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Biomedical subjects

C Walters

Publications and source records attributed to C Walters.

At least 37 records · Page 2Linked to original sources
PubMed1995

Tryptase and IgE concentrations in the respiratory tract of infants with acute bronchiolitis.

It has been proposed that a specific IgE response contributes to the immunopathology of acute respiratory syncytial virus (RSV) bronchiolitis but previous work has been difficult to replicate. Indirect evidence that might support this contention was sought by measuring total IgE concentrations in bronchoalveolar lavage (BAL) samples obtained from intubated infants and by attempting to detect mRNA for IgE in cells obtained from both the upper and lower respiratory tract. Evidence of significant mast cell activation was sought by measuring tryptase concentrations in BAL fluid and serum. Detectable concentrations of IgE were found in two of seven BAL samples obtained more than five days after intubation and mRNA for IgE was demonstrated in three of six BAL samples and three of six samples obtained from the upper respiratory tract. Tryptase was detectable in 11 of 12 BAL samples with the two highest values detected on day 1. These values were raised compared with control samples but were not such to suggest that mast cell degranulation is the major contributor to the inflammatory process. These results suggest that IgE may be produced in the airways of infants in response to RSV infection. The relationships between IgE production, RSV infection, and symptoms of acute bronchiolitis remain obscure.

Acute Disease↗
PubMed1994

The anaphylaxis hypothesis of sudden infant death syndrome (SIDS): mast cell degranulation in cot death revealed by elevated concentrations of tryptase in serum.

A series of cases of sudden unexpected post-neonatal deaths from two centres in the UK have been investigated for evidence of mast cell activation using the biochemical markers tryptase and 9 alpha,11 beta-PGF2. Tryptase was selected as a possible marker because it is a component of mast cell secretory granules and, unlike histamine, it is not released from basophils. The prostaglandin 9 alpha,11 beta-PGF2 is an initial and pharmacologically active metabolite of PGD2, the major mast cell-derived cyclooxygenase product. This prostaglandin was chosen to serve as a marker of newly generated mediator release. In the study, unexplained infant deaths were associated with a higher concentration of tryptase in serum compared with cases of unexpected, but subsequently explained death. However, 9 alpha,11 beta-PGF2 was found to be an unsuitable post mortem marker in this situation. These results provide direct evidence that mast cell degranulation, possibly as a result of anaphylaxis, may be occurring around the time of death in some cases of cot death.

Anaphylaxis↗
PubMed1993

The effect of local hyperthermia on allergen-induced nasal congestion and mediator release.

BACKGROUND: Local hyperthermia reduces mast cell degranulation, the severity of acute lung injury, and exercise-induced asthma and decreases symptoms of rhinitis. We have investigated the effect of local hyperthermia on mast cell degranulation and symptom generation in allergic rhinitis to assess its effect and mechanism of action within the nose. METHODS: In a randomized, double-blind, placebo-controlled, crossover study, 10 subjects with rhinitis were treated for 30 minutes with local hyperthermia or placebo, which was followed 30 minutes later by nasal allergen challenge. During the first two visits nasal lavages were performed to assess vascular leakage and mediator release. During the last two visits nasal airway resistance, the number of sneezes, and mucus secretion were monitored. RESULTS: Local hyperthermia significantly reduced both nasal airway resistance (p < 0.05) and vascular leakage (p < 0.02) but had no significant effect on the number of sneezes, on mucus secretion, or on tryptase release. CONCLUSION: Local hyperthermia reduces allergen-provoked nasal blockage and vascular leakage but has no effect on sneezing, rhinorrhea, or tryptase release. Nasal blockage occurs predominantly via newly formed lipid mediators and kinins, whereas sneezing and rhinorrhea occur predominantly via preformed mediators. We propose that local hyperthermia inhibits newly formed mediator production or release or reduces the sensitivity of the vasculature to inflammatory mediators in general. Further investigation into the mechanisms and potential uses of local hyperthermia is warranted.

Adult↗
PubMed1992

Circulating histamine and eosinophil cationic protein levels in nocturnal asthma.

