In-Line Ultrasound-Enhanced Raman Spectroscopy Allows for Highly Sensitive Analysis with Improved Selectivity in Suspensions.

Raman spectroscopy is a nondestructive characterization method offering chemical-specific information. However, the cross-section of inelastically (Raman) scattered light is very low compared to elastically (Rayleigh) scattered light, resulting in weak signal intensities in Raman spectroscopy. Despite providing crucial information in off-line measurements, it usually is not sensitive enough for efficient, in-line process control in conjunction with low particle concentrations. To overcome this limitation, two custom-made 1.4404 stainless-steel prototype add-ons were developed for in-line Raman probes that enable ultrasound particle manipulation and thus concentration of particles in suspensions in the focus of the Raman excitation laser. Depending on size and density differences between particles and the carrier medium, particles are typically caught in the nodal planes of a quasi-standing wave field formed in an acoustic resonator in front of the sensor. Two arrangements were realized with regard to the propagation direction of the ultrasonic wave relative to the propagation direction of the laser. The parallel arrangement improved the limit of detection (LOD) by a factor of ≈30. In addition to increased sensitivity, the perpendicular arrangement offers increased selectivity: modifying the frequency of the ultrasonic wave field allows the liquid or solid phase to be moved into the focus of the Raman laser. The combination of in-line Raman spectroscopy with ultrasound particle manipulation holds promise to push the limits of conventional Raman spectroscopy, hence broadening its field of application to areas where previously Raman spectroscopy has not had sufficient sensitivity for accurate, in-line detection.

An Acoustic Trap for Bead Injection Attenuated Total Reflection Infrared Spectroscopy.

In this work, we introduce a system combining an acoustic trap for bead injection with attenuated total reflection (ATR) infrared (IR) spectroscopy. By mounting an acoustofluidic cell hosting an ultrasound source on top of a custom-built ATR fixture we were able to trap beads labeled with the enzyme alkaline phosphatase without requiring any mechanical retention elements. Sequential injection analysis was employed for reproducible sample handling and bead injection into the acoustic trap. To showcase potential applications of the presented setup for kinetic studies, we monitored the conversion of p-nitrophenylphosphate into p-nitrophenol and phosphate via beads carrying the immobilized enzyme using ATR-IR spectroscopy. Retaining the labeled beads via ultrasound particle manipulation resulted in excellent experimental reproducibility (relative standard deviation, 3.91%). It was demonstrated that trapped beads remained stably restrained with up to eight cell volumes of liquid passing through the acoustofluidic cell. Beads could be discarded in a straightforward manner by switching off the ultrasound, in contrast to systems containing mechanical retention elements, which require backflushing. Multiple experiments were performed by employing different substrate concentrations with the same batch of trapped beads as well as varying the amount of enzyme present in the cell, enabling enzyme kinetic studies and emphasizing the application of the proposed setup in studies where enzymatic reuse is desired. This proves the potential of the acoustic trap combined with ATR-IR spectroscopy to monitor the activity of immobilized enzymes and its ability to perform complex bead-based assays.

Epiphyseal hyperplasia caused by an ectopic ossification center of the distal tibia: presentation of a pediatric case with 13 years of radiological surveillance.

Herein, we report the case of a 4-year-old boy, who presented with a cortical lytic lesion of his distal tibia. It was located eccentrically, measured 2 cm in its craniocaudal diameter, and was associated with a lamella-like soft-tissue mineralization that resembled a periosteal reaction. Thus, the lesion's radiographic features were initially suggestive of an aggressive disease. However, further imaging revealed the lesion to be of cartilaginous origin and to extend into the metaphysis, thus creating the aspect of hyperplastic epiphyseal cartilage. This cartilaginous hyperplasia was likely caused by an ectopic ossification center, although no similar cases have yet been reported. As radiology and clinics no longer indicated the imminent threat of a high-grade malignancy, we decided against a biopsy to avoid interfering with epiphyseal growth. However, because of the unprecedented nature of the given constellation, we closely monitored the lesion radiologically to rule out an untypical manifestation of a benign but potentially expanding lesion, in addition to a growth disturbance resulting from the lesion itself. However, further imaging indicated that mineralization and ossifications, which were already present at the lesion's initial presentation, increased over time, until the lesion fully disappeared after 13 years of clinical and radiological surveillance. This case is outstanding because of its singular morphology and the long-term follow-up that illustrates its self-limiting natural course. This report provides support in differential diagnosis to help discriminate potentially self-limiting conditions from other diseases that may require invasive diagnosis and/or therapy.

MALT lymphoma of the paranasal sinuses and the hard palate: report of two cases and review of the literature.

Extra-nodal low-grade B-cell lymphomas arising in the gastrointestinal tract recapitulate the structure and features of mucosa-associated lymphoid tissue, called "MALT lymphomas." In the head and neck region except for the salivary glands the occurrence of this neoplasm is very rare. The authors report on two such cases of MALT lymphoma, one of the hard palate in a 71-year-old woman and the other of the paranasal sinuses in a 69-year-old woman with the history of chronic sinusitis. Such chronic inflammatory conditions can induce the development of MALT lymphoma. Clinical elaboration should include computerized tomography (CT) and magnetic resonance imaging (MRI) for the assessment of tumor extension, bone destruction, lymph node involvement and differentiation of mucosal thickening from tumor mass. Biopsy for histopathological diagnosis is mandatory. Treatment should be surgery, irradiation or combined radio-chemotherapy depending on the stage of the disease.

