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Biomedical subjects

J Silva

Publications and source records attributed to J Silva.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

Oxygen saturation and heart rate in healthy school children and adolescents living at high altitude.

This study was conducted to establish reference values for percent oxygen saturation of hemoglobin (SaO2, %) and heart rate (HR, bpm) in children living at high altitude (4,100 m) and to relate possible differences in the variables with ethnic origin. Healthy children from a mine-located school (Tintaya, n = 417), a nearby school (Marquiri, n = 474), and a rural Andean community (Nuñoa, n = 373) were investigated. The samples included different ethnic combinations, with the Nuñoa children having a predominant Quechua ancestry. Mean SaO2 for all ages was substantially lower in all high altitude children compared to values considered normal for sea level. Among the three samples, SaO2 was higher (91.3 +/- 2.7) and HR was lower (84.8 +/- 13.6) in Nuñoa than in Tintaya (SaO2, 89.8 +/- 2.5; HR, 91.7 +/- 14.9) and Marquiri (SaO2, 89.6 +/- 3.1; HR, 88.5 +/- 12.9) (P < 0.05). There was no sex difference and only a weak age-dependent trend for SaO2. Values considered abnormal at sea level were observed in all healthy high-altitude children. Higher SaO2 and lower HR in Nuñoa children may suggest a better degree of acclimatization to altitude.

Acclimatization↗
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Funguria in cancer patients: analysis of risk factors, clinical presentation and outcome in 50 patients.

Fifty cancer patients with funguria of > 10(5) CFU/ml, dysuria and leukocyturia were retrospectively analyzed for etiology, risk factors and outcome. In 72% of cases Candida albicans and in 28% non-albicans Candida spp. (Candida krusei, Candida tropicalis) and non-Candida spp. yeasts (Blastoschizomyces capitatus) were isolated. Torulopsis glabrata was not found among these patients. The most frequent risk factors were: antibiotic therapy with more than one antibiotic agent (96%), concomitant fungal infection in other localizations than the urinary tract (36%), colonization with the same species (48%), catheterization with urinary catheter or nephrostomy (46%), prophylaxis with quinolones (50%) and previous therapy with corticosteroids (72%). Structural or anatomic malformations of the urinary tract (26%), neutropenia (28%), antifungal prophylaxis with azoles (22%), and diabetes mellitus (12%) were less frequently seen. Thirty of 36 patients treated with systemic antifungals were cured and six were not.

Blastomycosis↗
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Pedestrian accidents: adult and pediatric injuries.

An epidemologic review of 217 pedestrian injuries treated at a level one trauma center during a one-year period is presented. Injuries that occurred in pediatric age group patients were reviewed separately from adults. In both categories approximately 60% were admitted to the hospital. Hospital length of stay and severity of injuries was found to be much worse in adults. Seven percent of adults and 3% of children died after arrival at the hospital. The most common areas of injury in both groups were the head and the distal extremities. Nearly 25% of adults sustained tibia-fibular fractures. This study shows that the incidence of critical injuries in pedestrians is high, and adults sustain more severe injuries than children. We clarify types of injuries commonly seen in pedestrian trauma.

Accidents, Traffic↗
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Hyperglycemia induced by acute central fluoxetine administration: role of the central CRH system and 5-HT3 receptors.

