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Biomedical subjects

R Floyd

Publications and source records attributed to R Floyd.

At least 19 recordsLinked to original sources
PubMed1999

Hepatocellular carcinoma in pregnancy. A case report.

BACKGROUND: Hepatocellular carcinoma presenting in pregnancy is very rare, and experience treating this condition is limited. Past reports have emphasized the need for pregnancy termination as part of treatment. CASE: A young, otherwise healthy woman was diagnosed with hepatocellular carcinoma in the second trimester. Her only risk factor was a six-year history of oral contraceptive use. She opted to maintain the pregnancy and was treated with surgical resection in the form of a right hepatectomy. Both she and her child were alive and well 24 months following surgery. CONCLUSION: Hepatocellular carcinoma in pregnancy can be successfully treated by surgical resection without adjuvant therapy; pregnancy termination is not mandatory.

Adult↗
PubMed1998

Effect of sleep deprivation on serum influenza-specific IgG.

Intra-pulmonary protection against influenza virus in immune mice, largely dependent upon serum lgG, is reported to be suppressed by 7 hours of sleep deprivation following viral challenge. This implies that sleep deprivation may accelerate the catabolism of influenza-specific antibodies. To determine the effects of sleep deprivation on the catabolism of serum antibodies, BALB/c mice were passively immunized intravenously with lgG anti-influenza monoclonalantibodies and catabolism kinetics monitored for 6 days. Mice were then sleep-deprived for either 9 hours (one episode) or for 9 hours followed by 6 hours on the consecutive day (two episodes) and the serum titer of influenza-specific monoclonal antibodies monitored for an additional 8 days via ELISA. One episode of sleep-deprivation had only minor effects on lgG catabolism; however, two episodes of sleep-deprivation caused significant changes in the kinetics of lgG catabolism, resulting in elevated lgG levels (p = 0.02) for 2 days post-sleep deprivation. Elevation of serum influenza-specific lgG (p = 0.005) was also seen in actively immune mice following two episodes of sleep-deprivation. Serum chemistries ruled out dehydration as a cause of the increased antibody levels; however, some anomalies were noted: total protein and albumin were elevated, although not significantly, and P and Ca were decreased. Thus, our data do not support the hypothesis that sleep-deprivation lowers existing serum antibody titers by accelerating antibody catabolism.

Animals↗
PubMed1996

Effects of systemic GHRH on sleep in intact and hypophysectomized rats.

The role of pituitary growth hormone (GH) in the mediation of enhanced sleep elicited by GH-releasing hormone (GHRH) was studied in the rat. Intact and hypophysectomized (HYPOX) rats received systemic injections of GHRH or physiological saline. GHRH (0.5, 5.0, or 50 micrograms/kg in the intact rats and 0.5 or 50 micrograms/kg in HYPOX rats) was injected 6 h after light onset (P.M. injection) or just before light onset (A.M. injection, 0.5 microgram/kg in both A.M. groups). Sleep-wake activity and brain cortical temperature were recorded for 23 h (12 h light + 11 h dark). A.M. injection of GHRH did not alter sleep in normal or HYPOX rats. Each dose of P.M. GHRH increased rapid-eye-movement sleep (REMS) during 6 h postinjection in the intact rats. Hypophysectomy abolished the REMS-promoting activity of GHRH. P.M. injection of 0.5 microgram/kg GHRH increased non-REM sleep (NREMS) and enhanced electroencephalogram slow-wave activity during NREMS in both the intact and the HYPOX rats. The NREMS-promoting activity disappeared when the dose of GHRH was increased in the intact rats, whereas a tendency to enhanced NREMS was still observed after 50 micrograms/kg GHRH in the HYPOX rats. GHRH stimulated GH secretion dose dependently in the intact rats. A.M. injection of 0.5 microgram/kg GHRH tended to be less effective in stimulating GH release than the same dose administered P.M. The results confirm the time-of-day variations in the GHRH effects on sleep previously reported in human subjects. It is likely that pituitary GH is involved in the mediation of the REMS-promoting activity of GHRH but not in the NREMS-promoting activity of GHRH. Nevertheless, the results do not exclude the possibility that GH may modulate NREMS.

