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Biomedical subjects

S Gunn

Publications and source records attributed to S Gunn.

14 recordsLinked to original sources
PubMed2006

O3 impacts on plant development: a meta-analysis of root/shoot allocation and growth.

The mechanism of O3 action on plants remains poorly characterized. Symptoms include visible lesions on the leaf surface, reduced growth and a hypothesized reduction in allocation of carbohydrate to roots. The generality of this latter phenomenon has not been demonstrated. Here, a meta-analysis is performed of all available experimental data, to test the hypotheses that O3 exposure of the shoot inhibits biomass allocation below ground (the root/shoot allometric coefficient, k) and inhibits whole-plant growth rate [relative growth rate (RGR)]. Both k and RGR were significantly reduced by O3 (5.6 and 8.2%, respectively). Variability in k was greater than in RGR, and both exhibited some positive as well as mostly negative responses. The effects on k were distinct from the effects on RGR. In some cases, k was reduced while RGR was unaffected. Slow-growing plants (small RGR) exhibited the largest declines in k. These observations may have mechanistic implications regarding O3 phytotoxicity. There were no effects of type of exposure chamber on sensitivity to O3. The analyses indicate that the O3 inhibition of allocation to roots is real and general, but variable. Further experiments are needed for under-represented plant groups, to characterize exceptions to this generalization and to evaluate O3--environment interactions.

Environmental Exposure↗
PubMed2000

The relationship of inflammation in the papanicolaou smear to Chlamydia trachomatis infection in a high-risk population.

Chlamydia trachomatis is a significant etiologic agent responsible for pelvic inflammatory disease leading to tubal infertility. A screening test aimed at identifying women at risk for Chlamydia trachomatis would be of great utility. The Papanicolaou smear is the most widely used screening test in the world. The association of inflammatory cells in the Papanicolaou smear to Chlamydia infection is controversial. We retrospectively examined the Papanicolaou smears of 80 Chlamydia-negative patients with 80 age-matched Chlamydia-positive patients in a high-risk population to see if a significant difference in inflammation was noted between the two groups. We found a statistically significant difference in inflammation scores between the Chlamydia-positive and Chlamydia-negative groups, evidenced by a sensitivity of 83% and a positive predictive value of 65% when using inflammation on Papanicolaou smears as a marker for Chlamydia infection. Grading of inflammation in the Papanicolaou smear can be of potential use in defining patients at highest risk for Chlamydia in a group considered to be at high risk based on sexual history.

Adult↗
PubMed1998

Results of screening 1.9 million Texas newborns for 21-hydroxylase-deficient congenital adrenal hyperplasia.

OBJECTIVE: To assess results of newborn screening for 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) in Texas over 6 years of screening 1.9 million infants. METHODS: In 1989, CAH was incorporated into the ongoing Texas Newborn Screening Program, which requires two screens on each newborn. 17-Hydroxyprogesterone was assayed, without extraction, by radioimmunoassay of blood collected from heel sticks onto filter paper collection cards. Infants with elevated levels of 17-hydroxyprogesterone were referred for evaluation, and those considered to have CAH were studied with respect to disease characteristics. Data were collected by pediatric endocrinologists using standardized forms that included type of CAH, results of laboratory tests, treatment regimen, disease symptoms and signs, and, for girls, degree of genital virilization. RESULTS: The incidence of classic CAH in Texas is 1:16 008, with a ratio of salt-wasting to simple-virilizing of 2.7:1. A majority of infants detected were undiagnosed until screened, despite signs of salt-wasting or ambiguous genitalia. It was difficult to differentiate salt-wasting from simple-virilizing CAH in infants who were identified before the onset of adrenal insufficiency or electrolyte abnormalities. A substantial number of infants with nonclassic (NC) CAH also were detected. Not all infants were detected on the initial screen; 14% of infants with classic CAH and 87% with NC CAH were detected on the second routine screening test. CONCLUSIONS: Our findings confirm the benefits of newborn screening for CAH and the importance of a second screening test, and suggest that programs for newborn CAH screening must consider complex issues in diagnosis and treatment. These results also confirm that CAH is a continuum of disorders, rather than a disorder with discrete subtypes. In addition, the difficulties in differentiating CAH subtypes in newborns, and thus deciding appropriate treatment, and the high incidence of NC CAH suggest that standard diagnostic criteria and treatment regimens for CAH may need modification. Where screening exists, physicians will encounter more cases of CAH than in the past.

