnessing an overdose again. Furthermore, the thought of being equipped with naloxone was not believed to be congruent with an abstinent identity, e.g. "me carrying it [naloxone] is making me feel like I'm going to be hanging out with people that are doing it [using drugs]."

CONCLUSION

Recent detoxification heightens vulnerability to overdose, which other newly-abstinent peers might be positioned to respond to as bonds are formed through 12-step identity formation. However, naloxone is often refused by this group due to perceived 12-step identity clash. While some treatment spaces distribute naloxone, 12-step identity associated behavioral expectations appear to conflict with this strategy. Reframing these disconnects is essential for expanding the lifesaving naloxone community safety net.

The intersection of gender and drug use-related stigma: A mixed methods systematic review and synthesis of the literature

BACKGROUND

Substance use-related stigma is a significant barrier to care among persons who use drugs (PWUD). Less is known regarding how intersectional identities, like gender, shape experiences of substance use-related stigma. We sought to answer the following question: Do men or women PWUD experience more drug use stigma?

METHODS

Data were drawn from a systematic review of the global, peer-reviewed scientific literature on substance use-related stigma conducted through 2017 and guided by the Stigma and Substance Use Process Model and PRISMA guidelines. Articles were included in the present analysis if they either qualitatively illustrated themes related to the gendered nature of drug use-related stigma, or quantitatively tested the moderating effect of gender on drug use-related stigma.

RESULTS

Of the 75 studies included, 40 (53 %) were quantitative and 35 (47 %) were qualitative. Of the quantitative articles, 22 (55 %) found no association between gender and drug use-related stigma, 4 (10 %) identified women who use drugs (WWUD) were more stigmatized, and 2 (5 %) determined men who use drugs (MWUD) were more stigmatized. In contrast, nearly all (34; 97 %) of the qualitative articles demonstrated WWUD experienced greater levels of drug use-related stigma.

CONCLUSION

The quantitative literature is equivocal regarding the influence of gender on drug use-related stigma, but the qualitative literature more clearly demonstrates WWUD experience greater levels of stigma. The use of validated drug use-related stigma measures and the tailoring of stigma scales to WWUD are needed to understand the role of stigma in heightening the disproportionate harms experienced by WWUD.

"Generally, you get 86'ed because you're a liability": An application of Integrated Threat Theory to frequently witnessed overdoses and social distancing responses

While rates of opioid overdose deaths in North American have increased exponentially in recent years, most overdoses are not fatal, especially when witnesses are present and can intervene. Previous research has found that some people who use drugs [PWUDs] trained in overdose response might cut social ties with frequent overdosers, leading to more solitary opioid use and risk of death if someone overdoses alone. To examine the phenomenon of social distancing of people who overdose frequently, we used data from fifty-two in-depth qualitative interviews collected in Southern California with PWUDs who had recently witnessed an opioid overdose. Transcripts were reviewed and coded thematically, using the Integrated Threat Theory (ITT) to conceptualize the observed phenomenon. ITT outlines how realistic and symbolic threats are experienced by a group. We found that while some participants acknowledged the role of adulterated street drugs in overdoses, individualized blame was nonetheless imposed. Accusations of careless drug use practices fostered negative stereotyping towards frequent overdosers. This was attributed to the need to summon 911 for rescue, which often resulted in police dispatch. The intergroup relationship between police and PWUDs is precarious as police pose realistic threats onto PWUDs - such as incarceration, eviction, and manslaughter charges - leading to intragroup anxiety among PWUDs about future overdose events, and labelled frequent overdosers as liabilities. These threats, and inter/intra-group conflict, explained one reason how and why non-fatal overdoses led to social distancing events. People who overdose frequently were also accused of breaking the norm of drug user surreptitiousness; a symbolic threat that endangered the group due to police exposure. Social distancing might dampen exposure to the protective effect of peer-led interventions such as take-home naloxone programs, increasing risk of overdose death. This phenomenon highlights how intergroup dynamics are driving intragroup processes. Suggestions for tailoring public health interventions are discussed.

Assessing the short-term outcomes of a community-based intervention for overweight and obese children: The MEND 5-7 programme

OBJECTIVE

The aim of this study was to report outcomes of the UK service level delivery of MEND (Mind,Exercise,Nutrition...Do it!) 5-7, a multicomponent, community-based, healthy lifestyle intervention designed for overweight and obese children aged 5-7 years and their families.

DESIGN

Repeated measures.

SETTING

Community venues at 37 locations across the UK.

PARTICIPANTS

440 overweight or obese children (42% boys; mean age 6.1 years; body mass index (BMI) z-score 2.86) and their parents/carers participated in the intervention.

INTERVENTION

MEND 5-7 is a 10-week, family-based, child weight-management intervention consisting of weekly group sessions. It includes positive parenting, active play, nutrition education and behaviour change strategies. The intervention is designed to be scalable and delivered by a range of health and social care professionals.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was BMI z-score. Secondary outcome measures included BMI, waist circumference, waist circumference z-score, children's psychological symptoms, parenting self-efficacy, physical activity and sedentary behaviours and the proportion of parents and children eating five or more portions of fruit and vegetables.

RESULTS

274 (62%) children were measured preintervention and post-intervention (baseline; 10-weeks). Post-intervention, mean BMI and waist circumference decreased by 0.5 kg/m(2) and 0.9 cm, while z-scores decreased by 0.20 and 0.20, respectively (p<0.0001). Improvements were found in children's psychological symptoms (-1.6 units, p<0.0001), parent self-efficacy (p<0.0001), physical activity (+2.9 h/week, p<0.01), sedentary activities (-4.1 h/week, p<0.0001) and the proportion of parents and children eating five or more portions of fruit and vegetables per day (both p<0.0001). Attendance at the 10 sessions was 73% with a 70% retention rate.

