Cardiac Calcium Evaluation in Hemodialysis Patients with Multisection Spiral Computed Tomography

Aim

The aim of this study is cardiac calcium content evaluation in hemodialysis patients by a new technique, based on ultrafast multisection CT (MTC).

Methods

The study was carried out on 30 HD patients, 14F and 16 M, average age 57.7±13.9 years, average HD age 57.3±47.4 months. The intact PTH levels were 625.4±571 pg/mL. Serum calcium, phosphate and CaxP product were 9.75±0.84 mg/mL, 6.21±1.01 mg/dL and 60.2±10.7 mg2/dL2, respectively.

Results

The values obtained with the MTC technique were reported in terms of Agatson scores. Score values frankly in the pathologic range (>100) were found in 24 patients (80%). Correlation analysis has shown positive and significant correlation coefficients of the score with patients’ age (p=0.003), serum calcium (p=0.012), CaxP (p=0.015), iPTH (=0.049), and borderline, to HD age (p=0.06).

Conclusion

Risk factors for cardiac calcification are mainly age, degree of hyperparathyroidism, increased CaxP and serum calcium levels. A control of calcium phosphate parameters in hemodialysis patients seems to be mandatory to avoid increased severity of coronary artery disease.

Presence of Herpes Simplex Virus on the Oral Mucosa in Patients Undergoing Chemotherapy

Background

The aim of this study was to confirm the presence of herpes simplex virus type 1 and 2 on the oral mucosa, in patients undergoing chemotherapy, by means of polymerase chain reaction (PCR).

Methods

The research was carried out on 40 patients receiving chemotherapy as treatment for different malignancies. The status of oral mucosa and viral presence were assessed in all patients at the initial examination (prior to chemotherapy), and at the control examination (two weeks after the initiation of the chemotherapeutic cycle).

Results

The presence of HSV-1 was detected in 28 patients (70%) prior to chemotherapy, of whom 7 (25%) manifested oral complications. The control examination showed the presence of HSV-1 in 35 patients (87.5%), of whom 23 (65.7%) presented oral mucosa changes. HSV-2 has not been detected in any of the patients.

In vivo three-dimensional photoacoustic imaging based on a clinical matrix array ultrasound probe

We present an integrated photoacoustic and ultrasonic three-dimensional (3-D) volumetric imaging system based on a two-dimensional (2-D) matrix array ultrasound probe. A wavelength-tunable dye laser pumped by a Q-switched Nd:YAG laser serves as the light source and a modified commercial ultrasound imaging system (iU22, Philips Healthcare) with a 2-D array transducer (X7-2, Philips Healthcare) detects both the pulse-echo ultrasound and photoacoustic signals. A multichannel data acquisition system acquires the RF channel data. The imaging system enables rendering of co-registered 3-D ultrasound and photoacoustic images without mechanical scanning. The resolution along the azimuth, elevation, and axial direction are measured to be 0.69, 0.90 and 0.84 mm for photoacoustic imaging. In vivo 3-D photoacoustic mapping of the sentinel lymph node was demonstrated in a rat model using methylene blue dye. These results highlight the clinical potential of 3-D PA imaging for identification of sentinel lymph nodes for cancer staging in humans.

Performance characterization of an integrated ultrasound, photoacoustic, and thermoacoustic imaging system

We developed a novel trimodality system for human breast imaging by integrating photoacoustic (PA) and thermoacoustic (TA) imaging techniques into a modified commercial ultrasound scanner. Because light was delivered with an optical assembly placed within the microwave antenna, no mechanical switching between the microwave and laser sources was needed. Laser and microwave excitation pulses were interleaved to enable PA and TA data acquisition in parallel at a rate of 10 frames per second. A tube (7 mm inner diameter) filled with oxygenated bovine blood or 30 mM methylene blue dye was successfully detected in PA images in chicken breast tissue at depths of 6.6 and 8.4 cm, respectively, for the first time. The SNRs at these depths reached ∼24 and ∼15 dB, respectively, by averaging 200 signal acquisitions. Similarly, a tube (13 mm inner diameter) filled with saline solution (0.9%) at a depth of 4.4 cm in porcine fat tissue was successfully detected in TA images. The PA axial, lateral, and elevational resolutions were 640 μm, 720 μm, and 3.5 mm, respectively, suitable for breast cancer imaging. A PA noise-equivalent sensitivity to methylene blue solution of 260 nM was achieved in chicken tissue at a depth of 3.4 cm.

