Showing papers by "Tufts University published in 1978"
TL;DR: Since Metschnikoff's discovery, hundreds of scientists studying dozens of species have reported thousands of studies on these cells, perhaps the most widely recognized of which are those of the eminent English scientists.
Abstract: (First of Two Parts) THE part played by phagocytes in defense against invading pathogens has been recognized since 1883. In that year, Metschnikoff, a Russian zoologist, reported that foreign particles injected into metazoans (in Metschnikoff's experiments, starfish larvae) were taken up by a population of "wandering mesodermal cells" that resided in interstitial tissues.1 He postulated a crucial role in host defense for these wandering cells, which he named "phagocytes." Since Metschnikoff's discovery, hundreds of scientists studying dozens of species have reported thousands of studies on these cells, perhaps the most widely recognized of which are those of the eminent English . . .
2,457 citations
TL;DR: Results suggest that toxin-producing clostridia are responsible for antibiotic-associated pseudomembranous colitis.
Abstract: A substance producing cytotoxicity in tissue culture was detected in stool specimens from all of four patients with pseudomembranous colitis due to antibiotics and in one of 54 with antibiotic-associated diarrhea. These stools also caused enterocolitis when injected intracecally into hamsters. On each occasion, cytotoxicity in tissue culture and enterocolitis in hamsters were neutralized by pretreatment with gas-gangrene antitoxin. The toxicity in both tissue cultures and hamsters could be reproduced with broth cultures of clostridia strains isolated from four of the five stools. These results suggest that toxin-producing clostridia are responsible for antibiotic-associated pseudomembranous colitis.
1,316 citations
TL;DR: Results indicate that C. difficile is the major cause of antibiotic-associated pseudomembranous colitis and offer an explanation for previous studies showing that the cytotoxin of stools from these patients is neutralized by C, sordellii antitoxin.
482 citations
TL;DR: Data suggest that excess pituitary beta-endorphin may play a role in the development of the overeating and obesity syndrome.
Abstract: Small doses of the opiate antagonist naloxone selectively abolished overeating in genetically obese mice (ob/ob) and rats (fa/fa). Elevated concentrations of the naturally occurring opiate beta-endorphin were found in the pituitaries of both obese species and in the blood plasma of the obese rats. Brain levels of beta-endorphin and Leu-enkephalin were unchanged. These data suggest that excess pituitary beta-endorphin may play a role in the development of the overeating and obesity syndrome.
468 citations
TL;DR: In this paper, Griffin presents no new data and omits much of the progress in animal cognition over the past twenty years, and plays the intellectual game of shooting down a theoretical position which is already dead and inventing an imaginary field.
Abstract: capacity to match across modality (Davenport and Rogers, 1970), so the match from tool to function is a reasonable possibility. This does not detract from the clever experiments of SR&B and of P&W, but I would have preferred more context from the rich literature on animal cognition. Griffin presents no new data and omits much of the progress in animal cognition over the past twenty years. Also, he plays the intellectual game of shooting down a theoretical position which is already dead and inventing an imaginary field. This generalization obviously omits his own brilliant work on navigation in birds and echo-location in bats, and his more complete earlier attempt to raise the question of animal awareness (1976 op. at. G, SR&B). Behaviorism was never as monolithic as G's straw man. It lacked adequate technology, data, and theory to justify expending much time or effort in contemplating nonobservables when there were so many interesting things to observe, measure, and control. However, as technology advanced and data were collected, many theoretical structures associated with behaviorism had to be discarded. This resulted in a neobehaviorism with many ideas concerning animal cognition. Much of this work on animal cognition was done with the behavioristic penchant for careful control and was even conducted in alley mazes (Gleitman and Steinman, 1963) and Skinner boxes (Gleitman and Bemheim, 1963). Space does not permit full development of this argument, but a few examples may suffice to illustrate that comparative psychologists have been studying cognitive problems during the past twenty years and are much more in need of a theoretical structure than a fictional field such as cognitive ethology or sociobiology. To illustrate that my own contention is not just an attack on another straw man, the following are areas in which psychologists have recently studied cognitive experiences by animals: (1) cross-modal transfer; (2) surgical and optical sensory recombination; (3) several hundred papers on memory and its development, including reinstatement, rehearsal, and the use of surprising cues; (4) transposition; (5) conditional reaction problems; (6) perceptual constancies; and (7) the perception of barriers and detours. Probably I should also have included Harlow's (1949) formation of learning sets, which bridges the gap between incremental learning and insight. This is a considerable commitment to a comparative and evolutionary analysis of cognition. We need to organize animal cognition into a coherent theoretical structure using the presently abundant data.