CONCLUSIONS

Participation in the MEND 5-7 programme was associated with beneficial changes in physical, behavioural and psychological outcomes for children with complete sets of measurement data, when implemented in UK community settings under service level conditions. Further investigation is warranted to establish if these findings are replicable under controlled conditions.

HER-2/neu expression in germ cell tumours

AIMS

To determine the rate of HER-2/neu positivity of germ cell tumours by immunohistochemistry (IHC) and by fluorescence in situ hybridisation (FISH).

PATIENTS/METHODS

Ninety six archival, paraffin wax embedded pathology specimens were chosen from four groups of germ cell tumours. IHC for HER-2/neu was performed with the HercepTest kit; FISH analysis was performed with the INFORM assay and confirmed with a centromere 17 probe.

RESULTS

Twenty two of 96 specimens overexpressed the HER-2/neu protein when measured by IHC. Only three specimens showed HER-2/neu gene amplification by FISH. There was no correlation between the results obtained by IHC and FISH.

CONCLUSIONS

The lack of concordance between IHC and FISH makes it unlikely that overexpression of the HER-2/neu protein in germ cell tumours is of prognostic or therapeutic relevance. Because of the low rate of HER-2/neu gene amplification in germ cell tumours, a clinical trial of trastuzumab treatment in patients with germ cell tumours is not warranted.

Eradication of established tumors by vaccination with Venezuelan equine encephalitis virus replicon particles delivering human papillomavirus 16 E7 RNA

The etiological role of human papillomaviruses (HPV) in cervical and other cancers suggests that therapeutic vaccines directed against requisite viral antigens may eradicate tumors or their precursors. A Venezuelan equine encephalitis (VEE) alphavirus vector delivering the HPV16 E7 RNA was evaluated for antitumor efficacy using a murine E7+ tumor model. Vaccination with VEE replicon particles expressing E7 (E7-VRP) induced class I-restricted CD8+ T-cell responses as determined by IFN-gamma enzyme-linked immunospot (ELISPOT), tetramer, and cytotoxicity assays. E7-VRP vaccination prevented tumor development in all of the mice and effectively eliminated 7-day established tumors in 67% of tumor-bearing mice. The induction of protective T-cell responses was dependent on CD8+, but not CD4+ T cells. Long-lasting T-cell memory responses developed in E7-VRP-vaccinated mice as determined by complete protection from tumor challenge 3 months after the final vaccination. These promising results highlight the potent CD8+ T-cell-mediated antitumor effects elicited by VEE replicon-based vectors and support their further development toward clinical testing against cervical intraepithelial neoplasia or carcinoma.

Music training and mathematics achievement

Iowa Tests of Basic Skills (ITBS) mathematics scores of eighth graders who had received music instruction were compared according to whether the students were given private lessons. Comparisons also were made between students whose lessons were on the keyboard versus other music lessons. Analyses indicated that students who had private lessons for two or more years performed significantly better on the composite mathematics portion of the ITBS than did students who did not have private lessons. In addition, students who received lessons on the keyboard had significantly higher ITBS mathematics scores than did students whose lessons did not involve the keyboard. These results are discussed in relation to previous research on music training and mathematics achievement.

Systematic implications of chromosomal data from two insular species of Peromyscus from the Gulf of California

G- and C-banded karyotypes for two insular species of deer mice, Peromyscus slevini and P. sejugis, are described and analyzed relative to the evolutionary relationship of these species to and their inclusion within the P. maniculatus species group. The chromosomal phenotype of P. slevini is unique among all banded karyotypes reported for Peromyscus, and comparison with published karyotypes suggests that P. slevini has systematic affinities with either the P. boylii or P. mexicanus species groups. The karyotypic data for P. sejugis clearly align these mice with P. maniculatus and provide a diagnostic character that supports the specific distinction between these taxa.

Potential for plasmid DNAs as vaccines for the new millennium

The advent of new technology and the unmet needs of old and new epidemics of infectious diseases have stimulated a new era of vaccinology. One of the most novel approaches employs plasmid DNA engineered to express one or more genes of the pathogen in mammalian cells. Plasmids may also express cytokine or costimulatory molecules to 'direct' the immune response and/or express altered forms of the antigen to direct it to a specific intracellular compartment or a specific extracellular receptor. The quality of immune responses generated by DNA vaccines in animals has previously only been equaled by live attenuated viral vaccines. The immune stimulating activity of DNA vaccines, combined with their versatility, suggests vast potential for these vaccines.

A prospective, multidisciplinary evaluation of premenopausal women with iron-deficiency anemia

OBJECTIVE

The cause of iron deficiency anemia (IDA) in premenopausal women is often presumed to be menstrual blood loss. The purpose of this study was to determine the diagnostic value of a comprehensive gynecological and gastrointestinal evaluation in premenopausal women with IDA.

METHODS

Nineteen premenopausal, nonpregnant women older than 18 yr of age with IDA defined by a hemoglobin < 12 gm/dl with serum ferritin < 10 ng/ml participated in the study. Evaluations included directed history and physical examination by a specialist in gynecology and a subspecialist in gastroenterology, esophagogastroduodenoscopy, colonoscopy, upper gastrointestinal radiography with small bowel follow-through, antiendomysial antibody, and fecal occult blood tests.