Ki-67 expression in oral lichen planus

PURPOSE

The monoclonal antibody Ki-67 detects a nuclear antigen that is present only in proliferating cells. This is of particular interest for the analysis of the proliferation rates of malignant tumors. The aim of this study was to investigate the malignant potential of oral lichen planus (OLP) on the basis of expression of Ki-67 in healthy individuals (HI), patients with OLP and patients with squamous cell carcinoma (SCC), and to see for any potential interdependence between Ki-67 expression and different clinical and histopathological parameters in OLP.

METHODS

Immunohistochemistry for Ki-67 was carried out using an avidin-biotin peroxidase complex method.

RESULTS

Ki-67 was more expressed in keratinocytes and lymphocytes of OLP patients compared with HI, but less compared with patients with SCC. Keratinocytes and lymphocytes stained with Ki-67 in OLP patients were significantly higher in males, and in OLP specimens showed less developed civatte bodies (CB) and thickening of the basal membrane (TBM).

CONCLUSION

Ki-67 may not serve as prognostic biomarker in oral cancer development from the initially diagnosed OLP, but it could help selecting patients with higher need of follow up for prevention of malignancy.

Performance benchmarks of an array-based hand-held photoacoustic probe adapted from a clinical ultrasound system for non-invasive sentinel lymph node imaging

Clinical translation of photoacoustic (PA) imaging can be facilitated by integration with commercial ultrasound (US) scanners to enable dual-modality imaging. An array-based US scanner was modified for hand-held PA imaging. The performance was benchmarked in terms of signal-to-noise ratio (SNR), axial spatial resolution and sensitivity. PA images of a tube, filled with methylene blue (MB; approx. 30 mM) and placed at various depths in chicken tissue, were acquired. A 5 cm penetration depth was achieved with an 18.6 dB SNR using a laser fluence of 3 mJ cm(-2), only one-seventh of the safety limit (20 mJ cm(-2)). An axial resolution of approximately 400 μm was maintained at all imaging depths. The PA sensitivity to MB placed 2.3 cm deep in chicken tissue was less than 100 μM. Further, after intradermal injection of MB (approx. 30 mM), a rat sentinel lymph node was clearly identified in vivo, beneath a 3.8 cm thick layer of chicken breast. The accumulated concentration of MB in the node was estimated to be approximately 7 mM. The noise-equivalent sensitivities (approx. 2 cm depth) were 17 and 85 μM, ex vivo and in vivo, respectively. These results support the use of this PA system for non-invasive mapping and image-guided needle biopsy of sentinel nodes in breast cancer patients.

Deeply penetrating in vivo photoacoustic imaging using a clinical ultrasound array system

Using a hand-held photoacoustic probe integrated with a clinical ultrasound array system, we successfully imaged objects deeply positioned in biological tissues. The optical contrasts were enhanced by methylene blue with a concentration of ~30 mM. The penetration depth reached ~5.2 cm in chicken breast tissue by using 650-nm wavelength, which is ~4.7 times the 1/e optical penetration depth. This imaging depth was achieved using a laser fluence on the tissue surface of only 3 mJ/cm(2), which is 1/7 of the American National Standards Institute (ANSI) safety limit (20 mJ/cm(2)). The noise equivalent sensitivity at this depth was ~11 mM. Further, after intradermal injection of methylene blue in a rat, a sentinel lymph node was easily detected in vivo, beneath a 2-cm thick layer of chicken breast. Also, blood located 3.5 cm deep in the rat was clearly imaged with intrinsic contrast. We have photoacoustically guided insertion of a needle into a rat sentinel lymph node with accumulated methylene blue. These results highlight the clinical potential of photoacoustic image-guided identification and needle biopsy of sentinel lymph nodes for axillary staging in breast cancer patients.

Sentinel lymph nodes in the rat: noninvasive photoacoustic and US imaging with a clinical US system

PURPOSE

To evaluate in vivo sentinel lymph node (SLN) mapping by using photoacoustic and ultrasonographic (US) imaging with a modified clinical US imaging system.

MATERIALS AND METHODS

Animal protocols were approved by the Animal Studies Committee. Methylene blue dye accumulation in axillary lymph nodes of seven healthy Sprague-Dawley rats was imaged by using a photoacoustic imaging system adapted from a clinical US imaging system. To investigate clinical translation, the imaging depth was extended up to 2.5 cm by adding chicken or turkey breast on top of the rat skin surface. Three-dimensional photoacoustic images were acquired by mechanically scanning the US transducer and light delivery fiber bundle along the elevational direction.