454 citations
316 citations
TL;DR: A computerized bibliography from the MEDLARS data base covering the time period of January 1970-March 1976 was retrieved and a table of isoelectric points (pZ) of proteins selected from the literature was prepared.
262 citations
TL;DR: A role for oral vancomycin treatment of antibiotic-associated pseudomembranous colitis which persists for extended periods despite discontinuation of the incriminated antimicrobial is suggested.
233 citations
TL;DR: An analysis of relapse patterns revealed that 33% of relapses occur as solitary extranodal “skip” recurrences that when treated with radical local treatment may result in long disease‐free survival.
Abstract: The cumulative 10 year lymphoma experience of a teaching hospital and two of its affiliated institutions was reviewed. From this group, a series of 39 cases of regionally localized primary extranodal lymphomas (Ann Arbor Stages IE and IIE) were selected for study. This group of patients was analyzed for response to initial curative treatment and factors influencing prognosis. The disease-free survival rate following initial treatment is 41% and the rate is 51% if those treated for a single relapse are included. Factors which clearly influence prognosis in this group are stage (extent of disease) at presentation and Rappaport histologic subclassification. The relationships of anatomic site and age to prognosis independent of other factors are unclear. There appears to be an association between sites of involvement in Waldeyer's Ring and the gastrointestinal tract seen both initially and in sites of relapse. An analysis of relapse patterns revealed that 33% of relapses occur as solitary extranodal "skip" recurrences that when treated with radical local treatment may result in long disease-free survival. The latter is one of several findings which suggest that a modification of the current Ann Arbor staging system may be necessary to encompass certain unique features of this group of tumors.
198 citations
TL;DR: Tests provocative of calcitonin secretion each year for seven years to members of a pedigree now numbering 107 to detect familial medullary thyroid carcinoma in a premetastatic stage found later carcinomas were smaller, were unilateral and occurred in younger patients.
Abstract: To detect familial medullary thyroid carcinoma in a premetastatic stage, we administered tests provocative of calcitonin secretion (infusion of calcium or pentagastrin or both) each year for seven years to members of a pedigree now numbering 107. Since 1970, 21 patients converted from normal to abnormal secretory responses (two separate tests in which calcitonin levels exceeded 0.58 ng per milliliter). Twenty of 21 glands removed showed C-cell hyperplasia, and eight of the 20 also showed foci of carcinoma. As compared to the 12 patients with tumors detected during the first year of screening, all of whom had bilateral carcinoma (seven of 12 with local metastases), later carcinomas were smaller (mean diameter of 0.2 vs. 0.8 cm), were unilateral (in all but two cases) and occurred in younger patients (mean age of 14.9 vs. 36.4 years), and none had detectable metastases.
178 citations
TL;DR: Results indicate that clindamycin-induced enterocolitis in hamsters is a model of human disease and implicate toxin-producing clostridia as responsible agents.
Abstract: Stools from a patient with antibiotic-associated colitis and cecal contents from a hamster with clindamycin-induced enterocolitis were compared in a cytotoxicity assay to determine common properties. Both specimens produced actinomorphic changes in human amnion cells at 10(-7) dilutions. The toxin was acid labile, heat labile, nonether extractable, non-dialyzable, and produced maximum activity at 60% with ammonium sulfate precipitation. Cytotoxicity was neutralized with clostridial antitoxin but not with equine serum. Clostridium difficile was recovered in high concentrations in specimens from both the hamster and patients. The supernatants of these C. difficile strains produced cytoxic effects which were also neutralized by clostridial antitoxins. These results indicate that clindamycin-induced enterocolitis in hamsters is a model of human disease and implicate toxin-producing clostridia as responsible agents.
