The function of a stem-loop in telomerase RNA is linked to the DNA repair protein Ku.

The telomerase enzyme lengthens telomeres, an activity essential for chromosome stability in most eukaryotes. The enzyme is composed of a specialized reverse transcriptase and a template RNA. In Saccharomyces cerevisiae, overexpression of TLC1, the telomerase RNA gene, disrupts telomeric structure. The result is both shortened telomere length and loss of a special chromatin structure that normally silences telomere-proximal genes. Because telomerase function is not required for telomeric silencing, we postulated that the dominant-negative effect caused by overexpression of TLC1 RNA originates in a normal interaction between the RNA and an unknown telomeric factor important for silencing; the overexpressed RNA presumably continues to bind the factor and compromises its function. Here we show that a 48-nt stem-loop structure within the 1.3-kb TLC1 RNA is necessary and sufficient for disrupting telomeric silencing and shortening telomeres. Moreover, this short RNA sequence appears to function through an interaction with the conserved DNA end-binding protein Ku. We propose that, in addition to its roles in telomeric silencing, homologous recombination and non-homologous end-joining (NHEJ), S. cerevisiae Ku also helps to recruit or activate telomerase at the telomere through an interaction with this stem-loop of TLC1 RNA.

Prospective assessment of fetal-maternal cell transfer in miscarriage and pregnancy termination.

BACKGROUND: Fetal cells (microchimerism) are acquired by women during pregnancy. Fetal microchimerism persists decades later and includes cells with pluripotent capacity. Persistent microchimerism has the capacity for both beneficial and detrimental maternal health consequences. Both miscarriage and termination of pregnancy can result in fetal microchimerism. We sought to determine whether cellular fetal microchimerism is acquired during management of pregnancy loss and further explored factors that could influence fetal cell transfer, including viability of fetal tissue, surgical versus medical management and gestational age. METHODS: Pregnant women (n= 150 samples from 75 women) with singleton pregnancies undergoing a TOP (n= 63) or treatment for embryonic or fetal demise (miscarriage, n= 12) were enrolled. Mononuclear cells were isolated from blood samples drawn before, and 30 min after, treatment. Fetal cellular microchimerism concentrations were determined using quantitative PCR for a Y chromosome-specific sequence, expressed as genome equivalents of fetal DNA per 100 000 maternal cell equivalents (gEq/10(5)). Detection rate ratios were determined according to clinical characteristics. RESULTS: Cellular fetal microchimerism was found more often in post- compared with pretreatment samples, 24 versus 5% (P= 0.004) and at higher concentrations, 0-36 versus 0-0.7 gEq/10(5) (P< 0.001). Likelihood of microchimerism was higher in surgical than medical management, detection rate ratio 24.7 (P= 0.02). The detection rate ratio for TOP versus miscarriage was 16.7 for known male fetuses (P= 0.02). Microchimerism did not vary with gestational age. CONCLUSIONS: Significant fetal cell transfer occurs during miscarriage and TOP. Exploratory analyses support relationships between obstetric clinical factors and acquisition of fetal cellular microchimerism; however, our limited sample size precludes definitive analysis of these relationships, and confirmation is needed. In addition, the long-term persistence and potential consequences of fetal microchimerism on maternal health merit further investigation.

Effects of dietary betaine on milk yield and milk composition of mid-lactation Holstein dairy cows.