RESULTS

Photoacoustic images of rat SLNs clearly help visualization of methylene blue accumulation, whereas coregistered photoacoustic/US images depict lymph node positions relative to surrounding anatomy. Twenty minutes following methylene blue injection, photoacoustic signals from SLN regions increased nearly 33-fold from baseline signals in preinjection images, and mean contrast between SLNs and background tissue was 76.0 +/- 23.7 (standard deviation). Methylene blue accumulation in SLNs was confirmed photoacoustically by using the optical absorption spectrum of the dye. Three-dimensional photoacoustic images demonstrate dynamic accumulation of methylene blue in SLNs after traveling through lymph vessels.

CONCLUSION

In vivo photoacoustic and US mapping of SLNs was successfully demonstrated with a modified clinical US scanner. These results raise confidence that photoacoustic and US imaging can be used clinically for accurate, noninvasive imaging of SLNs for axillary lymph node staging in breast cancer patients.

Handheld array-based photoacoustic probe for guiding needle biopsy of sentinel lymph nodes

By modifying a clinical ultrasound array system, we develop a novel handheld photoacoustic probe for image-guided needle biopsy. The integration of optical fiber bundles for pulsed laser light delivery enables photoacoustic image-guided insertion of a needle into rat axillary lymph nodes with accumulated indocyanine green (ICG). Strong photoacoustic contrast of the needle is achieved. After subcutaneous injection of the dye in the left forepaw, sentinel lymph nodes are easily detected, in vivo and in real time, beneath 2-cm-thick chicken breast overlaying the axillary region. ICG uptake in axillary lymph nodes is confirmed with fluorescence imaging both in vivo and ex vivo. These results demonstrate the clinical potential of this handheld photoacoustic system for facile identification and needle biopsy of sentinel lymph nodes for cancer staging and metastasis detection in humans.

Oral status in patients receiving 5-fluorouracil for colorectal cancer

PURPOSE

Oral complications are frequent and troublesome symptoms for those undergoing chemotherapy for cancer. Several antineoplastic agents are proved to have stomatotoxic potential, among them 5-fluorouracil (5-FU). The aim of the present study was to evaluate the oral status and patient experiences during chemotherapy with 5-FU for colorectal cancer.

METHODS

Twenty-eight patients treated with 5-day 5-FU plus leucovorin entered this study. Positive data about oral symptoms were taken by anamnesis. Mucositis severity index, gingival index, plaque index, probing pocket depth and bleeding on probing have been used to assess oral mucosa and periodontal status of the patients. Patients were examined prior to chemotherapy and 14 days after the start of the chemotherapy cycle.

RESULTS

Mild to moderate subjective complaints concerning oral cavity were reported by 17.9% of patients before and 39.2% of patients after chemotherapy. Clinical examination revealed oral mucosa damage in 10.7% and 35.7% of patients, with mean mucositis score of 0.14 and 0.54 before and after chemotherapy, respectively. Although mean values of all periodontal indices were elevated after chemotherapy, only increase in gingival index was statistically significant (p=0.035). Mucositis was significantly correlated with oral pain (p=0.00), xerostomia (p=0.00), and plaque index (p=0.077), while the correlation between mucositis and the rest of the examined parameters was not significant.

CONCLUSION

Oral complications were not highly expressed in this study. Although 5-FU is considered to exert significant stomatotoxic effect, severe mucositis was far less common in this study compared to studies reported elsewhere.

Bcl-2 expression and its possible influence on malignant transformation of oral lichen planus

PURPOSE

The aim of this study was to investigate the malignant potential of oral lichen planus (OLP) on the basis of the expression of the Bcl-2 marker in healthy individuals (H), patients with OLP and patients with squamous cell carcinoma (SCC), and to establish potential interdependence between expression of Bcl-2 and the different clinical and histopathological parameters in H, OLP, and SCC.

METHODS

Immunohistochemistry for Bcl-2 was carried out using an avidin-biotin peroxidase complex method. Tissue sections were treated with mouse monoclonal antibody against Bcl-2 (124, DAKO A/S, Denmark; dilution 1/100). Immunohistochemical parameters measured included total tissue area, total stained area and intensity of stain.

