Joseph R. Goodman

Hereditary macrothrombocytopathia, nephritis and deafness

Abstract Two unrelated families were studied in which two members of each have a syndrome of macrothrombocytopathia, nephritis and deafness. A third member of one family, a young child, has the platelet disorder and a mild hearing loss. The mode of inheritance of the syndrome appears to be dominant. Except for its severity in affected females, the renal disease is indistinguishable from the classic type of hereditary nephritis. Likewise, the high frequency sensorineural hearing loss is similar to that seen in Alports syndrome. The platelet disorder is characterized by thrombocytopenia, giant platelets with an abnormal ultrastructure, prolonged bleeding time and defective adherence of platelets to glass. Aggregation in response to collagen and epinephrine, and release of platelet factor 3 are impaired, and the release of nucleotide after exposure to collagen is abnormally low.

The Efficiency of the Translocation of Mycobacterium tuberculosis across a Bilayer of Epithelial and Endothelial Cells as a Model of the Alveolar Wall Is a Consequence of Transport within Mononuclear Phagocytes and Invasion of Alveolar Epithelial Cells

ABSTRACT The mechanism(s) by which Mycobacterium tuberculosis crosses the alveolar wall to establish infection in the lung is not well known. In an attempt to better understand the mechanism of translocation and create a model to study the different stages of bacterial crossing through the alveolar wall, we established a two-layer transwell system. M. tuberculosis H37Rv was evaluated regarding the ability to cross and disrupt the membrane. M. tuberculosis invaded A549 type II alveolar cells with an efficiency of 2 to 3% of the initial inoculum, although it was not efficient in invading endothelial cells. However, bacteria that invaded A549 cells were subsequently able to be taken up by endothelial cells with an efficiency of 5 to 6% of the inoculum. When incubated with a bicellular transwell monolayer (epithelial and endothelial cells), M. tuberculosis translocated into the lower chamber with efficiency (3 to 4%). M. tuberculosis was also able to efficiently translocate across the bicellular layer when inside monocytes. Infected monocytes crossed the barrier with greater efficiency when A549 alveolar cells were infected with M. tuberculosis than when A549 cells were not infected. We identified two potential mechanisms by which M. tuberculosis gains access to deeper tissues, by translocating across epithelial cells and by traveling into the blood vessels within monocytes.

Cardiac hypertrophy in rats with iron and copper deficiency: quantitative contribution of mitochondrial enlargement.

ExtractQuantitative studies of the ultrastructure of heart muscle in iron- and copper-depleted rats show an increased mitochondrial area that contributes to cardiac hypertrophy in both conditions. The mean ratios of mitochondrial/myofibrillar areas are 1.73 and 1.69, respectively, in the deficient groups compared with 0.70 in control animals. The markedly enlarged mitochondria appear to displace and distort the myofibrils. After iron-deficient rats are provided with iron, the reversal of the abnormal mitochondrial/myofibrillar ratio and of cardiac hypertrophy requires about 16 days or approximately twice as long as the complete repair of anemia.In heart muscle from iron-deficient animals, the mitochondrial cytochromes, which all contain iron, remain essentially normal in concentration. In the copper-deficient rats, in contrast, cytochrome a+a3, which contains copper, is depressed to less than one-half the normal concentration. Isolated mitochondria from heart and liver of all animals deficient in iron and copper function normally with respect to respiration and phosphorylation. Thus, a correlation between abnormality of mitochondrial structure, composition, and function is not as yet apparent.The mitochondrial contribution to the cardiac hypertrophy of iron and copper deficiency cannot be attributed entirely to increased work load secondary to anemia, particularly in copper-deficient rats whose cardiac enlargement precedes the development of anemia. The morphologic changes are distinct from those observed in experimental work hypertrophy and can represent a response to the lack of essential precursors required for the cytochromes or other mitochondrial constituents.Speculation: Cardiac hypertrophy in iron and copper deficiency is in part attributable to enlargement of the mitochondrial compartment. This results from the lack of trace metals required for the production of cytochromes or other mitochondrial constituents.

Mycobacterium avium Invades the Intestinal Mucosa Primarily by Interacting with Enterocytes

ABSTRACT Previous studies have demonstrated that Mycobacterium avium can invade intestinal epithelial cells both in vitro and in vivo. When given to mice orally, M. aviumpreferentially interacts with the intestinal mucosa at the terminal ileum. We evaluated the mechanism(s) of M. avium binding and invasion of the intestinal mucosa using three different systems: (i) electron microscopy following administration of M. avium into an intestinal loop in mice, (ii) quantitative comparison of the bacterial load in Peyers patch areas of the terminal ileum versus areas that do not contain Peyers patches, and (iii) investigation of the ability of M. avium to cause disseminated infection following oral administration using B-cell-deficient mice, lacking Peyers patches, in comparison with C57BL/6 black mice. By all approaches, M. avium was found to invade the intestinal mucosa by interacting primarily with enterocytes and not with M cells.

