Development of substance P, Leu-enkephalin and serotonin profiles in the lateral geniculate nuclear complex of albino rat

Immunohistochemical studies for analysing the development of the profile of two peptides--substance P (SP) and Leu-enkephalin (Leu-ENK), and serotonin (SER)--have been conducted on the lateral geniculate nuclear (LGN) complex of albino rats at gestation day 18 and various postnatal age periods. SP immunoreactivity is found to increase from 1 day postnatal (DPN) up to 20 DPN and decrease thereafter, whereas the SER and Leu-ENK-immunoreactive fibres and terminals seen as occasional fibres at 1, 5, and 10 DPN are better visualized from 20 DPN and gradually increase up to 40 DPN. The possible role and significance of the changes seen in these putative neurotransmitters/neuromodulators with development are discussed.

Isotype switching of an immunoglobulin heavy chain transgene occurs by DNA recombination between different chromosomes

Transgenic mice carrying an immunoglobulin mu heavy chain transgene exhibit isotype switching of the transgene. We have now characterized the mechanism of transgene switching in these mice. The site of mu transgene insertion in one transgenic line has been localized to chromosome 5 using a series of polymorphic endogenous retroviruses as genetic markers in backcross mice. The endogenous immunoglobulin heavy chain locus resides on mouse chromosome 12, which shows that transgene isotype switching can occur between two different chromosomes even though normal antibody gene switching has generally been thought to occur within one chromosome. We find that transgene isotype switching involves interchromosomal DNA recombination, and our data suggest that the same enzymatic mechanisms mediate both normal isotype switch recombination and interchromosomal transgene switching. Our findings also support the notion that the isotype switching mechanism can induce chromosomal translocations such as observed for the c-myc gene in some B cell tumors.

Repeat infusion of recombinant tissue-type plasminogen activator in patients with acute myocardial infarction and early recurrent myocardial ischemia

When conventional treatment of patients with early clinical reinfarction after thrombolytic therapy fails, mechanical revascularization may be attempted. An alternative strategy, repeat thrombolytic infusions, is reported. Fifty-two patients with acute myocardial infarction were treated with one or two additional thrombolytic infusions of recombinant tissue-type plasminogen activator (rt-PA) because of nonsustained ischemia after initial treatment with rt-PA or streptokinase. Thirty-five patients received the second infusion within 1 h of the first; 13 patients received the second infusion 1 to 72 h after the first and 4 patients received it later during their hospitalization. Bleeding complications occurred in 10 patients (19%); however, most of these were minor (no intracranial bleeding) and only 2 patients required blood transfusion. In 14 patients in whom the decrease in fibrinogen and plasminogen levels was measured after the first and second infusions, this decrease was only 25% and 63%, respectively--only slightly higher than the 22% and 53% decreases measured in 63 patients who had only one rt-PA infusion. In 44 patients (85%), the acute ischemia resolved completely within 1 h after initiation of the second infusion. In 23 patients (44%), pain and ST segment elevation did not recur and invasive coronary intervention was avoided. Thus, repeat rt-PA infusions can stabilize a substantial number of patients with acute reinfarction and, even when relief is temporary, repeat rt-PA infusions can minimize myocardial damage while patients await mechanical revascularization.

Rapid resolution of ST elevation and prediction of clinical outcome in patients undergoing thrombolysis with alteplase (recombinant tissue-type plasminogen activator): results of the Israeli Study of Early Intervention in Myocardial Infarction

Alteplase (recombinant tissue-type plasminogen activator (rt-PA)) was infused within four hours of onset of symptoms in 286 patients with acute myocardial infarction. Delayed coronary angiography was performed 72 hours after admission with coronary angioplasty if indicated. Electrocardiographic monitoring was continuous during the first hour of treatment. The sum of the ST segment elevations (sigma ST) was calculated on electrocardiograms recorded at entry and an hour later. ST elevations resolved rapidly within one hour of treatment in 189 patients and persisted in 97 patients. Rapid resolution of ST elevation correlated with angiographic coronary patency as determined by coronary angiography 72 hours after admission. The patients with rapid resolution of sigma ST had significantly smaller infarcts and a better clinical outcome than the patients with persistent ST elevation. sigma ST values at entry and one hour after treatment had no additional independent predictive value. Rapid resolution of ST elevations in patients undergoing thrombolysis with alteplase was associated with a significantly smaller release of creatine kinase, better preservation of left ventricular function, lower morbidity, and less short and long term mortality. Rapid resolution of sigma ST elevation is an efficient indicator of clinical outcome in groups of patients with acute myocardial infarction undergoing thrombolysis with alteplase.

Resurfacing of skin in hand injuries

The Authors discuss their experience with the use of various flaps (radial artery, groin and abdomen) in the primary or delayed cover of skin defect in the hand, in a total number of 20 cases. All the three types of flaps took up well in 3-4 weeks with minimal complications. The Authors preferred the radial artery flap to the groin and abdominal flaps, in that order.