1. To investigate the role of mast cells and eosinophils in the pathogenesis of nocturnal asthma, the plasma methylhistamine concentration, serum eosinophil cationic protein level and peak expiratory flow rate were measured 2-hourly for 24 h in 10 patients with nocturnal asthma and in 10 healthy control subjects. Nocturnal asthma was defined as at least one nocturnal awakening per week due to cough, wheeze or breathlessness with an average overnight fall in peak expiratory flow rate of at least 15% during a 2-week run-in period. 2. The lowest peak expiratory flow rate occurred at 02.00-04.00 hours in the group with nocturnal asthma, whose overnight fall in peak expiratory flow rate was 29 +/- 5% in comparison with 5 +/- 1% (means +/- SEM) in the normal subjects. 3. Plasma methylhistamine levels at night (0.200-04.00 hours) were lower than during the day (10.00-20.00 hours) in both asthmatic patients and normal subjects (asthmatic patients: day, median 0.22 ng/ml, 95% confidence intervals 0.18-0.34 ng/ml; night, 0.17 ng/ml, 0.13-0.24 ng/ml; P < 0.01; normal subjects: day, 0.31 ng/ml, 0.24-0.41 ng/ml; night, 0.24 ng/ml, 0.21-0.33 ng/ml; P < 0.01). 4. The serum eosinophil cationic protein level was higher by day (30 ng/ml, 8-47 ng/ml) than by night (21 ng/ml, 5-34 ng/ml; P < 0.04) in the group with nocturnal asthma, but did not change significantly with the time of day in the normal subjects (day: 8 ng/ml, 4-14 ng/ml; night: 8 ng/ml, 5-21 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Inflammatory mediators and cellular infiltration of the lungs in a guinea pig model of the late asthmatic reaction.

Alterations in cell numbers, vascular permeability, and concentrations of various inflammatory mediators in the lung were measured in a guinea pig model of the late asthmatic reaction. Animals sensitized by inhalation of ovalbumin were challenged with an aerosol of ovalbumin or saline, and bronchoalveolar lavage fluid (BALF) and peripheral blood were collected after periods ranging from 5 min to 72 h. Increased vascular leakage within the lungs was indicated by elevated BALF/plasma albumin ratios at all time points, and was maximal 6 h after challenge. There were increased numbers of eosinophils in BALF by 6 h after challenge and they remained elevated at least until 72 h. A corresponding increase in the proportion of blood leukocytes represented by eosinophils was observed at 6 and 17 h, which suggests that these cells may be drawn to the lung following their release into the circulation, but by 72 h the proportion in blood had returned to normal. A transitory neutrophilia was evident in BALF and blood 6 h after allergen exposure, but there were no allergen-induced changes in BALF numbers of macrophages, lymphocytes, epithelial cells, or mast cells (as assessed by concentrations of cell-associated histamine). beta-Glucuronidase activity was significantly increased in BALF of guinea pigs at 2 h and 17 h following challenge. The degree to which eicosanoids can be recovered in BALF was investigated by instilling a range of tritiated compounds into the lungs of normal guinea pigs at the time of lavage. Ratio high-performance liquid chromatography revealed that there had been little metabolism of the eicosanoids recovered in BALF. However, there was evidence for a rapid removal of these mediators from the lung, a process which will militate against their accurate quantitation in BALF. Histamine, prostaglandin D2, and thromboxane B2 were detected in BALF but did not differ between treatment groups, and levels showed no simple relationship with the other inflammatory changes measured.

Albumins↗
PubMed1989

A young woman with abdominal pain.

Patients rarely present with solely a physical problem. While psychological overlay and social factors expand the differential diagnosis and modify management, physical dangers should not be forgotten. Disruption of the family unit isolates individuals and requires extra consideration from the caring practitioner, as in the case of Sarah Leigh.

Abdominal Pain↗
PubMed1988

Chronic atrophic gastritis and risk of N-nitroso compounds carcinogenesis.

Chronic atrophic gastritis is considered a precancerous condition for carcinoma of the stomach. To evaluate the correlation between progressive alterations in the mucosa and gastric juice microenvironmental factors, retained involved on N-nitroso compounds carcinogenesis, detailed analyses of biochemical and microbiological parameters such as pH, total viable counts (TVC), nitrate reductase positive bacterial counts (NRPBC), nitrite (NO2-) and thiocyanate (SNC-) levels, were carried out on 56 fasting gastric juices samples obtained at endoscopy from 28 patients with chronic atrophic gastritis (CAG), 14 with gastric cancers (GC), and 14 normal controls (NC). The mean values of pH, nitrite, TVC, and NRPBC were significantly lower in the juices of NC than in those of CAG and GC patients. Furthermore, the mean levels of the same parameters were higher in GC than in CAG juices. No significant difference was found in the three groups for SCN- level which principally resulted influenced by smoke habit. The 28 patients with CAG were subdivided into two groups (Group A = Diffuse chronic atrophic gastritis--DCAG; Group B = Multifocal chronic atrophic gastritis--MCAG) according to the involvement of gastric corpus and fundus besides antrum by a process of mucosal atrophy. The mean levels of pH, nitrite, TVC, and NRPBC were significantly higher in MCAG than in normal controls but statistically lower in reference to DCAG and cancers. In these two groups no difference was found for the same variables. The percentage of contaminated juices was higher for DCAG and cancers in respect to MCAG but no difference was found between DCAG and neoplastic stomachs. The results of this study suggest that the DCAG could be considered as the chronic atrophic gastritis type more exposed to the risk of N-nitroso compounds carcinogenesis.

