Search PubMed⌕ Search

Biomedical subjects

C McLaughlin

Publications and source records attributed to C McLaughlin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Terminal syringohydromyelia and occult spinal dysraphism.

Terminal syringohydromyelia is a cystic dilatation of the lower third of the spinal cord. The authors describe its incidence and characteristics, its frequent association with occult spinal dysraphism, and its clinical significance and need for surgical treatment. All 143 cases of occult spinal dysraphism treated at the Duke University Medical Center between 1972 and 1992 were reviewed. A terminal syrinx was found in 24 (27%) of the 90 cases that were evaluated by magnetic resonance (MR) imaging. In contrast three (6.2%) of 48 cases evaluated by myelography and postmyelographic computerized tomography had a syrinx documented. The relative radiographic severity of the different syringes was estimated by using measurements of the syrinx and spinal cord on the MR images, classifying the cysts into large and small. Large syringes were frequently symptomatic, commonly presenting with pain, motor and sensory deficits of the lower extremities, scoliosis, and bowel and bladder dysfunction. Terminal syringohydromyelia with occult spinal dysraphic lesions was most often associated with tethered spinal cord from a tight filum terminale in the presence of an anorectal anomaly (67% of cases), meningocele manqué (54%), and diastematomyelia (38%). An infrequent association was seen with other spinal cord anomalies. The results of surgical management of terminal syringohydromyelia were analyzed, highlighting the necessity and effectiveness of shunting the large cysts, especially in the setting of a progressive symptomatology. Of the 11 patients with shunts who underwent MR imaging, 10 showed either complete or significant resolution of the syrinx; all five patients who had presented with pain (mainly back pain) showed complete resolution of the pain after shunting; finally, one-third of patients with shunt placement had significant postoperative improvement in their neurological examination, whereas none worsened. It is stressed that terminal syringohydromyelia is an important pathological entity that should be considered in patients with occult spinal dysraphism, and treated surgically when clinically or radiographically significant.

Adolescent↗
PubMed1992

Relative ear advantage and element duration.

Lauter [J. Acoust. Soc. Am. 71, 701-707 (1982)] reported that although the magnitude and direction of the absolute ear advantage for speech and nonspeech sound sets presented dichotically varies considerably among listeners, consistent patterns of a relative ear advantage (EArel) across sound sets are preserved from listener to listener. She further claimed that EArel appeared to be related to the duration of elements that composed a sequence. The existence of EArel is investigated for four sound sets: CV nonsense syllables and pitch patterns that were composed of 50-, 80-, or 120-ms tones. The paradigm was target monitoring, a Yes/No task in which listeners attended to only one ear and listened for the presence of a target signal. The results failed to confirm that listeners have a consistent relative ear advantage related to element duration for nonspeech sound sets.

Acoustics↗
PubMed1987

Familial premature ovarian failure due to an interstitial deletion of the long arm of the X chromosome.

We describe a family in which four women had menstrual irregularities and a partial deletion of the long arm of the X chromosome (Xq). Three of the four women had premature ovarian failure (at the ages of 24 to 37 years). Chromosome-banding studies initially suggested that a terminal portion of Xq was deleted. However, DNA-hybridization studies showed that an interstitial portion of Xq was deleted and that the affected women had a 46,XX,del(X)(pter-q21.3::q27-qter) karyotype. These findings help clarify the role of Xq in ovarian function and indicate that the accurate description of such abnormalities requires a combination of cytogenetic and DNA-hybridization analysis.

Adult↗
PubMed1986

Competition versus regulation: some empirical evidence.

In response to dramatic rises in health care costs, policymakers have been debating the relative merits of regulatory and competitive strategies as a means of containing costs. One major activity espoused by proponents of competition is the growth of health maintenance organizations (HMOs) which, in their opinion, will result in the market better determining efficient levels of utilization and costs. Extending this argument, the larger the percent of the population in a market area who enroll in HMOs, the greater the market-forcing effect of HMOs in reducing overall hospital expenditures; that is, if HMOs are providing lower-cost care, then the fee-for-service system will be forced to reduce costs in order to be competitive. The authors studied the 25 largest SMSAs from 1971-1981, and controlling for environmental conditions in each market, they examined the impact of both HMO growth and regulatory activity on costs and utilization. They conclude that neither competition nor regulation had a significant impact in reducing overall hospital costs. While there may have been some impact in specific communities, no generalizable effect could be observed. However, the authors did find that increases in costs and utilization were essentially driven by supply factors such as the number of hospital beds or medical specialists in a given community.

