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.

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.

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.

Indications for surgical replacement of the mitral valve. With particular reference to common and uncommon causes of mitral regurgitation.

Mitral valve replacement is considered when there is severe mitral stenosis, severe mitral insufficiency or a combination of the two. Ordinarily, surgical replacement is considered only for patients who are in functional classes III or IV and do not respond to medical management. Patients with symptomatic mitral stenosis should be treated with mitral commissurotomy whenever possible. Patients selected for commissurotomy should have a pliable valve, no other major valve dysfunction, sinus rhythm, no systemic embolism and good left ventricular function. Early operation is not ordinarily required. Mitral insufficiency may require mitral valve replacement in six rather common settings: rheumatic disease, rupture of mitral chordae tendineae, postinfarction rupture of a papillary muscle, intractable infective endocarditis, floppy mitral valve and malfunction of a prosthetic valve. Rupture of mitral chordae tendineae can usually be recognized from the history, physical examination, echocardiogram and angiocardiogram. Severe left ventricular papillary muscle dysfunction is usually due to cardiac infarction, and occurs within the first 9 days of infarction. When only a papillary muscle tip is ruptured the patient may survive long enough for a mitral valve replacement. In infective endocarditis, operation is more often needed because of congestive heart failure than because of refractory infection. Evidence of mitral stenosis or insufficiency in a patient with a previously implanted prosthetic valve usually indicates an urgent need for study and early operation. Uncommon causes of mitral incompetence that may require valve replacement are endocardial fibroelastosis, Marfan's syndrome, calcified mitral anulus, osteogenesis imperfecta, methysergide-induced heart disease and carcinoid heart disease.

Circulating Charcot-Leyden crystals in the hypereosinophilic syndrome.

A patient who had malignant melanoma associated with the hypereosinophilic syndrome died of cardiovascular thrombotic lesions. Widespread tissue eosinophilia was accompanied by numerous Charcot-Leyden crystals in the tumor as well as in various organs, including the renal tubules. A unique observation, not previously described, is the finding of Charcot-Leyden crystals in the thrombi and vessels, including the renal glomeruli. While little is known of the significance of Charcot-Leyden crystals, it is speculated that the circulating crystals injure the endothelium and trigger intravascular coagulation, resulting in thrombosis. A search for the crystals in blood and/or urine may be of additional aid in the evaluation of the extent of the thrombotic process. A special staining method is proposed to facilitate recognition of the crystals, since these are virtually not visualized by routine stain. With the use of such a staining method, future observations in other cases of the hypereosinophilic syndrome may elucidate the role of Charcot-Leyden crystals in the pathogenesis of the thrombotic cardiovascular lesions of this syndrome.

Glycaemic response and hydrogen production to blenderised and polymeric enteral nutrition formulas.

Complete enteral nutrition preparations include blenderised formulas based on natural foods with some fibre content and also low-residue polymeric formulas. This study examines the effect of the different fibre content of two commercial formulas (6.4 g/l and 0.25 g/l) on glycaemic and insulin response and hydrogen production in the colon during constant rate administration in 11 normal subjects. No difference in serum glucose and insulin levels was found. No rise in hydrogen production was detected with either formula suggesting no carbohydrate malabsorption. The quantity or nature of fibre present in blenderised formulas does not modify the pattern of carbohydrate absorption compared to a low-residue polymeric formula. However, this does not preclude other possible physiological effects of fibre content upon gastrointestinal motility and 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.

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.

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.

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.

[Practical and clinical aspects of multifactorial therapy in obesity]. / Eine multifaktorielle Adipositastherapie in Praxis und Klinik.

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.

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.

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.

Enzymes involved in 3,5-diaminohexanoate degradation by Brevibacterium sp.

Cell-free extracts of Brevibacterium sp. L5 grown on DL-erythro-3,5-diaminohexanoate were found to contain a 3-keto-5-aminohexanoate cleavage enzyme that converts 3-keto-5-aminohexanoate and acetyl-coenzyme A (CokA) to 3-aminobutyryl-CoA and acetoacetate and a deaminase that coverts L-3-aminobutyryl-CoA to crotonyl-CoA. The cleavage enzyme has been purified extensively, and some of its properties have been determined for comparison with the 3-keto-6-acetamido-hexanoate cleavage enzyme of Pseudomonas sp. B4. The deaminase has been partially purified and characterized. Both the cleavage enzyme and the deaminase are induced by growth on 3,5-diaminohexanoate. The presence of these and other accessory enzymes in Brevibacterium sp. extracts accounts for the results of earlier tracer experiments which showed that C-1 and C-2 of 3-keto-5-aminohexanoate are converted mainly to acetoacetate and acetate, whereas C-3 to C-6 are converted mainly to 3-hydroxybutyrate or its coenzyme A thiolester. The enzymes observed in extracts of Brevibacterium sp. can account for the conversion of 3,5-diaminohexanoate to acetyl-CoA.

Pathway of lysine degradation in Fusobacterium nucleatum.

Lysine was fermented by Fusobacterium nucleatum ATCC 25586 with the formation of about 1 mol each of acetate and butyrate. By the use of [1-14C]lysine or [6-14C]lysine, acetate and butyrate were shown to be derived from both ends of lysine, with acetate being formed preferentially from carbon atoms 1 and 2 and butyrate being formed preferentially from carbon atoms 3 to 6. This indicates that the lysine carbon chain is cleaved between both carbon atoms 2 and 3 and carbon atoms 4 and 5, with the former predominating [1-14C]acetate was also extensively incorporated into butyrate, preferentially into carbon atoms 3 and 4. Cell-free extracts of F. nucleatum were shown to catalyze the reactions of the 3-keto,5-aminohexanoate pathway of lysine degradation, previously described in lysine-fermenting clostridia. The 3-keto,5-aminohexanoate cleavage enzyme was partially purified and shown to have properties much like those of the clostridial enzyme. We conclude that both the pathway and the enzymes of lysine degradation are similar in F. nucleatum and lysine-fermenting clostridia.

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.

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.