Multi-Wavelength Photoacoustic Visualization of High Intensity Focused Ultrasound Lesions

High intensity focused ultrasound (HIFU) thermal therapies are limited by deficiencies in existing image-guidance techniques. Previous studies using single-wavelength photoacoustic (PA) imaging have demonstrated that HIFU lesions generate contrast with respect to native tissues but have not sufficiently assessed lesion extent. The purpose of this study is to demonstrate feasibility of characterization of in vitro HIFU ablation lesion dimensions using 3D multi-wavelength PA imaging. Fresh porcine cardiac and liver tissue samples were embedded in agar phantoms and ablated using a 2.5 MHz small-animal HIFU system. Both 2D and 3D multi-wavelength photoacoustic-ultrasonic (PAUS) scans were performed in the near-infrared (NIR) range to characterize the change in the absorption spectrum of tissues following ablation and were compared to stained gross pathology to assess treatment margins and lesion extent. Comprehensive 2D multi-wavelength PA imaging yielded a spectrum in ablated tissue that did not display the characteristic local maximum in the optical absorption spectrum of deoxy-hemoglobin (Hb) near 760 nm. Two-dimensional tissue characterization map (TCM) images reconstructed from 3D TCM volumes reliably characterized lesion area and showed >70% area agreement with stained gross pathology. In addition, tissue samples were heated via water bath and concurrently interrogated with 2D PAUS imaging. PA signal exhibited an initial amplitude increase across all wavelengths, corresponding to an initial temperature increase, before then exhibiting a spectral change. This study suggests that multi-wavelength PA imaging has potential to obtain accurate characterization of HIFU lesion extent and may be better suited to guide HIFU ablation therapies during clinical treatments than single-wavelength methods.

The appearance of pili annulati following alopecia areata

Pili annulati is a rare autosomal-dominant hair shaft abnormality. It is characterized by alternating light and dark bands along the shaft due to air-filled cavities within the cortex of the hair shaft. Alopecia areata has been previously described as a common association with pili annulati, with improvement in alopecia areata coinciding with resolution of pili annulati. We report the case of a patient with a history of alopecia areata and alopecia universalis who developed the characteristic banded hair of pili annulati upon resolution of her alopecia areata. We provide direct microscopic examination of postregrowth hairs compared to normal and cross-polarized light microscopy.

Scrotal pain in the absence of torsion; need for vigilance

Epididymitis is a common presentation of acute testicular pain seen in the emergency department, the differential diagnosis being testicular torsion. The vast majority of young men with epididymitis have an infective aetiology and this settle with antibiotic treatment. The clinical course of a patient who presented with testicular pain is described. At ultrasonography, the patient was found to have the uncommon condition of testicular microlithiasis, a condition that has been linked to malignant disease. Emergency doctors should be aware of the potential consequences of returning scrotal pain consistent with epididymitis to the community on antibiotic treatment alone. All patients with probable epididymitis should have either a scrotal ultrasound or specialist follow up.

Reservoir competence of Carcinops pumilio for Salmonella enteritidis (Eubacteriales: Enterobacteriaceae)

The histerid beetle Carcinops pumilio (Erichson) occurs naturally in poultry house manure and is an important predator of house fly eggs and larvae. Because efforts to commercially produce C. pumilio have been unsuccessful, one fly control strategy under consideration is the direct transport of adult C. pumilio between poultry houses to facilitate their establishment. However, we demonstrate that C. pumilio is a competent reservoir of Salmonella enteritidis (Gaertner). Adult C. pumilio exposed to S. enteritidis-inoculated house fly eggs harbored the bacterium externally and internally for up to 4 and 13 d, respectively, and feces were culture-positive for S. enteritidis for at least 14 d. This suggests that C. pumilio can be a reservoir of S. enteritidis; therefore its movement between poultry facilities should be carefully considered.

