Isolation and RNA-binding analysis of NAD+ -isocitrate dehydrogenases from Kluyveromyces lactis and Schizosaccharomyces pombe.

Krebs cycle NAD+ -isocitrate dehydrogenase (Idh) binds to the 5-UTRs of all mitochondrial mRNAs in Saccharomyces cerevisiae. We hypothesize that this leader-binding activity plays a role in translational regulation, thereby linking mitochondrial biogenesis to the need for respiratory function. Analysis of effects of leader binding on mitochondrial translation is complicated by the involvement of the enzyme in mitochondrial metabolism. We have therefore searched for an Idh altered in RNA binding, but retaining full enzyme activity. Idh from Kluyveromyces lactis and Schizosaccharomyces pombe was partially purified and examined for the ability to bind Cox2 mRNA. Sch. pombe Idh, like the S. cerevisiae enzyme, has high affinity for both its own, K. lactis and S. cerevisiae COX2 leaders. In contrast. Idh purified from K. lactis shows only low affinity for all mRNAs tested. To determine what distinguishes K. lactis Idh from S. cerevisiae Idh, genes encoding the two subunits of Idh in K. lactis were cloned and sequenced. Sequence comparison revealed high levels of similarity throughout the proteins, in particular in regions involved in enzyme activity, co-factor and regulator binding. Non-conserved residues between the subunits from the two yeasts are candidates for involvement in the interaction with RNA.

Primary thyroid lymphoma.

A 71-year-old woman presented with a rapidly growing goitre which was diagnosed as chronic autoimmune thyroiditis. Despite treatment with levothyroxine, she developed progressive airway obstruction. Biopsy revealed a primary thyroid lymphoma which was successfully treated with radiotherapy.

Kikuchi's histiocytic necrotizing lymphadenitis.

Kikuchi's lymphadenitis was first recognized almost 25 years ago in Japan as a histopathologically specific reactive lymphadenitis without clear clinical correlates. The benign self-limiting clinical course and the notorious danger of misdiagnosis as malignant lymphoma together make it important to recognize this lymph node reaction type. We describe 2 typical case histories-young women with a cervical localisation.

Mondor's disease as first thrombotic event in hereditary protein C deficiency and anticardiolipin antibodies.

A 45-year-old Caucasian woman presented with superficial thrombophlebitis of the right arm and right anterior thoracic wall after bilateral breast surgery followed by spontaneous left anterior thoracic vein thrombophlebitis 3 months later. Besides breast surgery and use of oral contraceptives, hereditary protein C deficiency and anticardiolipin antibodies were found as causes for this bilateral Mondor's disease.

T cell interleukin-17 induces stromal cells to produce proinflammatory and hematopoietic cytokines.

Analysis of the cDNA encoding murine interleukin (IL) 17 (cytotoxic T lymphocyte associated antigen 8) predicted a secreted protein sharing 57% amino acid identity with the protein predicted from ORF13, an open reading frame of Herpesvirus saimiri. Here we report on the cloning of human IL-17 (hIL-17), the human counterpart of murine IL-17. hIL-17 is a glycoprotein of 155 amino acids secreted as an homodimer by activated memory CD4+ T cells. Although devoid of direct effects on cells of hematopoietic origin, hIL-17 and the product of its viral counterpart, ORF13, stimulate epithelial, endothelial, and fibroblastic cells to secrete cytokines such as IL-6, IL-8, and granulocyte-colony-stimulating factor, as well as prostaglandin E2. Furthermore, when cultured in the presence of hIL-17, fibroblasts could sustain the proliferation of CD34+ hematopoietic progenitors and their preferential maturation into neutrophils. These observations suggest that hIL-17 may constitute (a) an early initiator of the T cell-dependent inflammmatory reaction; and (b) an element of the cytokine network that bridges the immune system to hematopoiesis.

Generation and characterization of a human monoclonal autoantibody that acts as a high affinity interleukin-1 alpha specific inhibitor.