TL;DR: Dietary carbohydrate is an important factor in reversing the fall in serum T 3 caused by fasting, and men show more significant changes in serum thyroid hormone concentrations during fasting than women do, and absorption of T 3 is not altered during fasting.
Abstract: To assess the effect of starvation and refeeding on serum thyroid hormones and thyrotropin (TSH) concentrations, 45 obese subjects were studied after 4 days of fasting and after refeeding with diets of varying composition. All subjects showed an increase in both serum total and free thyroxine (T 4 ), and a decrease in serum total and free triiodothyronine (T 3 ) following fasting. These changes were more striking in men then in women. The serum T 3 declined during fasting even when the subjects were given oral L-T 4 , but not when given oral L-T 3 . After fasting, the serum reverse T 3 (rT 3 ) rose, the serum TSH declined, and the TSH response to thyrotropin-releasing hormone (TRH) was blunted. Refeeding with either a mixed diet ( n = 22) or a carbohydrate diet ( n = 8) caused the fasting-induced changes in serum T 3 , T 4 , rT 3 , and TSH to return to control values. In contrast, refeeding with protein ( n = 6) did not cause an increase in serum T 3 or in serum TSH of fasted subjects, while it did cause a decline in serum rT 3 toward basal value. The present data suggest that: (1) dietary carbohydrate is an important factor in reversing the fall in serum T 3 caused by fasting; (2) production of rT 3 is not as dependent on carbohydrate as that of T 3 ; (3) men show more significant changes in serum thyroid hormone concentrations during fasting than women do, and (4) absorption of T 3 is not altered during fasting.
TL;DR: Observations suggest that both coliforms and anaerobes are important pathogens in intra-abdominal sepsis, although the different types of microbes appear to play distinctive roles in the sequence of pathological events.
Abstract: Intra-abdominal sepsis that involves multiple aerobic and anaerobic bacteria derived from the colonic flora was studied in Wistar rats to determine the relative roles of various microbial species. The rats challenged with pooled colonic contents showed a biphasic disease. Initially, there was acute peritonitis, Escherichia coli bacteremia, and high mortality. In rats that survived this acute peritonitis stage, intra-abdominal abscesses developed, and anaerobic bacteria were the preponderant organisms. Subsequent experiments showed that antibiotics directed against coliforms prevented mortality, whereas agents active against anaerobes reduced the incidence of abscesses. Challenges with Escherichia coli alone produced bacteremia and death, whereas pure cultures of Bacteroides fragilis caused intra-abdominal abscesses. These observations suggest that both coliforms and anaerobes are important pathogens in intra-abdominal sepsis, although the different types of microbes appear to play distinctive roles in the sequence of pathological events.
TL;DR: The finding that IgA protease activity is linked specifically to the pathogenic neisseria suggests that the enzyme may be involved in the pathogenesis of neisserial infection.
Abstract: IgA proteases are extracellular enzymes of bacteria that have human immunoglobulin A of the IgA1 subclass as their only known substrate. The identification of this enzyme in neisseria prompted us to determine whether IgA protease production correlates with pathogenicity within this genus. Multiple clinical isolates of Neisseria gonorrhoeae, N. meningitidis and eight species of non-pathogenic neisseria that commonly colonize the normal human nasopharynx were examined for IgA protease activity. All N. gonorrhoeae and N. meningitidis strains were enzyme positive; all non-pathogenic strains were negative. Among meningococci, the enzyme occurred in strains carried harmlessly in the nasopharynx as well as those isolated from systemic infections. Because mucosal immune defense is largely mediated by antibodies of the IgA isotype, the finding that IgA protease activity is linked specifically to the pathogenic neisseria suggests that the enzyme may be involved in the pathogenesis of neisserial infection.
TL;DR: The inferior parietal lobule of the monkey is the homologous region to the supramarginal and angular gyri in man, subserving language and related cortical functions, and positive cells in the thalamic sections were located by injecting eight monkeys with retrogradely transported HRP.