RESULTS

Keratinocytes were not Bcl-2 positive in H and were sparsely positive in OLP. The number of lymphocytes stained with Bcl-2 was significantly lower in H as compared to patients with SCC and OLP. Bcl-2 staining was weak to moderate in OLP, and moderate to intense in SCC. Bcl-2-positive lymphocytes were more expressed in older OLP patients (>55 years), and in OLP specimens with orthokeratinized epithelium, less developed acanthosis and highest grade of lymphocyte expression.

CONCLUSION

Bcl-2 may not serve as a prognostic biomarker in oral cancer development from OLP, but it could help in selecting patients with higher need of follow up to prevent malignancy.

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: management strategies and economic impact

PURPOSE

This systematic review aimed to assess the literature for management strategies and economic impact of salivary gland hypofunction and xerostomia induced by cancer therapies and to determine the quality of evidence-based management recommendations.

METHODS

The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. For each article, two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results, and conclusions.

RESULTS

Seventy-two interventional studies met the inclusion criteria. In addition, 49 intensity-modulated radiation therapy (IMRT) studies were included as a management strategy aiming for less salivary gland damage. Management guideline recommendations were drawn up for IMRT, amifostine, muscarinic agonist stimulation, oral mucosal lubricants, acupuncture, and submandibular gland transfer.

CONCLUSIONS

There is evidence that salivary gland hypofunction and xerostomia induced by cancer therapies can be prevented or symptoms be minimized to some degree, depending on the type of cancer treatment. Management guideline recommendations are provided for IMRT, amifostine, muscarinic agonist stimulation, oral mucosal lubricants, acupuncture, and submandibular gland transfer. Fields of sparse literature identified included effects of gustatory and masticatory stimulation, specific oral mucosal lubricant formulas, submandibular gland transfer, acupuncture, hyperbaric oxygen treatment, management strategies in pediatric cancer populations, and the economic consequences of salivary gland hypofunction and xerostomia.

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: prevalence, severity and impact on quality of life

PURPOSE

This systematic review aimed to assess the literature for prevalence, severity, and impact on quality of life of salivary gland hypofunction and xerostomia induced by cancer therapies.

METHODS

The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. Two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results and conclusions for each article.

RESULTS

The inclusion criteria were met by 184 articles covering salivary gland hypofunction and xerostomia induced by conventional, 3D conformal radiotherapy or intensity-modulated radiotherapy in head and neck cancer patients, cancer chemotherapy, total body irradiation/hematopoietic stem cell transplantation, radioactive iodine treatment, and immunotherapy.

CONCLUSIONS

Salivary gland hypofunction and xerostomia are induced by radiotherapy in the head and neck region depending on the cumulative radiation dose to the gland tissue. Treatment focus should be on optimized/new approaches to further reduce the dose to the parotids, and particularly submandibular and minor salivary glands, as these glands are major contributors to moistening of oral tissues. Other cancer treatments also induce salivary gland hypofunction, although to a lesser severity, and in the case of chemotherapy and immunotherapy, the adverse effect is temporary. Fields of sparse literature included pediatric cancer populations, cancer chemotherapy, radioactive iodine treatment, total body irradiation/hematopoietic stem cell transplantation, and immunotherapy.

Expression of Fas/FasL in patients with oral lichen planus

PURPOSE

To investigate the malignant potential of oral lichen planus (OLP) on the basis of expression of the Fas/FasL markers in healthy individuals (H), OLP patients and patients with squamous cell carcinoma (SCC).

PATIENTS AND METHODS

40 patients with OLP and two control groups were included in this research (H and patients with SCC). Immunohistochemistry for Fas and FasL was carried out using an avidin-biotin peroxidase complex method.

RESULTS

Only a low percentage of infiltrating lymphocytes and no keratinocytes were Fas-positive in OLP specimens. The highest percentage of Fas-staining keratinocytes in our survey was identified mostly in H and patients with well-differentiated SCC. In most cases of SCC, OLP and H a high percentage of keratinocytes and lymphocytes were FasL-positive. FasL expression was negatively correlated with the degree of cell differentiation and apoptosis. Taking into consideration that all carcinomas in this survey were highly differentiated, it is not surprising that no statistically significant differences in FasL expression between H, OLP and SCC specimens were detected.

CONCLUSION

Downregulation of Fas expression in keratinocytes and lymphocytes of OLP specimens, together with upregulation of FasL, may serve as initial prognostic biomarker in oral cancer development.

