Showing papers by "Tufts University published in 1975"

Freeze-etching nomenclature.

Abstract: C3H/He mice chronically infected with murine cYtomegalo virus were given skin allografis fromti histoincompatible BALB/c donors. A significant inicrease in cvtomegalovirus titers occurred within 3 days after placement oJ'the graft in the spleens and kidneYs oJ' the allograft recipients as compared with control aninmals. No significant changes in virus titers were detected in the salivary gland, lung, liver, or blood ofallograJi recipients. These results indicate that the host-versus-graft reaction alone can enihance murine cvtomtiegalovirus in a chronicallY injected host atid maY help explaini the high incidence ofcvvtomegalovirus infection seen after renal and other allograft transplantation

Relations between auditory nerve endings and cell types in the cat's anteroventral cochlear nucleus seen with the Golgi method and nomarski optics

Abstract: Rapid Golgi impregnations of the ascending branches of the auditory nerve fibers and of the types of neurons in the anteroventral cochlear nucleus (AVCN) were studied. Entire ascending branches could be observed, some of these branches project to each subdivision, others do not. There are two main typesof large neurons: the bushy and stellate cells. Criteria were established for identifying unimpregnated bushy and stellate perikarya by means of Nomarski optics, and these criteria were checked by Momarski observations on neurons which had either impregnated dendrites and unimpregnated cell bodies or impregnated portions of perikarya. In this way, the relations of unimpregnated cell bodies to auditory nerve endings were observed. Furthermore, with Nomarski optics, the cytoarchitectonic subdivisions of AVCN could be determined. Differences in the end-bulbs and collateral endings formed by the auditory nerve fibers were distinguished in three of the cytoarchitectonic subdivisions of the AVCN. End-bulbs in the anterior division were much larger than those in the dorsal and ventral parts of the posterior division. The large end-bulbs of Held in the anterior division of the AVCN were consistently associated with the perikarya of bushy cells and not with those of stellate cells. The large end-bulbs are not observed in the posterior division. Thus, bushy cells in the posterior division, although morphologically similar to those in the anterior division, must have a different synaptic organization. This difference may correspond to electrophysiological distinctions in the time-patterns of response recorded in these regions following acoustic stimulation.

Factors affecting entrapment in waiting situations: The Rosencrantz and Guildenstern effect.

Abstract: Seventy-two undergraduates took part in an experimental study of entrapment, in which the passage of time could be viewed either as an investment (increasing the likelihood of goal attainment) or as an expense. Subjects were . given an opportunity to win a large sum of money (the jackpot), which decreased in value over time. In order to win the jackpot, a series of crossword puzzle words had to be solved, some of which were so difficult that the use of a necessary, scarce resource (a crossword dictionary) was required. And in order to obtain the use of this resource, subjects had to wait "in line" until it became available—which it never did. Three variables were varied in a 2X2X2 design: rate of decrement of the jackpot, availability of a chart providing continuous information about this decrement, and information concerning subjects' (presumed) position in line for the dictionary. Entrapment in this waiting conflict was found to be high overall, and was further heightened when (a) the size of the jackpot decreased slowly rather than rapidly, (b) when no payoff chart was made available, and (c) when subjects were told they were first rather than third in line for the dictionary. We've traveled too far, and our momentum has taken over; we move idly towards eternity, without possibility of reprieve or hope of explanation. —Tom Stoppard, Rosencrantz & Guildenstern Are Dead Social psychologists such as Deutsch (1973), Schilling (1960), and others have long been interested in the circumstances underlying entrapment in a variety of conflict situations. One type of conflict in which entrapment commonly occurs, for example, is an auction, in which bidding typically escalates at increasing cost to the participants. In the presence of others with whom they are competing for some desirable object or resource, bidders tend to increase the magnitude of their offers, often above and beyond the objective value of the object in question. Indeed, Shubik (1971) has described an auction game in which entrapment is so intense that a dollar bill may be auctioned off for considerably more than the one dollar at stake! Gambling, similarly, can be interpreted as a conflict situation in which entrapment is likely to occur—particu larly when the gambler wishes to recoup losses he has already incurred and therefore decides to roll the dice "just one more time,"

The specificity and applications of antibodies to helical nucleic acids.

