Pneumococcal endocarditis in Alaska natives. A population-based experience, 1978 through 1990.

BACKGROUND: Streptococcus pneumoniae is an uncommon cause of infective endocarditis (IE). We studied the presentation, microbiologic characteristics, and outcome of nine cases of S pneumoniae IE during a 12 1/2-year period in a population of 75,000 indigenous Alaska Natives (ANs), who have documented high rates of invasive pneumococcal disease. METHODS: Fifty-six cases of IE occurred in ANs statewide during 1978 through 1990. Medical records of all nine confirmed cases of S pneumoniae IE were reviewed. Incidence rates for S pneumoniae IE and all IE were calculated. RESULTS: Alaska Natives experience S pneumoniae IE as a fulminant illness, with acute aortic valve insufficiency (100%) frequently requiring emergent valve replacement, S pneumoniae meningitis (56%), and death (33%). No patient with S pneumoniae IE had known preexisting heart disease, and the most common underlying disease was alcoholism (56%). Pneumonia was diagnosed and embolic complications were suspected in 33%. All five S pneumoniae isolates examined were penicillin sensitive and were of serotypes included in the pneumococcal vaccine. Pneumococcal IE accounted for 15.8% of all IE diagnosed in ANs. Age- and sex-adjusted incidence rates for IE of all causes and S pneumoniae IE were 8.5 and 1.5 per 10(5) persons per year, respectively. During 1986 through 1988, 4.3% of AN adults diagnosed with S pneumoniae bacteremia developed S pneumoniae IE. CONCLUSIONS: Pneumococcal endocarditis in all but one AN case required emergent valve replacement and had a 33% mortality. The annual incidence rate of S pneumoniae IE in this population was five to 37 times higher than contemporary rates elsewhere. Increased efforts to prevent pneumococcal disease in ANs appear warranted. Clinicians everywhere should anticipate the possible development of S pneumoniae IE in adult patients with pneumococcal sepsis, especially with meningitis, even with previous vaccination and prompt adequate antimicrobial therapy.

The immunocytochemical localization of enkephalin in the central nervous system of the rat.

The immunocytochemical localization of enkephalin-like immunoreactivity (ELI) throughout the rat central nervous system (CNS) was investigated. The detection of ELI-containing structures was facilitated through the use of (1) brains from colchicine-treated rats, (2) the proteolytic pretreatment of sections with pronase and (3) the "double-bridge" staining technique. Our findings confirm the presence of ELI in perikarya, neuronal processes and terminals in many areas of the CNS. In addition, the localization of ELI-containing perikarya is reported for the first time in the following areas: the olfactory bulb, the olfactory tubercle, the lateral preoptic nucleus, several nuclei within the amygdaloid nuclear complex, the hippocampus, the neocortex, the cingulate cortex, the posterior mammillary nucleus, the medial nucleus of the optic tract, the brachium of the inferior colliculus, the ventral tegmental nucleus, the locus ceruleus, the sub-ceruleal region, the lateral trapezoid nucleus, the nucleus reticularis lateralis, and lamina VII of the cervical spinal cord. Our results demonstrate ELI in neurons which are heterogeneous in size, some probably functioning as interneurons and others as projection neurons in different areas of the CNS. The location of these neurons within the brain suggests that these pentapeptides serve diverse functions which include, in addition to nociception, the regulation of neuroendocrine, respiratory, auditory, vestibular, and olfactory functions.

Autoantibodies in paraneoplastic cerebellar degeneration bind to cytoplasmic antigens of Purkinje cells in humans, rats and mice and are of multiple immunoglobulin classes.

