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J T Weber

Publications and source records attributed to J T Weber.

At least 37 records · Page 2Linked to original sources
PubMed1995

The first reported outbreak of diarrheal illness associated with Cyclospora in the United States.

OBJECTIVE: To investigate and characterize the epidemiology of a diarrheal outbreak associated with a potentially new pathogen, Cyclospora species (previously referred to as Cyanobacteria [blue-green algae]-like bodies). DESIGN: Three retrospective cohort studies supported by laboratory studies, environmental investigation, and community surveillance. SETTING: A hospital in Chicago. PARTICIPANTS: Housestaff physicians and hospital administrative staff. MEASUREMENTS: Identification of clinical features associated with illness and potential risks for acquisition of infection. RESULTS: Illness was characterized by watery diarrhea, abdominal cramping, decreased appetite, and low-grade fever. Symptoms typically occurred in a distinctive cycle of remissions and exacerbations lasting up to several weeks. Stool cultures and examinations for known ova and parasites were negative. Microscopic examination of stool specimens from 11 ill persons showed many spherical bodies, 8 to 10 microns in diameter, that were identified as Cyclospora organisms. The organisms disappeared by 9 weeks after onset of illness in the 7 patients from whom follow-up specimens were obtained. Epidemiologic studies implicated tap water from a physicians' dormitory as the most likely source of the outbreak. Environmental investigation suggested that stagnant water in a storage tank may have contaminated the water supply after a pump failure. CONCLUSIONS: This is the first reported outbreak of diarrhea associated with Cyclospora in the United States. Cyclospora may be a human enteric pathogen able to produce bouts of acute and relapsing diarrhea, and it should be considered in assessments of patients with unexplained, prolonged diarrheal illness.

Adult↗
PubMed1995

New treatments for Chlamydia trachomatis genital infection.

To provide information for the formulation of treatment guidelines, we review recently published articles and abstracts on advances in the treatment of Chlamydia trachomatis genital infection. We ask specific questions about new treatments that are answered on the basis of the results of clinical trials and efficacy studies. New, potentially effective treatments for C. trachomatis genital infection include azithromycin and ofloxacin. Clinical studies indicate that the efficacy of these agents is equivalent to that of the current recommended agent doxycycline. Both azithromycin and ofloxacin are substantially more expensive than doxycycline. Azithromycin has the advantage of being given as a single dose, while doxycycline and ofloxacin are administered for 1 week. Issues of compliance, cost, and toxicity for specific patients should be considered when deciding whether to treat C. trachomatis genital infections with these agents.

Azithromycin↗
PubMed1994

Synaptic morphology of substance P terminals on catecholamine neurons in the commissural subnucleus of the nucleus tractus solitarii in the rat.

The ultrastructure of substance P-containing nerve terminals synapsing on catecholamine neurons in the rat commissural subnucleus of the nucleus tractus solitarii (NTScom) was studied using a double immunocytochemical labeling technique. Although there were numerous tyrosine hydroxylase-immunoreactive (TH-I) somata present, substance P immunoreactive (SP-I) cell bodies were only occasionally found in the NTScom. At the light microscopic level, many SP-I terminals were seen closely associated with TH-I dendrites and somata. At the electron microscopic level, SP-I terminals synapsing on TH-I structures were also readily encountered. SP-I terminals contained small, clear, and predominantly spherical vesicles (32 +/- 4 nm diameter), as well as large dense-cored vesicles approximately 100 nm in diameter. Postsynaptic TH-I dendritic profiles of various calibers and somata were encountered. These postsynaptic TH-I structures often showed postsynaptic densities. The morphological features of the SP-TH synapses in the present study, that is, the size of synaptic vesicles and the presence of postsynaptic densities, are quite different from those of central carotid sinus afferent synapses reported in our previous study [Chen et al. (1992), J. Neurocytol., 21:137-147]. Therefore, most of the SP terminals of the SP-TH synapses in the NTScom appear not to originate from the carotid sinus afferents. SP-I second-order neurons of the carotid sinus afferent pathway [Chen et al. (1991), J. Auton. Nerv. Syst., 33:97-98] may be one of the possible sources of such terminals.