Abstract: The inferior parietal lobule (IPL) of the monkey is the homologous region to the supramarginal and angular gyri in man, subserving language and related cortical functions. We have examined specific zones of the IPL by injecting eight monkeys with retrogradely transported HRP, and located the positive cells in the thalamic sections with the assistance of an X-Y plotter and reference to the atlas of Olszewski ('52). Projections to the IPL were found in the following thalamic nuclei: Anterior (Anterior Medial, Anterior Ventral); Lateral (Ventral Anterior, Ventral Anterior magnocellularis, Ventral Lateral caudalis, Pulvinar oralis, medialis, lateralis and inferior, Lateral Posterior and Lateral Dorsal); Medial (Medialis Dorsalis densocellularis, parvocellularis, and multiformis); Midline and Intralaminar (Centralis densocellularis, Centralis lateralis, Centralis inferior, Centralis superior lateralis, Subfascicularis parvocellularis, Paracentralis and Parafascicularis); and Posterior (Limitans, Suprageniculatus and Geniculatus Medialis magnocellularis).
A major projection to the superior portion of the IPL was from the anterior nuclei and Paracentralis of the intralaminar group. Ventralis Lateralis and oral Pulvinar projected primarily to the anterior-inferior portion of the IPL, whereas Lateral Posterior projected most strongly to the anterior and superior portion. The major projection of the lateral Pulvinar was to the mid-superior portion of the IPL and to area 19. The projections of the inferior Fulvinar were heaviest to area 19, but there was some overlap in the mid-superior portion of the IPL with the medial and lateral Pulvinar. The major projection from the posterior thalamic nuclear complex was to the mid-IPL.
The heterogeneous input from the thalamus to the IPL was not anticipated on the basis of prior anterograde or retrograde degeneration studies, and suggests that classical subdivisions of specific and associational thalamic nuclei should be revised with the axonal transport methods of study.
TL;DR: CEA is a useful tumor marker in patients with locally advanced or metastatic medullary thyroid carcinoma and that CEA and calcitonin can be produced by the same neoplastic cell populations.
Abstract: Six patients with locally advanced and/or metastatic medullary thyroid carcinoma, of both familial and non-familial types, had markedly elevated serum concentrations of calcitonin and carcinoembryonic antigen (CEA). The highest serum CEA concentrations were found in those patients with the most extensive disease and correlated with the extent of serum calcitonin elevation. Immunocytochemical studies revealed positive staining for CEA and calcitonin in tumor cells, and these results were confirmed by correlative radioimmunoassays of tumor extracts for CEA. Patterns of calcitonin and CEA immunoreactivity in tissue sections were similar but not identical. While most tumor cells contained both CEA and calcitonin, some groups of tumor cells that were strongly stained for calcitonin did not stain for CEA. In contrast to the granular staining pattern for calcitonin, CEA immunoreactivity tended to be diffusely distributed throughout the cytoplasm or was concentrated at the plasma membranes. Normal and hyperplastic C cells, on the other hand, showed strong staining for calcitonin but did not contain immunoreactive CEA. It is concluded that CEA is a useful tumor marker in patients with locally advanced or metastatic medullary thyroid carcinoma and that CEA and calcitonin can be produced by the same neoplastic cell populations.
TL;DR: Periodical serum gentamicin assays should be performed to ensure that the peak serum levels attained are adequate, but not unnecessarily high, in seriously ill patients in a fluctuating physiological state.
Abstract: Although it is widely recommended that serum levels of aminoglycoside antibiotics be monitored by assay, the justification for this approach has not been clearly presented. A number of studies indicate that serum levels of these agents cannot be predicted reliably on the basis of simple dosage formulae; the major confounding factors being abnormalities of renal function and of extracellular fluid volume in addition to less well defined variables such as fever and anaemia. The influence of haemodialysis and concomitant administration of carbenicillin further complicate dosage estimations in patients with renal insufficiency. On the basis of currently available data, it is reasonable to suggest an optimum range of 5 to 8 microgram/ml for peak serum levels of gentamicin. There are no reliable studies from which to derive a comparable value for trough (pre-dose) concentrations. The relative importance of peak and trough values for nephrotoxicity and ototoxicity is an unresolved subject of controversy. However, it seems possible that neither of these individual values, but rather the 'area under the time-concentration curve' is the major risk factor for toxicity. In view of the unpredictability of serum levels, especially in seriously ill patients in a fluctuating physiological state, periodical serum gentamicin assays should be performed. The main objective of these assays is to ensure that the peak serum levels attained are adequate, but not unnecessarily high.
