Biomedical subjects

T To

Publications and source records attributed to T To.

At least 73 records · Page 4Linked to original sources

PubMed1992

Pesticide concentrations in Arkansas breast milk.

During an episode of pesticide dairy product contamination in Arkansas in 1986, breast milk samples from 942 women were analyzed for concentrations of chlorinated pesticides. The pesticides found most frequently in quantifiable concentrations were p,p'-DDE (100%), oxychlordane (84%), trans-nonachlor (77%), heptachlor epoxide (74%) and beta-HCH, an isomer of lindane (27%). The pesticides present in highest mean concentrations of all samples analyzed (reported as ppm in milk fat) were p,p'-DDE (0.952 ppm), trans-nonachlor (0.062 ppm), oxychlordane (0.051 ppm), heptachlor epoxide (0.045 ppm), p,p'-DDT (0.039 ppm), and beta-HCH (0.032 ppm). These concentrations are lower than previous reports from similar regions of the US. However, continued persistence in human breast milk is of concern due to potential adverse health effects from these chemicals.

Adolescent↗

PubMed1991

A study of acne treatments as risk factors for skin cancer of the head and neck.

A retrospective questionnaire was conducted as to the risk factors for facial skin cancer with emphasis on acne and past treatments for acne, in particular use of benzoyl peroxide preparations. The response rate was 90.9% for 964 cases and 79.9% for 3856 controls. There was no association between acne and the use of any acne medication for the risk of facial skin cancer. Cases of skin cancer were significantly more likely to have used phototherapy or sunbeds than the controls (P = 0.024), and more likely to have had radiotherapy prior to diagnosis (P = 0.001). The major risk factors as determined by generalized linear interactive modelling were family history of skin cancer (odds ratio 2.68; 95% confidence interval 2.15, 3.34), light skin (1.54; 1.25, 1.89), sunburning easily (1.43; 1.16, 1.76) and Irish, Scottish, Scandinavian or German mothers (1.33; 1.11, 1.59).

Acne Vulgaris↗

PubMed1991

Interactions of tumor necrosis factor and granulocytes with pulmonary vascular resistance.

We studied the effects of endotoxin and tumor necrosis factor (TNF-alpha) on hypoxic pulmonary vasoconstriction (HPV) in 12 isolated perfused canine lung lobes. Group 1 lobes were perfused with whole blood, and group 2 lobes were perfused with granulocyte-depleted blood. All lobes were sequentially ventilated with control (35% O2) and hypoxic (3% O2) gas mixtures before and after receiving TNF-alpha. After TNF-alpha, group 2 lost HPV but group 1 retained HPV. After TNF-alpha, total pulmonary vascular resistance decreased in group 2 from 0.085 +/- 0.013 to 0.049 +/- 0.016 cmH2O.ml-1.min (P less than 0.05). We conclude that TNF-alpha acts as a pulmonary vascular vasodilator. In lobes perfused with whole blood, HPV is paradoxically preserved. We speculate that in the presence of cells rich in TNF-alpha receptors, i.e., granulocytes, the circulating levels of TNF-alpha are depressed and full expression of its vascular effects is blunted.

Animals↗

PubMed1991

Clinical use of immunoperoxidase markers in excluding ectopic gestation.

Ectopic pregnancy is suspected when a pregnancy test is positive and an Arias-Stella phenomenon with decidua is seen on endometrial curettings in the absence of chorionic villi and trophoblast. We performed immunoperoxidase stains for beta-hCG, hPL, placental alkaline phosphatase, and keratin (AE1/AE3) on endometrial curettings of 72 patients with first-trimester bleeding in whom ectopic pregnancy was suspected based on routine hematoxylin and eosin (H&E) stain. Negative immunoperoxidase stains correlated with a retrospective patient chart review identified only ten patients with extrauterine pregnancy, a prevalence of 14%. The sensitivity of hCG, hPL, placental alkaline phosphatase, and keratin markers in detecting trophoblastic cells in the curettings was 42, 48, 24, and 69%, respectively. Each marker had a specificity of 100%. When both keratin and hPL were used, the sensitivity improved to 73%; however, there was no advantage in using three or more markers. We conclude that 73% of patients suspected to have ectopic pregnancy would be spared additional diagnostic techniques when immunoperoxidase markers for keratin and hPL are used on endometrial curettings without trophoblast on routine H&E stain. The procedure requires only 3 hours of laboratory time.