Randomized controlled trial of late in-hospital angiography and angioplasty versus conservative management after treatment with recombinant tissue-type plasminogen activator in acute myocardial infarction

Although both the European Cooperative Study Group and the Thrombolysis in Myocardial Infarction IIB trial indicated that angiography and angioplasty as routine measures after thrombolytic treatment do not improve clinical outcome in patients with acute myocardial infarction, the potential benefit of angioplasty may have been negated by the fact that the procedure was performed too soon (less than 32 hours) after admission. A similar study was designed in which delayed invasive treatment was compared with conservative treatment in 201 patients with acute myocardial infarction given recombinant tissue-type plasminogen activator. The 97 patients randomized to the invasive group underwent routine coronary angiography and angioplasty 5 +/- 2 days after thrombolytic therapy, whereas the 104 patients randomized to the conservative group underwent angiography only for recurrent postinfarction angina or exercise-induced ischemia. Baseline characteristics of both groups were similar. In the invasive group, 92 patients underwent angiography, 49 angioplasty and 11 coronary artery bypass surgery. In the conservative group, 40 patients experienced early ischemia, 39 underwent angiography, 20 angioplasty and 4 coronary artery bypass surgery. Reinfarction rate and preservation of left ventricular function at discharge or 8 weeks after discharge did not differ in the 2 groups. Total mortality after a mean follow-up of 10 months was 8 of 97 in the invasive and 4 of 104 in the conservative groups (p = 0.15). However, if only patients who died after the timing of the scheduled protocol catheterization in the invasive arm were included, mortality was 5 of 94 and 0 of 100 in the invasive and conservative treatment groups, respectively (p = 0.02). (ABSTRACT TRUNCATED AT 250 WORDS)

Improved survival but not left ventricular function with early and prehospital treatment with tissue plasminogen activator in acute myocardial infarction

One hundred ninety patients with acute myocardial infarction (AMI) were treated with recombinant tissue-type plasminogen activator (rt-PA) 2.0 +/- 0.8 hours after the onset of symptoms. Eighty-seven patients were enrolled via mobile intensive care units and 103 through the emergency ward. Patients who were enrolled via the mobile intensive care units were randomized to immediate, prehospital treatment initiation, or to delayed, in-hospital treatment initiation. All 190 patients except 2 underwent delayed coronary angiography and, when indicated, angioplasty at 72 hours after enrollment. Patients treated within 2 hours and those treated 2 to 4 hours after symptom onset had similar preservation of left ventricular function, and similar prevalence of congestive heart failure at discharge. Patients treated within 2 hours of symptom onset had significantly lower short- (0.0 vs 6.3%, p = 0.01) and long-term (1.0 vs 9.5%, p = 0.03) mortality. Prehospital initiation of rt-PA appeared to be safe and feasible and resulted in a 40-minute decrease in the time from symptom onset to treatment initiation.

Immune response to hepatitis B viral antigens in chronic infection & its relationship with liver necrosis

Markers of hepatitis B virus (HBV) and immune response against them were studied in 18 chronic asymptomatic carriers, 8 patients of the virus induced chronic liver disease (CLD), and 7 patients of chronic alcoholic liver cirrhosis, who were also chronic HBV carriers (CALC). The LMI responses to HBeAg were elevated in HBeAg and/or HBV-DNA positive chronic asymptomatic carriers, (median response 31.5%), along with elevation of serum alanine aminotransferase (sALT) levels (59-150 IU/l). On the other hand the LMI responses to this antigen, in HBeAg and HBV-DNA negative chronic carriers were in the normal range (median response 12%) and their sALT levels were also normal (7-50 IU/l). The CLD and CALC patients did not show any relation between their LMI to HBeAg and sALT levels. In contrast no relation between LMI to HBsAg and sALT levels was observed in any group. The LMI responses to HBsAg in CLD patients were elevated (median response 38%) and the responses of chronic asymptomatic carriers and CALC patients were either in the normal range or poor (median responses, 18 and 7% respectively), irrespective of their sALT levels. These results suggest that T cell responses to both the antigens may be involved in liver cell damage.

Acute hemodynamic and arrhythmogenic effects of high-dose intravenous salbutamol in patients with chronic left ventricular dysfunction

The short-term hemodynamic and possible arrhythmogenic effects of intravenous salbutamol at a dose of 30 or 60 micrograms/min were evaluated in 14 patients with severe chronic left ventricular dysfunction using equilibrium radionuclide angiocardiography and electrocardiographic monitoring. Salbutamol infusions at a dose of 30 micrograms/min did not cause significant hemodynamic changes; however, at a dose of 60 micrograms/min there was a significant increase in stroke volume, cardiac output, and left ventricular ejection fraction. Heart rate increased significantly while systemic peripheral resistance decreased significantly. Two patients developed ventricular premature beats and another two supraventricular tachycardia, but none were associated with adverse consequences. Thus, high-dose intravenous salbutamol is effective and safe, and may be used in the acute management of patients with poor left ventricular function.

Vascular anatomy of the pronator quadratus muscle-bone flap: a justification for its use with a distally based blood supply

The vascular anatomy of the pronator quadratus muscle and distal radius was studied in 24 cadaveric forearms by dissection under magnification and india ink and latex injection studies. The anterior interosseous artery divides into a muscular branch and a dorsal branch 1 cm to 3.5 cm from the proximal margin of the pronator quadratus muscle, and on its deep surface. Injection studies showed a rich periosteal plexus contributed by the anterior interosseous artery. Retrograde injection through the dorsal branch also showed good perfusion of the distal radius that was confirmed microscopically on bone sections. A muscle-bone graft from the anteromedial cortex of distal radius with an intact anterior interosseous artery has mobility of less than 2 cm. After ligating and dividing the anterior interosseous artery, blood supply to the distal radius bone flap relies on a retrograde flow and the bone flap could then be mobilized distally up to 4 to 6 cm.

