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Biomedical subjects

T To

Publications and source records attributed to T To.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1987

The significance of the tuberculin skin test in elderly persons.

Study of 49,467 persons over age 50 in Arkansas nursing homes afforded insight into the significance of the tuberculin skin test in the elderly. Whereas only 15% to 20% of persons showed a significant (10 mm or more) reaction to tuberculin on admission, 2% to 3% of these developed tuberculosis. Persons having no reactions comprised two subsets: a small group who died at an increased rate and were probably anergic, and a larger group who survived as well as persons who had reactions. Minor increases in reaction size with repeated testing appeared to be due to immunologic recall. However, conversions of 12 mm or more from a documented negative result indicated spread of infection. When not treated preventively, 7.6% (women) to 12.7% (men) of definite converters developed tuberculosis. The increase in number of persons showing positive reactions after entry may have been due to rapid demise of the anergic subset, improvement in nutrition of survivors, or unsuspected spread of tuberculous infection.

Aged↗
PubMed1987

Benefit-risk considerations in preventive treatment for tuberculosis in elderly persons.

Of 2135 elderly residents of nursing homes in Arkansas (mean age, 79.4 years) who have been treated with isoniazid for prevention of tuberculosis, data from 1935 were suitable for analysis. About 12 months of therapy was successfully completed in 1600 persons. Therapy could not be completed in 84 persons (4.4%) because of incipient hepatic toxicity and in 116 (6.0%) because of other types of drug intolerance. Although 135 persons (7.0%) died during the course of therapy, no evidence was found that isoniazid contributed to any death. The ratio of benefit (reduction of risk for tuberculosis) to risk (for nonfatal isoniazid-related hepatitis) was clearly favorable in persons who had definite conversions (1.6 for women, 3.4 for men) but less so for persons who had tuberculin reactions of unknown duration and for persons with minor increases in size of tuberculin reaction (less than 12 mm increase from an initially negative reaction).

Aged↗
PubMed1986

Carcinoma in situ of the vulva. A clinicopathologic study of 50 cases.

The authors reviewed 50 cases of carcinoma in situ of the vulva treated at the University of Texas Medical Branch, Galveston, from 1975 to 1984. Sixty-two percent of the patients were premenopausal. The most frequent complaint was vulvar itching. Twenty-six percent of the patients were asymptomatic. Recurrences were frequent (25%) and were associated with multifocal lesions, involved surgical margins and the bowenoid histologic type. Superficially invasive carcinoma was detected in 8% of patients, mostly postmenopausal women with simplex histologic types. Immunohistochemical studies failed to detect papillomavirus- or herpesvirus-associated antigens in any of the cases. Follow-up of 48 patients from six months to ten years revealed no mortality from invasive cancer.

Adult↗
PubMed1984

Baseline characteristics of patients in the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry.

The efficacy of PTCA was evaluated in several subgroups of patients. Of special clinical interest were the comparisons between subgroups of patients with multivessel disease vs 1-vessel disease, unstable angina vs stable angina, older age vs younger age, and female sex vs male sex. As a prerequisite for such comparisons, baseline characteristics of patients in the subgroups were examined. Compared with the subgroup with 1-vessel CAD, the subgroup with multivessel CAD had more elderly patients (age 65 years and older) and more of these patients had previous MI or CABG. PTCA was more often unsuccessful in patients with multivessel CAD because of inability to pass the catheter across the lesion. The subgroup of women tended to be older than men, and more women had severe and unstable angina, although fewer had multivessel CAD, previous MI or previous CABG. The PTCA success rate was 5% lower in women because of a greater frequency of inability to pass the lesion. Compared with younger patients, older patients had a higher prevalence of severe angina, multivessel CAD and lesions with larger diameters. The older patients had a 5% lower PTCA success rate, once again because of a greater frequency of inability to pass the lesion. The learning experience with PTCA was measured by the overall success rate as well as by the rate of ability to pass the lesion and the rate of dilating it once it was passed. These rates improved significantly by the investigators' case accumulations and independently by calendar year. Multivariate prediction of crossing the lesion and of overall success showed that favorable lesion characteristics and increasing physician experience were more important than the patient characteristics just discussed, although both female sex and multivessel CAD remained significant independent risk factors.

Age Factors↗
PubMed1984

Efficacy of repeat percutaneous transluminal coronary angioplasty for coronary restenosis.

The short- and long-term outcome of patients within the NHLBI PTCA Registry who underwent repeat PTCA for coronary restenosis were analyzed. Of 1,880 patients in whom an initial PTCA was successful, 203 had a repeat PTCA attempted after restenosis developed. Repeat PTCA was usually performed within 6 months of the first procedure. The success rate of repeat PTCA was 85.2%. As a direct result of repeat PTCA, 1.5% of patients had an MI and 2% required emergency CABG. No patient died as a result of the attempted second procedure. One to 3 years of follow-up information was available in 94% of eligible patients. Most patients (75.9%) did not have a subsequent (third) PTCA, CABG or an MI. The late mortality rate was 0.8%. Angiographic follow-up information was available in 62 patients. Sustained enhancement of the diameter of the redilated lesion was observed in 66%. Thus, repeat PTCA has a high success and a low complication rate. Most patients did not have subsequent restenosis and are free of angina. Hence, repeat PTCA should be recommended for patients who have restenosis and should be considered as an integral component of PTCA therapy.

Angina Pectoris↗
PubMedDate not supplied

Residues of chlorinated phenols and phenoxy acid herbicides in the urine of Arkansas children.

Urine samples from 197 Arkansas children were analyzed for eight chlorinated phenols and four chlorinated phenoxy herbicides by using a new procedure that combined gas chromatography with tandem mass spectrometry. With the detection limit of 1 part per billion (ppb), six of these pesticides were detected in more than 10% of the samples. 2,5-Dichlorophenol (a metabolite of p-dichlorobenzene), and pentachlorophenol were detected in 96% and 100%, respectively, of the children's urine at median concentrations of 9 ppb and 14 ppb, respectively. 2,4,5-Trichlorophenol was detected in 54% of the children's urine at a median concentration of 1 ppb. One trichlorophenol and three other dichlorophenols were found in 3% to 27% of the samples. The herbicide 2,4-dichlorophenoxyacetic acid was observed in 20% of all samples. The concentrations of all analytes are reported as background or reference levels for use in future studies. The finding of 2,5-dichlorophenol as a ubiquitous contaminant merits further study.

2,4-Dichlorophenoxyacetic Acid↗