The Twilight Zone as a Major Foraging Habitat and Mercury Source for the Great White Shark

The twilight zone contains the largest biomass of the world's ocean. Identifying its role in the trophic supply and contaminant exposure of marine megafauna constitutes a critical challenge in the context of global change. The white shark (Carcharodon carcharias) is a threatened species with some of the highest concentrations of neurotoxin methylmercury (MeHg) among marine top predators. Large white sharks migrate seasonally from coastal habitats, where they primarily forage on pinnipeds, to oceanic offshore habitats. Tagging studies suggest that while offshore, white sharks may forage at depth on mesopelagic species, yet no biochemical evidence exists. Here, we used mercury isotopic composition to assess the dietary origin of MeHg contamination in white sharks from the Northeast Pacific Ocean. We estimated that a minimum of 72% of the MeHg accumulated by white sharks originates from the consumption of mesopelagic prey, while a maximum of 25% derives from pinnipeds. In addition to highlighting the potential of mercury isotopes to decipher the complex ecological cycle of marine predators, our study provides evidence that the twilight zone constitutes a crucial foraging habitat for these large predators, which had been suspected for over a decade. Climate change is predicted to expand the production of mesopelagic MeHg and modify the mesopelagic biomass globally. Considering the pivotal role of the twilight zone is therefore essential to better predict both MeHg exposure and trophic supply to white sharks, and effectively protect these key vulnerable predators.

Skeletal muscle and cardiac transcriptomics of a regionally endothermic fish, the Pacific bluefin tuna, Thunnus orientalis

Background

The Pacific bluefin tuna (Thunnus orientalis) is a regionally endothermic fish that maintains temperatures in their swimming musculature, eyes, brain and viscera above that of the ambient water. Within their skeletal muscle, a thermal gradient exists, with deep muscles, close to the backbone, operating at elevated temperatures compared to superficial muscles near the skin. Their heart, by contrast, operates at ambient temperature, which in bluefin tunas can range widely. Cardiac function in tunas reduces in cold waters, yet the heart must continue to supply blood for metabolically demanding endothermic tissues. Physiological studies indicate Pacific bluefin tuna have an elevated cardiac capacity and increased cold-tolerance compared to warm-water tuna species, primarily enabled by increased capacity for sarcoplasmic reticulum calcium cycling within the cardiac muscles.

Results

Here, we compare tissue-specific gene-expression profiles of different cardiac and skeletal muscle tissues in Pacific bluefin tuna. There was little difference in the overall expression of calcium-cycling and cardiac contraction pathways between atrium and ventricle. However, expression of a key sarcoplasmic reticulum calcium-cycling gene, SERCA2b, which plays a key role maintaining intracellular calcium stores, was higher in atrium than ventricle. Expression of genes involved in aerobic metabolism and cardiac contraction were higher in the ventricle than atrium. The two morphologically distinct tissues that derive the ventricle, spongy and compact myocardium, had near-identical levels of gene expression. More genes had higher expression in the cool, superficial muscle than in the warm, deep muscle in both the aerobic red muscle (slow-twitch) and anaerobic white muscle (fast-twitch), suggesting thermal compensation.

Conclusions

We find evidence of widespread transcriptomic differences between the Pacific tuna ventricle and atrium, with potentially higher rates of calcium cycling in the atrium associated with the higher expression of SERCA2b compared to the ventricle. We find no evidence that genes associated with thermogenesis are upregulated in the deep, warm muscle compared to superficial, cool muscle. Heat generation may be enabled by by the high aerobic capacity of bluefin tuna red muscle.

Biomechanical Analysis of the Slow-Twitch (Red) Muscle Force Transmission Pathways in Tunas

