ABSTRACT The results for 6,532 consecutive mycobacterial respiratory specimens collected from 1,040 patients from 1993 to 1995 in a Texas hospital were studied to determine the sensitivity of fluorescence microscopy for detection of Mycobacterium tuberculosis and nontuberculous mycobacteria (NTM). Smears were positive for acid-fast bacilli (AFB) in 63% (677 of 1,082) of specimens growing M. tuberculosis and 56% (638 of 1,148) of specimens growing the four most common species of NTM. Smear positivity by species was 58% (446 of 776) for M. avium complex, 51% (154 of 300) for rapidly growing mycobacteria (98% were M. abscessus ), 78% (29 of 37) for M. kansasii , and 26% (9 of 35) for M. gordonae . Definite or probable disease by clinical criteria was present in 79% of patients with M. avium complex, 93% of patients with rapidly growing mycobacteria, 100% of patients with M. kansasii , and 0% of patients with M. gordonae . Patients with M. avium complex had a low incidence of AIDS (7%), and approximately 50% of non-AIDS patients had upper-lobe cavitary disease and 50% had nodular bronchiectasis. Only 23 of 6,532 (0.35%) of AFB smears were positive with a negative culture excluding patients on therapy for established mycobacterial disease. These studies suggest that NTM are as likely as M. tuberculosis to be detected by fluorescent microscopy in specimens from patients from areas endemic for NTM lung disease and at low risk for AIDS.

We analyzed the effects of two growth factors that regulate oligodendrocyte progenitor (O-2A) development on the expression of glutamate receptor (GluR) subunits in cortical O-2A cells. In the absence of growth factors, GluR1 was the AMPA subunit mRNA expressed at the lowest relative level. Basic fibroblast growth factor (bFGF) caused an increase in GluR1 and GluR3 steady-state mRNA levels. Platelet-derived growth factor (PDGF) did not modify the mRNA levels for any of the AMPA subunits but selectively potentiated the effects of bFGF on GluR1 mRNA (4.5-fold increase). The kainate-preferring subunits GluR7, KA1, and KA2 mRNAs were increased by bFGF, but these effects were not modified by cotreatment with PDGF. Nuclear run-on assays demonstrated that PDGF+bFGF selectively increased the rate of GluR1 gene transcription (2.5-fold over control). Western blot analysis showed that GluR1 protein levels were increased selectively (sixfold over control) by PDGF+bFGF. Functional expression was assessed by rapid application of AMPA to cultured cells. AMPA receptor current densities (pA/pF) were increased nearly fivefold in cells treated with PDGF+bFGF, as compared with untreated cells. Further, AMPA receptor channels in cells treated with PDGF+bFGF were more sensitive to voltage-dependent block by intracellular polyamines, as expected from the robust and selective enhancement of GluR1 expression. Our combined molecular and electrophysiological findings indicate that AMPA receptor function can be regulated by growth factor-induced changes in the rate of gene transcription.

We have analyzed the role of glutamate and its receptors (GluRs) in regulating the development of oligodendrocytes. Activation of AMPA- preferring GluRs with selective agonists inhibited proliferation of purified cortical oligodendrocyte progenitor (O-2A) cells cultured with different mitogens, as measured by [3H]thymidine incorporation or bromodeoxyuridine staining. In contrast, activation of GABA or muscarinic receptors did not affect O-2A proliferation. Cell viability and apoptosis assays demonstrated that the inhibition of O-2A proliferation was not attributable to a cytotoxic action of GluR agonists, and was reversible. Activation of GluRs prevented lineage progression from the O-2A (GD3+/nestin+) stage to the prooligodendroblast (O4+) stage, but did not affect O-2A migration. Additional experiments examined the membrane ionic channels mediating these GluR activation effects. We found that proliferating O-2A cells expressed functional delayed rectifier K+ channels, which were absent in pro-oligodendroblasts. GluR agonists and the K+ channel blocker tetraethylammonium (TEA) strongly inhibited delayed rectifier K+ currents in O-2A cells. TEA reproduced the effects of GluR activation on O-2A proliferation and lineage progression in the same concentration range that blocked delayed rectifier K+ currents. These results indicate that glutamate regulates oligodendrogenesis specifically at the O-2A stage by modulating K+ channel activity.

An 8-year old girl was infected for a second time with Salmonella typhi by contact with her grandmother, a known typhoid carrier. The S. typhi from both patient and grandmother had closely related genomic pulsed field gel electrophoresis patterns that differed from epidemiologically unrelated strains. The girl responded well to a 14-day course of oral trimethoprimsulfamethoxazole. The grandmother was treated successfully with a 28-day regimen of oral ciprofloxacin. Typhoid fever remains an endemic disease in the United States, largely because of recognized chronic stool carriers. Most of these carriers had typhoid in the preantibiotic era and remain potential sources of disease when they provide meals for others, not uncommonly grandchildren. The importance of this "grandmother" connection to endemic typhoid fever is reviewed, as is the potential use of pulsed field gel electrophoresis pattern analysis for comparison of strains of S. typhi.

An 8-year-old girl was infected for a second time with Salmonella typhi by contact with her grandmother, a known typhoid carrier. The S. typhi from both patient and grandmother had closely related genomic pulsed field gel electrophoresis patterns that differed from epidemiologically unrelated strains. The girl responded well to a 14-day course of oral trimethoprim-sulfamethoxazole. The grandmother was treated successfully with a 28-day regimen of oral ciprofloxacin. Typhoid fever remains an endemic disease in the United States, largely because of recognized chronic stool carriers. Most of these carriers had typhoid in the preantibiotic ear and remain potential sources of disease when they provide meals for others, not uncommonly grandchildren. The importance of this "grand-mother" connection to endemic typhoid fever is reviewed, as is the potential use of pulsed field gel electrophoresis pattern analysis for comparison of strains of S. typhi.

mRNAs for AMPA- and kainate-preferring glutamate receptor subunits are expressed abundantly in the CNS, yet functional studies of neurons and glia from brain suggest selective expression of AMPA receptors. We now show that glial cells of the O-2A lineage express rapidly desensitizing responses to kainate, mRNAs for GluR6, GluR7, KA-1, and KA-2, rapidly desensitizing responses to AMPA, and mRNAs for GluR-B, -C, and -D. Analysis of glutamate receptor currents in single cells reveals two receptor populations with high and low affinity for kainate and different sensitivity for potentiation by concanavalin A and for block of desensitization by cyclothiazide. Our experiments describe the characterization of native kainate-preferring receptors in glia and reveal coexpression in single cells of functional AMPA- and kainate-preferring receptors.

purpose: We studied the clinical and laboratory findings of patients with pneumonia due to Moraxella (Branhamella) catarrhalis to better characterize the types of patients who develop this pneumonia, the clinical features of the illness, and the type of and response to drug therapy, as well as the immediate and long-term survival of these patients.