Strongly dispersive transient Bragg grating for high harmonics.

We create a transient Bragg grating in a high-harmonic generation medium using two counterpropagating pulses. The Bragg grating disperses the harmonics in angle and can diffract a large bandwidth with temporal resolution limited only by the source size.

Calibration of a high harmonic spectrometer by laser induced plasma emission.

We present a method that allows for a convenient switching between high harmonic generation (HHG) and accurate calibration of the vacuum ultraviolet (VUV) spectrometer used to analyze the harmonic spectrum. The accurate calibration of HHG spectra is becoming increasingly important for the determination of electronic structures. The wavelength of the laser harmonics themselves depend on the details of the harmonic geometry and phase matching, making them unsuitable for calibration purposes. In our calibration mode, the target resides directly at the focus of the laser, thereby enhancing plasma emission and suppressing harmonic generation. In HHG mode, the source medium resides in front or after the focus, showing enhanced HHG and no plasma emission lines. We analyze the plasma emission and use it for a direct calibration of our HHG spectra.

Inhibition of in vivo and in vitro infectivity of Leishmania donovani by tunicamycin.

Leishmania donovani 2S strain promastigotes were rendered non-infectious to mice and mouse peritoneal macrophages by treatment with tunicamycin, an inhibitor of N-linked protein glycosylation. Concentrations of tunicamycin (1-10 micrograms ml-1) that reduced promastigote infectivity to 2% or less of control levels had little or no measurable effect on the in vitro growth of the promastigotes. Tunicamycin has no apparent effect on the entry of promastigotes into macrophages. These results indicate that the sugar residues of glycoproteins are important to the promastigote during the early stages of macrophage infection.

Experimental infections of the multimammate rat (Mastomys natalensis) with Leishmania donovani and Leishmania major.

The susceptibility of the multimammate rat, Mastomys natalensis, to experimental infections with Leishmania donovani and L. major was examined. Inoculations of L. major promastigotes into the skin resulted in nonulcerating lesions in which parasites could be detected for more than 30 weeks later. Intravenous inoculations of L. donovani promastigotes produced visceral infections characterized by a continuing increase in splenic parasite burdens and liver parasite burdens which peaked during the first few weeks of infection and gradually decreased as the disease became chronic. L. donovani could be isolated from the blood throughout the infection, and promastigotes were cultured from the spleens of rats inoculated intradermally. Thus, the multimammate rat appears to be a good reservoir host for these parasites.

Activity of pentostam (sodium stibogluconate) against cutaneous leishmaniasis in mice treated with neutralizing anti-interferon-gamma antibody.

Studies with Leishmania donovani in the mouse have demonstrated that an intact T cell compartment is required for effective anti-leishmanial therapy using pentavalent antimony compounds such as Pentostam (sodium stibogluconate), suggesting that the in vivo efficacy of drug treatment is at least partially immune-based. Similarly, Leishmania-infected, immunodeficient human patients including those with acquired immunodeficiency syndrome (AIDS) generally relapse following therapy with antimonials. However, sodium stibogluconate is directly parasiticidal in vitro, in the absence of T cells or T cell products. Using a model of a cutaneous form of leishmaniasis, in which susceptible BALB/c mice were infected with Leishmania major, we investigated whether the antileishmanial activity of the drug demonstrated a requirement for interferon-gamma (IFN-gamma), a cytokine produced during a T helper cell type 1 (Th1) immune response and known to contribute to resistance to infection, and whether drug therapy affected the nature of the antileishmanial response. Lesion development was suppressed in mice treated from the onset of infection with sodium stibogluconate alone, and in animals treated with sodium stibogluconate plus a neutralizing anti-IFN-gamma antibody, and tissue parasite burdens were approximately 10,000-fold less at the end of therapy in both groups compared with controls. Lesion development was similarly suppressed in mice with established lesions treated with either sodium stibogluconate alone, or sodium stibogluconate plus anti-IFN-gamma antibody. The production of IFN-gamma by cells from infected animals was somewhat increased immediately following therapy with sodium stibogluconate, an effect that was not long-lasting, while interleukin-4 (IL-4) production was not affected by treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Manual therapy: a critical assessment of role in the profession of physical therapy.

