广泛性甲状腺切除治疗原发性甲状腺功能亢进

目的探讨原发性甲状腺功能亢进的手术治疗。方法回顾性分析33例原发性甲状腺功能亢进症患者手术治疗的临床资料,行双侧近全切除30例,一侧全切加对侧次全切2例,双侧全切除1例。结果本组无死亡病例,双侧全切除患者术后发生永久性喉返神经瘫痪伴甲状旁腺功能低下。所有病例经随访2-18月,无1例复发,5例出现甲状腺功能减退,采用甲状腺素替代治疗效果满意。结论手术是治疗原发性甲状腺功能亢进的安全有效办法,推荐术式为甲状腺近全切除术,强调围手术期处理,熟练掌握手术技巧可防止手术并发症。     

Application of 23Na MRI to monitor chemotherapeutic response in RIF-1 tumors

Effects of an alkylating anticancer drug, cyclophosphamide (Cp), on 23Na signal intensity (23Na SI) and water apparent diffusion coefficient (ADC) were examined in subcutaneously-implanted radiation-induced fibrosarcoma (RIF-1) tumors by 23Na and 1H magnetic resonance imaging (MRI). MRI experiments were performed on untreated control (n = 5) and Cp-treated (n = 6) C3H mice, once before Cp injection (300 mg/kg) then daily for 3 days after treatment. Tumor volumes were significantly lower in treated animals 2 and 3 days posttreatment. At the same time points, in vivo MRI experiments showed an increase in both 23Na SI and water ADC in treated tumors, whereas control tumors did not show any significant changes. The correlation between 23Na SI and water ADC changes was dramatically increased in the Cp-treated group, suggesting that the observed increases in 23Na SI and water ADC were caused by the same mechanism. Histologic sections showed decreased cell density in the regions of increased 23Na and water ADC SI. Destructive chemical analysis showed that Cp treatment increased the relative extracellular space and tumor [Na+]. We conclude that the changes in water ADC and 23Na SI were largely due to an increase in extracellular space. 23Na MRI and 1H water ADC measurements may provide valuable noninvasive techniques for monitoring chemotherapeutic responses.     

Devascularizing complications of free fibula harvest: peronea arteria magna

The authors present a case report of devascularizing complications following free fibula harvest. A retrospective review of 93 consecutively imaged limbs demonstrated a peronea arteria magna (PAM) prevalence of 5.3 percent in an urban population, which was used to perform a cost-effectiveness analysis for preoperative vascular imaging of the donor limb using magnetic resonance angiography (MRA) and traditional angiography (TA). Donor-site complications of fibula harvest range from 15 to 30 percent, but are rarely limb-threatening. Limb loss is a dreaded complication of congenital PAM, which can be present with a normal vascular exam. Some microsurgery groups advocate using no preoperative imaging of the donor limb; they rely on intraoperative assessment of the vascular anatomy. An aborted harvest due to aberrant anatomy leads to both direct and indirect added costs. The authors believe that MRA imaging of the donor limb, being minimally invasive, is cost-effective and indicated for free fibula transfers. For equivocal results, conversion to more invasive and costly TA may be necessary.     

Tuberculosis transmission in nontraditional settings: a decision-tree approach

BACKGROUND: Tuberculosis (TB) transmission in nontraditional settings and relationships (non-TSR) often eludes detection by conventional contact investigation and is increasingly common. The U.S.-based National Tuberculosis Genotyping and Surveillance Network collected epidemiologic data and genotyping results of Mycobacterium tuberculosis isolates from 1996 to 2000. METHODS: In 2003-2004, we determined the number and characteristics of TB patients in non-TSR that were involved in recent transmission, generated a decision tree to profile those patients, and performed a case-control study to identify predictors of being in non-TSR. RESULTS: Of 10,844 culture-positive reported TB cases that were genotyped, 4724 (43.6%) M. tuberculosis isolates were clustered with at least one other isolate. Among these, 520 (11%) had epidemiologic linkages discovered during conventional contact investigation or cluster investigation and confirmed by genotyping results. The decision tree identified race/ethnicity (non-Hispanic white or black) as having the greatest predictive ability to determine patients in non-TSR, followed by being aged 15 to 24 years and having positive or unknown HIV infection status. From the 520, 85 (16.4%) had non-TSR, and 435 (83.6%) had traditional settings and relationships (TSR). In multivariate analyses, patients in non-TSR were significantly more likely than those in TSR to be non-Hispanic white (adjusted odds ratio [aOR]=6.1; 95% confidence interval [CI]=1.7-21.1]) or to have an M. tuberculosis isolate resistant to rifampin (aOR=5.2; 95% CI=1.5-17.7). CONCLUSIONS: Decision-tree analyses can be used to enhance both the efficiency and effectiveness of TB prevention and control activities in identifying patients in non-TSR.     

