Plasma and acrosomal membrane lipid content of saltwater crocodile spermatozoa

This study describes the chemical lipid composition of the sperm plasma and acrosomal membranes of the saltwater crocodile Crocodylus porosus with the aim of providing new insights into sperm physiology, particularly that associated with their preservation ex vivo . The specific fatty acid composition of the sperm plasma and acrosomal membranes is documented. The mean (±s.d.) ratio of unsaturated to saturated membrane fatty acids within the plasma membrane was 2.57±0.50, and was determined to be higher than a similar analysis of the lipids found in the acrosomal membrane (0.70±0.10). The saltwater crocodile sperm plasma membrane also contained remarkably high levels of cholesterol (mean (±s.d.) 40.7±4.5 nmol per 106 sperm cells) compared with the spermatozoa of other amniote species that have so far been documented. We suggest that this high cholesterol content could be conferring stability to the crocodile sperm membrane, allowing it to tolerate extreme osmotic fluxes and rapid changes in temperature. Our descriptive analysis now provides those interested in reptile and comparative sperm physiology an improved baseline database for interpreting biochemical changes associated with preservation pathology (e.g. cold shock and cryoinjury), epididymal sperm maturation and capacitation/acrosome reaction.

Cross-hemispheric functional connectivity in the human fetal brain

Compelling evidence indicates that psychiatric and developmental disorders are generally caused by disruptions in the functional connectivity (FC) of brain networks. Events occurring during development, and in particular during fetal life, have been implicated in the genesis of such disorders. However, the developmental timetable for the emergence of neural FC during human fetal life is unknown. We present the results of resting-state functional magnetic resonance imaging performed in 25 healthy human fetuses in the second and third trimesters of pregnancy (24 to 38 weeks of gestation). We report the presence of bilateral fetal brain FC and regional and age-related variation in FC. Significant bilateral connectivity was evident in half of the 42 areas tested, and the strength of FC between homologous cortical brain regions increased with advancing gestational age. We also observed medial to lateral gradients in fetal functional brain connectivity. These findings improve understanding of human fetal central nervous system development and provide a basis for examining the role of insults during fetal life in the subsequent development of disorders in neural FC.

Dietary patterns, insulin sensitivity and inflammation in older adults

Background/Objectives

Several studies have linked dietary patterns to insulin sensitivity and systemic inflammation, which affect risk of multiple chronic diseases. The purpose of this study was to investigate the dietary patterns of a cohort of older adults, and examine relationships of dietary patterns with markers of insulin sensitivity and systemic inflammation.

Subjects/Methods

The Health, Aging and Body Composition (Health ABC) Study is a prospective cohort study of 3075 older adults. In Health ABC, multiple indicators of glucose metabolism and systemic inflammation were assessed. Food intake was estimated with a modified Block food frequency questionnaire (FFQ). In this study, dietary patterns of 1751 participants with complete data were derived by cluster analysis.

Results

Six clusters were identified, including a ‘Healthy foods’ cluster, characterized by higher intake of lowfat dairy products, fruit, whole grains, poultry, fish and vegetables. In the main analysis, the ‘Healthy foods’ cluster had significantly lower fasting insulin and HOMA-IR than the ‘Breakfast cereal’ and ‘High-fat dairy products’ clusters, and lower fasting glucose than the ‘High-fat dairy products’ cluster (P ≤ 0.05). No differences were found in 2-hour glucose. With respect to inflammation, the ‘Healthy foods’ cluster had lower IL-6 than the ‘Sweets and desserts’ and ‘High-fat dairy products’ clusters, and no differences were seen in CRP or TNF-α.

Conclusions

A dietary pattern high in lowfat dairy products, fruit, whole grains, poultry, fish and vegetables may be associated with greater insulin sensitivity and lower systemic inflammation in older adults.

Successful management of recurrent coccygeal hernia with the de-epithelialised rectus abdominis musculocutaneous flap

OBJECTIVE

Little data exist about the optimal management of the rare coccygeal hernia. A novel method of repair is reported.

