Biomedical subjects
Publications and source records attributed to J Weis.
We describe a technique for simulation and correction of the effects of an arbitrary distribution of undesired components of the static and gradient magnetic fields. This technique is applicable to direct Fourier NMR imaging. The mathematical basis and details of this technique are fully described. Computer simulation demonstrates the effectiveness of this method.
After a short introduction to the topic of psychiatric evaluation research and the problems of vocational reintegration of psychiatric patients the article reviews the latest development in research on vocational integration. The analysis of literature scrutinizes the significance of different predictors concerning sociodemographic status, vocational aspects, status and treatment of mental illness and social relations. The various results are integrated and conclusions for the practice of vocational rehabilitation and further investigation are drawn.
Axonal regeneration through silicone tubes was studied using distal nerve stumps, denervated, preatrophied muscle tissue, as well as fat tissue as a target. During the first stage of regeneration, i.e., within 2-3 weeks after surgery, a thin, filamentous structure consisting of fibrin and connective tissue was seen bridging the gap in all systems. Thereafter, this cord obviously served as a guideline for the outgrowth of increasing numbers of axons into distal nerve stumps as well as into muscle tissue, but not into fat tissue. These findings confirm that preatrophied muscle tissue has a similar "neurotrophic" effect on regenerating nerve fibers as distal nerve stumps. The ineffectivity of fat tissue in promoting nerve fiber regeneration could be attributed either to the absence of "neurotrophic factors" or even to an inhibitory effect.
The effects of streptozotocin-induced (STZ) diabetes on neuroendocrine and sexual function were evaluated in adult male rats. Adult male rats were injected with STZ (50 mg/kg) or vehicle and tested for copulatory behavior 7, 14, and 21 days later. The rats were killed 1 month after STZ or vehicle treatment for measurement of plasma hormone levels, hypothalamic catecholamine turnover, LHRH content, and in vitro pituitary function. The STZ rats showed significant deficits in mount, intromission, and ejaculatory behaviors. Plasma levels of testosterone, LH, FSH, and PRL were all significantly reduced in the STZ compared to the control rats, but in vitro LH secretion was enhanced after STZ treatment. In vitro PRL secretion and the inhibitory response to dopamine did not differ between the two groups. The levels of LHRH were reduced in the medial basal hypothalamus (MBH), but LHRH levels in the median eminence (ME) and anterior hypothalamus (AH) were unchanged after STZ treatment. Norepinephrine turnover was reduced in the ME, MBH, and AH of the STZ rats, while dopamine turnover was unchanged in the ME, increased in the MBH, and reduced in the AH of the STZ rats compared to those in the vehicle-treated controls. These results suggest that changes in pituitary and testicular function in rats made diabetic by STZ treatment are secondary to changes in hypothalamic catecholamine metabolism. Changes in copulatory behavior could be due to both reductions in plasma testosterone levels as well as changes in central neurotransmitter metabolism.
The proximal stumps of transected sciatic nerves were implanted into an abdominal pedicle flap of fat tissue in rats. Nerve stumps that had been transected without implantation into fat tissue served as control experiments. At 4, 8, or 24 weeks postoperatively, the rats were sacrificed and the neuromas at the transected nerve ends together with the adjacent fat tissue were studied after intra-aortal perfusion fixation. Light microscopy revealed no significant difference in neuroma size between the two groups. In most animals with fat implantation, however, infiltration of fat tissue beyond the margins of the solid neuromatous bulb by regenerating nerve fibers was limited to rare axons growing along blood vessels and connective tissue strands. In only a few instances was the fat tissue itself invaded by minifascicles as was usually seen in the connective tissue surrounding control neuromas. It is concluded that diffuse outgrowth of nerve fibers is limited to some extent by fat tissue, which, however, is not an impermeable barrier for regenerating nerve fibers. Nevertheless, in a fat tissue flap, the neuroma is placed in a "soft pressure-free bed" which might be a prerequisite for permanent diminution of pain sensitivity.
The type 2 complement receptor, CR2, a B lymphocyte surface glycoprotein, is known to be a component of the EBV receptor. We now demonstrate that the major EBV outer membrane glycoprotein, gp350/220, is a highly specific ligand for CR2. EBV or beads coated with purified recombinant gp350/220 adsorb to normal B lymphocytes, cap with CR2, become endocytosed into vesicles, and are released into the cytoplasm. This is the first demonstration of herpesvirus glycoprotein-cell glycoprotein receptor interaction in viral adsorption and penetration. The capping of CR2 in response to virus, gp350/220-coated beads, or anti-CR2 monoclonal antibodies is associated with cocapping of surface immunoglobulin. Interaction between CR2 and surface immunoglobulin may be important in modulating the B cell activation that normally follows EBV infection or exposure to antigen.
