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Biomedical subjects

R M Watson

Publications and source records attributed to R M Watson.

At least 73 records · Page 4Linked to original sources
PubMed1993

Factors contributing to dyspnoea during bronchoconstriction and exercise in asthmatic subjects.

The purpose of the present study was to identify: 1) whether dyspnoea during bronchoconstriction and exercise is related, in asthmatic subjects; and 2) to what extent baseline pulmonary function and respiratory muscle strength contribute to dyspnoea under both conditions. One hundred and seventy five consecutive subjects, referred with suspected asthma, rated the intensity of dyspnoea (Borg scale 0-10): 1) during the administration of doubling concentrations of methacholine to 32 mg.ml-1 methacholine, or until the baseline forced expiratory volume in one second (FEV1) was reduced by 20%; and 2) during incremental cycle ergometry (100 kpm.min-1 each minute) to maximal capacity. 138/175 subjects achieved a 20% reduction in their baseline FEV1; 18 of the 138 were excluded, 2 children and 16 with complicating pulmonary disorders (diffusing capacity of the lung for carbon monoxide (DLCO) and/or total lung capacity (TLC) < 70% predicted). The remaining 120 out of 175 constituted the study population. Dyspnoea following a 20% reduction in the baseline FEV1 (Dys20%) was linearly interpolated, using the rating of dyspnoea and the FEV1 at the two final concentrations of methacholine. In the 120 asthmatic subjects, the mean intensity of dyspnoea was "moderate" (2.9, SD 1.91; Borg 0-10) and the intensity across subjects was not significantly related to baseline FEV1, vital capacity (VC), FEV1/VC, DLCO, TLC and maximal static inspiratory pressure (MIP), alone or in combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Neonatal lupus erythematosus syndrome: late detection of isolated heart block.

Heart block in neonatal lupus erythematosus is typically complete and detected in utero or in the neonatal period. We describe a child diagnosed with incomplete heart block at 9 years of age whose mother was diagnosed with Sjögren's syndrome and anti-Ro(SSA) 2 years after diagnosis of heart block in her child. This is the first case of late detection of incomplete heart block in a child felt to be causally related to the presence of anti-Ro(SSA) in the mother.

Autoantigens↗
PubMed1992

Cutaneous manifestations of the eosinophilia-myalgia syndrome.

We report the cutaneous manifestations of the eosinophilia-myalgia syndrome in 10 patients, with specific reference to their clinical course, histopathological features, and immunogenetic studies. Cutaneous manifestations could be classified into three groups: morphoea-like sclerosis, urticarial and papular lesions, and generalized sclerosis. Despite this polymorphic clinical presentation, the histopathological abnormalities in all cases were strikingly similar, and consisted of superficial and deep perivascular lymphocytic dermal infiltrates, mucin deposition, and fascial inflammation (often in the absence of sclerosis). Immunoperoxidase studies revealed increased numbers of factor XIIIa- and MAC 387-positive cells in the inflammatory infiltrate. Immunogenetic studies demonstrated that 77% (7/9) of patients possessed the HLA-DR3 or HLA-DR4 phenotypes. Mean follow-up of 24 months after discontinuation of L-tryptophan revealed the presence of persistent severe disabling disease in 30% of patients.

Adult↗
PubMed1992

Changes in the cellular profile of induced sputum after allergen-induced asthmatic responses.

Allergen inhalation causes airway inflammation and an increase in histamine airway responsiveness. We have used cell counts in sputum induced by hypertonic saline aerosol to assess airway inflammation before and 32 h after asthmatic responses to allergen. Twelve asthmatic subjects (mean age, 27.4 yr; range, 20-38 yr) had an inhalation test with D. farinae, ragweed pollen, or cat extract. All of them developed an early response with a fall in FEV1, of 24.8% (SD, 6.3%); nine of 12 had a definite late response (fall in FEV1 greater than or equal to 15%), and 10 of 12 had an increase in airway responsiveness to histamine at 32 h (PC20 reduced by greater than twofold). Sputum was induced by hypertonic saline after the histamine test, before and 32 h after the allergen challenge, at the same time of day. The quality of the sample was scored according to visual inspection and inverted microscopy and by salivary contamination. Plugs arising from the lower respiratory tract were selected for further evaluation. Differential cell counts of eosinophils (Eo) and metachromatic cells (MCC) (mast cell and basophils) were obtained from direct smears, blind to the clinical procedures. The mean fall in FEV1 after hypertonic saline was 6.4% (range, zero to 28%). The sputum samples were adequate in 79.5% of attempts. Eo and MCC increased significantly from 3.8 (4.4) to 18.2 (22.8)% (p = 0.01) and from 0.05 (0.17) to 0.25 (0.76)% (p = 0.04), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of an inhaled thromboxane mimetic (U46619) on airway function in human subjects.

