[Liver damage from organic solvents].
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Biomedical subjects
Publications and source records attributed to C Kuhn.
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Hepatitis B virus (HBV) contains a particle-associated DNA polymerase/reverse transcriptase activity encoded by the P (pol) open reading frame. Due to its low abundance, the corresponding protein has so far escaped direct detection and structural analysis. As a first step to overcome these difficulties, a series of recombinant vaccinia viruses was constructed and used for the synthesis in human hepatoma cells of both the authentic full length protein and of its functional domains. Pulse chase experiments demonstrated that the P-proteins had very short half lives in striking contrast to the viral core protein expressed in parallel with the same system. No evidence was obtained for a specific proteolytic processing of the P-protein as occurring with retroviral pol gene products. Overexpression of P-protein by recombinant vaccinia viruses was then employed to develop a highly sensitive detection method based on the in vitro phosphorylation of newly introduced target sites for protein kinase A. The usefulness of this method was demonstrated in the analysis of encapsidated P-gene products that were transiently expressed from an appropriately modified HBV genome. The results obtained indicate that the P-protein acts unprocessed, at least during the initial steps of nucleocapsid assembly and reverse transcription, and that a fraction of the P-protein molecules is linked as such to the viral DNA. Direct detection of the hepadnaviral P-protein by in vitro phosphorylation should greatly facilitate future analyses on P-protein structure and function.
We report a case in a neonate of concurrent bronchial atresia and bronchogenic cyst. An accurate, noninvasive, preoperative diagnosis of this unusual combination of anomalies was made by ultrafast computed tomography (UFCT). This case supports the hypothesis that bronchial atresia results from an event occurring in the 5th-6th week of embryological development, rather than after the 16th week as previously believed.
Rats were pretreated with 40 mg/kg/day cocaine for 14 days by either subcutaneous injections or osmotic minipumps. Rats were then withdrawn from the pretreatment regime for 1 or 7 days and given a 20-mg/kg IP cocaine challenge (day 1) or a 0-, 10-, 20-, or 40-mg/kg IP cocaine challenge (day 7). The results indicate that rats receiving intermittent, daily injections exhibited sensitization to the behavioral effects of a cocaine challenge on days 1 and 7 of withdrawal. In contrast, rats receiving continuous cocaine exhibited tolerance to the behavioral effects of a cocaine challenge on days 1 and 7 of withdrawal. The present results support and extend previous research that indicates that the route and temporal pattern of administration influences the effects of chronic cocaine. Furthermore, the present results indicate that the continuous infusion paradigm may represent an alternative animal model of some aspects of high-dose cocaine abuse, as compared to the typical procedure of single, or multiple, daily cocaine injections.
A 30-minute back massage was given daily for a 5-day period to 52 hospitalized depressed and adjustment disorder children and adolescents. Compared with a control group who viewed relaxing videotapes, the massaged subjects were less depressed and anxious and had lower saliva cortisol levels after the massage. In addition, nurses rated the subjects as being less anxious and more cooperative on the last day of the study, and nighttime sleep increased over this period. Finally, urinary cortisol and norepinephrine levels decreased, but only for the depressed subjects.
The immediate effects of relaxation therapy (RT) were assessed in 40 hospitalized children and adolescents with diagnoses of adjustment disorder and depression. These effects were assessed using a within subjects pre-test/post-test design and by comparison with a control group of 20 depressed and adjustment disorder patients who watched a 1-h relaxing videotape. The 1-h RT class consisted of yoga exercise, a brief massage and progressive muscle relaxation. Decreases were noted in both self-reported anxiety and in anxious behavior and fidgeting as well as increases in positive affect in the RT but not the video group. In addition, adjustment disorder patients and a third of the depressed patients showed decreases in cortisol levels following RT, while no changes were noted in the video group. Thus, both diagnostic groups appeared to benefit from the RT class.
Articular cartilage, obtained from the large toe during hallux valgus operations in 37 patients, was investigated for the presence of amyloid by using the Congo red staining method. Amyloid deposits were demonstrated, particularly in the superficial layer of the cartilage, in 30 cases. This amyloid did not react immunohistochemically with any of the antibodies against the known five major amyloid types (AA, A lambda, A kappa, AF, AB). From these data it is concluded that hyaline cartilage in older individuals is prone to infiltration by an amyloid of a hitherto unidentified class. From the morphological observations there seems to be no correlation between amyloid deposits and the development of osteoarthrosis.