Animals↗
PubMed1995

Cytokines in sleep regulation.

The central thesis of this essay is that the cytokine network in brain is a key element in the humoral regulation of sleep responses to infection and in the physiological regulation of sleep. We hypothesize that many cytokines, their cellular receptors, soluble receptors, and endogenous antagonists are involved in physiological sleep regulation. The expressions of some cytokines are greatly amplified by microbial challenge. This excess cytokine production during infection induces sleep responses. The excessive sleep and wakefulness that occur at different times during the course of the infectious process results from dynamic changes in various cytokines that occur during the host's response to infectious challenge. Removal of any one somnogenic cytokine inhibits normal sleep, alters the cytokine network by changing the cytokine mix, but does not completely disrupt sleep due to the redundant nature of the cytokine network. The cytokine network operates in a paracrine/autocrine fashion and is responsive to neuronal use. Finally, cytokines elicit their somnogenic actions via endocrine and neurotransmitter systems as well as having direct effects neurons and glia. Evidence in support of these postulates is reviewed in this essay.

Acute-Phase Reaction↗
PubMed1989

Recovery of human immunodeficiency virus and detection of p24 antigen in bronchoalveolar lavage fluid from adult patients with AIDS.

Published reports indicate that HIV is recovered from BAL fluid of patients with AIDS who have LIP but not with other AIDS-related pulmonary disease. Our experience has been different. Ten BAL specimens from nine patients with AIDS were cultured directly in peripheral blood mononuclear cells, and all ten cultures were positive for HIV as indicated by examination of the culture supernatant by reverse transcriptase assay and enzyme immunoassay for HIV antigen. Five of the specimens were also positive for Pneumocystis carinii, and other pulmonary diagnoses included histoplasmosis, lymphoma, Kaposi's sarcoma, and aspiration pneumonia. Five additional BAL specimens were cultured after freezing at -70 degrees C, but only two were culture-positive for HIV (p = 0.022; FET). This study indicates that HIV can be recovered from the BAL fluid in most patients with AIDS, unrelated to the type of pulmonary disease. In contrast to cultures, HIV antigen was detected in the BAL fluid of only one patient, and that patient had LIP with noncaseating granulomas. Therefore, HIV culture is not useful in the diagnosis of LIP, but HIV antigen detection should be studied further. All BAL fluids should be considered potentially infectious.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Gentamicin-resistance plasmids in an intensive care unit.

To better understand the role of plasmids and their importance in the endemic antibiotic resistance of Enterobacteriaceae, we began a prospective study of our combined medical intensive care/coronary care unit. An initial culture survey of the patients, ward staff, and environment was followed by a prospective sampling of 139 consecutive new admissions at the time of admission to the unit, and at regular intervals thereafter for the remainder of their stay. All cultures were planted on agar-containing gentamicin. Of the 147 patients studied, 12 (8.2%) were colonized with 20 strains of gentamicin-resistant gram-negative bacilli (GRGNB) at 29 sites. An additional four GRGNB were isolated from the environment. Of the 24 GRGNB strains, 7 (29%) Enterobacteriaceae carried plasmids shown to carry the gentamicin-resistance determinant. Plasmids were further characterized by restriction endonuclease digestion profiles of plasmid DNA purified from E. coli C600 transconjugants or transformants. A 93 kb plasmid introduced to the unit by a Serratia liquefaciens colonizing a patient transferred from another area in the hospital was identical to 93 kb plasmids carried by a C. amalonaticus and an E. aerogenes subsequently colonizing another patient on the unit. A 60 kb plasmid, first isolated from a S. marcescens colonizing a sink drain was later isolated from an E. cloacae colonizing a patient. Our results indicate that spread of specific R-plasmids may be one mechanism for dissemination of antibiotic resistance on our MICU/CCU.

Drug Resistance, Microbial↗
PubMed1986

Prevalence of colonization with antibiotic resistant gram-negative bacilli in a nursing home care unit: the importance of cross-colonization as documented by plasmid analysis.