METHODS

A 46-year-old woman presented with a symptomatic coccygeal hernia after resection of the coccyx for a tumour. She had previously been reconstructed with an on-lay polytetrafluorethylene (PTFE) mesh but subsequently developed a hernia. A de-epithelialised vertical rectus abdominis musculocutaneous flap was elevated and passed through the hernia defect. The de-epithelialised dermis was secured to the levator ani and to the periosteum of the sacrum via access through a posterior approach. The gluteal skin was closed primarily over the inset flap.

RESULTS

The de-epithelialised rectus abdominis musculocutaneous flap is a viable option for the treatment of coccygeal hernia.

RELEVANCE

The de-epithelialised rectus abdominis flap has several advantages over other techniques including mesh repair and anterior or posterior flap repairs of the coccygeal hernia. The transposed muscle blocks herniation through the pelvic floor and does not create the dead space that is associated with posterior flap repairs such as the bilateral gluteal advancements. It also has the advantages of the posterior approach mesh repair, as the de-epithelialised dermis provides significant strength when secured like mesh to healthy local tissue.

Hepatitis B virus transcription and replication

Hepatitis B virus (HBV) replicates by the reverse transcription of the 3.5-kb viral pregenomic RNA. Therefore, the regulation of the transcription of the pregenomic RNA is a critical step in the viral life cycle. Various ubiquitous and liver-enriched transcription factors have been shown to modulate the level of RNA synthesis from the core promoter. The nuclear hormone receptors HNF4 and RXRalpha plus PPARalpha appear to have a critical role in governing pregenomic RNA synthesis from the core promoter in cell culture and probably represent a major determinant governing the hepatotropism of this virus. The level of 3.5-kb HBV RNA synthesis is approximately proportional to the level of viral replication in cell culture; however, this is not the case in the liver of HBV transgenic mice. Directly modulating the levels or activities of specific transcription factors known to regulate HBV transcription in cell culture can increase viral replication in HBV transgenic mice without greatly changing the levels of HBV transcripts. Various immune stimuli that alter transcription factor activities involved in regulating viral RNA synthesis can negatively affect viral replication without affecting HBV transcription. These observations suggest that in vivo very subtle changes in HBV transcription may contribute to large alterations, either negative or positive, in viral replication. Investigation of transcription factor-null HBV transgenic mice under various physiological conditions will be required to establish the putative role of specific transcription factors in regulating viral replication in vivo.

Trials and tribulations in deploying digital imaging network and picture archiving and communication system--film to filmless in 80 days

The Naval Medical Center Portsmouth (NMCP) was constructed with the intention of deploying a picture archiving and communications system (PACS). All necessary infrastructures were installed and considerable planning was done during construction with the belief that this would make the deployment of the PACS much simpler. This was true during the early deployment; however, as time passed and the system was more heavily used, significant problems arose. User/operator-related and hardware/software-related problems were encountered. Although, most have been corrected, some have persisted and will require considerable manpower and/or fiscal resources to correct. The lesson learned is that no matter how much preparation is done for deploying PACS, many significant problems will surface as the system is used that will require the continued attention of the deployment project officer.

An improved method for conjugating monoclonal antibodies with N-hydroxysulfosuccinimidyl DOTA

A simple, water-soluble procedure for conjugation of monoclonal antibodies to 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) has been improved by optimizing pH, buffer, and temperature conditions for the preparation of N-hydroxysulfosuccinimidyl DOTA and its conjugation to the human/murine chimeric anti-carcinoembryonic antigen antibody cT84.66. This improved method results in a 6-fold increase in conjugation efficiency, a 3-7-fold decrease in antibody cross-linking, a more homogeneous population of conjugate species, and a 5-fold decrease in the quantities of reagents needed for conjugation. The cT84.66-DOTA conjugate was labeled to high specific activity with 111In, 90Y, 88Y, 64Cu, and 67Cu, affording near-quantitative incorporation of the majority of these radiometals. This improved conjugation procedure facilitates large-scale production and radiometal labeling of cT84.66-DOTA for clinical radioimmunotherapy trials.

