Close Cassini flybys of Saturn’s ring moons Pan, Daphnis, Atlas, Pandora, and Epimetheus

Saturn’s main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons’ morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons’ surfaces are determined by two competing processes: contamination by a red material formed in Saturn’s main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.

Fatty liver disease, glucose tolerance and insulin resistance in obese adolescents

BACKGROUND/OBJECTIVES

Adult studies suggest that intra-hepatic fat predicts 2-h blood glucose levels and type 2 diabetes, and may have a role in the development of insulin resistance. Our study objective was to explore relationships between intra-hepatic fat and (i) blood glucose levels and (ii) insulin resistance determined by homeostasis model assessment (HOMA) in a group of obese adolescents.

METHODS

Subjects were 61 obese non-diabetic male and female volunteers aged 12-18 years inclusive with a body mass index >95th percentile for age and 2-h blood glucose <200 mg dL(-1) . Each subject underwent 2-h glucose tolerance testing and measurement of haemoglobin A1c, ultrasensitive C-reactive protein and fasting insulin. Visceral, subcutaneous abdominal and intra-hepatic fat were determined by magnetic resonance imaging. Intra-hepatic fat was measured by gradient echo chemical shift imaging.

RESULTS

Alanine aminotransferase levels and hepatic phase difference were not significant correlates of fasting or 2-h glucose. In a multiple regression model including hepatic phase difference and visceral fat volume, visceral fat volume was the sole predictor of HOMA.

CONCLUSIONS

This study provides no support to the notion that intra-hepatic fat has a role in the regulation of fasting blood glucose, 2-h postprandial blood glucose or systemic insulin resistance.

Influence of the Kidney Histology at the Time of Donation on Long Term Kidney Function in Living Kidney Donors

Living donation is the best choice for kidney transplantation, obtaining long-lasting good results for the recipient. Some concern still remains regarding the donor's long-term health. Kidney biopsy was routinely performed in our donor population at the time of donation many years ago. We found the existence of morphological kidney disease in those samples, in spite of normal clinical evaluations before donation. We attempted to correlate those abnormalities with long-term clinical outcomes. Donors were at least 10 years after surgery. A medical interview, including the SF-36 Health Survey, laboratory evaluation, and ambulatory blood pressure monitoring was performed on 27 donors meeting the inclusion criteria. Two donors had died after donation from unrelated causes with no known nephropathy. Histological analysis showed abnormalities in 16 of 29 donors. We found an increased prevalence of hypertension compared to the general population. Interestingly, there was no proteinuria in the donor population, and none developed clinical nephropathy. All subjects felt emotionally rewarded with donation, stating that their lives had no limitations. Our results suggest that kidney biopsy is neither necessary nor useful prior to donation because, although many donors had morphological kidney disease, none developed clinical nephropathy in the long term.

Identification and functional characterization of a novel ryanodine receptor mutation causing malignant hyperthermia in North American and South American families

Malignant hyperthermia is a pharmacogenetic disorder associated with mutations in Ca(2+) regulatory proteins. It manifests as a hypermetabolic crisis triggered by commonly used anesthetics. Malignant hyperthermia susceptibility is a dominantly inherited predisposition to malignant hyperthermia that can be diagnosed by using caffeine/halothane contracture tests. In a multigenerational North American family with a severe form of malignant hyperthermia that has caused four deaths, a novel RYR1 A2350T missense mutation was identified in all individuals testing positive for malignant hyperthermia susceptibility. The same A2350T mutation was identified in an Argentinean family with two known fatal MH reactions. Functional analysis in HEK-293 cells revealed an altered Ca(2+) dependence and increased caffeine sensitivity of the expressed mutant protein thus confirming the pathogenic potential of the RYR1 A2350T mutation.

North American malignant hyperthermia population: screening of the ryanodine receptor gene and identification of novel mutations

BACKGROUND

Malignant hyperthermia (MH) is a disorder of skeletal muscle manifested as a life-threatening hypermetabolic crisis in susceptible individuals after exposure to inhalational anesthetics and depolarizing muscle relaxants. Mutations in the gene encoding the skeletal muscle ryanodine receptor (RYR1) are considered a common cause of the disorder, and, to date, more than 20 RYR1 mutations have been reported in European and Canadian families. Some studies suggest that differences may exist in the frequencies and distribution of mutations in the RYR1 gene between European and North American MH families the frequency and distribution of mutations in the RYR1 gene.

METHODS

Skeletal muscle samples from 73 unrelated individuals diagnosed as MH susceptible according to the North American MH caffeine-halothane contracture test were studied. Genomic DNA of MH-susceptible patients was investigated by polymerase chain reaction-based restriction fragment length polymorphism, single-strand conformation polymorphism, and sequencing analysis. The majority of known RYR1 mutations were analyzed using the restriction fragment length polymorphism method, whereas new mutations were searched by single-strand conformation polymorphism in exons 12, 15, 39, 40, 44, 45, and 46 of the gene.

RESULTS

Seven known RYR1 mutations (Arg163Cys, Gly248Arg, Arg614Cys, Val2168Met, Thr2206Met, Gly2434Arg, and Arg2454His) were detected at frequencies of 2.7, 1.4, 1.4, 1.4, 1.4, 5.5, and 4.1%, respectively. In addition, three novel amino acid substitutions (Val2214Ile, Ala2367Thr, and Asp2431Asn) were detected at frequency of 1.4% each. These 10 mutations account for 21.9% of the North American MH-susceptible population.