RESULTS

Seven of 19 (37%) premenopausal women with IDA were diagnosed to have a gynecological cause of anemia by a specialist in that field. Although only four of these seven patients had digestive complaints, all but one (86%) were discovered to have gastrointestinal disease by upper endoscopy; findings were duodenal ulcer and Helicobacter pylori (H. pylori) gastritis (one), esophagitis and H. pylori gastritis (one), erosive esophagitis (one), gastric arteriovenous malformations (one), and nodular/erosive H. pylori gastritis (two). Fecal occult blood testing was positive in only two (29%) subjects; upper endoscopy revealed erosive esophagitis and gastric arteriovenous malformations. Twelve of the 19 (63%) premenopausal women with IDA were not diagnosed to have a gynecological source of anemia by a specialist in that field. Fecal occult blood testing was negative among all women tested and the only digestive complaint was heartburn (pyrosis) in seven. Each was identified to have esophagitis, duodenal ulcer, or gastritis by upper endoscopy. Colonoscopic examination of the 12 subjects without gynecologic etiology for IDA revealed pan colitis (one), diverticulosis (one), diverticulosis and melanosis coli (one), hyperplastic polyps (one), and nodular lymphoid aggregates (one).

CONCLUSIONS

Significant upper gastrointestinal disease is identifiable among most premenopausal women with IDA (18 of 19 or 95%), even when careful evaluation by a specialist in gynecology suggests a gynecological source. Upper endoscopy should be considered in the evaluation of all premenopausal women with IDA expressing digestive complaints or in those with IDA refractory to iron supplementation. Lower endoscopic examination may be reserved for those women with symptoms or signs suggestive of colorectal disorders.

Risk stratification for adverse economic outcomes in cardiac surgery

BACKGROUND

Recent emphasis on cost-containment in the health-care environment has focused attention on the cost of medical procedures. Selection of the appropriate treatment for coronary artery disease is of increasing concern. Coronary artery bypass grafting is common and very expensive, and this procedure will continue to be examined closely by reimbursement systems, particularly with regard to the lower initial cost of coronary angioplasty as a competing therapy.

METHODS

Duke University Medical Center has a sophisticated accounting system that enables individual cost components to be identified, facilitates prospective analysis of cost/benefit, and aids allocation of limited hospital resources. In 1996, 1,114 coronary artery bypass procedures were performed at Duke. Preoperative patient characteristics were also analyzed in an attempt to predict risk factors for increased cost.

RESULTS

The median cost for these procedures was $20,682, excluding professional fees. Sixty percent of the costs were directly associated with patient care, and the other 40% were accounted for by indirect costs to support patient care. The most significant preoperative predictor of increased postoperative cost was the mortality estimate. If this variable was excluded from the analysis, other variables (for example, ejection fraction, age, identity of the surgeon, and congestive heart failure) were all related to increased costs.

CONCLUSIONS

Predicting costs based on preoperative variables offers the potential to reduce total costs through case-management strategies and aids in negotiating a risk-shared contract. However, cost reduction in routine care will have more financial impact than cost reduction by patient selection.

The effect of ordinances requiring smoke-free restaurants and bars on revenues: a follow-up

OBJECTIVES

The purpose of this study was to extend an earlier evaluation of the economic effects of ordinances requiring smoke-free restaurants and bars.

METHODS

Sales tax data for 15 cities with smoke-free restaurant ordinances, 5 cities and 2 counties with smoke-free bar ordinances, and matched comparison locations were analyzed by multiple regression, including time and a dummy variable for the ordinance.

RESULTS

Ordinances had no significant effect on the fraction of total retail sales that went to eating and drinking places or on the ratio between sales in communities with ordinances and sales in comparison communities. Ordinances requiring smoke-free bars had no significant effect on the fraction of revenues going to eating and drinking places that serve all types of liquor.

CONCLUSIONS

Smoke-free ordinances do not adversely affect either restaurant or bar sales.

Language arts achievement level, attitude survey format, and adolescents' attitudes towards reading

The joint effects of student achievement level and attitude survey format upon attitudes toward reading were investigated. Sixth-grade students completed reading attitude surveys involving a standard Likert-type format or one involving pictures of the comic strip character, Garfield. The survey items were identical for both formats; only the presentation format was varied. There was no significant main effect on attitude responses due to achievement level, but the main effect due to survey format was significant, with the Likert-type format producing significantly higher attitude responses than the Garfield format. The interaction between achievement level and format also was significant, with above average students and average students giving higher attitude responses than did below average students when the Garfield format was used. When the Likert-type format was used, average students and below average students gave higher attitude responses than did above average students. The results imply that attitude responses of adolescents can be manipulated by varying the format of the survey.

Persistence of T-cell clones in psoriatic lesions

BACKGROUND

We previously demonstrated a clonal dominance in the V beta 13.1 messages isolated from the lesional CD8+ T cells of psoriasis vulgaris, which suggested an interaction of V beta 13.1+ CD8+ T cells with skin antigens.

OBJECTIVES

To determine whether the clonality observed accurately reflected a clonal population of infiltrating T cells or was skewed by an overabundance of messages from a small number of cells, and to extend our study of V beta gene usage by lesional CD8+ T cells to 9 new patients.

DESIGN

Case study.

SETTING

Patients were enrolled at the Psoriasis Research Institute in Palo Alto, Calif, and samples were analyzed at The Immune Response Corporation in Carlsbad, Calif.

MAIN OUTCOME MEASURES

For the 2 previous patients, skin samples were sorted directly for V beta 13.1+ T cells, for which the T-cell receptors were sequenced. For the 9 new patients, CD8+ T cells were sorted and their T-cell receptor V beta gene usage measured using semiquantitative polymerase chain reaction with V beta-specific primers.

