COVID-19 impact on timing of brachytherapy treatment and strategies for risk mitigation

PURPOSE

The purpose of this study was to highlight the importance of timely brachytherapy treatment for patients with gynecologic, breast, and prostate malignancies, and provide a framework for brachytherapy clinical practice and management in response to the COVID-19 pandemic.

METHODS AND MATERIALS

We review amassing evidence to help guide the management and timing of brachytherapy for gynecologic, breast, and prostate cancers. Where concrete data could not be found, peer-reviewed expert opinion is provided.

RESULTS

There may be a significant negative impact on oncologic outcomes for patients with gynecologic malignancies who have a delay in the timely completion of therapy. Delay of prostate or breast cancer treatment may also impact oncologic outcomes. If a treatment delay is expected, endocrine therapy may be an appropriate temporizing measure before delivery of radiation therapy. The use of shorter brachytherapy fractionation schedules will help minimize patient exposure and conserve resources.

CONCLUSIONS

Brachytherapy remains a critical treatment for patients and may shorten treatment time and exposure for some. Reduced patient exposure and resource utilization is important during COVID-19. Every effort should be made to ensure timely brachytherapy delivery for patients with gynecologic malignancies, and endocrine therapy may help temporize treatment delays for breast and prostate cancer patients. Physicians should continue to follow developing institutional, state, and federal guidelines/recommendations as challenges in delivering care during COVID-19 will continue to evolve.

Interobserver reliability in describing radiographic lung changes after stereotactic body radiation therapy

PURPOSE

Radiographic lung changes after stereotactic body radiation therapy (SBRT) vary widely between patients. Standardized descriptions of acute (≤6 months after treatment) and late (>6 months after treatment) benign lung changes have been proposed but the reliable application of these classification systems has not been demonstrated. Herein, we examine the interobserver reliability of classifying acute and late lung changes after SBRT.

METHODS AND MATERIALS

A total of 280 follow-up computed tomography scans at 3, 6, and 12 months post-treatment were analyzed in 100 patients undergoing thoracic SBRT. Standardized descriptions of acute lung changes (3- and 6-month scans) include diffuse consolidation, patchy consolidation and ground glass opacity (GGO), diffuse GGO, patchy GGO, and no change. Late lung change classifications (12-month scans) include modified conventional pattern, mass-like pattern, scar-like pattern, and no change. Five physicians scored the images independently in a blinded fashion. Fleiss' kappa scores quantified the interobserver agreement.

RESULTS

The Kappa scores were 0.30 at 3 months, 0.20 at 6 months, and 0.25 at 12 months. The proportion of patients in each category at 3 and 6 months was as follows: Diffuse consolidation 11% and 21%; patchy consolidation and GGO 15% and 28%; diffuse GGO 10% and 11%; patchy GGO 15% and 15%; and no change 49% and 25%, respectively. The percentage of patients in each category at 12 months was as follows: Modified conventional 46%; mass-like 16%; scar-like 26%; and no change 12%. Uniform scoring between the observers occurred in 26, 8, and 14 cases at 3, 6, and 12 months, respectively.

CONCLUSIONS

Interobserver reliability scores indicate a fair agreement to classify radiographic lung changes after SBRT. Qualitative descriptions are insufficient to categorize these findings because most patient scans do not fit clearly into a single classification. Categorization at 6 months may be the most difficult because late and acute lung changes can arise at that time.

Hiding single photons with spread spectrum technology

We describe a proof-of-principal experiment demonstrating the use of spread spectrum technology at the single photon level. We show how single photons with a prescribed temporal shape, in the presence of interfering noise, may be hidden and recovered.

External and middle ear trauma resulting from ear impressions

When taking an impression of the external ear canal and ear, the audiologist is engaged in an invasive procedure whereby a foreign body is first placed into the ear canal and then removed. There is always an element of risk for significant medical problems when a clinician is performing an invasive procedure. Although some minor patient discomfort and, at times, some slight trauma to the ear canal occur when taking ear impressions, the incidence of significant trauma to the external or middle ear appears to be low. The purpose of this report is to provide some illustrative cases of significant external and middle ear trauma as a result of taking impressions of the external ear. Audiologists are advised to develop and implement an appropriate risk management program for taking ear impressions to reduce the potential risks associated with this procedure to their patients and to their practices.