TL;DR: The problem of getting a machine to feel is not a task that invites solution simply by sophisticated imlovations in programming, but rather, if at all, by devising new sorts of hardware as mentioned in this paper.
Abstract: It has seemed important to many people to claim that computers cannot in principle duplicate various human feats, activities, happenings. Such aprioristic claims, we have learned, have an embarrassing history of subsequent falsification. Coa~Ltrary to recently held opinion, for instance, computers can play superb che~zkers and good chess, can produce novel and unexpected proofs of nontrivial theorems, can conduct sophisticated conversations in ordinary if tightly circumscribed English. The materialist or computerphile who grounds an uncomplicated optimisim in this ungraceful retreat of the skeptics, however, is in danger of installing conceptual confusion in the worst place, in the foundations of his own ascendant view of the mind. The triumphs of Artificial Intelligence have been balanced by failures and false starts. Some have asked if there is a pattern to be discerned here. Keith Gunderson has pointed out that the successes have been with task-oriented, sapient features of mentality, the failures and false starts with sentient features of mentality, and has developed a distinction between program-receptive and programresistant feature~ of mentality. 1 Gunderson's point is not what some have hoped. Some have hoped he had found a fall-back position for them: viz., maybe machines can think but they can't feel. His point is rather that the task of getting a machine to feel is a very different task from getting it to think; in particular it is not a task that invites solution simply by sophisticated imlovations in programming, but rather, if at all, by devising new sorts of hardware. This goes some way to explaining the recalcitrance of mental features like pain to computer simulation, but not far enough. Since most of the discredited aprioristic thinking about the limitations of computers can be seen in retrospect to have stumbled over details, I propose to conduct a more detailed than usual philosophic thought experiment. Let us imagine setting out to prove the skeptic wrong about pain by actually writing a pain program, or designing a pain-feeling robot. I think the complications eEountered will prove instructive. The research strategy of computer simulation has often been misconstrued by philosophers. Contrary to the misapprehensions innocently engendered by
TL;DR: Large tumors, those with capsular infiltration, and tumors with spread to lymph nodes had a higher recurrence rate, Operative spill increased the chance of abdominal recurrence and several critical factors of surgical technique were not studied.
Abstract: Surgical data derived from the 606 patients in the National Wilms' Tumor Study have been analyzed to determine the effect of surgical technique on results of treatment. In addition to surgical excision of the tumor, patients were treated with chemotherapy and radiation therapy according to the study protocol. Under these controlled conditions, certain aspects of surgical technique which have traditionally been thought to be important for success appear to be irrelevant. Physical characteristics of the tumor, preoperative rupture and vascular invasion by tumor were not associated with higher relapse rates. Large tumors, those with capsular infiltrations, and tumors with spread to lymph nodes higher recurrence rate. Operative spill increased the chance of abdominal recurrence. There was no evidence that early ligation of the renal vein was of value in prevention of recurrence, nor was incomplete removal of tumor associated with an increase in relapse rate. Although several critical factors of surgical technique were not studied, it is clear that others are not significant and need not be continued.
TL;DR: When a diagnostic test is reported as normal, the clinician generally uses it only to rule out certain diseases, but if properly interpreted, it may help to differentiate among diagnoses that yield normal results with different frequencies.
Abstract: When a diagnostic test is reported as normal, the clinician generally uses it only to rule out certain diseases. However, if properly interpreted, the normal value may help to differentiate among diagnoses that yield normal results with different frequencies. A simple method permits the extraction of such information. The physician estimates the probability of various diagnoses and then combines these estimates with the anticipated frequency of negative results for each disease under consideration. (N Engl J Med 298:486–489, 1978)
TL;DR: It is reported here that plasmid-containing resistant cells take up tetracycline by a different transport mechanism from that of sensitive cells, which seems to be responsible for at least part of the difference in tetrACYcline inhibition of sensitive as compared to resistant cells.