Metabolism and renal clearance of 111In-labeled DOTA-conjugated antibody fragments

Radiometal-labeled antibody fragments are promising reagents for radioimmunotherapy due to their high tumor uptake and rapid pharmacokinetics, but their therapeutic potentials are limited by high uptake and retention in the kidney. Identification of metabolic products is a first step in designing rationale approaches to lower kidney uptake. Previous studies in rats have shown that 111In-labeled DTPA-conjugated antibody fragments (via lysine residues) were degraded to an DTPA-epsilon-amino-lysine derivative and retained in the lysosomal compartments of the liver and kidney [Rogers et al. (1995) Cancer Res. 55, 5714s-5720s]. To determine the metabolic profile of another widely used metal-chelate, [111In]DOTA conjugated to lysines in antibody fragments via active ester chemistry, we analyzed kidney homogenates from nude mice injected with an [111In]DOTA-Fab generated enzymatically from the anti-lymphoma intact antibody Rituxan. The major kidney metabolite was identified as [111In]DOTA-epsilon-amino-lysine by comparison to an authentic synthetic standard. This end product was also identified in the urine, along with relatively small amounts of [111In]DOTA-Fab. Since injection of [111In]DOTA-epsilon-amino-lysine into nude mice resulted in rapid clearance into the urine without kidney retention, it is likely that the renal retention observed was due to kidney uptake of [111In]DOTA-Fab, followed by lysosomal degradation to [111In]DOTA-epsilon-amino-lysine, which is only slowly cleared from this compartment. This observation is supported by autoradiographs of the kidney showing rapid localization of radioactivity into the distal regions of the kidney cortex. To extend this analysis to clinical trials, we have also analyzed urine taken from a patient injected with the intact antibody [111In]DOTA-cT84.66. In that example, we found that the major radioactive species was also [111In]DOTA-epsilon-amino-lysine.

High-resolution microPET imaging of carcinoembryonic antigen-positive xenografts by using a copper-64-labeled engineered antibody fragment

Rapid imaging by antitumor antibodies has been limited by the prolonged targeting kinetics and clearance of labeled whole antibodies. Genetically engineered fragments with rapid access and high retention in tumor tissue combined with rapid blood clearance are suitable for labeling with short-lived radionuclides, including positron-emitting isotopes for positron-emission tomography (PET). An engineered fragment was developed from the high-affinity anticarcinoembryonic antigen (CEA) monoclonal antibody T84.66. This single-chain variable fragment (Fv)-C(H)3, or minibody, was produced as a bivalent 80 kDa dimer. The macrocyclic chelating agent 1,4,7, 10-tetraazacyclododecane-N,N',N", N"'-tetraacetic acid (DOTA) was conjugated to the anti-CEA minibody for labeling with copper-64, a positron-emitting radionuclide (t(1/2) = 12.7 h). In vivo distribution was evaluated in athymic mice bearing paired LS174T human colon carcinoma (CEA positive) and C6 rat glioma (CEA negative) xenografts. Five hours after injection with (64)Cu-DOTA-minibody, microPET imaging showed high uptake in CEA-positive tumor (17.9% injected dose per gram +/- 3.79) compared with control tumor (6.0% injected dose per gram +/- 1.0). In addition, significant uptake was seen in liver, with low uptake in other tissues. Average target/background ratios relative to neighboring tissue were 3-4:1. Engineered antibody fragments labeled with positron-emitting isotopes such as copper-64 provide a new class of agents for PET imaging of tumors.