CONCLUSION

Three novel candidate mutations in the RYR1 gene were identified in these MH patients. The frequency and distribution of RYR1 mutations observed in this North American MH population was markedly different from that previously identified in Europe. Larger-scale studies are necessary to clarify the type and frequency of mutations in RYR1 associated with MH in North American families.

Two surgeons who popularized spinal anesthesia

Because of the significant mortality associated with general anesthesia in the early decades of the 20th century, two US surgeons--George Pitkin and Wayne Babcock--suggested suitable alternatives. Believing in the greater manageability and safety of regional and spinal anesthesia, each investigated these techniques, employing them for surgery and went on to popularize the rational use of regional anesthesia. Reg Anesth Pain Med 2001;26:278-282.

Identification of the Arg1086His mutation in the alpha subunit of the voltage-dependent calcium channel (CACNA1S) in a North American family with malignant hyperthermia

Individuals from a large North American population were screened for the presence of the mutation in the alpha1 subunit of the voltage-dependent calcium channel (CACNA1S) that has recently been associated with malignant hyperthermia (MH). This Arg1086His mutation was screened for in 154 MH normal (MHN) individuals and 112 MH susceptible (MHS) individuals, who were diagnosed by the North American protocol of the in vitro contracture test. PCR and restriction enzyme analysis was used to test for the mutation. The Arg1086His mutation in the CACNA1S was not found in any of the MHN individuals. In contrast, two related individuals (grandfather and grandson, father and son of the MH proband) among the MHS group exhibited this mutation. However, a third MHS individual in the same family (granddaughter, cousin of the grandson) did not exhibit this mutation. These results indicate that this mutation may be associated with MH in this family. Genetic alterations in the CACNA1S associated with MH are present in approximately 1% of this North American MHS population.

[Metachronous pancreatic metastasis of a renal cell carcinoma. 3 new cases]

We report two males and one female, aged 71, 81 and 73 years old respectively, previously operated of a renal cell carcinoma. During the follow up of the 71 years old male, the CAT scan showed three lesions in the pancreas. Also, the CAT scan in the female showed one lesion in the tail of the pancreas. The 81 years old male was admitted to the emergency room due to a upper gastrointestinal bleeding. Endoscopy showed a proliferating lesion in the second portion of the duodenum whose biopsy showed a clear cell carcinoma. The CAT scan showed also a tumoral mass in the head of the pancreas. All three patients were subjected to surgical resection of the tumors without postoperative complications or mortality.

[Apoplexy in pituitary metastasis of renal cell carcinoma. Clinical case followed for 7 years]

We report a man in whom a 15 cm. renal tumor was excised at the age of 49. The pathological examination showed a clear cell carcinoma. Five years later, he presented with headache, vomiting and unilateral palpebral ptosis. Imaging studies showed a sellar tumor with pituitary apoplexy. The tumor was excised and the pathological study disclosed a clear cell tumor, positive for vimentin, cytokeratins AE1 and AE3 and immunohistochemically negative for LH, TSH, ACTH and GH. Considering the similar histopathological features, it was considered as a metastasis of the renal tumor. The patient was supplemented with thyroid, adrenal and gonadal hormones. Seven years later, he presented a new tumor in the remaining kidney, that corresponded to a cystic papillary renal cell carcinoma. Afterwards, he presented a transitional urinary bladder tumor. Mortality associated to renal cell tumors is 90% at 5 years, and pituitary metastases are extraordinarily uncommon.

Attenuated nontoxinogenic and nonencapsulated recombinant Bacillus anthracis spore vaccines protect against anthrax

Several highly attenuated spore-forming nontoxinogenic and nonencapsulated Bacillus anthracis vaccines differing in levels of expression of recombinant protective antigen (rPA) were constructed. Biochemical analyses (including electrospray mass spectroscopy and N terminus amino acid sequencing) as well as biological and immunological tests demonstrated that the rPA retains the characteristics of native PA. A single immunization of guinea pigs with 5 x 10(7) spores of one of these recombinant strains, MASC-10, expressing high levels of rPA (>/=100 microgram/ml) from a constitutive heterologous promoter induced high titers of neutralizing anti-PA antibodies. This immune response was long lasting (at least 12 months) and provided protection against a lethal challenge of virulent (Vollum) anthrax spores. The recombinant B. anthracis spore vaccine appears to be more efficacious than the vegetative cell vaccine. Furthermore, while results clearly suggest a direct correlation between the level of expression of PA and the potency of the vaccine, they also suggest that some B. anthracis spore-associated antigen(s) may contribute in a significant manner to protective immunity.