Should thrombolytic therapy be administered in the mobile intensive care unit in patients with evolving myocardial infarction? A pilot study

The growing recognition of the importance of early thrombolysis in evolving myocardial infarction was the basis for the present study, which evaluated the effectiveness, feasibility and safety of prehospital thrombolytic therapy. In a relatively small study, 118 patients were allocated to receive either prehospital treatment with recombinant tissue-type plasminogen activator (rt-PA) in the mobile intensive care unit (group A, 74 patients) or hospital treatment (group B, 44 patients). A total of 120 mg of rt-PA was infused over a period of 6 h. All patients were fully heparinized and underwent radionuclide left ventriculography and coronary angiography during hospitalization. Although group A was treated significantly earlier than group B after onset of symptoms (94 +/- 36 versus 137 +/- 45 min, respectively; p less than 0.001), no significant differences were observed between the groups in 1) extent of myocardial necrosis, 2) global left ventricular ejection fraction at discharge, 3) patency of infarct-related artery, 4) length of hospital stay, and 5) mortality at 60 days. However, a trend to a lower incidence of congestive heart failure at hospital discharge was observed in the prehospital-treated compared with the hospital-treated group (7% versus 16%, respectively; p = NS). No major complications occurred during transportation. It is concluded that myocardial infarction can be accurately diagnosed and thrombolytic therapy initiated relatively safely during the prehospital phase by the mobile intensive care team, thus instituting a beneficial clinical trend in favor of prehospital thrombolysis.

Tissue-specific expression of allogeneic class II MHC molecules induces neither tissue rejection nor clonal inactivation of alloreactive T cells

To analyze the control of self tolerance to tissue-specific Ag, we have constructed C57BL/6 (H-2b) transgenic mice that express allogeneic class II (I-Ad) molecules exclusively on pancreatic islet cells. By a number of criteria, including I-Ad mRNA, and tissue and cell surface I-Ad protein levels, the islet cells appear to be expressing levels of I-Ad similar to B lymphocytes. Although one of the transgenic lines that expresses only the beta-chain occasionally displays slightly elevated glucose levels, this hyperglycemia is not enhanced when alpha and beta are coexpressed, allowing for cell surface I-Ad expression. None of the mice examined has demonstrated any autoimmune reaction to the I-Ad+ islet cells. Despite this apparent lack of recognition of the I-Ad+ islet cells, these animals demonstrate no reduction in the in vitro MLR generated to the same MHC molecule. Therefore, these mice remain functionally tolerant to the transgene product without inactivating those T cells that can recognize this same MHC molecule in vitro.

The slope of the end-systolic pressure-volume relationship compared with the global end-systolic pressure-volume ratio in humans

The slope of the end-systolic pressure-volume relationship (Emax), which is generated clinically by load manipulation, as well as the "absolute" peak systolic pressure end-systolic volume ratio (denoted as pressure-volume ratio), have been suggested as indices defining left ventricular function. This study represents an attempt to determine the relationship between these two indices by studying 20 patients (16 with coronary artery disease and 4 with normal coronary arteries) undergoing cardiac catheterization. Left ventriculography was performed three times in each patient: (1) in the control baseline state, (2) after rapid intravenous infusion of 250-300 cc of saline, and (3) after sublingual administration of 5 mg isosorbide dinitrate. Emax was approximated by linear regression using the peak left ventricular pressure (replacing end-systolic pressure) and the smallest left ventricular (end-systolic) volume for these three different loads. Acute ischemia with typical chest pain and ECG changes developed in 4 patients during saline loading. The pressure-volume ratio showed no change with load manipulation in patients who did not demonstrate ischemia. In the 4 patients who developed acute ischemia, the pressure-volume ratio dropped from 4.4 +/- 1.3 to 2.9 +/- 0.9 mmHg/ml (p less than 0.001). In all of the patients, the pressure-volume ratio, but not the Emax, correlated with the ejection fraction (r = 0.6; p less than 0.05). In addition, the Emax line demonstrated a markedly nonphysiological Vo. There was no correlation between Emax and pressure-volume ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue-specific expression of allogeneic class II MHC molecules induces neither tissue rejection nor clonal inactivation of alloreactive T cells

To analyze the control of self tolerance to tissue-specific Ag, we have constructed C57BL/6 (H-2b) transgenic mice that express allogeneic class II (I-Ad) molecules exclusively on pancreatic islet cells. By a number of criteria, including I-Ad mRNA, and tissue and cell surface I-Ad protein levels, the islet cells appear to be expressing levels of I-Ad similar to B lymphocytes. Although one of the transgenic lines that expresses only the beta-chain occasionally displays slightly elevated glucose levels, this hyperglycemia is not enhanced when alpha and beta are coexpressed, allowing for cell surface I-Ad expression. None of the mice examined has demonstrated any autoimmune reaction to the I-Ad+ islet cells. Despite this apparent lack of recognition of the I-Ad+ islet cells, these animals demonstrate no reduction in the in vitro MLR generated to the same MHC molecule. Therefore, these mice remain functionally tolerant to the transgene product without inactivating those T cells that can recognize this same MHC molecule in vitro.