Co-compartmentalization of MAP kinases and cytosolic phospholipase A2 at cytoplasmic arachidonate-rich lipid bodies

Lipid bodies are inducible lipid domains abundantly present in leukocytes engaged in inflammation. They are rich in esterified arachidonate and are also potential sites for eicosanoid-forming enzyme localization. It is therefore of interest to know whether arachidonate-releasing cytosolic phospholipase A2 (cPLA2) localizes at lipid bodies. Here, we present evidence that cPLA2 and its activating protein kinases, mitogen-activated protein (MAP) kinases, co-localize at lipid bodies. U937 cells express high levels of cPLA2 and contain numerous cytoplasmic lipid bodies. Using double-labeling immunocytochemistry we demonstrated punctate cytoplasmic localizations of both cPLA2 and MAP kinases in U937 cells that were perfectly concordant with fluorescent fatty-acid-labeled lipid bodies. The co-localization of cPLA2 and MAP kinases at lipid bodies was confirmed by subcellular fractionation and immunoblot. Lipid body fractions free of cytosol and other organelles contained significant amounts of [14C]arachidonate-labeled phosphatidylcholine and cPLA2 enzymatic activities. Immunoblotting with specific antibodies identified cPLA2 as well as MAP kinases, including ERK1, ERK2, p85, and p38, in lipid bodies. The co-compartmentalization within arachidonate-rich lipid bodies of cPLA2 and its potentially activating protein kinases suggests that lipid bodies may be structurally distinct intracellular sites active in extracellular ligand-induced arachidonate release and eicosanoid formation.

Phylogenetic analysis of the bacterial communities in marine sediments

For the phylogenetic analysis of microbial communities present in environmental samples microbial DNA can be extracted from the sample, 16S rDNA can be amplified with suitable primers and the PCR, and clonal libraries can be constructed. We report a protocol that can be used for efficient cell lysis and recovery of DNA from marine sediments. Key steps in this procedure include the use of a bead mill homogenizer for matrix disruption and uniform cell lysis and then purification of the released DNA by agarose gel electrophoresis. For sediments collected from two sites in Puget Sound, over 96% of the cells present were lysed. Our method yields high-molecular-weight DNA that is suitable for molecular studies, including amplification of 16S rRNA genes. The DNA yield was 47 micrograms per g (dry weight) for sediments collected from creosote-contaminated Eagle Harbor, Wash. Primers were selected for the PCR amplification of (eu)bacterial 16S rDNA that contained linkers with unique 8-base restriction sites for directional cloning. Examination of 22 16S rDNA clones showed that the surficial sediments in Eagle Harbor contained a phylogenetically diverse population of organisms from the Bacteria domain (G. J. Olsen, C. R. Woese, and R. Overbeek, J. Bacteriol. 176:1-6, 1994) with members of six major lineages represented: alpha, delta, and gamma Proteobacteria; the gram-positive high G+C content subdivision; clostridia and related organisms; and planctomyces and related organisms. None of the clones were identical to any representatives in the Ribosomal Database Project small subunit RNA database. The analysis of clonal representives in the first report using molecular techniques to determine the phylogenetic composition of the (eu)bacterial community present in coastal marine sediments.

Cycloclasticus pugetii gen. nov., sp. nov., an aromatic hydrocarbon-degrading bacterium from marine sediments

Three heterotrophic bacterial strains were isolated from different locations in Puget Sound, Washington, by using biphenyl as the principal carbon source. These strains grow by using a limited number of organic compounds, including the aromatic hydrocarbons naphthalene, phenanthrene, anthracene, and toluene, as sole carbon sources. These aerobic, gram-negative rods are motile by means of single polar flagella. Their 16S rRNA sequences indicate that they are all members of the gamma subdivision of the Proteobacteria. Their closet known relatives are the genera Methylobacter and Methylomonas (genera of methane-oxidizing bacteria), uncultured sulfur-oxidizing symbionts found in marine invertebrates, and clone FL5 containing 16S ribosomal DNA amplified from an environmental source. However, the Puget Sound bacteria do not use methane or methanol as a carbon source and do not oxidize reduced sulfur compounds. Furthermore, a 16S rRNA base similarity comparison revealed that these bacteria are sufficiently different from other bacteria to justify establishment of a new genus. On the basis of the information summarized above, we describe a new genus and species, Cycloclasticus pugetti, for these bacteria; strain PS-1 is the type strain of C. pugetti.