Thromboxane A2(TxA2) has been implicated in the pathogenesis of airway hyperresponsiveness. The effects of inhaled TxA2 on human airway function have not been studied because of its short half-life. U46619 is a chemical that mimics the effects of TxA2. The purpose of this study was to evaluate the effects of inhaled U46619 on human airway function and methacholine airway responsiveness. Airway responsiveness to methacholine and U46619 was measured in 19 subjects (13 asthmatic and six normal) and expressed as the provocative concentration causing a 20% fall in FEV1 (PC20). On one day, methacholine alone was inhaled. On a second day, U46619 was inhaled, then 1 h later methacholine was inhaled. On a third day, U46619 was inhaled, then repeated 1 h later. In six subjects, the effects of isotonic saline or a subthreshold concentration of histamine or U46619 were examined on methacholine airway responsiveness. U46619 was 178 times more potent as a bronchoconstrictor than was methacholine. Airway responsiveness to methacholine was correlated to airway responsiveness to U46619 (r = 0.87, p = 0.001). Subthreshold concentrations of U46619, but not of histamine, increased methacholine airway responsiveness. The mean maximal fall in FEV1 after inhaled methacholine was 13.2% (SEM, 3.4%) after saline, 12.4% (SEM, 2.4%) after histamine, and 25.7% (SEM, 2.0%) after U46619 (p = 0.0004). This effect lasted less than 1 h. There was no tachyphylaxis to repeated inhalations of U46619. These results indicate that in human subjects inhaled U46619 is a potent bronchoconstrictor that, when present in the airways, can cause airway hyperresponsiveness to inhaled methacholine in asthmatic subjects.

Aerosols↗
PubMed1992

A multicenter study of overdentures supported by Brånemark implants.

Nine clinical centers participated in a prospective study of overdentures supported by Brånemark implants in the maxilla or mandible. The study initially comprised 133 patients provided with 117 implants placed in the maxilla and 393 implants placed in the mandible. The preliminary results indicate a success rate in the mandible comparable with the reports on fixed prostheses. Conversely, overdenture treatment in the maxilla seems to be less favorable than previous reports of fixed restorations. The differences between the fixed and the present overdentures in the maxilla were mainly based on differences in patient selection and bone quality. A total of 32 implants was mobile and removed and another 29 implants were lost to follow-up because of patient dropout up to the first annual checkup after denture placement. A higher implant failure rate occurred in the maxilla. Mucosal reactions were also more unfavorable around implants placed in the maxilla.

Adult↗
PubMed1992

U1RNP antibody-positive neonatal lupus. A report of two cases with immunogenetic studies.

BACKGROUND: Neonatal lupus erythematosus (NLE) is a distinct subset of lupus characterized by cutaneous findings (50%), cardiac conduction defects (50%), and autoantibodies to Ro (SS-A) antigen. HLA typing studies of Ro (SS-A) antibody-positive mothers of infants with NLE have shown an association with the HLA-DR3 phenotype. We report the clinical and serologic features of two infant-mother pairs who are U1RNP antibody positive and Ro (SS-A) antibody negative. HLA typing is reported on these infants, their mothers, and two additional infant-mother pairs with U1RNP antibody-positive lupus whose clinical features have been reported previously. OBSERVATIONS: Cutaneous findings included malar erythema, annular and polycyclic plaques, and scales that resolved with residual telangiectasia and hyperpigmentation 6 months after birth. Systemic abnormalities, including complete heart block, were absent. HLA typing revealed HLA-DR3 in two of four mothers, HLA-DR4 and HLA-DRw53 in two of four mothers, and either HLA-DQ1 or HLA-DQ3 in four of four mothers. No distinct HLA associations were seen in the three infants examined. CONCLUSIONS: The spectrum of cutaneous disease in U1RNP antibody-positive infants is similar to Ro (SS-A) antibody-positive infants with NLE. Complete heart block was not a feature of U1RNP antibody-positive NLE. HLA typing studies show a more diverse immunogenetic pattern in U1RNP antibody-positive mothers of infants with NLE compared with Ro (SS-A) antibody-positive mothers.