Brain serotonin and CRH systems participate in the control of blood glucose levels. We have previously demonstrated that the pharmacological stimulation of central 5-HT3 receptors, the target for several therapeutic agents used as antiemetics in the course of chemotherapy, induces hyperglycemia. The aim of the present study was to investigate the participation of the brain CRH component and 5-HT3 receptors in basal blood glucose levels as well as in the hyperglycemia induced by third ventricle injections of fluoxetine, a serotonin reuptake inhibitor with a broad range of clinical use. In this study, we used fasted adult Wistar male rats (220 +/- 20 g) whose third ventricles were cannulated 7 days prior to the experiments. Acute third ventricle injections of fluoxetine caused a significant increase in plasma glucose levels throughout the experiment. Pretreatment with alpha-helical CRH, a selective CRH antagonist, significantly blunted fluoxetine-induced hyperglycemia. Also, pretreatment with two distinct selective 5-HT3 receptor antagonists (LY-278,584 and ondansetron) significantly impaired the rise in plasma glucose levels observed in fluoxetine-treated animals pretreated with isotonic saline solution. None of these antagonists was able to modify blood glucose levels when injected alone into the third ventricle. Animals receiving third ventricle injections of fluoxetine, in spite of being hyperglycemic, presented plasma insulin levels similar to those displayed by normoglycemic, saline-treated controls. It is suggested that the acute increase in brain serotonergic activity caused by third ventricle injections of fluoxetine induces a hyperglycemic response that requires the functional integrity of the brain CRH system and 5-HT3 receptors. Also, it is proposed that the absence of a compensatory increase in plasma insulin levels may contribute to the generation of a hyperglycemic response after central fluoxetine administration.

Animals↗
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Antibiotic-associated colitis: effects of antibiotics on Clostridium difficile and the disease in hamsters.

Fifteen isolates of Clostridium difficile from hamsters and human patients were inhibited or killed by low concentrations of metronidazole, vancomycin, penicillin, and ampicillin; the isolates were often reesistant to tetracycline, cephalosporins, trimethoprim-sulfamethoxazole, clindamycin, erythromycin, and aminoglycosides. Antibiotics to which C. difficile was susceptible were able to prevent or postpone the colitis caused by clindamycin in hamsters. Colitis could be produced by treatment of hamsters with any one of these antibiotics. Production of colitis not only involved selection of resistant variants, but in some instances seemed to result from the acquisition of organisms after treatment, their persistence despite treatment, or from subinhibitory cecal concentrations of antibiotic (explainable by either pharmacologic factors or enzymatic inactivation). As in humans, no organisms other than C. difficile have been implicated conclusively as etiologic agents of colitis in hamsters. Our results suggest it may be wise to use isolation precautions for patients with colitis caused by C. difficile.

Animals↗
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Endocarditis due to Streptococcus faecalis with high-level resistance to gentamicin.

Recently, reports of Streptococcus faecalis with resistance to high levels of gentamicin have appeared in the literature, although there have been no previous reports of endocarditis due to such organisms. In this article, two cases of endocarditis--both due to Streptococcus faecalis with high-level gentamicin resistance and both presenting in an atypical manner--are described. The data suggest that a high level of suspicion regarding a diagnosis of endocarditis must be maintained in such cases and that, once a case is diagnosed, careful evaluation in the microbiology laboratory is helpful in determining the optimal antimicrobial regimen.

Aged↗
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Fatal varicella in an adult: case report and review of the gastrointestinal complications of chickenpox.

An unusual and fatal case of primary varicella in an adult is presented. Involvement of the small intestine first manifested as abdominal pain and later progressed to gastrointestinal bleeding with subsequent dissemination of the infection. Although it has previously been speculated that gastrointestinal bleeding can result from infection with the varicella-zoster virus, the data from this case include histologic and cultural evidence that supports the clinical observations. The literature has been reviewed, and the management of this patient has been critically evaluated.

Abdominal Pain↗
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Use of the polymerase chain reaction for the specific and direct detection of Clostridium difficile in human feces.

The polymerase chain reaction was used for the detection of Clostridium difficile, the etiologic agent of antibiotic-associated colitis. An upstream primer identical to a coding region (segment I) of the C. difficile 16S rRNA gene and a downstream primer complementary to a highly conserved region of eubacterial 16S rRNA served to amplify a targeted 270-base-pair fragment of genomic DNA. This technique allowed the detection of as few as 10 C. difficile organisms among 10(6) Escherichia coli bacteria. This level of sensitivity represents a 100-fold increase over that of conventional anaerobic culture. C. difficile was detected in DNA extracted directly from the stools of 23 patients with antibiotic-associated colitis and from those of four patients with diarrhea whose stools had been negative for C. difficile when assessed in a cytotoxicity assay. No amplification products were found in the stools of asymptomatic patients. When detected in stools of symptomatic patients, amplification products of C. difficile were confirmed by Southern blotting with a nonradioactive, horseradish peroxidase-catalyzed, chemiluminescent probing system in which biotin-labeled oligonucleotides were used. This system discriminates between C. difficile and similar organisms, such as Clostridium sordellii and Clostridium bifermentans. The combination of the polymerase chain reaction with enzyme-linked probing results in a faster and more sensitive assay for C. difficile than standard culture.