Humoral immunity to cow's milk proteins and gliadin within the etiology of recurrent aphthous ulcers?

OBJECTIVES

The goal of this study was to determine the incidence of serum antibodies to gliadin and to cow's milk proteins (CMP) using ELISA test, within patients who have recurrent aphthous ulcers (RAU).

SUBJECTS AND METHODS

Fifty patients with recurrent aphthous ulcers and fifty healthy people were included in this research. Levels of serum IgA and IgG antibodies to gliadin and IgA, IgG and IgE to CMP were determined using ELISA.

RESULTS

The levels of serum antigliadin IgA and IgG antibodies were not significantly higher in patients with RAU in comparison with the controls (P = 0.937 and P = 0.1854 respectively). The levels of serum anti-CMP IgA, IgG and IgE antibodies were significantly higher in patients with RAU in comparison with the controls (P < 0.005, P < 0.002 and P < 0.001 respectively). In general, the increased humoral (IgA or IgG) immunoreactivity to CMP was found in 32 of 50 patients, while 17 of them showed the increased levels of both IgA and IgG immunoreactivity to CMP. At the same time, 16 out of 50 patients had IgA, IgG and IgE immunoreactivity to CMP.

CONCLUSION

These results indicate the strong association between high levels of serum anti-CMP IgA, IgG and IgE antibodies and clinical manifestations of recurrent aphthous ulcers.

Acoustic fingerprints of dye-labeled protein submicrosphere photoacoustic contrast agents

Dye-labeled protein microspheres, submicron in size and capable of producing thermoelastically generated ultrasound in response to laser stimulation, are presented as contrast agents for photoacoustic imaging. Incident laser energy absorbed by fluorescein isothiocyanate (FITC)-labeled elastin submicrospheres results in thermoelastically generated sound production. Plotted A-line graphs reveal a distinctive morphology and a greater than two orders of magnitude increase in signal amplitude subsequent to converting FITC elastin into submicrospheres (despite a four orders of magnitude decrease in concentration). Evidence of nonlinearity and enhancement of ultrasound backscatter indicate a potential use in contrast-enhanced harmonic imaging. Photoacoustic and ultrasound imaging of FITC-elastin submicrospheres in a water-filled phantom vessel shows enhanced contrast at low concentration and clear delineation of the phantom vessel wall.

High-dose calcitriol therapy and progression of cardiac vascular calcifications

BACKGROUND

Dialysis patients show a very high prevalence of cardiovascular complications, affected as they are with abnormal and accelerated vascular calcifications and, eventually, calcium and phosphorous metabolism disorders. Multislice computed tomography (MSCT) provides a reproducible, high-resolution imaging of calcium contained in cardiac arteries, measured by Agatston score. The aim of the present study was to evaluate the influence of high-dose and low-dose calcitriol therapy on the progression of cardiac vascular calcifications in dialyzed patients.

METHODS

We enrolled 36 dialyzed patients in a prospective study, including an interventional period of 12 months and a follow-up period of 12 months. Eighteen protocol patients received intravenous pulses of high-doses calcitriol at the end of dialytic treatment and sevelamer hydrochloride therapy. Control patients received low-dose calcitriol and sevelamer hydrochloride as well. Two MSCT scans were performed: 1 at the start of the study and 1 at the end of follow-up, and Agatston score was calculated at both examinations.

RESULTS

At first examination, protocol patients showed almost the same level of cardiac vascular calcification as control patients. At the second MSCT, statistically significantly higher values of Agatston score were recorded for all patients. Indeed, patients who showed higher baseline values developed worse calcifications as recorded at the end of follow-up, both in the protocol and control group.

CONCLUSIONS

Our data show that baseline level is strongly predictive of vascular calcification progression, and, moreover, there is no association between calcitriol administered doses and the progression of cardiac vascular calcification.

Cardiac calcifications in hemodialysis patients assessed with spiral computed tomography

AIM

Cardiac disease is a major cause of mortality in uremic patients. The aim of this paper was to evaluate cardiac calcium content in uremic patients with multislice computed tomography (MSCT).

METHODS

The study has been carried out on 120 uremic and 28 nonuremic patients affected by cardiovascular disease. Serum calcium, phosphorus, calcium-phosphate product, intact PTH were assayed. Several lipidic and nutritional parameters were measured. Calcification values obtained with the MSCT were reported in terms of Agatson scores.

