Toward low-loss mid-infrared Ga2O3-BaO-GeO2 optical fibers

The development of efficient and compact photonic systems in support of mid-infrared integrated optics is currently facing several challenges. To date, most mid-infrared glass-based devices are employing fluoride or chalcogenide glasses (FCGs). Although the commercialization of FCGs-based optical devices has rapidly grown during the last decade, their development is rather cumbersome due to either poor crystallization and hygroscopicity resilience or poor mechanical-thermal properties of the FCGs. To overcome these issues, the parallel development of heavy-metal oxide optical fiber from the barium-germanium-gallium oxide vitreous system (BGG) has revealed a promising alternative. However, over 30 years of fiber fabrication optimization, the final missing step of drawing BGG fibers with acceptable losses for meters-long active and passive optical devices had not yet been reached. In this article, we first identify the three most important factors that prevent the fabrication of low-loss BGG fibers i.e., surface quality, volumic striae and glass thermal-darkening. Each of the three factors is then addressed in setting up a protocol enabling the fabrication of low-loss optical fibers from gallium-rich BGG glass compositions. Accordingly, to the best of our knowledge, we report the lowest losses ever measured in a BGG glass fiber i.e., down to 200 dB km-1 at 1350 nm.

Elimination Pathway of Hematoporphyrin from Normal and Tumor-Bearing Rats

Hematoporphyrin orally administered to rats largely precipitates in the stomach thus reaching the various tissues at a very slow rate. Whatever the administration pathway (oral, i.p., i.V.), hematoporphyrin is eliminated in the feces with no apparent chemical modification; the elimination is slower from rats affected by ascites hepatoma than from normal rats owing to the high affinity of tumor cells for the porphyrin.

Time Dependence of Hematoporphyrin Distribution in Selected Tissues of Normal Rats and in Ascites Hepatoma

The distribution of hematoporphyrin was determined in normal rats and in rats bearing ascites hepatoma as a function of time after i.p. injection of 10-20 mg/kg of dye. In both cases, hematoporphyrin displayed a high affinity for the tumor cells. At 20 mg/kg, the maximum difference between the amount of hematoporphyrin accumulated in the tumor and in the liver was obtained at 12 h after injection (tumor/liver ratio = 28). Our results suggest that hematoporphyrin is almost exclusively metabolized in the liver and excreted via the biliary tract, whereas only minor amounts are metabolized in the tumor cells. Moreover, the binding between the porphyrin and tumor cells is competitive with serum protein binding.

Ultrarapid high-dose course of prophylactic cranial irradiation in small-cell lung cancer: evaluation of late neurologic morbidity in 16 long-term survivors

Despite the reduction in the incidence of brain metastases following prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC), the use of this modality is still controversial due to the lack of improvement in survival and the appearance of neurotoxicity in long-term survivors. Moreover, the optimum dose, fraction size, and timing are not known. From 1980 to 1988, 70 patients with limited stage SCLC underwent PCI after or during multimodality treatment of their primary tumor. Most of these patients (75.7%) received an unconventional ultrarapid high-dose course of 17 Gy in two fractions over 3 days. Long-term (range 60-138 months) survivors (n = 16) were invited to have a complete neurological evaluation including computed cranial tomography (CCT), 99mTc-HMPAO single photon emission computerized tomography (SPECT) scan, electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychometry. Delayed neurologic complications or psychometric impairment was observed in 46% of patients. One or more abnormalities were detected by CCT in all patients, and the presence of neurologic complications seemed to correlate with periventricular and subcortical white matter changes. A strong correlation was found between CCT and SPECT periventricular white matter changes. Although the incidence of late neurologic toxicity following this rapid course of irradiation was high, clinical findings were less severe than expected, and all the patients were capable of self-care.

Photodynamic therapy in gynaecological neoplastic diseases

Since 1982, our department has used photodynamic therapy (PDT) in the treatment of loco-regional recurrences of gynaecological cancers. We have treated 26 patients in this time. In the majority of cases the site of vaginal recurrences was the vaginal vault. The light sources were an Argon-dye laser (Meditec) and, in some cases, a CO2 laser. The light dose ranged between 60 and 500 J cm-2. The photosensitizing drug used was Hematoporphyrin (HP) (Monico Farmaceutici) at the dose of 5 mg kg-1 body weight. Patients were evaluated 45 days after the treatment with a gynaecological examination and after 75-90 days with a vaginal smear. The results were divided into 2 groups: objective and symptomatic. The symptomatic response concerned only the patients treated with a palliative aim and, in this case, a complete response (CR) was a complete absence of symptoms at least for 60 days. In this group the complete response rate was 66%. In the curative group, the complete response was a cytological and/or histological absence of lesions. In this group we had 12 CR (70.58%). The survival rate was also evaluated. A significant review of the photodynamic therapy in gynaecological neoplasms has also been done.