An apparatus for membrane-confined analytical electrophoresis

A membrane-confined analytical electrophoresis apparatus for measuring the solution charge of macromolecules has been described previously (T. M. Laue et al., Anal. Biochem. 1989, 182, 377-382). Presented here is a design for this apparatus, which permits the on-line acquisition and display of absorbance data from up to 512 positions along an analysis chamber. Concentration distributions of macromolecules in solution can be monitored in the chamber to provide steady-state electrophoresis, electrophoretic mobility and diffusion measurements. Buffer chambers press semipermeable membranes against the open ends of a fused-silica cuvette to form the analysis chamber. This configuration permits both the flow of buffer and the establishment of an electric field across the cuvette, while retaining macromolecules in the field of view. Though a gel may be included in the analysis chamber, none is required for gradient stabilization. The volume of sample required for analysis is 8 microL, most of which is recoverable. Experimental conditions can be varied during study by simply changing the circulating buffer and/or the electric field. The analysis and buffer chambers are held in an aluminum housing that sits in an aluminum water jacket. The water jacket provides temperature control, shielding from external electrical noise and also serves as an optical mask. Plans for the cell assembly, optical system and the computer interface for data acquisition are provided. The assembly and operation of the apparatus and the analysis of data are described.

Nurse practitioners, certified nurse midwives, and physician assistants in California

California's health care industry includes workers prepared in many ways to perform many jobs. One significant group of health care workers prepared to provide care that often overlaps with physician-generated services is known as "nonphysician providers." Commonly, this label refers to nurse practitioners (NPs), certified nurse midwives (CNMs), and physician assistants (PAs). In this article, we will describe this group in five main areas: (1) the characteristics of the current and projected workforce and programs preparing these professionals; (2) the current skill expectations and knowledge bases of each; (3) trends in the education of these health professionals; (4) innovative models of education of these health professionals; and (5) the inclusion of NPs, PAs, and CNMs in workforce planning in a changing health care system. We conclude that, particularly in light of the overlapping functions of this provider group with many physician functions, the NP, CNM, and NP workforces must be recognized and considered when planning for the future of the physician workforce.

Practice environment for nurse practitioners in California. Identifying barriers

Barriers exist that prevent nurse practitioners from using their primary health care knowledge and skills. We present the incidence of and specific barriers experienced by nurse practitioner respondents in California, the state with the largest number of nurse practitioners in the nation. A January 1995 survey was sent to all nurse practitioners certified in California to elicit their experiences regarding legal or social barriers in their practice, with space for an open-ended response. Of an estimated 3,895 nurse practitioners in California, 2,741 (70%) returned surveys. Most nurse practitioner (65%) respondents in California are providing primary care. Perceived barriers to practice are lack of prescriptive authority, lack of support from physicians, reimbursement difficulties, and lack of public awareness. Current barriers to nurse practitioner practice in California are similar to national barriers discovered in 1992 data. The development of interprofessional dialogue and the recognition of the contributions of all primary care professionals are some of the steps that can be taken to reduce these barriers and increase the use and effectiveness of nurse practitioners in primary care.

Runner with gout and an aortic valve nodule

A 33-yr-old male ran 10 miles, drank some beer, and developed pain in his left knee and ankle. He took some leftover antibiotics but was no better after 6 d, when a heart murmur and an aortic valve nodule were discovered. He was presumed to have endocarditis with septic arthritis and was started on intravenous antibiotics. On the second hospital day, synovial fluid analysis revealed acute gout, and the patient improved very rapidly on anti-gout therapy. The valvular nodule remained unexplained, but one very rare cause of valvular heart nodules is visceral gout. An unsuccessful attempt to resorb the nodule was made by using allopurinol. This patient demonstrates several points about gout in endurance athletes: 1) acute gout can mimic infectious endocarditis, 2) misdiagnosed or undertreated gout often leads to multiple joint involvement and sometimes to visceral tophi, and 3) athletes who exercise in warm weather and quench their thirst with cold beer are at risk for acute gout.