Afferent Pathways↗
PubMed1994

Wound botulism.

Explore the source record for details and available documents.

Botulism↗
PubMed1994

Cholera in the United States, 1965-1991. Risks at home and abroad.

OBJECTIVE: To assess risks for cholera in the United States. DESIGN: Review of published reports of cholera outbreaks and sporadic cases and Centers for Disease Control and Prevention (CDC) memoranda and laboratory reports. PATIENTS: Persons with symptomatic laboratory-diagnosed cholera treated in the United States and territories. RESULTS: From 1965 through 1991, 136 cases of cholera were reported. Fifty-three percent of the patients were hospitalized and three persons died (case-fatality rate, 0.02). Ninety-three infections were acquired in the United States and 42 overseas; for one case the source was unknown. Domestically acquired cholera was largely related to the endemic Gulf Coast focus of Vibrio cholerae 01 (56 cases). The major domestic food vehicle was shellfish, particularly crabs harvested from the Gulf of Mexico or nearby estuaries. In 1991, 14 (54%) of 26 domestically acquired cases were caused by food from Ecuador (n = 11) and Thailand (n = 3). During 1991, the first cases of cholera in travelers returning from South America were reported. In 1991, the rate of cholera among air travelers returning from South America was estimated as 0.3 per 100,000; among air travelers returning from Ecuador, 2.6 per 100,000. CONCLUSIONS: Cholera remains a small but persistent risk in the United States and for travelers. An endemic focus on the Gulf Coast, the continuing global pandemic, and the epidemic in South America make this likely to continue for years to come. Physicians should know how to diagnose and treat cholera and should report all suspected cases to their state health departments.

Adolescent↗
PubMed1994

Synaptic connections of central carotid sinus afferents in the nucleus of the tractus solitarius of the rat. II. Connections with substance P-immunoreactive neurons.

A combined transganglionic transport and immunocytochemical technique was used to study the synaptic morphology of central carotid sinus afferents and substance P-immunoreactive neurons in the commissural subnucleus of the nucleus of the tractus solitarius in rats. A large population of substance P-immunoreactive neurons (88.32%) were seen in close association with central carotid sinus afferents by light microscopy. However, many labelled central carotid sinus afferents appeared not associated with substance P-immunoreactive neurons in the nucleus of the tractus solitarius. Substance P-immunoreactive neurons were spindle, pear, or oval-shaped with a short axis ranging from 5 to 11 microns. Their long axis was oriented predominantly in a lateral-medial direction along the path of the central carotid sinus afferents from the solitary tract to the midline. Synaptic contacts between central carotid sinus afferents and substance P-structures, including dendritic profiles of different calibers and somas, were readily found by electron microscopy. Many central carotid sinus afferents were also found in synaptic contact with non-immunoreactive dendrites and somas. Appositions between central carotid sinus afferents and unlabelled axon terminals were common, but only in a few cases were morphological manifestations of synapses revealed. In the latter, the substance P-immunoreactive terminals appeared mostly presynaptic but postsynaptic ones were also encountered. Our data provide the evidence that some of the substance P-immunoreactive cells in the nucleus of the tractus solitarius are 2nd order neurons of the carotid sinus afferent pathway. The possibility that some of the substance P-immunoreactive neurons in the nucleus of the tractus solitarius may be interneurons and mediate carotid sinus afferent inputs to catecholaminergic neurons in the nucleus of the tractus solitarius is considered. Our findings also provide an anatomical substrate for a possible presynaptic modulatory role of central carotid sinus afferents on the inputs from other brain centers to the substance P-neurons in the nucleus of the tractus solitarius.

Afferent Pathways↗
PubMed1994

The neurotrophins and their receptors: structure, function, and neuropathology.

The neurotrophins are a family of polypeptides that promote differentiation and survival of select peripheral and central neurons. Nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, neurotrophin-4, and neurotrophin-5 are included in this group. In recent years, tremendous advances have been made in the study of these factors. This has stimulated our review of the field, characterizing the neurotrophins from initial isolation to molecular analysis. The review also discusses their synthesis, localization, and responsive tissues, in both the periphery and CNS. The complex receptor interactions of the neurotrophins are also analyzed, as are putative signal transduction mechanisms. Discussion of the observed and postulated involvement in neuropathological disorders leads to the conclusion that the neurotrophins are involved in the function and dysfunction of the nervous system.