Purkinje cell autoantibodies in sera of six female patients with paraneoplastic cerebellar degeneration (PCD) were investigated by indirect immunofluorescence for immunoglobulin isotype and species specificity. Four patients had gynecologic cancer, one breast cancer and one lymphoma. Control sera from 125 patients were negative for Purkinje cell antibodies of IgG, IgM and IgA isotypes. These included neurologically normal cancer patients, cancer patients with paraneoplastic syndromes not involving the cerebellum and patients with non-neoplastic neurologic disorders. IgG antibodies in the six PCD sera bound to discrete cells in the cerebellum of human, rat and mouse (titers 1000-128,000). Antibodies of IgM class were additionally found in two sera (titers 100 and 500) and IgA in a third serum (titer 1000). Antibodies of each isotype gave a similar staining pattern, highlighting the cytoplasm of Purkinje cells in a coarse granular pattern, and the peripheral cytoplasm of discrete molecular layer cells. Antibodies of IgE class were not found. Rodent cerebellar tissue was found to be a useful substitute for human tissue in clinical testing for Purkinje cell antibodies, and has the advantage of being readily available in highly viable state. Its use should facilitate further characterization of the autoantigen(s) of PCD, and possibly the development of an animal model involving passive transfer of immunoglobulins. Screening for IgM and IgA Purkinje cell antibodies in addition to IgG may increase the yield of positive results in clinical serological testing.

Transmitter diversity in carotid body afferent neurons: dopaminergic and peptidergic phenotypes.

Hypoxic stimulation of carotid body chemoreceptors is conveyed to the brainstem by primary sensory neurons whose peripheral axons run in the carotid sinus nerve. While considerable attention has focused on defining chemical neuroregulators released by glomus cells in the carotid body, our understanding of the morphology, distribution and transmitter phenotype of these carotid body afferent neurons remains limited. Carotid body afferent neurons were labeled by microinjection of the retrograde tracer, Fluorogold, into the vascularly isolated rat carotid body. In addition, immunoelectron microscopy was used to correlate transmitter phenotype with ultrastructural features of afferent terminals in the carotid body. Our results indicate that 41% of all carotid body afferent neurons express tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, whereas 7% contain substance P. Tyrosine hydroxylase- and substance P-positive neurons constitute separate subpopulations of carotid body afferents, as these two phenotypes were not colocalized. Most of the tyrosine hydroxylase-containing carotid body afferent neurons were small- or medium-sized (mean cell diameter 15-20 microns) and located in the distal petrosal ganglion, whereas the majority of substance P-containing carotid body afferent neurons were medium- to large-sized (mean cell diameter 20-29 microns) and located in the proximal petrosal ganglion and jugular ganglion. These differences strengthen the notion that these catecholaminergic and peptidergic carotid body afferent neurons give rise to functionally distinct subsets of chemoafferent fibers. To further characterize the catecholaminergic phenotype expressed by tyrosine hydroxylase-positive cells in the petrosal ganglion, we examined the colocalization of tyrosine hydroxylase and DOPA decarboxylase, the dopamine-synthesizing enzyme. Eighty-six per cent of tyrosine hydroxylase-positive neurons in the distal petrosal ganglion also contained DOPA decarboxylase; as these cells do not express the norepinephrine-synthesizing enzyme, dopamine beta-hydroxylase, these data indicate that the catecholaminergic carotid body afferent neurons are dopaminergic. Finally, ultrastructural analysis of the peripheral processes of tyrosine hydroxylase-positive afferent terminals in the carotid body demonstrated endings in close opposition to Type I glomus cells, consistent with a role for dopaminergic afferent neurons in carotid body chemoreception. One possibility is that these cells, in addition to their role as afferents, constitute a morphologic substrate for dopaminergic "efferent" inhibition in the carotid body.

Galanin expression in carotid body afferent neurons.

