S-adenosylmethionine increases erythrocyte ATP in vitro by a route independent of adenosine kinase

The mechanism by which S-adenosylmethionine (SAM) and adenosine (Ado) increase ATP levels in intact human erythrocytes in vitro has been compared. The use of erythrocytes from healthy controls and from subjects totally deficient in adenine phosphoribosyltransferase (APRT), plus inhibitors of adenosine kinase (AK) and adenosine deaminase (ADA) separately and together, has enabled us to demonstrate that this increment in ATP levels occurred via totally different metabolic routes. The results show that: (i) whilst the Ado-induced increment in ATP was AK dependent, that produced by SAM was independent of AK; and (ii) the SAM-induced increment in ATP was totally dependent on APRT and that some of the increment produced by Ado might also be APRT dependent. The above data are consistent with the metabolism of SAM to ATP by a route recently identified by us whereby ATP is formed from deoxyadenosine: namely binding to the enzyme S-adenosylhomocysteine hydrolase with subsequent release of adenine and further conversion to ATP via APRT.     

不确定RIBA结果在HCV感染诊断中的预测意义

目的:评价诊断丙肝病毒(HCV)感染时不确定的重组免疫印迹试验(R IBA)结果的预测意义。方法:从1550份血清结果中筛选出142份不确定结果进行回顾性分析,分别分析4个条带出现单反应的几率及其预测意义。结果:142份不确定结果中单条带反应率分别为:c33c 51%,c-22(p)36%,N S5 11%,C 100(p)2%。各单反应条带中酶免法(E IA)结果呈高滴度同时多聚酶链反应(PCR)结果呈阳性的率分别为:c33c 60%,c-22(p)26%,N S5 8%,c100(p)0%。4个单反应条带中E IA与PCR同时呈阴性的率相同。结论:R IBA4个条带出现单条带反应的几率不同;4个条带中c33c的阳性预测值最高,为60%,提示c33c单阳性预示很可能感染HCV,其它三个条带的阳性预测值较低且无差异;4个条带的假阳性预测值低且无差异,提示单条带阳性者未感染HCV的可能性小。     

DXA-Generated Z-Scores and T-Scores May Differ Substantially and Significantly in Young Adults

Central dual-energy X-ray absorptiometry (DXA) is the gold standard for non-invasive measurement of bone mineral density (BMD). Using this value and subject demographics, DXA software calculates T-scores and Z-scores. Professional society guidelines for the management of osteoporosis are based on T-scores and Z-scores, rather than on the actual BMD value. Although one expects T-scores and Z-scores to be very similar in young men and women for any given BMD measurement, little literature exists on this issue. Our clinical experience shows that some younger adult individuals (premenopausal women and men younger than 50 yr) have larger than expected difference between their DXA T-score and Z-score. This cross-sectional study evaluates the extent of this discordance between Z-scores and T-scores in a sample of 4275 men and women aged 20–49 yr. All subjects were scanned by central DXA using equipment manufactured by GE Lunar, GE, Madison, WI, or Hologic, Inc., Bedford, MA. Significant differences between Z-scores and T-scores were seen within individuals at the lumbar spine, total hip, femoral neck, and trochanter (p value < 0.001) for both DXA systems. Although these differences were less than half a standard deviation (SD) in most instances, the magnitude of difference was substantial at times, being 1 or more SD in up to 11% of cases (range: −1.95 to +1.54 SD). The smallest differences were seen at the total hip and the largest differences were seen at the femoral neck for both technologies. This is in part because there is no single standard Z-score definition, resulting in different methods of calculation across, and even within, DXA manufacturers. Standardization of Z-score definition and method of calculation is indicated. DXA Z-scores should be interpreted with caution in men and women aged 20–50 yr.     

Controversies in the management of cerebrovascular disease in older patients.

Several ongoing studies are evaluating the optimal management of patients with cerebrovascular disease. The Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin (CASANOVA) study has shown that carotid endarterectomy is not recommended for asymptomatic patients with less than 90% carotid stenosis. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgical Trial (ECST) have demonstrated that endarterectomy should be considered for patients who had recent carotid artery territory ischemic symptoms associated with angiographically defined stenosis of greater than 70%. These and other trials are expected to provide further data regarding management of cerebrovascular disease, including treatment of those patients with moderate (30 to 69%) carotid stenosis. Until that time, treatment decisions must be made on a case-to-case basis.     

Quality of life in inflammatory bowel disease.

Quality of life with inflammatory bowel disease has not been well examined. Recently, a questionnaire to determine subjective health status for patients with inflammatory bowel disease has been developed and verified. To examine the quality of life in a group of "well" outpatients with inflammatory bowel disease, we developed a self-administered form of this questionnaire containing 36 questions identifiable to five dimensions: systemic symptoms, bowel symptoms, functional impairment, social impairment, and emotional function. We identified outpatients with inflammatory bowel disease through the local chapter of the Ileitis and Colitis Foundation and distributed 396 questionnaires, by mail, with 182 being returned completed (46% response rate). Forty-eight age- and sex-matched controls filled out and returned an identical questionnaire. Response options for each question were framed on a seven-point scale in which 7 represented best function and 1 represented worst function. Male-to-female ratio and mean age were similar to those of controls for the inflammatory bowel disease group. In each dimension, as well as globally, the quality of life of patients with inflammatory bowel disease was significantly worse than that for their age- and sex-matched controls. In conclusion, this survey demonstrates that inflammatory bowel disease adversely affects quality of life in a highly motivated group of "well" outpatients when compared to an age- and sex-matched population.     

Growth hormone benefits children with 18q deletions

Most individuals with constitutional deletions of chromosome 18q have developmental delays, dysmyelination of the brain, and growth failure due to growth hormone deficiency. We monitored the effects of growth hormone treatment by evaluating 23 individuals for changes in growth, nonverbal intelligence quotient (nIQ), and quantitative brain MRI changes. Over an average of 37 months, the treated group of 13 children had an average nIQ increase of 17 points, an increase in height standard deviation score of 1.7, and significant change in T1 relaxation times in the caudate and frontal white matter. Cognitive changes of this magnitude are clinically significant and are anticipated to have an effect on the long-term outcomes for the treated individuals.     

Oculoauriculovertebral anomaly: Segregation analysis

Seventy-four families of probands with oculoauriculovertebral anomaly were evaluated, including 116 parents and 195 off-spring. Relatives were examined to identify ear malformations, mandibular anomalies, and other craniofacial abnormalities. For segregation analysis using POINTER, selection of the sample was consistent with single as-certainment. Different population liabilities were used for probands and relatives, because affection was narrowly defined for probands and broadly defined for relatives. The hypothesis of no genetic transmission was rejected. The evidence favored autosomal dominant inheritance; recessive and polygenic models were not distinguishable. © 1992 Wiley-Liss, Inc.