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Biomedical subjects

G Hall

Publications and source records attributed to G Hall.

At least 55 records · Page 3Linked to original sources
PubMed2000

Should all patients with candidaemia have an ophthalmic examination to rule out ocular candidiasis?

PURPOSE: To determine the incidence of ocular candidiasis and length of ophthalmic follow-up required to rule out ocular candidiasis in candidemia patients. METHODS: We prospectively studied patients with candidemia at our institution. Eligibility criteria included a dilated ophthalmological examination within 72 h of fungemia. Patients without ocular candidiasis on initial examination had follow-up dilated ophthalmoscopy performed at 1, 2, 4, 12 and 24 weeks. RESULTS: Between May 1996 and March 1997 a total of 50 patients with fungemia were identified of whom 31 were included in the study; 15 excluded patients died before an initial examination was performed. The overall incidence of ocular candidiasis was 26% (8/31 patients), all manifested as chorioretinitis. Five patients (16%) had ocular candidiasis on their initial examination. One of 21 patients (5%) without ocular candidiasis on initial examination developed ocular candidiasis within 1 week. Two of 16 patients (13%) without ocular candidiasis on initial examination or at 1 week follow-up developed ocular candidiasis within 2 weeks. No evidence of ocular candidiasis occurred in the 12 patients with follow-up at 4 weeks, the 8 patients with follow-up at 12 weeks and the 4 patients with follow-up at 24 weeks. CONCLUSION: The incidence of ocular candidiasis among hospitalized patients is clinically significant. We recommend ophthalmological follow-up for development of ocular candidiasis for at least 2 weeks after an initial negative eye examination.

Aged↗
PubMed2000

High prevalence of diarrhea but infrequency of documented Clostridium difficile in autologous peripheral blood progenitor cell transplant recipients.

Autologous peripheral blood progenitor cell (PBPC) transplant recipients frequently receive multiple antibiotics for neutropenic fever in addition to high-dose chemotherapy. Although there are many possible causes for diarrhea in this population, empiric therapy for possible C. difficile colitis is common in some centers. This study sought to define the frequency of diarrhea and of a positive C. difficile toxin assay in PBPC transplant recipients. Data were collected on 80 patients enrolled in a randomized trial of two different antibiotic regimens during PBPC transplant. Data included the presence or absence of diarrhea, all microbiologic studies performed during the transplant admission, and all antimicrobials administered during the transplant admission. Of 80 patients enrolled, 61 (76.3%) developed diarrhea. Only 3/61 (4.9%) had a positive C. difficile toxin assay. A total of 122 C. difficile toxin assays were performed; for each positive C. difficile assay, 41 stool samples were analyzed. Twenty courses of oral metronidazole (18/20 empiric) and 10 courses of oral vancomycin (8/10 empiric) were given. A total of 25 of 61 patients with diarrhea (41%) received therapy for possible C. difficile. Diarrhea is common during autologous PBPC transplant but a positive C. difficile assay is uncommon. The practice of empiric therapy for C. difficile in this population in a non-outbreak setting should be re-evaluated. Bone Marrow Transplantation (2000) 25, 67-69.

Administration, Oral↗
PubMed2000

Up-regulation of beta-chemokines and down-modulation of CCR5 co-receptors inhibit simian immunodeficiency virus transmission in non-human primates.

A non-cognate mechanism of protection against human immunodeficiency virus-1 (HIV-1) infection involves up-regulation of beta-chemokines, which bind and may down-modulate the CCR5 co-receptors, thereby preventing transmission of M-tropic HIV-1. The objective of this investigation was to evaluate this mechanism in vivo in non-human primates. Rhesus macaques were immunized by a modified targeted lymph nodes (TLN) route with recombinant simian immunodeficiency virus (SIV) glycoprotein 120 (gp120) and p27 in alum, and adsorbed recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) with either interleukin (IL)-2 or IL-4. Immunization induced significant increases in the concentrations of CD8 cell-derived suppressor factor (CD8-SF), regulated on activation normal T cells expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha and MIP-1beta, and down-modulation of the proportion of cells expressing CCR5 (r = 0.737, P<0.05). The macaques were then challenged with SIVmac 220 by the rectal mucosal route. The plasma SIVmac RNA showed a significant inverse correlation with the CD8-SF or the concentration of the three beta-chemokines (r = 0.831 and 0.824, P<0.01), but a positive correlation between the proportion of CCR5+ cells and SIVmac RNA (r = 0.613, P = 0.05). These results demonstrate for the first time in vivo that immunization up-regulates beta-chemokines, which may down-modulate CCR5 co-receptors, and both functions are significantly correlated with the viral load. Hence, the non-cognate beta-chemokine-CCR5 mechanism should be considered as complementary to specific immunity in vaccination against HIV.