The present study examined expression and plasticity of the neuropeptide, galanin, in carotid body afferent neurons in the petrosal ganglion of the adult rat. The pattern of galanin expression was compared with that of tyrosine hydroxylase, a selective marker of dopaminergic carotid body afferents in the petrosal ganglion. In normal animals, only 3% of tyrosine hydroxylase-containing petrosal ganglion neurons co-expressed galanin. Retrograde labeling studies, in which FluoroGold was injected into the vascularly isolated carotid body, demonstrated that all tyrosine hydroxylase-positive-galanin-positive cells in the petrosal ganglion project to this target. In addition, however, we unexpectedly found that galanin expression was markedly increased in the petrosal ganglion following FluoroGold injection into the carotid body. On the other hand, tyrosine hydroxylase expression was unchanged, indicating that monoaminergic and peptidergic traits can be differentially regulated in these cells. In summary, these data demonstrate that monoaminergic chemoafferent neurons can co-express a peptidergic trait, similar to catecholaminergic neurons within the central and autonomic nervous systems, and that these cells retain the potential for phenotypic plasticity in adulthood.

The central organization of carotid body afferent projections to the brainstem of the rat.

Despite increasing focus on brainstem respiratory control mechanisms in the rat, relatively little is known about the central organization of chemoreceptor pathways in this species. To approach this issue, the present study sought to selectively define the central projections of primary sensory neurons that innervate the carotid body. Afferent projections were visualized by horseradish peroxidase histochemistry following microinjection of wheat germ agglutinin-horseradish peroxidase into the vascularly isolated carotid body in situ. Labeled afferent fibers were found in several discrete regions of the dorsomedial and ventrolateral medulla. Heaviest labeling was seen bilaterally in the commissural and medial subnuclei of the caudal nucleus tractus solitarius (nTS); more moderate labeling was found bilaterally in the intermediate, interstitial, and dorsolateral subnuclei and ipsilaterally in the ventrolateral subnuclei. In addition, we observed a prominent projection to the caudal ventrolateral medulla in the region of the nucleus retroambigualis. Sparse labeling was also seen in the dorsal motor nucleus of the vagus nerve and the area postrema. These findings support the existence of multiple pathways by which peripheral chemoreceptor inputs may influence central respiratory neurons. In addition to the classically defined relay in nTS, carotid body afferents may also interact more directly with respiratory- or cardiovascular-related neurons in other regions such as the ventrolateral medulla.

Leiomyoma of the nasal septum.

Leiomyoma is a benign myogenic tumor that may develop wherever smooth muscle is present. It occurs commonly in the uterus, skin, and gastrointestinal tract and is rare within the nasal cavity. Only three of twenty-four reported cases of sinonasal leiomyoma have been found to originate from the nasal septum. Treatment of choice for these neoplasms is surgical excision. We present two cases of nasal septal leiomyoma. Unique features discussed include recurrence of one neoplasm and the technique used to endoscopically repair a cerebrospinal fluid leak resulting from resection of the neoplasm.

Criteria of reliability for light microscopic immunocytochemical staining.

The following criteria of reliability are defined and discussed for immunocytochemical staining at the light microscopical level: efficiency, accuracy, precision, sensitivity, and specificity. Whenever practical, tests are suggested for obtaining information on the extent to which these criteria are fulfilled in a given system, and procedures are outlined for improving immunocytochemical staining in terms of these criteria. It is suggested that consideration of reliability criteria will help investigators in their choice of methodology, design of experimental strategy, and valid interpretation of the results.

Immunocytochemical localization of beta-endorphin-containing neurons in the rat brain.

beta-Endorphin-containing neurons in the rat central nervous system were localized using three improvements of the unlabelled antibody-enzyme bridge immmunocytochemical technique. These improvements were (1) the use of brains from colchicine-treated rats; (2) the proteolytic pretreatment of sections with pronase, and (3) a 'double-bridge' staining procedure. In addition to the known localization of beta-endorphin-like immunoreactivity in perikarya in the medial basal hypothalamus, we have observed nerve fibers and terminals with beta-endorphin-like immunoreactivity to be more widely distributed than reported in previous studies. This includes discrete areas of the septal, preoptic, hypothalamic, thalamic and subthalamic regions, the amygdala, the periaqueductal gray, the inferior colliculus, the nucleus tegmenti pontis, the nucleus raphe dorsalis, several regions of the reticular formation, the locus ceruleus, the parabrachial nuclei, the mesencephalic trigeminal nucleus, the nucleus raphe magnus, the solitary tract and the nucleus of the solitary tract. The distribution of beta-endorphin-like immunoreactivity is in good agreement with many of the physiological, neuroendocrine and behavioral effects attributed to this peptide such as analgesia, the regulation of the release of pituitary hormones, thermoregulation and feeding behavior. This implicates beta-endorphin as an important neurotransmitter or modulator with specific functions within the central nervous system.