Betaine, naturally found in plants and an oxidative product of choline, is converted to acetate in the rumen, which may be used for milk fat synthesis. The objective of this study was to determine the effect of supplemental dietary betaine on milk yield and milk composition. Eighteen Holstein dairy cows (126±5 d in milk; mean ± SD) were randomly assigned to a sequence of treatments of rumen-unprotected betaine at 0, 25, 50, and 100 g/d added to a standard lactation ration in a 4×4 Latin square design. Animals were fed individually with feed intake and milk yield recorded daily. Body condition score and body weight were recorded on the last day of each period that lasted 16 d, with milk sampled on the last 2 d of each period. Milk composition was determined by a Dairy Herd Improvement Association laboratory and milk fatty acids were determined by gas chromatography. Data collected over the last 2 to 3 d were analyzed using the MIXED procedure in SAS (SAS Institute Inc., Cary, NC). Milk yield (mean ± SEM) was increased by betaine when fed at 100g/d (22.4, 22.5, 22.8, 24.1±1.19 kg/d for 0, 25, 50, and 100g of betaine/d, respectively). No effect of dietary betaine was detected on dry matter intake, feed efficiency, body weight, or body condition score. Percentages of milk fat, lactose, solids-not-fat, and somatic cell count were not altered; however, protein concentration was decreased by betaine supplementation as compared with the control (3.35, 3.28, 3.27, and 3.28±0.07% for 0, 25, 50, and 100 g of betaine/d, respectively). Daily yields of milk protein, fat, lactose, energy-corrected milk, and 3.5% fat-corrected milk did not differ with betaine supplementation. Overall, inclusion of dietary betaine at 100 g/d increased milk yield, whereas all levels of betaine supplementation decreased milk protein percent and slightly altered milk fatty acid profile. Further studies are needed to determine the ruminal fermentation characteristics and the optimum rate of supplemental betaine for dairy cows.

Identification of high-copy disruptors of telomeric silencing in Saccharomyces cerevisiae.

The ends of chromosomes in Saccharomyces cerevisiae initiate a repressive chromatin structure that spreads internally and inhibits the transcription of nearby genes, a phenomenon termed telomeric silencing. To investigate the molecular basis of this process, we carried out a genetic screen to identify genes whose overexpression disrupts telomeric silencing. We thus isolated 10 DOT genes (disruptor of telomeric silencing). Among these were genes encoding chromatin component Sir4p, DNA helicase Dna2p, ribosomal protein L32, and two proteins of unknown function, Asf1p and Ifh1p. The collection also included genes that had not previously been identified: DOT1, DOT4, DOT5, DOT6, and TLC1, which encodes the RNA template component of telomerase. With the exception of TLC1, all these genes, particularly DOT1 and DOT4, also reduced silencing at other repressed loci (HM loci and rDNA) when overexpressed. Moreover, deletion of the latter two genes weakened silencing as well, suggesting that DOT1 and DOT4 normally play important roles in gene repression. DOT1 deletion also affected telomere tract length. The function of Dot1p is not known. The sequence of Dot4p suggests that it is a ubiquitin-processing protease. Taken together, the DOT genes include both components and regulators of silent chromatin.

Prudent laboratory usage, cost containment, and high quality medical care: are they compatible?

Inappropriate laboratory use by physicians is partly responsible for the rapid rise in health care costs. This use falls into three categories--over-, under-, and misutilization. Overuse creates information overload for the physician and has a detrimental effect on patient care. Abnormal results are frequently obscured by massive amounts of requested information. Studies show that laboratory use is greater for younger physicians and that increased use is not associated with better outcome of care. Overuse ranges from 26 per cent to 98 per cent for selected tests. Unnecessary tests can be eliminated with no adverse effect on quality. Laboratory use can be improved by a variety of approaches including education, feedback, implementation of administrative changes and, finally, financial incentives or disincentives; the last has proven the most effective. All the approaches should be reinforced by cost-conscious clinical settings that foster a "why" rather than a "why not" philosophy. Improving laboratory use may reduce costs and maintain quality.

Muscular strength and bone density with weight training in middle-aged women.

Previous research has demonstrated positive correlations between bone mass and both physical activity and muscular strength. There is a paucity of information describing the specific type of exercise which most benefits the human skeleton. The effects of a 1 yr weight training program on 18 middle-aged women participating in an endurance dance program (E + W) compared with 17 other women in the endurance dance program only (E) and with 19 sedentary controls (C) were studied by measuring muscular strength and bone mineral density (BMD). Eighteen women in the E + W group demonstrated increases in all strength measurements, whereas the E and C groups either had smaller increases or had declined. A significant group x test interaction term, indicating that groups responded differently over time, was observed for nondominant isokinetic elbow flexion measured through the range of motion at a constant velocity of 60 degrees.s-1 (P less than 0.05), nondominant isokinetic elbow extension at 180 degrees.s-1 (P less than 0.01), and nondominant isokinetic elbow flexion at 180 degrees.s-1 (P less than 0.05). BMD did not change significantly except that a significant group x test interaction term appeared for the radius ultradistal site (P less than 0.01). BMD of the humerus and femoral Ward's triangle increased nonsignificantly in both E and E + W over the year. This weight training program increased muscular strength but did not increase measured bone mass.

