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Biomedical subjects

B Stone

Publications and source records attributed to B Stone.

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

Chronic sinusitis: characterization of cellular influx and inflammatory mediators in sinus lavage fluid.

Chronic sinusitis is a recurrent disorder commonly found in atopic individuals, yet few studies have explored the role of inflammatory mediators in sinusitis. Sinus lavage fluid from ten patients with chronic sinusitis obtained during endoscopic surgery was analyzed for total cell counts and then assayed for histamine, immunoreactive leukotriene C4/D4/E4 (LTC4/D4/E4), and prostaglandin D2 (PGD2). All ten patients had been unresponsive to medical treatment, including oral corticosteroids in most cases. High concentrations of histamine, LTC4/D4/E4 and PGD2 were found in sinus fluid and were comparable to levels seen in nasal secretions of allergic rhinitis patients following allergen challenge. In the sinus fluid, inflammatory cells were predominantly neutrophils with only low percentages of mast cells, basophils or eosinophils. On the basis of the histamine and PGD2 concentrations in sinus fluid, we conclude that mast cell/basophil activation does occur in chronic sinusitis and may contribute to the persistent inflammation present in sinusitis.

Adolescent↗
PubMed1994

Targeted RNA fingerprinting: the cloning of differentially-expressed cDNA fragments enriched for members of the zinc finger gene family.

We have developed and applied a modification of an 'RNA Fingerprinting' protocol previously published by Welsh and McClelland (Nucleic Acids Research 19: 5275-5279 1991) such that cDNA fragments which are both differentially-expressed and enriched for members of a specific gene family can readily be identified. cDNA fragments were amplified with an arbitrary primer initially used in the reverse transcription reaction in combination with a member of a primer set which corresponded to a conserved region within a specific gene family. This technique was used to isolate cDNAs encoding a recently described protein kinase as well as an unknown gene that contained a zinc finger. Several other known genes that contained a zinc finger domain and that were differentially-expressed were also isolated.

Amino Acid Sequence↗
PubMed1993

Respiratory changes and structure of sleep in young high-altitude dwellers in the Andes of Peru.

Sleep organisation in eight young [mean (SD); 20.9 (2.6) years] Peruvian high-altitude residents was studied in a laboratory in Cerro de Pasco at 4300 m. Electroencephalograms, electromyograms, electro-oculograms, electrocardiograms, respiratory movements and arterial oxygen saturation were recorded on an 8-channel Medilog recorder and analysed later in England. Haematocrits ranged from 48% to 64% [57.9 (5.6)%]. The amount of slow wave rapid eye movement (REM) sleep was similar to that reported in young lowlanders sleeping at sea level but very different to the disturbed sleep in visitors sleeping at high altitude. All the Peruvians showed episodes of periodic breathing and respiratory apnoeas [29 (15) night-1] resulting in marked arterial oxygen desaturation [81 (4.5)%; changes of 6 (2.5)%]. These events occurred either during stage 2 or REM sleep and were more frequent in those with lower haematocrits. The amount of wakefulness during the night was 2-3 times greater than would be expected in an age-matched lowland population at sea level. The awakenings were strongly associated with apnoeas (P < 0.02) but were negatively correlated with haematocrit, although this was only significant for seven of the subjects (P < 0.05).

Adult↗
PubMed1993

The laryngeal mask in cardiopulmonary resuscitation in a district general hospital: a preliminary communication.

For a period of 13 months adult patients sustaining a cardiopulmonary arrest in the Royal East Sussex Hospital, Hastings, were attended by nursing staff and Operating Department Assistants (ODAs) specially trained in the use of the laryngeal mask (LM) as an airway adjunct. The LM was used 41 times in 40 patients. The LM failed on only two occasions, and was successful in three cases where endotracheal intubation proved impossible. No instances of aspiration were directly attributable to LM use. LM trained staff adopted its use enthusiastically, and skills acquired during training appeared not to fade over the period of the study. These results are considered to justify the performance of a large-scale trial of use of the LM in cardiac arrest patients.