Animals↗
PubMed1994

The opiate system in invertebrates.

The presence in diverse species of a similar mode of communication, that of a soluble messenger binding to a receptor, raises the question as to whether the specific components of this system are equally widespread. Do invertebrates use the same hormones and receptors as vertebrates do? Invertebrates ranging from unicellular organisms to insects have been shown to contain opiate-like peptides and binding sites, and they exhibit biological responses to opiates. However, critical genetic data are lacking. It is not known how signal systems arise phylogenetically, but it is conceivable that signal molecules that are already present cause the formation of their own receptors from membrane proteins.

Animals↗
PubMed1994

Epidemic cholera in Ecuador: multidrug-resistance and transmission by water and seafood.

To determine risk factors for cholera in an epidemic-disease area in South America, a case-control investigation was performed in Guayaquil, Ecuador, in July 1991. Residents > 5 years old who were hospitalized for treatment of acute, watery diarrhoea and two matched controls for each were interviewed regarding sources of water and food, and eating, drinking, and hygienic habits. Interviewers inspected homes of case-patients and controls to document water treatment, food-handling, and hygienic practices. Faecal specimens and shellfish were cultured for Vibrio cholerae O 1. Isolates were tested for susceptibility to a variety of antimicrobial agents. Drinking unboiled water (odds ratio [OR] = 4.0, confidence interval [CI] = 1.8-7.5), drinking a beverage from a street vendor (OR = 2.8, CI = 1.3-5.9), eating raw seafood (OR = 3.4, CI = 1.4-11.5), and eating cooked crab (OR = 5.1, CI = 1.4-19.2) were associated with illness. Always boiling drinking water at home (OR = 0.5, CI = 0.2-0.9) was protective against illness. The presence of soap in either the kitchen (OR = 0.3, CI = 0.2-0.8) or bathroom (OR = 0.4, CI = 0.2-0.9) at home was also protective. V. cholerae O 1 was recovered from a pooled sample of a bivalve mollusc and from 68% of stool samples from case-patients. Thirty-six percent of the isolates from stool specimens were resistant to multiple antimicrobial agents. Specific prevention measures may prevent transmission through these vehicles in the future. The appearance of antimicrobial resistance suggests the need for changes in current methods of prevention and treatment.

Adolescent↗
PubMed1993

Chemoarchitectonic subdivisions of the visual pulvinar in monkeys and their connectional relations with the middle temporal and rostral dorsolateral visual areas, MT and DLr.

The organization of the inferior pulvinar complex (PI) in squirrel monkeys was studied with histochemical localization of the calcium binding proteins calbindin-D28k and parvalbumin, and of cytochrome oxidase. With each of these markers, the inferior pulvinar complex can be subdivided into four distinct regions. Calbindin-D28k immunoreactivity is densely distributed in cells and neuropil within PI, except for a distinct centromedially located gap. This calbindin-poor zone, termed the medial division of the inferior pulvinar (PIM), corresponds precisely to a region that contains elevated cytochrome oxidase activity and parvalbumin immunostaining. The PIM extends slightly above and behind the classically defined limit of the inferior pulvinar, the corticotectal tract. Regions of inferior pulvinar with intense immunostaining for calbindin-D28k were the posterior division of the inferior pulvinar (PIP, medial to PIM) and the central division (PIC, lateral to PIM). A newly recognized lateral region, PIL, adjoins the lateral geniculate nucleus and stains more lightly for calbindin and parvalbumin immunoreactivity and for cytochrome oxidase. Staining patterns for calbindin, parvalbumin, and cytochrome oxidase in the pulvinar of rhesus monkeys closely resemble those shown in squirrel monkey inferior pulvinar, suggesting that a common organization exists in all primates. In order to examine cortical connection patterns of the histochemically defined compartments in the inferior pulvinar, injections of up to five neuroanatomical tracers (wheat germ agglutinin conjugated to horseradish peroxidase and fluorescent retrograde tracers) were placed in the same cerebral hemisphere. Single injection sites were in the middle temporal area (MT), and several separate injections were placed in a strip corresponding to the rostral subdivision of the dorsolateral area (DLr). Injections that involved only DLr and not MT labeled principally the PIC, and more sparsely PIP and PIL. DLr connections occupied a "shell" region dorsal to PIM that extended from PIC into the lateral and medial divisions of the pulvinar, PL and PM. Injection sites that included MT or were largely restricted to MT produced dense label in PIM and moderate label in PIC and PIL. The retinotopic organization within the inferior pulvinar was inferred from patterns of connections. Connections with cortex related most closely to central vision were found posteriorly in PIM and in adjacent portions of PIC as it wraps around the caudal pole of PIM. Cortex related to more peripheral locations in the lower visual field connected with more rostral PIM and PIC. Patterns of label within the portions of PL and PM that were immediately adjacent to PIM roughly paralleled those in PIM and PIC.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

