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Biomedical subjects

J N Sheagren

Publications and source records attributed to J N Sheagren.

At least 19 recordsLinked to original sources
PubMed1991

Corticosteroids for the treatment of septic shock.

Despite the substantial amount of data supporting the use of glucocorticoids in experimental models in septic shock, patients with severe sepsis and signs of deteriorating hemodynamic status or organ function do not benefit from glucocorticoid administration as given under the conditions of two well-done prospective, controlled trials. In fact, some glucocorticoid-treated patient subgroups showed increased mortality. Thus, the conclusion must be drawn that, despite potential theoretical and experimental value, glucocorticoids should not be used in the septic patient.

Animals↗
PubMed1990

Impact of encephalopathy on mortality in the sepsis syndrome. The Veterans Administration Systemic Sepsis Cooperative Study Group.

Sepsis, an important cause of hospital mortality, continues to be a diagnostic and therapeutic challenge. To define more clearly the impact of encephalopathy on the course of sepsis, the various clinical signs of sepsis, blood culture results, and mortality rates were examined in relation to mental status in septic patients. Patients were classified as having an acutely altered mental status due to sepsis (AAMS), preexisting altered mental status (PAMS), or normal mental status (NMS). Twenty-three (307/1333) percent of the study patients had an acutely altered sensorium secondary to sepsis. Patients with AAMS had a higher mortality (49%) than patients with PAMS (41%) or patients with NMS (26%) (p less than .000001). Multivariate analysis disclosed that altered mental status, hypothermia, hypotension, thrombocytopenia, and the absence of shaking chills were independent predictors of increased mortality in the sepsis syndrome. Patients with Gram-negative bacteremia (28%) were as likely to have AAMS as patients with Gram-positive bacteremia (25%) or patients with negative blood cultures (23%). In summary, alterations in mental status are common in septic patients, and are associated with significantly higher mortality.

Bacterial Infections↗
PubMed1989

Mechanism-oriented therapy for multiple systems organ failure.

Damage caused by systemic sepsis is only in part caused by the viable microbe and therefore treatable by antibiotics. Most damage is produced by host defenses. The rationale for anti-inflammatory therapy in severely septic patients is based on these concepts. A variety of anti-inflammatory agents are being studied that might help "tide the patient through" the initial phases of the septic event until antimicrobial therapy has had a chance to work. Antibiotics certainly help minimize the suppurative complications of bacteremia/septicemia. The initial approach to the septic patient should be rapid but thorough, permitting data to be gathered that will permit decisions ultimately to be made as to whether or not sepsis was actually present and what appropriate therapeutic agents are best for longer term treatment. The septic patient will continue to provide a challenge to the clinician. The better one understands the mechanisms involved in the pathophysiology of the development of severe sepsis, septic shock, and the syndrome of MSOF, the better will become the clinical management of such patients. Also, development of additional such insights will certainly permit important new therapeutic modalities to evolve.

Anti-Bacterial Agents↗
PubMed1988

Relationship of health-related variables to levels of anti-polyribosylribitol phosphate antibodies in adults.

To identify adults who may be at risk for Haemophilus influenzae type b disease by virtue of low levels of antibody against the H. influenzae b capsule and who may thus benefit from receiving H. influenzae b vaccine, we correlated serum anticapsular antibody levels of 388 adult patients with 26 health-related variables, including 3 personal characteristics, 10 laboratory values, 4 drug use categories, and 8 disease categories. Steroid use was consistently associated with low levels of anticapsular antibody; associations were also found between low antibody levels and both non-Caucasian race and increasing age. However, less than 4% of the antibody variability could be attributed to these factors, and they were not predictive of low antibody levels. Thus, although H. influenzae b infections are seen in adults with predisposing medical conditions, on the basis of the present findings, use of the H. influenzae b vaccine in adults cannot be recommended.

Adult↗
PubMed1986

Hemophilus influenzae type B cellulitis in adults.

Cellulitis due to Hemophilus influenzae type B is a rare but treatable event in adults. Herein is described a 67-year-old woman with anterior neck cellulitis caused by H. influenzae type B, documented by positive blood culture results. Six additional cases reported in the literature are reviewed. The following clinical syndrome emerges: the patient is usually older than 50 years of age, and pharyngitis develops first, followed by the onset of high fever and rapidly progressive anterior neck swelling, tenderness, and erythema associated with dysphagia. Because the causative organism may be resistant to ampicillin, the early use of chloramphenicol is recommended along with a beta-lactamase-resistant penicillin or cephalosporin (to cover other potential pathogens), or an appropriate third-generation cephalosporin that would also adequately cover all possible pathogens.

Aged↗
PubMed1986

The role of endorphins and vasopressin in canine endotoxin shock.