Interest in manual therapy appears to continue to grow among physical therapy clinicians and educators throughout the world even though the underlying concepts and techniques have not been justified by a knowledge base. The purposes of this article are to critically assess the role of manual therapy within the physical therapy profession and to provide an introduction to the other articles in this special issue. Eisner's model of explicit, implicit, and null curricula is used as a framework for our analysis and our discussion of manual therapy. The explicit area of manual therapy includes discussions of the definition and the role of manual therapy, the scientific rationale for manual therapy, and manual therapy in education and a comparison of manual therapy evaluative frameworks. The implicit area deals with the role of clinical decision making and critical thinking in manual therapy in education and rehabilitation. In the null (unaddressed) area of manual therapy, we suggest directions for future development and research.

Feline giardiasis: observations on natural and induced infections.

The excretion of Giardia sp cysts in the feces of naturally and artificially infected cats fluctuated sporadically, and cysts were undetectable several times during 7 weeks of observation. The mean prepatent period for Giardia infection in 7 cats was 9.6 days (range, 5 to 16 days). The amount of the cyst inoculum did not appear to affect the length of the prepatent period. Six of 11 cats had clinical signs consistent with those of giardiasis. Clinical signs and cyst excretion were eliminated after treatment with metronidazole or furazolidone. Moderate oral or parenteral doses of corticosteroids produced little, if any, alteration in the infection. Postmortem examination of 1 inoculated cat revealed Giardia trophozoites in the jejunum and upper portion of the ileum but not in the duodenum, lower portion of the ileum, cecum, or colon. Giardia cysts isolated from cat feces produced infection in Mongolian gerbils but not in C57BL/6J mice.

In search of clinical excellence.

This article was presented as a lecture at the 1995 Combined Sections Meeting by Joseph P. Farrell, MS, PT, who received the Orthopaedic Section's Paris Distinguished Service Award. He was recognized for service to the Orthopaedic Section in the area of manual therapy and for the formation of the American Academy of Orthopaedic Manual Physical Therapists (AAOMPT). Clinical excellence is a journey that every clinician should commence early in his/her career. The purpose of this paper is to discuss clinical excellence and its importance to the physical therapy profession. To address this topic, the following items will be discussed: 1) clinical competency and clinical expertise; 2) communication and patient management in the current era of health care reform; 3) politics relating to manual therapy; 4) the role of manual therapy in our profession; 5) clinical residency educational programs; and 6) the academic and clinician role in education. The author concludes that if physical therapy is a profession of excellent clinicians, then the physical therapy profession can survive evolving changes in the health care system.

Physician executive contracts: negotiating the future.

Once viewed as a matter of standard protocol, physician executive contracts have become as complex as the health care industry itself. Historically, hospital administration and physicians negotiated a few key points, then sent the ideas to an attorney for insertion of standard legalize and boilerplate. Today, physician executive contracts are an important part of the changes in health care. They not only cover traditional hospital and physician relations, but increasingly apply to new types of relations (such as employment) between hospitals and physicians, physicians and physicians, and health plans and physicians. In this article, we will explore both the "content" and the "context" of physician executive contracts. Content will deal with the specific provisions typically included in contracts. Context will address issues associated with preparing for and negotiating a contract.

Making change pay. Survey: more hospitals tap compensation as a tool of change.

No matter how much you say you want your health care organization's performance levels to change, you've got to put your money where your wish list is. That, in a nutshell, is the bottom-line finding of this year's Hay Hospital Compensation Survey, exclusively in this issue. But while the concept is simple, the execution is not, as the authors point out in their analysis.

Ultrafast X-ray Auger probing of photoexcited molecular dynamics.

Molecules can efficiently and selectively convert light energy into other degrees of freedom. Disentangling the underlying ultrafast motion of electrons and nuclei of the photoexcited molecule presents a challenge to current spectroscopic approaches. Here we explore the photoexcited dynamics of molecules by an interaction with an ultrafast X-ray pulse creating a highly localized core hole that decays via Auger emission. We discover that the Auger spectrum as a function of photoexcitation--X-ray-probe delay contains valuable information about the nuclear and electronic degrees of freedom from an element-specific point of view. For the nucleobase thymine, the oxygen Auger spectrum shifts towards high kinetic energies, resulting from a particular C-O bond stretch in the ππ* photoexcited state. A subsequent shift of the Auger spectrum towards lower kinetic energies displays the electronic relaxation of the initial photoexcited state within 200 fs. Ab-initio simulations reinforce our interpretation and indicate an electronic decay to the nπ* state.

Site-specific immunity to Leishmania major in SWR mice: the site of infection influences susceptibility and expression of the antileishmanial immune response.