Decidua↗

PubMed1991

Relative roles of prostaglandins and leukotrienes in canine hypoxic pulmonary vasoconstriction.

We indirectly examined the role of prostaglandins and leukotrienes in modulation of hypoxic pulmonary vasoconstriction. We used a cyclo-oxygenase inhibitor (indomethacin) and a lipoxygenase inhibitor (diethylcarbamazine) in an in-situ canine lung lobe preparation. We measured total resistance in two control groups ventilated with either 35% O2 or 3% O2 (groups CC and HC respectively). Two additional groups treated with indomethacin (groups CI and HI), and two groups treated with the combination of indomethacin and diethylcarbamazine (groups CID and HID), were also ventilated with either 35% O2 or 3% O2 respectively. Total resistance was significantly greater in hypoxic groups compared with their respective control oxygen groups. Total resistance was greatest in group HI (0.288 +/- 0.103 cm H2O.ml-1 min-1), intermediate in group HID (0.153 +/- 0.016 cm H2O.ml-1 min-1) and lowest in group HC (0.066 +/- 0.017 cm H2O.ml-1 min-1). We concluded that cyclo-oxygenase blockade augments hypoxic pulmonary vasoconstriction by decreasing production of a vasodilating prostaglandin. Hypoxia also increases production of a vasoconstricting leukotriene in the presence of cyclo-oxygenase blockade with indomethacin.

Analysis of Variance↗

PubMed1990

Changes in breast self-examination behavior achieved by 89,835 participants in the Canadian National Breast Screening Study.

Breast self-examination (BSE) behavior was analyzed in 89,835 participants in the National Breast Screening Study (NBSS) of whom 64,619 were eligible for annual rescreening and 25,216 were followed by mail after a single screen exam. Among those eligible for rescreening, BSE competence scores based on seven BSE criteria significantly improved over time and correlated directly with reported BSE frequencies. Among all participants, the proportion reporting BSE frequencies of greater than or equal to 12/year increased over time from approximately 20% on entry to 50% to 64% at final screen. Similarly, reports of zero frequency diminished from 50% to 10% to 15%. Variables such as educational status, age (fifth versus sixth decades), eligibility for mammography, smoking history, and ethnic origin had negligible or no influence on BSE competence. However, women with first-degree relatives with breast cancer had significantly higher BSE scores. NBSS experience suggests that most women who enter screening programs will upgrade their BSE skills if subjected to brief episodes of repeated BSE instruction.

Adult↗

PubMed1990

Women's attitudes to screening after participation in the National Breast Screening Study. A questionnaire survey.

A self-administered questionnaire study exploring women's attitudes to breast screening after participation in the Canadian National Breast Screening Study (NBSS) achieved an 82% response rate. Of active respondents (AR) attending two to five screening examinations, 1582 had received annual mammography (MA) and physical examination (PE) of the breasts and 548 received annual PE alone. Of 139 dropouts after the first screening, 105 received MA and PE and 34 received PE alone. Dropout respondents (DR) were significantly less likely than AR to report receiving very prompt (46% versus 66%), very courteous (73% versus 92%), or very competent examinations (74% versus 95%). Although 35% of those allocated to PE expressed disappointment with PE allocation compared with 9% of those allocated to MA, fewer of those allocated PE were prepared to accept MA in the future than those allocated MA (59% versus 73%). Of those who had MA, 36% reported moderate and 9% extreme discomfort from mammography. Almost half of each subgroup--MA allocations, PE allocations, and DR--preferred mammography every 2 to 3 years and 30% preferred mammography restricted to diagnostic purposes. Only 5% of AR reported anxiety after screening. National Breast Screening Study participation was a positive experience for 93%. An intention to do breast self-examination (BSE) was reported by 89% of AR and 79% of DR. Forgetfulness was a major impediment to BSE. Disincentives for screening were excessive distance to center, painful mammography, fear of radiation, lack of time, and preference for own physician. Convenient location, punctual appointments, and courteous and supportive staff should enhance screening compliance.