[Rethinking social protection in health in Latin America and the Caribbean]

Despite what is written in the constitutions and other basic document mandates of the countries of the Region, exclusion from social protection in health (SPH) affects an important proportion of the population (at least 20%, which represents, in absolute figures, between 80 and 200 million people). These estimates are obtained through a series of theoretical (social security coverage) and practical indicators that encompass structural indicators (poverty, ethnicity, and geographical barriers) as well as process indicators (non-institutional births, compliance with vaccination schedules, and access to basic sanitation). Exclusion levels in a society are affected by the degree of segmentation of the health system. Traditionally, most countries of the Region have had a public, a social security and a private subsystem in health. Lack of attention to the problem has resulted in the formation of a community-based subsystem. The coexistence of many subsystems, along with poor regulation on the part of health authorities, has resulted in high levels of exclusion and inefficient resource allocation within the sector. The organization of social dialogue processes focusing on SPH within the context of health sector reform initiatives in each country is recommended. The process, which should be participatory, should include a full diagnosis of the situation (how many are excluded, who are they, and why, and what mechanisms are the most appropriate for tackling the issue in each country). It should also provide a political and technical feasibility analysis of the most suitable options for each society, and a determination of whether or not conventional subsystems have exhausted their potential. The process should culminate in a program for implementing the specific proposals made in each society, in an effort to maximize SPH.

Influence of dose and beverage type instructions on alcohol outcome expectancies of DUI offenders

OBJECTIVE

To test the hypothesis that self-reported alcohol outcome expectancies are situationally specific beliefs that vary depending on contextual variables, such as the quantity and type of beverage one is instructed to imagine consuming.

METHOD

One hundred thirty DUI offenders attending a 72-hour weekend program were randomly assigned to either a "small dose" or "large dose" instruction condition and then completed five versions of the Comprehensive Effects of Alcohol scale, a separate version for each of five beverage types ("alcohol," "beer," "wine," "mixed drinks" and "straight liquor").

RESULTS

Two separate 2 (dose) x 5 (beverage type) ANOVAs revealed that positive and negative expectancies varied significantly as a function of both dose and beverage type. Specifically, participants endorsed more positive outcomes and more negative outcomes when they imagined drinking a large amount versus a small amount. In addition, participants endorsed significantly more positive expectancies for beer and mixed drinks than for wine. They endorsed the largest number of negative expectancies for straight liquor and the fewest for wine.

CONCLUSIONS

Expectancies are to some degree context-bound and researchers and clinicians should consider providing explicit dose and beverage type instructions to research participants and clients when they use self-report questionnaires to assess alcohol outcome expectancies.

Catastrophic antiphospholipid syndrome associated with crescentic glomerulonephritis: a clinicopathologic case

The association of renal failure with catastrophic antiphospholipid syndrome has been reported in the context of microvascular occlusions and/or malignant hypertension. We describe a 36-year-old woman who died of multiorgan failure with the laboratory, clinical and histopathological characteristics of catastrophic antiphospholipid syndrome associated with a crescentic glomerulonephritis and renal failure.

Assessing and training recognition of intoxication by university students

Forty-five undergraduate volunteers attended either a 2-session recognition of intoxication training program or a 2-session attention-placebo control group. Stimulus videotapes portrayed male and female university students (targets) performing various tasks both before drinking and again after consumption of 3 to 5 standard drinks. Participants' accuracy in recognizing whether videotaped targets had or had not been drinking (target status) was assessed 1 week posttraining and 2 months posttraining. At the 1-week follow-up assessment, participants in the training program had a higher mean number of accurate ratings of target status compared with the attention-placebo control group. In addition, a larger proportion of training-group participants expressed an overall preference to rate a target as not having been drinking if they were unsure of target status. These effects were not maintained at the 2-month follow-up assessment.

Understanding the relation between expectancies and drinking among DUI offenders using expectancy categories

OBJECTIVE

In the context of several recent studies that have found negative expectancies to predict drinking-related variables, the present study was designed to examine the relationships among positive expectancies, negative expectancies and drinking, in a sample of DUI offenders.

METHOD

Participants (N = 96; 75% male) recruited from a 3-day residential alcohol education program completed a demographic data sheet, the Negative Alcohol Expectancy Questionnaire (NAEQ), the Alcohol Expectancy Questionnaire (AEQ) and the Customary Drinking Record upon admission to treatment. At a 3-month follow-up assessment, these measures were re-administered to 49% of the sample.

RESULTS

Hierarchical multiple regression revealed that both positive and negative expectancies were related to number of drinks in the previous 30 days. Stepwise multiple regression revealed that baseline drinking and negative expectancies were both related to number of drinking days at the 3-month follow-up assessment. To assess the interplay of positive and negative expectancies as they relate to drinking, participants were categorized as "low" or "high" on both the AEQ and the NAEQ. The low positive/low negative group drank more than the low positive/high negative group. There was no statistically significant difference in drinking between the high positive/low negative and the high positive/high negative group.

CONCLUSIONS

This study provides additional evidence that negative alcohol expectancies are related to drinking. These findings suggest that the proposed restraining influence of negative expectancies on drinking may be reduced when a drinker has concurrent positive expectancies which are high.

Assessment of university students' coping strategies and reasons for driving in high-risk drinking-driving situations

A total of 116 students (87 women; 29 men) enrolled at a large, public Midwestern university in the United States were recruited to complete a set of demographic questionnaires and drinking-driving episode surveys. The latter surveys assessed participants' reported motivations for driving or not driving during four recent drinking episodes. Content analyses were used to develop lists of commonly reported reasons for not driving (e.g. found alternate transportation), reasons for driving after drinking (e.g. perceived need to go to destination), potential alternatives to driving after drinking (e.g. walking to destination), and strategies used to avoid detection or arrest by police (e.g. driving more slowly, using back roads or side streets). Participants made both situational and self-coping attributions to explain why they did not, on occasion, drive after drinking. These results may be used as a foundation for prevention and education programs that are designed to: (a) encourage use of coping strategies and alternatives to driving while disputing peer-generated justifications for driving after drinking, and (b) challenge the value of potentially unsafe strategies for avoiding detection and arrest when driving under the influence.