Animals↗
PubMed2000

Identification of a Mycobacterium bovis BCG auxotrophic mutant that protects guinea pigs against M. bovis and hematogenous spread of Mycobacterium tuberculosis without sensitization to tuberculin.

Tuberculosis remains one of the most significant diseases of humans and animals. The only currently available vaccine against this disease is a live, attenuated vaccine, bacillus Calmette-Guérin (BCG), which was originally derived from Mycobacterium bovis and despite its variable efficacy is the most widely administered vaccine in the world. With the advent of the human immunodeficiency virus-AIDS pandemic concern has been raised over the safety of BCG. Moreover, since BCG sensitizes vaccinated individuals to the tuberculin test, vaccination with BCG prevents diagnosis of infection in vaccinated individuals. Recently, auxotrophic strains of BCG have been generated by insertional mutagenesis which have been shown to be safer than the parent BCG strain following administration to mice with severe combined immunodeficiency disease. These strains have also been shown to give comparable protection against intravenous and intratracheal challenge of BALB/c mice with M. tuberculosis relative to conventional BCG. Here we report that one of these mutants, a leucine auxotroph of BCG, conferred significant protection of the lungs and spleens of guinea pigs infected with M. bovis and protection of the spleens of guinea pigs infected with M. tuberculosis in the absence of a cutaneous hypersensitivity reaction to tuberculin. Therefore, protective immunity to tuberculosis may, at least in part, be achieved without sensitization to the tuberculin skin test. These results indicate that it may be possible to develop a new generation of vaccines based on BCG that are protective, are safe for use in the immunocompromised, and do not preclude the use of the tuberculin skin test in both humans and animals.

Animals↗
PubMed2000

Ciliocytophthoria in clinical virology.

Direct immunofluorescence assays (DFAs) are used in the clinical virology laboratory for the rapid detection of viruses. An assessment of the cellularity of specimens submitted for DFA is necessary for the most effective use of this assay. This assessment ensures that an adequate number of the appropriate cells are present for examination. During this assessment, clinical virologists may encounter unfamiliar cellular elements or cellular fragments. One of these elements, ciliocytophthoria, has been misinterpreted as a parasite in specimens submitted for cytologic testing. We describe a similar case in which a technologist thought that ciliocytophthoria possibly represented a ciliated parasite in a nasopharyngeal specimen sent for respiratory syncytial virus DFA. After a thorough morphologic examination, the staff dismissed the possibility of a ciliated parasite. We confirmed this entity as ciliocytophthoria using morphologic criteria and the Diff-Quik stain. This near misidentification of ciliocytophthoria as a ciliated parasite affords us the opportunity to raise the awareness of clinical virologists about ciliocytophthoria. Additionally, we briefly review useful features for differentiating ciliocytophthoria from the only ciliate parasitic for humans, Balantidium coli. Finally, we present the utility of a commonly used cytologic stain, the Diff-Quik stain, for the confirmation of ciliocytophthoria.

Artifacts↗
PubMed2000

Association of ureaplasma urealyticum with abnormal reactive oxygen species levels and absence of leukocytospermia.

PURPOSE: Ureaplasma urealyticum is a commensal of the lower genitourinary tract of many sexually active adults. The organism is more common in partners of infertile than fertile marriages. We conducted a prospective study at our tertiary care center to confirm a possible association between U. urealyticum and abnormal sperm function parameters. MATERIALS AND METHODS: A total of 50 consecutive male patients seeking general urology consultation for lower urinary tract symptoms characteristic of chronic prostatitis were evaluated. Urine and semen localization cultures were performed with additional semen cultures for U. urealyticum, Chlamydia trachomatis and Mycoplasma hominis. Specimens from 21 healthy men were used as controls. Specimens were analyzed by a computer assisted semen analyzer, and verified manually for concentration, percent motility and morphology. Leukocytospermia was measured by the Endtz test. Semen specimens were also analyzed for reactive oxygen species (ROS), acrosome reaction and mannose binding assay. RESULTS: Of the patients 17 had positive U. urealyticum cultures and the other cultures were negative. Patients with U. urealyticum had significantly higher ROS levels (log [ROS + 1] = 2.52 +/- 0.25) than those without U. urealyticum (1.49 +/- 0.20, p = 0.002) or controls (1.31 +/- 0.19, p = 0.002). Leukocytospermia was detected in only 1 of the 17 (6%) positive specimens and 4 (12%) negative specimens. CONCLUSIONS: Seminal ROS levels are elevated among patients with U. urealyticum. ROS induces lipid peroxidation, which reduces membrane fluidity and sperm fertilization capability, and may be the mechanism by which U. urealyticum impairs sperm function. Absence of leukocytospermia does not exclude U. urealyticum.