In tunas, the slow-twitch red muscle, which has an elevated temperature, powers thunniform locomotion, a stiff-bodied swimming style. The anatomical placement and operating temperatures of red muscle vary widely among teleosts: in tunas, the red muscle is located centrally in the body, adjacent to the spine, and maintains an elevated temperature. In the majority of ectothermic teleosts, red muscle is located laterally in the body, adjacent to the skin, and operates at ambient temperature. The specialized physiology and biomechanics of red muscle in tunas are often considered important adaptations to their high-performance pelagic lifestyle; however, the mechanics of how muscular work is transmitted to the tail remains largely unknown. The red muscle has a highly pennate architecture and is connected to the spine through a network of bones (epicentral bones) and long tendons (posterior oblique tendons). The network of long tendons has been hypothesized to enhance the power transmitted to the tail. Here, we investigate the morphology and biomechanics of the tuna's red muscle and tendons to determine whether elasticity is exploited to reduce the cost of transport, as is the case in many terrestrial vertebrates. To address this question, we evaluate two hypotheses: (1) tendons stretch during red-muscle-actuated swimming and (2) tendons comprise the primary load transmission pathway from the red muscle to the spine. To evaluate these hypotheses, we measured the mechanical properties of the posterior oblique tendons and performed novel dissections to estimate the peak force that the red muscle can generate. The force-generating capacity of the red muscle is calculated to be much greater than the load-bearing capacity of the posterior oblique tendons. Thus, the long tendons likely stretch under force from the red muscle, but they are not strong enough to be the primary force transmission pathway. These results suggest that other pathways, such as serial load transmission through the red muscle myomeres to the great lateral tendon and/or the anterior oblique tendons to the skin, transmit appreciable force to the tail.

The importance of migratory connectivity for global ocean policy

The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.

Phylotranscriptomic Insights into the Diversification of Endothermic Thunnus Tunas

Birds, mammals, and certain fishes, including tunas, opahs and lamnid sharks, are endothermic, conserving internally generated, metabolic heat to maintain body or tissue temperatures above that of the environment. Bluefin tunas are commercially important fishes worldwide, and some populations are threatened. They are renowned for their endothermy, maintaining elevated temperatures of the oxidative locomotor muscle, viscera, brain and eyes, and occupying cold, productive high-latitude waters. Less cold-tolerant tunas, such as yellowfin tuna, by contrast, remain in warm-temperate to tropical waters year-round, reproducing more rapidly than most temperate bluefin tuna populations, providing resiliency in the face of large-scale industrial fisheries. Despite the importance of these traits to not only fisheries but also habitat utilization and responses to climate change, little is known of the genetic processes underlying the diversification of tunas. In collecting and analyzing sequence data across 29,556 genes, we found that parallel selection on standing genetic variation is associated with the evolution of endothermy in bluefin tunas. This includes two shared substitutions in genes encoding glycerol-3 phosphate dehydrogenase, an enzyme that contributes to thermogenesis in bumblebees and mammals, as well as four genes involved in the Krebs cycle, oxidative phosphorylation, β-oxidation, and superoxide removal. Using phylogenetic techniques, we further illustrate that the eight Thunnus species are genetically distinct, but found evidence of mitochondrial genome introgression across two species. Phylogeny-based metrics highlight conservation needs for some of these species.

Microarray gene expression profiles from mature gonad tissues of Atlantic bluefin tuna, Thunnus thynnus in the Gulf of Mexico

Background

Bluefin tunas are highly prized pelagic fish species representing a significant economic resource to fisheries throughout the world. Atlantic bluefin tuna (Thunnus thynnus) populations have significantly declined due to overexploitation. As a consequence of their value and population decline, T. thynnus has been the focus of considerable research effort concerning many aspects of their life history. However, in-depth understanding of T. thynnus reproductive biology is still lacking. Knowledge of reproductive physiology is a very important tool for determining effective fisheries and aquaculture management. Transcriptome techniques are proving powerful and provide novel insights into physiological processes. Construction of a microarray from T. thynnus ESTs sourced from reproductive tissues has provided an ideal platform to study the reproductive physiology of bluefin tunas. The aim of this investigation was to compare transcription profiles from the ovaries and testes of mature T. thynnus to establish sex specific variations underlying their reproductive physiology.

Results

Male and females T. thynnus gonad tissues were collected from the wild and histologically staged. Sub-samples of sexually mature tissues were also measured for their mRNA differential expression among the sexes using the custom microarray design BFT 4X44K. A total of 7068 ESTs were assessed for differential expression of which 1273 ESTs were significantly different (p<0.05) with >2 fold change in expression according to sex. Differential expression for 13 of these ESTs was validated with quantitative PCR. These include genes involved in egg envelope formation, hydration, and lipid transport/accumulation more highly expressed in ovaries compared with testis, while genes involved in meiosis, sperm motility and lipid metabolism were more highly expressed in testis compared with ovaries.