RESULTS

The directly sorted V beta 13.1+ T cells exhibited clonal dominance in both patients. The dominant V beta 13.1 clone in each patient was the same as that found in the previous 2 biopsy specimens for which CD8+ T cells were sorted. Additionally, in 8 of the 9 new patients examined, we again found a preferential usage of V beta 3 and/or V beta 13.1 genes by the lesional CD8+ T cells.

CONCLUSIONS

The clonality, which was found in the V beta messages of the sorted CD8+ T cells, accurately reflects the dominance of these clones in the infiltrating T cells. Moreover, the persistence in the same patient of the same clone for as long as 15 months and the overrepresentation of V beta 3 and/or V beta 13.1 in lesional CD8+ T cells in the new patients examined support the pathogenic role of T cells bearing these V betas.

Multicenter preoperative stroke risk index for patients undergoing coronary artery bypass graft surgery. Multicenter Study of Perioperative Ischemia (McSPI) Research Group

BACKGROUND

The paradox of present cardiac surgery is that the more elderly and debilitated patients benefit most from cardiac surgery compared with medical therapy, yet they sustain greater overall risk for morbidity and mortality after cardiac surgery. The goal of the present study was to develop a preoperative index predicting major perioperative neurological events in patients undergoing coronary artery bypass graft surgery.

METHODS AND RESULTS

As part of a prospective, multicenter, observational study (McSPI Research Group), we enrolled 2417 patients at 24 academic medical centers in the United States. Patients who died intraoperatively or had concomitant open-heart procedures were excluded from analysis, resulting in a total of 2107 for analysis. Sixty-eight patients (3.2%) developed adverse neurological events, defined as cerebrovascular accident, transient ischemic attack (TIA), or persistent coma. Bivariate analysis was applied to determine associations between preoperative variables and neurological events. Significant bivariate predictors were identified then logically grouped, and for each cluster, a score was calculated based on principal components. Key predictor variables were age, history of previous neurological disease, diabetes, history of vascular disease, previous coronary artery surgery, unstable angina, and history of pulmonary disease, the coefficients for which were used to develop a preoperative stroke risk index that was validated by bootstrap (c-index = 0.778). Stroke risk could then be determined for each patient, calculating a patient's risk for stroke within 95% confidence intervals.

CONCLUSIONS

With the McSPI stroke risk index developed in this study, neurological risk can be estimated, and the most appropriate group for perioperative therapy can be identified. Further refinement and validation of this index, however, are necessary and are under way in current studies.

Homology of partial primary sequences between alpha-enolase and a suppressive lymphokine from human T cells

A relationship is described between TS--a human suppressive lymphokine produced by hybridoma T cells--and alpha-enolase from the U937 monocyte human cell line. A strong homology (92%) was observed by comparing the internal amino acid sequences of 6 TS peptides, corresponding to 52 residues, with the complete sequence of alpha-enolase. The molecular masses of these two molecules were found to be of about 47 kDa and both were detected with the same monoclonal antibody to TS. In contrast, no immunosuppressive activity was detected with the purified enolase fraction, whereas TS did not show any enolase activity. A suppressive monokine secreted by U937 cells was found to be unrelated with TS. Theses results suggest that the TS immunosuppressive factor despite its absence of enzyme activity, belongs to the enolase family.

A comparison of topical agents to relieve nipple pain and enhance breastfeeding

BACKGROUND

Nipple soreness is one reason why breastfeeding women wean their infants. This study examined the effectiveness of three topical agents--USP-modified lanolin, warm water compresses, and expressed breast milk with air drying--in alleviating nipple pain, and if early predictors of breastfeeding at six weeks could be determined.

METHODS

One hundred seventy-seven breastfeeding, primiparous women were randomly assigned to one of four groups. All women received education about breastfeeding technique. Numeric rating scales were used to discriminate levels of pain intensity, pain affect, and strength of sucking on day 1. Participants were interviewed by telephone on postpartum days 4, 7, and 14, and during week 6 using the same scales.

RESULTS

No significant differences were found among groups for pain intensity, pain affect, or duration of breastfeeding. Results of a logistic regression indicated that older mothers and those who were exclusively breastfeeding (no supplemental feeding) were most likely to be breastfeeding six weeks postpartum. Raw scores supported the use of warm compresses.

CONCLUSION

Further investigation is required into ways of supporting young mothers and how caregivers provide support to breastfeeding mothers in the early weeks after childbirth.

Defining neuropsychological dysfunction after coronary artery bypass grafting

BACKGROUND

Despite the large body of literature documenting the presence of cognitive decline after coronary artery bypass grafting, there is little consensus as to the frequency and extent of cognitive impairment. One potential reason for this lack of agreement is the absence of uniform criteria for assessing cognitive decline.

METHODS

Two hundred thirty-two patients underwent cognitive testing the day before operation and were examined before discharge, and at 6 weeks and 6 months after grafting. For comparative purposes, five different sets of criteria were used to define cognitive decline.

RESULTS

There was little agreement between the criteria as to which patients declined at each test period. The incidence of decline ranged from 66% to 15.3% before discharge, 34% to 1.1% at 6 weeks, and 19.4% to 3.4% at 6 months.

CONCLUSIONS

A large variation in reported incidence of cognitive decline after coronary artery bypass grafting can be attributed to the different criteria used to define cognitive impairment.

Ascent rate, post-dive exercise, and decompression sickness in the rat

The effects of ascent rate and post-dive exercise on the incidence of decompression sickness (DCS) were investigated in six groups of 20 rats exposed for 2 h at a pressure equivalent to 240 feet of sea water (fsw; 735 kPa). Ascent rates were 30, 45, and 60 fsw/min (92, 138, 184 kPa/min), and the rats either rested after the exposure or exercised by walking for 30 min on a treadmill at 1.6 m/min. Post-dive signs included respiratory distress, difficulty walking, paralysis, and death. DCS was scored as non-fatal at 30-min post-dive or fatal at any time. Analysis by ordinal logistic regression indicated more DCS with post-dive exercise (P = 0.0112) and at 45 (P = 0.0011) and 60 fsw/min (P = 0.0001) compared to 30 fsw/min. Survival analysis suggested earlier death at 60 fsw/min compared to 30 fsw/min (P = 0.0006). Similar effects have been reported for the less severe DCS that occurs in humans.