Calibration of a 241Am wound-monitoring system using Monte Carlo techniques

Monte Carlo techniques have been used to establish calibration factors and to predict gamma spectra for well-defined measurements. These techniques are routinely used to predict shielding requirements and critical specifications. The Lawrence Livermore National Laboratory is researching the feasibility of using Monte Carlo techniques to establish calibration factors for in vivo measurement systems. A pilot study was conducted to demonstrate the use of the Monte Carlo technique to calibrate in vivo measurement systems, to predict the efficiency of a wound measurement system and compare the predicted efficiency with the measured efficiency, and to investigate the effects of the source geometry and the detector size on the measured efficiency. Results of this study demonstrate good agreement between the Monte-Carlo-predicted efficiency and the measured efficiency for a wound calibration phantom. The effects of the source geometry and the detector size tend to conform to the physical processes that govern the measurement process. These results demonstrate that the Monte Carlo technique accurately predicts the in vivo measurement efficiency if the characteristics of the attenuating material and the Monte Carlo source geometry are properly established.

Radioimmunodetection of Hodgkin's disease and non-Hodgkin's lymphomas with monoclonal antibody to eosinophil peroxidase

The purpose of this study was to determine if a radiolabeled murine monoclonal antibody (EOS) directed against eosinophil peroxidase would localize specifically to tumor sites in patients with lymphomas infiltrated by eosinophils. Ten patients with Hodgkin's disease and eosinophilia, three patients with non-Hodgkin's lymphomas and eosinophilia and five control patients received an intravenous injection of 3-10 mg of EOS antibody radiolabeled with 74-155 MBq (2.0-4.2 mCi) of 111In. At intervals of 24, 48 and 72 hr after injection, gamma camera images were obtained along with blood and urine specimens and the imaging results were correlated with the results of other staging modalities. As early as 24 hr after antibody injection, there was clear visualization of identifiable sites of lymphoma with eosinophilia greater than 1 cm in size, including the spleen, bone marrow and lymph nodes. Although EOS also localized nonspecifically to the liver and, in some patients, to the nasopharynx, there was no appreciable uptake in normal bone marrow, spleen, uninvolved lymph nodes, lymphomas without eosinophilia or various other pathologic conditions without eosinophilia. Except for transient pain at tumor sites in three patients, no adverse reactions were noted. We conclude that a radiolabeled monoclonal antibody directed against eosinophil peroxidase localizes to lymphoma sites infiltrated by eosinophils.

A comparison of techniques in the assessment of chest wall thickness and composition

The thickness and composition of defined regions of the anterior chest wall are important factors in the assessment of pulmonary plutonium by low-energy x ray counting. Estimates of these quantities are reported for seven male subjects investigated by three laboratories using ultrasonic methods and by a fourth laboratory using magnetic resonance imaging. No important bias was found in any one laboratory's estimates of chest wall thickness relative to those of the others, but differences of up to 6 mm were noted for individual subjects. The discrepancies are believed principally to reflect the different sampling regimes adopted to reach a representative mean chest wall thickness over the region of interest from measurements at selected points. The adipose-tissue component was consistently found to be lower when assessed by magnetic resonance imaging compared with estimates by ultrasound, but the differences were unimportant in the context of plutonium assessment.

Thalassemia minor: a risk factor for osteoporosis?

A case report of a 53 year old postmenopausal woman with severe osteoporosis occurring in association with beta thalassemia trait is presented. She was found to have marked axial osteopenia with lumbar spine bone mineral density that was more than three standard deviations below the mean, but had normal bone mineral density of the proximal radius. A biopsy of the iliac crest showed evidence of high turnover osteoporosis. Bone densitometry of the spine and hip in a consecutive series of eleven asymptomatic individuals with thalassemia trait also is reported. Bone mineral density was diminished in the spine (z-score = -0.78, P less than 0.03) and hip (z-score = -0.54, P = 0.05) of patients with thalassemia trait. It is postulated that thalassemia minor may be a risk factor for osteoporosis.

