Closed-loop and strangulating intestinal obstruction: CT signs.

In 19 patients with closed-loop intestinal obstruction, including 16 patients with strangulating obstruction, the findings at examination with computed tomography (CT) were retrospectively correlated with the surgical and pathologic findings and evaluated by two radiologists. Signs of closed-loop obstruction, present in 15 patients, were associated with the configuration of the incarcerated loop of small bowel, abnormalities detected at the site of obstruction, or both. These abnormalities were the following: a U-shaped, distended, fluid-filled bowel loop; the whirl sign; the beak sign; a triangular loop; two adjacent collapsed loops of bowel at the site of obstruction; or all of these. CT signs of strangulation, seen in 10 of the 16 patients with ischemic or infarcted bowel, were associated with the appearance of the bowel wall (thickening, high attenuation, and the target sign), abnormalities in the attached mesentery, or both. In mechanical obstruction of the small bowel, detection of ischemic changes in the bowel wall or mesentery with CT indicates strangulation. Absence of CT findings of ischemia or infarction does not rule out strangulation.

Defective suppression in the autologous mixed lymphocyte reaction in patients with Crohn's disease.

T helper and suppressor cell control of autologous immunoglobulin production was measured in 14 patients with Crohn's disease (CD) using autologous B cells or monocytes to stimulate regulatory T-cell activity. A pronounced defect in suppressor cell function was observed in the patient group but not in matched controls irrespective of whether B cells or monocytes were used as the stimulus. This defect was observed for IgG, A and M. This defect was seen both in patients with active disease and with inactive CD suggesting the possibility that a primary regulatory defect might exist in this disease. The patient group displayed normal helper cell function.

Studies on the interaction between alpha-gliadin and HLA and T cell receptor molecules in coeliac disease.

Coeliac disease has a known strong linkage with the HLA complex and has also recently been linked to the T cell receptor genes but the mechanism whereby these genes confer susceptibility is not known. This study has examined two possible mechanisms: (i) direct, lectin-like binding of alpha-gliadin (the causative agent of CD) to HLA or TcR molecules and (ii) antigenic cross-reactivity between alpha-gliadin and HLA or TcR molecules. A flow cytometer was used to assess interactions between alpha-gliadin, anti-alpha-gliadin antibodies (raised in both coeliac patients and in rabbits) and EBV-transformed B cell lines from coeliac patients and HLA-matched and mismatched normal controls. The B cell lines were shown to express HLA-DP, -DQ and -DR antigens which are also found on coeliac intestinal epithelial cells. After incubating B cell lines with alpha-gliadin over a wide range of concentrations, no binding of alpha-gliadin to any of the cell lines could be detected with either of the gliadin-specific antibodies. This suggests that HLA molecules do not bind to alpha-gliadin in a lectin-like fashion. In contrast to the B cell lines, alpha-gliadin binding to peripheral blood monocytes could be demonstrated. This binding occurred equally to patient and control monocytes and was not influenced by HLA allotype. The second possibility tested was that alpha-gliadin and the disease-associated HLA molecule bear antigenic similarities. However, neither rabbit anti-gliadin serum nor purified human alpha-gliadin antibody bound directly to the B cell lines. Using peripheral blood T cells similar results were obtained; no binding of alpha-gliadin or antibodies to alpha-gliadin was found. Thus this study shows that the HLA and TcR associations with CD are not explained by the direct binding of alpha-gliadin to these molecules nor by a sharing of antigenic determinants between alpha-gliadin and these molecules.

The effect of unilateral experimental testicular torsion on spermatogenesis and fertility.

Significant subfertility exists in patients following unilateral testicular torsion, implying bilateral testicular disease. Immunological activation has been detected after experimental torsion and the present study sought to demonstrate immunologically mediated effects on contralateral spermatogenesis following experimental torsion, as well as quantifying ipsilateral damage. Early and late effects of torsion on bilateral spermatogenesis were studied at 1 and 6 months in 10 groups each containing 20 rats. Gross and histological examination, direct immunofluorescence tests, vas deferens counts and copulation studies were performed. Severe ipsilateral damage was noted, even after brief torsion periods. No contralateral testicular effects, immunological or otherwise, were observed. Ipsilateral damage after torsion may have been underestimated. There is no damage to contralateral testicular exocrine function following unilateral experimental torsion.

Computed tomography of the abnormal appendix.