Aged↗
PubMed1993

Sacral root stimulation for controlled micturition: prevention of detrusor-external sphincter dyssynergia by intraoperative identification and selective section of sacral nerve branches.

Electrical stimulation of the S2 nerve root can be used to produce detrusor contraction and voiding in patients with spinal cord injury, but concurrent stimulation of the external urethral sphincter causes detrusor-sphincter dyssynergia. This has been managed with a second surgical procedure, peripheral transection of the pudendal nerve. In this study, performed in dogs after spinal cord transection, laminectomy and ventral foraminotomy permitted tracing of the S2 root into the pelvis, where its branches were identified by electrical stimulation and urodynamic recording. The pudendal (somatic) branch was sectioned; the autonomic branch innervating the detrusor was preserved. Electrical stimulation of the proximal S2 root then produced detrusor contraction without contraction of the external urethral sphincter. This approach, which requires a single operation and spares pudendal nerve functions mediated by nerve roots other than S2, may enable a neurostimulator to provide effective voiding, without detrusor-external sphincter dyssynergia, in man.

Animals↗
PubMed1991

Reactions to argasid tick bites by island residents on the Great Barrier Reef.

OBJECTIVE: To attribute a cause and quantify allergic-like symptoms observed among island residents. DESIGN: Skin prick tests and intradermal injections with ultraviolet-irradiated, filtered (0.22 microns) whole-body homogenates of the soft tick, Ornithodoros capensis, were used to reproduce experimentally the symptoms observed. SETTING: Heron Island, Great Barrier Reef, Australia. PARTICIPANTS: Island residents were designated as such after having spent more than 1 month on the island during the summer seabird breeding season. INTERVENTIONS: Control measures were instigated using a residual insecticide, delta-methrin, sprayed inside sleeping quarters. MAIN OUTCOME MEASURES: Acaricide spraying reduced (X2 = 4.42; P less than 0.05) the number of island residents complaining of having been bitten by ticks, yet was considered an inefficient control measure as 67% reported being attacked by ticks after spraying. RESULTS: Among 97 island residents, elevated total IgE levels were associated with reaction to tick bite in 11 cases (X2 = 27.17; P less than 0.001), but were not of reliable diagnostic value. Symptoms included intense pruritus, blistering (a major feature), erythema, weeping lesions, lymphangitis, dull ache, rheumatic pain and general lassitude, and intense discomfort. Sera from two of four volunteers with known reactions to O. capensis and one of four others with reactions to the Australian paralysis tick, Ixodes holocyclus, cross-reacted with antigens from a total of four of six biting/stinging and non-biting arthropods (radioallergosorbent tests). CONCLUSIONS: Symptoms associated with reactions to tick bite peaked in severity at 35-40 hours and thus the response was most likely delayed type IV hypersensitivity.

Animals↗
PubMed1991

Age-dependent alterations in the efficacy of phenylephrine-induced contractions in vascular smooth muscle isolated from the corpus cavernosum of impotent men.

Steady-state contractile responses elicited by phenylephrine activation of the alpha 1-adrenergic receptor subtype were studied in vascular smooth muscle strips isolated from the corpus cavernosum of impotent men. The dissociation constant of phenylephrine was determined by the method of partial irreversible receptor inactivation over a wide range of alpha 1-adrenergic receptor alkylation levels. Statistical analysis of mean population values revealed a significantly greater mean efficacy for phenylephrine-induced contractions in older patients (60-73 years old) than in younger patients (40-59 years old), in the absence of similar alterations in the mean phenylephrine dissociation constant (affinity). In addition, there was no significant effect of the diabetic state on the mean phenylephrine affinity or efficacy estimates. However, despite the absence of age- or pathology-dependent variations in agonist affinity, as assessed by group mean calculations, a detailed examination of all isolated tissues on an individual basis revealed that the phenylephrine affinity estimates varied over a range of almost two orders of magnitude. Furthermore, a linear regression analysis revealed a highly significant positive correlation between agonist affinity and the location of the phenylephrine concentration-response curve, which was characterized by a slope significantly less than unity. In conclusion, an increased efficacy of phenylephrine-induced contractions in vitro is consistent with the hypothesis that augmented corporal vascular smooth muscle contractility in vivo may contribute to the pathophysiology of impotence in older patients.