Catchment Area, Health↗
PubMed1986

Characteristics of support for mandatory licensure among respondents to a state-wide survey.

Members of the Ohio Dietetic Association were surveyed by a mail-return method beginning on January 10, 1984, to ascertain attitudes toward mandatory licensure among dietitians. Of the 2,435 members surveyed, 2,037 (83.7%) responded. Results indicated that 73.3% of respondents would support a mandatory licensure law if it were made equivalent to current Commission on Dietetic Registration (CDR) requirements. Four of every five members identified with "public regarding" arguments in favor of licensure. Assuming licensure, the majority of members expressed support of a "CDR-like" licensure examination followed by continuing education requirements for renewal. Support, however, was significantly related to whether a mandatory licensure law included a "grandfather" clause. Without such a clause, support fell to about 48%. Discriminant analysis revealed that age and years of experience in the field of dietetics were the most important variables for differentiating between supporters and opponents of licensure without a grandfather provision. The results suggest that the demographic composition of dietitians in states considering adopting mandatory licensure provisions will largely determine the support for or opposition to such a law.

Adult↗
PubMed1984

Voltage-gated potassium channels are required for human T lymphocyte activation.

The calcium channel blockers, verapamil and diltiazem, inhibit phytohemagglutinin (PHA)-induced mitogenesis at concentrations that block the T lymphocyte K channel currents. K channel blockers also inhibit the allogeneic mixed lymphocyte response in a dose-dependent manner with the same potency sequence as for block of K currents. K channel blockers inhibit PHA-stimulated mitogenesis only if added during the first 20-30 h after PHA addition, but not later, indicating a requirement for functional K channels during this period. We investigated the effect of K channel blockers on various aspects of protein synthesis for two reasons: first, protein synthesis appears to be necessary for the events leading to DNA synthesis, and second, the increase in the protein synthetic rate commences during the first 24-48 h after PHA addition. PHA-induced total protein synthesis was reduced to the level in unstimulated T lymphocytes by K channel blockers in a dose-dependent manner with the same potency sequence as for the block of K currents and inhibition of [3H]thymidine incorporation. Two-dimensional gel electrophoresis demonstrated that although the synthesis of the majority of proteins was reduced by K channel blockers to the level in unstimulated T cells, some proteins continued to be synthesized at an enhanced rate compared with resting cells. Two proteins, S and T, detected by two-dimensional gel electrophoresis in unstimulated T lymphocytes, appeared to be reduced in intensity in gels of PHA-treated T lymphocytes, in contrast to the increased synthesis of the remaining proteins. 4-Aminopyridine (4-AP), at concentrations that inhibit protein synthesis, prevented the apparent PHA-induced reduction of proteins S and T. These proteins may play a role in maintaining the T lymphocyte in a resting state and may be related to the translation inhibitory factors reported to be present at a higher specific activity in quiescent T lymphocytes than in PHA-activated T cells. The expression of the IL-2 receptor (Tac) during T lymphocyte activation was not altered by K channel blockers, whereas the production of interleukin 2 (IL-2) was reduced to the level in unstimulated T lymphocytes. Exogenous IL-2 partially relieved the inhibition of mitogenesis by low, but not by high, concentrations of 4-AP. These experiments clarify the role of K channels in T lymphocyte activation and suggest that functional K channels are required either for protein synthesis or for events leading to protein synthesis.

4-Aminopyridine↗
PubMed1980

Proliferative disorders of the breast as risk factors for breast cancer in a self-selected screened population: pathologic markers.