Management of blood-drawing fears in adolescents with comorbid anxiety and depressive disorders.

As more pharmacologic treatment and research on child and adolescent psychiatric patients are conducted, the common problem of blood-drawing fears will need to be addressed. Avoidance of blood-drawing could jeopardize an individual's physical and mental health, and inhibit the collection of data aimed at furthering the study of psychiatric disorders in youth. This report describes the naturalistic application of specific techniques for managing severe blood-drawing fears in adolescent subjects undergoing a clinical trial. The adolescents (ages 12-18) were 44 consecutive school refusers with comorbid anxiety and major depressive disorders. Of the school-refusing adolescents, 27% (12 of 44) were observed to have a severe fear of blood-drawing. A management strategy comprised of providing information, distraction, supportive reassurance, and exposure appeared successful in managing the fears of blood-drawing in all of the adolescents, except two. These 2 adolescents refused to enter the treatment study due to a marked fear of blood-drawing. All 10 subjects who exhibited a fear of blood-drawing and were able to complete the initial blood test, using the interventions noted, were able to obtain subsequent venipunctures with minimal or no avoidance behavior. These preliminary findings suggest that blood-drawing fears can be effectively managed in most cases, though controlled studies of these interventions are needed.

Hürthle cell adenoma diagnosed by core needle biopsy in a male patient.

Hürthle cell adenomas (HCAs) are a rare and potentially lethal variant of follicular tumors of the thyroid. Considerable controversy exists regarding potential risk factors, diagnosis, and treatment of HCAs. The authors report the case of a 38-year-old male patient with an 8.3 cm x 3.5 cm HCA. Diagnosis was made preoperatively from a core needle biopsy and confirmed postoperatively on frozen section. Treatment consisted of a right lobectomy.

Neonatal morbidity occurs despite pulmonary maturity prior to 39 weeks gestation.

OBJECTIVE: To compare outcomes among late-preterm or early-term neonates according to fetal lung maturity (FLM) status. STUDY DESIGN: We conducted a retrospective cohort study of 234 eligible singletons delivered after FLM testing before 39 weeks gestation at our center over a 2-year time period. A primary composite neonatal outcome included death and major morbidities. RESULT: The overall rate of primary composite morbidity was 25/46 (52.2%) and 61/188 (32.4%) in the immature/transitional and mature groups, respectively. After adjustment for confounders including gestational age, the composite outcome was not significantly different; adjusted odds ratio (aOR)=1.4 (confidence interval (CI)=0.7-3.0). The rate of respiratory distress syndrome was significantly higher in the immature/transitional group; odds ratio=3.4 (CI=1.1-10.3) as expected. CONCLUSION: FLM status did not correlate with the spectrum of neonatal morbidities in late-preterm and early-term births. Neonatal complications remained common in both groups.

Circumcision of neonates and children without appropriate anaesthesia is unacceptable practice.

Circumcision is painful surgery and appropriate intraoperative anaesthesia and postoperative analgesia is required. This is recognised in the policies of the Royal Australasian College of Physicians and the majority of Australian State Health Departments. Nevertheless, anecdotal evidence exists that neonatal circumcision continues to be performed in Australia with either no anaesthesia or with inadequate anaesthesia. This paper presents the evidence that neonatal circumcision is painful and reviews the available anaesthetic techniques. The authors conclude that general anaesthesia is arguably the most reliable way of ensuring adequate anaesthesia, although this may mean deferment of the procedure until the child is older. Local or regional anaesthesia for neonatal circumcision ideally requires a separate skilled anaesthetist (other than the proceduralist) to monitor the patient and intervene if the anaesthesia is inadequate. Topical anaesthesia with lignocaine-prilocaine cream is insufficient.