Double-stranded RNA and bacterial lipopolysaccharide enhance sensitivity to TNF-alpha-mediated cell death

The effect of double-stranded RNA (dsRNA) and bacterial lipopolysaccharide on the sensitivity to tumor necrosis factor (TNF)-alpha-mediated cell death was studied in an in vitro system. Since secretion of TNF-alpha is a part of the early host response to viral and bacterial infection, we examined whether mimicking the infection with viral and bacterial products could affect the response of cells to TNF-alpha. Incubation of WEHI 164 fibrosarcoma cells with dsRNA or lipopolysaccharide (LPS) significantly increased their sensitivity to TNF-alpha-mediated lysis and to TNF-secreting inflammatory T cell-mediated lysis. Thus, these products could induce increased sensitivity to TNF-alpha in cells in an inflammatory focus, possibly contributing to selective elimination of infected but not healthy cells by this non-specific cytokine. Additionally, our data show that both dsRNA and LPS, as well as TNF-alpha itself, rapidly induce nuclear factor-kappa B (NF-kappa B), a DNA-binding protein implicated in regulation of gene expression. We suggest that NF-kappa B could regulate genes crucial for the induction of cell death by TNF-alpha.

Orbital reconstruction in fibrous dysplasia--a case report

A case of orbitofrontal fibrous dysplasia with optic canal involvement is reported. Surgical excision of the mass with unroofing of the optic canal followed by orbito-cranian reconstruction by methyl methacrylate gave excellent results.

Correlation of baseline plasminogen activator inhibitor activity with patency of the infarct artery after thrombolytic therapy in acute myocardial infarction

Increased levels of plasminogen activator inhibitor (PAI) have recently been described in patients with acute myocardial infarction (AMI). To correlate PAI levels to patency of infarct arteries after thrombolytic therapy with recombinant tissue-type plasminogen activator (rt-PA), 125 consecutive patients with AMI were examined. Blood levels of fibrinogen, plasminogen, tissue plasminogen activator (t-PA) and PAI were measured before treatment initiation, 10 minutes after completion of rt-PA infusion and 24 and 48 hours after treatment. Coronary angiography, performed in all patients 72 hours after beginning rt-PA infusion, revealed patent infarct arteries in 97 patients and occluded infarct arteries in 28 patients. Pretreatment levels of PAI were significantly higher in patients with occluded infarct arteries (18.0 +/- 11.5 vs 10.5 +/- 9.3 IU/ml, p less than 0.01). Conceivably, higher levels of PAI may interfere with the natural thrombolytic process and make pharmacologic thrombolytic intervention less effective.

Atypical Wilson disease--a case report with CT scan

A case of atypical Wilson disease is being reported. Possible mechanism of the process, diagnostic features and CT appearance of brain is described. Early detection and therapy with copper chelating agents result in neurologic and performance improvement of patients.

Quantitative analysis of idiotypic mimicry and allelic exclusion in mice with a mu Ig transgene

Analysis of C57BL/6 mice (IgM allotype, Igh-6b or mu b) that carry an Ig H chain transgene of a different allotype (mu a) shows that IgM molecules of mixed allotype (mu a mu b) are present among serum antibodies. The finding was extended to hybridomas prepared from nonimmune transgenic mice, many of which also failed to exhibit allelic exclusion. The proportions of mu a and mu b secreted by individual hybridomas varied markedly, and the product of an individual hybridoma was found to be heterogeneous with respect to the allotype content of individual molecules. The ratio of mu a:mu b chains secreted by individual hybridomas was found to correlate with the number of transgene copies remaining in each hybridoma, and several hybridomas that secrete only mu b-positive molecules had apparently lost all but one copy of the transgene. An idiotype characteristic of the transgene was found to be present only in association with the transgenic (mu a) allotype, and indirect evidence strongly suggests that the idiotype was present only on mu a polypeptide chains. Thus, there is no evidence in this system for the induction of idiotypically cross-reactive endogenous molecules.

Quantitative analysis of idiotypic mimicry and allelic exclusion in mice with a mu Ig transgene

Analysis of C57BL/6 mice (IgM allotype, Igh-6b or mu b) that carry an Ig H chain transgene of a different allotype (mu a) shows that IgM molecules of mixed allotype (mu a mu b) are present among serum antibodies. The finding was extended to hybridomas prepared from nonimmune transgenic mice, many of which also failed to exhibit allelic exclusion. The proportions of mu a and mu b secreted by individual hybridomas varied markedly, and the product of an individual hybridoma was found to be heterogeneous with respect to the allotype content of individual molecules. The ratio of mu a:mu b chains secreted by individual hybridomas was found to correlate with the number of transgene copies remaining in each hybridoma, and several hybridomas that secrete only mu b-positive molecules had apparently lost all but one copy of the transgene. An idiotype characteristic of the transgene was found to be present only in association with the transgenic (mu a) allotype, and indirect evidence strongly suggests that the idiotype was present only on mu a polypeptide chains. Thus, there is no evidence in this system for the induction of idiotypically cross-reactive endogenous molecules.

