Antigen presentation by hapten-specific B lymphocytes. II. Specificity and properties of antigen-presenting B lymphocytes, and function of immunoglobulin receptors

The studies described in this paper were designed to examine the ability of hapten-binding murine B lymphocytes to present hapten-protein conjugates to protein antigen-specific, Ia-restricted T cell hybridomas. BALB/c B cells specific for TNP or FITC presented hapten-modified proteins (TNP-G1 phi, TNP-OVA, or FITC-OVA) to the relevant T cell hybridomas at concentrations below 0.1 microgram/ml. Effective presentation of the same antigens by B lymphocyte-depleted splenocytes, and of unmodified proteins by either hapten-binding B cells or Ig spleen cells, required about 10(3)-to 10(4)-fold higher concentrations of antigen. The use of two different haptens and two carrier proteins showed that this extremely efficient presentation of antigen was highly specific, with hapten specificity being a property of the B cells and carrier specificity of the responding T cells. The presentation of hapten-proteins by hapten-binding B lymphocytes was radiosensitive and was not affected by the depletion of plastic-adherent cells, suggesting that conventional APCs (macrophages or dendritic cells) are not required in this phenomenon. Antigen-pulsing and antibody-blocking experiments showed that this hapten-specific antigen presentation required initial binding of antigen to surface Ig receptors. Moreover, linked recognition of hapten and carrier determinants was required, but these recognition events could be temporally separated. Finally, an antigen-processing step was found to be necessary, and this step was disrupted by ionizing radiation. These data suggest a role for B cell surface Ig in providing a specific high-affinity receptor to allow efficient uptake or focusing of antigen for its subsequent processing and presentation to T lymphocytes.

Numerical analysis of the thermochemical tooth damage induced by laser radiation

A numerical model is developed to predict zones of thermochemical tooth damage induced by laser radiation. Particular attention is devoted to pulp denaturation, enamel fracture and caries sterilization treatment dependence on laser energy and other beam parameters.

Evaluation of the Arizona health care cost-containment system

This article evaluates Arizona's alternative to the acute portion of Medicaid, the Arizona Health Care Cost-Containment System (AHCCCS), during its first 18 months of operation from October 1982 through March 1984. It focuses on the program's implementation and describes and evaluates the program's innovative features. The features of the program outlined in the original AHCCCS legislation included: Competitive bidding, prepaid capitation of providers, capitation of the State by the Health Care Financing Administration, assignment of gatekeepers, beneficiary copayment, private administration, inclusion of private and public employees and county financed long-term care. An assessment of implementation during the second 18 months of the program reporting on more recent developments and is now being prepared by SRI International.

Epidemiology, health policy, and resource allocation: the Israeli perspective

Israel represents a developed country as far as demand and consumption of health services are concerned. The analysis of the Israeli health system reveals a significant trend of expansion in the intensity and the utilization of health services as well as an accelerated development of sophisticated technology, while the percentage of Gross National Product used for health expenditure remained constant and even decreased. Competing needs, reflecting population growth, a rapid aging process, new areas of treatment, and changes in use of health services, illustrate the aggravating issue of setting priorities. The permanent dilemma of the health system is oscillation between opposite trends: enlargement of public eligibility and technological capabilities and economic reduction and budget limitations. Is there a possibility that the insufficiencies of the system are built into patterns of thinking of those in the system, into its structure, and into its organization of health services delivery? Does the formulation of health policy influence, in terms of the outcomes of the system, priorities and allocation of resources? Does the process of decisionmaking reflect in an appropriate manner the epidemiologic data? Under the objective constraints, decisionmaking and health policy formulation become critical determinants of the ability to cope more efficiently and effectively with growing and changing needs. The authors suggest an alternative strategy of health decisionmaking that is more instrumental in order to prevent setbacks and to open new horizons for the future.

The distribution of enkephalin immunoreactive neuronal cell bodies in the monkey brain: preliminary observations

The distribution of enkephalin immunoreactive cell bodies was studied in the central nervous system of colchicine-treated monkeys. They followed a distribution pattern similar to enkephalin immunoreactive nerve fibers and terminal fields, and were found throughout much of the spinal cord and brain. Large numbers of enkephalin immunoreactive cell bodies were seen in the brainstem, hypothalamus and in telencephalic nuclear areas. In most regions, the distribution of enkephalin immunoreactive cell bodies in the monkey brain was similar to that reported for the rat.

The distribution of enkephalin immunoreactive fibers and terminals in the monkey central nervous system: an immunohistochemical study

Using immunohistochemical techniques, the distribution of met-enkephalin fibers and terminals was studied in the central nervous system of adult old-world monkeys. Areas which showed the greatest density of immunoreactivity included substantia gelatinosa, nucleus tractus solitarius, nucleus parabrachialis, substantia nigra, median eminence, globus pallidus (external segment), patches within the striatum and the region of nucleus accumbens and the olfactory area. Striking and discrete zones of enkephalin immunoreactive fibers and terminals which did not conform to known nuclear boundaries were observed in the latter areas. The distribution of enkephalin in the monkey is compared to what has been described in the rat central nervous system. In general, the two species are similar, however, differences were observed in some areas including the hypoglossal nucleus, substantia nigra and in the region of the nucleus accumbens and olfactory area. The results are discussed with regard to the possible functional significance of enkephalin localization in regions related to regulation of pain, mood, and autonomic function.

A primate analogue of amphetamine-induced behaviors in humans

The effects of amphetamine on individual and social behaviors were studied in two colonies of rhesus monkeys. After an initial base-line period, each animal, in turn, received low chronic drug administration for 3 weeks. Between each drug period new base-line data were collected. During amphetamine administration, there was a significant increase in the following behaviors: time spent in "sit tense" postures, frequency of orienting, and frequency of agonistic behaviors. In addition, significant changes were seen in the time spent in proximity with other members of the group. The results are discussed both in terms of across-animal changes as well as with regard to social factors, rank in the hierarchy, and affiliative relationships.

Recent biosynthetic studies on beta-lactam antibiotics

Recent experimental observations on the cell-free formation of penicillins and cephalosporins in protoplast lysates from C. acremonium are described. Conversion of radiolabelled penicillin N into deacetoxycephalosporin C is described. A proposal is made about the general types of mechanism involved in these conversions.