Conclusions

This investigation has furthered our knowledge of bluefin tunas reproductive biology by using a contemporary transcriptome approach. Gene expression profiles in T. thynnus sexually mature testes and ovaries were characterized with reference to gametogenesis and potential alternative functions. This report is the first application of microarray technology for bluefin tunas and demonstrates the efficacy by which this technique may be used for further characterization of specific biological aspects for this valuable teleost fish.

Surface plasmon polarization filtering in a single mode dielectric waveguide

We demonstrate that metallic electrodes symmetrically placed about a single mode dielectric waveguide can effectively polarize the mode by excitation of surface plasmons. The transmission through the metal electrode waveguide structure is examined as a function of mode polarization and electrode spacing. It is found that modes polarized perpendicular to the metal surface can resonantly excite surface plasmons, extinguishing the mode in the waveguide core, while modes polarized parallel to metal surface only suffer mode attenuation due to the presence of the metal. The phase matching conditions for excitation of surface plasmons are examined and the polarization and insertion loss of the transmitted mode is experimentally verified.

Comparative effects of oral esterified estrogens with and without methyltestosterone on endocrine profiles and dimensions of sexual function in postmenopausal women with hypoactive sexual desire

OBJECTIVE

In some women, a decline in sexual interest accompanies a relative androgen insufficiency after menopause. We sought to characterize the hormonal effects of the combination of oral esterified estrogens and methyltestosterone and to investigate whether this regimen improves hypoactive sexual desire.

DESIGN

Double-blind randomized trial.

SETTING

Healthy volunteers in a multicenter research environment.

PATIENT(S)

Postmenopausal women taking estrogen therapy who were experiencing hypoactive sexual desire.

INTERVENTION(S)

4 months of treatment with 0.625 mg of esterified estrogens (n = 111) or the combination of 0.625 mg of esterified estrogens and 1.25 mg of methyltestosterone (n = 107).

MAIN OUTCOME MEASURES

Baseline and end-of-study measurements of total and bioavailable testosterone and sex hormone-binding globulin (SHBG), and mean change in level of sexual interest or desire as rated on the Sexual Interest Questionnaire.

RESULT(S)

Treatment with the combination of esterified estrogens and methyltestosterone significantly increased the concentration of bioavailable testosterone and suppressed SHBG. Scores measuring sexual interest or desire and frequency of desire increased from baseline with combination treatment and were significantly greater than those achieved with esterified estrogens alone. Treatment with the combination was well tolerated.

CONCLUSION(S)

Increased circulating levels of unbound testosterone and suppression of SHBG provide a plausible hormonal explanation for the significantly improved sexual functioning in women receiving the combination of esterified estrogen and methyltestosterone.

The dance: essence of embodiment

An analysis of movement, and particularly of dance, helps us to see in an extraordinarily effective way the meaning of embodiment. This paper then looks through the eyes of dance theorists and at philosophers who consider dance and movement and their meaning of embodiment. A study of movement and dance encompasses the fullest meaning of embodiment: that the embodied way of being-in-the-world is also an embedded way of being in a world of others. Dance has critically important social ramifications. In our own and other cultures, dance plays an important role in healing and in health enhancement.

Toronto street youth and HIV/AIDS: prevalence, demographics, and risks

PURPOSE

The purposes of this study were: (a) to identify human immunodeficiency virus (HIV) prevalence in Toronto street youth through paired blood and saliva specimens; (b) to identify the HIV risk and prevention behaviors of street involved youth; and (c) to identify demographic or other factors that may contribute to the risk of street youth becoming infected with HIV/acquired immunodeficiency syndrome (AIDS) in the future.

METHODS

This was a cross-sectional convenience study of street-involved youth aged 14-25 years. The youth participated in interviews to identify HIV-related knowledge and personal risk and preventive behaviors. Following interviews, they were asked to provide a saliva sample, blood spot, or both. They could refuse one or both samples without jeopardizing their involvement or receiving an honorarium. Two males were the only participants who declined to provide a sample.