Oxytocin-induced tenosynovitis and extensor digitorum tendon rupture

A rare case of aseptic tenosynovitis from oxytocin injection in the vicinity of a tendon causing spontaneous rupture of the extensor digitorum communis tendon is reported.

Route-related variation in the immunogenicity of killed Salmonella enteritidis vaccine: role of antigen presenting cells

In order to assess the role of the route of immunization on the immunogenicity of killed Salmonella vaccine, mice were immunized with killed S. enteritidis by intraperitoneal (i.p.) and intradermal (i.d.) routes. Whereas the former was non-immunogenic, the i.d. immunization generated an excellent delayed-type hypersensitivity response; further, i.p. immunization could even suppress the subsequent i.d. immunization. Since the peritoneal macrophages (MO) are known to be particularly low in Ia or MHC-class II antigens, so essential for antigen presentation, the non-immunogenicity by i.p. route was thought to be due to their poor presentation efficiency. Poly I: poly C, an interferon inducer, is known to enhance the MHC-class II expression; hence effect of poly I: poly C treatment on the immunogenicity of the killed vaccine by i.p. route was tested and indeed the non-immunogenicity was corrected. Poor efficiency of presentation of S. enteritidis antigen by peritoneal cells and its improvement by prior poly I: poly C treatment was further confirmed by in vitro lymphocyte transformation test using primed T cells and peritoneal cells from normal and poly I: poly C treated mice. Poly I: poly C treatment also enhanced expression of Ia antigens on peritoneal cells.

Modified posterior soft tissue release for management of severe knee flexion contracture

A modified posterior soft tissue release has been used in treating severe flexion contracture of the knee in 30 patients (36 knees). The operative technique has been modified with respect to the skin incision, and lengthening of the medial hamstrings. It is performed without a tourniquet. Postoperative skeletal traction was applied with gradual increasing weight to rapidly correct residual deformity. The deformity was fully corrected in 30 knees. The only complication was superficial skin necrosis over a small area, which occured in two knees. In six knees, 10 degrees of flexion deformity persisted after treatment. In four additional knees, 10 degrees of flexion deformity recurred due to lack of continued therapy. The modified posterior soft tissue release operation gave good results without any serious complications.

A novel MHC class II epitope expressed in thymic medulla but not cortex

The repertoire of receptors expressed by peripheral T cells is the result of two selective events that occur during intrathymic development. Positive selection expands cells able to recognize foreign peptides presented by self MHC molecules, and negative selection eliminates cells reactive to self MHC molecules and associated self peptides. Chimaera studies suggest that, at least in the case of T cells recognizing MHC class II, interaction with thymic cortical epithelial cells is responsible for the former, whereas thymic medullary cells, of bone marrow origin, mediate the latter. This view of thymic development is supported by recent morphometric analyses, showing that autoreactive cells are found in thymic cortex but not medulla. Although numerous studies have shown that MHC class II molecules are expressed in both sites, none provides any explanation for the differential selection of T cells that is observed. Here, we describe a novel MHC class II epitope which is found on cells in thymic medulla but not cortex. The antibody to this epitope reacts with about 10% of class II molecules on B cells and may be recognizing a self peptide-MHC complex. These results provide the first evidence for differential expression of class II epitopes in different tissues and are compatible with the hypothesis that different ligands, rather than different affinity thresholds for the same ligand, are involved in positive and negative selection of the T-cell repertoire.

Isotype switching by a microinjected mu immunoglobulin heavy chain gene in transgenic mice

Immunization of transgenic mice carrying an immunoglobulin mu heavy chain resulted in a response dominated by expression of the transgene variable region. Unexpectedly, in a large proportion of the antibody produced by immunized mice, the transgene variable region was associated with IgG rather than IgM. This demonstrates that the transgene can undergo an isotype switch. Four transgenic founder lines all exhibited transgene isotype switching despite the likelihood of random chromosomal integration of the transgene. In addition one of the lines was analyzed by breeding studies and the transgene was found to be genetically unlinked to the immunoglobulin heavy chain (Igh) locus. These results indicate that a precise chromosomal location is not required for isotype switching and suggest the possibility that the isotype switching process can occur interchromosomally.

Cross-linking and conformational change in T-cell receptors: role in activation and in repertoire selection

TCRs undergo a series of interactions with ligands during development. We have characterized the interaction of a TCR with its ligand and the attendant co-receptor and co-ligand structures. This characterization has led to the model in which the TCR not only binds to class II MHC, but also binds to CD4 co-receptors and co-ligands such as Mls. We have shown that both cross-linking and conformational change in the TCR are required for optimal T-cell activation. Finally, we have used the observation that a particular self-peptide found abundantly associated with class II MHC in the periphery is essentially lacking from thymic cortical epithelium to argue that positive selection for self-MHC recognition may occur by a novel process in the thymic cortex. A TCR recognizing class II MHC with low affinity could either be multiply cross-linked in the absence of conformational change, which here would be driven by a unique peptide, or could be conformationally changed without cross-linking due to the rarity of the individual high-affinity peptide on thymic cortical epithelial cells. Either proposal leads to a partial signal one delivered via the TCR, which we refer to as signal one-half. This signal one-half would induce the cell to repress its other co-receptor molecule and to undergo maturation events such as up-regulation in TCR expression. Such cells are then rigorously screened for activating interactions with autologous structures, such as Mls. The threshold for clonal deletion is set very low to avoid autoreactivity. By this combination of signaling events, a mature TCR repertoire is generated that has the functional characteristics observed in immune systems.