[Analysis of recurrences following conservative treatment of breast carcinoma]

In the conservative treatment of early breast cancer, great attention must be paid to define the prognostic factors correlated with the local recurrence rate. The goal is to customize surgery, radiotherapy and chemotherapy to the risk predicted in every single patient. To investigate the impact of some prognostic factors in a group of patients treated with homogeneous treatment schedules, 251 women with UICC stage I or II breast cancer were examined in the Padua Radiotherapy Department from 1988 to 1990. All patients underwent conservative surgery consisting in quadrantectomy, axillary node dissection and radiotherapy. During a median follow-up period of 49.2 months, 12 patients presented a breast relapse (4.8%). In 4 patients the relapse occurred in the same quandrant as the primary lesion, whereas a different quadrant was involved in the other 8 patients. The relapse rate in women under 60 was 5% and 4.7% in older patients, with p = 0.73. In pT1 patients, the relapse rate was 4.5% and in pT2 patients it was 7.9% (p = 0.37). No significant difference was observed between pN- and pN+ patients (4.5% vs. 6.25%, p = 0.37). In our series, none of the studied factors significantly influenced breast relapse rates. The number of patients may be too little relative to the low rate of relapses. However, an unfavorable trend was observed in the patients under 60, in pT2 or pN+ patients, or in the patients with positive or unknown surgical margins.

Gynecologic cancer recurrences and photodynamic therapy: our experience

The incidence of locoregional recurrences of gynecological tumors is still a major problem. Many authors suggest that it is the major cause of death in patients affected by cervical-endometrial cancers. The results achieved by retreating these patients with conventional therapies are still unsatisfactory. Since 1982, in our department, we have been using photodynamic therapy (PDT) for treatment of locoregional recurrences in gynecological cancers. We have treated 26 patients. In the majority of the cases, vaginal recurrences were on the vaginal vault. Out of 26 cancers, 17 were epidermoid cancers. Lasers used were the argon dye laser (Meditec) and, in some cases, the CO2 laser. Light dose ranged between 60 and 500 J/cm2. The photosensitizing drug used was hematoporphyrin (HP) (Monico Farmaceutici, Venezia, Italy) at a dose of 5 mg/kg body weight. Patients were evaluated 45 days after treatment with gynecological examination and again after 75-90 days with a vaginal smear. Results were divided into 2 groups: objective and symptomatic. The symptomatic response concerned only patients treated with a palliative aim and, in this case, a complete response (CR) was a complete absence of symptoms for at least 60 days. In this group the complete response rate was 66.6%. In the curative group, the complete response was a cytological and/or histological absence of lesion. In this group we had 12 CR (70.58%). The survival rate of patients treated only with PDT ranged between 3 and 92 months (mean 50.7 months). No major acute or side effects were recorded.

[Neoplasms of the gallbladder and the extrahepatic bile ducts: radio-chemotherapeutic combined treatment. Results in 18 treated cases]

According to current literature, the main cause of death in patients with gallbladder (GB) and extrahepatic biliary ducts (EHBD) neoplasms is related to local and locoregional tumor spread rather than to distant metastases. Surgery, even when radical, is followed by a high number of relapses. That is why postoperative radiation therapy (RT) is usually combined with surgery. Alone, however, RT is not effective enough to markedly improve loco-regional control, considering that the adjacent organs would be damaged by higher doses. Referring to experimental studies published in the 1960s and relative to the biological effect of ionizing radiation with 5-Fluorouracil (5-FU) in slowing the pace of tumor growth, the Department of Radiotherapy, together with the Department of Medical Oncology in Padua General Hospital, began administering a combined surgical-chemo-radiotherapeutic protocol in January 1982, to January 1989. The protocol included 5-FU administration both 3 days before and during RT, after a surgical intervention as radical as possible. Eighteen patients were given this treatment. By the end of December 1989, 7 patients were alive--6 of them disease-free with a 26-month mean survival. Eleven patients died--7 due to local/loco-regional relapse, 1 from a distant metastasis, 1 from gastric hemorrhage, with no disease, and 2 from unknown causes. Overall mean survival in the two groups was 16 months. The combined treatment proved to be tolerable and feasible, even though severe complications were observed in 2 patients, 1 case of toxic death (gastric hemorrhage) and another with complete duodenal stenosis which required further surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Oesophageal cancer treated by photodynamic therapy alone or followed by radiation therapy