Adrenergic alpha-Agonists↗
PubMed1988

Occurrence of a spontaneous luteinizing hormone surge in superovulated cycles--predictive value of serum progesterone.

A preovulatory increase in serum progesterone (P) precedes the occurrence of an endogenous luteinizing hormone (LH) surge in a majority of women. This study evaluates whether a single daily measurement of serum P could reliably identify a spontaneous LH surge in women undergoing controlled ovarian hyperstimulation. Eighty-four infertile women received either clomiphene citrate and human menopausal gonadotropin (hMG), or hMG alone. Serum P levels were increased significantly the morning of the day of an endogenous LH surge (P less than 0.01). A 2-fold rise in the serum P levels was associated with a predictability of 64.4% of a LH surge; however, a 4-fold increase in serum P could accurately predict a spontaneous endogenous LH discharge in 93.3% (P less than 0.001) of cases.

Chorionic Gonadotropin↗
PubMed1988

An alternate approach to controlled ovarian hyperstimulation in "poor responders": pretreatment with a gonadotropin-releasing hormone analog.

Pharmacologic hypophysectomy was induced with a subcutaneous injection of leuprolide acetate before the administration of exogenous gonadotropins for multiple follicle development in 27 women who had previously responded poorly to conventional controlled ovarian hyperstimulation (COH). Pituitary desensitization occurred within 6 days and concurrent COH with exogenous gonadotropins resulted in an enhanced yield of oocytes in comparison to previous COH attempts (P less than 0.05). Fertilization and pregnancy rates also were higher with gonadotropin-releasing hormone agonist (GnRHa) treatment (P less than 0.01). The administration of leuprolide acetate effectively suppressed endogenous gonadotropin secretion when initiated in the follicular or luteal phase of the menstrual cycle. GnRHa therapy can appreciably facilitate the management of gonadotropin therapy, and increase the probability of oocyte collection and pregnancy.

Chorionic Gonadotropin↗
PubMed1987

Dysphagia as the presenting symptom of recurrent breast carcinoma.

Esophageal obstruction secondary to recurrent breast carcinoma is not widely recognized. Frequently, the esophageal narrowing is attributed to a benign process, resulting in delays of diagnosis and treatment. Such a case prompted this report and review of the literature.

Breast Neoplasms↗
PubMed1986

The relation between survival and age at diagnosis in breast cancer.

We analyzed the relation between age at diagnosis and relative survival (ratio of observed to expected survival) in 57,068 women in Sweden in whom breast cancer was diagnosed in 1960 to 1978 (about 98 percent of all cases). Women who were 45 to 49 years old had the best prognosis, with a relative survival exceeding that of the youngest patients (less than 30 years) by 7.6 to 12.9 percent at different periods of observation. Relative survival declined markedly after the age of 49--particularly in women aged 50 to 59--and the oldest women (greater than 75) had the worst rate. The difference in relative survival between those older than 75 and those 45 to 49 increased from 8.6 percent at 2 years to 12.2, 20.3, and 27.5 percent after 5, 10, and 15 years of follow-up, respectively. The long-term annual mortality rate due to breast cancer approached 1 to 2 percent at the premenopausal ages but exceeded 5 percent throughout the period of observation in the oldest age group. An understanding of the biologic basis for the complex relation between age and prognosis might provide a better understanding of the natural history of breast cancer in women.

Adult↗