Radioimmunodetection of degranulated human eosinophils in mice: a potential model for imaging Hodgkin's disease and other pathologic conditions

Various human tumors such as lymphomas and carcinomas sometimes contain extensive infiltration by degranulating eosinophils. To determine if degranulated eosinophils are suitable targets for immunolocalization, we performed in vivo distribution and imaging studies in mice, using EOS (a murine monoclonal antibody directed to human eosinophil peroxidase) labeled with indium-111. Adult mice were injected intravenously with radiolabeled EOS antibody or with similarly radiolabeled normal mouse IgG before receiving an intramuscular injection into the right thigh of homogenized human eosinophils adsorbed to latex microspheres. There was striking localization in the right thigh of the radiolabeled EOS antibody detectable by gamma imaging techniques as soon as 24 hr after injection. By contrast, there was little accumulation of radiolabeled normal IgG in the right thigh. We conclude that human eosinophil peroxidase is potentially a suitable target for radioimmunodetection and therapy of neoplasms and pathologic conditions that contain degranulating eosinophils.

The sclerotic pedicle--how many causes are there?

The sclerotic pedicle is a commonly encountered roentgen sign that may be associated with numerous conditions, both benign and malignant. The following paper discusses the common as well as the unusual causes of this interesting phenomenon and demonstrates the radiographic presentations of the various etiologies.

Are dolls real? Developmental changes in the child's definition of reality

Preschoolers (n = 20), second graders (n = 20), fifth graders (n = 20), and graduate-level college students (n = 20) were asked to determine the reality status of specific items, such as dolls and dreams, and to generate examples of real and not-real things. The criteria used for determining whether or not specific items were real differed significantly across the age range sampled and were strongly influenced by the type of items being judged. Criteria clearly changed with age, with item-specific criteria being substituted for more general verification criteria.

Echocardiographic diagnosis of right atrial thromboembolism

In a patient with congestive cardiomyopathy who died suddenly from right ventricular thromboembolism, antemortem two-dimensional echocardiography demonstrated a right atrial mass with acoustic characteristics suggestive of a thromboembolus. These characteristics included an elongated structure that assumed multiple dynamic forms and lack of an intracardiac attachment point. Because of the high likelihood of right ventricular impaction of a cardiac embolus, an aggressive therapeutic approach to such lesions is advised.

Myelodyspoietic syndrome associated with diethylstilbestrol therapy

We describe a patient with a myelodysplastic syndrome characterized by pancytopenia and an excess of myeloblasts in the bone marrow. He had received massive doses of diethylstilbestrol (150 mg daily) for seven years as therapy for prostatic carcinoma. Although myelodyspoiesis has been associated with other drugs, a relationship to estrogen therapy in man has not been reported previously. However, the administration of estrogens to animals has produced pancytopenia with a relative monocytosis and vacuolization of leukocytes. Examination of bone marroa, erythroid hypoplasia, and, with prolonged therapy, aplastic anemia. Further animal studies have demonstrated that estrogens exert a suppressive effect on marrow stem cells and granuloid progenitor cells. These experimental observations suggest a possible role of estrogens in the genesis of the hematologic changes we observed.

On-line data acquisition system for acoustic emission signals

An electronic system for processing and recording some very important parameters of acoustic emission signals at a relatively high speed is described. The system is applicable to almost any process in which acoustic emission is implemented for quality control. Data processing is done in real time. The processed data are ring-down count (threshold crossing), energy, duration, and time of occurrence of each acoustic emission burst.

Development of an automated form generating system for menu item data

At the University of Missouri-Columbia, an Automated Form Generating System consisting of six computer programs was developed to generate the master menu, production forecast and usage forms, production worksheet, food order report, and selective menus for patients. In the initial testing of the programs, this computer-assisted system showed a 30 per cent reduction in time requirred by dietitians and clerks when compared with the manual system. Some expected benefits include ease in making menu changes, substantial reduction in errors, automatic updating of documents, and reduction in storage space for forms because documents will be generated just prior to a production week. The system will be implemented at a later date.