Potential deferral criteria predictive of human immunodeficiency virus positivity among blood donors in Thailand

Background: To develop deferral criteria to prevent human immunodeficiency virus (HIV) transmission by recently infected blood donors in the seronegative “window” phase, routine data on donors at a university hospital were examined for factors predicting seropositivity. Study Design and Methods: Records of all 281 HIV- positive blood donors from August 1987 through September 1991 were retrospectively compared with those of 1076 randomly selected control donors matched only by year of donation. Four controls were selected for each HIV-positive donor. Results: The prevalence of HIV in 102,684 donor units during the period rose from 0.02 percent in 1987 to 0.52 percent in 1991. Multivariable analysis revealed that male sex (odds ratio [OR] = 26.4), VDRL test positivity (OR = 3.0), age 21 to 30 years (OR = 2.2; referent: 16–20-year-old group), and replacement donorship (OR = 1.4; referent: voluntary donors) were independent factors significantly associated with HIV positivity among these donors (p < 0.05). Since replacement donorship cannot be avoided, only male sex, age 21 to 30 years, and VDRL test positivity were considered as potential criteria. When these findings were extrapolated to all donors in 1990 and 1991, those with all three or only two (excluding VDRL test, because the results are known only after donation) of these high- risk factors had HIV positivity probabilities of 2.2 and 1.0 percent, respectively. These probabilities were, respectively, 4.9 times (95% CI: 2.9 8.3) and 4.1 times (3.1, 5.4) the risk among other donors. However, applying such criteria would have eliminated 1.5 and 31.2 percent, respectively, of all HIV-negative donors in 1990 and 1991. The latter deferral proportion is too high to be acceptable. Conclusion: In Thailand, improved donor deferral criteria addressing sexual risk factors could lead to decreased probability of window-period donation, with an acceptable rate of deferral. Additional p24 antigen testing may be indicated for donors at increased risk for HIV infection, specifically, men aged 21 to 30.     

In vivo H-1 spectroscopy in humans at 1.5 T

Water-suppressed and section-selective proton (hydrogen-1) magnetic resonance (MR) spectra were recorded from human brain, leg muscle, liver, and heart with a 1.5-T imager. Signal from water was well suppressed, and resonances from several metabolites were consequently seen. The spectra from brains of healthy volunteers (n = 5) showed resonances from N-acetylaspartate, glutamine, aspartate, phosphocreatine/creatine, choline, taurine, and glycine. In five large brain meningiomas, resonances from N-acetyl-aspartate and phosphocreatine/creatine were either not visible or markedly decreased in intensity. The spectra from leg muscles of healthy volunteers showed resonances from protons in saturated fatty acyl chains, whereas resonances from unsaturated fatty acyl chains predominated in spectra from leg muscles of two patients with spina bifida. The spectra from livers of three healthy volunteers showed resonances from aliphatic and aromatic amino acids, choline, carnitine, and both saturated and unsaturated fatty acyl chains, and spectra from hearts of six healthy volunteers showed major resonances from phosphocreatine/creatine and taurine and smaller resonances from amino acids and fatty acyl chains.     

Radiographically negative avascular necrosis: detection with MR imaging

To correlate the morphologic appearance on magnetic resonance (MR) images of radiographically negative avascular necrosis (AVN) of the femoral head with that on computed tomographic (CT) and radionuclide scans, the radiographic and clinical records of 24 patients were reviewed retrospectively. In 18 patients the MR signal intensity features were monitored by means of serial imaging. All MR studies included T1-weighted (short repetition time [TR], short echo delay time [TE] ) imaging and T2-weighted imaging (long TR, long TE). Thirty-one hips were determined with MR to be involved by AVN; 27 were staged on the basis of signal intensity characteristics within the low-intensity rim. Core decompression was performed on 18 hips. Afterward, progression of disease occurred in only one hip. Fourteen of the 16 asymptomatic patients (88%) had early-stage focal lesions. CT scans were obtained in 15 patients and radionuclide scans in 21. Ten hips at radionuclide imaging and five at CT appeared normal when MR results were distinctly abnormal. MR can depict early radiographically negative AVN in asymptomatic individuals. At this early stage, the lesions in this series appear to be nonprogressive after treatment.     

髋关节置换后股骨假体无菌性松动分析

髋关节置换包括全髋和半髋置换,是治疗髋关节严重病损的有效手段,但假体松动是手术失败的主要原因。早期假体松动归因于应力遮挡引起的骨质重新塑形导致骨溶解,晚期假体松动的原因主要是假体微动和磨损颗粒引起骨溶解,近年来对股骨假体松动的研究更为广泛。从宏观动力学研究到细胞分子生物学研究,本文就近年来对髋关节置换后股骨假体松动作一系统性综述。     

Frequent low-dose misoprostol for termination of second-trimester pregnancy

Objectives?To determine the efficacy of an application regimen of low-dose frequent misoprostol for second-trimester pregnancy termination.