A comparison of amrinone with sodium nitroprusside for control of hemodynamics during infrarenal abdominal aortic surgery

OBJECTIVES

The control of hemodynamic changes during surgical resection of abdominal aortic aneurysms (AAA) remains a challenge to anesthesiologists. In the past, hypertensive episodes have been treated with sodium nitroprusside (SNP). However, amrinone may provide some benefits when compared with SNP because of its positive inotropic and vasodilatory properties. Therefore, the purpose of this study was to compare amrinone with SNP for hemodynamic control during AAA surgery.

DESIGN

This study was a prospective, randomized investigation.

SETTING

This study was performed at a single university hospital.

PARTICIPANTS

This study included 20 patients undergoing AAA resection.

INTERVENTIONS

After institutional review board approval, participants were randomized to receive either SNP (group N = 10) or amrinone (group A = 10). Both agents were started 10 minutes before aortic cross-clamping and discontinued 10 minutes before unclamping. Anesthesia was induced with thiopental or etomidate and maintained with oxygen, nitrous oxide, isoflurane, fentanyl, and vecuronium. Hemodynamic measurements included heart rate, systolic and diastolic blood pressure, cardiac output, systolic and diastolic pulmonary artery pressure, pulmonary capillary wedge pressure, central venous pressure, mixed venous oxygen saturation, electrocardiogram, and ST-T wave trend analysis.

MEASUREMENTS AND MAIN RESULTS

Demographic and clinical characteristics for the two groups were similar. Mixed venous oxygen saturation was significantly lower (p < 0.05) in group N immediately after unclamping. There were no differences between groups for the other measurements studied. There were no episodes of myocardial ischemia in either group.

CONCLUSIONS

This study demonstrates that amrinone provides equivalent hemodynamic control to SNP during abdominal aortic aneurysm surgery because it allows moderate reductions in blood pressure without affecting other hemodynamic measurements. Further studies are needed to assess whether patients with poor preoperative left ventricular function would benefit from amrinone management during AAA resection.

Clinical use of a frameless stereotactic arm: results of 325 cases

The viewing wand is a frameless stereotactic arm that can be used in conjunction with computerized tomography (CT) or magnetic resonance (MR) imaging to provide image-based intraoperative navigation. The authors report a series of 325 cases in which the viewing wand was used and evaluated for its utility, ease of integration into the standard surgical setup, reliability, and real-world accuracy. The use of the system was associated with minimal additional effort or time spent in setting up the procedure as long as a trained technician performed the data transfer and reconstruction. The viewing wand was used in 165 cases in conjunction with CT and 145 cases with MR imaging. The system was reliable, achieving a useful registration in 310 of 325 cases (95.4%). Fiducial-based registration was more accurate than an anatomical landmark-surface fit algorithm method of registration (mean 2.8 vs. 5.6 mm error, respectively, for CT; and mean 3.0 vs. 6.2 mm for MR imaging). The actual error of the system in estimating the position of the probe tip just after registration was judged by the operating surgeon to be less than 2 mm in 92% of MR imaging cases and in 82% of CT cases, between 2 and 5 mm in 7% of MR imaging and 17% of CT cases, and greater than 5 mm in less than 1% of MR imaging and 1.2% of CT cases. The accuracy of the system degraded during the operation, so that by the third evaluation the error was estimated to be less than 2 mm in 77% of MR imaging and 62% of CT cases. Overall, the viewing wand was found to be reliable and accurate. This real-world accuracy was sufficient for a broad range of applications including glioma resection, cerebrospinal fluid shunting procedures, resection of small subcortical masses, and temporal lobe resection. The system is a useful navigational aid that allows a direct approach to intracranial pathology without the drawbacks of application and the limitations of a stereotactic frame.

Differential age effects of mean arterial pressure and rewarming on cognitive dysfunction after cardiac surgery

Central nervous system dysfunction is a common consequence of otherwise uncomplicated cardiac surgery. Many mechanisms have been postulated for the cognitive dysfunction that is part of these neurologic sequelae. The purpose of our investigation was to evaluate the effects of mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) and the rate of rewarming on cognitive decline after cardiac surgery. Two hundred thirty-seven patients completed preoperative and predischarge neuropsychologic testing. MAP and temperature were recorded at 1-min intervals using an automated anesthesia record keeper. MAP area less than 50 mm Hg (time and degree of hypotension), as well as the maximal rewarming rate, were determined for each patient. Multivariable linear regression revealed that the rate of rewarming and MAP were unrelated to cognitive decline. However, interactions significantly associated with cognitive decline were found between age and MAP area less than 50 mm Hg on one measure, and between age and rewarming rate in another, identifying susceptibility of the elderly to these factors. Although MAP and rewarming were not the primary determinates of cognitive decline in this surgical population, hypotension and rapid rewarming contributed significantly to cognitive dysfunction in the elderly.

Are modern imaging techniques over diagnosing ureteropelvic junction obstruction?