Aneuploidy in the normal and diseased brain.

The brain is remarkable for its complex organization and functions, which have been historically assumed to arise from cells with identical genomes. However, recent studies have shown that the brain is in fact a complex genetic mosaic of aneuploid and euploid cells. The precise function of neural aneuploidy and mosaicism are currently being examined on multiple fronts that include contributions to cellular diversity, cellular signaling and diseases of the central nervous system (CNS). Constitutive aneuploidy in genetic diseases has proven roles in brain dysfunction, as observed in Down syndrome (trisomy 21) and mosaic variegated aneuploidy. The existence of aneuploid cells within normal individuals raises the possibility that these cells might have distinct functions in the normal and diseased brain, the latter contributing to sporadic CNS disorders including cancer. Here we review what is known about neural aneuploidy, and offer speculations on its role in diseases of the brain.

Survey of combined residency programs in internal medicine and pediatrics on curricula.

Combined residency programs in internal medicine and pediatrics began to emerge during the past decade. Combined programs provide four years of training that leads to board eligibility in both disciplines. To learn more about the curricula of these programs, the authors sent a questionnaire to the directors of the 81 known combined programs. Sixty-eight such programs were active as of July 1986. Of these, 54 had been active in the 1985-86 academic year and had a total enrollment of 390 residents, an average of 7.2 residents per program. Fourteen new programs were activated in July 1986 and enrolled 46 residents, with an average of 3.3 residents per program. Virtually all the programs emphasized training in primary care and included the use of outpatient clinics where residents often work with nonphysician health-care providers. Many programs provided instruction in the use of community resources, preceptorships, and outpatient-oriented conferences and emphasized data-gathering skills. Areas that need to be addressed by program directors and the accrediting organizations are discussed by the authors.

GMENAC report on U.S. physician manpower policies: recommendations and reactions.

After four years of study in the United States, the Graduate Medical Education National Advisory Committee (GMENAC) concluded that an excess of approximately 70,000 physicians will exist in 1990. Faced with a future surplus, GMENAC recommends that U.S. medical schools decrease enrollment levels by 10 percent relative to the 1978-79 level and severely restrict entrance of foreign medical graduates. Flaws identified in the GMENAC approach relate to the use of the delphi technique, the future role of nonphysician providers, and a lack of reliable data. The GMENAC report may provide impetus for an abrupt shift from expansionism to reductionism in U.S. physician manpower policy. Long range physician manpower planning has erred in the past, necessitating periodic reevaluation of national policy. A continuing balance between supply and demand, although ideal, can probably never be attained. Thus small adjustments in total supply and specialty mix will always be necessary. The GMENAC report, which is the most comprehensive study of U.S. physician manpower to date, requires serious consideration in this context.

A calcified fibrocartilagenous nodule in the ligamentum nuchae. Presenting as a tumor.

Nodules of fibrocartilage, calcified fibrocartilage, or bone may be found in the adult ligamentum nuchae. These are generally asymptomatic but may mimic fractures or, as in the case presented here, tumors.

Evaluation and validation of a course in practice management for senior residents.

Many doctors reach the end of their specialist training to find that they need to cope well and efficiently with the business aspects of setting up and managing a medical practice-yet this has frequently been ignored in their education. This article describes the design and evaluation of a course in practice management offered to doctors near the end of their specialist training.

Community-based Practitioners as Medical Student Preceptors-Dispelling an Old Myth.

This study was designed to compare the teaching abilities of community-based preceptors and university-based clinical faculty, as judged by two matched groups of students. On only one of 13 dimensions of clinical teaching was there a significant difference between the preceptors and university-based faculty: preceptors were reported to use demonstrations less than their university-based colleagues. The study shows that despite their other commitments and lack of formal training in didactic skills, community-based practitioners can provide sound educational experiences and, in the students' opinions, are as competent teachers as clinical, university-based faculty.