Adult↗
PubMed1992

Neonatal lupus erythematosus syndrome: analysis of C4 allotypes and C4 genes in 18 families.

We examined 18 families with infants who had neonatal lupus erythematosus (NLE) syndrome to determine whether abnormalities in C4 phenotypes and genotypes were an additional risk factor for this syndrome. Fifteen of 18 mothers of infants with NLE (83%) had C4 null allotypes compared with 36% of population controls (p = less than .001). This increased frequency was due mainly to the presence of C4A null allotypes (11/18, 61%). C4 gene abnormalities, i.e., deletion or probable duplication, were present in 100% (16/16) of mothers of infants with NLE. The most common molecular genetic abnormality in mothers of infants with NLE in this study was deletion of C4A genes. Duplication of C4A and C4B loci was also commonly seen. Duplication of C4A genes was detected only in mothers of infants with complete congenital heart block (CCHB), and duplication of C4B was detected only in mothers of infants with dermatitis. No significant increase in C4A or C4B null allotypes or protein deficiencies was noted in mothers of infants with neonatal lupus when compared with anti-Ro(SS-A)-positive mothers delivered of clinically normal infants. Fathers of infants with NLE showed a trend toward increase in C4B null allotypes when compared with population controls (75%, 3/4, p = .06). The two infants with CCHB examined were C4B protein-deficient, in contrast to infants with lupus dermatitis, who had frequent C4B null allotypes but no C4B protein deficiency. C4B null allotypes were not seen in unaffected siblings of infants with NLE and in only 1 of 7 anti-Ro(SS-A)-positive mothers who delivered clinically normal infants. We conclude that inheritance of C4A null allotypes is not predictive of increased risk of neonatal lupus when present in anti-Ro(SS-A)-positive women. Examination of paternal and maternal C4 genes of additional infants with NLE, in particular those with CCHB, and of normal infants born to anti-Ro(SS-A)-positive mothers--and of the normal infants' parents--is required to determine if abnormal C4B genes are a critical factor rendering susceptibility to the NLE syndrome.

Antibodies, Antinuclear↗
PubMed1991

Subacute cutaneous lupus erythematosus-immunogenetic associations.

Thirty-two patients who fulfilled criteria for subacute cutaneous lupus erythematosus (SCLE) were examined for their immunogenetic associations. Our results confirm the previously reported association of HLA-DR3 (15/31 48% P less than 0.01) and also demonstrate an increase in HLA-DR2 (14/31, 45%, P = less than 0.05). These findings indicate there are two distinct immunogenetic (HLA) populations of Ro(SS-A) antibody-positive SCLE patients. The increased frequency of HLA-DR2 and DR3 appears to be associated with expression of the Ro(SS-A) antibody, since no HLA associations were seen in Ro(SS-A)-negative SCLE patients when compared with normal population controls. Furthermore, these data indicate that the distinctive cutaneous lesions of SCLE are not associated with one specific HLA allele, as previously suspected. These findings contrast with the relatively homogeneous immunogenetic background seen in other lupus erythematosus subsets with a high frequency of Ro(SS-A) antibody, i.e., neonatal lupus erythematosus and Sjögren's syndrome/lupus erythematosus overlap (increased frequency of HLA-DR3, DQw2 and DRW52).

Adult↗
PubMed1991

Detection of anti-Ro(SSA) antibodies by gel double diffusion and a 'sandwich' ELISA in systemic and subacute cutaneous lupus erythematosus and Sjögren's syndrome.

A newly described Ro 'sandwich' ELISA was compared to the gel double diffusion technique to detect anti-Ro(SSA) antibodies in Sjögren's syndrome, systemic and subacute cutaneous lupus erythematosus patients. This study demonstrates that the ELISA assay increased the frequency of detection of anti-Ro(SSA) antibodies in these well defined connective tissue disease patients by approximately 5-10% compared to the gel double diffusion anti-Ro(SSA) antibody assay. The study also confirms that some patients make anti-Ro(SSA) antibodies directed solely at unique human Ro(SSA) antigen epitopes. We also detected the existence of a significant Sjögren's syndrome patient population failing to make significant anti-Ro(SSA) antibodies. We conclude from our study that the gel double-diffusion technique employing human spleen extract as a source of the Ro(SSA) antigen is, at present, the most cost-effective test to detect anti-Ro(SSA) antibodies.

Antibodies, Antinuclear↗
PubMed1990

Inhibition of exercise-induced bronchoconstriction by MK-571, a potent leukotriene D4-receptor antagonist.