Adult↗

PubMed1990

The effects of halothane in hypoxic pulmonary vasoconstriction.

Human and animal experiments have not consistently shown halothane to inhibit hypoxic pulmonary vasoconstriction (HPV). The authors used a canine lung lobe perfused in situ to more precisely characterize the effects of halothane on HPV. The pulmonary vasculature can be divided into inflow, middle, and outflow segments by sequentially occluding the lobar inflow and outflow of blood. The lobes were ventilated with four different gas mixtures (normoxia, hypoxia, normoxia/halothane, hypoxia/halothane) and measured inflow, outflow, and middle segment (Rm) resistances using this stop-flow technique. All values are shown as means +/- standard deviation. The authors found that hypoxia increased Rm from normoxia values of .006 +/- .005 cmH2O.ml-1.min-1 to .025 +/- .008 cmH2O.ml-1.min-1 (P less than 0.05). During hypoxia/halothane Rm returned to .005 +/- .004 cmH2O.ml-1.min-1. The relationship between pressure and flow (P-Q) for the lobes for each gas mixture was also determined. The slopes of the P-Q lines by linear regression were all similar. The zero-flow pressure intercepts of the P-Q lines for normoxia (3.2 +/- .9 cmH2O) and hypoxia (4.4 +/- 1.1 cmH2O) were significantly decreased after the administration of halothane (1.7 +/- 1.0 cmH2O and 2.6 +/- 1.0 cmH2O, respectively). Since the zero-flow intercept likely reflects the tone at alveolar vessel level, the authors conclude that halothane inhibits HPV by decreasing the tone in the middle vascular segment.

Animals↗

PubMed1990

Herpes labialis in parturients receiving epidural morphine following cesarean section.

A significant association exists between the use of epidural morphine (EM), reactivation of herpes labialis (HL) commonly known as coldsores, and pruritus in the obstetric population. A randomized prospective study was designed to eliminate previously identified confounding variables. Immediately following delivery, parturients having undergone cesarean section with epidural anesthesia with carbonated lidocaine (Xylocaine CO2, Astra, Mississauga, Ontario, Canada) with 1:200,000 epinephrine were sequentially randomized to receive either EM or im opioids for postoperative analgesia. One blood sample was collected for viral serology and two mouthwashes (day 0 and 2) were collected to determine oral viral shedding. The patients were observed daily for 5 days. Coldsores were cultured for herpes simplex virus (HSV). Of 187 patients, 96 received EM and 91 im opioids; herpes labialis occurred in 14 of 96 (14.6%) of the former but in 0 of 91 of the latter (P = 0.0004). All 14 experienced facial pruritus. The two groups were at equal risk for reactivation (seropositivity 64.6% and 62.6%, respectively). Analysis of data for those with positive HSV serology reveals 14 of 62 (22.5%) had EM and herpes labialis compared with 0 of 57 in the im group (P less than 0.0001). The incidence of oral viral shedding was low. Surgical stress, the local anesthetic solution, and epinephrine addition to the local anesthetic were eliminated as confounders. Stepwise logistic regression analysis revealed that EM and a history of herpes labialis in these patients were predictive for reactivating oral HSV.

Adult↗

PubMed1990

Canadian National Breast Screening Study: assessment of technical quality by external review.