17-alpha-Hydroxyprogesterone↗
PubMed1996

Long-term impact of clozapine and psychosocial treatment on psychiatric symptoms and cognitive functioning.

OBJECTIVE: The long-term effects of a combination of clozapine and psychosocial treatment were evaluated in a sample of treatment-refractory state hospital patients with schizophrenia. METHODS: A repeated-measure design was used. Thirty-one patients with schizophrenia received both clozapine and an enhanced psychosocial treatment program. Data were collected at baseline and at one-year, two-year, and three-year follow-ups. Psychiatric symptoms, cognitive functioning, dyskinetic movements, and discharge rate were evaluated. RESULTS: Significant reductions in psychiatric symptoms and improvement in cognitive functioning were found. Differences in the pattern of reductions in positive and negative symptoms over the course of the study were noted. The majority of subjects improved sufficiently to be discharged. CONCLUSIONS: Clozapine, when combined with psychosocial treatment, is effective for treatment of patients with schizophrenia who are not responsive to other medications.

Adult↗
PubMed1995

Effect of polyol gums on dental plaque in orthodontic patients.

Sixty 11- to 15-year-old children wearing fixed orthodontic appliances were given chewing gums containing polyol for daily use after meals and snacks, to study whether the chewing of gums that contained slowly fermentable polyols (xylitol and sorbitol) affects the amount of dental plaque and the number of mutans streptococci present in plaque and saliva. The 60 subjects were randomly divided into four groups, each of which was provided with a supply of 1.35 gm pellet-shaped gums for a period of 1 month, as follows: (1) xylitol; (2) sorbitol; (3) xylitol-sorbitol mixture I (3:2); and (4) xylitol-sorbitol mixture II (4:1). In each group, two pellets with a total initial gum mass of 2.7 gm (maximum polyol dose per day: 10.5 gm), were used six times a day. The fresh and dry weight of dental plaque, collected at baseline and 28 days later from incisors, canines, and premolars from the area between gingival margin and the bracket, reduced in all groups, but most significantly (by 43% to 47%) in children receiving xylitol gum. The plaque and saliva levels of mutans streptococci did not change in the sorbitol group, but was significantly (in most cases) reduced by 13% to 33% in groups that received gum containing xylitol. Provided that the quantity of dental plaque and the plaque and salivary levels of mutans streptococci can be regarded as risk factors in dental caries, these results suggest that regular use of polyol gum--and especially gum that contains xylitol as the predominant sweetener--can reduce the caries risk in young patients wearing fixed orthodontic appliances.

Adolescent↗
PubMed1990

Multigenic basis for type I diabetes. Association of HRAS1 polymorphism with HLA-DR3, DQw2/DR4, DQw8.

We analyzed extended haplotypes composed of DNA loci on the short arm of chromosome 11 for segregation with insulin-dependent (type I) diabetes mellitus. The markers for these loci are tyrosine hydroxylase, insulin, and c-Ha-ras-1 proto-oncogene (HRAS1). We report, in a study of 27 families, that a specific haplotype (H), containing a 3-kilobase (kb) HRAS1-Taq I DNA polymorphism, segregated differentially in diabetic and nondiabetic siblings (P = 0.005). A parallel population study showed that the 3-kb HRAS1-Taq I polymorphism is increased in frequency in type I patients having two strong HLA-susceptibility haplotypes compared with other type I patients or healthy control blood donors (P less than 0.010 and P less than 0.025, respectively). The polymorphic variable, enhancer, and promoter regions flanking the human insulin gene on the H haplotype were not associated with type I diabetes. These results indicate that the HRAS1 locus or genes in linkage disequilibrium with this locus are involved in the pathogenesis of HLA-DR3/4 type I diabetes mellitus.