BACKGROUND: Exercise is a common stimulus of bronchoconstriction in subjects with asthma, who also have bronchoconstriction after inhaling the sulfidopeptide leukotriene D4 (LTD4). The purpose of this study was to investigate the importance of LTD4 as a mediator of exercise-induced bronchoconstriction. METHODS: In a double-blind, randomized, crossover study, 12 subjects with stable asthma were treated intravenously with MK-571 (160 mg), a selective and potent LTD4-receptor antagonist, or placebo, 20 minutes before each of two challenges involving exercise at a level previously demonstrated to cause a fall of at least 20 percent in the forced expiratory volume in one second (FEV1). The two exercise challenges were separated by one week. The results of the challenges were expressed as both the maximal fall in FEV1 after exercise and the time to recovery from bronchoconstriction. RESULTS: Treatment with MK-571 attenuated exercise-induced bronchoconstriction in all the subjects. The mean (+/- SEM) maximal percent decrease in FEV1 after exercise was 25.2 +/- 3.5 percent in the subjects taking placebo and 9.2 +/- 2.5 percent in the subjects taking MK-571 (P less than 0.001). The mean percent inhibition for the entire group was 69.5 percent. The mean time to recovery after exercise was 33.4 +/- 4.0 minutes in the placebo group and 8.4 +/- 2.5 minutes in the MK-571 group (P less than 0.001). CONCLUSIONS: This study demonstrates that pretreatment with a potent and selective LTD4 antagonist markedly attenuates exercise-induced bronchoconstriction, and it suggests that LTD4 is a major mediator of this type of bronchoconstriction.

Asthma, Exercise-Induced↗
PubMed1990

The benefit of dental care to an elderly population assessed using a sociodental measure of oral handicap.

The provision of dental care is based on the assumption that it contributes to quality of life. One hundred elderly people requesting dental care were interviewed and treated. Assessment was made using a sociodental index as well as clinical criteria. The index measured four categories of oral handicap (impairment of function, comfort, self-image and social interaction) prior to treatment and any benefit conferred by the treatment. Seventy-four per cent benefited from treatment. The greatest improvements were in self-image and social interaction. Function was the most difficult category to satisfy. One third of subjects whose oral function was compromised before treatment were still in this state after treatment.

Aged↗
PubMed1990

Barriers to dental care in an elderly population resident in an inner city area.

A sample of 765 elderly people living in London was interviewed and examined. Barriers to dental care stemmed from: elderly people's beliefs that dentures should last a life-time and dental visits are unnecessary for edentulous persons: mobility difficulties; fear; problems with access to NHS care and with access to satisfactory care. The attitudes of general dental practitioners, community dentists and final year dental students towards elderly people were favourable. Sixty per cent of surgeries were on the ground floor, and 46 per cent of premises were unsuitable for wheelchair access. Carers wanted improvement in domiciliary services. The provision of domiciliary care was significantly related to training. There was a paucity of experience in this field amongst dental students. Community dentists recognized a need for retraining before providing care for handicapped elderly people.

Aged↗
PubMed1990

Tachyphylaxis to inhaled methacholine in normal but not asthmatic subjects.

Methacholine inhalation tests measure airway responsiveness in asthmatic and normal subjects. Tachyphylaxis occurs with repeated methacholine inhalations in normal subjects. The purpose of this study was to examine the time course and mechanisms of methacholine tachyphylaxis in normal subjects and to determine whether this occurs in mildly asthmatic subjects. Fifteen normal and nine asthmatic subjects were studied on 2 study days, at least 48 h apart. Each day, two inhalation tests were carried out. On one day, subjects performed two methacholine inhalation tests 3 h later by a methacholine test. Results were expressed as the provocation concentration causing a 20% fall in forced expiratory volume in 1 s (FEV1), (PC20). All normal subjects developed methacholine tachyphylaxis. The mean PC20 increased from 47.3 mg/ml (%SE 1.34) to 115.6 (%SE 1.51) (P less than 0.0001) in a 3-h interval. This increase lasted for greater than or equal to 6 h (P = 0.012). Asthmatic subjects did not develop methacholine tachyphylaxis. Their mean methacholine PC20s were 1.6 mg/ml (%SE 1.4) and 1.5 (%SE 1.4) (P = 0.75) 3 h later. In two other series of experiments, normal subjects were pretreated with the cyclooxygenase inhibitors indomethacin (100 mg/day) or flurbiprofen (150 mg/day) or a placebo for 3 days before two methacholine tests 3 h apart. Both indomethacin and flurbiprofen significantly inhibited the development of methacholine tachyphylaxis. These results confirm that methacholine tachyphylaxis occurs in normal subjects, lasts greater than or equal to 6 h, and may occur through the release of inhibitory prostaglandins. By contrast, methacholine tachyphylaxis does not occur in asthmatic subjects.