Mammograms from the Canadian National Breast Screening Study (NBSS) were reviewed by three external experts to provide an objective evaluation of their technical quality, to establish a model for auditing mammograms in a screening program, and to assess whether NBSS mammograms improved over time. The sample reviewed included 10 randomly chosen mammograms from each of 15 screening centers for each calendar year of their operation between 1980 and 1987. All 830 mammograms were reviewed on two consecutive days in randomized sequence by each reader, and rated 0-3 for each of four criteria including positioning and image quality, with a total possible score of 0-12. Although the mammograms were not in temporal sequence when reviewed, the scores assigned by each reader were significantly higher for mammograms dating from later years. Subjects' ages at entry (40-49 vs 50-59 years) did not affect the score. The largest increase in scores was associated with a 1985 protocol change in which mediolateral oblique positioning replaced straight mediolateral positioning. This study reinforces the importance of monitoring technical quality in screening programs and establishes that the NBSS benefited from technical improvements during its operation. A retrospective review of NBSS mammography by three external reviewers confirmed that technical quality improved from 1980 to 1987. This improvement was associated with improved technology (film, processing, and units) and with the quality assurance programs operating during the NBSS, which identified problems and offered remedies.

Adult↗

PubMed1990

Efficacy of chlorhexidine and sanguinarine mouthrinses on selected salivary microflora.

The antibacterial effects of chlorhexidine and sanguinarine on selected salivary microflora were evaluated in 15 healthy young adults. The experiment was performed in a cross-over manner enabling both mouthrinses and the saline control to be tested on all 15 subjects for periods of one week separated by three week intervals. The total bacterial count and selected bacterial genera were followed in saliva samples taken just before the first rinse, and on three occasions after the last rinse. Statistically significant reductions in the salivary levels of S. mutans and S. salivarius were obtained with chlorhexidine but not with sanguinarine, and rinsing twice a day with sanguinarine, according to the manufacturer's instructions, did not significantly reduce the total bacterial count. Additional well controlled, longer-term studies are required before any firm conclusions can be drawn regarding the effect of sanguinarine on salivary microorganisms.

Adult↗

PubMed1989

Incidence of infantile hypertrophic pyloric stenosis in Saskatchewan, 1970-85.

We reviewed the incidence rates of infantile hypertrophic pyloric stenosis (IHPS) and pylorospasm in Saskatchewan from 1970 to 1985 and found a marked decrease in the rates after 1976. As expected, there was a preponderance of males among those with IHPS and among those with pylorospasm discharged from hospital between 1 and 3 months of age. No seasonal pattern was observed. We believe that the decrease in incidence rates was related to environmental influences, such as changes in the methods of feeding observed since 1977.

Female↗

PubMed1989

Infantile hypertrophic pyloric stenosis: a study of feeding practices and other possible causes.

We carried out a case-control study of the hospital charts of 91 infants with infantile hypertrophic pyloric stenosis (IHPS) to determine the feeding practices at the time of discharge from the neonatal nursery. We excluded infants whose feeding might have been influenced by confounding factors. The infants were matched with controls for gestational age. The mean birth weight of the IHPS group was 3501 g and of the control group 3543 g. The male:female ratio for the IHPS group was 5.5. The odds ratio of male predominance was 4. We found that bottle-feeding was 2.9 times more prevalent among the infants with IHPS than among the control subjects. We speculate that the recently observed decrease in the incidence of IHPS is due to the decline in bottle-feeding.

Birth Weight↗

PubMed1989

The glaucoma suspect: differentiation of the future glaucoma eye from the non-glaucomatous suspect eye. 2. Visual field decay.

Visual-field areas to a I2e stimulus were measured planimetrically using an X-Y digitizer and a computer program. Sampling of normal subjects and patients suspected of having glaucoma was done at two points in time. Calculations of eye-wall stress were done using ultrasonic data and intra-ocular pressure (IOP) measurements from patient records. For those suspected of having glaucoma who developed chronic open-angle glaucoma (COAG), the time of transition was the second point in time. The visual field area was regressed against patient age at the two points in time. No difference in the regression slopes was found for the normal subjects and unchanged patients. The patients who did develop glaucoma were significantly different. The mean annual rate of visual-field change (rate of decay) was calculated and found to be 28.5 mm2/year for the normals, 153.5 mm2/year for the suspects, and 376.4 mm2/year for those patients who developed glaucoma. The rate of visual-field decay only correlated with patient age (P = 0.03) and eye-wall stress (P less than 0.01) in the patients who developed glaucoma.

Age Factors↗

PubMed1989

Risk factors for basal cell carcinoma.