Chemical antagonists were used to assess the role of beta-endorphin and arginine-vasopressin (AVP) in canine endotoxin shock. Fifteen awake dogs were given Escherichia coli endotoxin IV. Within 5 min, CO decreased to 28%, LV dP/dt to 46%, and MAP to 52% baseline. Fifteen minutes after endotoxin, five dogs each received naloxone, AVP antagonist, or no treatment. Control (untreated) animals exhibited persistent cardiovascular depression, with CO 49%, LV dP/dt 69%, and MAP 91% of baseline after 45 min. Naloxone improved CO to 69%, LV dP/dt to 94%, and MAP to 91% by 30 min after treatment. AVP blockade improved CO to 105%, LV dP/dt to 107%, and MAP to 95% of baseline by 30 min after treatment, and caused significant tachycardia. Plasma cortisol and AVP increased markedly in all groups after endotoxin administration. AVP antagonist treatment increased mean survival from 1.4 to 4 days. These data suggest that abnormally elevated AVP contributes to cardiovascular depression in canine endotoxin shock and that AVP blockade is therapeutic in the animal model studied.

Animals↗
PubMed1986

Gnotobiotic models for study of the microbial ecology of Clostridium difficile and Escherichia coli.

Hamster flora introduced into germfree mice reduced the cecum to conventional size, suppressed populations of Escherichia coli and Clostridium difficile to the same degree that mouse flora did, and corrected the hypocellularity that is characteristic of the small bowel of germfree mice. A highly toxigenic strain of C. difficile readily induced cecitis in germfree and antibiotic-treated conventional mice, and histological examination frequently revealed pseudomembranes. Toxins A and B were both detected in ceca of animals with colitis. Gnotobiotic mice provide a model in which to study the role of the indigenous microflora in protecting against antibiotic-associated colitis.

Animals↗
PubMed1985

Staphylococcal infections of the skin and skin structures.

A review of the pathogenesis, clinical manifestations, diagnosis, and therapy of staphylococcal skin and skin structure infections begins with discussion of the staphylococcal carrier state. Patients carrying Staphylococcus aureus are particularly vulnerable to infection if their skin is broken by wounds or placement of intravenous lines or catheters. S. aureus begins the process of infection by binding tightly to fibronectin-coated surfaces and endothelial cells; bacterial invasion, however, depends on the innate pathogenicity of the bacterial strain and on the status of the host's defenses. The carrier state may be manifested by recurrent infections in the skin and skin structures. Infection may be spontaneous, associated with skin trauma and/or presence of a foreign body, or related to the presence of bacteria. For diagnosis, appropriate samples of purulent materials are needed for Gram stain and culture. Drainage is absolutely essential. Most staphylococci are now penicillinase-producing. Initial coverage with a cell-wall-active agent combined with an aminoglycoside is usually highly effective. If a methicillin-resistant organism is suspected, vancomycin should be used. Treatment of the carrier state may eliminate recurrent episodes of staphylococcal skin infection. Meticulous infection-control procedures are extremely important in the prevention of staphylococcal infection of the skin and skin structures.

Carrier State↗
PubMed1985

Epidemiology and clinical significance of blood cultures positive for coagulase-negative staphylococcus.

Coagulase-negative staphylococci are frequently isolated from blood cultures. As these organisms may occasionally cause serious disease, differentiating bacteremia from contamination is very important but often difficult. Over a 26-month period, of 29,542 blood cultures processed at the University of Michigan Medical Center, 2,875 (9.7%) were positive, and of those, 694 (from 527 patients) grew coagulase-negative staphylococci. Isolates from the 439 patients with only one blood culture positive for coagulase-negative staphylococci and those from the 18 patients with two positive cultures 10 days or more apart were deemed contaminants. Review of the records of the remaining 70 patients with multiple isolates indicated that 33 had had an episode of true bacteremia, 29 (87.9%) of which were associated with intravascular catheters or prosthetic valves. Overall, 85% of all coagulase-negative staphylococci isolated during the study period were judged to be contaminants. Seventy-one percent of the blood cultures drawn during the episodes of bacteremia were positive for coagulase-negative staphylococci as opposed to only 34% in the patients with contaminated cultures (p less than 0.01). Moreover, coagulase-negative staphylococci grew in both aerobic and anaerobic bottles in 85% of blood culture sets drawn during episodes of bacteremia, but in only 30% of the cultures thought to be contaminated (p less than 0.001). Growth of coagulase-negative staphylococci in less than 48 hours was also significantly associated with bacteremia (p less than 0.01). Antibiotic sensitivity patterns were not useful in differentiating bacteremia from contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Population dynamics of ingested Clostridium difficile in the gastrointestinal tract of the Syrian hamster.

The population dynamics of Clostridium difficile in the hamster gastrointestinal tract were studied after intragastric inoculation with organisms and a 51Cr tracer. Seventy-eight percent of spores germinated within the small intestine within 1 hr. Germinated spores and vegetative cells both showed two phases of elimination from the hamster cecum--an initial phase of rapid death that was not affected by antibiotic treatment followed by a phase of complete inhibition of multiplication. The latter phase of inhibition was not seen in antibiotic-treated animals and was thus attributable to the indigenous flora. The 51Cr tracer mixed well with cecal contents and was eliminated exponentially with a dilution rate constant ranging from -0.46/hr to -0.31/hr in normal hamsters. The hamster cecum was therefore dynamically analogous to a continuous flow system, a finding supporting the concept that anaerobic continuous flow cultures are useful in vitro models of the cecal ecosystem.

Animals↗