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Biomedical subjects

P Lang

Publications and source records attributed to P Lang.

At least 307 records · Page 17Linked to original sources
PubMed1988

[3-dimensional computed tomography and multiplanar CT-reformations in lumbar spondylodesis].

Three-dimensional computed tomography (3-D-CT) and multiplanar CT reformations were performed in 42 patients who were clinically suspected of spinal instability following posterior lumbar fusion. Sagittal and coronal CT reformations demonstrated fusion pseudarthrosis more frequently than axial CT or conventional radiography. Three-dimensional CT cuts through the fusion revealed pseudarthrosis in most patients with positive 2-D images. In 5 patients, however, fusion appeared to be artifactually stable or unstable on 3-D cuts contrasting the 2-D images. Three-dimensional surface reconstructions demonstrated the complex anatomy of the fusion and showed superficial breaks. They were helpful in preoperative planning as well as intraoperative localization. 3-D-CT is a clinically useful adjunctive imaging method.

Adult↗
PubMed1988

Three-dimensional computed tomography and multiplanar reformations in the assessment of pseudarthrosis in posterior lumbar fusion patients.

Three-dimensional (3-D) surface reconstructions and multiplanar computed tomography (CT) reformations were obtained in 30 patients with clinically suspected spinal fusion pseudarthrosis. The imaging studies were blind-reviewed and the results were compared with the clinical and surgical findings. Sagittal, planar, and curved coronal two-dimensional (2-D) reformations were more useful in the detection of bony nonunion than were axial CT scans, as the latter required more extensive analysis. Three-dimensional surface "cuts" adequately demonstrated pseudarthrosis in most cases. In some instances, however, segmentation artifacts created artifactual clefts or implied solidity, which contrasted with the interpretation of the 2-D images. Sagittal 3-D cuts were helpful in demonstrating bony central and lateral stenosis. Three-dimensional surface reconstructions demonstrated superficial clefts and outlined the complex anatomy of the spinal fusions, thus facilitating pre- and intraoperative planning. The amount of bone stock available for pseudarthrosis repair at the fusion site and the need for additional harvesting of bone from the iliac crest also could be assessed easily. 3-D CT proved to be useful as an adjunctive imaging method in the evaluation of posterior lumbar fusion patients suspected of pseudarthrosis.

Adult↗
PubMed1988

Altered threshold for the induction of graft-versus-host immunodeficiency following murine cytomegalovirus infection. Host and donor contributions.

Acute murine cytomegalovirus (MCMV) infection enhances the ability of parental spleen cells to induce graft-vs.-host immunodeficiency (GVHID) in F1 hybrid mice when the two processes occur simultaneously in the recipient. The present study assessed GVHID as the ability of spleen cells to generate in vitro cytotoxic T lymphocyte responses to trinitrophenyl-modified syngeneic cells. The results indicate that MCMV infection not only reduces the number of parental spleen cells required to induce GVHID, but accelerates the onset of GVHID, which occurs as early as 3 days after cell and virus challenge. To determine whether MCMV infection exerts this synergistic effect primarily through the donor or the host component, we examined the effect of MCMV infection of either donor mice or recipient mice at 3, 10, and 17 days prior to spleen cell transfer. Two weeks after cell transfer, splenocytes were tested for their ability to generate CTL. When donor mice were infected with MCMV three days prior to cell transfer, the ability of donor cells to induce GVHID was reduced. In contrast, MCMV infection of the recipients three days prior to cell transfer increased their susceptibility to GVHID induction. Infection of either donor or host mice 10 days or 17 days prior to parental spleen cell transfer had little effect on the ability to induce or resist GVHID when compared with sham-infected mice. Thus, acute MCMV infection can modulate the severity of GVHID depending on whether it is the donor or the host that is infected. The ability of acute MCMV to alter the course and severity of GVHID may be relevant for human bone marrow transplants in which preceding CMV infection has been associated with chronic GVH. In this setting, CMV may lower the threshold necessary to induce a GVH reaction.

Animals↗
PubMed1988

Avascular necrosis of the femoral head: high-field-strength MR imaging with histologic correlation.

Magnetic resonance (MR) images, contact radiographs, and histologic sections of six femoral head specimens with avascular necrosis were correlated. A low-signal-intensity band or ring represented the repair tissue interface surrounding a high-signal-intensity necrotic marrow segment. Large segmental areas of low signal intensity were observed on T1-weighted images when the lesion consisted of necrotic bone with amorphous marrow debris and adjacent thickened trabecular bone with mesenchymal repair tissue infiltration. On intermediate-weighted images, however, mesenchymal repair tissue, which was located inferior to the necrotic zone, increased markedly in signal intensity, permitting distinction from low-intensity necrotic bone with amorphous marrow debris. When trabecular thickening with collapse predominated, segmental areas of low signal intensity with both sequences were found. MR signal intensities used in combination with anatomic configuration and location may provide information of potential therapeutic importance regarding tissue composition and stage of disease.