RESULTS

Fifteen of 695 (2.2%) youth tested positive for HIV infection. All were male, ranging in age from 18 to 25 years. Same and opposite sex, intravenous (IV) drug use, prostitution, and incarceration were risk factors associated with positive HIV test results. The rate of HIV infection was seven times greater for the group 20 years of age and older (20-25) compared to the younger group aged 14-9 years. The proportion testing positive for HIV from small cities, towns, and rural communities in Ontario was 40%; yet, they represented 21% of the study population. Most (57%) youth had been on their own for no more than 3 years and had moved frequently. Nearly two thirds (60%) had stayed in hostels or homeless shelters in the previous 6 months.

CONCLUSION

Street youth in Canada are at high risk of HIV infection with their risk increasing with age. Unprotected (same and opposite) sex, IV drug use, prostitution and incarceration were linked to their HIV infections. The high level of mobility identified by street youth challenges governments, communities, and public health officials to develop appropriate prevention strategies and to carefully monitor the spread of HIV infection in this vulnerable population.

Efforts to improve the follow-up of patients with abnormal Papanicolaou test results

BACKGROUND

We describe and evaluate efforts to improve the follow-up care of patients with abnormal Papanicolaou test results at an academic family practice center at Shadyside Hospital in Pittsburgh.

METHODS

From 1994 to 1996, 1796 patients received Papanicolaou testing; 147 (8 percent) of the smears had abnormal findings--16 percent had atypia, 83 percent had dysplasia, and 1 percent had carcinoma in situ. Patients received follow-up care based on a formalized protocol using educational input, logistic aids, and automated prompting.

RESULTS

Overall follow-up success rates and colposcopy completion rates increased dramatically. Whereas 36 percent of patients with abnormal findings on Papanicolaou smears had been overdue for follow-up in 1990, only 13 percent were overdue in 1996 after our interventions. Patients assigned to Papanicolaou testing for follow-up of abnormal findings failed to receive a test in 9 of 45 (20 percent) cases, but those assigned to colposcopy follow-up failed to receive a test in only 10 of 102 (10 percent) of cases. Appointment failure rates at colposcopy clinic dropped from 56 percent in 1993 to 12 percent in 1996. Colposcopic biopsy was far superior to Papanicolaou test for detecting precursors of cervical cancer at follow-up.

CONCLUSIONS

Educational programs, formalized approaches to care, transportation assistance, and reminder systems are not only practical but also can dramatically improve the outcome of cervical cancer screening programs.

Difficulties in evaluating abnormal lead screening results in children

BACKGROUND

This report chronicles efforts to provide follow-up care for children with abnormal whole blood lead concentrations using the 1991 Centers for Disease Control and Prevention (CDC) guidelines in the Family Health Center at Shadyside Hospital in Pittsburgh.

METHODS

An automated surveillance module found all children with abnormal lead concentrations obtained between January 1994 and July 1995 and singled out children who were overdue for follow-up. Automated physician reminders and nursing case management were used to improve care and documentation. Longitudinal case summaries were used to evaluate care.

RESULTS

All 99 children with a lead concentration of 10 micrograms/dL or greater had a documented follow-up plan. Twenty-nine children (47 percent) who had a lead concentration of 10 to 14 micrograms/dL, 23 (100 percent) who had a lead concentration of 15 to 19 micrograms/dL, and 8 (100 percent) who had a lead concentration of 20 micrograms/dL or greater had at least one follow-up lead concentration measurement by the end of the data collection in July 1995. Follow-up was incomplete in more than 70 percent of children. Nineteen children (19 percent) with initially abnormal lead concentrations had follow-up testing with persistently normal results. The yearly cost of follow-up was $15,888, with only 7 children requiring county health environmental intervention.

CONCLUSIONS

The nurse-centered, computer-aided system improved follow-up care of children with abnormal lead concentrations, but most patients still did not receive mandated follow-up testing because of logistic obstacles. The effort and cost associated with CDC-mandated follow-up of children with lead concentrations between 10 and 19 micrograms/dL provides no apparent benefit and might detract from the care of children at higher risk.

Influence of family functioning and income on vaccination in inner-city health centers

OBJECTIVES

To assess family functioning and consumer decision-making about vaccinations and to compare the results with age at vaccination.

DESIGN

Self-administered survey that was mailed to parents with comparison to vaccination records from chart audits.

SETTINGS

Two inner-city health centers in Pittsburgh, Pa, that receive free vaccine supplies.