Hemiatrophia cerebri is a rare disease, and the etiology and pathogenesis remain unclear in most cases. In the present case, the marked hemiatrophy of the brain in a 19-year-old patient who died suddenly is attributed to encephalitis during early childhood and subsequent prolonged seizures.
Peripheral blood cells from patients with aplastic anemia were tested for their ability to release interleukin-2 (IL-2) and colony stimulating activity (CSA) before treatment. IL-2 release--as measured in the mouse thymocyte assay--was abnormally high in 18/34, and abnormally low in 10/34 patients. "Low" release was due to simultaneous release of thymocyte inhibitors. In 18 patients who achieved self-sustaining hemopoiesis after high dose immunosuppressive therapy, excess IL-2 release decreased to low levels (p less than 0.001), and the release of inhibitors disappeared. In contrast, the release of CSA by patient cells--which did not correlate with peripheral blood monocyte counts--either remained high or increased to excessively high values in 24/24 patients tested before and after successful immunosuppressive treatment. Patients with stable hemopoietic grafts after bone marrow transplantation for aplastic anemia, did not release excess CSA. It is concluded that IL-2 and CSA play opposite roles in aplastic anemia. High IL-2 release seems associated with disease activity, whereas high CSA-release appears to reflect a repair mechanism.
Bone marrow from 20 patients with aplastic anaemia at different stages of disease and from three patients with paroxysmal nocturnal haemoglobinuria (PNH) was incubated in isosmolar sucrose with 5% autologous serum prior to culture in methylcellulose. If fresh serum was used, colony formation by granulocyte-macrophage colony forming cells (GM-CFC) and immature erythroid precursors (BFU-E) was reduced to approximately 50% in all patients tested, at any stage of disease, including complete autologous bone marrow recovery. Heat inactivation and complement inactivation with EDTA completely abrogated this inhibitory serum effect. Selective inactivation of the classical, antibody dependent complement pathway with Mg2+ EGTA reduced the inhibitory effect by 50%. Complement sensitivity of haemopoietic precursors is a known feature of PNH. Since the majority of our patients did not have PNH as judged by a negative sucrose-test on mature erythrocytes, we conclude that, in aplastic anaemia, haemopoietic cells express a PNH-like defect at a primitive level.
Unusual cytogenetic findings were noted in the leukemic cells from a patient with congenital acute monocytic leukemia (AMol or M5, according to the FAB classification), whereas, the chromosomes of cultured skin fibroblasts were normal. G-banded karyotypes of leukemic cells showed an X-autosome translocation, 46,X,t(X;10)(Xpter----q13::10q11.2----qter)(10pter---- q11.2::Xq28----q13:: Xq28----qter). Review of reported cases of acute nonlymphocytic leukemia (ANLL) with rearrangements involving chromosomes #10 or X showed a high frequency of abnormalities of the short arm of #10 in myelomonocytic (M4) and monocytic (M5) leukemias, particularly in patients less than 2-yr-of-age. Although previously reported cases of ANLL in infants are predominantly of these types, the translocation observed in this case is unique. Fragile sites known to exist on chromosomes #10 and X are not associated with neoplasia and, except for Xq27-28, were not at the breakpoints of the case presented. The precise location of a human cellular oncogene recently identified on the X chromosome remains unknown.
A case is reported of ethylene oxide polyneuropathy after 5 months of exposure. There was symmetrical distal weakness of both lower extremities and transitory reduced nerve conduction velocities with increased latencies. Sural nerve biopsy revealed nerve fibre degeneration of the Wallerian type, associated with reduction of axonal cross-sectional areas and some degree of nerve fibre regeneration that could be confirmed morphometrically. In addition, there was conspicuous paranodal vesicular disintegration of individual myelin lamellae. Unusual cisternae with introverted hemidesmosomes were noted in endoneurial fibroblasts.
Human serum contains an activity which enhances the release of colony stimulating and burst promoting activity (CSA and BPA). It is low in the majority of normal sera and was found elevated in patients with aplastic anaemia. The patient's 'response' to autologous serum releaser activity was measured by comparing CSA and BPA release by patient cells in percentage of release by normal cells. This 'response' was negatively correlated with serum releaser activity (P = 0.0035 for CSA-release, P less than 0.0001 for BPA-release), i.e. releaser activity was high, when factor release was low. This inverse relationship between releaser activity and the patient's response was also observed in four patients with pancytopenia of causes other than aplastic anaemia. We conclude that elevated serum releaser activity reflects a repair mechanisms which operates when CSA- and BPA-production is inadequate. Thus, releaser activity is likely to be a haemopoietic regulator.
