The human selenoproteome: recent insights into functions and regulation

Selenium (Se) is a nutritional trace mineral essential for various aspects of human health that exerts its effects mainly through its incorporation into selenoproteins as the amino acid, selenocysteine. Twenty-five selenoprotein genes have been identified in humans and several selenoproteins are broadly classified as antioxidant enzymes. As progress is made on characterizing the individual members of this protein family, however, it is becoming clear that their properties and functions are quite diverse. This review summarizes recent insights into properties of individual selenoproteins such as tissue distribution, subcellular localization, and regulation of expression. Also discussed are potential roles the different selenoproteins play in human health and disease.

Role of brachytherapy in the management of the skull base meningioma. Treatment of skull base meningiomas

BACKGROUND

The treatment of primary and recurrent skull base meningiomas presents a formidable surgical problem.

METHODS

Fifteen patients with primary and recurrent skull base meningiomas were treated by means of interstitial irradiation with iodine 125 (125I) seed implantation. The physical characteristics of 125I enabled the authors to administer a minimum tumor dose ranging from 100 to 500 Gy at a low dose rate of 0.05-0.25 Gy per hour.

RESULTS

All 15 patients are alive at a median follow-up of 29 months. Of the 15 patients, 2 with calcification and 2 without calcification achieved only partial responses. The remaining 11 patients achieved a complete response. No early or late complications were observed.

CONCLUSIONS

From these data, the authors conclude that interstitial irradiation with 125I seeds is an effective, safe, and simple method in the treatment of both recurrent and primary skull base meningiomas.

Intracranial skip metastasis from parotid and facial skin tumors: mechanism, diagnosis, and treatment

Perineural and endoneural tumor spread is a form of metastatic disease in which the primary tumors spread along neural pathways and gain access to noncontiguous regions. Although rare, this type of skip metastasis into the cranial cavity occurs from tumors of the parotid gland and facial skin. Recognition of this process, evaluation of the patient with proper diagnostic procedures, and its treatment are presented.

Continuous low dose rate brachytherapy with high activity iodine-125 seeds in the management of meningiomas

The purpose of this study was to evaluate if meningiomas can be effectively treated with brachytherapy using permanent implantation of high activity I-125 seeds. Thirteen patients with intracranial meningiomas were treated by means of permanent stereotactic implantation of one or more high-activity I-125 seeds. The physical characteristics of I-125 enabled us to deliver a minimum tumor dose ranging from 100 Gy to 500 Gy at a low dose rate of 5 cGy to 25 cGy per hr. Indications for this procedure included recurrence after initial surgery or as primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 25 months. Nine of 13 patients achieved complete resolution of the tumor and in the remaining four, more than 50% reduction in tumor volume was noted at the last follow-up. No late complications were observed. We conclude from this initial data that localized high dose irradiation delivered at a low dose rate using I-125 permanent implantation is an effective, safe, and simple method in the treatment of both recurrent and primary intracranial meningiomas.

Estimation of the mean effective organ doses for total body irradiation from Rando phantom measurements

For the total body irradiation (TBI) procedure, it is necessary to compare the mean dose obtained from the tissue or organs and the estimated dose equivalent value from the computer program. Due to the easy-access of the Rando phantom and repeatability of TLDs and its output, the results from the experiment are quite encouraging for the verification of the dose distributions from total body irradiation at the given prescribed monitor units. The estimation of effective dose equivalent particularly across the lung sections was studied by combinations of using arms as the scatter volume to compensate for the inhomogeneity across the breast portion, as well as using the spoiler for skin-sparing purposes. The results were based upon various beam quality such as 4 MV, 6 MV, and 10 MV X rays. One series of experiments performed for this survey to ascertain the dose equivalent of the tissues was conducted. This paper describes the method and procedure for comparison between the measured data and computed data as a reference in the dosimetry of total body irradiation. Comparison of the measured and computed data for the largest collimated field shows that the calculated dose rates do not differ by more than 2% from the measured data. Because uncertainty is inherent in non-patient-like phantoms, the calculated data may be served as a reference for the dosimetry. For the total body irradiation setup, considering the radiation field size and treatment distances commonly employed, we conclude that the best combination of the patient setup will be (1) laying both arms down as compensation for lung inhomogeneity, and (2) the spoiler, which is made of acrylic about 8 mm thick and functions like a bolus, is needed to reduce the skin sparing effects and contribute the uniform dose distribution. The beam spoiler with the frame stands near the patient during the treatment.