Organising the MRCP exam--a guide for registrars

Taking the MRCP exam as a candidate can be traumatic. For the registrar who has to organise one, the task may be just as daunting. Efficient coordination of candidates, patients and examiners and the provision of good clinical material in a suitable setting requires considerable organisation. This supplement to the guide issued by the College, based on our own experience, describes in more detail the preparation and management of the examination in the hope that it will ease our colleagues' tasks.

The Salmonella typhimurium nadC gene: sequence determination by use of Mud-P22 and purification of quinolinate phosphoribosyltransferase

The Salmonella typhimurium nadC gene and its product, quinolinic acid phosphoribosyltransferase (QAPRTase), were characterized at the molecular and biochemical levels. Fusions of Mud-lac elements isolated in the nadC gene were converted to Mud-P22 insertions. Starting with six original Mud-lac fusions, the entire sequence of the nadC gene was readily obtained. The sequence shows a long open reading frame with two potential initiator methionines, one of which is preceded by the Shine-Dalgarno sequence GGAG-7-nucleotide-ATG. The protein predicted from this second open reading frame is 297 residues in length. The nadC gene was subcloned into a T7-based expression system, allowing for facile purification of the QAPRTase (EC 2.4.2.19) protein to homogeneity. Upon gel filtration, the protein gave an M(r) of 72,000, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis gave a subunit M(r) of 35,000. Automated Edman degradation of several tryptic peptides confirmed the amino acid sequence predicted from the DNA sequence. Chromatography of the apparently homogeneous enzyme on reverse-phase high-performance liquid chromatography resolved two protein species. One of these species failed to give an amino-terminal sequence, while the other yielded the amino-terminal sequence predicted by the second open reading frame and lacked the initiator methionine. The mass of the mature protein, predicted from its DNA sequence, was 32,428 Da. Electrospray mass spectrometry gave masses of 32,501 and 32,581 Da for the two peptides. Steady-state kinetics on the purified QAPRTase indicated Km values of 32 microM for 5-phosphoribosyl-1-pyrophosphate and 20 microM for quinolinate. Vmax was 0.9 U/mg, similar to values reported for this enzyme by other sources.

Use of Peldri II (a fluorocarbon solid at room temperature) as an alternative to critical point drying for biological tissues

A new chemical, Peldri II, is evaluated as a compound for drying soft biological tissues for scanning electron microscopy. Peldri II, a fluorocarbon, is a solid at room temperature and is a liquid above 25 degrees C. Cells or tissues are embedded in Peldri II by immersing them in the liquid form and allowing it to solidify. Once solidified, Peldri II will sublime with or without vacuum to dry tissues, probably without introducing surface tension. Several types of cells and tissues have been examined to compare preservation with Peldri II and critical point drying techniques. No differences were detected between the two techniques when normal surface structures were examined. Peldri II appears to be a significant improvement over hexamethyldisilazane as a drying agent for scanning electron microscopy. It is also very convenient for drying large numbers of samples.

Hepatic oxidative drug metabolism and the microsomal milieu in a rat model of congenital hyperbilirubinemia