A prevalence study was carried out on a 100-bed Veterans Administration nursing home care unit to determine the extent of colonization with gentamicin-resistant gram-negative bacilli (GRGNB). Hand cultures of 12 employees and 17 environmental cultures were negative. Twenty-six of 86 (30%) patients were colonized with 49 GRGNB. Sixteen patients (19%) had urinary colonization. Multivariate analysis revealed significant associations between rectal or perineal colonization (P less than 0.01), and the presence of a urinary device (82% condom catheters) (P less than 0.05), with urinary colonization. The most common isolates were Providencia stuartii (20), Escherichia coli (nine) and Klebsiella pneumoniae (nine). Twenty-six of 49 isolates carried plasmids. Restriction endonuclease digestion of plasmid DNA was performed for 21. Cross-colonization, as defined by the presence of the identical species with the identical restriction endonuclease digestion profile of purified plasmid DNA found in different patients, was observed for eight of 21 (38%) strains. All were geographically clustered. No strains could transfer gentamicin-resistance by conjugation and only two plasmids could transform our E coli recipient to gentamicin resistance. One E coli plasmid was identical to two Citrobacter freundii plasmids and a P stuartii plasmid isolated from three different patients. This 105 kb plasmid is conjugative and encodes resistance to ampicillin, carbenicillin, tetracycline, and sulfonamides. Thus, 57% of strains were cross-colonizing or contained identical R-plasmids. Southern hybridization using a 1 kb TEM-1 gene probe demonstrated sequences homologous to this probe in five of five nursing home plasmids examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

One-day treatment of vulvovaginal candidiasis with a 500-mg clotrimazole vaginal tablet compared with a three-day regimen of two 100-mg vaginal tablets daily.

In a randomized, double-blind trial, the efficacy and safety of a new single-dose clotrimazole vaginal tablet were compared with that of three-day clotrimazole therapy. Forty-two patients with clinically and mycologically confirmed vulvo-vaginal candidiasis received either one 500-mg clotrimazole tablet for one day or two 100-mg tablets daily for three days. Follow-up visits were performed approximately one week and one month after treatment. Thirty-six patients were evaluated for drug efficacy. There was no significant difference in clinical and mycological responses to the two regimens (P = 1.00, Fisher's exact test). At the final visit, 16 (89%) of the 18 patients receiving one-day treatment showed mycological and clinical clearance of infection, as compared to 15 (83%) of the 18 patients receiving three-day therapy. One patient in the three-day treatment group presented moderate edema of the vulva which was judged to be remotely related to treatment. The findings indicate that a single 500-mg tablet of clotrimazole is as effective and safe in the treatment of vulvovaginal candidiasis as a three-day course of 200 mg/day.

Adult↗
PubMed1985

Therapeutic results obtained in vaginal mycoses after single-dose treatment with 500 mg clotrimazole vaginal tablets.

A multicenter, double-blind study of 103 patients with clinically and mycologically documented vulvovaginal candidiasis compared single-dose treatment with a 500 mg clotrimazole vaginal tablet to 3-day treatment with two 100 mg clotrimazole vaginal tablets administered daily. Patients were examined 5 to 10 days (visit 2) and at least 27 days (visit 3) post treatment. At visit 2, mycologic and clinical examinations were negative in 43 of 48 efficacy-evaluable patients receiving clotrimazole, 500 mg (90%), versus 42 of 47 efficacy-evaluable patients receiving clotrimazole, 200 mg (89%). Similarly, at visit 3, 75% of patients receiving clotrimazole, 500 mg, had treatment success versus 72% receiving clotrimazole, 200 mg. There were no significant intergroup treatment differences, indicating that single-dose treatment with clotrimazole, 500 mg, is equipotent to the multidose regimen.

Adolescent↗
PubMed1985

Type II collagen mediated autoimmune middle ear disease: eustachian tube disease, otitis media with effusion and tympanosclerosis.