Adult↗
PubMed2000

Personal safety and the abuse of staff in a Scottish NHS Trust.

BACKGROUND: An employer's 'duty of care' is enshrined in statute and common law. This responsibility extends to identifying areas of risk to employee's safety and emotional well being. OBJECTIVE: To identify the views of NHS staff on their safety and exposure to assault and other forms of abuse. DESIGN: A survey by questionnaire and semi-structured interview of the staff of an NHS Trust. SETTING: A large Scottish NHS Trust. SUBJECTS: All 5365 staff of the Trust. RESULTS: Two thousand two hundred and ninety four (43%) employees contributed to this survey. With regard to exposure to hazardous substances and serious infection, most staff were satisfied with safety standards and guidelines. Over a 12 month period 23% of the workforce had been assaulted, mainly by patients and 63% had experienced verbal abuse, again, mainly from patients. There were differences among occupational groups but overall 16% had been bullied; 18% had suffered discrimination; 22% had experienced harassment, and 13% had been victimized. Only 42% of individuals reported their most distressing incidents; 56% of them regarded the outcome of their reports as satisfactory. CONCLUSIONS: Staff are generally satisfied with the steps taken to safeguard them against hazardous substances and serious infection. Assault by and abuse from patients is a considerable risk, especially for trained nurses. In terms of bullying, harassment, discrimination and victimization, the abuse of power by colleagues is also a distressing and under-reported phenomenon which needs to be addressed by regular audit and the creation of a climate in which employees feel secure enough to report such abuse and to have faith in the mechanisms set up to deal with such complaints.

Attitude of Health Personnel↗
PubMed1999

Microsporidia infection in transplant patients.

BACKGROUND: Microsporidia are the most common cause of chronic diarrhea in patients infected with human immunodeficiency virus. Patients who have undergone organ transplantation may also be infected. The precise immune defect and the clinical picture in transplant patients have not been studied. METHODS: We report a case of microsporidia infection in a heart transplant patient and review three other cases reported in the literature. RESULTS: Infection in three solid organ transplant patients occurred when the patients were receiving immunosuppressive therapy for rejection 1.5-3 years after transplantation. Patients had chronic diarrhea, vomiting, dyspepsia, and weight loss for 1 month to 3 years. CONCLUSIONS: Microsporidia may be the cause of chronic unexplained diarrhea and gastrointestinal disturbances in transplant patients. Defects in cell-mediated immunity probably play a role in maintaining the chronicity of this infection. Specific screening requests should be made to the microbiology laboratory when microsporidia infection is suspected.

Animals↗
PubMed1999

Molecular Ecological Analysis of Methanogens and Methanotrophs in Blanket Bog Peat.

Abstract Methane production and methane oxidation potential were measured in a 30 cm peat core from the Moorhouse Nature Reserve, UK. The distribution of known groups of methanogens and methane oxidizing bacteria throughout this peat core was assessed. Using 16S rRNA gene retrieval and functional gene probing with genes encoding key proteins in methane oxidation and methanogenesis, several major groups of microorganisms were detected. Methane production and oxidation was detected in all depths of the peat core. PCR amplification and oligonucleotide probing experiments using DNA isolated from all sections of the peat core detected methanotrophs from the groups Methylosinus and Methylococcus and methanogens from the groups Methanosarcinaceae, Methanococcaceae, and Methanobacteriaceae. 16S rDNA sequences amplified with the Methylosinus-specific primer were shown to have a high degree of identity with 16S rDNA sequences previously detected in acidic environments. However, no methanogen sequences were detected by the probes available in this study in the sections of the peat core (above 7 cm) where the majority of methanogenesis occurred, either because of low methanogen numbers or because of the presence of novel methanogen sequences.http://link.springer-ny.com/link/service/journals/00248/bibs/38n3p225.html</hea

Journal Article↗
PubMed1999

Control of breathing in infants born to smoking mothers.