Skull metastasis from renal cell carcinoma. Case report and literature review

Metastatic tumors to the head and neck are uncommon. We report a case of renal cell carcinoma that presented as an epidermal inclusion cyst on the forehead. The forehead is an exceedingly uncommon site for renal cell metastases. We review the biology of tumor metastases and explore the pathways by which infraclavicular tumors spread to the head and neck. We then discuss the clinical appearance and management of metastatic renal cell carcinoma.

rsc: a novel oncogene with structural and functional homology with the gene family of exchange factors for Ral

A novel oncogene, rsc (rabbit squamous cell carcinoma), has been identified from a DMBA-induced rabbit squamous cell carcinoma using gene transfer and the nude mouse tumorigenesis assay. A full-length cDNA has been isolated and sequenced. rsc has potent tumorigenic activity in nude mice (latency <4 weeks), but does not induce focus formation or anchorage independent growth. The oncogene resulted from the fusion of rHR 23A (a rabbit homologue of yeast Rad 23) with a member of the ral-GDS family which we named rgr (ral-GDS related). Deletion analysis demonstrated that the oncogenic potential resides in the Rgr portion of the gene. Rgr is 40% identical overall to Ral-GDS, with identity increasing to 72% over a 100 amino acid region of the catalytic domain. Biochemical experiments indicate that Rgr has GTP/GDP exchange activity for Ral, providing evidence that this pathway is associated with tumorigenesis. The linkage between the Ral pathway and tumorigenesis by a molecule in the Ral-GDS gene family (Ral-GDS being a known effector for Ras) will open the way for the characterization of this pathway and provide an important tool to understand its biological function.

Antigenicity and nutritional value of selected milk proteins and their hydrolysate in growing rats

Two liquid diets containing selected milk proteins (SMP) or its small peptide hydrolysate (SPH) were fed to growing rats for 2 wk and the effects on growth, nitrogen balance, and small intestine adaptation were determined. Residual antigenicity of the SPH diet as measured by immunodot was reduced by 98.8%. Nitrogen intakes were not different. Weight gain was significantly higher in rats fed the SMP diet. In contrast, the absolute nitrogen balance was similar, suggesting that protein storage was identical with the two diets. A better nitrogen digestion-absorption rate with the SPH diet was observed as evidenced by the significantly increased fecal excretion with the SMP diet. Small intestine adaptation showed no difference between the two diets for mucosal weight, protein content/10 cm as well as for sucrase, glucoamylase, and N-aminopeptidase total activity/10 cm or specific activity (mU/mg protein). The DNA content of the mucosa/10 cm was significantly higher suggesting a mucosal hyperplasia in the SPH diet. The data suggest that in rats the SPH diet leads to nitrogen retention and small intestine adaptation similar to that of the SMP diet, despite better body weight gain by the latter.

Mutagenic effects of tumorigenic neutron radiation

A fraction of thymic lymphomas induced by high LET neutron radiation contains activating mutations (single-base substitutions) in the ras genes. To determine whether such mutations are the result of the interaction of high LET radiation with cellular DNA, we have utilized an in vitro model system to screen and isolate neutron-radiation-induced mutants. With that aim, we irradiated the PL61 hamster cell line with 0.4 MeV neutrons. This cell line contains linked copies of the gpt and neo(r) genes, which permits selection for large or small alterations, depending on the selection imposed. Mutants selected for large alterations represented 98.2% of the total. When selection for small mutations was imposed, 9 clones grew. The molecular and biochemical analysis of these clones revealed that 5 of them had identifiable mutations in the gpt gene, consisting of small insertions and deletions, but no single-base substitutions were detected. This represents the first sequence characterization of neutron-induced mutants. The results obtained are consistent with the notion that the ras point mutations identified in the neutron-induced tumors are most likely detected due to the strong selective advantage that they confer to the host cell, but they probably arose during tumour evolution, since they represent a negligible proportion of the total number of alterations induced by neutron radiation.