PARTICIPANTS

Systematic sample from the billing computer records of parents whose children were aged 2 to 4 years as of July 2, 1993.

INTERVENTIONS

The survey used simplified versions of the Family Profile and the Triandis model of consumer decision-making that includes perceived consequences of vaccinations, attitude about vaccinations, social influences, and facilitating conditions (eg, ease of obtaining an appointment).

MAIN OUTCOME MEASURES

Variables associated with age at vaccination for third diphtheria and tetanus toxoids and pertussis vaccine immunization and first measles-mumps-rubella immunization.

RESULTS

Of 395 families, 167 responded. Higher family dysfunction scores and lower family concordance scores each were associated with receiving first measles-mumps-rubella vaccination (P < or = .02) and third diphtheria and tetanus toxoids and pertussis vaccination (P < = .02) at later ages. Many (30%-54%) of the respondents reported that they knew little about the risks and benefits of vaccination. However, knowledge about vaccines was not associated with vaccination status. Those respondents with an annual income of less than $10000 received the first measles-mumps-rubella vaccination later than those with an annual income $10000 or greater (P < .02) when the data were analyzed by age at vaccination but not when the data were analyzed as on-time vs late vaccinations.

CONCLUSIONS

To increase vaccination rates in innercity clinics, strategies need to consider family dysfunction and income and not merely focus on education. The use of age at vaccination as a continuous variable offers advantages over the dichotomy of immunized vs not immunized.

Development of a portable information system: connecting palmtop computers with medical records systems and clinical reference resources

The portability of palmtop computers makes them an ideal platform to maintain communication between busy physicians and medical information systems. In our academic FHC (Family Health Center) we have developed software that runs on a palmtop computer allowing access to information in the HIS (Hospital Information System) and our FHC's AAMRS (Automated Ambulatory Medical Record System). The resident physicians who staff the hospital and the FHC are frequently at home or otherwise off-site where terminal access is not available. Using a Hewlett-Packard 95LX palmtop computer as the base platform, custom software has been developed to access summary data on in-patients and out-patients. Data is downloaded into a database on a palmtop computer memory card. ASCII data from Medical Information Systems (MIS), is transformed into a database format readable on the palmtop. Our hospital MIS department transmits information daily on our in-patient service (20-30 patients). We also download, weekly, a patient summary on all of our active out-patients in our MUMPS-based AAMRS (2500-3000 patients). Each morning the resident in the Family Practice program updates his palmtop memory card at a central workstation. Palmtop computers with downloaded databases, can be valuable in care of patients when the physical or on-line chart is not easily accessible. They are particularly useful in multi-physician groups when the on-call physician provides care for the patients of other physicians. We have made the palmtop computer even more valuable to physicians by providing an integrated software package.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis and management of the paranoid patient

Patients with symptoms of paranoia often present to primary care physicians. The paranoia may range in severity from a mild and largely incidental finding to a psychotic symptom. In its more severe forms, paranoia may constitute the chief complaint or may interfere with the patient's ability to accept treatment for other medical conditions. After an assessment of the severity of the symptoms and consideration of an organic etiology, initial treatment is often begun with a supportive approach and the prescription of a neuroleptic medication.

Signing out patients for off-hours coverage: comparison of manual and computer-aided methods

This paper evaluates the communication of information to physicians who provide off-hours coverage to inpatients in two Family Practice residency programs.

METHOD

To describe the importance and accessibility of clinical information used by on-call residents in covering hospital patients, we administered a questionnaire. Then following the use of a new computerized sign-out system in one of the programs, residents filled out the same questionnaire again.

RESULTS

Residents felt that a "to do" list and information about the patient's "code status" were the most important data desired from sign-out sheets. However, 69% of residents in both programs felt that provision of this information was normally poor. Nearly all of the residents in Buffalo, using an entirely handwritten sign-out sheet, felt it was in need of improvement. Residents in Pittsburgh, using a summary aided by the hospital's computer print-out, felt this need much less acutely. After implementation of a new computerized sign-out sheet in Buffalo, residents indicated a slightly higher level of satisfaction. The work of data entry and re-entry into the computer was unpopular and inefficient.