Brachytherapy: a viable alternative in the management of basal meningiomas

Thirteen patients with intracranial meningiomas of the skull base were treated with one or more high-activity iodine-125 seeds. In 11 patients, the seeds were implanted stereotactically under local anesthesia. A minimum dose of 100 to 500 Gy was delivered to the tumor at a dose rate of 5 to 25 cGy/h. Indications for this procedure included recurrence after initial surgery or as the primary modality of treatment in patients who were not candidates for surgery. All 13 patients are alive at a median follow-up of 15 months. Nine of 11 patients (82%) without calcification in their meningiomas achieved complete response. The remaining 4 patients-2 with calcification and 2 without--achieved partial response. No early or late complications were observed. We conclude from our experience that both recurrent and primary meningiomas of the skull base can be treated effectively with permanent iodine-125 brachytherapy.

Effects of multiple sclerosis on occupational and career patterns

The paper will examine the impact of multiple sclerosis on occupational roles and career patterns of 210 persons registered with the Vancouver Island Multiple Sclerosis Society.

METHODOLOGY

210 participants responded to a 17-item mailed questionnaire. Items pertained to participants' demographic characteristics, medical history related to MS, years of career training, occupational history and changes in employment associated with changes in physical status due to MS.

FINDINGS

An initial analysis indicates that the majority of the respondents (64.8%) were 30-59 years of age, the years of greatest career development. Although 97.1% of respondents had held a job at some time in their lives, only 24% were employed on a full or part-time basis at the time of the study. The greatest decrease in employment occurred in health related professions and service industries. Disabilities and symptoms which had the greatest effect on employment were fatigue and muscle weakness. Identified work related problems included inability to work full time and inaccessible environments. The paper will discuss strategies nurses can use to assist employees with MS.

Spine-sparing postmastectomy irradiation

Postoperative irradiation of the chest wall and regional lymphatics following mastectomy for operable breast carcinoma is an effective means of reducing the chance of postoperative locoregional recurrence. The majority of patients who fail will ultimately develop bony metastases, especially in the thoracic and lumbar spinal regions. Our technique of postoperative irradiation avoids exit irradiation of the spine. This is important for patients who may later develop bony metastases or epidural spinal cord compression and require spinal irradiation. The details of the technique are presented.

Extended-field isocentric irradiation for Hodgkin's disease

Extended-field therapeutic irradiation is the treatment of choice for the majority of patients diagnosed with pathologic stages I and II Hodgkin's disease, and total nodal irradiation can be effectively used to treat selected stage III Hodgkin's patients. Standard 100-cm source-to-axis distance extended-field isocentric technique and results are presented.

Dual-field rotational (DFR) technique for total-skin electron-beam therapy (TSEBT)

Comparison of dosimetry measured in a noncylindrical Rando-Alderson phantom by two-field, four-field, and six-field total-skin electron-beam therapy (TSEBT) techniques with our dual-field rotational (DFR) technique reveals a superior dosimetry for the latter. Our technique of dual-field rotational DFR-TSEBT is described in detail, and its advantages and indications for the primary management of cutaneous T-cell lymphoma (CTCL) and Kaposi's sarcoma (KS) are discussed.

Survival of patients with unresectable non-small cell lung cancer following 6,000 rad megavoltage radiotherapy

One hundred and fifty-seven patients with histologically proven, locally advanced, unresectable or inoperable non-small cell lung cancer were treated in a uniform fashion with external-beam megavoltage radiotherapy. Patients received a continuous course of 6,000 rad in 7½ weeks (four fractions of 200 rad per fraction each week). The comparatively high, uncorrected one-year survival rate of 48.7 percent, and uncorrected two-year survival rate of 25.7 percent, would be expected following uniform treatment with a relatively high external-beam tumor dose. The five-year uncorrected actuarial survival rate of 2.7 percent demonstrates that although the median survival can be increased by the use of higher radiation doses and better delivery technique, the ultimate cure rate and prognosis for inoperable and unresectable non-small cell lung cancer remains poor with current equipment and methods of radiotherapy.