In vitro lymphocyte proliferation with milk and a casein-whey protein hydrolyzed formula in children with cow's milk allergy

Discordant results have been reported about the role of lymphocyte proliferation assays in patients with cow's milk allergy. We studied the peripheral blood mononuclear cell response of 10 children with cow's milk allergy by means of a lymphocyte proliferation test to determine the diagnostic value of this assay, the clinical tolerance of a new therapeutic hydrolyzed formula, and the evolution of lymphocyte proliferation after 3 months of a cow's milk-free diet with the hydrolyzed formula. The lymphocyte proliferation at the time of diagnosis in the patients with cow's milk allergy was not statistically different from the results in the control group. The proliferation test performed after 3 months of diet with the hydrolyzed formula and restriction of cow's milk protein showed that the cellular proliferation remained globally the same compared with the proliferation at the time of diagnosis. The hydrolyzed formula proteins induced a lower cellular proliferation than milk proteins in patients with cow's milk allergy. Our results suggest that the lymphocyte proliferation test cannot be recommended for diagnostic purposes. However, in patients with cow's milk allergy the proliferation test affirmed the absence of immunogenicity of the hydrolyzed formula because it induced no significant T-cell activation.

Link design for nondirected wireless infrared communications

We optimize the design of a short-range communication system using nondirected line-of-sight IR radiation. We propose a receiver structure comprising a spherical thin-film optical filter and a truncated spherical lens that can significantly outperform an optimized planar-filter system. We can make the passband of the spherical filter arbitrarily narrow without constraining the field of view by using an arbitrarily large filter radius. We argue that a truncation angle of 90° maximizes the receiver field of view when a spherical filter is used. We jointly optimize the transmitter radiation pattern and receiver optical components. Numerical results show that 269 mW of transmitted signal power is sufficient to achieve 100 Mbit/s throughout a 4-m-radius cell with high background irradiance.

An overexpressed N-ras proto-oncogene cooperates with N-methylnitrosourea in mouse mammary carcinogenesis

The induction of tumors with chemicals and the production of transgenic animals are two experimental approaches to study oncogene involvement in carcinogenesis. The combination of both strategies offers an excellent model system to study tumor development. This study analyzes the potential cooperation of N-methylnitrosourea (MNU) treatment and N-ras proto-oncogene overexpression in tumorigenesis in transgenic mice. The overexpression of the N-ras proto-oncogene in these animals is associated with development of mammary tumors and lymphomas. After MNU treatment we analyzed tumor incidence and latency, levels of transgene expression, and pattern of ras mutations in codons 12, 13, and 61 of H-, K-, and N-ras genes in both tumor types. Transgenic mice treated with MNU had significantly (P < 0.001) shorter latency of appearance of mammary tumors [8.6 +/- 3.0 (SD) months] than phosphate-buffered saline-treated transgenics (12.8 +/- 2.3 months). All mammary tumors overexpressed the N-ras transgene and lacked ras mutations. Moreover, MNU-treated transgenics had an incidence and latency of lymphomas similar to that of MNU-treated nontransgenic mice. No significant differences in incidence of point mutations (K-ras codon 12 or 13 and N-ras codon 61) in lymphomas were seen between these two groups. All lymphomas overexpressed the N-ras transgene, except for those carrying a K-ras point mutation. Overexpression of the N-ras proto-oncogene cooperates with non-ras genes mutated by MNU in mouse mammary carcinogenesis. Conversely, N-ras proto-oncogene overexpression does not show cooperation with MNU in lymphomagenesis in our system. This study suggests that proto-oncogene overexpression may be a mechanism of activation of the ras pathway, alternative to point mutation. Similarly to actions for ras genes activated by point mutation, overexpression of the N-ras protooncogene predisposes to tumorigenesis and cooperates with a carcinogen in tumorigenesis. The possibility that ras overexpression plays a role in human breast tumorigenesis requires active investigation.