Since the widespread use of real-time ultrasonography in the early 1980s, ureteropelvic junction obstruction has been diagnosed at earlier ages and prenatally on a presumptive basis. However, substantial controversy exists over the diagnosis and treatment of ureteropelvic junction obstruction. We conducted an epidemiological study to determine if modern imaging techniques are leading to the over diagnosis of ureteropelvic junction obstruction. Records were collected retrospectively from 3 hospitals serving 2 adjacent counties to determine the number of pyeloplasties performed in 1970 to 1992. The 2 university hospitals and 1 large private hospital provide a wide variety of services and choice of urologists, and so it was assumed that most patients requiring pyeloplasty in the area would be captured. Of the 555 pyeloplasties 240 (43%) were performed on children 12 years old or younger. Logistic regression analysis revealed an overall increase of pyeloplasties per year of 56.8% in 23 years, which was not markedly different from the population growth in the area in the same period (49.3%). A statistically significant increase in the number of pyeloplasties performed in the first year of life was noted. This trend appeared to begin in 1981: 8 pyeloplasties were performed in the first year of life between 1970 and 1980 compared to 91 between 1981 and 1992. Pyeloplasties in children 1 to 6 years old increased with time at a much lower rate that was not statistically significant and the number of pyeloplasties decreased in those 7 to 12 years old. Therefore, it appears that modern imaging techniques are not leading to an over diagnosis of ureteropelvic junction obstruction but to detection of the disease at an earlier age.

CD8+ T-cells in psoriatic lesions preferentially use T-cell receptors V beta 3 and/or V beta 13.1 genes

Restricted T-cell receptor V beta gene use in animal models of autoimmune disease has led to the development of strategies to treat autoimmune disease by targeting the T-cell receptors of the pathogenic T-cells. Restricted T-cell receptor gene use has been noted in human autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. We report here the finding of restricted T-cell receptor gene use in psoriasis vulgaris, as well. Our results show an elevated skin (over PBL) expression of V beta 3 and/or V beta 13.1 messages in the CD8+ T-cells in a majority of patients studied. CDR3 sequence analysis on these two V beta s from the skin demonstrated monoclonality or marked oligoclonality. A second biopsy performed 3.5 to 8 months later in four patients, at the same or different lesions, again revealed an elevated V beta 3 and/or V beta 13.1 expression and clonality. Moreover, in three of the four patients, the same TcR V beta CDR3 rearrangement was found in both biopsies, although there was no V beta CDR3 homology noted between patients. In two patients in which V beta 3 and/or V beta 13.1 was not elevated in the CD8+ T-cell population, an increase in V beta 17 gene use and clonality was found. The persistence of V beta 3- and/or V beta 13.1-bearing CD8+ T-cells in lesions that did not undergo resolution suggests their role as effector cells rather than as regulatory cells. The effector function of these CD8+ T-cells is further supported by the clonality of TcR V beta sequence data, which indicates they are recruited and expanded in situ. The V beta s identified in this study are candidate targets for selective immunotherapeutic intervention in psoriasis.

Jugular bulb saturation and mixed venous saturation during cardiopulmonary bypass

Systemic venous oxygen saturation is clinically used as an indicator of a satisfactory oxygen supply demand balance on cardiopulmonary bypass (CBP). Cerebral desaturation has been associated with postoperative cognitive dysfunction and has an incidence of 17% to 23% on bypass. We tested the hypothesis that systemic venous saturation did not correlate with jugular bulb venous saturation. Blood was drawn from the radial artery, jugular bulb catheter, and venous return line for determination of pH, oxygen tension and saturation, and carbon dioxide tension at four times during bypass: warm 1 (following initiation of CPB); cold 1 (stable hypothermia); cold 2 (hypothermia prior to rewarm); and warm 2 (nasopharyngeal temperature 36 degrees C to 37 degrees C). Correlations of jugular bulb and systemic venous saturation at cold 1 were r = 0.29, r2 = 0.08, and p = 0.0005, and at warm 2 were r = 0.22, r2 = 0.05, and p = 0.007. We conclude that systemic saturation is a poor indicator of cerebral saturation. The poor association of jugular and systemic pump venous saturations underscores our inability to evaluate adequacy of cerebral perfusion. Jugular saturation is lower than pump venous return blood, especially at times of lower oxygen delivery, thus either continuous invasive or noninvasive evaluation of cerebral oxygenation is required to evaluate the adequacy of cerebral perfusion.

Defining the relationship of oxygen delivery and consumption: use of biologic system models

To determine the most appropriate mathematical description of the relationship between oxygen consumption and oxygen delivery, we compared the statistical validity of a piecewise linear model to two different biologic system models--Michaelis-Menten (MM) kinetics (used for enzyme systems) and the exponential dose-response relationship (used to describe drug administration and induced response). Nine rabbits underwent five incremental steps of normovolemic hemodilution to progressively decrease DO2. VO2 was measured concurrently by a metabolic gas monitor. All three models (piecewise linear, Michaelis-Menten, and exponential) provided a very close population curve fit to the data points (r2 = 0.88, 0.91, and 0.92). However, there were significant differences in maximum predicted VO2 (VO2max)--6.8, 9.9, 7.2 ml O2.kg-1.min-1 (P < 0.0002)--and a wide range in the model-specific parameters for individual rabbits (critical DO2 6.5-11.8 ml O2.kg-1.min-1, Km 4.2-11.4 ml O2.kg-1.min-1, and kappa 0.12-0.23 ml O2-1.kg.min). In the curvilinear models, average and population parameters were not significantly different. However, in the piecewise linear model, population critical DO2 (10.9 ml O2.kg-1.min-1) was 30% more than the average critical DO2 (8.4 ml O2.kg-1.min-1) for the nine rabbits (P < 0.005). VO2max values predicted by the piecewise linear and exponential dose-response model were more consistent with those in previous publications than was the higher VO2max predicted by the MM model. The difference in the average versus population critical DO2 in the piecewise linear model meant that population modeling was inaccurate because it yielded a critical DO2 higher than that demonstrated by eight of nine individual rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