Simple intratesticular cysts in children: preoperative sonographic diagnosis and histological correlation

BACKGROUND

Simple intratesticular cysts are rare in children and have been considered the most uncommon cause of scrotal cystic masses in this age group. The exact etiology of these lesions is still unclear. High-resolution ultrasonography has been proved to be a reliable and accurate imaging modality in the evaluation of scrotal abnormalities in children.

PATIENTS AND METHODS

We report the sonographic findings in five boys aged from 4 to 10 months who presented with a scrotal mass and had a simple intratesticular cyst. Ultrasonography showed that all of them displayed a characteristic appearance and provided the necessary information to perform conservative surgery, with testicular preservation in four infants. In one infant, the cyst involved most of the testis, and an orchiectomy was performed.

RESULTS

Pathological examination revealed a single smooth-walled cystic structure, with clear and serous fluid, lined with flattened epithelial cells in all of the infants.

CONCLUSION

Our findings appear to support the hypothesis that these cysts could correspond to mesothelial inclusions. Sonographically, differential diagnosis should include mainly epidermoid cysts of the testis, which are mostly cystic but characteristically contain some echoes within them, in contrast to simple cysts and cysts of the tunica albuginea, which lie outside the testicular parenchyma.

ATX II, a sodium channel toxin, sensitizes skeletal muscle to halothane, caffeine, and ryanodine

BACKGROUND

The function or expression of subtypes of the sodium ion (Na+) channel is altered in biopsies or cultures of skeletal muscle from many persons who are susceptible to malignant hyperthermia (MH). ATX II, a specific Na+ channel toxin from a sea anemone, causes delayed inactivation of the channel similar to that seen in cell cultures of MH muscle. ATX II was added to skeletal muscle to determine whether altered Na+ channel function could increase the sensitivity of normal skeletal muscle to agents (halothane, caffeine, ryanodine) to which MH muscle is hypersensitive.

METHODS

Studies were performed of fiber bundles from the vastus lateralis muscle of persons who were deemed not MH susceptible (MH-) or MH susceptible (MH+) according to the MH diagnostic test and of strips of diaphragm muscle from rats. Preparations in a tissue bath containing Krebs solution were connected to a force transducer. ATX II was introduced 5 min before halothane, caffeine, or ryanodine.

RESULTS

ATX II increased the magnitude of contracture to halothane in preparations from most MH-, but not MH+, human participants. After ATX II treatment, preparations from 9 of 24 MH- participants generated contractures to halothane, 3%, that were of the same magnitude as those from MH+ participants. Preparations from four of six ATX II-treated healthy participants also gave responses of the same magnitude as those of MH-susceptible participants to a graded halothane challenge (0.5-3%). The contractures to bolus doses of halothane in specimens from male participants were more than three times larger than the contractures in specimens from female participants. In rat muscle, ATX II increased the magnitude of contracture to caffeine (2 mM) and decreased the time to produce a 1-g contracture to ryanodine (1 microM).

CONCLUSIONS

ATX II, which causes delayed inactivation of the Na+ channel in cell cultures similar to that reported in cultures of MH+ skeletal muscle, increased the sensitivity of normal muscle to three agents to which MH+ muscle is hypersensitive. The increased sensitivity to halothane, 3%, occurred in most (79%), but not all, MH- participants, and this effect was most evident in male participants. Therefore, abnormal function of the Na+ channel, even if it is a secondary event in MH, may contribute to a positive contracture test result for MH.

Comparison of European and North American malignant hyperthermia diagnostic protocol outcomes for use in genetic studies

BACKGROUND

Halothane and caffeine diagnostic protocols and an experimental ryanodine test from the North American Malignant Hyperthermia (MH) Group (NAMHG) and the European MH Group (EMHG) have not been compared in the same persons until now.

METHODS

The outcomes of the NAMHG and EMHG halothane and caffeine contracture tests were compared in 84 persons referred for diagnostic testing. In addition, the authors assessed the experimental ryanodine protocol in 50 of these persons.

RESULTS

Although the NAMHG and EMHG halothane protocols are slightly different methodologically, each yielded outcomes in close (84-100%) agreement with diagnoses made by the other protocol. Excluding 23 persons judged to be equivocal (marginally positive responders) by the EMHG protocol resulted in fewer persons classified as normal and MH susceptible (42 and 19, respectively) than those classified by the NAMHG protocol (48 and 34, respectively). For the 61 persons not excluded as equivocal, the diagnoses were identical by both protocols, with the exception of one person who was diagnosed as MH susceptible by the NAMHG protocol and as "normal" by the EMHG protocol. The NAMHG protocol produced only two equivocal diagnoses. Therefore, a normal or MH diagnosis by the NAMHG protocol was frequently associated with an equivocal diagnosis by the EMHG protocol. The time to 0.2-g contracture after the addition of 1 microM ryanodine completely separated populations, which was in agreement with the EMHG protocol and, except for one person, with the NAMHG protocol.