A study was done to quantify the pathologic risk of subsequent breast cancer in women whose biopsies demonstrated proliferative histologic conditions. Out of a total of 10,530 patients, 1,408 had biopsies which were classified as either bland fibrocystic or hyperplastic. The behavior of the disease in these patients was compared to that of the general screened population. It was concluded that women whose biopsies reveal hyperplastic disorder, primarily atypical hyperplasia and fibroadenoma, run the greatest risk of getting cancer. For women with atypical hyperplasia, the risk is 13 times that of the general population, and for those with fibroadenoma it is three times greater.

Breast Diseases↗
PubMed1980

Mammographic patterns as markers for high-risk benign breast disease and incident cancers.

A study was done to determine whether the risk of cancer development can be calculated through the use of mammographic patterns. Hyperplasia, bland fibrocystic disease, and incident cancers were correlated with Wolfe's mammographic classification scheme. Intraobserver and interobserver consistency were measured in the 8,033 classified mammograms. Maximum observer agreement was achieved by combining high-risk and low-risk categories. The data presented do not support the contention that diffuse mammographic patterns are useful predictors for determining strategies of screening or patient management; large-scale studies are needed before mammographic classification is adopted.

Adult↗
PubMed1979

The half-life of mRNA in Saccharomyces cerevisiae.

The decay kinetics of mRNA was studied in a yeast temperature-sensitive mutant, ts136, which is defective in cytoplasmic RNA production at 37 degree C. The disappearance of the synthetic capacity of mRNA was determined by withdrawing equal volumes of ts136 cell culture and pulse-labelling with [35S]methionine at various time intervals after the shift to 37 degrees C from 23 degrees C. The synthesized proteins were separated on a two-dimensional gel electrophoretic system and then quantitatively analyzed for theri incorporated radioactivities by scintillation counting. Our results show that yeast mRNAs have divergent functional half-lives ranging from 4.5 to 41 min, with an average value of 22 min. Each mRNA exhibits a simple exponential decay with its own characteristic dacay pattern. Of the approximately 500 major polypeptides made by yeast cells, which are detectable on autoradiograms of the gels, 80 were arbitrarily selected and the mRNAs coding for those polypeptides were examined for their decay kinetics.

Electrophoresis↗
PubMed1976

Career preferences of doctors graduating in 1974.

Questionnaires were sent to all 2348 doctors who had graduated from medical schools in England, Scotland, and Wales in 1974 asking about their career preferences. Most were in their second preregistration post, and the response rate was 86-1%. The most popular first choice of career was general practice (665 of the responders; 32-9%), followed by medicine (454; 22-5%), surgery (321; 15-9%), and paediatrics (129; 6-4%). Only 507 of the responders (25-1%), however, stated that their preference was "definite". First choices differed widely between men and women graduates and between graduates of different medical schools.

Adult↗
PubMed1975

Future prospects for British graduates and the health service.

What are the prospects, in the National Health Service, for the increasing output of British medical schools? A comparison of the numbers of training and career posts likely to be available in N.H.S. hospitals with the probable requirements of British graduates seeking training suggests that the supply of senior-house-officer and registrar posts will far exceed the demand, so that dependence on overseas doctors is likely to continue. The number of senior-registrar posts should ensure that the present percentage of graduates become consultants, but available consultant posts seem likely to exceed the output of qualified applicants. The only grade for which demand looks likely to exceed supply is the compulsory preregistration grade: in three years' time medical-school output could be greater than the number of approved posts.

Career Mobility↗
PubMed1973

Modification of ribosomes in cryptopleurine-resistant mutants of yeast.

Cryptopleurine-resistant mutants of Saccharomyces cerevisiae were isolated. A single, recessive nuclear gene, very closely linked to the mating locus (2.1 centimorgans), is responsible for resistance. Ribosomes from the mutants were found to be resistant to cryptopleurine when analyzed by poly(U)-directed polyphenylalanine synthesis. Analysis of the distribution of ribosomes between monosomes and polysomes in sensitive cells exposed to cryptopleurine suggests that some step is inhibited during the elongation phase of protein synthesis.

Alkaloids↗