Abstract: (1975). The Specificity and Applications of Antibodies to Helical Nucleic Acid. CRC Critical Reviews in Biochemistry: Vol. 3, No. 1, pp. 45-69.

The attachment of the bacterial chromosome to the cell membrane.

Abstract: We would like to pose three questions: 1) Is the bacterial chromosome attached to the membrane? 2) If so, is it attached at a specific portion of the membrane? 3) Is it attached by a specific region of the DNA? While definitive answers cannot be provided for these questions, we think that the available evidence suggest useful strategies for future work.

Human Isoferritins: Organ Specific Iron and Apoferritin Distribution

Abstract: Summary. Ferritins from human liver, spleen, heart, pancreas and kidney were compared by electrophoresis and isoelectric focusing in polyacrylamide gels, by immunodiffusion against antisera to homologous and heterologous ferritin, and in some cases by their cyanogen bromide peptides. All ferritins appeared to consist of a single species on gel electrophoresis with the exception of heart ferritin which separated into two major components. Small differences in electrophoretic mobility were found in all tissue ferritins. By contrast, all tissue ferritins were found to consist of multiple forms when analysed by gel electrofocusing. At least five isoferritins were found in most tissues, several of which were common to most tissues. At least two were common to all tissues. Those ferritins which were most easily distinguishable electrophoretically, e.g. spleen and heart ferritin, showed the greatest differences on gel electrofocusing. The ferritin profile was characteristic of each organ and was reproducible both within individuals and between individual tissues. There were striking differences in the iron content of the various isoferritins within a tissue. Further, the iron content of isoferritins common to more than one tissue varied with the tissue of origin. Some isoferritins in several organs and all of the isoferritins in pancreas appeared to contain little, if any, iron. All five tissue ferritins contained antigenic determinants in common with liver ferritin. However, an additional antigenic determinant was found in liver ferritin which was not detectable in the ferritins from the other organs.

A genetic analysis of the response to morphine in mice: Analgesia and running

Abstract: Two progenitor strains, BALB/cBy and C57BL/6By, their reciprocal F1 hybrids, and seven of their recombinant-inbred derived lines were used to examine the genetic basis of the response to thermal pain, and morphine analgesia at doses of 2.5, 5.0 and 10.0 mg/kg. Both the latency of response to thermal pain and the analgesic response differed significantly among the various strains tested. Strong genetic determinants appear to control their responses. Analyses of the data did not permit clarification regarding the linkage of these determinants. Photoelectric activity cages were used to test the running response of the same strains to 12.5, 25 and 40 mg/kg morphine sulfate. The genetic determinants for running activity were different from those for analgesia. There is clear evidence for two or more loci controlling the behavior at 60 and 75 min after injection, but not enough information to define the loci involved.

Neural factors and evitability in insect behavior.

Abstract: Compared with more complex behavior patterns involving goal selection, evasive behavior of prey animals elicited by the presence of a natural predator is usually considered to be relatively inevitable and stereotyped. Noctuid moths, while flying in the field at night, show two types of evasive response pattern when their tympanic organs detect the ultrasonic cries of marauding insectivorous bats. Since sound is the sole communication channel between prey and predator, this situation invites neurophysiological and behavioral analysis. When, in the course of studying this behavior, moths are removed by stages from the natural circumstances of this interaction their evasion responses become much less invariant; that is, more evitable. The possible survival value of some evitability in this behavior under natural circumstances is discussed. The afferent nerve response of the noctuid auditory organ is highly stable; therefore, the source or sources of this evitability must lie down-stream in the moth central nervous system. Acoustic interneuronal systems within the thoracic ganglia and the brain have been examined for lapses in responsiveness and for other indications of transsynaptic instability that might correlate with the demonstrated behavioral evitability.

A new method of isolation and some properties of the heavy chain of human plasmin.