CONCLUSIONS

Overall, the NAMHG and EMHG protocols and the experimental ryanodine test yielded similar diagnoses. The EMHG protocol reduced the number of marginal responders in the final analysis, which may make the remaining diagnoses slightly more accurate for use in genetic studies.

Failure to identify the ryanodine receptor G1021A mutation in a large North American population with malignant hyperthermia

Anesthesia-induced malignant hyperthermia (MH) is a rare inherited disorder of skeletal muscle. Several mutations in the ryanodine receptor (RYR1) have been found to be causative of MH. The G1021A mutation in the RYR1 is one of the most frequently occurring mutations in European populations. MH normal (165) and MH susceptible (114) North American patients were screened for the presence of the G1021A mutation. This mutation was not found in any of the patients tested. These studies support the absence of this mutation in the normal population. Furthermore, these findings emphasize the importance of viewing the distribution of MH mutations as variable gene pools with frequencies dependent on the geographical location of the population examined.

The assessment of young children's expectancies of alcohol versus a control substance

AIMS

The chief purpose of the current study was to assess whether young children endorse expectancies specific to alcohol.

DESIGN

In order to accomplish this aim, a 2 (gender of child) by 2 (gender of adult drinker) by 2 (grade level) by 2 (beverage type) repeated measure design was employed with beverage type as the repeated measure.

SETTING

Data were collected within elementary schools located in two Midwestern states.

PARTICIPANTS

One hundred and twenty-four second and third graders (42% male) participated in individually structured interviews.

MEASUREMENTS

The expectancy interview was based on the Children's Alcohol-Related Expectancy Questionnaire and assessed each child's beliefs about the desirable and undesirable consequences which adult men and women might experience after drinking alcohol (beer) and a control beverage (iced tea).

FINDINGS

The results indicated that children endorsed significantly more undesirable expectancies for beer than for iced tea, and more desirable expectancies for iced tea than for beer. In addition, children's expectancies varied as a function of the gender of the drinker. Specifically, both second- and third-graders expected more undesirable outcomes for women than for men, and second graders expected fewer desirable outcomes for women than for men, regardless of beverage.

CONCLUSIONS

Prior to substantial experience with alcohol consumption, children have already developed expectancies for alcohol. Specifically, young elementary children endorse predominantly undesirable expectancies for beer.

The laryngeal mask airway reliably provides rescue ventilation in cases of unanticipated difficult tracheal intubation along with difficult mask ventilation

In 1995, our department of anesthesiology established an airway team to assist in treating unanticipated difficult endotracheal intubations and an airway quality improvement (QI) form to document the use of emergency airway techniques in airway crises (laryngeal mask airway [LMA], flexible fiberoptic bronchoscopy, retrograde intubation [RI], transtracheal jet ventilation [TTJV], and cricothyrotomy). Over a 2-yr period, team members and staff anesthesiologists completed airway QI forms to document the smallest peripheral SpO2 during an airway crisis, the number of direct laryngoscopies (DL) performed before using an emergency airway technique, and the emergency airway technique that succeeded in rescue ventilation. Team members agreed to use the LMA as the first emergency airway technique to treat the difficult ventilation/difficult intubation scenario. A SpO2 value < or =90% during mask ventilation defined difficult ventilation. Inability to perform tracheal intubation by DL defined difficult intubation. An increase in the SpO2 value >90% defined rescue ventilation. Review of airway QI forms from October 1, 1995 until October 1, 1997 revealed 25 cases of difficult ventilation/difficult intubation. Before airway rescue, the median SpO2 was 80% (range 50%-90%), and there were four median attempts at DL (range one to nine). The LMA had a success rate of 94% (95% confidence interval [CI] 77-100). Flexible fiberoptic bronchoscopy, TTJV, RI, and surgical cricothyrotomy had success rates of 50% (95% CI 0-100), 33% (95% CI 0-100), 100% (95% CI 37-100), and 100% (95% CI 37-100), respectively. LMA insertion as the first alternative airway technique was useful in dealing with unanticipated instances of simultaneous difficulty with mask ventilation and tracheal intubation.

IMPLICATIONS

Twenty-five cases of simultaneous difficulty with mask ventilation and tracheal intubation occurred after the induction of general anesthesia during the study period. The laryngeal mask was used in 17 cases, and it provided rescue ventilation without complication in 94% of these cases (95% confidence interval 77-100).

Screening college students for alcohol problems: psychometric assessment of the SASSI-2. Substance Abuse Subtle Screening Inventory

OBJECTIVE

This study examined the psychometric properties of the Substance Abuse Subtle Screening Inventory (SASSI-2) with college students.

METHOD

The first part of the study examined the test-retest reliability of the SASSI-2 at 2-week (n = 55) and 4-week (n = 47) intervals with students recruited from introductory psychology courses. The second part used a new sample of 164 college students to assess the internal consistency of the SASSI-2 subscales, the relationship of the SASSI-2 with other common alcohol screening instruments, and its reactivity to response biases. Participants completed the SASSI-2 under standard instructions, or instructions to minimize any alcohol problems they might have (fake good), or to exaggerate any alcohol problems they might have (fake bad). They then completed the CAGE, MAC and MAST under those measures' standard instructions.