An outbreak of diarrhea and hemolytic uremic syndrome from Escherichia coli O157:H7 in fresh-pressed apple cider.

OBJECTIVE: Escherichia coli O157:H7 causes hemorrhagic colitis and the hemolytic uremic syndrome. In the fall of 1991, an outbreak of E coli O157:H7 infections in southeastern Massachusetts provided an opportunity to identify transmission by a seemingly unlikely vehicle. DESIGN: Case-control study to determine the vehicle of infection. New England cider producers were surveyed to assess production practices and determined the survival time of E coli O157:H7 organisms in apple cider. RESULTS: Illness was significantly associated with drinking one brand of apple cider. Thirteen (72%) of 18 patients but only 16 (33%) of 49 controls reported drinking apple cider in the week before illness began (odds ratio [OR], 8.3; 95% confidence interval [CI], 1.8 to 39.7). Among those who drank cider, 12 (92%) of 13 patients compared with two (13%) of 16 controls drank cider from cider mill A (lower 95% CI, 2.9; P < .01). This mill pressed cider in a manner similar to that used by other small cider producers: apples were not washed, cider was not pasteurized, and no preservatives were added. In the laboratory, E coli O157:H7 organisms survived for 20 days in unpreserved refrigerated apple cider. Addition of sodium benzoate 0.1% reduced survival to less than 7 days. CONCLUSIONS: Fresh-pressed, unpreserved apple cider can transmit E coli O157:H7 organisms, which cause severe infections. Risk of transmission can be reduced by washing and brushing apples before pressing, and preserving cider with sodium benzoate. Consumers can reduce their risk by only drinking cider made from apples that have been washed and brushed.

Adolescent↗
PubMed1993

Wound botulism in a patient with a tooth abscess: case report and review.

We describe a case of wound botulism associated with a tooth abscess in a 5-year-old boy. We reviewed the literature and reports to the Centers for Disease Control and Prevention (Atlanta) of laboratory-confirmed cases of wound botulism. From 1943 through 1990, 47 cases were reported. Type A botulinus toxin was identified in 32 cases, type B in 13, types A and B in 1, and an unknown type in 1. Botulism was associated with wounds from trauma, use of injectable drugs, and surgery. Sinusitis after use of intranasal cocaine has also been associated with botulism. Treatment for wound botulism includes prompt debridement of the wound for eliminating anaerobic conditions, intensive care, and treatment with antitoxin.

Botulinum Toxins↗
PubMed1993

A massive outbreak of type E botulism associated with traditional salted fish in Cairo.

In April 1991, 91 hospitalized patients in Cairo were reported to the Egyptian Ministry of Health with botulism intoxication. To define the spectrum of illness and identify a food vehicle, 45 patients were interviewed and a case-control investigation was conducted among families of 5 hospitalized patients. Clinical specimens and specimens of implicated food were tested for toxin and cultured for Clostridium botulinum. Hospitalized patients had symptoms consistent with botulism; 18 (20%) of 91 reported patients died. Illness was associated with eating faseikh (uneviscerated, salted mullet fish; lower 95% confidence limit of odds ratio = 6.6, P < .001). All 5 case-families purchased faseikh from one shop. Very high levels of type E botulinal toxin were detected in faseikh reported to be purchased from the implicated shop; C. botulinum type E was isolated from cultures of clinical specimens and from the faseikh. This is the first documented outbreak of botulism in Egypt and the largest type E outbreak ever reported.