Anti-idiotypic humoral and cellular responses to antibody to hepatitis B surface antigen in hepatitis B viral infections

In order to investigate regulatory significance of humoral and cellular responses to the idiotypic (Id) determinants on the antibody to hepatitis B surface antigen (anti-HBs), they were studied in acute hepatitis B and in chronic HBV infection. The results were compared with humoral and cellular responses of the same patients to hepatitis B surface antigen (HBsAg). In acute hepatitis B, the responses to HBsAg, were delayed until 3-4 weeks after the onset of clinical symptoms. However, the leucocyte migration inhibition (LMI) and the lymphocyte transformation (LTT) responses to affinity purified anti-HBs were found to be evolved very early in the course of acute hepatitis B, though anti-Id antibodies were absent. The majority of chronic HBV carriers showed a poor humoral and cellular response to HBsAg. Ten out of 38 chronic carriers showed anti-Id antibodies which recognized a major cross-reactive idiotype (CRI) on the anti-HBs molecule. Twenty-five out of 38 chronic carriers also showed LMI response to the Id determinants on the anti-HBs. LMI response induced by anti-HBs could be blocked by a specific Balb/c anti-Id antibody which also recognized the CRI. Thus, in both acute and chronic HBV infections, the anti-Id humoral and cellular responses correlated with poor humoral and cellular responses to HBsAg, indicating regulatory significance.

Characterization of regional left ventricular contraction by curvature difference analysis

A method which characterizes the contraction of the left ventricle (LV) by changes in the LV endocardial contour curvatures is presented. A normalized curvature difference function (NCDF) is defined by the difference between the (normalized) curvature functions of end diastolic (ED) and end systolic (ES) contours. Unlike wall-motion based procedures, NCDF is independent of any reference system and of the method used for ED-ES shape alignment. Normal and pathological diagnosis criteria were first established based on right anterior oblique (RAO) projection ventriculograms of a study group which included 58 normal and 28 abnormal patients. Patients with an infarcted myocardial region differed from the characteristic NCDF pattern of normals and exhibited regionally defined irregularities. The diagnosis criteria were then applied to a total of 159 patients in two groups in two independent laboratories. One group (in Israel) included 49 cases (20 normals, 29 abnormals); the second (in France) included 108 cases (48 normals, 60 abnormals). These two groups yielded similar sensitivity (97% and 97%) and specificity (90% and 100%) in detection of abnormality of the ventricle. When tested against other quantitative wall motion techniques, the NCDF shwos a regional sensitivity of 95%, indicating that curvature difference analysis is a potential tool for the automatic and objective diagnosis of regional LV function abnormalities.

IgG subclass composition of antibodies to HBsAg in circulating immune complexes from patients with hepatitis B virus infections

The IgG subclass of antibody associated with hepatitis B surface antigen (HBsAg) in circulating immune complexes (CIC) from patients with either acute or chronic hepatitis B virus (HBV) infections was measured using an isotype and antigen-specific ELISA. All patients were HBsAg positive but were negative for free anti-HBs antibody. The subclass of antibody associated with HBsAg in CIC in both groups was predominantly IgG1 and IgG4. This is in contrast to free anti-HBs in convalescent sera from patients recovering from HBV infection, which are highly restricted to IgG1 and IgG3. The finding of high levels of IgG4 antibodies in CIC suggest that CIC containing this subclass may be cleared less efficiently than CIC containing antibodies of other subclasses. Formation of these CIC may be an important factor in the progression of infection to chronicity and may also be involved in the antigen-specific immunosuppression seen in early acute and chronic HBV infections.

Functional affinity of IgM rheumatoid factor in patients with rheumatoid arthritis and other autoimmune diseases

The functional affinity of IgM rheumatoid factors (RF) was measured in 31 patients with rheumatoid arthritis (RA), 24 with systemic lupus erythematosus (SLE), 13 with Sjögren's syndrome (SS), and in 13 seropositive healthy individuals. The functional affinity of IgM RF from patients with RA was significantly lower than in the other clinical groups studied. In addition, there was a significant inverse correlation between functional affinity and titre of IgM RF in all the groups. These results suggest that the usual mechanisms of affinity based selective pressure (somatic diversification and antigen selection) may operate differently for autoantibodies to serum antigens such as IgG.

An inhibition enzyme immunoassay for estimating relative antibody affinity and affinity heterogeneity

A method to measure the relative affinity of antibodies using an inhibition enzyme immunoassay is described. It is validated using monoclonal antibodies of defined affinity characteristics and by comparison with conventional methods of affinity measurement. The method allows measurement of the relative affinity of low levels of antibody, and the calculation of an empirical estimate of the heterogeneity of affinity in antibody populations.