RESULTS

The 2-week and 4-week test-retest reliability of the SASSI-2 subscales was moderate to high, but the test-retest reliability for overall classification as "chemically dependent" or "non-chemically dependent" was moderate at 2 weeks and relatively poor at 4 weeks. Internal consistencies for the SASSI-2 subscales ranged from poor to strong (Cronbach alphas ranging from .11 to .93), and the SASSI-2 drinker classification status correlated moderately with drinker classifications based on the CAGE, MAC and MAST. There was no difference in the proportion of participants classified as "chemically dependent" on the SASSI-2 when instructed to "fake good" and under standard instructions, but college students scored as "chemically dependent" more frequently when instructed to "fake bad."

CONCLUSIONS

When the SASSI-2 is used with college students, its reliability and validity are comparable to other instruments that currently exist in the public domain. The vulnerability of the SASSI-2 to intentional faking warrants further investigation.

Emboli observed with use of transesophageal echocardiography immediately after tourniquet release during total knee arthroplasty with cement

The right atrium and the right ventricle of fifty-five patients were imaged with transesophageal echocardiography during fifty-nine total knee arthroplasties performed with cement and the use of general anesthesia. The patients ranged in age from thirty-two to eighty-three years (mean, 65.5 years). Cardiopulmonary parameters were measured with use of hemodynamic monitoring systems, such as pulse oximeters, pulmonary artery catheters, and radial artery catheters. In addition, a femoral vein catheter was inserted on the side of the operation in ten of the fifty-five patients. Showers of echogenic material traversing the right atrium, the right ventricle, and the pulmonary artery after the tourniquet was deflated were observed to various degrees in all patients and lasted three to fifteen minutes. The mean peak intensity occurred within thirty seconds (range, twenty-four to forty-five seconds) after the tourniquet was released. The mean mixed venous oxygen saturation (and standard error of the mean) decreased (from 83+/-0.9 to 72+/-1.5 per cent) and the mean pulmonary arterial pressure increased (from 20+/-1.0 to 27+/-1.0 millimeters of mercury [2.67+/-0.13 to 3.60+/-0.13 kilopascals]), compared with the values before the tourniquet was released, in all patients. The pulmonary vascular resistance index increased after release of the tourniquet (to a maximum of 328+/-29 dyne.s.cm(-5).m2; p = 0.00002) only in the patients who had echogenic material that was at least 0.5 centimeter in diameter. Clinical pulmonary embolism developed postoperatively in three patients; all three had had echogenic particles that were more than 0.5 centimeter in maximum diameter on imaging. Blood aspirated from one of the pulmonary artery catheters and from five of the ten femoral vein catheters demonstrated fresh venous thrombus. Histological evaluation of the aspirates failed to demonstrate fat, marrow, or particles of polymethylmethacrylate. Surgeons should consider acute pulmonary embolism as a diagnosis when evaluating a patient who has hemodynamic collapse during total knee arthroplasty performed with cement.

Sodium channel in human malignant hyperthermia

BACKGROUND

The abundance of a specific sodium channel subunit (SkM2) appeared to be altered in vitro in cell cultures from persons susceptible to malignant hyperthermia. This study sought to determine whether these findings are artifacts of cell culture or whether they may be relevant to malignant hyperthermia.

METHODS

Regulation of transcript levels of SkM2, a specific sodium channel alpha-subunit, was determined by mRNA analysis. Functional SkM2 protein was estimated in biopsy sections of vastus lateralis muscle by inhibiting the directly elicited muscle twitch by tetrodotoxin, which can differentiate at least three sodium currents in skeletal muscle.

RESULTS

The transcript levels of SkM2 were depressed by 115-fold in six of seven persons susceptible to malignant hyperthermia; and the functional expression of the SkM2 protein, based on the tetrodotoxin sensitivity of the directly elicited twitch, was decreased by at least fourfold in muscle from persons susceptible to malignant hyperthermia compared with persons who were not susceptible.

CONCLUSIONS

As in previous studies in cell culture, altered mRNA and/or the functional expression of a specific subunit of the sodium channel (SkM2) was found in biopsy sections of muscle from all 12 persons examined who were susceptible to malignant hyperthermia but in none of the 16 nonsusceptible participants. Human malignant hyperthermia is a heterogeneous disorder, and the down-regulation of SkM2 may be involved in the final common pathway through which mutations in any one of several proteins, including the ryanodine receptor, could render a person susceptible.

Antagonism of suxamethonium-induced jaw muscle contracture in rats

Masseter muscle rigidity (MMR) induced during general anaesthesia by suxamethonium is a clinical problem that may interfere with tracheal intubation. We have investigated the relation between twitch tension and contracture response to suxamethonium in rats. Rats were anaesthetized with 1% halothane (1.35 MAC). Jaw muscle temperature was maintained at either 37 or 41 degrees C while rectal temperature was kept at 37 degrees C by radiant heat. Twitch tension was produced by nerve stimulation at 0.2 Hz. Rats were pretreated with either a low dose of vecuronium (0.03 mg kg-1) or dantrolene (0.8 mg kg-1). Thereafter suxamethonium 750 micrograms kg-1 was administrated i.v. Low-dose vecuronium pretreatment significantly (90%) decreased suxamethonium-induced jaw muscle contracture (JMC) with minimal (3%) twitch block during local hyperthermia. Low-dose dantrolene pretreatment also reduced JMC (81% at 37 degrees C and 82% at 41 degrees C) while decreasing twitch by 30% at 37 degrees C and 31% at 41 degrees C. Both vecuronium and dantrolene at doses that minimally depressed the twitch response antagonized suxamethonium-induced JMC. We speculate that pretreatment with low-dose vecuronium decreases suxamethonium-induced MMR clinically.