Base Sequence↗
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Rifampin and pseudomembranous colitis.

Isolates of toxigenic Clostridium difficile, the most frequent cause of antibiotic-associated pseudomembranous colitis, are almost always highly susceptible to rifampin. However, resistant isolates exist and have been associated with colitis in both hamsters and humans given rifampin. Rifampin is rarely implicated in the disease in humans; only six cases have been documented, all in elderly patients receiving treatment for tuberculosis. At least three of these patients had liver disease, and all six had also received one or more other antimicrobial agents. The only isolate of C. difficile from these patients that was studied was resistant to rifampin. The colitis was usually mild and responsive to discontinuation of treatment with rifampin or to oral treatment with vancomycin.

Aged↗
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Inciting and etiologic agents of colitis.

Since 1979, 3,115 stool samples were tested for detection of Clostridium difficile and its cytotoxin; these were obtained from patients who had drug-related diarrhea. Presumed or proven colitis due to C. difficile was diagnosed in 130 patients. Drugs implicated most commonly as causing or associated with the onset of enterocolitis due to C. difficile were ampicillin (38 episodes), cephalosporins (71), clindamycin (36), and the aminoglycosides (45). The hamster model of colitis was employed to explore the role of other inducing agents. Altering the usual diet of hamsters to one with a higher protein content decreased the time to death due to C. difficile cecitis following the administration of cefazolin (10 mg). Several cathartics also were studied for their effect on the lethality of antibiotic-induced cecitis. Daily administrations of castor oil (0.5 ml per day) and vegetable oil (1.0 ml per day) improved survival against lethal doses of clindamycin. Milk of magnesia or mineral oil provided no protection. Four patients with C. difficile colitis induced by therapy with cytotoxic drugs also were identified. Methotrexate induced cecitis when administered orally and daily to hamsters, and C. difficile and its cytotoxin were identified in the hamsters' stools. Death due to methotrexate-induced cecitis was prevented by daily administration of folinic acid or vancomycin. These data demonstrate that a variety of antibiotics, antineoplastic agents, cathartics, and diet changes can induce C. difficile colitis in humans and hamsters.

Animals↗
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Disseminated histoplasmosis, invasive pulmonary aspergillosis, and other opportunistic infections in a homosexual patient with acquired immune deficiency syndrome.

A homosexual man with the acquired immune deficiency syndrome had an unusually wide array of opportunistic infections. Despite antibiotic treatment over a period of two and a half years, the patient died. Perianal herpetic ulcers, oral candidiasis, cytomegalovirus infection, and disseminated infections with both Histoplasma capsulatum and Mycobacterium avium-intracellulare were diagnosed during illness. An autopsy revealed invasive pulmonary aspergillosis and a cerebellar lesion caused by cytomegalovirus. The latter was probably responsible for the patient's gait disturbance.

Acquired Immunodeficiency Syndrome↗
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Total parenteral nutrition catheter sepsis: impact of the team approach.