RESULTS

We found that the average score values in cohort on uremic was 10 times higher than in nonuremic patients (score values 3.389 vs 328). Cardiac calcification score was found to be correlated significantly to age (P=0.006), HD age (P=0.010), serum calcium (P=0.006), iPTH (P=0.004). Multiregression analysis (MRA) with the cardiac score as dependent variable selected the following variables (R(2) 0.612): age (P=0.002), HD age (P=0.010), serum cholesterol (P<0.000), triglycerides (P=0.001) and inversely HDL cholesterol (P=0.001) and non-HDL cholesterol (P=0.001) as predictive variables for cardiac score. By comparing patients with scores lower and higher than 400, the group with score <400 showed a significantly lower age (P=0.0001), HD vintage (P=0.01) and a significantly higher serum cholesterol (P=0.009), HDL cholesterol (P=0.05) and non-HDL cholesterol (P=0.05).

CONCLUSIONS

The MSCT could help in identifying and stratifying high-risk patients to implement preventive strategies. The control of mineral metabolism and of lipid levels is important in prevention of arterial calcification in uremic patients.

All-optical switching and multifrequency generation in a dual-core photonic crystal fiber

We demonstrate all-optical switching at 1550 nm between two weakly coupled cores in a photonic crystal fiber for intensities up to 0.5 TW/cm2. Spectrum analysis at higher intensities reveals that the output was dominated by continuum generation primarily towards shorter wavelengths.

Quadratic soliton collisions

The details of two soliton collision processes were investigated in detail in a 1 cm long periodically poled KTP crystal for the case when the solitons were excited by inputting only the fundamental beam. The effects on the collision outcomes of the distance of the collision into the sample, collision angle and phase mismatch were measured for different relative phases between the input beams. At small angles (around 0.4 degrees ) fusion, repulsion and energy transfer processes were observed, while at the collision angles approaching 3.2 degrees the two output soliton beams were essentially unaffected by the interaction. The phase mismatch was varied from 3.5 to -1.5pi for the 0.4 degrees collision angle case. The output solitons separation at pi input phase difference showed strongly asymmetric behavior with phase mismatch. In general, the measurements indicate a decrease in the interaction strength with increasing phase mismatch. All collision processes were performed in the vicinity of a non-critical phase matching.

Quadratic soliton self-reflection at a quadratically nonlinear interface

The reflection of bulk quadratic solutions incident onto a quadratically nonlinear interface in periodically poled potassium titanyl phosphate was observed. The interface consisted of the boundary between two quasi-phase-matched regions displaced from each other by a half-period. At high intensities and small angles of incidence the soliton is reflected.

Complex soliton-like pattern generation in Potassium Niobate due to noisy, high intensity, input beams

We report the generation of complex soliton-like patterns in noncritically-phase-matched potassium niobate which occur in random spatial patterns from shot-to-shot. Up to five spots have been generated at input intensities of 10's GW/cm2, many times the single soliton threshold. The mechanism which leads to the symmetry breaking required for the complex patterns is interpreted to be random noise imprinted on the input light.

Weak beam control of multiple quadratic soliton generation

Theoretical predictions and experimental observations show that a weak harmonic seed beam can control the process of generating multiple quadratic solitons in periodically poled KTiOPO4 by inputting only a fundamental beam. This all-optical switching does not depend on the relative phase of the input beams, an unusual property for such coherent solitons.

Tellurite glasses with peak absolute Raman gain coefficients up to 30 times that of fused silica

An experimental system has been assembled to measure the absolute values of the Raman gain spectrum for millimeter-thick glass samples. Results are reported for two new oxide glasses with Raman gain coefficients as much as 30 times larger than that of fused silica and more than twice its spectral coverage.

Birth of solitons in quadratic spatial soliton collisions

We demonstrate experimentally and theoretically the creation of a third soliton in two soliton collision processes in type I noncritically phase-matched KNbO3. The output pattern in the collision process is phase dependent, but the total energy and the relative ratio of the fundamental to the second harmonic in each soliton remain essentially unchanged to within experimental accuracy.

Properties of quadratic multi-soliton generation near phase-match in periodically poled potassium titanyl phosphate

The properties of the multi-quadratic-soliton generation process have been investigated both theoretically and experimentally near and on phase-match in non-critically-phase-matched, periodically poled, potassium titanyl phosphate (PPKTP). It was found that multi-soliton generation occurs primarily due to asymmetry in the input beam and at phase-matching. The number of solitons generated depended on the input intensity in a non-trivial way.

