Back support mechanisms during manual lifting

The ability of individuals to lift heavy loads without injury to the vertebral elements has led to the formulation of several explanations of this phenomenon. In this article, the existing literature on lifting is reviewed and mechanisms of back support during lifting are described. These mechanisms include the intra-abdominal pressure mechanism, the thoracolumbar fascia mechanism, and combinations of these mechanisms with the use of the erector spinae, multifidus, and psoas muscles. Physical therapists are often responsible for teaching patients and workers "proper" lifting techniques; however, controversy exists concerning the proper lift. Although lifting with the lower back in flexion and lifting in extension have been proposed, there are indications for each depending on individual circumstances. Lifting instructions for workers without low back injuries should be distinguished from instructions for patients with low back pain. General rules for lifting include: plan the lift, avoid twisting, keep the load close to the body, and bend at the knees.     

Morphology and function of lacrimal gland acinar cells in primary culture

The objectives of the current investigation were fourfold: (1) to establish an effective procedure for the isolation of acinar cells from the rat lacrimal gland; (2) to evaluate the functional capacity of freshly isolated cells; (3) to determine defined culture conditions which permit maintenance of viable, differentiated cells, as well as secretory component (SC) production, during long-term culture; and (4) to characterize the morphological features of cultured cells. Acinar cells were isolated by serial incubation of gland fragments in chelating and enzymatic solutions, followed by centrifugation through a Ficoll gradient. The yield of viable cells/gland appeared to be age-dependent: cell recovery was inversely proportional to the age of the animals. Immunofluorescence analysis of freshly isolated cells showed the presence of SC, the IgA antibody receptor, within isolated cells. In addition, experiments with a labeled analog (Nle4-D-Phe7-alpha MSH) of alpha-melanocyte-stimulating hormone (alpha-MSH) demonstrated specific binding sites on freshly isolated cells; alpha-MSH is a known modulator of acinar protein secretion. Maximum binding of the alpha-MSH analog occurred within 30 min, was dependent upon cell density and was reduced by coincubation with unlabeled alpha-MSH. To determine the culture requirements of acinar cells, cells were cultured on a variety of substrates (plastic or modified plastic [Primaria], coated with or without extracellular matrix [Matrigel]) in the presence or absence of various supplements and/or fetal calf serum (FCS) for 0.7 to 3.5 weeks. Cell attachment, function and long-term viability required an extracellular matrix. Moreover, in long term cultures (25 days), acinar cell attachment was enhanced by the inclusion of supplements to media containing 10% FCS. Replacement of serum with fibroblast growth factor, high-density lipoprotein and an increased concentration of epidermal growth factor resulted in a distinct "cobblestone" morphology characteristic of epithelial cell cultures. Electron microscopic analysis of cells cultured in supplemented serum-free media demonstrated extensive rough endoplasmic reticulum and Golgi, intermediate filaments and numerous secretory granules, as well as tight junctions and desmosomes. In addition to cell maintenance and attachment, acinar cell synthesis and/or secretion of SC was positively influenced by inclusion of supplements in the media. In summary, we have isolated lacrimal gland acinar cells, which express receptors for IgA antibodies and alpha-MSH. In addition, we have defined culture conditions which permit the long-term maintenance of SC-secreting acinar cells.     

Interaction of Leishmania donovani Promastigotes with Human Phagocytes

Leishmania donovani is an important intracellular protozoal pathogen of humans, which resides solely within mononuclear phagocytes. Phase-contrast microscopy and cinemicroscopy were used to examine the interaction of L. donovani promastigotes with human phagocytes to characterize and quantitate the sequence of events that results in leishmanial infection.     

Direct ultrastructural evidence of target-directed polarization by cytotoxic lymphocytes in lesions of human graft-vs-host disease

Cytotoxic lymphocytes are thought to kill target cells by means of potent cytotoxic granules that congregate near the microtubular organizing center and the Golgi apparatus at one pole of the killer cell. We searched for evidence of this type of polarization in 12 lip biopsy specimens from patients with acute and/or chronic graft-vs-host disease (GVHD) compared with two lip specimens from normal individuals. Lymphocytes with such polarization were found in contact with epithelial cells of the squamous mucosa in all 12 cases of GVHD, and cells of the cuboidal minor salivary duct epithelium were found in two of 11 evaluable cases. The data add support to the hypothesis that cytolytic lymphocytes attack epithelial cells in GVHD.     