Methods?A total of 250 women between 12 and 20 weeks of gestation who were scheduled for second-trimester pregnancy termination received 200?μg vaginal misoprostol followed by 100?μg oral misoprostol every 2?h until expulsion of the fetus. Mechanical cervical dilatation with a 16-French Foley balloon catheter was performed if no cervical dilatation was observed after 24?h. The main outcome measures were the delivery rate within 24?h and the factors influencing the interval between the onset of induction and abortion. Secondary outcome measures were the side-effects of the regimen and the total misoprostol dose required.

Results?With application of this protocol, 245 women (98%) delivered within 24?h of induction. The mean (± standard deviation) misoprostol dose used was 728?±?297?μg (200–2100?μg). Cox regression analysis revealed that vaginal spotting or nulliparity do not effect the induction–abortion time. On the other hand, using this regimen induction to abortion time tends to be longer in the presence of live fetuses (odds ratio (OR)?=?0.45; confidence interval (CI)?=?0.2–0.8; p?=?0.008) and pregnancies with gestational age >?16 weeks (OR?=?0.59; CI?=?0.4–0.8; p?=?0.003) when compared with cases of in utero death and pregnancies with a gestational age of 12–13 weeks, respectively. Twenty-seven women (10.8%) experienced one or more side-effects attributable to misoprostol.

Conclusion?The 100-μg oral misoprostol every 2?h following 200?μg vaginal misoprostol is a highly effective protocol for inducing abortion at 12–20 weeks of pregnancy. Cases with live fetuses or pregnancies with older gestational age (>?16 weeks) deliver in a longer time period.     

Drug resistance in multiple myeloma associated with high in vitro incorporation of 3H-thymidine

In multiple myeloma, tumor cell mass and labeling index correlate with subsequent survival duration, but do not predict for response to treatment. In the present study was have autoradiographically measured the incorporation of 3H-thymidine as determined by the number of grains over the myeloma nuclei in bone marrow aspiration samples. In 33/37 patients with less than 50% tumor regression or progressive disease, the pretreatment grain count was greater than or equal to 20/myeloma nucleus. Conversely, values of less than 20 were found in 27/29 patients who had greater than or equal to 50% cell mass reduction. Survival duration was significantly better than (p less than 0.001) in patients with grain counts less than 20. Sixty percent of the patients with both a low labeling index (less than or equal to 3%) and grain count (less than 20) were alive at 48 mo, whereas 15/17 patients with a high labeling index and grain count had a median survival of less than 6 mo. In a subset of 22 patients, there as a significant correlation between in vitro resistance to melphalan, adriamycin, and vincristine as tested in the myeloma stem cell colony assay system and a grain count of greater than 20. We can only speculate as to the reasons for the increased 3H-thymidine uptake by myeloma cells resistant to treatment, however, it could be associated with accumulation of excess DNA and /or increased unscheduled DNA synthesis following injury from alkylating agents.     

Adnexal masses: MR imaging observations at 1.5 T, with US and CT correlation

To assess the role of 1.5-T magnetic resonance (MR) imaging in evaluation of the adnexa, 43 consecutive examinations that revealed 61 adnexal masses were retrospectively reviewed. T1- and T2-weighted images in coronal, axial, and/or sagittal planes were included. Available ultrasound (US) (n = 30) and/or computed tomographic (CT) (n = 9) scans were then correlated with the MR images. On T2-weighted images at least part of all adnexal masses was of higher signal intensity than surrounding muscle and adipose tissue, and therefore the adnexal masses were best seen with these sequences. T1-weighted imaging improved tissue characterization by revealing signal characteristics of fat in teratomas and characteristics of blood in endometriomas or hemorrhagic cysts, pelvic inflammatory disease, ovarian carcinomas, serous cystadenomas, and teratomas. MR imaging provided additional information or increased diagnostic confidence in 25 of 30 patients who underwent US or CT. MR imaging is a promising problem-solving modality after US in the study of adnexal abnormalities.     

Twin gestations: monitoring of complications and anomalies with US

An evaluation of 227 consecutive twin gestations was undertaken to assess the role of ultrasound (US) in the diagnosis of major obstetric complications and congenital anomalies. US accurately depicted the growth and development of fetuses in 65 patients with underlying maternal disorders that produced additional risks to the pregnancy. Complications such as malpresentations (104 cases), polyhydramnios (15 cases), oligohydramnios (five cases), and uterine myomas (seven of 11 cases) were demonstrated prenatally with US. Fetal anomalies included anencephaly (two cases), hydrocephalus (two cases), conjoined twins (three cases), twin-twin transfusion syndrome (five cases), and acardiac monsters (two cases). Demise of one twin in 20 gestations and demise of both twins in 18 gestations (overall mortality of 17%) were correctly identified with US. These 38 gestations included intrauterine demise in 12, spontaneous abortion in 13, and neonatal deaths in 13. Therefore, when multiple gestations are suspected clinically, serial real-time US scans should be obtained beginning in the first trimester.