Hyperkalemic cardiac arrest during anesthesia in infants and children with occult myopathies

In 1992, the Malignant Hyperthermia Association of the United States and The North American Malignant Hyperthermia Registry received reports of cardiac arrest in apparently healthy children given succinylcholine. Using data from 1990 to 1993, this study analyzes: (1) etiology of all reported pediatric arrests and (2) whether survival was associated with certain patient or treatment variables. We reviewed retrospectively all reports of pediatric (age < 18 years) arrests occurring within 24 hours of anesthesia. Etiology of arrests and presence of myopathy were determined. Twenty-five patients (92% male, median 45 months old) arrested; 23/25 (92%) were scheduled for minor surgery. Before receiving a potent inhalational anesthetic (92%) and/or succinylcholine (72%), these patients were evaluated by the anesthesiologist as being healthy with no personal or family history of myopathy. Serum potassium during arrest was measured in 18/25 (72%) patients; hyperkalemia (mean [K+] = 7.4 +/- 2.8, median 7.5 mmol/L) was detected in 13/18 (72%) patients. Postarrest resuscitations lasted a median of 42 minutes (range 10-296). Ten (40%) patients died, 1 (4%) is vegetative, and 14 (56%) returned to baseline neurologic function. A previously unrecognized Duchenne dystrophy (n = 8) or unspecified myopathy (n = 4) was diagnosed in 12 (48%) patients. Eight of these 12 patients' arrests were associated with hyperkalemia. Ten (40%) patients had no postarrest evaluation to exclude occult myopathy. No patient or treatment variables were statistically associated with survival. We conclude that, whenever possible, pediatricians should evaluate their patients (especially male infants and children) preoperatively for the presence of occult myopathy. During perianesthetic resuscitations, the pediatric advanced life support protocol should be modified to detect and treat hyperkalemia, a potentially reversible state even after prolonged resuscitation efforts. Following anesthetic deaths, pathologists should examine body fluid electrolytes and skeletal muscle for myopathy and dystrophin. If a preanesthetic creatine kinase screen for myopathy in male patients and restrictions on succinylcholine had been used, 64% of arrests and 60% of deaths might have been prevented. A formal prospective risk/benefit analysis for preventive measures is needed.

Malignant struma ovarii. A case report and review of the literature

Malignant struma ovarii is a rare form of ovarian carcinoma; only 3 cases of its pure papillary type have been reported in the literature. A new case of malignant papillary struma ovarii arising in an asymptomatic 32-year-old woman is presented. Due to its rarity, there has been confusion in the diagnosis and management of malignant struma ovarii. Criteria for the diagnosis of malignant papillary struma ovarii are proposed. Conservative treatment after a complete staging procedure is possible due to the usually benign course and low incidence of metastases of this tumor.

Recreational drug use concurrent with abuse or dependence on other psychoactive substances

In an effort to identify instances of the non-problematic use of a drug concurrent with the problematic use of one or more other drugs, we used structured interviews to obtain comprehensive drug use histories from 48 clients admitted to an intensive outpatient program. We classified clients on the basis of whether they demonstrated evidence of concurrent problematic and non-problematic drug use (Index and Probable Index cases) or only problematic drug use patterns (Non-Index cases). Both Index and Non-Index drug use patterns were about equally common in our sample. Both Index and Probable Index cases used a variety of drugs in a non-problematic manner and were generally congruent in their self-labelling of their drug use relative to their DSM-IV status for each drug used. We discuss several limitations of the study, including our reliance on retrospective, self-report data; potential problems with generalization to other populations; and possible changes in drug use patterns over time.

Acceptance of moderate drinking by alcoholism treatment services in Canada

OBJECTIVE

The present study was conducted to provide a nationwide survey of acceptance of nonabstinence goals and related alcoholism treatment practices by Canadian alcoholism treatment services.

METHOD

A random sample of 335 Canadian alcoholism treatment service agencies were mailed a 4-page questionnaire designed to assess acceptance of moderate drinking as a drinking goal and related alcoholism treatment practices.

RESULTS

Acceptance varied by type of service, with considerably more acceptance by outpatient programs (62%) and mixed inpatient/outpatient programs (43%) than inpatient/detoxification/ correctional facilities (27%) and halfway houses (16%). Two-thirds of the respondents who reported moderate drinking as unacceptable in their own agencies categorically rejected moderation for all alcoholism clients.

CONCLUSIONS

Individuals seeking services in Canadian alcoholism treatment agencies are more likely to have a choice of drinking goals if they present to an outpatient program than a residential institution, and Canadian agencies appear more accepting of moderation goals than American programs, but less accepting than British and Norwegian service agencies.