Corticotropin releasing factor (CRF) both stimulates ACTH secretion from the pituitary and inhibits secretion of growth hormone (GH) in adult rats through actions in the CNS. The purpose of the present study was to evaluate these pituitary and central actions of CRF in neonatal rats, in which the hypothalamo- pituitary adrenal (HPA) axis is relatively hypo-functional. The results of this study show that central or peripheral administration of CRF evokes a marked dose-related rise in serum corticosterone in 6-day old rats. The same doses of CRF stimulate, rather than inhibit GH secretion. These results suggest that CRF has unique central actions early in ontogeny.
The gene Mst87F is exclusively expressed in the male germ line and is subject to translational regulation. The Mst87F mRNA is transcribed in the primary spermatocytes, stored for three days and then subsequently translated in the post-elongation period of spermiogenesis. Here we report on the isolation of a cluster of four small genes closely related in structure and function to Mst87F. These genes are located at polytene band 84D on the right arm of chromosome three and are named Mst84Da, Mst84Db, Mst84Dc and Mst84Dd. All four genes encode putative proteins composed primarily of a repetitive motif of cysteine-glycine-proline. The genes are exclusively expressed in the male germ line. The poly(A) tail of the Mst84D mRNAs increases in length at day three of pupal development, the time at which a similar change in Mst87F mRNA and translation has been shown to begin. In addition we have identified a conserved 12 base pair element within the 5' untranslated region (UTR) of each gene which is also found at an identical position in Mst87F and which has been demonstrated to be the structural element for translational control of Mst87F expression (Schäfer et al., 1990 EMBO J. 9, 4519-4525). We have mapped the gene cluster to a small deletion associated with a rotund mutation at 84D. Although flies with a homozygous deletion of the cluster still produce motile sperm, electron microscopic examination revealed numerous malformations in the ultrastructure of the axoneme resulting in a drastic reduction of motile sperm.
We compared regional measurements of the pulmonary transcapillary escape rate (rPTCER) for 68Ga-transferrin, obtained by positron emission tomography (PET), with morphometric data obtained from corresponding tissue samples in six anesthetized mechanically ventilated dogs, 1 h after oleic acid administration to either the left caudal lobe (0.015 ml/kg; Lobar group, n = 3) or the right atrium (0.08 ml/kg; Diffuse group, n = 3). Data were obtained from 48 regions in both injured and control lobes (right caudal lobes from the Lobar group). The volume density of edematous or hemorrhagic alveoli at the light-microscopic level was directly related to rPTCER (r = 0.82 for regions with rPTCER values less than 700 x 10(-4) min-1). Likewise, the relative surface of abnormal capillary endothelium and alveolar epithelium at the electron-microscopic level correlated well with rPTCER (r = 0.87 for regions with rPTCER less than 1,200 X 10(-4) min-1). We conclude that the rPTCER measurements obtained with PET reflect the morphological heterogeneity present in oleic acid-damaged lung tissue. Thus rPTCER measurements should be useful as a noninvasive quantitative index of lung injury. Furthermore, the tomographic image display of rPTCER may allow PET to be used as a "physiological probe" to guide tissue excision for later histological evaluation when lung injury is heterogeneous.
Primary pulmonary hypertension is usually considered a disease of younger adults. We reviewed the natural course of primary pulmonary hypertension in patients aged 65 years or greater. During an 8-year period, 63 elderly patients were discharged from our hospital with a diagnosis of pulmonary hypertension. In eight instances, an elevated mean pulmonary arterial pressure (greater than 25 mm Hg) could not be explained by secondary causes. These elderly patients with primary pulmonary hypertension had symptoms common to younger patients with this disease, including dyspnea (eight patients), chest pain (five), pedal edema (four), and fatigue (one). In all but one patient, the initial diagnosis was incorrect, and the patients were thought to have more common diseases of the elderly that cause similar symptoms. Coexisting medical problems were common and further obscured the correct diagnosis. Survival was significantly shorter in those patients with symptoms of less than 6 months' duration. Primary pulmonary hypertension should be considered in the differential diagnosis in elderly patients with unexplained dyspnea and chest pain.
The goal of this chapter is to indicate potential endocrine targets of perinatal drug exposure, to describe the methodologic issues involved in detecting changes in hormone secretion, and to provide examples of several endocrine systems in which exposure to drugs during development significantly impaired normal endocrine development. Finally, we attempted to show that endocrine function is both a target and useful marker for detecting effects of drug of abuse on development that provides the advantages of accurate quantitation and relative response stability across ontogeny.