Quadratic spatial solitons in periodically poled KTiOPO4

The evolution of fundamental beams into quadratic spatial solitons was investigated in a periodically poled bulk KTiOPO4 crystal near and at phase matching. Various soliton properties, such as trapping efficiency as a function of phase mismatch, poling-induced walk-off, and the effects of pulse width, beam width, and input beam quality, were measured. Effects attributed to the presence of cubic nonlinearities were also observed.

Observation of multiple soliton generation mediated by amplification of asymmetries

We report the experimental observation of the formation of multiple optical quadratic solitons in a process mediated by the amplification of minute asymmetries in the diffraction properties of the input light. Experiments were conducted in phase-matched second-harmonic generation in a bulk crystal of periodically poled potassium titanyl phosphate pumped at 1064 nm. The different mechanisms that influence the process were investigated numerically, and the pulsed nature of the pump light was found to play a key role in the observed light distributions.

Effects of anisotropic diffraction on quadratic multisoliton excitation in noncritically p hase-matched crystals

The generation of multiple quadratic spatial solitons aligned approximately along a crystal axis in a biaxial noncritically phase-matched crystal is shown theoretically and experimentally to be the consequence of anisotropic diffraction.

Two-dimensional type I quadratic spatial solitons in KNbO(3) near noncritical phase matching

Experiments on the properties of quadratic, two-dimensional spatial soliton properties in KNbO(3) near and at noncritical phase matching (NCPM) are reported. The NCPM geometry leads to unique features such as a large angular bandwidth for soliton generation, weak dependence of soliton composition on intensity and incidence angle, and unique multisoliton-generation properties.

Spatial modulation instability in a Kerr slab waveguide

We report the observation of noise-initiated modulational instability in AlGaAs slab waveguides at 1.55 microm . Experiments were performed with the local, ultrafast Kerr nonlinearity at half the bandgap. The agreement between experiment and theory for the periodicity versus intensity was good.

A beta zero-thalassaemia due to a 1605 bp deletion of the 5' beta-globin gene region

We studied a heterozygous beta zero-thalassaemia patient from Croatia with an unusually high Hb A2 level of 7.6% and an elevated Hb F level of 5.8%. The same condition was found in his father (Hb A2 8.2%; Hb F 8.5%). Gene mapping and direct sequencing analyses revealed a new deletion of 1605 bp in the 5' beta-globin gene region between positions -984/5 and +620/1. This deletion has not been observed among more than 500 beta-thalassaemia chromosomes from the Balkan countries studied in our laboratory.

A new mutation in the beta-globin gene (IVS II-850 G-C) found in a Yugoslavian beta-thalassemia heterozygote

BACKGROUND

The recent development of laboratory techniques that can rapidly characterize the molecular defects of beta-thalassemia has resulted in the discovery of more than 100 different point mutations in the beta-globin gene. These mutations are population specific. About 20 of them account for over 90% of beta-thal genes in the world. The other mutations are usually found in single families. In this paper we describe a case with a novel mutation at position IVS II-850 (G-C) as a cause of beta-thalassemia.

METHODS

Direct sequencing of PCR amplified DNA was used for the detection of the mutation. ASO probes were synthesized for dot-blot hybridization. Expression of the mutated allele was evaluated through Northern blot and RNA-PCR analyses.

RESULTS

This mutation was found in four members of a family, who exhibited severe microcytosis and hypochromic anemia, with an average alpha/beta ratio of 2.0. The sequencing of PCR amplified DNA showed a G-C mutation at position IVS II-850 of the beta-globin gene. Dot blot analyses confirmed the presence of this substitution in all four carriers. Northern blot and RNA-PCR analyses did not reveal any abnormally spliced mRNA species.

DISCUSSION

The G-C substitution at position IVS II-850 is the third mutation in the invariant AG dinucleotide of the acceptor splice site of the second intron of the beta-globin gene. It abolishes normal splicing, which leads to abnormally processed mRNA. It is a relatively rare mutation since it was not detected among the uncharacterized beta-thal chromosomes from Yugoslavia.