The aims of this study were to evaluate the hypothesis that impaired glucuronidation of bilirubin and possibly of drug oxidation in the liver of homozygous (jj) Gunn rats may be due to an altered microsomal milieu. Accordingly, we investigated and compared in vivo and in vitro demethylation of aminopyrine, hepatic cytochrome P-450 levels, microsomal lipid composition, and microsomal membrane fluidity in icteric, homozygous (jj) Gunn rats and in their anicteric heterozygous (jJ) littermates. In both males and females, [14C]aminopyrine demethylation in vivo, using the 14CO2 breath test, was unimpaired in the icteric animals. Likewise, cytochrome P-450 levels in the icteric and nonicteric groups were similar, and aminopyrine kinetics in vitro in the females were comparable in icteric and nonicteric littermates. The main lipid classes were also similar in the homozygous and heterozygous female Gunn rats, whereas only minor changes were seen in the phospholipid fatty acyl composition with a small, but significant, increase in the unsaturated index in the icteric group. Despite this, there was no apparent effect on hepatic microsomal membrane fluidity as measured by the order parameter of I[12,3] and the rotational correlation time of I[1,14] in either female or male sets of homozygous and heterozygous Gunn rats. Our data, therefore, do not support an alteration of composition or fluidity of the microsomal milieu as a mechanism of impaired bilirubin glucuronidation and possibly of oxidation in these animals. They also absolve long-term unconjugated hyperbilirubinemia as a mechanism of hepatic microsomal dysfunction. Our study, therefore, indirectly suggests that abnormal glucuronidation of bilirubin and some other aglycones in homozygous Gunn rats is due to genetic abnormalities involving the enzyme(s) itself.

The influence of female power in marriage on sexual behaviors and attitudes: a holocultural study

Abernethy (1974) hypothesized that the quality and quantity of sexual activity within marriage is affected by the dominance relations between partners. This paper reviews her argument and the reactions it engendered. A holocultural test of the relationship between a wife's power within marriage and various measures of sexual behaviors and attitudes is conducted to explore one aspect of Abernethy's position. The results suggest that high levels of female power within marriage do not have an adverse affect on male sexual functioning. Results also indicate that societies characterized by high female power within marriage exhibit behaviors and attitudes which Western thought sees as sexually "healthy."

Effects of ethanol in vitro on rat intestinal brush-border membranes

Ethanol, at concentrations found in the intestinal lumen after moderate drinking, has been shown to inhibit carrier-mediated intestinal transport processes. This inhibition could occur by direct interaction with membrane transporters, dissipation of the energy producing Na+ electrochemical gradient and/or nonspecific alteration of membrane integrity. The latter alteration may be reflected by changes in membrane fluidity, chemical composition or vesicular size. These possibilities were examined with studies in purified brush border membrane vesicles of rat intestine. Ethanol inhibited concentrative Na+-dependent D-glucose uptake in a dose-dependent manner. In contrast, ethanol did not inhibit concentrative D-glucose uptake under conditions of D-glucose trans-stimulation in the absence of a Na+ electrochemical gradient. Ethanol also inhibited initial, concentrative Na+-dependent taurocholic acid uptake, as well as equilibrium uptake. That ethanol exerted a dual effect on transport by increasing membrane conductance for Na+ while decreasing intravesicular space was supported by direct studies of Na+ uptake. Morphometric analysis confirmed that ethanol-treated membranes had a decreased intravesicular size when compared to untreated membranes. Finally, membrane fluidity measured by EPR showed that ethanol had a significant fluidizing effect without producing qualitative changes in membrane proteins, as determined by SDS gel electrophoresis. These results suggest that ethanol inhibits carrier-mediated transport by dissipation of the Na+ electrochemical gradient and alteration of membrane integrity rather than by direct interaction with membrane transporter.

The doctor's family: some problems and solutions

Some sources of stress in the doctor's family are described and a number of solutions are offered. Problems which are common to all doctors' families are identified and others which relate to specific groups. Solutions are classified according to those which require self-help and those which are offered from outside. The practical possibility of groups for trainee wives is suggested as a means of prevention rather than cure.

Height and sexual dimorphism of stature among human societies

In this study, which is concerned with the varying degrees of sexual dimorphism of stature between human societies, adult male and female height measurements and male-female height ratios-the measure of sexual dimorphism-from 216 societies are statistically compared with several variables: marriage practices, protein availability, the presence of milking herbs, settlement size, and climate. Our results indicate that while greater mean male height is associated with polygynous marriage, marriage practices did not exert an influence on the degree of sexual dimorphism of stature. On the other hand, the results suggest that while sexual dimorphism in height has a strong genetic component, dietary factors can influence the degree of dimorphism.