Interleukin-1 (IL-1) defines two polypeptides, IL-1 alpha and IL-1 beta, that possess a wide spectrum of biological effects. Two natural antagonists of IL-1 action have been characterized: the IL-1 receptor antagonist (IL-1Ra) and a soluble form of the type II IL-1 receptor. Neutralizing autoantibodies to IL-1 alpha have also been detected in sera of healthy individuals and patients with autoimmune or inflammatory diseases. To characterize such antibodies molecularly, we attempted to generate B cell clones producing anti-IL-1 alpha human monoclonal antibody (HuMAb) by combining Epstein-Barr virus-immortalization and CD40-activation of B lymphocytes from individuals with circulating anti-IL-1 alpha. We describe herein the generation and properties of a natural IgG4/kappa anti-IL-1 alpha monoclonal autoantibody, HuMAb X3, that bound specifically to human IL-1 alpha, but not to IL-1 beta and IL-1Ra, with a high affinity (Kd = 1.2 x 10(-10)M). HuMAb X3 inhibited IL-1 alpha binding to IL-1 receptors and neutralized biological activities of both recombinant and natural forms of IL-1 alpha. A recombinant form of HuMAb X3 was found to display identical specific IL-1 alpha antagonism. The presence of somatic mutations within X3 variable regions suggests an antigen-driven affinity maturation. This study extends the demonstration of the presence of high affinity neutralizing anti-IL-1 alpha autoantibodies that can function as a third type of IL-1 antagonist.

Listeria monocytogenes endocarditis in a patient with an aortic prosthetic valve.

Patients with prosthetic cardiac valves have an increased risk of developing bacterial endocarditis. The causative micro-organism in bacterial endocarditis may be a guide to the portal of entry. In this case report, we describe a patient with a prosthetic cardiac valve who suffered from recurrent endocarditis with different micro-organisms from the gastrointestinal tract.

[Allergy for human insulin]. / Allergie voor humane insuline.

In two patients, a man aged 55 years (patient A) and a man aged 67 years (patient B), severe immediate (type I) and severe delayed (type IV) local reactions to injections of human insulin, respectively, were diagnosed. There had been no previous treatment with insulin of animal origin. The diagnosis of type I allergy was based on the typical early local reaction with biphasic course, the positive immediate skin test and the raised specific IgE level against insulin. The diagnosis of type IV allergy was based on the characteristic late local reaction after 12 hrs, the delayed positive skin test and the negative specific IgE. The first attempt to desensitise patient A in 10 days was not successful, but he was desensitised successfully in 25 days. Patient B recovered spontaneously.

Adrenal insufficiency secondary to postoperative bilateral adrenal haemorrhage.

Two case reports are presented of adrenal insufficiency due to bilateral adrenal haemorrhage following surgery. This unusual complication with its non-specific manifestations may result in unexpected clinical deterioration of the postoperative patient. Corticosteroid replacement and repletion of sodium and water deficits should be given promptly when adrenal haemorrhage is suspected.

Pleural effusion without ascites in a patient with cirrhosis.

The development is described of a massive right pleural effusion in a patient with alcoholic cirrhosis of the liver and alcoholic hepatitis, but without ascites. The literature is reviewed.

The complete sequence of a 33 kb fragment on the right arm of chromosome II from Saccharomyces cerevisiae reveals 16 open reading frames, including ten new open reading frames, five previously identified genes and a homologue of the SCO1 gene.

We report here the sequence of a 33,117 bp DNA fragment located approximately 30 kb from the centromere on the right arm of Saccharomyces cerevisiae chromosome II. We have detected 16 open reading frames (ORFs) longer than 450 bp, provisionally called YBR0301 to YBR0322, covering 70.4% of the entire sequence. The ORFs YBR0301, YBR0302, YBR0303, YBR0305 and YBR0315 correspond to previously sequenced S. cerevisiae genes GAL10, GAL1, FUR4, CAL1 and L2B, respectively. Translation products of two other ORFs, YBR0308 and YBR0312 exhibit similarity to previously known S. cerevisiae proteins: the mitochondrially associated protein SCO1 and the protein kinase YKR2. The predicted protein product of the ORF YBR0321 shows a 41.6% identity score with the Escherichia coli pyroxamine 5'-phosphate oxidase. The nine other ORFs show no significant homology to known proteins.

The yeast nuclear gene MRF1 encodes a mitochondrial peptide chain release factor and cures several mitochondrial RNA splicing defects.