Administration, Inhalation↗
PubMed1990

Methacholine airway responsiveness decreases during exercise in asthmatic subjects.

In many asthmatic subjects, bronchoconstriction develops 2 to 5 min after exercise, reaches a maximum at approximately 10 min, and declines over the next 60 min. However, bronchodilation is typically observed during and immediately after exercise. We measured the bronchoconstrictor responses to increasing concentrations of inhaled methacholine at rest and during two levels of exercise in seven asthmatic subjects to determine the protection against bronchoconstriction afforded by exercise. On the first day, an incremental Stage 1 exercise test was performed to determine the work capacity (Wcap) of each subject. On the second, third, and fourth days, methacholine was inhaled at rest or during steady-state exercise at one-third or two-thirds of Wcap. The bronchoconstrictor response to methacholine was significantly reduced during exercise (p less than 0.0001). The concentration of methacholine required to produce a 20% reduction in FEV1 (PC20) increased from 2.80 mg/ml (%SEM, 1.62) at rest to 7.29 mg/ml (%SEM, 1.43) during exercise at one-third Wcap, and to 31.03 mg/ml (%SEM, 1.74) during exercise at two-thirds Wcap (p less than 0.001). This study has demonstrated that there is greater than tenfold protection against bronchoconstriction by methacholine during exercise, and the magnitude of the protection depends on the intensity of exercise performed. The mechanism of this protection is not known, but may have clinical utility.

Adolescent↗
PubMed1989

The immunogenetic relationship between anti-Ro(SS-A)/La(SS-B) antibody positive Sjögren's/lupus erythematosus overlap syndrome and the neonatal lupus syndrome.

We have described previously the clinical features of a unique group of anti-Ro(SS-A) antibody positive Sjogren's patients who have cutaneous features of lupus erythematosus, most commonly subacute cutaneous lupus erythematosus, defined as the Sjogren's/lupus erythematosus overlap syndrome. Three of these patients are also mothers of infants with the neonatal lupus erythematosus syndrome, characterized by cutaneous lesions resembling subacute cutaneous lupus erythematosus or congenital heart block. Patients with Sjogren's/lupus erythematosus overlap syndrome, subacute cutaneous lupus erythematosus, and mothers of infants with the neonatal lupus syndrome characteristically have autoantibodies to Ro(SS-A), and in many cases, La(SS-B) antigens. The present study was designed to test the hypothesis that anti-Ro(SS-A)/La(SS-B) positive Sjogren's/lupus overlap patients and mothers of infants with neonatal lupus erythematosus syndrome are immunogenetically homogenous and closely related. We report a strong association with HLA-B8, DR3, DQw2, and DRw52 phenotypes and the HLA-B8, DR3, DQw2, DRw52 extended haplotype in both patient cohorts. Furthermore, we describe disease associations with HLA-DR3/DRw6 heterozygotes in both patient groups. These data demonstrate that anti-Ro(SS-A)/La(SS-B) positive Sjogren's/lupus overlap patients and neonatal lupus syndrome mothers are immunogenetically closely related to each other and appear to be more closely related to both primary Sjogren's syndrome and subacute lupus erythematosus, than to classical systemic lupus erythematosus.

Antibodies, Antinuclear↗
PubMed1989

Tooth positions in the natural and complete artificial dentitions, with special reference to the incisor teeth: an interactive on-line computer analysis.

A comparison of tooth positions and soft tissue profiles was made between samples of edentulous patients recently provided with new complete dentures, and dentate subjects. The dentures were marked with lead foil on the most prominent incisor teeth and labial surfaces of the flanges. Lateral skull radiographs were made with the jaws in centric relation. The dentate subjects were recorded with the teeth held in centric occlusion. Discrete soft and hard tissue landmarks were identified and recorded using an interactive on-line computer system, enabling linear and angular measurements to be made. A mathematical comparison was produced employing a series of independent t-tests. Composite computer tracings were also produced. Important differences were found between the two groups, in which the influence of the upper lip length, mandibular resorption, and selected overbite were identified as factors determining artificial tooth position.

Adult↗