Adult↗
PubMed1988

Open repair of cardiac defects in neonates and young infants.

This article provides a general description of many aspects of the perioperative and operative management of neonates and young infants with congenital heart disease. Operative technique and results are described in more detail for the most important defects.

Alprostadil↗
PubMed1988

[Idiopathic nephrotic syndrome and food hypersensitivity. Value of an exclusion diet].

A case of idiopathic nephrotic syndrome (INS) evolving since more than 7 years with 4 successive corticosensitive relapses is reported. At the time of a 5th relapse corticosteroid treatment was refused by the parents and evolution went on without any spontaneous tendency to remission. Three months later, allergy tests detected various sensitizations, especially for food allergens. An antiallergic treatment including dietary exclusions induced a complete and durable remission. Five similar cases are reported. These facts, compared to data from the literature, indicate the possible role of food hypersensitivity in INS. Its mechanism has been discussed; the possible part of a lymphocyte activation has been emphasized.

Adrenal Cortex Hormones↗
PubMed1988

Distribution of cyclosporin A between blood cells and plasma of cardiac and renal transplant recipients.

The relationship between blood cells and plasma concentrations of cyclosporin A (Cy A) determined by radioimmunoassay, was investigated in 12 heart and 12 kidney transplant recipients. The decision between a linear and nonlinear model was made according to a standardized residuals plot. We observed high blood cells-plasma concentration ratios in the two groups, indicating a high affinity of Cy A for blood cells. The distribution of Cy A between blood cells and plasma was ascribed to a nonlinear saturable model in the two groups. According to our results we have simulated the blood-plasma concentration ratio of Cy A as a function of plasma Cy A concentration and hematocrit.

Adolescent↗
PubMed1987

Management of xeroderma pigmentosum.

Xeroderma pigmentosum is an autosomal recessive disease associated with a defect in DNA repair from damage by ultraviolet light. It is characterized by the development of cutaneous malignancies in childhood and by death from the local or systemic complications thereof by the third decade of life. The head and the neck are the most frequently affected areas. Management involves sunlight avoidance and prompt biopsy of any new skin lesion. Due to the chronic nature of the disease, it is necessary to excise the least amount of tissue consistent with tumor removal in order to preserve skin for future procedures. In some patients, radiation therapy and/or certain chemotherapeutic agents are abnormally cytotoxic and must be utilized with caution.

Head and Neck Neoplasms↗
PubMed1987

Accuracy of subcostal two-dimensional echocardiography in prospective diagnosis of total anomalous pulmonary venous connection.

Since reparative surgery without cardiac catheterization has been advocated for certain lesions such as total anomalous pulmonary venous connection (TAPVC), it is important to assess the accuracy of two-dimensional (2-D) echocardiography in the prospective diagnosis of this lesion. Abandoning traditional cardiac catheterization and angiography would be justified only if all surgically relevant anatomic features could be consistently displayed noninvasively. Consequently, we reviewed our experience with TAPVC to determine the suitability of subcostal 2-D echocardiography as the sole prospective diagnostic tool. Over a 5-year period, of 2444 infants under 2 years of age who underwent subcostal 2-D echocardiography, 38 were diagnosed as having TAPVC as the only major cardiac defect. There were no false-negative or false-positive cases during the time of the study. Drainage sites were diagnosed correctly in 36 (95%). Of the five cases of mixed-type TAPVC, the second drainage site was missed by 2-D echocardiography in two cases.

Echocardiography↗
PubMed1987

Surgical management of subaortic obstruction in single left ventricle and tricuspid atresia.

Subaortic obstruction caused by either a restrictive bulboventricular foramen in single left ventricle with an outflow chamber or by a restrictive ventricular septal defect in tricuspid atresia with transposition of the great arteries can lead to a hypertrophied, noncompliant ventricle and excessive pulmonary blood flow. This combination is disadvantageous to potential Fontan procedure candidates because they are dependent on good ventricular function and low pulmonary vascular resistance for survival. The results of surgical procedures to directly or indirectly relieve significant subaortic obstruction (gradient greater than 30 mm Hg) in 24 patients, 16 with single left ventricle and 8 with tricuspid atresia, were reviewed. Four patients had a left ventricular apex to descending aorta valved conduit; none survived. Seven patients had resection of subaortic tissue; four survived and four developed heart block at surgery. Adequate gradient relief was evident in only one of the four survivors. Thirteen patients had a main pulmonary artery to ascending aorta anastomosis or conduit; six survived. All survivors had adequate gradient relief. The overall survival was 42% (10 of 24). None of seven patients with a subaortic gradient greater than 75 mm Hg survived. These data show that: Surgical relief of established subaortic obstruction in patients with single left ventricle and tricuspid atresia carries a high mortality rate, especially if the subaortic gradient is greater than 75 mm Hg. The best procedure appears to be the pulmonary artery to ascending aorta anastomosis. A clearer understanding of the factors leading to the development of significant subaortic obstruction is necessary to prevent it or to devise improved therapeutic strategies.