Abstract: TETRACYCLINES are broad-spectrum bacteriostatic antibiotics which act by inhibiting protein synthesis1,2 However, their usefulness in combating bacterial infection has been sharply curtailed by the widespread occurrence in bacteria of tetracycline resistance encoded by genes located on extrachromosomal DNA elements called plasmids3,4 In many bacteria, notably Enterobacteriaceae, Pseudomonas and Staphylococcus, plasmid-mediated tetracycline resistance is inducible; the resistance level can be increased by preincubation of the cells in sub-inhibitory amounts of tetracycline5–8 Coincident with induced resistance is the induced synthesis of a plasmid-encoded inner membrane protein which we have designated TET protein8–10 Synthesis of this protein (and presumably most of the resistance determinant) is negatively regulated; a represser has been partially purified11 However, the mechanisms for plasmid-mediated tetracycline resistance are not yet clear, and there seems to be no degradation of the antibiotic in resistant cells10,12,13 Although resistant cells accumulate less tetracycline than do sensitive cells14,15, the moderately reduced uptake does not explain the much larger difference in sensitivity to the drug10,16,17 We report here that plasmid-containing resistant cells take up tetracycline by a different transport mechanism from that of sensitive cells This altered transport seems to be responsible for at least part of the difference in tetracycline inhibition of sensitive as compared to resistant cells
TL;DR: It is demonstrated that local failure is the major factor affecting the quality of life in patients who underwent abdomino-perineal resection for adenocarcinoma of the colon without adjuvant radiotherapy, and even R that does not occur would have a significant benefit by prolonging a pain-free useful life for those who fall from this disease.
Abstract: One hundred thirty eight consecutive patients who underwent abdomino-perineal resection for adenocarcinoma of the colon without adjuvant radiotherapy were studied retrospectively. They were analyzed in respect to failure rate and effect of local and distant metastases on the quality of their lives. These patients were followed for a minimum of 2 years and none were lost to follow-up. The patients in whom the tumor completely penetrated through the wall showed significant failure rates, 5196 R there were no positive nodes and 79% If there were positive nodes. The 5 year absolute survival data was 47.2% for all stages and 31.6% for Dukes' Stage C 5 . These results are comparable to other published series. 3,9,12,16 Of the 56 patients who failed, 57% had local symptoms without symptoms of distant metastases. An additional 11% had local pelvic symptoms for an average of 12.7 months prior to death with symptoms of distant metastases only during the terminal portion of their disease. Symptoms of distant metastases alone occurred In 20%. Symptomatic local and distant metastases occurred in 11%. Among patients who had symptoms of distant metastases, the average duration of these symptoms was 7.5 months prior to death compared with 12.2 months average for patients who had local symptoms. This study demonstrates that local failure is the major factor affecting the quality of life. Adjuvant radiotherapy should increase survival rates, but even R that does not occur, it would have a significant benefit by prolonging a pain-free useful life for those who fall from this disease.
TL;DR: It is shown that rheumatoid factors from serum Jos bind to nucleosomes, the repeating histone–DNA subunit of chromatin in human and animal IgG, as well as in animals from many species.
Abstract: NATURAL antibodies against antigenic sites on the Fc region of human and animal IgG are referred to collectively as rheumatoid factors (RF) and they represent one of the immunological hallmarks of rheumatoid arthritis (RA). Thus, the synovial fluid and tissue of RA patients contain large immune complexes which at least in part consist of RF1–4, and RF are present in serum in the majority of patients with definite or classical RA. Recent studies have demonstrated that purified and pepsin-digested polyclonal RF of IgG class from an RA serum (Han), in addition to reacting specifically with IgG, also bind to an antigen associated with cell nuclei from many species5. Furthermore, essentially 100% of the anti-nuclear antibodies (ANA) of two sera (Han, Jos) was absorbed by insolubilised human IgG; the antibodies which could be eluted from this immunosorbant bound to cell nuclei, and this binding was specifically inhibited by Fc fragments of human IgG5,6. We show here that RF from serum Jos bind to nucleosomes, the repeating histone–DNA subunit of chromatin.
TL;DR: Despite the historical significance of European decolonization after the Second World War, there has been no serious interpretive account of it as an overall process as discussed by the authors, and no systematic attempt to separate carefully the chief variables to be analyzed, to assign them weights of relative importance, and to coordinate them in an historical and comparative manner.