This report describes the CT features of 29 abnormal appendices visualized during abdominal CT examinations. There were 22 cases of acute appendicitis, five mucoceles, and two mucinous adenocarcinomas of the appendix. The inflammed appendix appeared either as a fluid-filled slightly distended structure or as a collapsed small tubular structure. It was visualized on either cross or longitudinal sections and showed slight circumferential wall thickening. Periappendiceal inflammation was detected in 19 cases and intraluminal appendicoliths in six cases. Mucocele appeared as a larger fluid-filled round, oval, or tubular structure having a thin, sharp wall, low density contents, and no periappendiceal inflammation. Mucinous carcinoma appeared either as a single or as multiloculated, irregular shaped cystic lesion with solid elements. Infiltration of cecum and terminal ileum was seen in one case. In five cases the abnormal appendix was not recognized initially and was identified only after repeat 5 X 5 mm sections were obtained. During CT examination, demonstration of an abnormal appendix establishes the source of the abdominal pathology and helps greatly in the differential diagnosis.

The vas deferens count: a new accurate method for experimental measurement of testicular exocrine function.

Clinical and experimental measurement of fertility presents difficulties in technique and interpretation of results. This study compared a new concept, the vas deferens count (VDC), with the standard electroejaculation method as a means of measuring testicular sperm output. Seventy-five Wistar rats in three groups (control, orchidectomy, torsion) underwent VDC and electroejaculation fertility analyses. The VDC was successful in all cases and gave rise to results showing acceptable variance and, in addition, measured unilateral testicular exocrine function in each case. Electroejaculation was found to be a less satisfactory technique. The VDC is a simple and accurate technique for measuring testicular exocrine function in experimental animals.

Relationship of clinical and immunological abnormalities in haemophilia A to F VIII therapy and HIV exposure: a longitudinal study.

This study was established to examine the longitudinal consequences of F VIII therapy on immune function in 24 patients with haemophilia A. Antibodies to the human immunodeficiency virus (HIV) were found in 15 of 16 patients with severe haemophilia and in 2 of 8 patients with mild disease. The principal clinical and immunological abnormalities were restricted to the HIV antibody-positive patients: T helper cell lymphopenia (less than 0.55 x 10(9)/l) in 10 patients, persistent glandular lymphadenopathy in 4 patients and depressed response to skin recall antigens in 7 of 9 HIV-positive patients tested. Although no extension of these immunological and clinical abnormalities developed in the 18-month period of monitoring, T helper cell counts and platelet counts were significantly lower in a group of patients with established long duration HIV seropositivity (since 1982/1983) in comparison with the remaining seropositive patients. This suggests that a progressive pathological process is associated with infection by this virus, but the factors which determine the long-term sequelae are still unknown.

Fluid within preexisting pulmonary air-spaces: a potential pitfall in the CT differentiation of pleural from parenchymal disease.

There have been many reports of the ability of CT to distinguish between parenchymal and pleural disease. The purpose of this report is to describe the appearance of seven cases of intraparenchymal fluid-filled air-spaces (bullae or lung cysts) in which the CT findings may resemble those of pleural disease and, thus, cast doubt on the specificity of the established criteria.

Removal of endogenous peroxidase activity from cryostat sections for immunoperoxidase visualisation of monoclonal antibodies.

The interpretation of immunoperoxidase staining of frozen tissue sections can be severely limited by the presence of endogenous peroxidase enzymes in the tissue. Previously recommended methods of reducing this enzyme activity were examined, but were found to be unsatisfactory when applied to the small intestine. A method, which effectively eliminates this background staining but which does not interfere with the binding of monoclonal antibodies to various tissue components, is described. This method may prove useful in immunoperoxidase studies of other tissues in which high levels of endogenous peroxidase are present.

Peripheral blood T lymphocyte changes in multiple sclerosis: a marker of disease progression rather than of relapse?

A serial study of peripheral blood T lymphocytes in 27 patients with clinically definite multiple sclerosis and 11 healthy controls was carried out over a 12 month period. This showed that contrary to many previous reports, relapses were not consistently associated with reduced numbers of peripheral blood suppressor T lymphocytes or any other T cells. Persistently low T cells numbers, including both the helper and suppressor T cell subsets, were, however, associated with disease activity as measured by the development of increased disability during the course of the study. This was true both for the patients with relapsing/remitting disease and those with progressive disease. The importance of carrying out a serial study was emphasised by the consistent and significant differences that were detected between individuals in both the control and the patient groups. A serial study is the most reliable means by which clinical events can clearly be correlated with laboratory estimations. The association in this study between the development of increased disability and persistently low levels of peripheral blood T lymphocytes suggest that both may be related to the underlying disease process in multiple sclerosis.