Abstract: A method is described by which the heavy chain of human plasmin, obtained by partial reduction of urokinase-activated plasminogen with 2-mercaptoethanol, is adsorbed on lysine coupled to polyacrylamide. The heavy chain is recovered from the adsorbent by elution with 6-aminohexanoic acid (yield 60–65%). Sulfhydryl titrations of the heavy chain showed that the partial reduction involved primarily the cleavage of the sole interchain disulfide bridge of plasmin. Dodecylsulfate-polyacrylamide electro-phoresis gave essentially a single band corresponding to a component of about 60000 molecular weight. The NH2-terminal amino acid was predominantly threonine. 6-Aminohexanoic acid at different concentrations caused significant variations of the sedimentation and diffusion constants of the heavy chain indicating inhibitor-induced conformational alterations of the protein. The present results suggest that in plasmin only the heavy chain is capable of interacting with 6-aminohexanoic acid, and it appears that it is primarily this chain which plays an important role in the inhibition of the enzyme by 6-aminohexanoic acid.

Salt-dependent bacteriophage infecting Halobacterium cutirubrum and H. halobium.

Abstract: MOST molecular genetic mechanisms are sensitive to ionic strength. The isolation of phage for Halobacterium allows a study of genetic adaptation in the extremes of ionic strength. The usual requirement for low ion concentrations is reversed in Halobacterium which maintains intracellular KC1 near saturation1. As a result, macromolecular structure may be altered sufficiently to favour genetic mechanisms that occur rarely or not at all in other organisms. The presence of a unique DNA density distribution2 and RNA-dependent RNA-polymerase3 in Halobacterium suggests that such alterations occur.

Measurement of outcomes of care for stroke patients.

Abstract: A coordinated system of care for stroke patients is established in the community of Fall River, Massachusetts, involving the Stroke Unit of Union Hospital, the Rehabilitation Unit of Earle E. Hussey Hospital, and the Fall River District Nurse Association. Long-Range Evaluation Summary (LRES) data collection forms developed at the Tufts University Medical Rehabilitation Research and Training Center (RT-7) are being used to reflect the functional status of the patient at any given point in time. Of 164 patients the Stroke Unit returned 49% home and the Rehabilitation Unit returned another 9% home. This systematic approach to functional assessment relates the disease-state and disability to outcomes of care. By taking into account the several-fold nature of outcome determination it is possible to analyze program effectiveness because such uniform descriptions, over time, permit us better to relate the population under care, its key characteristics for these purposes, and the comprehensiveness of problem iden...

Dermal histocompatibility and in vitro lymphocyte reactions of three newH-2 mutants

Abstract: Histocompatibility of skin grafts and in vitro lymphocyte reactions of three new H-2 mutants (B6-H-2bg1, B6-H-2bg2, and B6-H-2 bh ) are described. Complementation tests indicated thatH-2bg1,H-2bg2, andH-2 bh were mutations at the same locus (z-1) and allelic withH-2 ba . Two of the lines, B6-H-2bg1 and B6-H-2bg2, appeared identical, although they were of spontaneous and independent origin. The third line, B6-H-2 bh , was unique. Such graft rejection was paralleled by reactivity in the MLR and by the generation of cytotoxic lymphocytes in vitro. The pattern of crossreactivity among antigens specified by these mutant genes supports the notion that thez-1 locus controls multiple specificities. The results indicate that a single point mutation can simultaneously affect histocompatibility, MLR, and CML reactions.

Cytopathological effects of estradiol on the arcuate nucleus of the female rat. A possible mechanism for pituitary tumorigenesis.

Abstract: Large subcutaneous doses (2 mg/21 days) of estradiol valerate (EV) given over several months will induce a prolactin and growth hormone-secreting pituitary tumor in female rats. The medial basal hypothalami (MBHs) of such EV-treated animals were examined at different time intervals with light and electron microscopes to determine whether EV affects the MBH and to relate any observed effects to the process of tumorigenesis. The MBHs of extensively treated rats exhibited profound glial and neuronal changes. The filament content of astrocytes was greatly increased and large dense pleomorphic inclusions filled both astrocytic perikarya and processes. Degenerating neuronal elements have been observed in the neuropil of extensively treated animals. Dark cells identified as M cells were seen to engage in phagocytosis and were loaded with dense inclusions. Some neurons in MBH contained large quantities of lipofuscin that was different in appearance from that of normal females of the same age. The glial reaction developed gradually. At earlier stages of EV treatment there were fewer reactive glia and these contained fewer inclusions. Myelin figures often occurred in these early inclusions. Reactive glia in EV-treated rats did not appear in the preoptic area, dorsomedial nucleus or lateral hypothalamus but were found in ventromedial nucleus. Retired breeders and starvation-stressed rats resembled normal controls. These pathological changes in MBH may result from a direct effect of EV on the hypothalamus. It is possible that, in addition to its effects on the hypophysis, EV suppresses or injures hypophysiotropic cells in MBH, thus releasing pituitary chromophobes from inhibitory hypothalamic influences. This could result in hypersecretion and neoplasia.