A new monoclonal antibody Ki-M1P that is raised against supernatants of detergent solubilized human lymph node tissue is described. Ki-M1P recognizes in particular monocytes and their macrophage derivatives as tested by light- and electron-microscopic immunohistochemistry. Granulocytes, dendritic cells as the accessory cells of humoral and cellular immune response, and epithelial, endothelial, neural, and mesenchymal cells do not react with Ki-M1P. In extensive application Ki-M1P has proven to be a useful marker for distinguishing monocytic leukemias within FAB groups M4 and M5. The recognized antigen is composed of five proteins with molecular masses of about 60, 92, 98, 124, and 150 kDa in blood monocytes, whereas tissue macrophages tested so far expressed only the 60-kDa protein. Because the Ki-M1P antigen is not destroyed or masked during routine fixation and paraffin embedding of biopsy tissue samples, Ki-M1P represents a useful diagnostic reagent for the identification of physiological functional and pathologic reaction forms as well as neoplastic variants of the human monocyte/macrophage system even in retrospective studies.
The human hepatitis B viral (HBV) genome contains a conserved open reading frame known as the X-gene which is capable of encoding a polypeptide of 16.565 kDa. The corresponding protein has so far not been identified directly in HBV-infected cells, but in transient transfection assays the X-gene encodes a product that functions as a transcriptional transactivator. To characterize the subcellular distribution, stability and post-translational modifications of X-protein in human hepatoma HepG2 cells, we have established a vaccinia virus expression system. As the major X-gene product, a protein with an apparent molecular weight of 16 kDa, and reacting with an X-protein-specific antiserum, was expressed from recombinant vaccinia virus. In indirect immunofluorescence assay, X-protein appeared to be distributed throughout the cells, with a tendency to localize at the nuclear periphery and to accumulate in granules as its levels increased. By subcellular fractionation, we found about one-third of X-protein associated with the fraction defined as the nuclear framework. In pulse-chase experiments, X-protein decayed with a bimodal half-life of 15 min and 3 h. X-protein having a half-life of about 15 min was found associated with the Triton X-100 detergent-soluble fraction of HepG2 cells, while that associated with the insoluble fraction turned over more slowly. By metabolic labeling with [32P] orthophosphate, we show that X-protein is capable of being phosphorylated. Modification by phosphorylation could play an important role in the regulation of X-protein function.
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The synthesis of collagen and EIIIA-containing cellular fibronectin in certain forms of pulmonary fibrosis occurs in discrete locations: in the Masson bodies in bronchiolitis obliterans with organizing pneumonia and in focal clusters of fibroblasts (fibroblastic foci) within airspaces in usual interstitial pneumonia. These sites were examined by electron microscopy and immunohistochemistry using antibodies against cytoskeletal markers and extracellular matrix components in biopsies from three patients with bronchiolitis obliterans with organizing pneumonia and four patients with usual interstitial pneumonia. Fibroblasts of both Masson bodies and fibroblastic foci expressed vimentin and alpha smooth muscle actin but not desmin, distinguishing them from true smooth muscle. In both structures fibroblasts with well-formed actin filament bundles were aligned parallel to one another, enmeshed in a matrix of fibronectin-containing fibrils (microtendons) that linked cells and collagen bundles. Similar features characterize the phase of contraction during the healing of skin wounds. This suggests that active contractions of fibroblasts plays a role in the remodeling of the lung in pulmonary fibrosis.
Asymptomatic thoracic lymphadenopathy was incidentally discovered in three patients with no definitive diagnoses. Enlarged lymph nodes, removed at thoracotomy, had irregularly distributed, pleomorphic, malignant-appearing cells. Mitoses were frequent. Electron microscopy showed tonofilament bundles and desmosomes. By immunocytochemistry, these cells uniformly expressed desmoplakin and cytokeratins 8 and 18 and various patterns of coexpression with other cytokeratins. One patient had lymphadenectomy, segmental lung resection and radiotherapy; the second had lymphadenectomy and later a lymphadenectomy with pneumonectomy; and the third had lymphadenectomy and radiotherapy. Neoplastic cells were detected exclusively within thoracic lymph nodes. The patients are well 111, 39 and 13 months after initial presentation. The clinical course and the patterns of intranodal distribution and marker expression of the neoplastic cells are unusual and distinct from most carcinomas metastatic to lymph nodes and reminiscent of "lymphoepithelioma-like carcinomas" described in the thymus and other sites. While the malignant cells may reflect metastases from as yet occult primaries or malignantly transformed ectopic epithelial nests, these tumours may arise by transformation from the cytokeratin-positive "extrafollicular reticulum cells" indigenous to lymphoid organs.
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