Adolescent↗
PubMed1992

Synaptic connections of central carotid sinus afferents in the nucleus of the tractus solitarius of the rat. I. An electron microscopic study.

A transganglionic transport technique was used to study the synaptic connections of the central carotid sinus afferents in the nucleus of the tractus solitarius of the rat by electron microscopy. The caudal part of the nucleus was profusely innervated. Labelled fibres extended to the contralateral nucleus, and to the ipsilateral dorsal motor nucleus of the vagus nerve, nucleus ambiguus, spinal nucleus of the trigeminal nerve and the area postrema. The labelled terminals were densely packed with clear, predominantly spherical vesicles about 50 nm in diameter and a few often swollen mitochondria. The terminals synapsed on dendrites of various calibres, spindle- or pear-shaped somal profiles with short axes lesser than 8 microns, and axon terminals. In axo-axonal synapses, most labelled terminals appeared to be presynaptic. Frequently, profiles of labelled terminals were in direct apposition with one another. The latter may represent the morphological substrate of the interaction between baro- and chemoreceptor inputs in the nucleus of the tractus solitarius and warrants further study. The present results indicate that in addition to direct inputs, the carotid sinus afferents are able to influence second-order neurons in the nucleus of the tractus solitarius indirectly through presynaptic modulation.

Afferent Pathways↗
PubMed1992

Modulation of chloride secretion in the rat colon by intracellular bicarbonate.

Extracellular HCO3- stimulates colonic net Cl- absorption in part by inhibiting basal Cl- secretion. This inhibition was investigated by measuring serosal-to-mucosal Cl- flux across short-circuited colonic segments from Sprague-Dawley rats. Mucosal intracellular pH and bicarbonate were estimated using the pH-sensitive dye BCECF. When extracellular [HCO3-] ([HCO3-]e) was increased from 0 to 39 mmol/L at PCO2 33 mm Hg, mucosal intracellular [HCO3-] ([HCO3-]i) increased to 25.3 mmol/L and serosal-to-mucosal Cl- flux decreased from 13.0 to 7.1 microEq.cm-2.h-1. When PCO2 was increased to 72 mm Hg at [HCO3-]e 39 mmol/L, [HCO3-]i increased to 29.8 mmol/L and serosal-to-mucosal Cl- flux decreased to 5.9 microEq.cm-2.h-1. In Ringer's solution containing 21 mmol/L HCO3- and 20 mmol/L Cl- (but not 100 mmol/L Cl-), increasing PCO2 from 21 to 70 mm Hg increased [HCO3-]i to 22.6 mmol/L and decreased serosal-to-mucosal Cl- flux from 3.0 to 1.7 microEq.cm-2.h-1. Overall, serosal-to-mucosal Cl- flux was inversely related to [HCO3-]i on either side of an [HCO3-]i plateau of 9-18 mmol/L at which flux was stable. These data suggest that [HCO3-]i is an important modulator of basal Cl- secretion in rat distal colon.

Animals↗
PubMed1991

The parabigeminogeniculate projection: connectional studies in eight mammals.

Anterograde and retrograde tracing methods have been used to analyze the origin and distribution of parabigeminogeniculate axons in the gray squirrel, the gopher, the rat, the opossum, the cat, the greater bushbaby, the squirrel monkey and the macaque monkey. Our findings reveal that parabigeminogeniculate axons most heavily innervate regions of the lateral geniculate that are also targeted by axons arising from the superior colliculus (tectogeniculate). These geniculate layers and zones of parabigeminal and tectal overlap contain small cells, and in several species are associated with the small W cell retino-geniculocortical pathway. In addition to the dense input to small-celled layers and zones, parabigeminal axons in several species also innervate regions of the lateral geniculate nucleus that are relatively free of tectogeniculate axons and that are associated with the medium (X) and large (Y) cell streams. Finally, our data reveal that the laterality of parabigeminogeniculate pathways varies across mammals, being primarily crossed in the gray squirrel, the gopher, the rat, and the opossum, bilateral in the cat, and primarily ipsilateral in the three primates.

Animals↗