CONCLUSION

The present method of transferring information at the end of a work day is not satisfactory for residents. Provision of data summaries from existing hospital information systems is a good first step in improving data transfer. A further study of more comprehensive automated sign-out systems is important, because of the increasing discontinuity of house officer care.

The interferon-induced Mx-homologous protein in people with symptomatic HIV-1 infection

Twenty-six people with symptomatic HIV-1 infection were screened for the presence of interferon (IFN) alpha and IFN alpha antibodies in their sera and the presence of the IFN-induced intracellular Mx-homologous protein in their peripheral blood leukocytes. Eleven people had measurable IFN alpha levels ranging from 1 to 40 IU/ml. None of the sera tested was positive for IFN alpha binding or IFN alpha neutralizing antibodies in the assays employed. Twenty-five of the 26 people had significant levels of the Mx-homologous protein in their peripheral mononuclear cells. The Mx concentrations varied from 0.3 to 6 U/ml in the people studied. IFN alpha-positive people had significantly higher levels of the Mx homolog than IFN alpha-negative people (P less than 0.03). Furthermore, the Mx homolog content in Walter-Reed class 2 people was significantly lower than in Walter-Reed class 5/6 people (P less than 0.01). Our results suggest that the IFN system is activated in more than 90% of the people with lymphadenopathy-associated syndrome, AIDS-related complex and AIDS. Since acid-labile IFN alpha can induce the Mx homolog in vitro endogenously produced IFN alpha seems likely to be responsible for the high Mx homolog levels detected.

Automated health surveillance

A successful health maintenance program requires physicians interested in and knowledgeable about the appropriate health surveillance actions to pursue. But even well-informed physicians need help transforming good intentions into effective health surveillance. An automated health surveillance system was designed and implemented to simplify documentation of health maintenance and remind physicians when actions are overdue. The system has increased insight into the complex process of health promotion and promises to be an important clinical, educational, and research tool.

Intralesional interferon-alpha therapy in advanced malignant melanoma

Fifty-one evaluable patients with histologically proven metastatic melanoma and at least one skin metastasis were treated intralesionally with interferon-alpha (IFN-alpha). Twenty-six of the patients were given highly purified natural IFN-alpha 6 Mio. IU three times per week. Twenty-five patients were given 10 Mio. IU three times per week of a recombinant IFN-alpha 2b (rIFN-alpha 2b). All patients were examined for systemic and local responses to this treatment. The systemic responses consisted of nine objective remissions, each of which lasted from 2 to 18 or more months. There were 24 complete or partial local responses. Forty-two of the 51 patients had at least two skin metastases so that IFN-injected and noninjected tumor sites could be compared. The difference between systemic and local efficacy was highly significant statistically (P = 0.0004). The results show that IFN-alpha has clinically observable antitumor activity in malignant melanoma.

Biochemical and ultrastructural characterization of the 1,4-dihydropyridine receptor from rabbit skeletal muscle. Evidence for a 52,000 Da subunit

The 1,4-dihydropyridine receptor purified from rabbit skeletal muscle contains four polypeptide components of 175,000 Da (nonreduced)/150,000 Da (reduced), 170,000, 52,000, and 32,000 Da (Leung, A. T., Imagawa, T., and Campbell, K. P. (1987) J. Biol. Chem. 262, 7943-7946). A monoclonal antibody specific to the 52,000-Da polypeptide component of the dihydropyridine receptor has been produced and used in immunoprecipitation and immunoblotting experiments to demonstrate that the 52,000-Da polypeptide is an integral subunit of the purified dihydropyridine receptor. Peptide mapping experiments with 32P-labeled dihydropyridine receptor have also demonstrated that the 52,000-Da polypeptide is distinct from and not a proteolytic fragment of the 170,000-Da subunit. Densitometric scanning of Coomassie Blue-stained sodium dodecyl sulfate-polyacrylamide gels of the purified dihydropyridine receptor has demonstrated that the 52,000-Da polypeptide exists in a 1:1 stoichiometric ratio with the 170,000-, 175,000/150,000-, and 32,000-Da subunits of the dihydropyridine receptor. Electron microscopy of the freeze-dried, rotary-shadowed dihydropyridine receptor has shown that the preparation contains a homogeneous population of 16 x 22-nm ovoidal particles large enough to contain all four polypeptides of the dihydropyridine receptor. The particles have two distinct components of similar size which may represent the location in the molecule of the two larger subunits.