BDNF supports mammalian chemoafferent neurons in vitro and following peripheral target removal in vivo.

Chemoreceptor neurons innervating the rat carotid body were used as a model system to define target regulation of visceral sensory development in fetal and newborn animals. In vitro, chemoafferents were selectively supported by coculture with the carotid body or by treatment with trkB ligands [brain-derived neurotrophic factor (BDNF) and neurotrophin-4], whereas nerve growth factor and neurotrophin 3 had no effect. In vivo, chemoafferent neurons died following carotid body removal at birth, indicating a predominant role of peripheral, rather than central, targets in mediating survival at this stage. However, in the absence of target tissues, a large proportion of carotid body afferents could be rescued by implants containing BDNF. Moreover, BDNF mRNA was detected in the newborn carotid body by reverse transcriptase polymerase chain reaction. These data provide the first demonstration that BDNF can substitute for peripheral target support of sensory neuron survival in vivo and indicate that trkB ligands may be particularly important for development of visceral afferents involved in cardiorespiratory control.

Somatostatin-containing neurons in the rat brain: widespread distribution revealed by immunocytochemistry after pretreatment with pronase.

Immunocytochemical staining after controlled proteolytic treatment of the sections with pronase revealed widespread distribution of neuronal cell bodies with somatostatin-like immunoreactivity (SLI) in the rat forebrain. SLI-positive neurons were found in regions of the neocortex, the pyriform cortex, the cingulate cortex, the striatum, the olfactory tract and tubercle, the nucleus accumbens, the septum, and the hypothalamus. These results are consistent with previous radioimmunoassay findings and suggest the presence of large somatostatin-like (possibly precursor) molecules in the neurons stained for SLI after pronase treatment.

Confirmed previous infection with Chlamydia pneumoniae (TWAR) and its presence in early coronary atherosclerosis.

BACKGROUND: Chlamydia pneumoniae has been identified in coronary atheroma, but concomitant serum antibody titers have been inconsistently positive and unavailable before the detection of early or advanced atherosclerotic lesions. METHODS AND RESULTS: This retrospective investigation was performed on premortem serum specimens and autopsy tissue from 60 indigenous Alaska Natives at low risk for coronary heart disease, selected by the potential availability of their stored specimens. Serum specimens were drawn a mean of 8.8 years (range, 0.7 to 26.2 years) before death, which occurred at a mean age of 34.1 years (range, 15 to 57 years), primarily from noncardiovascular causes (97%). Coronary artery tissues were independently examined histologically and, for C pneumoniae organism and DNA, by immunocytochemistry (ICC) and polymerase chain reaction (PCR) with species-specific monoclonal antibody and primers. Microimmunofluorescence detected species-specific IgG, IgA, and IgM antibody in stored serum. C pneumoniae, frequently within macrophage foam cells, was identified in coronary fibrolipid atheroma (raised lesions, Stary types II through V) in 15 subjects (25%) and early flat lesions in 7 (11%) either by PCR (14, 23%) or ICC (20, 33%). The OR for C pneumoniae in raised atheroma after a level of IgG antibody > or =1:256 >8 years earlier was 6.1 (95% CI, 1.1 to 36.6) and for all coronary tissues after adjustment for multiple potential confounding variables, including tobacco exposure, was 9.4 (95% CI, 2.6 to 33.8). CONCLUSIONS: Serological evidence for C pneumoniae infection frequently precedes both the earliest and more advanced lesions of coronary atherosclerosis that harbor this intracellular pathogen, suggesting a chronic infection and developmental role in coronary heart disease.