We report the molecular cloning, sequencing and genetic characterization of the first gene encoding an organellar polypeptide chain release factor, the MRF1 gene of the yeast Saccharomyces cerevisiae. The MRF1 gene was cloned by genetic complementation of a respiratory deficient mutant disturbed in the expression of the mitochondrial genes encoding cytochrome c oxidase subunit 1 and 2, COX1 and COX2. For COX1 this defect has been attributed to an impaired processing of several introns. Sequence analysis of the MRF1 gene revealed that it encodes a protein highly similar to prokaryotic peptide chain release factors, especially RF-1. Disruption of the gene results in a high instability of the mitochondrial genome, a hallmark for a strict lesion in mitochondrial protein synthesis. The respiratory negative phenotype of mrf1 mutants lacking all known mitochondrial introns and the reduced synthesis of mitochondrial translation products encoded by unsplit genes confirm a primary defect in mitochondrial protein synthesis. Over-expression of the MRF1 gene in a mitochondrial nonsense suppressor strain reduces suppression in a dosage-dependent manner, shedding new light on the role of the '530 region' of 16S-like ribosomal RNA in translational fidelity.

Infected aneurysm of the abdominal aorta due to Listeria monocytogenes.

A 79-yr-old man was known for a year with a deteriorating clinical condition, vague abdominal complaints and an elevated erythrocyte sedimentation rate; he was afebrile. Extensive evaluation revealed no cause for his progressive disease. Eventually an infected aneurysm of the abdominal aorta was diagnosed, from which Listeria monocytogenes was cultured. After resection of the aneurysm the patient recovered initially very well. Regrettably, therapy-resistant chylous ascites developed, and the patient died due to surgical complications following a second laparotomy. Infected aortic aneurysms can present as an insidious disease, which may have catastrophic consequences if undiagnosed. A high index of suspicion is required to make a correct diagnosis. L. monocytogenes is an emerging, food-borne pathogen that can cause a wide spectrum of human diseases.

Familial IgG subclass imbalance, anti-SS-A antibodies and third-trimester foetal death.

Foetal heart block occurred in the second pregnancy of an apparently healthy 23-yr-old woman. Her mother and sister were known for 10 yr with hypergammaglobulinaemia which was due to a disproportionate polyclonal elevation of serum IgG1 and with a high titre of rheumatoid factors. No associated disease was obvious. A third-trimester foetal death had occurred with each of these patients. In the sera of these three women circulating anti-SS-A (Ro) antibodies were detected, which are known to be associated with congenital heart block. IgG subclass imbalance, consisting of a disproportionate polyclonal elevation of IgG1, has been recognised as being associated with a characteristic autoantibody pattern. Familial occurrence of this syndrome as such has hitherto not been reported.

Beware of the dog: meningitis in a splenectomised woman.

Purulent meningitis was diagnosed in a 75-yr-old splenectomised woman nine days after a dog bite. The original wound was apparently uninflamed. The causative microorganism proved to be a dysgonic fermenter 2 (DF-2) bacterium (renamed Capnocythophaga canimorsus). This is a recently recognised Gram-negative bacterium, belonging to the normal canine mouth flora, to which asplenic individuals seem to be particularly susceptible.

Pericardial fibrosis following busulfan treatment.

A case is reported of pericardial fibrosis after busulfan treatment in a man with chronic myeloid leukaemia. In the absence of any other explanation, we assume that busulfan may have been the cause of pericardial fibrosis in this patient. Other drugs causing pericardial fibrosis are discussed.

[Thrombocytopenia as the sole symptom of an HIV infection]. / Trombocytopenie als enig verschijnsel van HIV-infectie.

We report the case of a young adult who visited us because of thrombocytopenia and bleeding, clinically and cytologically compatible with autoimmune thrombocytopenic purpura (AITP). He was seropositive for HIV-1 and therefore HIV associated thrombocytopenia was diagnosed. Recent insights in the pathogenesis of this novel disease entity are discussed. The treatment is the classical AITP therapy. It is important, however, to refrain from therapy as long as possible, since a significant part of these patients improve spontaneously. We conclude that HIV associated thrombocytopenia will be increasingly important in the differential diagnosis of bleeding disorders.