[Low-dose alpha-interferon treatment of hairy cell leukemia]

Fifteen patients (36-71 years old) with histologically proven hairy-cell leukemia were treated with a low dose of IFN-alpha. The treatment consisted of 1 million I.U. given daily subcutaneously. After 1 month the dose was reduced in all patients 1 million I.U. thrice weekly. Four of the 15 patients have been splenectomized, with two patients receiving chemotherapy prior to the IFN treatment. All patients exhibited at least one cytopenia. The IFN treatment was well tolerated. Only two of the 15 patients experienced mild fever after the first injection, one patient had apathia and mild somnolence after 2 months of therapy. At present 15 patients can be evaluated: 6-18 months after start of therapy two patients showed a complete response with normalization of both peripheral blood and bone marrow, 10 patients experienced a partial response, while one patient showed a slight response with improvement of the thrombocyte count only. Two patients showed no improvement after 3 months of therapy; these patients are presently being treated with 5 million I.U. IFN-alpha thrice weekly. In spite of the low number of patients these data strongly indicate that IFN-alpha-2 is effective in hairy-cell leukemia at this low dose.

The lithium loading dose method in a clinical setting

The lithium loading dose method developed by Cooper and associates resulted in achievement of therapeutic concentrations in 29 of 30 psychiatric inpatients. Fewer lithium determinations were required than in 30 other inpatients treated with the traditional trial-and-error technique.

Cerebral angiitis and intracerebral hemorrhage associated with methamphetamine abuse. Case report

✓ A case of reversible cerebral angiitis and intracerebral hemorrhage is reported in a methamphetamine abuser. Characteristic radiographic changes were demonstrated by selective cerebral angiography and computerized tomography. These vascular abnormalities disappeared after 1 month of treatment with prednisone, during which time the patient denied further drug abuse.

Dowel pin positioning technique for fixed partial denture working casts

This simple, accurate technique of positioning dowel pins saves the time and effort of working with cumbersome bobby pins, paper clips, anesthetic needles, and sticky wax. No pins are pushed into the impression material that might cause distortion. The method (1) allows the dental laboratory technician to place the dowel pins free hand after the impression has been poured and (2) does away with many problems associated with prepositioning the dowel and stabilizing it with sticky wax before pouring the impression. With this method, there is nothing to vibrate loose, and there is excellent vision and access for teasing stone into all recesses of the impression with a spatula or brush. The heavy body and sticky characteristic of Mortite ensures that the bankers pins will not be dislodged during vibration of stone, and the dowel pins can be precisely located.

The development of a pediatric emergency transport system

This article discusses the role of the pediatric emergency transport system as an outreach modality of the pediatric intensive care unit. Most of the discussion focuses on the Denver model.

The use of synthetic luteinizing hormone-releasing hormone to induce ovulation

The therapeutic use of synthetic luteinizing hormone-releasing hormone (LH-RH) to induce ovulation has been explored. Three dosage schemes have been compared: a single dose of LH-RH, multiple doses of LH-RH, and LH-RH used in combination with human menopausal gonadotrophins (HMG). The results of these three schemes are presented and compared; the last regimen has proved most successful, with a high pregnancy rate, a low incidence of multiple pregnancy and no evidence of ovarian hyperstimulation.

Preparing students for physical restraint

While not encouraging the use of physical restrains on mental patients, the author presents a statement of its continuing use and underscores the need for preparing students for a group of traditional procedures that in some ways are increasingly out of step with our times and aesthetically offensive. Two specific clinical indications for restraint are discussed.

Ego-supportive care in open-heart surgery

Open heart surgery has been shown to have a rate of occurrence of postoperative psychopathological phenomena (9 percent-57 percent) many times greater than that of general surgery (1/1500). These phenomena result from an interplay of organic, environmental, psychological, and social factors which act on the integrative and coping capacity of the ego.

Treatment is accomplished through support of the ego by: 1) establishment of a relationship, 2) reassurance, 3) environmental support, 4) consultative relationships with staff, 5) ventilation of feelings, 6) medical measures in support of somatic function, and 7) anti-anxiety drugs. Such supportive measures are usually effective in bringing about a rapid remission of these psychopathological phenomena.