Intact Eustachian tube and tympanic cavity functions are essential for normal middle ear physiology. Type II collagen is an essential component of ear tissue. Autoimmune response to this type II collagen produces sensorineural hearing loss, vestibular dysfunction, endolymphatic hydrops, otospongiosis-like lesions, Eustachian tube inflammation and Eustachian tube chondritis. In addition, these autoimmune responses occasionally produce otitis media with effusion (not infectious). Tympanosclerosis, which is a frequent sequelae of otitis media with effusions, was also induced by type II collagen immunization together with surgical incision of the tympanic membrane. The exact mechanisms of this type II collagen autoimmune mediated middle ear disease are not clear. However, the animals thus induced have higher antibody titers and cell mediated immune responses to type II collagen. The tympanic membrane showing tympanosclerosis also had C3 and Ig deposits. All the animals with otitis media with effusion induced by type II collagen immunization also had Eustachian tube disease. This could be due to a malfunction of the Eustachian tube. Thus, this model might provide a rational approach for the study of otitis media with effusion associated with vasculitis. Further studies are needed to elucidate the immunologic mechanism involved in the pathogenesis of otitis media with effusion.

Animals↗
PubMed1985

Type II collagen induced autoimmune salpingitis in the rat.

Previous studies showed type II collagen induced autoimmune salpingitis in Wistar rats. In this study we increased the number of animals and investigated whether or not type II collagen induced salpingitis is transferable by immune sera. Histopathological observations of salpingitis in the serum transferred rats were similar to those observed in the immunized rats but the degree of otopathological changes was less than that of immunized rats. Electronmicroscopic findings indicate an increased permeability in the capillaries and intercellular space and cellular infiltration in the submucosa of the immunized rats.

Animals↗
PubMed1983

Type II collagen-induced autoimmune endolymphatic hydrops in guinea pig.

Endolymphatic hydrops was induced in guinea pigs by immunizing them with native bovine type II collagen. Histopathologic changes consisted of moderate extension of the Reissner's membrane, spiral ganglion degeneration, atrophied organ of Corti, and mild atrophy of the surface epithelium in the endolymphatic duct. These findings suggest that an immune response directed against type II collagen--a type of collagen found in the membranous labyrinth, subepithelial layer of the endolymphatic duct, spiral ligament, and enchondral layer of the otic capsule--may induce endolymphatic hydrops.

Animals↗
PubMed1983

Epidemiology of gentamicin-resistant, gram-negative bacillary colonization in a spinal cord injury unit.

A prospective epidemiological survey of a spinal cord injury unit for gentamicin-resistant, gram-negative bacilli was undertaken. The initial survey of the unit suggested a low level of cross-infection involving Pseudomonas aeruginosa and Providencia stuartii. However, a longitudinal study of new admissions revealed that only 13 of 52 nosocomial acquisitions could be considered to be due to cross colonization. Comparison of data on antibiotic use did not suggest selective pressure for resistant endogenous flora. Nosocomial acquisition was directly related to the length of the hospital stay. Antibiotic susceptibility testing of gentamicin-resistant, gram-negative bacilli showed only minor differences between nosocomial isolates and those present during the initial survey. Of the usual antimicrobial agents, amikacin, carbenicillin, and cefoxitin were the most active against all organisms, with the exception of Serratia spp. Of the new beta-lactams, ceftazidime and imipemide (N-formimidoyl thienamycin) were most active.

Acinetobacter↗
PubMed1982

Effect of fatty acid modification of cultured hepatoma cells on susceptibility to natural killer cells.

Rat hepatoma (Morris 7777) cells modified with either oleic or linoleic acid exhibited greater susceptibility to normal spleen cell-mediated lysis in a 16-hr 51Cr release assay. At effector:target cell ratios of 300:1, the specific lysis of fatty acid-enriched target cells (cultured for 2 days in fatty acid-supplemented medium) by the normal rat spleen cells was 60% higher than the untreated target cells (P less than 0.01). Prolonging the culture in fatty acid-supplemented medium up to 6 days produced similar effects. Analysis of the fatty acid composition of cellular lipids revealed that an elevation of oleic or linoleic acid was the only significant alteration in the hepatoma cells grown in the oleic or linoleic acid-supplemented medium, respectively. The percentage of the acids was increased in the total cellular phospholipids, the choline, ethanolamine, serine, and inositol phosphoglyceride fractions, and the neutral lipids. In conclusion, we suggest that the elevation of oleic acid and linoleic acid contents in the membranes of the fatty acid-modified hepatoma cells may contribute to the increased susceptibility of these cells to natural killer cell-mediated cytotoxicity.

Animals↗