Photodynamic therapy (PDT) with porphyrins and red light is receiving increasing attention in the management of malignant tumours. At present PDT is primarily indicated for the treatment of superficial or early-stage lesions. At the Department of Radiotherapy and the First Institute of Surgery in Padova (Italy) more than 150 cases of tumours of different types have been treated using this technique. This paper briefly describes 21 cases of superficial oesophageal cancer. A complete response was observed in 11 of 21 cases. Radiation therapy appeared to be very effective as a salvage treatment of non-response patients.

[Cyclophosphamide and total lymph node irradiation as conditioning for bone marrow transplant in severe aplastic anemia]

Personal experience is outlined with a preparative regimen consisting of total nodal irradiation (TNI) and cyclophosphamide in patients with severe aplastic anemia undergoing bone marrow transplantation (BMT). Nine patients (median age 23) previously having blood transfusions received BMT at the BMT Center in Pesaro. All patients were prepared for transplantation with cyclophosphamide 50 mg/kg/day (day -6, -5, -4, -3), and 7.5 Gy total nodal irradiation day -1, with a dose rate of 26 cGy/m. Six out of eight evaluable transplanted patients are still surviving 3 to 23 months with a median follow-up of 16.5 months. This preoperative regimen is extremely effective in decreasing rejection following transplantation for severe aplastic anemia. Future investigation must be aimed at the elimination of graft-versus-host-disease and control of fatal infections.

[Laser-photo-radiotherapy in the treatment malignant tumors]

Photoradiation therapy or, as more recently defined, photodynamic therapy (PDT) has been effective in the treatment of several kinds of cancers, above all of the skin, lung, esophagus and bladder. It is based on the preferential retention by tumor and photosensitizing properties of certain porphyrins. We began to investigate this technique experimentally in 1978 and clinically in september 1982, with report of the initial results in 38 patients in 1985. In this paper we describe our more recent experience of PDT in 18 patients affected by different tumors and treated with a new double argon-dye laser system. These tumors included 8 carcinomas of the esophagus, 5 basal cell skin cancers, 2 carcinomas of the lung, 2 squamous cell carcinomas of the oral cavity and 1 early gastric cancer. Clinical results and technical problems of PDT are discussed.

[Meningeal prophylaxis with radiocolloids in childhood leukemia and non-Hodgkin's lymphoma]

Experiences in 13 children treated with radiocolloids (198Au and 32P) applied intrathecally are presented. This treatment may replace the external radiation therapy in prophylaxis or therapy of central nervous system (CNS) involvement in childhood leukemia and non Hodgkin lymphoma. The follow-up median value was 18 months. Ten children were treated for prophylactic aim. Two out of 10 presented meningeal failure 1 month after. Three patients treated for meningosis died for bone marrow relapse without evidence of blasts in CSF sediment.

Effect of hematoporphyrin and red light on AH-130 solid tumors in rats

Thirty Wistar albino rats with a subcutaneous Yoshida hepatoma AH-130 were exposed to 590 to 690 nm light from a high pressure Xenon arc-lamp 24 h after intraperitoneal injection of hematoporphyrin, 5 to 10 mg/kg. In all cases, the tumor decreased rapidly in size, due to necrosis caused both by direct action of the photoactivated porphyrin on the tumor cells and by secondary effects on blood vessels. No injury of normal tissues was detected. At 2 months after phototreatment, no recurrence had occurred and the skin over the tumor area was healed. Favourable therapeutic response was obtained in preliminary experiments by irradiating the Hp-injected tumor-bearing rats with 632.8 nm-light from an He/Ne laser source.

Sensitivity to radiations of Mg2+ and (Ca2+ + Mg2+) ATPase activities associated with erythrocyte membrane fragments

Treatment of disrupted erythrocyte membranes with ionizing radiation induces a partial oxidation of -SH groups (as expected from reported data) and a loss of membrane phospholipids as confirmed by the decrease of membrane amino groups. The resulting disturbance of the membrane assembly strongly affects the membrane bound divalent cation-dependent ATPase activities, possibly by causing the formation of a dead-end enzyme complex unable to complete the ATP splitting cycle.