The immunological consequences of gold therapy: a prospective study in patients with rheumatoid arthritis.

Gold sodium thiomalate (GST) is known to modify the disease process in patients with active rheumatoid arthritis (RA). To help understand the mechanism of action of GST, several immunological parameters were prospectively evaluated in 10 patients with active RA following the introduction of gold therapy. Before therapy, absolute numbers of peripheral blood T suppressor/cytotoxic lymphocytes were significantly depressed (P less than 0.01) and a raised T helper/T suppressor cell ratio was found. After 1 g of GST, an absolute reduction in total lymphocyte numbers including HLA/DR positive mononuclear cells, was evident (P less than 0.01). This lymphopenic effect was not selective for a single population since the proportions of T cells, T cell subsets and B cells remained unchanged. Lymphocyte function was also examined. Raised in vitro production of IgG (P less than 0.01) and IgA (P less than 0.05) was found before therapy. After GST, in vitro immunoglobulin synthesis was reduced and this was significant with respect to the IgM (P less than 0.001) and IgA (P less than 0.01) isotypes. Similarly, a parallel reduction in serum immunoglobulin levels developed. GST therapy was also associated with a reduced proliferative response to phytohaemagglutinin, concanavalin A and pokeweed mitogen in the initial phase of gold administration. The significant finding in this study suggest that the in vivo immunosuppressive effect of GST is explained not only by impaired mononuclear cell function but also by a significant reduction in T and B lymphocyte numbers.

Suppressor T cell changes in active multiple sclerosis: analysis with three different monoclonal antibodies.

This study demonstrates a significant reduction in the number of both total T cells and suppressor T cells identified by monoclonal antibodies in multiple sclerosis patients in acute relapse but not in those in remission. The reduction in the number of suppressor T cells was shown by all three monoclonal antibodies used but was most clearly demonstrated using Leu 2a rather than either OKT 8 or OKT 5. These findings suggest that the choice of monoclonal antibody used in a study of suppressor T cell numbers will influence the results and may help explain the lack of agreement in previous studies.

Helper and suppressor T lymphocyte function in severe alcoholic liver disease.

The immune regulatory T cell status of patients with severe alcoholic liver disease (ALD) was investigated. Using monoclonal antibodies to identify lymphocyte subsets in 22 patients, a significant decrease in the percentage of T suppressor/cytotoxic cells (P less than 0.01) and increase in the percentage T helper/inducer population (P less than 0.05) was observed when the results were compared with 20 normal controls. However, when absolute numbers of these lymphocyte subsets were calculated the patient group did not differ significantly from the controls. Further studies revealed T immunoregulatory cell function to be normal. Concanavalin A induced suppressor cells resulted in equivalent inhibition of autologous cell mitogen responsiveness in the patient and control groups. In addition, purified patient T lymphocytes were demonstrated to provide normal help to and manifest normal suppression of IgG, IgA and IgM synthesis by allogeneic B cells. When spontaneous immunoglobulin synthesis by circulating mononuclear cells was investigated, a significant increase in IgA synthesis was found in the ALD patients (P less than 0.05). These results suggest that T cell immunoregulation is normal in patients with ALD and a defect in this system is not responsible for the increased synthesis of immunoglobulin observed in ALD.

Possible in vivo modulation of Leu 2a expression on suppressor T cells in active multiple sclerosis.

Reduced numbers of suppressor T lymphocytes were identified by monoclonal antibodies in the peripheral blood of patients with multiple sclerosis (MS) in acute relapse. In vitro culture of cells from these patients resulted in a significant increase in the number of cells identified with the suppressor T cell marker Leu 2a but not OKT 8. The expression of other T cell antigens (Leu 4 and Leu 3a) remained unchanged. This change in Leu 2a expression did not occur when cells from healthy controls were similarly treated.

Suppressor-cell activity in coeliac disease induced by alpha-gliadin, a dietary antigen.

The wheat protein antigen alpha-gliadin, a fraction derived from gluten of molecular weight 60 000, activated suppressor cells from patients with coeliac disease but not from normal subjects or patients with Crohn's disease. Two other dietary antigens, casein and beta-lactoglobulin, failed to produce suppressor-cell activation. Since this phenomenon appears to be specific to coeliac disease, it may be of pathogenetic significance.