Altered sodium current response to intracellular fatty acids in halothane-hypersensitive skeletal muscle

Biopsies of human skeletal muscle were analyzed by an in vitro contracture test (IVCT) for responsiveness to a halothane challenge: noncontracting (nonresponsive; IVCT-) and contracting (IVCT+). A muscle biopsy that is IVCT+ indicates potential malignant hyperthermia (MH) susceptibility. Primary cultures were grown from portions of the skeletal muscle biopsies, and voltage-activated currents were measured by whole cell recording in the presence or absence of 2-5 microM intracellular arachidonic or oleic acids. In untreated IVCT- cells, Na+ currents were predominantly tetrodotoxin (TTX) insensitive, indicating that most of the current was carried through the embryonic SkM2 isoform of the Na+ channel. Inclusion of fatty acids in the recording pipette of IVCT- cells produced an increase in voltage-activated Na+ currents during 20 min of recording. Approximately 70% of currents in fatty acid-treated cells were TTX sensitive, indicating activation of the adult SkM1 isoform of the Na+ channel. In contrast to IVCT- cells, IVCT+ cells expressed Na+ currents that were predominantly TTX sensitive even in the absence of added fatty acid, thus showing a relatively large baseline functional expression of SkM1 channels. Addition of fatty acids to the recording pipette produced little further change in the magnitude or TTX sensitivity of the whole cell currents in IVCT+ cells, suggesting altered functional regulation of Na+ channels in MH muscle.

Microscopic analysis of the tips of thin spinal needles after subarachnoid puncture

BACKGROUND AND OBJECTIVES

Foreign material may pass unrecognized with the spinal needle into the subarachnoid space. Therefore the tips of three clinically used types of spinal needles--Quincke (27-gauge), two-zone bevel (26-gauge), and Sprotte or pencil point (27-gauge)--were prepared for microscopic analysis after subarachnoid puncture in human cadavers.

METHODS

Three cadavers were placed in the lateral position, the backs were scrubbed with disinfectant solution containing 0.1% fluorescein, and 12 needles of each type (half of them through an introducer) were inserted via interspaces L2-L5 into the subarachnoid space. Under visual control (spinal canal opened), the needle tips were cut and collected for fluorescence microscopy. Another eight needles of each type (half through an introducer) were inserted, the tips were collected into tubes filled with physiologic saline, and cytocentrifuged smears of the eluted material were made.

RESULTS

On microscopy, only one of the two-zone bevel needles and two of the pencil point needles, placed through an introducer, were without attachments. All the others had variable amounts of fluorescence, and visible tissue particles adhered to the tip. The largest particles appeared on two of the Quincke needle tips. Bent tips were seen on 7 of the 12 two-zone bevel needles. The Quincke group had two and the pencil point group no bent needle tips. Clusters of epithelioid cells were seen in the cytocentrifugation smears of Quincke and two-zone bevel needle tips, but only very few cellular clusters were seen in the smears from the pencil point needle tips.

CONCLUSIONS

Of the three needle types studied, the pencil point type has a tip that best withstands distortion and adherence of foreign material during experimental subarachnoid puncture.

The elderly and the use of illicit drugs: sociological and epidemiological considerations

Debates over the prevalence of elderly illicit drug addicts in the population divert our attention from this group as a viable study population. Due to their decelerated lifestyle, low crime rates, and our attitudes toward the elderly as nonstreet drug users, they are likely to remain hidden from the public eye. This paper reviews past trends in drug misuse among the elderly, the lifestyle of those addicted to drugs, the complications associated with drug misuse and aging, and the problems that the elderly face with traditional treatment programs. Given our aging society, is the study of elderly street addicts and users an important area of concern?

Follow-up study of anonymous ovum donors

A follow-up study was conducted to determine the emotional and medical responses of anonymous ovum donors to participation in an ovum donation procedure. Medically, donors reported significant discomfort, particularly relating to bloating, immediately prior to retrieval and for a brief period following retrieval. However, donors indicated that these effects no longer persisted at the time of follow-up. They also mentioned how unusual and initially anxiety-arousing it was to be in charge of their own injections. Few donors reported serious adverse emotional responses; many reported positive emotional responses to participation. Donors felt proud of their contribution, talked about their participation with friends and relatives, would be willing to participate again and would recommend ovum donation to other women. However, since the sample included only 43% of the 74 women who donated, caution is necessary in generalizing from the results of our study.

The incidence of venous emboli during extramedullary guided total knee arthroplasty

During total knee arthroplasty (TKA), instrumentation of the marrow cavity with an intramedullary guide appears responsible for fatal intraoperative pulmonary embolism. Transesophageal echocardiography demonstrates venous emboli (VE) after tourniquet deflation during intramedullary guided TKA. Extramedullary guides avoid manipulating the marrow cavity. We determined the incidence of VE in 20 patients undergoing extramedullary guided TKA. Recordings of hemodynamic variables, mixed venous oximetry, end-tidal CO2 and N2 tensions, and echocardiograph images occurred after induction of anesthesia, after tourniquet inflation, during cementing, and for 15 min after tourniquet deflation. Large VE appeared in 14 patients and small VE in the other 6 patients. Large VE occurred only after deflation of the tourniquet. Beginning 3 min after tourniquet deflation, mean pulmonary arterial pressures increased from the baseline of 21 +/- 1.0 to 30 +/- 1.3 mm Hg and remained increased for the duration of the procedure. The incidence of large VE with extramedullary guided TKA did not differ compared to the previously reported incidence with intramedullary guided TKA. These data suggest that VE might arise from a thrombogenic effect of the tourniquet rather than from manipulation of the marrow cavity.