Abstract: Despite the historical significance of European decolonization after the Second World War, there has been no serious interpretive account of it as an overall process. A number of excellent case studies exist analyzing specific policies or periods in the imperial capitals or in the colonial territories, and there are several chronologically complete surveys of the decline of European rule overseas. These have neither been directed nor followed, however, by studies attempting to conceptualize synthetically the entire period. In default of a wide-ranging debate over the character of decolonization as an historical movement, a kind of conventional wisdom has grown up attributing the differences in the British and French experiences to a combination of their respective imperial traditions and the governing abilities of their domestic political institutions. As yet, there has been no systematic attempt to separate carefully the chief variables to be analyzed, to assign them weights of relative importance, and to coordinate them in an historical and comparative manner. This essay hopes to open discussion of these questions.
TL;DR: The data suggest that hemispheric specialization is related to perceptual processing and experience and not merely to the acoustic properties of stimuli.
TL;DR: The anisotropic Kepler problem as discussed by the authors is a one-parameter family of classical mechanical systems with two degrees of freedom, and it has been shown to change the orbit structure of the system dramatically when # ≥ 1.
Abstract: The anisotropic Kepler problem is a one-parameter family of classical mechanical systems with two degrees of freedom When the parameter # = 1, we have the well known Kepler or central force problem As # increases beyond 1, we introduce more and more anisotropy into the Kepler problem As we show below, this changes the orbit structure of the system dramatically When p = 1, the system is completely integrable and the orbit structure is well understood With the exception of certain collision orbits, all orbits are closed and lie on two dimensional tori in the case of negative total energy For p > 1, we keep the same potential energy, but make the kinetic energy anisotropic, ie the kinetic energy becomes
TL;DR: In addition to their important role as accessory pigments in photosynthesis, carotenoids also participate as agents which protect cells and tissues against the potentially harmful effects of visible radiation as discussed by the authors.
Abstract: In addition to their important role as accessory pigments in photosynthesis, carotenoids also participate as agents which protect cells and tissues against the potentially harmful effects of visible radiation. They seem to play a unique role in this regard, for there are at least three separate mechanisms which can be invoked to explain the protective aspects of carotenoid function. These involve interrupting the potentially destructive photochemical reactions by quenching the triplet state of chlorophyll, physically inactivating the highly reactive singlet state of oxygen ( $^1\Delta_g$ ) which can be formed photochemically, and finally serving as an oxidizable substrate to protect other molecules and processes from photodestruction. These protective effects, which were first elucidated in mutant strains of photosynthetic organisms, have been shown to have an even wider role in nature, for many non-photosynthetic systems utilize carotenoid pigments for similar protective purposes.
TL;DR: Most women harbor distinctive bacterial populations in the cervix and vaginal vault, and neither low concentrations of bacteria nor the culture techniques accounted for these differences.
TL;DR: It is concluded that the genes that determine the expression of infectious xenotropic virus in NZB mice segregate independently from those that are involved in the autoimmune disease of these animals.
Abstract: The relationship between expression of xenotropic virus and the development of autoimmunization was studied in the progeny of crosses between New Zealand Black (NZB) and SWR mice. The (F1 X SWR) and F2 progeny segregated into three phenotypes: high-virus, low-virus, and virus-negative; F1 and (F1 X NZB) progeny were always high-virus. Autoantibodies, immune deposit nephritis and lymphomas developed in the progeny of these crosses. The virological phenotype of the animal could be dissociated from the presence of either autoantibodies or nephritis. For example, mice that expressed titers of virus as high as the NZB parent failed to develop signs of autoimmunization, even up to 24 mo of age. By contrast, some (F1 X SWR) and F2 mice that expressed low titers of virus developed autoimmune disease. Furthermore, a proportion of virus-negative mice produced autoantibodies and were found to have typical immune deposit nephritis. No viral antigens could be detected in the renal lesions of such virus-negative animals. By contrast with the dissociation between expression of virus and occurrence of nephritis, the presence of antibodies to DNA correlated with the development of renal lesions. We conclude that the genes that determine the expression of infectious xenotropic virus in NZB mice segregate independently from those that are involved in the autoimmune disease of these animals.