Base Sequence↗
PubMed1989

Primary association of HLA-DQw8 with type I diabetes in DR4 patients.

DNA from 164 Caucasian type I (insulin-dependent) diabetic patients and 200 Caucasian nondiabetic control blood donors were analyzed by the polymerase chain reaction technique for HLA-DR4 and the associated Dw and DQB subtypes of DR4. The DQw8 subtype of HLA-DR4 was associated with type I diabetes in all DR4 subgroups (DR4/3 and DR4/non-3). Dw subtypes of DR4 other than DW10 did not confer additional association with type I diabetes. Thus, the DQ region appears to provide the primary major histocompatibility association with type I diabetes in most DR4 patients.

Adult↗
PubMed1988

Oligonucleotide probes for HLA-DQA and DQB genes define susceptibility to type 1 (insulin-dependent) diabetes mellitus.

We have typed 27 Caucasoid families for DNA restriction fragment length polymorphisms and specific sequences using HLA class II specific cDNA, genomic and oligonucleotide probes. DNA haplotypes were identified by restriction fragment length polymorphism analysis that correlated with previously serologically-defined extended major histocompatibility haplotypes. These DNA haplotypes sort into positive, neutral or negative associations with Type 1 (insulin-dependent) diabetes mellitus. The DNA susceptibility haplotypes are even more simply and specifically defined by oligonucleotide probes for sequences of DQA and DQB genes. Our oligonucleotide probes define variabilities in nucleotide sequences coding for amino acid residues 26, 37 and 38 in the DQ beta-chain. Probes defining DQA sequences are also important for defining susceptibility since certain DQA genes appear to modify DQB susceptibility by conferring resistance. Thus, major histocompatibility conferred susceptibility to diabetes cannot be adequately explained by an amino acid change at a single position in the DQ beta-chain. These probes allow the direct identification of major histocompatibility susceptibility genes in Type 1 diabetes without the necessity of determining full haplotypes.

Blotting, Southern↗
PubMed1986

Effect of protein ingestion on urinary dopamine excretion. Evidence for the functional importance of renal decarboxylation of circulating 3,4-dihydroxyphenylalanine in man.

Since dietary protein increases urinary dopamine (DA) excretion in animals, this study was undertaken to assess the role of DA production in the acute changes in renal function following protein ingestion in man. Excretion of DA, sodium, potassium, water, solute, and creatinine were measured in six normal men in 30-min intervals over 5 h after oral ingestion of protein and/or carbidopa, an inhibitor of DA formation from 3,4-dihydroxyphenylalanine (DOPA). Overall, protein increased urinary DA 50% (P = 0.031) while carbidopa reduced it 70% (P less than 0.0001), although suppression of DA excretion by carbidopa was not uniform over the 5 h of observation. Carbidopa doubled the level of DOPA in venous plasma and greatly magnified the DOPA response to protein. Inhibition of decarboxylase activity reduced excretion of sodium, potassium, solute and water after protein ingestion. These results indicate that extraneuronal DOPA decarboxylation in kidney contributes to acute protein-induced changes in renal function in man and suggest a general role for the decarboxylation of circulating DOPA in the expression of dopaminergic effects on the kidney in vivo.

Adult↗
PubMedDate not supplied

Implementing a comprehensive child restraint program in a pediatric hospital: an effective model.

Motor vehicle crashes remain a leading cause of death and injury to young children. Appropriate child safety seats and child safety restraints can provide life-saving protection to children riding in motor vehicles. Many children, however, travel unrestrained or improperly restrained. Consideration of appropriate child safety restraint systems for children is an important aspect of discharge planning and can provide families with the means to prevent unintentional injuries and deaths resulting from motor vehicle crashes.

Child↗