In-hospital and long-term outcome after porcine tricuspid valve replacement

Porcine bioprostheses are often used for tricuspid valve replacement, yet the long-term outcome after this procedure is not well documented. Therefore, the records of 129 patients undergoing tricuspid valve replacement with Carpentier-Edwards (n = 88) or Hancock (n = 41) prostheses between 1975 and 1993 were reviewed. The operation required a repeat median sternotomy in 66 of 129 (51%) patients, whereas 67 of 129 (52%) underwent double or triple valve replacement. Operative mortality was 14% (2/14) in patients undergoing first-time isolated tricuspid valve replacement and 27% (35/129) overall. Survival at 5, 10, and 14 years was 56% +/- 5%, 48% +/- 5%, and 31% +/- 9%, and freedom from tricuspid reoperation at 5, 10, and 14 years was 96% +/- 3%, 93% +/- 4%, and 49% +/- 17%. No valve thrombosis was observed. In this largest reported series of porcine bioprostheses in the tricuspid position, long-term freedom from valve-related events was excellent because of a low incidence of valve thrombosis and a valve durability of 13 to 15 years in a population with limited life expectancy.

Predictors of cognitive decline after cardiac operation

Despite major advances in cardiopulmonary bypass technology, surgical techniques, and anesthesia management, central nervous system complications remain a common problem after cardiopulmonary bypass. The etiology of neuropsychologic dysfunction after cardiopulmonary bypass remains unresolved and is probably multifactorial. Demographic predictors of cognitive decline include age and years of education; perioperative factors including number of cerebral emboli, temperature, mean arterial pressure, and jugular bulb oxygen saturation have varying predictive power. Recent data suggest a genetic predisposition for cognitive decline after cardiac surgery in patients possessing the apolipoprotein E epsilon-4 allele, known to be associated with late-onset and sporadic forms of Alzheimer's disease. Predicting patients at risk for cognitive decline allows the possibility of many important interventions. Predictive power and weapons to reduce cellular injury associated with neurologic insults lend hope of a future ability to markedly decrease the impact of cardiopulmonary bypass on short-term and long-term neurologic, cognitive, and quality-of-life outcomes.

Depression in male and female patients undergoing cardiac surgery

The present longitudinal study was designed to determine the prevalence of depression in male and female patients undergoing cardiac surgery, and to examine what factors are associated with depression before and after surgery. One day prior to surgery (T1), and one day prior to discharge from the hospital (T2), 141 patients completed a psychometric test battery including the Center for Epidemiological Studies Depression Scale (CES-D), the State-Trait Anxiety Inventory (STAI), and the Perceived Social Support Scale (PSSS). Data were also collected on 13 physiological measures. Forty-seven per cent of patients were depressed (defined as a score of 16 or above on the CES-D) at T1. Scores on the CES-D significantly increased from T1 (M = 15) to T2 (M = 20), with 61 per cent of patients classified as depressed at T2. Factors associated with depression at T1 were female gender, higher state anxiety, and less social support. Depressed patients at T2 were characterized by higher scores on the STAI at T2 and higher scores on the CES-D at T1. The prevalence of depression in cardiac surgery patients, particularly women, may be underrecognized and warrants increased attention.

Aging increases pharmacodynamic sensitivity to the hypnotic effects of midazolam

The effect of aging on the pharmacodynamics of midazolam was investigated in a double-blinded study involving 39 consenting patients ranging in age from 39 to 77 yr. Midazolam was infused intravenously (i.v.) using a pharmacokinetic model-driven drug infusion device to achieve a plasma midazolam concentration that was held constant for the 10-min duration of the study. Blood samples were obtained from the radial artery at 5 and 10 min for subsequent measurement of the plasma midazolam concentrations. With the 10-min sample, the patients were also assessed for the presence or absence of responsiveness to verbal command. To ensure that the pharmacodynamic end-point was assessed under the condition of a relative steady-state effect-site midazolam concentration, only those patients (n = 33) in whom the plasma midazolam concentration at 10 min was within 30% of the measured concentration at 5 min were included in the subsequent data analyses. Logistic regression was used to fit the verbal command response/no response data to a mathematical model that included patient age and the plasma midazolam concentration measured at 10 min. Cp50, the steady-state plasma midazolam concentration at which 50% of patients would be expected not to respond to a specific stimulus (e.g., verbal command), was calculated as a function of age from the parameterized logistic model. The midazolam Cp50 for response to verbal command decreased significantly (P = 0.034) with increasing patient age, demonstrating that aging increases pharmacodynamic sensitivity to the hypnotic effects of midazolam independent of pharmacokinetic factors.

The Mini Mental State Exam as a predictor of neuropsychological functioning after cardiac surgery

OBJECTIVE

The present longitudinal study was designed to: 1) determine the ability of the Mini Mental State Exam (MMSE) to predict neuropsychologic impairment based on neuropsychologic testing five to seven days and six weeks after cardiac surgery; and 2) to determine whether the traditional or the education-related MMSE norms are more appropriate to use for this purpose.

METHOD

The day before surgery (T1), before hospital discharge (T2), and six weeks after surgery (T3), 247 subjects completed a battery of five neuropsychologic tests. Subjects also completed the Center for Epidemiological Studies Depression Scale and the Speilberger State-Trait Anxiety Inventory. Subjects completed the MMSE two to three days after surgery.