[Dosimetry of the bladder and the rectum: comparison between the measured and calculated dose (author's transl)]

The authors examine 62 cases of curietherapy in the deep vagina on 21 cases of utero-vaginal applications and make a comparison between two dosimetric methods used to measure the dose to the rectum and to the bladder: the direct measure by the Siemens Gammameter dosimeter and the Chassagne-Horiot method. Very large differences were found between the doses evaluated by the two methods. The values with the direct measure were often found to be higher than the calculated ones. When the measurements were done by different doctors, the result was almost the same.

Ovarian function after pelvic lymph node irradiation in patients with Hodgkin's disease submitted to oophoropexy during laparotomy

Staging laparotomy for Hodgkin's disease was carried out on 110 women in fertile age at the General Surgery Department of Padua Medical School from 1972 to 1977. An oophoropexy was done during the operation. According to the stage the patients underwent radiation therapy that was associated in some cases to chemotherapy. Complete evaluation was possible only in 66 patients. Eighteen out of the 66 had mantle field and para-aortic lymph node chain radiotherapy. One case of amenorrhoea (5.5%) and five pregnancies (27.8%), were found among them. Nineteen had the same type of radiotherapy with MOPP. 3 cases of amenorrhoea (15.8%) and 3 pregnancies (15.8%) were found. Five had total nodal irradiation (TNI) according to Kaplan and all of them had amenorrhoea (100%). Twenty four had TNI associated to MOPP with 24 cases of amenorrhoea (100%). Our results slightly differ from those of other Authors. They showed: 1) that the oophoropexy is not effective using standard surgical technique (probably because of the size of the central shielding) as it causes amenorrhoea in 100% of the cases; 2) the incidence of permanent amenorrhoea from chemotherapy with MOPP is the same as reported by other Authors; 3) the absence of teratogenic effects by chemotherapy in newborns of these patients.

Serum selenium levels in malignant lymphoproliferative diseases

Serum selenium levels were measured in 38 patients with malignant lymphoproliferative diseases (MLD) and in 34 non-hospitalized healthy individuals. Selenium was determined by proton induced x-ray emission. In Hodgkin's disease and non-Hodgkin malignant lymphoma the mean serum levels of selenium were not different from those of the control group. On the contrary lowered mean serum selenium concentrations were observed in the group with chronic lymphocytic leukaemia (5.2 +/- 0.7 microgram/100 ml) as compared to normal individuals (7.9 +/- 0.3 microgram/100 ml). The difference is highly significant (P less than 0.005). A second selenium test was made in 11 out of the 38 patients within 8 weeks from the beginning of radiotherapy or chemotherapy; unchanged levels were found.

[Endocurietherapy in cancer of the bladder. A new technique by implant of 192iridium with Cyponil tubes (author's transl)]

The Authors propose a new technique of interstitial implant in cancer of the bladder based on the direct implant of 192 Iridium with Cyponil tubes. The tubes are roughly 2 metres in length with a radioactive wire in one third of the tube length. These wires are kept in a lead container during the complete implantation of the tube. After opening the bladder the uncharged part of the tube is passed through the inner walls by means of surgical needles. The number of the tubes depends on the size of the tumour and they are placed parallel to each other. They are then drawn until the radioactive part covers the tumour site. One end of the Cyponil tube is then pulled through the urethra and stitched to the skin, the other end is drawn through the surgical incision and attached to the abdominal skin. A Folley catheter is put on the bladder is such a way as to keep it blown up. It is then sutured. A radiography is carried out so as to determine the dosage. At the end of the therapy the stitches of the Cyponil tubes are cut and are removed by extraction.

[Clinical comparison of the kinetics of 99mTc pyrophosphate and 99mTc methylene diphosphonate (author's transl)]

In a series of 10 patients the hematic and plasmatic clearances of 99mTc-pyrophosphate (PYP) and 99mTc-metylene-diphosphonate (MDP) have been studied. The analysis of the results shows that the elimination both hematic and plasmatic of MDP is significantly faster than that of PYP. Moreover the plasmatic elimination of PYP is faster than its hematic elimination. This fact is probably due to a partial absorption of the radionuclide on the surface of the red cells. No significant differences result in the urinary elimination of both radionuclides. As a consequence the MDP has a lower fundus activity and a lower irradiation dose to the blood and to the whole body. For those reasons this radionuclide is proposed as the preferred agent in bones scintigraphy.