Adult↗
PubMed1988

Fixed cutaneous eruptions to seminal-plasma challenge: a case report.

Reactions to human seminal plasma may present as immediate hypersensitivity, cell-mediated hypersensitivity, or fixed eruptions. There are no typical responses to semen. An abnormal skin lesion or systemic response after intercourse may be the only clue to identifying those who are reacting to semen. The use of condoms has proven to be the most consistent preventive modality. However, the use of condoms is unacceptable to some regardless of the relief provided. Although conventional therapy for hypersensitivity reactions to human seminal plasma is suboptimal, one should be aware of MA in the treatment of an atypical cause of human seminal plasma induced reactions.

Adult↗
PubMed1985

Ultrasonographic assessment of luteinized unruptured follicle syndrome in unexplained infertility.

Ultrasound can be used to monitor the growth and rupture of the dominant follicle. Thirty-three patients with unexplained infertility underwent serial sonography (mean, 3.2 scans/cycle) for luteinized unruptured follicle syndrome (LUFS). The incidence of LUFS was 9% (three patients) in the initial scan cycle. Three patients (9%) demonstrated rupture of a follicle significantly smaller than the mean (22.1 mm) (z less than 0.01) in the initial scan cycle. At standard radiology fees ($7000 +/ diagnosed LUFS) the cost/benefit ratio of this method of diagnosis will be controversial. It is suggested that scanning at reduced fees in the gynecologist's office, particularly in conjunction with postcoital tests, would decrease cost and increase the potential benefit.

Ambulatory Care↗
PubMed1984

Suicide and the MMPI: a cross-validation of predictors.

Compared a suicide-completion group to a psychiatric control sample on the 13 traditional MMPI scales, three experimental item pools, and eight profile patterns earlier described as indicative of suicidal tendencies (N = 84). Also compared the frequencies with which the groups endorsed each of the 566 MMPI items. The number of resulting significant differences was less than chance. The results argue against the use of the MMPI to predict suicide at this time.

Adult↗
PubMed1983

Collagen crosslinks in human dentin: increasing content of hydroxypyridinium residues with age.

The hydroxypyridinium crosslinks of collagen are believed to derive from reducible, divalent crosslinks. To study this concept further, both types of crosslink were quantified as a function of age in dentin, a tissue thought to have minimal collagen turnover. Human (5, 15, 28 and 56 years) and bovine (fetal and adult) root dentin was analyzed by a procedure that measures both hydroxypyridinium and reducible crosslinks on the amino acid analyzer. In human dentin, hydroxypyridinium crosslinks increased with age and became the predominant crosslinks as the two reducible residues, dehydrodihydroxylysinonorleucine and dehydrohydroxylysinonorleucine, diminished. Similarly in adult bovine dentin, hydroxypyridinium residues were sixfold more concentrated than in fetal bovine dentin. Borohydride treatment of tissue did not influence the measured content of hydroxypyridinium residues. The analyses also ruled out natural reduction as a stabilizing reaction for the divalent, reducible crosslinks. Though hydroxypyridinium residues became the major aldehyde-mediated crosslinks of adult dentin collagen, significant levels of reducible crosslinks remain throughout the tooth's adult life.

Adolescent↗
PubMed1983

Intracochlear electrical stimulation of normal and deaf cats investigated using brainstem response audiometry.

Brainstem response audiometry for intracochlear electrical stimulation of normal-hearing and deafened cats was investigated. In normal cochleas the brainstem response amplitude grew slowly near threshold as a current-amplitude dependent process, identified as electrophonic in origin. This terminated in a rapidly growing charge-dependent process at approximately 20 dB above threshold, identified as direct electrical stimulation of the auditory nerve. Small levels of white noise (25-35 dB SPL) were sufficient to mask most of the electrophonic response, leaving the direct stimulation process essentially unmodified. In cochleas damaged with d.c. currents and loud sounds, only a rapidly growing charge-dependent process was observed which grew similarly to that in normal-hearing cats but occurred at lower currents. This indicates that possibly the electrical properties of the cochlea were altered in the deafening process, suggesting the inadequacy of normal animals as deaf models for electrical stimulation. Using the technique of derived brainstem responses, it was shown that direct electrical stimulus components were localized to the vicinity of the stimulus electrode with electrophonic components distributed more widely. However, at high currents there was some evidence of the stimulus spreading into the internal auditory meatus.

Animals↗