On the Relationship between Dynamic Contrast-Enhanced Ultrasound Parameters and the Underlying Vascular Architecture Extracted from Acoustic Angiography

Dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as a powerful tool for cancer diagnosis by estimation of perfusion and dispersion parameters reflecting angiogenic vascular changes. This work was aimed at identifying which vascular features are reflected by the estimated perfusion and dispersion parameters through comparison with acoustic angiography (AA). AA is a high-resolution technique that allows quantification of vascular morphology. Three-dimensional AA and 2-D DCE-US bolus acquisitions were used to monitor the growth of fibrosarcoma tumors in nine rats. AA-derived vascular properties were analyzed along with DCE-US perfusion and dispersion to investigate the differences between tumor and control and their evolution in time. AA-derived microvascular density and DCE-US perfusion exhibited good agreement, confirmed by their spatial distributions. No vascular feature was correlated with dispersion. Yet, dispersion provided better cancer classification than perfusion. We therefore hypothesize that dispersion characterizes vessels that are smaller than those visible with AA.     

New insights on COPD imaging via CT and MRI

Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD.     

Oxidative metabolism of lung macrophages exposed to sodium arsenite

Arsenic pollution has become increasingly severe. It occurs as the result of geological processes and different human activities. Arsenic toxicity at the respiratory level occurs mainly by inhalation of products of coal combustion. The aim of this study was to evaluate sodium arsenite (As³⁺) toxicity in murine alveolar macrophages (AMs) in vitro and its association with the alterations in cell metabolism.

No changes in viability, apoptosis or cell area were detected in AMs treated with As³⁺ concentrations up to 2 μM for 24–96 h. A marked decrease in these end-points was observed for As³⁺ concentrations ranging from 2.5 μM to 10 μM.

Regarding the dynamics of the endo-exocytic process triggered by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell incorporation, no variations were detected for As³⁺ concentrations lower than 2 μM while higher concentrations markedly modified this response.

MTT specific activity, as a measure of cell metabolic activity, was not modified irrespective of the As³⁺ concentration assayed. However, nitroblue tetrazolium (NBT) specific activity, as a measure of superoxide anion generation, is responsive but only to low As³⁺ doses.

Although this study focuses on lung macrophages, the effects of As³⁺ described herein may also apply to the response of macrophages residing in other organs.

Arsenite modifies the metabolic and the oxidative status of AMs in vitro. When macrophages are in an As³⁺ rich medium, they exhibit a reduction in respiratory burst levels and lose their intrinsic capacity to respond to toxicants.     

Usefulness of gallium 67 in research into the need for radical cervical lymph node dissection in patients with head and neck carcinomas

Fifty-nine patients with head and neck carcinoma were examined with 67Ga scintigraphy. All patients had undergone lymph node dissection of the neck. They were followed for a minimum of 2 years after the examination. The primary tumor, treated prior/contemporaneously to the lymph node dissection, did not evolve in this interval. Metastatic involvement of the lymph node capsule was observed in all 44 cases with metastatic lymph nodes; macroscopic radicality was surgically obtained since involvement of the capsule was only microscopic. Nevertheless, complementary radiotherapy was given. The whole of 17 recurrences in the soft tissues of the neck were found, within 2 years, in the group of 26 patients who had undergone dissection of lymph nodes with metastatic capsular involvement and whose postoperative 67Ga scintigraphy was positive. On the contrary, no recurrences in the soft tissues of the neck were observed in the group of 18 patients who had undergone dissection of lymph nodes with metastatic capsular involvement and whose scintigraphy was negative. This result proves (P less than 0.001) 67Ga capable of evidencing eventual microscopic diffusion. Such a possibility has not yet been realized in vivo with any other investigation technique. Scintigraphy was negative in a control group of 15 patients who had undergone lymph node dissection, and with nonmetastatic lymph nodes. This finding leads us to exclude that the use of 67Ga might result in misinterpreted findings in the exploration of relatively superficial tissues. In fact, the eventual accumulation of radioisotope in nonneoplastic pathologies is quite easily recognizable in the neck. We can therefore conclude that in those 9 cases with positive scintigraphy and in whom no recurrence was found, microscopic diffusion was probably present, but local recurrence of the disease was prevented by complementary radiotherapy.     

Microbial penetration of gloves following usage in routine dental procedures.