Managing pain: The Challenge in Underserved Populations: Appropriate Use Versus Abuse and Diversion

ISSUE: Inadequate pain management is a serious public health problem that affects a wide cross-section of Americans. Patients are often denied sufficient medication, because physicians lack training and fear scrutiny from federal and state regulatory agencies. In addition, even the state-financed system of care, Medicaid, has been increasingly denying payment for the best treatment for pain management. These factors are complicated by physician bias about various subgroups and poor physician-patient communication. Comprehensive patient assessment plays a crucial role in determining appropriate treatment and identifying potential abuse problems. Physicians must routinely document medications analgesic effects and screen for potential ill effects and drug abuse. OBJECTIVE: To examine the prevalence of the undertreatment of pain, particularly among African Americans, and to recommend relevant proactive policy and practice changes to aid in eliminating this health problem. CONSENSUS PROCESS: In July 2002, the NMA convened the "Managing Pain: The Challenge in Underserved Populations: Appropriate Use versus Abuse and Diversion" Consensus Meeting in Washington, DC. The country's most renowned experts in the area of pain management and substance abuse reviewed substantial information regarding pain management and substance abuse including the following: --A draft summary paper on pain management and substance abuse that served as briefing material for consensus members; --Annotated bibliographies; --Articles on pain management and substance abuse; and --Key presentations on pain management and substance abuse.     

A factor shed by lymphoblastoid cell lines of HLA-B27 positive patients with ankylosing spondylitis, specifically modifies the cells of HLA-B27 positive normal individuals.

Epstein-Barr virus transformed lymphoblastoid cell lines from HLA-B27 positive individuals with ankylosing spondylitis (B27+AS+) release, into the culture medium, a factor capable of specifically modifying the HLA-B27 positive lymphocytes of normal individuals (B27+AS-); this modification results in a phenotypic change similar to that seen on B27+AS+ lymphocytes. This lymphoblastoid cell line derived factor appears to be physically and functionally similar to a factor present in the culture filtrate of certain Klebsiella isolates. Biogel P-100 chromatography of the material released from the cell line indicated a mol.wt of 25,000-30,000, similar to that of the Klebsiella derived factor. Chromatofocusing on a PBE 94 column revealed that cell line derived factor had an isoelectric point of 5.5 (cf. pI 5.4 for the Klebsiella derived factor). Immunoadsorption experiments suggest that the factor from the B27+AS+ cell line shares antigenic determinants with a cell surface component present on certain Klebsiella isolates. These results will form the basis for future studies on the nature of the interaction between HLA-B27 and certain enteric organisms and their products. A better understanding of this association should elucidate some of the early events in the pathogenesis of the seronegative arthropathies.     

Differential Effects of Clostridium difficile Toxins on Tissue-Cultured Cells

Two immunologically distinct Clostridium difficile toxins elicited similar morphological changes on cultured cells, although there were differences in both toxin potency and cell sensitivities.     

Ribosomal binding sites on poliovirus RNA

Eucaryotic ribosome binding sites on type 1 poliovirus RNA were obtained by isolation of T1 RNase-resistant RNA fragments from 80 S ribosomes that had been bound under conditions specific for initiation of translation and prevented from translocation with sparsomycin. The fragments were analyzed by two-dimensional polyacrylamide gel electrophoresis. Three ribosome-protected (RP) oligonucleotides and several non-ribosomal-protein-protected (NP) oligonucletides were analyzed. Secondary T1 digestion of the RP fragments revealed that at least three separate species existed. By comparison of these secondary digests to T1 digests of RNaseIII fragments mapped on the polio RNA, and by electron microscopic observation of ribosomes bound to polio RNA, preferred ribosome binding sites were localized to near 115 bases from the 5′ end, just to the 3′ side of midgenome, and 780 bases from the 3′ end.     

Heterotopic heart transplants in Biomphalaria glabrata (mollusca: pulmonata). Fate of congeneric xenografts

Hearts were implanted heterotopically into the hemocoel of NIH albino Biomphalaria glabrata from three xenogeneic donor snails, including two New World (B. obstructa, B. tenagophila) and one Old World (B. alexandrina) species, as well as from wild type allogeneic donors. Recipients were examined histologically at 1, 3, 7, 10, 15, 30, 60, 120, and 180 days postimplantation (PI). Grafts from all four donor species were temporarily infiltrated by recipient hemocytes at early intervals PI and in most instances also became encapsulated. Furthermore, the grafts subsequently showed histopathological alterations and abnormal heartbeat relative to preimplantation controls. However, hemocytic reactions eventually subsided, the implants remained structurally intact, and implant myocardial cells both maintained high levels of intracellular glycogen and continued to contract rhythmically for 6 months. No major differences occurred in fates among different xenografts, or between xenografts and allografts. Our observations of prolonged xenograft survival differ from those of previous investigators, most of whom have reported rapid destruction of implanted xenogeneic tissues in molluscs.