Inbred strains of mice usually develop either of two divergent patterns of infection in response to Leishmania major. Resistant mice, which develop self-limiting infections, respond immunologically with the activation of gamma interferon-secreting Th1 helper T cells, while nonhealing infections in susceptible mice are characterized by the proliferation of interleukin-4-secreting Th2 cells. Development of these divergent responses is dependent primarily on the strain of mouse infected, although factors such as the infective dose, species, and strain of parasite can also influence the degree of resistance. In this study, we show that a single mouse strain, SWR, can develop totally divergent patterns of infection depending on the site of parasite inoculation. Both SWR mice and highly susceptible BALB/c mice developed progressive, ultimately fatal disease when inoculated in the dorsal skin over the base of the tail. However, SWR mice infected in the hind footpad developed far less severe infections, which were for the most part controlled, whereas BALB/c mice infected in this site developed severe, nonhealing lesions. Production of gamma interferon and interleukin-4 and measurement of immunoglobulin E levels in serum were used to assess the degree of Th1 and Th2 cell activation in infected mice. Cytokine profiles early in infection had characteristics of a mixed Th1-Th2 response and were similar in SWR mice infected at either site. These early cytokine responses were not predictive of the ultimate disease outcome, since lymph node cells from healing mice eventually produced higher levels of gamma interferon than did those from nonhealing mice, and healing mice had lower levels of immunoglobulin E in serum, suggesting a functional bias toward Th1 cell activity in these animals. The differential ability of SWR mice to heal infections at different cutaneous sites provides a new model for the study of resistance to cutaneous leishmaniasis. Unlike traditional models of infection in which resistant and susceptible strains of mice are compared, this model allows for the study of factors that contribute to healing and nonhealing infections in a genetically identical strain of mouse.

Comparison of T-cell responses in self-limiting versus progressive visceral Leishmania donovani infections in golden hamsters.

Leishmania donovani infection in golden hamsters was studied as a model for human kala-azar. After intradermal inoculation of L. donovani amastigotes, hamsters developed positive skin reactions (delayed-type hypersensitivity [DTH]) to parasite antigens and lymphoid cells from these hamsters proliferated to parasite antigens in vitro and transferred DTH reactivity to normal recipients. In contrast, hamsters infected by the intracardial route developed progressive visceral infections and failed to respond to skin test antigens. Spleen cells, lymph node cells, and peripheral blood lymphocytes (PBLs) from these hamsters were unresponsive to parasite antigens in vitro, and spleen cells failed to transfer DTH to normal recipients. Spleen cells, but not PBLs, displayed depressed responses to T-cell mitogens and also suppressed the proliferative response of cells from hamsters inoculated intradermally. Removal of adherent cells restored the capacity of spleen cells, but not PBLs, to respond to parasite antigens. The nonadherent population of these spleen cells also transferred DTH to normal recipients. The adherent suppressor cells, which have the characteristics of macrophages, appear to be localized to the spleen and are apparently not responsible for the failure of peripheral lymphoid cells to respond to antigen. These studies suggest that hamsters with visceral infections develop a population of antigen-reactive cells and that in the absence of suppression these cells may express functional activities, including the capacity to elicit DTH responses.

Back school programs. The young patient.

CC's treatment goals were all met with the exception of eliminating the AMNT sign. Slump-sit right knee extension (-15 degrees), right SLR (80 degrees coupled with dorsiflexion), and lumbar flexion (85% coupled with neck flexion) all continued to reproduce right buttock cramping and pain. Currently he is playing basketball without restriction, performing an individualized exercise program that emphasizes lower extremity muscle stretching, AMNT stretching, and advanced truncal stabilization exercises. He has a very good understanding of body mechanics and an awareness of safe SFP during activities of daily living and on the basketball court. His motivation, along with the motivation of parents, coaches, athletic trainer, and physical therapist, greatly assisted CC in returning to competitive basketball. CC is intermittently evaluated to monitor the AMNT sign and the effectiveness of the home exercise program. Currently CC's AMNT appears to regress if he is not monitored on a monthly basis; thus he warrants intermittent treatment. Monitoring of the patient is an integral aspect of long-term management of chronic discogenic disease that is often neglected. It can be hypothesized that monitoring may prevent serious complications in the future for many patients. CC is a patient who needed specific therapeutic intervention beyond rest, general instructions about body mechanics and exercise, modalities, and traditional back school. The history of this patient's problem revealed that rest and general exercises had failed, thus necessitating specific therapeutic treatment. This patient is an excellent example of how physical therapy in the form of manual therapy, specific therapeutic exercise, education through repetition of functional tasks, and the team approach to patient care can lead to a successful treatment outcome.