OBJECTIVE: To determine whether infants born to smoking mothers have an abnormal respiratory drive and a blunted ventilatory response to hypoxia. STUDY DESIGN: Sixty-four healthy infants, aged 2 to 24 months, were classified into smoking (n = 19) or non-smoking (n = 45) groups based on maternal smoking habits. Resting ventilation, lung function, and mouth pressure 100 milliseconds after an airway occlusion at the onset of inspiration (P(0.1 )) were measured. The ventilatory response to hypoxia was assessed in 15 infants (6 in the smoking group and 9 in the non-smoking group) while breathing 14% oxygen. RESULTS: Respiratory drive (P(0.1 ) = 4.9 +/- 1.3 cm H(2 )O) was lower in infants in the smoking group compared with those in the non-smoking group (P(0.1 ) = 5.9 +/- 1.2 cm H(2 )O) (P <.05). The time to peak tidal expiratory flow (tPTEF) was also shorter (0.25 +/- 0.04 seconds vs 0.32 +/- 0.09 seconds, P <.05). Infants born to non-smoking mothers showed a significant ventilatory response to hypoxia and a 24.6% increase in P(0.1 ). Infants in the smoking group showed a blunted ventilatory response to hypoxia and no increase in P(0.1 ). A dose-response relationship existed between the number of cigarettes smoked by the mother (0, 1 to 10, >10 per day) and the results for P(0.1 ) and tPTEF. Paternal smoking had no influence on the infant's resting ventilation, respiratory drive, or ventilatory response to hypoxia. CONCLUSIONS: Infants born to smoking mothers have a reduced drive to breathe and a blunted ventilatory response to hypoxia. These findings may contribute to the increased risk of sudden infant death syndrome in these infants.

Analysis of Variance↗
PubMed1999

Analysis of cell surface properties using derivatized agarose beads.

An assay has been developed to analyse cell surface properties using agarose beads derivatized with amino acids, sugars, proteins, and other molecules. The assay is simple and rapid and is useful to identify new cell surface markers. Various species and strains of yeast, paramecium, and Euglena were tested for their ability to bind to over 100 types of derivatized beads. A variety of specificity studies were performed in order to understand the nature of cell-bead binding. Our results indicate that cell-bead binding is often specific enough to distinguish between configurational isomers and spacer sizes and can be blocked by addition of specific molecules to the incubation medium. In some cases, different species or strains differed only by their binding to a single bead type. This simple and rapid assay may help to uncover new cell surface receptors and may lead to the development of clinically useful compounds for therapeutic applications.

Amino Acids↗
PubMed1999

Lipid oxidation in fillets of herring (Clupea harengus) during ice storage.

The influence of ice storage on lipid oxidation, odor, antioxidants, water-soluble catalysts, and microorganisms was investigated in fillets of herring (Clupea harengus) during 15 days. Based on linear regression analyses of the data, significant rises (p </= 0.05) in lipid oxidation products were seen after 2-3 days and in "rancid" odor after 2.5 days. Peroxide value (PV), fluorescent product (FP), and ascorbic acid analyses were the chemical measures most strongly correlated to "rancid" odor (r = 0.97). Antioxidants decreased in the following order: alpha-tocopherol > ascorbic acid > glutathione peroxidase (GSH-px); however, GSH-px correlated best to the development of lipid oxidation products (r(mean) = -0.96). The activity of aqueous pro-oxidants, which were enzymatic in nature to a great extent, had decreased by 75% at day 15. No significant increase in total bacteria was seen until after 7 days. There were major local differences in both composition and stability throughout the fillet. Oxidation proceeded most rapidly in the tissue right under the skin, probably explained by its high initial pro-oxidative activity.

Animals↗
PubMed1999

Listeria monocytogenes tricuspid valve endocarditis with septic pulmonary emboli in a liver transplant recipient.

Listeria monocytogenes has long been known as a pathogen of immunocompromised hosts, including solid organ and bone marrow transplant recipients. Its principal manifestations include bacteremia and meningitis. Endocarditis due to Listeria is far less common and in general affects the left side of the heart. We here report an unusual case of Listeria tricuspid valve endocarditis and septic pulmonary emboli in a sulfa-intolerant liver transplant recipient with a history of relapsing cytomegalovirus (CMV) hepatitis and an indwelling Hickman catheter. The literature on Listeria endocarditis and infections in transplant recipients is reviewed. The possible relationship between susceptibility to Listeria infection and the discontinuation of trimethoprim-sulfamethoxazole prophylaxis is of interest.

Adult↗