Dietary components of malt extract such as maltodextrins, proteins and inorganic salts have distinct effects on glucose uptake and glycogen concentrations in rats

As shown previously, glycogen deposition in liver and muscle is significantly greater in rats fed a diet containing barley malt extract than in those fed diets containing glucose or starch. We investigated whether particular components of malt extract (glucose oligomers, inorganic salts, protein) were responsible for this effect. Food-deprived rats were fed diets containing carbohydrates of different chain lengths [glucose, maltose, maltodextrins or malt carbohydrates (84-86 g/100 g)] in the presence and absence of inorganic salts (2 g/100 g) and maltodextrin diets (78 g/100 g) containing either no protein or 20 g casein/100 g. Dietary glucose oligomers caused higher blood glucose concentrations than consumption of glucose or maltose but had no significant influence on liver or muscle glycogen. Salt addition resulted in higher muscle glycogen concentrations but had no effect on blood glucose or liver glycogen. Hepatic glycogen concentrations were significantly greater in rats fed casein compared with those fed no protein. We propose that consumption of malt extract has the following advantages over consumption of diets containing glucose or maltose: 1) better glucose absorption related to the presence of glucose oligomers, 2) greater hepatic glycogen concentrations associated with the protein in malt extract, and 3) greater glycogen concentrations in muscle due to the presence of inorganic salts.

Effects of two protein hydrolysates on growth, nitrogen balance and small intestine adaptation in growing rats

The effects of feeding 2 protein hydrolysates, one prepared by controlled pepsin and pancreatic protease (including elastase II) hydrolysis of milk proteins (PPPH) and the other a di- and tripeptide bacterial protease hydrolysate of bovine albumin (DTPH), on the growth, nitrogen balance and small intestine adaptation of growing rats were analyzed. Two groups of 3-week-old rats (8 rats/group) were fed the liquid diets ad libitum for 2 weeks. The diets had the same caloric, nitrogen, carbohydrate and lipid contents. The amino acid compositions fulfilled the needs of growing rats. The diet differed in the original proteins, the hydrolysis technique used and the molecular weights of the peptides. Nitrogen intakes were similar. Although there was no difference in weight gain, nitrogen balance was significantly higher in the rats fed the PPPH diet (day 4-day 6:PPPH, 60 +/- 4%, DTPH, 25 +/- 5%; day 12-day 15: PPPH, 58 +/- 3%; DTPH, 30 +/- 5%). The stool nitrogens were identical, suggesting improved nitrogen storage in the rats fed the PPPH diet. Small intestine adaptation showed that the rats on the PPPH diet had significantly more protein (mg) and DNA (microgram) per 10 cm of the jejunum (PPPH, 25.6 +/- 2, 393 +/- 20; DTPH: 15.7 +/- 2, 258 +/- 23) and sucrase-specific activity and per microgram of DNA (PPPH, 133 +/- 5.7, 9.7 +/- 0.5; DTPH, 113 v 5, 7 +/- 1). The N-aminopeptidase-specific activity was the same in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Practical and clinical aspects of multifactorial therapy in obesity]

In the present study the effect of a combination of protein-restricted modified hypocaloric diet and a behavioural therapy in 125 obese patients was analyzed. Patients were divided in two groups: 96 patients were instructed and controlled by practitioners (group 1) and 29 patients were followed in our out-patient clinic (group 2). After 14 weeks on diet a mean weight reduction of 10.6 kg in group 1 and of 9.8 kg in group 2 was observed. Furthermore, a significant decrease in systolic and diastolic blood pressure and in mean cholesterol and triglyceride values was seen. Our results show the good effect of a modified protein-sparing fast in obese patients. However, it has to be emphasized that the most promising results have been those utilizing not only a nutritional but also a behavioral approach.

Refeeding of rats fasted 36 hours with five different carbohydrates and with malt extract: differential effects on glycogen deposition in liver and muscle, on plasma insulin and on plasma triglyceride levels

Rats fasted for 36 h were refed for 1, 2, 4 or 6 h with a diet containing 12 g/100 g casein, 2 g/100 g NaCl and 86 g/100 g glucose, fructose, maltose, sucrose, starch or malt extract. Blood glucose reached constant levels after 1 to 2 h of refeeding. The increase in plasma insulin paralleled food intake rather than the increase in blood glucose. Plasma triglycerides decreased upon refeeding starch, maltose and malt extract and increased with sucrose and fructose. Recovery of absorbed carbohydrates was highest in rats refed malt extract. Glycogen deposition in muscle was highest in rats fed malt extract and lowest in those fed fructose; sucrose yielded intermediate values. Glucose, maltose and starch resulted in muscle glycogen depositions slightly lower than those obtained with malt extract. In liver, sucrose and fructose were better precursors for glycogen than glucose and starch. With carbohydrates containing only glucose units, much more glycogen was found to be deposited in total muscle than in liver. This asymmetry was less notable or even was reversed with sucrose and fructose. Glycogen deposition in muscle and in liver is influenced by the carbohydrate used for refeeding, and muscle, rather than liver, is the main glycogen storing tissue.