Microvascular in vivo assessment of reperfusion injury: significance of prostaglandin E(1) and I(2) in postischemic "no-reflow" and "reflow-paradox".

BACKGROUND: Microvascular ischemia-reperfusion (I/R) injury is characterized by failure of capillary perfusion ("no-reflow") and reoxygenation-associated phenomena ("reflow-paradox"), including activation of leukocyte-endothelium interaction with cytotoxic mediator-induced loss of endothelial integrity. The objectives of this study were to elucidate the impact of both prostaglandins E(1) (PGE(1)) and I(2) (PGI(2)) in microvascular reperfusion injury, with special focus on the distinct pathophysiology of no-reflow- and reflow-paradox phenomena. MATERIALS AND METHODS: By use of the hamster dorsal skinfold preparation and in vivo fluorescence microscopy, the microcirculation of a striated skin muscle was assessed before 4 h of pressure-induced ischemia and 0.5, 2, and 24 h after onset of reperfusion. RESULTS: I/R was characterized by enhanced leukocyte-endothelium interaction in postcapillary venules, increase of macromolecular leakage, and reduction of functional capillary perfusion (P < 0.05). Intravenous 2-h infusion of PGE(1), starting with onset of reperfusion, reduced leukocyte adhesion and macromolecular leakage in postcapillary venules during early reperfusion (P < 0.05), while 6-h infusion, given during ischemia and early reperfusion, showed no significant effects. PGI(2) infusion also attenuated postischemic leukocyte adhesion, which was significant by a 6-h prolonged administration (P < 0.05), but did not influence the increase of microvascular permeability. Both prostaglandins were unable to prevent the postischemic failure of capillary perfusion (no-reflow). CONCLUSIONS: Both prostaglandins did not significantly influence postischemic no-reflow phenomena, but appeared as potent inhibitors of reflow-paradox under the experimental circumstances of this study.

Diagnosis and management of carcinoma of unknown primary in the head and neck.

Carcinoma of unknown primary is defined as the histological diagnosis of metastasis without the detection of a primary tumor. In the literature, the incidence of CUP in all patients with a malignant disease is said to be between 3% and 15%. The most frequent histopathological results of CUP metastases are adenocarcinoma, followed by undifferentiated carcinoma and squamous cell carcinoma. In this retrospective investigation the clinical records of 167 patients were studied. All patients had been admitted and treated for cervical CUP at the Department of Otorhinolaryngology of the Grosshadern Clinic from 1979 to 1998. Cervical swelling was the first noted symptom in all cases, followed by pain and dysphagia. The study group comprised 134 men and 33 women with an average age of 55 years at admission. Squamous cell carcinoma (n=123) was the predominant histopathological finding of the cervical lymph nodes. During the 10-year follow-up, a primary tumor was detected in 36 (21.5%) of the 167 initially diagnosed CUP patients. In over 90% of these cases the tumor was localized in the head and neck region. The most frequent origin of the tumor was the tonsilla palatina (n=7). Neck dissection and additional postoperative radiotherapy was performed in 118 (70.7%) of the 167 CUP patients. Primary radiotherapy was the treatment of choice in 28 patients; eight patients received combined radio-chemotherapy as the primary treatment and seven patients were treated with chemotherapy alone. Six patients had no treatment. Comparison of different treatment protocols revealed a significant difference in patient survival: in comparison with primary radiotherapy alone or neck dissection and postoperative radiotherapy, the survival rate improved significantly in patients that received a bilateral tonsillectomy in addition to neck dissection and postoperative radiotherapy. The treatment of choice in patients with cervical CUP should be a surgical procedure including (radical) neck dissection and diagnostic bilateral tonsillectomy followed by postoperative radiation of the cervical lymph drainage. Bilateral tonsillectomy is especially important and is correlated with a significant improvement of the survival rate in CUP patients. Additional postoperative radiation of the entire pharyngeal and laryngeal mucosa should also be considered in order to treat a possible small primary tumor in this region.

Association of laryngopharyngeal symptoms with gastroesophageal reflux disease.

OBJECTIVES: The prevalence of gastroesophageal reflux disease (GERD) in patients with laryngopharyngeal disorders is probably greater than realized. STUDY DESIGN: Prospective study. METHODS: To investigate the incidence of gastroenterological diseases including GERD in patients complaining of nonspecific laryngopharyngeal symptoms, laryngological examinations and gastroenterological evaluation with esophagogastroduodenoscopy were performed in 30 patients who refused to undergo 24-hour pH monitoring. Therapeutic intervention by behavioural and dietary modifications, antireflux medication, and eradication of Helicobacter pylori were assessed for changes in laryngeal findings and relief of symptoms. RESULTS: Posterior laryngitis was present in 26 patients and in 19 of them was accompanied by erythema and edema of the interarytenoid region. Gastroenterological diseases such as GERD (43%), hiatal hernia (43%), and Helicobacter pylori-positive antrum gastritis (23%) were confirmed in 22 (73%) cases by esophagogastroduodenoscopy and histological examination of biopsy specimens. Medical antireflux treatment and eradication of Helicobacter pylori resulted in a remarkably therapeutic success rate of 90% because there was resolution of laryngopharyngeal symptoms and laryngeal findings in 20 of 22 patients with gastroenterological diseases for the mean follow-up period of 8 months. CONCLUSIONS: Laryngopharyngeal symptoms can be predictors of gastroesophageal diseases and GERD because the most frequent underlying cause is supposed to be associated with posterior laryngitis. Medical antireflux treatment is effective for relief of symptoms and mucosal healing of posterior laryngitis.