Biomedical subjects
Publications and source records attributed to G Hall.
We report the use of a twist drill method for placement of external ventricular drains and ventriculoperitoneal shunts. We have found this method to be efficient and safe, and provides an excellent cosmetic effect.
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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.
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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.
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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.
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.
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
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.
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.
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.
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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.
In Experiment 1 rats received initial training in which delivery of a sucrose pellet was signalled by an auditory cue. This cue was then paired with shock in a second phase of training. In a test the rats showed an unwillingness to perform an instrumental response that yielded the sucrose pellet. This was interpreted as indicating that the associatively activated representation of the pellet had acquired aversive properties during the shock-reinforced stage of training. Experiment 2 replicated this mediated conditioning effect making use of a Phase 1 training procedure, modelled on that used by Honey and Hall (1989) to demonstrate acquired equivalence of cues, in which two auditory cues were each used to signal sucrose pellets. A further test revealed that this training resulted in enhanced generalization between these two cues. It was argued that this effect is mediated by the conditioned aversive properties of the common associate of the two auditory cues.
In macaques, the route of immunization has a profound effect on the immune response. Augmenting rectal or vaginal immunization with oral or nasal immunization enhanced the secretory IgA, serum IgG, and T cell responses. However, targeted iliac lymph node (TILN) immunization with recombinant simian immunodeficiency virus (SIV) gp120 and p27 elicited the most consistent mucosal antibody responses in the rectum, vagina, urine, seminal fluid, and blood. Both mucosal and TILN immunization induced specific CD4+ T cell proliferative responses in the iliac lymph nodes, which drain these mucosal surfaces, and in the splenic and circulating T cells. Rectal mucosal challenge with cell-free SIV induced total protection in 4 of 7 macaques that were immunized by the TILN route, and, compared with unimmunized macaques or those immunized by the mucosal route (P<.001), it induced a >90% decrease in virus load in 3 of them. Protection from mucosal rectal infection with SIV was significantly associated with an increase in the CD8 suppressor factor (which was generated by the iliac lymph node), RANTES, and MIP-1beta (P<.01).
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OBJECTIVE: To investigate 1-year effects of hormone replacement therapy (HRT) on ambulatory blood pressure (ABP) and lipoprotein levels in postmenopausal women with coronary artery disease (CAD). METHODS: Sixty patients at a mean age (+/- SD) of 59 +/- 7 years were randomized into three groups: conjugated equine oestrogens (CEE) 0.625 mg daily (n = 20), 50 microg 17beta-oestradiol transdermally (TTSE) per 24 h (n = 20) or placebo (n = 20) for 18 days, then combined with medroxyprogesterone acetate 5 mg for 10 days. Each cycle of 28 days was repeated for one year. RESULTS: Night-time systolic ABP had decreased by 9.6% (P= 0.0075) in 15 of 18 women in the CEE group and by 22% in 12 of 13 women (P = 0.0034) in the placebo group after 1 year. In the CEE group, a 4.6% rise in daytime systolic ABP (P< 0.05) and a 4.2% rise in night-time systolic ABP (P< 0.05) appeared from baseline to 6 months in 13 of 18 women. In the CEE group (14 women analysed), high-density lipoprotein levels showed a 15.8% increase (P= 0.0018) in 13 women, low-density lipoprotein levels a 15.2% decrease (P= 0.0129) in 12 women and total cholesterol levels a 7.5% decrease (P = 0.057) in 11 women after 1 year. Triglyceride levels showed no changes. In the TTSE group and in the placebo group, with 12 and 13 women analysed respectively, no significant changes appeared. CONCLUSIONS: One year of HRT in patients with CAD does not influence ABP. Oral HRT induces beneficial effects on lipoprotein levels.