Identifying high-risk asymptomatic diabetic patients who are candidates for screening stress single-photon emission computed tomography imaging

OBJECTIVES: The purpose of this study was to identify which asymptomatic diabetic patients are candidates for screening single-photon emission computed tomography (SPECT) imaging and to examine angiographic findings and mortality in patients according to SPECT imaging categories. BACKGROUND: Previously we reported a high percentage of abnormal and high-risk SPECT imaging scans in asymptomatic diabetic patients. METHODS: We examined the associations between several clinical and laboratory variables and a high-risk stress SPECT imaging scan in 1,427 asymptomatic diabetic patients without known coronary artery disease (CAD). Results of coronary angiography and long-term outcome were also analyzed. RESULTS: An abnormal stress SPECT imaging scan was present in 826 patients (58%) and a high-risk scan in 261 patients (18%). Multivariate analysis demonstrated that seven variables were independently associated with a high-risk scan (model chi-square=107, p <0.0001). The two most important variables were electrocardiogram (ECG) Q waves (adjusted chi-square=38.3, p <0.001) and peripheral arterial disease (PAD) (adjusted chi-square=13.9, p <0.001). Coronary angiography was performed in 127 (49%) high-risk SPECT imaging patients, 61% of whom had angiographic high-risk CAD. Annual mortality rates for patient subsets categorized by SPECT imaging scans were high-risk 5.9%, intermediate-risk 5.0%, and low-risk 3.6% (p <0.001 for differences between groups). CONCLUSIONS: High-risk findings on stress SPECT imaging were present in 18% of asymptomatic diabetic patients without known CAD. Patients with high-risk scans had a high prevalence of severe CAD and a high annual mortality rate. ECG Q waves and/or evidence of PAD identified the most suitable candidates for screening.     

Transesophageal two-dimensional echocardiographic identification of hiatal hernia

We report a case of a middle-aged woman in whom a transesophageal echocardiogram showed a mass-like lesion posteriorly near the descending thoracic aorta. We were able to make a definitive diagnosis of this mass as a hiatal hernia because of a thick inner lining measuring 6-9 mm in thickness similar to the stomach mucosa, and the presence of a few microbubbles within the mass. In addition, the microbubbles increased considerably after 10 cc of agitated normal saline flush via a nasogastric tube.     

Live three-dimensional right parasternal and supraclavicular transthoracic echocardiographic examination

In the present study, we describe the usefulness of the recently developed technique of live three-dimensional transthoracic echocardiography in the assessment of normal cardiac structures and adjacent vessels using the right parasternal and supraclavicular approaches. Examples of some abnormalities diagnosed from these approaches are also illustrated.     

Engineering of protease variants exhibiting high catalytic activity and exquisite substrate selectivity

The exquisite selectivity and catalytic activity of enzymes have been shaped by the effects of positive and negative selection pressure during the course of evolution. In contrast, enzyme variants engineered by using in vitro screening techniques to accept novel substrates typically display a higher degree of catalytic promiscuity and lower total turnover in comparison with their natural counterparts. Using bacterial display and multiparameter flow cytometry, we have developed a novel methodology for emulating positive and negative selective pressure in vitro for the isolation of enzyme variants with reactivity for desired novel substrates, while simultaneously excluding those with reactivity toward undesired substrates. Screening of a large library of random mutants of the Escherichia coli endopeptidase OmpT led to the isolation of an enzyme variant, 1.3.19, that cleaved an Ala-Arg peptide bond instead of the Arg-Arg bond preferred by the WT enzyme. Variant 1.3.19 exhibited greater than three million-fold selectivity (-Ala-Arg-/-Arg-Arg-) and a catalytic efficiency for Ala-Arg cleavage that is the same as that displayed by the parent for the preferred substrate, Arg-Arg. A single amino acid Ser223Arg substitution was shown to recapitulate completely the unique catalytic properties of the 1.3.19 variant. These results can be explained by proposing that this mutation acts to "swap" the P(1) Arg side chain normally found in WT substrate peptides with the 223Arg side chain in the S(1) subsite of OmpT.