Interaction of Mycobacterium avium with human monocyte-derived dendritic cells

ABSTRACT The mechanism by which mycobacteria elicit class I-restricted T-cell responses remains undefined because these organisms have been shown to reside exclusively within membrane-bound vesicles in macrophages (Mφ), their primary host cells. We studied the interaction of M. avium with dendritic cells (DC) because they are the most potent antigen-presenting cells and are abundant atM. avium infection sites. We observed that both DC and Mφ, generated from human peripheral blood monocytes by short-term culture, internalized M. avium. The onset of programmed cell death and the percentage of apoptotic cells in infected DC and Mφ were comparable. However, following infection, DC secreted significantly larger amounts of interleukin-12, but not interleukin-1β, than infected autologous Mφ. Further analysis of infected cells showed that while phagosomes failed to acidify in bothM. avium-infected DC and Mφ, bacilli grew more slowly in DC. Electron microscopy studies revealed that M. aviumresided within endocytic vacuoles in both cell types. The vacuolar membrane surrounding some bacilli in approximately 10% of the vacuoles in DC possessed several breaks. The importance of this finding will have to be addressed in future studies.

Mycobacterium avium enters intestinal epithelial cells through the apical membrane, but not by the basolateral surface, activates small GTPase Rho and, once within epithelial cells, expresses an invasive phenotype

Mycobacterium avium is a common pathogen in AIDS patients that is primarily (but not exclusively) acquired through the gastrointestinal tract, leading to the development of bacteraemia and disseminated disease. To cause infection through the gut, binding and invasion of the intestinal epithelial barrier are required. To characterize this process further, we determined the cell surface(s) (basolateral vs. apical membrane) that M. avium interacts with in intestinal mucosal cells in vitro. The level of binding and invasion of both HT‐29 and Caco‐2 intestinal cell monolayers by M. avium were similar when the assay was performed with control medium in the presence of Ca2+ (when only the apical surface was exposed), with Ca2+‐depleted medium or with Ca2+‐depleted medium + 1 mM EGTA (exposure of both apical and basolateral membranes), suggesting that the bacterium enters the apical surface of the epithelial lining. These observations were confirmed by assays in a transwell system and by using fluorescent microscopy. Real‐time video microscopy showed that M. avium entry was not associated with membrane ruffling and the use of pharmacological inhibitors of the small GTPases demonstrated that M. avium invasion is dependent on the activation of the small GTPases Rho, but not on Rac or Cdc42. Passage of M. avium through HT‐29 cells led to a phenotypic change (intracellular growth; IG) that was associated with a significantly greater (between five‐ and ninefold) ability to bind to and invade new monolayers of epithelial cells or macrophages when compared with the invasion by M. avium grown on agar (extracellular growth; EG). IG phenotype invasion of HT‐29 cells also takes place only by the apical surface. M. avium enters intestinal epithelial cells by the apical surface and, once within the cells, changes phenotype, becoming more invasive towards both macrophages and other epithelial cells.

Mycobacterium avium infection of gut mucosa in mice associated with late inflammatory response and intestinal cell necrosis

Mycobacterium avium is an intracellular pathogen that is associated with disseminated infection in acquired immunodeficiency syndrome (AIDS). Patients with AIDS appear to acquire M. avium mainly through the gastrointestinal tract. Previous studies have shown that healthy mice given M. avium orally develop disseminated infection after 2-4 weeks. The chief site of M. avium invasion of the intestinal mucosa is the terminal ileum. To learn more about the pathophysiology of M. avium infection of the intestinal mucosa, C57BL/6 bg+ bg+ mice were infected orally with M. avium strain 101 and groups of six mice were killed each week for 8 weeks. The terminal ileum was then prepared for histopathological studies and electron microscopy. A delayed inflammatory response was observed and influx of neutrophils in the Peyers patches was the only abnormality seen at 1 week. A severe inflammatory response was seen from week 2 to week 5 and necrosis of intestinal villi was observed 6 weeks after infection. These results indicate that invasion and infection of the normal intestine by M. avium results in a severe inflammatory response with segmental necrosis of the intestinal mucosa.

Reye's syndrome in twins

Acute encephalopathy with visceral fatty infiltration (Reyes syndrome) in twins, one of whom survived, afforded the opportunity to study the condition in vivo. Electron microscopic findings suggested that a reversible hepatic lesion was insolved in the pathogenesis; infection with herpes simplex may have been the immediate cause of the disease. An unusual enzyme profiel facilitated the diagnosis.

Antibiotic-Associated Interstitial Nephritis and Nephrotic Syndrome

The combination of interstitial nephritis and minimal-change nephrotic syndrome has been well described in adults receiving nonsteroidal anti-inflammatory agents. The association of interstitial nephritis and minimal-change nephrotic syndrome has recently been described in 1 adult patient receiving ampicillin and in 1 patient receiving rifampin. We describe an 8-month-old child who developed reversible interstitial nephritis and minimal-change nephrotic syndrome while taking antibiotics.

Primary Intestinal Lymphangiectasia

A 16-year-old boy with primary intestinal lymphangiectasia presented with peripheral edema of 6 weeks duration. Laboratory and radiological studies included absolute lymphopenia, hypoalbuminemia, stea