Thermal properties of cancellous bone.

Abstract: Specimens of beef bone were analyzed for thermal conductivity and thermal capacity. The thermal conductivity was about 7 X 10(-4) cal/cm/sec/degrees C, that is about the same as for other tissues. As regards thermal capacity, the determination of 0.73 cal/cm2/degrees C also was similar to that in other tissues. Both thermal conductivity and capacity were isotropic with respect to the layer of epiphyseal cartilage, and the orientation of bony trabeculae. Thermal probes were devised heated either by water or by electric current to destroy localized volumes of bone, as in surgery. To achieve necrotizing temperatures, the sizes of such probes and the times of application of heat were determined.

Pericardial rub. Prospective, Multiple observer investigation of pericardial friction in 100 patients.

Abstract: A prospective, multiple observer auscultatory and phonocardiographic study of 100 patients with pericardial friction confirmed the dominant prevalence of triphasic pericardial rubs (56 percent of patients with sinus rhythm). In 9 of 33 patients with various biphasic rub patterns there was summation of the ventricular diastolic rub with the atrial systolic rub, concealing an additional 10 percent of potential triphasic friction. Fourteen of 15 monophasic rubs were audible or recordable only during ventricular systole. Rubs were best heard along the left sternal border in 84 percent of cases and tended to be louder during inspiration than during expiration; in 35 cases there was no respiratory predilection. Twenty-three rubs were palpable. Ten rubs occurred in patients with pericardial effusion, five of whom had tamponade. Extension of the neck did not have a dependable effect on rub intensity.

Amounts and Measures of Amount

Abstract: Anything specified in response to the question, ‘How much?’ may, I suppose, be properly called an amount. But the amounts I want to discuss are those only which are amounts of such things as water or gold, objects designated by what Terence Parsons1 has called ‘applied amount terms’ — phrases like ‘ten pounds of water’ or ‘three teaspoons of gold’, the result of concatenating a numeral, the name of a unit of measurement, and a word or phrase with the grammatical syntax of a mass noun.

Natural history of the familial medullary thyroid carcinoma-pheochromocytoma syndrome and the identification of preneoplastic stages by screening studies: a five-year report.

Abstract: 1. In the fifth year of followup, 8 of 12 original patients thyroidectomized for MTC, diagnosed solely by abnormal calcitonin values, are disease free by all criteria. Elevated calcitonin levels are the only manifestation of active disease in three patients with presumed metastases. 2. Routine annual screening of susceptible individuals is a practical measure and has in 6 cases detected the premalignant condition of G-cell hyperplasia and in 1 patient a premetastatic state of MTC. It is premature to conclude that yearly screening is sufficient to detect all cases of premetastatic disease and for this reason we are recommending a yearly screen with pentagastrin and calcium tests and the more convenient pentagastrin test at 6 month intervals for those in the high-risk age group between 8 and 18. If screening at such intervals proves to be ineffective in preventing the disease in every case, consideration must be given to prophylactic thyroidectomy although we are not currently recommending this precedure. 3. Pentagastrin injection is often a more effective secretagogue for calcitonin than is calcium infusion, but this is not uniformly true. We therefore recommend use of both tests as the most appropriate screening procedure. 4. Epinephrine is a major secretory product of pheochromocytomas in the J-kindred and sequential E/N ratios may be of use in the early detection of pheochromocytoma in other kindreds. 5. Adrenal medullary hyperplasia has been found in 3 adrenal glands and is probably a preneoplastic condition analogous to C-cell hyperplasia.