Determination of the functional affinity of IgG1 and IgG4 antibodies to tetanus toxoid by isotype-specific solid-phase assays

Two solid-phase assays have been used to measure the affinity of IgG1 and IgG4 antibodies to tetanus toxoid (TT) in whole sera. In the first assay, low affinity antibodies were selectively inhibited from binding to solid-phase antigen by a mild chaotropic agent and in the second assay, high affinity antibodies were preferentially inhibited from binding by low concentrations of free antigen. Results from both assays suggest that IgG4 antibodies to TT are of lower functional affinity than IgG1 antibodies and that, in addition, IgG4 responses to TT display a more restricted affinity heterogeneity.

Hemodynamic effects of oral isosorbide-5-mononitrate and dinitrate in ischemic heart failure

Isosorbide-5-mononitrate (ISMN), the main metabolite of isosorbide dinitrate (ISDN) was recently introduced in clinical use. The hemodynamic effects of oral ISMN and ISDN, administered in equal doses, were studied in a randomized, crossover fashion in 20 patients with pump failure of ischemic etiology. Baseline hemodynamic criteria for admission into the study were: pulmonary capillary wedge pressure (PCW) of at least 20 mmHg and systolic arterial pressure (AP) above 90 mmHg. Hemodynamic parameters were serially measured and systemic vascular resistance was calculated up to 6 h postadministration of either ISMN or ISDN single dose (40 mg). Maximal effects obtained were statistically significantly different from baseline. While ISMN and ISDN appeared to be equipotent in reducing the filling pressure, with a maximum effect reached in 60-120 min, the mononitrate maintained its effects for a longer period.

Virological markers and antibody responses in fulminant viral hepatitis

Clinical profiles, serological markers, and antibody responses to antigens of hepatitis B virus (HBV) were studied in patients with fulminant viral hepatitis. Whereas hepatitis A and B were found to be uncommon causes (6.9% and 12.2%, respectively), non-A, non-B (NANB) hepatitis was found to be the most common cause of fulminant hepatitis (80.9%). As against this, the incidence of hepatitis B and NANB hepatitis was very similar in nonfulminant acute viral hepatitis in adults (41.2% and 51.9%, respectively). Pregnancy with labour was an important precipitating factor for development of fulminant hepatitis of the NANB type only; 32% of fulminant NANB hepatitis patients were pregnant women and 22.6% had a history of labour preceding hepatic coma. Only 0.8% of nonfulminant NANB hepatitis cases were pregnant women. Another major precipitating factor for the development of the fulminant form of NANB hepatitis was concomitant chronic HBV carrier state. A total of 38.6% of fulminant NANB hepatitis patients were HBV carriers, whereas only 19.2% of nonfulminant acute NANB hepatitis cases were HBV carriers. Sera of 32 chronic HBV carriers with fulminant NANB hepatitis and 10 cases of fulminant hepatitis B were tested for delta antibody, and all were nonreactive. The antibody responses of the fulminant hepatitis B patients to the antigens of HBV were found to be greater compared to those of patients with nonfulminant acute hepatitis B. Antibody responses of chronic HBV carriers with fulminant NANB hepatitis to antigens of HBV were found to be depressed in comparison with those of chronic asymptomatic carriers.

Mechanisms of liver cell damage in acute hepatitis B

Markers of hepatitis B viral infection and the evolution of immune response to these were compared with serum alanine aminotransferase (ALT) levels in adult male and non-pregnant and pregnant female patients with acute hepatitis B from the time of onset of disease to the seventh week. In the adult male and non-pregnant female patients, the peak ALT levels of about 360 IU/litre, seen at the time of onset, gradually declined during the course of the disease. Significantly, even in the seventh week, the median ALT level was abnormal (80 IU/litre). In contrast, the disease was mild in pregnant patients and the ALT levels declined rapidly, returning to normal by the third week. Markers associated with HBV replication, i.e., serum HBV-DNA and HBeAg, declined early in the course of the disease in both groups. The anti-HBc-IgM and anti-HBe responses were well evolved early in the course of the disease in both groups. HBsAg was present in the serum in large amounts (1-1.5 X 10(4) AU/100 microliter) early in the course of the disease and remained so up to the seventh week. Even the pregnant patients who had recovered clinically by the fourth week continued to have HBsAg in their sera in large amounts in spite of normal ALT levels. LMI and LTT responses to HBsAg, which were practically absent in the first week, gradually increased to a peak during the fourth week and remained elevated up to the seventh week in adult male and non-pregnant female patients. In contrast, LMI response to HBsAg was absent in pregnant patients with acute hepatitis B even up to the fourth week Thus, continued liver cell necrosis after the fourth week, as indicated by raised ALT levels, may be associated with T cell responses to HBsAg.

Regulation of cell-mediated immunity in mice immunised with Salmonella enteritidis

The effects of diverse factors, such as route of immunisation, composition of immunogen and administration of interferon inducer, on the expression of cell-mediated immune responses against Salmonella enteritidis were investigated in BALB/c and Swiss white mice. Immunisation with live cells of S. enteritidis by the intraperitoneal route (ip) generated both delayed type hypersensitivity (DTH) and protective cell-mediated immunity (CMI). However, the two responses showed diametrically opposite time kinetics. The decline and disappearance by 9 weeks after ip immunisation of DTH and the rise of protective immunity in the same period suggested the possibility that the two responses were mediated by different subsets of T cells. Immunisation by the intradermal (id) route with a sonicate of S. enteritidis generated only DTH; id immunisation also suppressed the development of the protective response following ip immunisation with live S. enteritidis. Both responses were not seen when T cells were eliminated with anti-T cell serum. Oral immunisation with live cells of S. enteritidis induced excellent CMI expressing both DTH and protective responses. On the other hand, oral immunisation with the sonicate of S. enteritidis not only did not induce CMI, but also prevented the development of the DTH and protective response to ip immunisation with live S. enteritidis. Induction of interferon by the administration of poly I: poly C for four consecutive days after id immunisation with killed S. enteritidis suppressed the generation of DTH.