Completed questionnaires regarding suspected risk factors for basal cell carcinoma (BCC) were completed by 538 basal cell carcinoma patients and 738 age-, sex-, and location-matched controls in Saskatchewan. Significant risk factors were identified using chi2 analyses. Relative risks were subsequently computed. The following relative risks were identified: occupation of farming, 1.29; prominent freckles in childhood, 1.23; family history of skin cancer, 1.22; sunburn, 1.19; Irish, Scottish, Welsh mother, 1.19; light skin color, 1.18; red/blond hair color, 1.16; and working outdoors more than 3 hours/day in winter, 1.13: The average age of cases of BCC with a family history of skin cancer was significantly lower than cases of BCC with no family history of skin cancer (63.86 vs. 67.02 years, p = 0.018). No association was noted between BCC and psoriasis.

Adult↗

PubMed1989

Ethnic differences in the prevalence of pulmonary airflow obstruction among grain workers.

World Health Organization data suggest that British males over 45 have a higher death rate from chronic bronchitis, emphysema, and asthma combined than do other Europeans. Although widely supposed that this is due to particularly unfavorable environmental factors in the British Isles, as well as a higher rate of tobacco consumption, ethnicity itself may be a significant factor in determining risk of obstructive airways disease. To test this hypothesis, we have analyzed the prevalence of airflow obstruction (100 x FEV1:FVC less than 68% and FEV1 less than 84 percent predicted) in Saskatchewan grain workers of British, German, and Eastern European ancestry using the Mantel-Haenszel odds ratio (OMH) and stepwise logistic regression. We found that the British grain workers had a significantly greater prevalence of airflow obstruction (OMH = 3.2; p less than 0.01) than the Eastern Europeans. We also found that ethnic origin made a significant contribution to the estimation of risk of airflow obstruction among grain workers independent of the effects of age and smoking.

Adolescent↗

PubMed1989

The outcome of chemoprophylaxis on tuberculosis prevention in the Canadian Plains Indian.

A 1986 audit of self-administered anti-tuberculous prophylaxis (SAP) revealed a compliance rate of 25% at six weeks, 8% at 16 weeks, and 5% at 52 weeks. A short affordable program of daily observed prophylaxis (DOP) and education was developed to improve the compliance rate. The sustaining influence of a six week intervention on one year of prophylaxis was determined. Forty-two of 114 (37%) eligible patients began chemoprophylaxis and were randomly assigned to two groups - 21 in Group 1 with DOP and education, and 21 in Group 2 with SAP and education. After six weeks, Group 1 compliance was greater than 1986 compliance (p less than 0.001) and greater than Group 2 compliance (p less than 0.05), and Group 2 compliance was greater than 1986 compliance (p less than 0.01). At 16 weeks, 10 weeks after DOP and education were discontinued, the compliance of the three groups was not different. Since 63% of persons who represent potential future tuberculosis were lost in the evaluation process before starting preventive treatment, and 5% of those who began preventive treatment completed treatment, only 2% of potential future tuberculosis was prevented. DOP and education significantly improved compliance but the improvements were not sustained after DOP and education were discontinued.

Adolescent↗

PubMed1988

Respiratory symptoms and alterations in pulmonary function tests in swine producers in Saskatchewan: results of a survey of farmers.

To determine whether farmers who produced swine in animal confinement chambers in Saskatchewan were at increased risk of developing respiratory dysfunction, we carried out a respiratory health questionnaire and spirometric pulmonary function test measurements, including forced expired volume in 1 second (FEV1), forced vital capacity (FVC), and the ratio of FEV1 to FVC (FEV1/FVC x 100), on 504 farmers who indicated that they raised swine, and 448 rural-dwelling nonfarming control subjects. Swine producers had lower values for FVC and FEV1 than did the control subjects. However, FEV1/FVC x 100 was somewhat higher in the swine producers. The reduction in FEV1 with retained FEV1/FVC ratio is suggestive of restrictive disease. However, the fact that the FEV1/FVC ratio is only modestly higher in swine producers than in control subjects suggests that there may be a mixed restrictive/obstructive condition in these workers.

Adult↗