Serum from patients with aplastic anaemia contains two distinct stimulatory activities on haemopoiesis in culture. The first is a highly unstable enhancing activity, which mainly stimulates colony formation from BFU-E and macrophage precursors, and only acts when added directly to target bone marrow cultures. It is destroyed by Sephadex G-150 chromatography, and thus differs from colony stimulating activity (CSA) and burst promoting activity (BPA). Its mode of action is unknown. It was elevated in 70/97 patients with severe aplastic anaemia (SAA). 71 of these 97 patients were treated with high dose immunosuppression. 55/71 who achieved self-sustaining haemopoiesis had higher serum stimulating activity on BFU-E than 16/71 who never achieved remission (P = 0.0004). It was predictive of response as an all or none phenomenon, independent of the time required for recovery. It was, however, unsatisfactory as a single prognostic test. Bone marrow reconstitution also occurred in 4/71 patients whose serum inhibited BFU-E in direct culture. The second stimulator acts via enhancement of CSA- and BPA-release by accessory cells and is therefore termed 'releaser' activity. It was elevated in 27 of 51 aplastic anaemia patients and did not correlate with direct stimulatory activity. High 'releaser' activity was not predictive of response in 42 patients treated with high dose immunosuppression. However, the ability of patient cells to respond to autologous 'releaser' activity was a positive risk factor. Patients whose cells released an excess of CSA in the presence of autologous serum had a significantly higher chance of autologous recovery within 3 months than patients who produced little or no CSA in the presence of normal or excess releaser activity (P less than 0.0001). A scoring system which includes these two good risk factors is proposed for estimation of a patient's probability to recover autologous bone marrow reconstitution.
A novel H-2 gene in which the first external (N) domain of the H-2Ld antigen was replaced with that of the H-2Dd antigen was constructed and introduced into L cells. A transformant expressing the products of the hybrid gene was studied for binding to monoclonal antibodies specific for H-2Ld and H-2Dd antigens. It was found that serological determinants are distributed both in the N (Dd) and Cl (Ld) domains. Determinants recognized by allospecific cytotoxic T lymphocytes (CTLs) and virus-specific CTLs also mapped to the N and Cl domains. Determinants recognized by vesicular stomatitis virus (VSV)-specific effect cells, however, were not present on the recombinant molecule. These results show that a recombinant gene of two H-2 antigens in which the first external domain has been reshuffled can express a functional H-2 antigen that can then be used to map serological and CTL determinants to specific domains.
The immune response genes of the mouse encode two cell-surface glycoproteins, I-A and I-E, that play critical roles in determining the animal's immune responsiveness. The I-A antigen contains two chains, alpha and beta. A cloned beta-chain gene, I-A beta k, was introduced into B-lymphoma cells that express I-Ad. The transfected gene was successfully expressed on the cell surface of the recipient cells and was functional in stimulating allospecific T cells.
Monoclonal antibodies were prepared against the avian myeloblastosis virus reverse transcriptase. These monoclonal antibodies specifically immunoprecipitated the alpha and beta subunits of the reverse transcriptase molecule, as well as the Pr180gag-pol precursor protein present in virus-infected cells. In addition, these monoclonal antibodies inhibited the DNA polymerase activity associated with the reverse transcriptase molecule but not the RNase H activity. The monoclonal antibody preparations were specific for the amino-terminal portion of the protein, as determined by the immunoprecipitation of a reverse transcriptase-beta-galactosidase fusion protein produced in Escherichia coli by molecular cloning procedures.
A new Salmonella serotype (3,10:z:z6) was isolated from a fecal specimen of a lizard (Lacerta viridis) imported from Northern Italy. The strain was accepted as a new Salmonella, Subgenus I, on January 11, 1980, by Prof. Le Minor, International Salmonella Centre Paris. The organism was introduced into the Kauffmann-White-Scheme, Supplement XXIII as S. landwasser in referring to the first isolation in a Veterinary Research Institut in Landwasser, a suburb of Freiburg (FRG).
In a pharmacolinetic study on a new semisynthetic penicillin, alpha-sulfobenzylpenicillin, sulbenicillin, serum level, serum half-life, apparent distribution volume, renal clearance, urinary excretion, and metabolism were determined after a 4-gm intravenous dose and compared to that of carbenicillin in 5 patients with normal renal function. In the case of sulbenicillin, the mean serum concentration at 1 hr was 157 plus or minus 25 mug/ml, the mean serum half-life was 70 plus or minus 10 min, the renal clearance was 95 plus or minus 25 ml/min, and the total urinary recovery after 24 hr was about 80% of the dose. The only metabolite detected in the urine was the penicilloic acid derivative, in an amount usually less than 5% of the dose. Serum values, serum half-live, renal clearances, and excretion pattern did not differ significantly from that of carbenicillin. In 8 patients with decreased renal function (creatinine clearance less than 50 ml/min) there was an inverse correlation between creatinine clearance and serum half-life.