Hilger facial nerve stimulator: a 25-year update

Percutaneous nerve excitability testing using the Hilger facial nerve stimulator was introduced about 25 years ago. The test is reliable, easy to use, and inexpensive; it continues to be the most frequently used method for predicting prognosis of facial nerve disorders. Between 1966 and 1974, we recorded 10,243 nerve excitability tests on 865 patients with a mean of 3.29 tests for each peripheral branch and 3.43 for the trunk. Using a multiple regression model, we determined the effect on nerve stimulation values of age, sex, race, diabetes, hypertension, partial or complete clinical paralysis, diagnosis of herpes zoster, year of testing, and eventual facial paralysis recovery profile. We discuss statistical reliability, provide a table of interpretive results, and offer "tips and traps" invaluable to the practitioner. A prospective study of 25 patients with residual facial paralysis was evaluated by two separate otolaryngologists to determine intertester reliability.

The influence of the initial state of hydration on endocrine responses to exercise in the heat

This study examines the effect of the initial state of hydration on hormone responses to prolonged exercise in the heat. Five subjects at two initial hydration levels (hypohydrated and hyperhydrated) were exposed to a 36 degrees C environment for 3 h of intermittent exercise. During exercise, the subjects were either fluid-deprived, or rehydrated with water or an isotonic electrolyte sucrose solution (ISO). Both the stress hormones, adrenocorticotropic hormone and cortisol, and the main fluid regulatory hormones, aldosterone, renin activity (PRA) and arginine vasopressin (AVP), were measured in blood samples taken every hour. Prior hyperhydration significantly reduced initial AVP, aldosterone and PRA levels. However, except for AVP, which responded to exercise significantly less in previously hyperhydrated subjects (p less than 0.05), the initial hydration state did not influence the subsequent vascular and hormonal responses when the subjects were fluid-deprived while exercising. Concurrent rehydration, either with water or with ISO, reduced or even abolished the hormonal responses. There were no significant differences according to the initial hydration state, except for PRA responses, which were significantly lower (p less than 0.01) in previously hyperhydrated subjects who also received water during exercise. These results indicate that prior hydration levels influence only slightly the hormonal responses to prolonged exercise in the heat. Progressive rehydration during exercise, especially when extra electrolytes are given, is more efficient in maintaining plasma volume and osmolarity and in reducing the hormonal responses.

[Differentiated enteral feeding in the post-aggression phase in polytrauma patients. Comparison of a high calorie nutritionally defined diet (whole protein high calorie diet) with a peptide diet]

Two groups of 10 patients with an identical mean injury score (25 + 5) were treated from day 3 after injury until day 10 with a whole protein high caloric (WPHC) diet (group A) or with a peptide diet (PD) (group B). Intake of calories, protein, water, Na+ and K+ was measured daily as well as excretion of urine, Na+ and K+. Gastric reflux, bowel movement and plasma levels of Na+ and K+ were registered and the nitrogen balance and Na+/K+ quotient in urine were calculated daily. Clinically both diets were well tolerated, with low gastric reflux and no diarrhea. The calculated caloric demand could be covered in group A on day 7 post-injury (or day 4 of enteral nutrition) and in group B on day 11 post-injury (or day 7 of enteral nutrition). The caloric intake in group A remained significantly higher on days 4-10. There was no difference in nitrogen balance. Total enteral Na+ and fluid intake were significantly lower in group A, but some additional parenteral Na+ had to be given to keep plasma Na+ levels in the normal range. There was no difference in urine output between the 2 groups; therefore, there was a significant fluid retention in group B. Interestingly, the Na+/K+ quotient in urine was significantly higher in group A. The low Na+ intake might influence the back flow of interstitial edema in the 'flow phase'. This diet seems to be adequate, especially for the nutrition of burn patients and of patients with cardiac disease, and can cover the high caloric needs of polytraumatised patients within a few days.