Review of echocardiographically diagnosed right heart entrapment of pulmonary emboli-in-transit with emphasis on management

2DE permits detection of thromboemboli transiently entrapped in the right heart chambers while en route to the pulmonary arteries. Review of the 49 cases recorded to date reveals that the supple elongated clot produces a 2DE picture--a mass of changing configuration and striking mobility--that is highly characteristic. Since emboli that become entrapped are large, when managed by medical measures alone they have an attendant mortality rate of 50%, usually soon after 2DE diagnosis, upon completion of pulmonary embolization. Death occurred in 8 of 16 patients treated with anticoagulants, thrombolytic agents, or antiaggregants and in 6 of 13 who received supportive measures only. Of 20 patients referred for surgery (cardiotomy and, in 17, pulmonary embolectomy), only three died, two of them failures of preceding anticoagulant treatment. These data indicate that thromboemboli entrapped in the right heart chambers are best handled as a surgical emergency.

Two-dimensional echocardiographic analysis of proximal left main coronary artery in humans

The left main coronary artery (LMCA) was evaluated in 100 consecutive patients (88 men and 12 women; mean age 63 years) with anginal syndrome, all in New York Heart Association classes II and III. Each patient underwent two-dimensional echocardiography (2DE) from the parasternal short-axis and apical four-chamber views. Coronary angiography was subsequently performed within 24 hours. The LMCA was directly measured by 2DE and coronary angiography at its widest point. Each echocardiogram was blindly evaluated for LMCA aneurysm or obstruction. Eight patients (8%) were excluded because of inadequate visualization of the LMCA. The mean 2DE measurement was 4.4 +/- 0.9 mm vs 4.2 +/- 0.8 mm on coronary angiography (r = 0.86). Atherosclerotic aneurysms of the LMCA were correctly diagnosed in two patients by 2DE. LMCA stenosis (greater than 50%) was found in 11 patients on coronary angiography; three of them had ostial or proximal lesions, three had middle lesions, and five had distal lesions. 2DE correctly diagnosed all three ostial lesions, two of three middle lesions, but only two of five distal lesions. In four patients, dense echoes in the LMCA caused a false positive diagnosis. It was concluded that: the LMCA can be visualized and correctly measured by 2DE; atherosclerotic aneurysms can be detected; and 2DE is yet unable to screen patients for LMCA lesions; however, 2DE is a promising method for evaluating proximal and especially ostial LMCA stenosis.

Changes in systemic vascular resistance detected by the arterial resistometer: preliminary report of a new method tested during percutaneous transluminal coronary angioplasty

A recently developed apparatus provides on-line continuous monitoring of systemic vascular resistance (SVR) by means of simple computer analysis of the peripheral arterial waveform. The fundamental equation of this method is Ri = P'/(dP/dt), where dP/dt is the peak dP/dt of the peripheral arterial waveform, P' is the pressure at time of peak dP/dt, and Ri is a resistance index that bears a direct relation to SVR. Eleven patients undergoing percutaneous transluminal coronary angioplasty (PTCA) were studied to evaluate the changes in SVR associated with myocardial ischemia (angina detection). There were 49 balloon inflations, all of which were associated with an increase in Ri (from 38.4 +/- 12 to 81.2 +/- 36 X 10(-3) sec; p less than .01) and a decrease in dP/dt (from 2076 +/- 257 to 1327 +/- 326 mm Hg/sec; p less than .01). In 42 of the balloon inflations these changes were associated with electrocardiographic ST-T changes and in 23 it was also associated with anginal pain. When angina was present, a further increase in Ri (to 97.5 +/- 43 X 10(-3) sec; p less than .01) and a decrease in dP/dt (to 1218 +/- 338 mm Hg/sec; p less than .01) was observed. It was found that myocardial ischemia is associated with an increase in the resistance index and a decrease in dP/dt and can be detected by the resistometer.

Severe aortic regurgitation: a rare presentation of giant cell arteritis

A 53-year-old patient with no past history of rheumatic fever or lues presented with severe aortic regurgitation, underwent hemodynamic evaluation, and subsequently, an uneventful aortic valve replacement. The initial pathological interpretation was nonspecific aortitis. Six months following surgery arthralgia, muscular pain, difficulty in mastication, and fatigue occurred. There was no fever, however, sedimentation rate was 100/130. Cardiac examination was normal. Review of the pathological specimens revealed granulomatous arteritis with giant cells, typical of giant cell arteritis. Though the association of aortic regurgitation and giant cell arteritis is well recognized, only two such cases of severe aortic regurgitation requiring valve replacements have yet been described, of them, one probably had Takayasu's arteritis. An accurate diagnosis is of importance since steroid treatment is effective, and if introduced early, the inflammatory process may be arrested.