Unsterile polyvinyl, regular latex, and powder-free, modified latex examination gloves were evaluated following usage in routine dental procedures to assess their loss of integrity. Glove fingers were filled with a suspension of red-pigmented Serratia marcescens and drawn across the surface of tryptic soy agar plates. The appearance of red-pigmented Serratia colonies on the plates was used as an indication of glove defects. Unused, unwashed gloves taken at random from boxes served as controls. Of the gloves used in clinical procedures, 83.3% of the polyvinyl gloves, 35.0% of the regular latex gloves, and 7.5% of the powder-free, modified latex gloves allowed penetration of Serratia. Data thus suggest that advances in technology continue to develop a glove with more resistance than regular latex and vinyl gloves to routine clinical usage.     

Proteolytic activity of the purified hormone-binding subunit in the estrogen receptor.

The hormone-binding subunit of the calf uterus estradiol receptor was purified as a hormone-free molecule. Immunoaffinity chromatography with a specific monoclonal antibody was used as the final step. The purified subunit was specifically labeled by radioactive diisopropyl fluorophosphate. The diisopropyl fluorophosphate-labeled amino acid was serine. The purified receptor was able to release the fluorogenic or chromogenic group from synthetic peptides containing phenylalanine at the carboxyl terminus. This occurred only in the presence of estradiol and was hampered by aprotinin and diisopropyl fluorophosphate. Estradiol-dependent hydrolytic activity was also found in the eluate from gel slices after SDS/PAGE of purified receptor. This activity comigrated with the renaturable estradiol-binding activity. The estradiol antagonists 4-hydroxytamoxifen and ICI 164,384 as well as other steroid hormones were unable to activate this hydrolytic activity.     

Increased risk of necrotizing enterocolitis in premature infants with patent ductus arteriosus treated with indomethacin.

OBJECTIVE: The authors evaluated the risk of necrotizing enterocolitis (NEC) in very low birth weight infants receiving indomethacin (INDO) to close patent ductus arteriosus (PDA). BACKGROUND DATA: Controversy exists regarding the best method of managing very low birth weight infants with PDA and whether to employ medical management using INDO or surgical ligation of the ductus. METHODS: Two hundred fifty-two premature infants with symptomatic PDA were given intravenously INDO 0.2 mg/kg every 12 hours x 3 in an attempt to close the ductus. Patients were evaluated for sex, birth weight, gestational age, ductus closure, occurrence of NEC, bowel perforation, and mortality. RESULTS: There were 135 boys and 117 girls. The PDA closed or became asymptomatic in 224 cases (89%), whereas 28 (11%) required surgical ligation. Ninety infants (35%) developed evidence of NEC after INDO therapy. Fifty-six were managed medically; surgical intervention was required in 34 of 90 cases (37.8%) or 13% of the entire PDA/INDO study group. Bowel perforation was noted in 27 cases (30%). Factors associated with the onset of NEC included gestational age < 28 weeks, birth weight < 1 kg, and prolonged ventilator support. The overall mortality rate was 25.5%, but was higher in infants with NEC versus those without. The highest mortality was noted in perforated NEC cases. The PDA/INDO patients were compared with a control group of 764 infants with similar sex distribution, birth weights, and gestational ages without PDA who did not receive INDO. Necrotizing enterocolitis occurred in 105 of 764 control patients (13.7%), including 13 (12.3%) with perforation. The overall mortality rate of controls was 25%, which was similar to the overall 25.5% mortality rate in the PDA/INDO study group. CONCLUSION: These data indicate that there is increased risk of NEC and bowel perforation in premature infants with PDA receiving INDO. Mortality was higher in the PDA/INDO group with NEC than those PDA/INDO infants without NEC.     

Infection control is more than just extra inventory.

Communication of infection-control practices is an overlooked area of practice management. Often, people forget to consider the training, time, and expense associated with the wide variety of protocols, techniques, and regimens. Explore and develop approaches aimed at conveying the infection-control practices you use to other care providers and your patient family. When these are used appropriately, you serve both patients and the community in the capacity for which you were trained--as a health-care professional. It does not get any better than that!     

Secondary generalized epilepsy in childhood: EEG patterns and correlation with responsiveness to benzodiazepines or ACTH (preliminary note)

Secondary generalized epilepsy in childhood, characterized by absences or minor motor seizures, occurs in the forms of various syndromes, as defined by current classifications. EEG often shows continuous or subcontinuous paroxysmal activity associated with partly reversible psychomotor or mental regression. The paroxysmal activity can exhibit one of two distinct patterns: "organized" or "disorganized," although intermediate forms are common. The two patterns differ not only morphologically but also in the responsiveness to drug or hormone therapy, reactivity to stimuli, sleep changes and frequency of disordered slow rhythms. These features are illustrated by means of a survey of 10 cases.