A C----G mutation at nt position 6 3' to the terminating codon may be the cause of a silent beta-thalassemia

We describe the hematological and clinical data for a young Greek patient with beta-thalassemia intermedia and for several members of her family. The patient had inherited the common IVS-I-1 (G----A) mutation from her mother, while the second beta-globin gene had a C----G mutation at position 6 3' to the terminating codon (term. + 6). Her father and three additional relatives with a heterozygosity for this newly discovered mutation had no hematological abnormalities, normal Hb A2 values, and a nearly normal in vitro chain synthesis ratio. Analyses of nearly 500 additional beta-thalassemia and normal chromosomes failed to detect this mutation which eliminates it as a common polymorphism. Although our findings may indicate a rare polymorphism, the probability that it represents the cause of diminished beta chain synthesis is very high indeed. We suggest that the C----G mutation in this untranslated region of the beta-globin gene causes a slight decrease in the stability of the mRNA which becomes clinically important only in situations when beta chain synthesis in trans is eliminated.

Two novel polyadenylation mutations leading to beta(+)-thalassemia

In an ongoing effort to identify point mutations causing beta-thalassaemia, we have found two previously unreported mutations which are located in the Poly A site of the beta-globin gene. The screening programme used amplified DNA and dot-blot hybridization with several 32P-labelled oligonucleotide probes. DNA samples which remained unidentified by this methodology were subjected to sequencing with 32P-labelled primers and modified T7 DNA polymerase. The newly discovered mutations were confirmed by the dot-blot hybridization technique. One type concerned an AATAAA----AATGAA mutation in the polyadenylation site and was found in one family from Yugoslavia (including one patient with the C----T mutation at codon 29 in trans), one from Bulgaria (the patient had the G----A mutation at IVS-I-110 in trans), and one from Greece (this patient had the C----G mutation at IVS-II-745 in trans). Haematological data for three simple heterozygotes suggested a rather mild beta(+)-thalassemia. The second type involved an AATAAA----AATAGA mutation and was found in one family from Malaysia. The propositus had the beta E mutation on the other chromosome, was originally diagnosed as mild Hb E-beta(+)-thalassaemia, and had Hb A and Hb E percentages which were nearly the same.

Beta-thalassemia in Yugoslavia

This study concerned the evaluation of beta-thalassemia alleles in nearly 50 patients with beta-thalassemia major and in 130 -thalassemia heterozygotes using gene amplification and dot-blot hybridization with synthetic probes. Fourteen different mutations were observed; of these, three (IVS-I-110; IVS-I-6; IVS-I-1) account for some 75% of all beta-thalassemia alleles. Newly discovered variants, i.e. T----C in the initiation codon and AATAAA----AATGAA in the poly A site were observed in a few patients. The poly A mutation with classical beta-thalassemia alleles result in thalassemia intermedia. Hb Lepore is a rather common abnormality and combinations of this variant with beta-thalassemia often result in severe disease; a search for beta-thalassemia mutations among patients affected with this disease should include an analysis to detect this hemoglobin abnormality.

An initiation codon mutation as a cause of a beta-thalassemia

During the course of a screening program for beta-thalassemia mutations among beta-thalassemia heterozygotes in Yugoslavia we observed a mutation (ATG----ACG) in the initiation codon of the beta-globin gene which has not been described before. The abnormality was initially detected through mapping of the beta-globin gene by Southern blot analysis using the restriction enzyme Nco I. The loss of the Nco I site resulted in the presence of an 8.3 kb band in addition to the normal 5.2 kb band. The mutation was identified by sequence analysis of amplified DNA and by dot-blot analysis of this DNA with a 32P-labeled oligonucleotide probe. An additional polymorphism (CAC----CAT) was present at codon 2 on the same chromosome; this mutation was detected by Orkin et al in 1982 (1). Hematological and in vitro chain synthesis data suggest that the beta-thalassemia is of the beta zero type.

Combined procedure of open reduction and shortening of the femur in treatment of congenital dislocation of the hips in older children

A one-stage, combined operative procedure for reduction of congenitally dislocated hips in older children consists of shortening of the femur; open reduction by an inferior approach to the joint; reconstruction of the acetabular roof; correction of anteversion of both the femoral neck and the neck-shaft angle; anterior transposition of the iliopsoas muscle. On 60 hips operated in children, ages 5 to 15 with a follow-up period, ranging from 5 to 9 years, the results were found to be excellent in 3 per cent, good in 60 per cent, fair in 30 per cent, and poor in 7 per cent. The procedure is indicated in children up to the time of early puberty. The primary indication is high bilateral dislocation. In unilateral dislocations some residual leg-length discrepancy frequently occurs. This procedure should be done only by orthopedic surgeons who have special training and experience in the treatment of congenital dislocation of the hip.