Adolescent↗
PubMed1987

[Magnetic resonance tomography in the determination of the functional stability of posterolateral lumbar spondylodeses].

MR tomography was used to assess functional lumbar stability in 30 patients with posterolateral fusions. The vertebral bodies of 9 of the 12 patients with unstable lumbar fusions presented with areas of decreased signal intensity on T1- and intermediately weighted images, which increased on T2-weighting. The vertebrae of 15 of the 18 patients with stable fusions demonstrated zones of increased signal intensity on T1- and intermediately weighted images, which were less intense or invisible on T2-weighing. Surgical correlation was available in 11 of the 30 patients studied. Hyperemia and inflammation appear to be responsible for the abnormal signal intensities in the patients with stable fusions, whereas an increase in adipose marrow due to decreased biomechanical stress is thought to account for the atypical signal intensities in the vertebral bodies of the patients with stable fusions. MR tomography seems to be a potential method for evaluating functional lumbar fusion stability. MR tomography may be particularly helpful in those patients with multiple back surgeries and possible instability, recurrent disc herniation, or postoperative fibrosis. MR is recommended in the patient, who appears clinically unstable, whose radiographs and CT, however, do not demonstrate fusion failure.

Adult↗
PubMed1987

Phenotypic composition and in vitro functional capacities of unmodified fresh cells infiltrating acutely rejected human kidney allografts.

Cell surface markers of isolated graft-infiltrating cells (GIC) were studied, and functional in vitro assays performed in 8 cases of acute irreversible rejection of human renal allografts. The GIC were mostly activated T cells (OKT11+, OKT3+, Ia+), with predominance of the cytotoxic/suppressor T cell phenotype (OKT8+). A small proportion of B cells and monocytes/macrophages were also present among these GIC. The GIC were able to proliferate with lectin of allogeneic stimulation and were strongly cytotoxic toward specific donor target cells. Within the T cell subset, OKT8+ cells displayed most of the specific cytotoxicity. Despite allograft morphology typical of cellular rejection, anti-HLA complement-dependent antibodies and antibody-dependent cell cytotoxicity were found in the eluted material from rejecting kidneys. The results of our phenotypic and functional testing of unmodified GIC (no enzyme treatment, no additional culture with or without interleukin 2), show that T cells, especially OKT8+ cells, are of paramount importance in the mechanism of this type of acute irreversible rejection of human renal allografts (i.e., to the point of allograft rupture), but other potential effector mechanisms are also present in situ.

Antigens, Surface↗
PubMed1987

Childhood systemic-pulmonary shunts: subsequent suitability for Fontan operation.

We investigated whether or not a systemic arteriopulmonary shunt (SAPS) after 1 year of age affects a child's chances for a successful Fontan procedure. From 1967 to 1986, 50 patients more than 1 year old with tricuspid atresia or other complex lesions amenable to a Fontan operation received a SAPS. Follow-up was incomplete in six patients. Two patients died within 1 week of surgery, and two died within 9 months for a total mortality of 8%. Each of the 40 remaining patients was catheterized 6 months to 10.8 years (mean 4.9 years) after placement of a SAPS. By the criteria of Choussat and Fontan, there were one or more adverse SAPS-induced changes in nine patients (23%). Three developed pulmonary hypertension, one with associated elevation of pulmonary arteriolar resistance and pulmonary artery distortion, and one in conjunction with severe congestive heart failure. Six additional patients developed isolated distortion of the ipsilateral pulmonary artery. Of these nine patients, three had successful Fontan operations (33%), two died after the Fontan operation, and four are no longer candidates. In contrast, of 31 patients without documented SAPS-induced complications, 27 have undergone Fontan operations, 23 successfully (74%). Palliation with a SAPS after 1 year of age can place children at increased risk for a subsequent Fontan operation.

Age Factors↗
PubMed1987

[Combined effect of cytomegalovirus infection and allo-immunization on the cytotoxic T lymphocyte response in the mouse].

We have investigated the reciprocal influence of CMV infection and allo-immunisation on the CTL response of mice against allogeneic cells and TNP modified syngeneic cells. The data show that allo-immunisation regulates the immunological modifications brought about by CMV infection; allo-immunisation impedes the increased reactivity induced by CMV and counters the suppression induced by CMV when the mice are tested against a non specific target, whereas CMV induced immunosuppression persists against the specific immunizing antigen. Reciprocally CMV infection modulates the effect of all-immunisation: whatever may be the effect of CMV infection, the allo-suppression persists against the specific target, whereas it is abolished against a non specific one. We conclude that there is an immune interaction between CMV infection and allo-immunisation which might have clinical implications.

Animals↗