RESULTS

Stepwise regression analyses revealed that the MMSE significantly predicted only a small portion of the variance in neuropsychologic test performance at T2, and to an even lesser extent at T3, over and above the demographic variables. In assessing the association between an impairment score (derived from the neuropsychologic test battery) and the MMSE, we found that the traditional MMSE cut-off score maximized specificity (number of true negatives) while the education-adjusted MMSE cut-off scores maximized sensitivity (number of true positives).

CONCLUSIONS

These results suggest that although the MMSE is widely used to assess cognitive mental status, it may have limited value in identifying patients with cognitive impairment post-cardiac surgery, and special attention must be paid to the cut-off scores used in interpreting the MMSE.

Jugular bulb saturation and cognitive dysfunction after cardiopulmonary bypass

Inadequate cerebral oxygenation during cardiopulmonary bypass may lead to postoperative cognitive dysfunction in patients undergoing cardiac operations. A psychological test battery was administered to 255 patients before cardiac operation and just before hospital discharge. Postoperative impairment was defined as a decline of more than one standard deviation in 20% of tests. Variables significantly (p < 0.05) associated with postoperative cognitive impairment are baseline psychometric scores, largest arterial-venous oxygen difference, and years of education. Jugular bulb hemoglobin saturation is significant if it replaces arterial-venous oxygen difference in the model. Factors correlated with jugular bulb saturation at normothermia were cerebral metabolic rate of oxygen consumption (r = -0.6; p < 0.0005), cerebral blood flow (r = 0.4; p < 0.0005), oxygen delivery (r = 0.4; p < 0.0005), and mean arterial pressure (r = 0.15; p < 0.05). Three measures were significantly related to desaturation at normothermia and at hypothermia as well: greater cerebral oxygen extraction, greater arterial-venous oxygen difference, and lower ratio of cerebral blood flow to arterial-venous oxygen difference. We conclude that cerebral venous desaturation occurs during cardiopulmonary bypass in 17% to 23% of people and is associated with impaired postoperative cognitive test performance.

Effect of aging on cerebral autoregulation during cardiopulmonary bypass. Association with postoperative cognitive dysfunction

BACKGROUND

Age is a predictor of cognitive dysfunction after cardiac surgery, but the mechanism is unknown. The purpose of our study was to determine whether age-related decrements in cognition are associated with cerebral blood flow (CBF) autoregulation during cardiopulmonary bypass (CPB).

METHODS AND RESULTS

Cognitive function testing was completed before surgery and before hospital discharge in 215 patients undergoing elective coronary artery bypass grafting (CABG) surgery. The battery consisted of seven tests with nine measures designed to evaluate memory, mood changes, and visuomotor speed and function. Pressure-flow and metabolic-flow cerebral autoregulation during hypothermic cardiopulmonary bypass were determined using the 133Xe clearance CBF method and radial artery and jugular bulb effluent to calculate cerebral metabolic rate (CMRO2) and cerebral AV difference (C[AV]O2). Pressure-flow autoregulation was tested by using two CBF measurements at stable hypothermia: one at stable mean arterial pressure (MAP) and the second 15 minutes later when MAP had increased or decreased > or = 20%. Metabolism-flow autoregulation was tested by varying the temperature (CMRO2) and measuring the coupling of CBF and CMRO2. Individual patient autoregulation was correlated with changes in cognitive measures. Cognitive performance declined in 6 of 9 measures after CABG surgery. Age predicted cognitive decline in 7 of 9 measures; short-term memory showed the greatest effect of age. Pressure-flow autoregulation during hypothermic CPB showed a small but significant (P < .0001) effect of pressure on CBF. There was no effect of age on the slope of CBF response to changes in MAP (pressure-flow autoregulation). There was a major effect of temperature on CBF during CPB (P < .0001). Coupling CBF and CMRO2 with changing temperature was unaffected by age. Changes in cognition were not associated with measures of cerebral autoregulation. However, increasing C(AV)O2 is associated with cognitive deficits in 5 of 9 measures; these associations were independent of age.

CONCLUSIONS

Increased age predisposes to impaired cognition after cardiac surgery. This decline in cognitive function in the elderly is not associated with age-related changes in cerebral blood flow autoregulation. The association of increased oxygen extraction with decline in some measures of cognitive function suggests that an imbalance in cerebral tissue oxygen supply, which is unrelated to age, contributes to acute cognitive dysfunction after cardiac surgery. Cognitive dysfunction after CPB in the elderly cannot be explained by impaired CBF autoregulation.

Preoperative determinants of postoperative costs associated with coronary artery bypass graft surgery

BACKGROUND

Procedure-related costs are of increasing concern in selecting the appropriate procedure for the treatment of coronary artery disease (CAD).

METHODS AND RESULTS

To determine what preoperative factors influence total postoperative hospital costs, data on 604 coronary artery bypass graft surgery (CABG) patients from 1990 to 1991 were analyzed. Professional fees were excluded. Hospital costs were computed by multiplying patient charges by the Medicare cost-to-charge ratio used in determining federal reimbursement. Median postoperative cost was $12,912 (range $7100 to $259,546). Data were analyzed with a semiparametric regression model. Patients dying in the hospital were censored at time of death. There were significant differences among surgeons in costs but no significant differences in operative mortality. Significant risk factors for increased cost after adjusting for surgeon were: older age (P < .0001), lower left ventricular ejection fraction (P < .0001), prior CABG (P < .0001), female sex (P < .0049), no prior percutaneous transluminal coronary angioplasty (P < .0091), increased degree of CAD (P < .0102), black race (P < .0190), and diabetes (P < .032).

CONCLUSIONS

These results suggest that preoperative characteristics have important economic and medical implications. Surgeons should compare their management strategies on the basis of data analysis to determine the most effective practice with regard to mortality and cost.