For a period of 32 months from the inception of the Parenteral and Enteral Nutrition (PEN) Team at the University of Michigan, the infection rate (IR) related to central venous catheters (CVCs) for total parenteral nutrition (TPN) was prospectively evaluated. Six hundred twenty-two catheters were placed in 377 patients for a total of 9,200 patient days. The length of CVC stay ranged from 2 to 108 days with a mean of 14.5. CVC longevity was longer on units where certification of nurses by the PEN team was mandatory (mean 20.4 days, IR 3.5%) vs comparable units which utilized informal instruction (mean 14.4 days, IR 3.5%). Twenty-two catheters led to patient sepsis for a rate of 3.5%, or 2.39 CVC-related infections per 1000 patient days. The preteam infection rate was 24.0%, as determined by a 6-month prospective study. Infection rates for CVCs used for TPN only and those used for parenteral nutrition (PN) plus blood products, antibiotics, and CVP measurements were identical, 3.5%. The team approach can effectively increase PN catheter longevity and reduce infection rates. Conservative cost accounting of best and worst case scenarios determined a range of $3,700 to $8,900 per episode of catheter sepsis.

Catheters, Indwelling↗
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Aerobic isolates in hemovac lines.

Positive aerobic isolates from hemovac lines were found in 41 of 68 patients (60%) who had major head and neck procedures requiring the hemovac drainage system during the postoperative period. When studied up to six days of placement, the number and the type of organisms in a hemovac system generally remained the same. A clue to impending infection was the isolation of two or more different genera from the hemovac system. Isolates from hemovac lines can frequently indicate the cause of the complication. Possible pathogens in postoperative head and neck infections include gram-positive bacteria, gram-negative bacteria, and fungi.

Adult↗
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EEG coherences in patients with brain lesions.

EEG coherence between all pairwise combinations of the 10/20 system was studied in two groups: control subjects and patients with space-occupying brain lesions. Coherence was separately computed for the delta, theta, alpha and beta bands. Comparisons between both groups showed highly significant differences in all bands. In the patients with lower coherence values, these differences were mainly in the alpha band. When intra-hemispheric coherences between controls and patients with left hemispheric lesions were compared, significant differences were observed only in the left hemisphere. Comparisons between controls and patients with lesions in the right hemisphere also showed significant differences only in the injured hemisphere. In patients, paired t tests between the values of the intra-hemispheric coherence in the left hemisphere and the corresponding values in the right hemisphere demonstrated that lower coherences were confined to the damaged hemisphere. Our conclusion is that in the presence of lesions disrupting cortex and adjacent white matter the coherence between this area and the remaining cortical areas is lower than normal due to impairment of the fibers that connect the damaged area with the rest of the brain.

Adolescent↗
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Birth after electroejaculation coupled to intracytoplasmic sperm injection in a gun-shot spinal cord-injured man.

We describe the case of a man who, after a gun-shot wound, has become paraplegic. As a consequence of his spinal cord injury he developed infertility due to incomplete erection and anejaculation. After several unsuccessful penile vibratory stimulation attempts, it was possible to achieve ejaculation by means of transrectal electrostimulation. However, the total sperm motility count, the percentage of normal sperm morphology, and the vitality and hypo-osmotic swelling test scores were rather low, and in particular viability was strikingly decreased during sperm preparation. These parameters further decreased following electroejaculate, forcing us to use intracytoplasmic sperm injection instead of conventional in vitro fertilization for the treatment cycle. A normal pregnancy was achieved which resulted in birth of a healthy girl on 1st January 1997.

Adult↗
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Bacteroides fragilis enterotoxin gene sequences in patients with inflammatory bowel disease.

We identified enterotoxigenic Bacteroides fragilis in stool specimens of patients with inflammatory bowel disease and other gastrointestinal disorders. The organism was detected in 11 (13.2%) of 83 patients with inflammatory bowel disease. Of 57 patients with active disease, 19.3% were toxin positive; none of those with inactive disease had specimens positive for enterotoxigenic Bacteroides fragilis gene sequences.

Adolescent↗
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Anaerobic infections.

The treatment of anaerobic infection will be improved by: (1) having a high index of suspicion of anaerobic bacteria in all infections, (2) recognition of clinical signs characteristic of some of these infections, and (3) institution of antibiotics that are likely to be appropriate before the culture results become available 4 to 7 days later.

Anaerobiosis↗