Parathyroid localization with high-resolution ultrasound and technetium Tc 99m sestamibi.

HYPOTHESIS: High-resolution ultrasound and technetium Tc 99m sestamibi scanning can be used for preoperative localization of abnormal parathyroid glands in patients with hyperparathyroidism. DESIGN: Ultrasound and sestamibi scanning were performed in patients undergoing neck exploration for hyperparathyroidism. If the 2 scans agreed in identifying a single adenoma, and surgery confirmed the location of a single adenoma and an ipsilateral normal gland, a unilateral exploration was performed. SETTING: University tertiary care center. PATIENTS: Sixty-one consecutive patients undergoing surgery for hyperparathyroidism from September 1, 1994, through September 30, 1997. INTERVENTIONS: High-resolution ultrasound was performed in 59 patients and sestamibi scanning in 58 patients; all patients underwent neck exploration by a single surgeon. MAIN OUTCOME MEASURES: The results of preoperative ultrasound and sestamibi scanning were compared with operative and histological findings. RESULTS: All patients were cured of hypercalcemia. Specificity of ultrasound and sestamibi scanning was 98% and 99%, respectively; however, their sensitivity was only 57% and 54%, respectively. Both imaging modalities had lower sensitivities in the setting of multigland disease. If both imaging studies were considered as a single test, sensitivity for imaging in patients with primary hyperparathyroidism reached 78%. Our localization protocol allowed a unilateral approach in 43% of patients (23 of 53). CONCLUSIONS: These results confirm the value of preoperative localization in patients with hyperparathyroidism. A unilateral approach can be used with a high degree of success in cases when ultrasound and sestamibi scanning agree in the identification of a single adenoma confirmed by surgical exploration with the identification of a normal ipsilateral gland.

Alternative or additional diagnoses on unenhanced helical computed tomography for suspected renal colic: experience with 1000 consecutive examinations.

OBJECTIVES: To determine the incidence and spectrum of significant alternative or additional diagnoses established or suggested on unenhanced helical computed tomography (CT) in a large series of patients with suspected renal colic. METHODS: One thousand consecutive unenhanced helical CT examinations were performed for suspected renal colic. All official CT reports were retrospectively reviewed, which was followed by review of all available relevant follow-up radiology reports. A selected image and chart review was also performed. RESULTS: Ureteral calculi were identified on 557 examinations, findings consistent with a recently passed stone were discovered on 67 examinations, and 275 CT examinations were unremarkable. An alternative or additional diagnosis was established or suggested on 101 examinations, including in 26 patients with concurrent ureteral calculi. There were 62 genitourinary and 39 nongenitourinary tract diagnoses. Eighty-seven of the diagnoses could be confirmed on retrospective image review combined with patient follow-up. There were two false-positive diagnoses for significant, alternative pathologic findings. CONCLUSIONS: A wide spectrum of significant, alternative, and additional genitourinary and nongenitourinary diagnoses can be reliably established or suggested on unenhanced helical CT performed for suspected renal colic. These abnormalities were identified in 10% of cases in this series of 1000 consecutive CT examinations.

The validity of self-reported hypertension and correlates of hypertension awareness among blacks and whites within the stroke belt.

Hypertension surveillance activities increasingly are relying on information obtained by self-report. However, limited information is available concerning the validity of such data, especially among populations residing within the stroke belt. We used interview information and blood pressure measurements from the South Carolina Cardiovascular Disease Prevention Project to determine the validity of self-reported hypertension and the correlates of hypertension awareness among 2,210 whites and 704 blacks who participated in the program in 1987. The sensitivity, specificity, positive predictive value, and negative predictive value of self-reported hypertension were 79%, 91%, 76%, and 93% among white women; 82%, 88%, 79%, and 89% among black women; 62%, 91%, 75%, and 85% among white men; and 72%, 89%, 78%, and 85% among black men, respectively. Groups with highest sensitivity included women, persons older than age 39 years, and those who had seen a physician for preventive care within the last year. Correlates of hypertension awareness included an older age, visit to a physician for preventive care, and a family history of high blood pressure. Among hypertensive blacks, overweight persons were substantially more likely than nonoverweight persons to be aware of their hypertension (odds ratio [OR] = 4.6, 95% confidence intervals [CI] = 1.9, 10.7 in black women and OR = 4.4, 95% CI = 1.0, 17.9 in black men). The validity of self-reported hypertension was relatively high in all race-sex groups. There is a need to increase hypertension awareness among hypertensive blacks who are not overweight.

Health promotion practices among physicians.

Personal belief concerning both the validity of health promotion and the physician's ability to influence patient behavior may affect how much effort a physician spends on health promotion strategies. We assessed these beliefs through a mail survey to physicians practicing in a predominantly rural southern state in 1987 (n = 83) and 1991 (n = 96). Response rates in both studies exceeded 75%. The instrument was obtained from similar studies conducted in Massachusetts in 1981 and Maryland in 1983. Between 1987 and 1991 we found slight improvements in the perceived importance of many health behaviors, but significant improvement was observed in the importance of reducing intake of dietary saturated fat (66% in 1987 to 80% in 1991; P < .05). Less than 10% of the physicians thought they could be "very successful" in modifying patients' behaviors. However, in 1991 physicians perceived that their ability to be "very successful" in helping patients to modify their behavior would increase threefold (8%-24% for exercise; 4%-18% for smoking) if given appropriate support. Although the type of appropriate support was not identified, the credibility of physician's advice in promoting health changes is important. These results suggest that efforts should be made to provide support to physicians who are inclined to discuss health behavior changes with their patients. Medical Subject Headings (MeSH): dietary fats, exercise, patient education, physician's practice patterns, smoking.

The association between alcohol use and health behaviors related to the risk of cardiovascular disease: the South Carolina Cardiovascular Disease Prevention Project.

OBJECTIVE: This study examines the relationship between alcohol use and health behaviors related to the risk of cardiovascular disease (CVD). In particular, we examined the relationship between alcohol use and leisure time physical activity, participation in community physical activity programs and behaviors used for weight loss. Numerous studies have found a "protective" effect of moderate alcohol consumption on the risk of CVD. However, most of these studies have not adequately controlled for potential confounding by health behaviors associated with alcohol use. METHOD: We used descriptive and logistic regression analyses to examine cross-sectional survey data from 2,072 participants in the South Carolina Cardiovascular Disease Prevention Project. RESULTS: After controlling for age, race, education and preexisting CVD, moderate and heavy drinkers who do not smoke were more likely than nondrinkers to report engaging in regular leisure time physical activity. The relationship between other health behaviors and alcohol consumption was less clear. Among men, moderate and heavy drinkers were no more likely than nondrinkers to participate in community physical activity programs; among women, moderate and heavy drinkers were more likely than nondrinkers to report this activity. Moderate drinkers were more likely than nondrinkers to report that they were attempting to lose weight, however this difference was not statistically significant. CONCLUSIONS: These data suggest that at least some of the apparent protective effect of moderate alcohol consumption found in other studies may be due to differences between nondrinkers and drinkers with respect to physical activity and other health practices.

Appendicitis and its mimickers.

Unenhanced helical CT is an accurate technique for the evaluation of patients with suspected acute appendicitis. This non-operator-dependent examination can be performed without the risk of intravenous contrast material or the delay associated with the use of oral and rectal contrast material. This article reviews the unenhanced helical CT findings of acute appendicitis and those entities that commonly mimic acute appendicitis clinically.

Unenhanced CT of abdominal and pelvic hemorrhage.

CT performed without oral or intravenous contrast is the initial imaging study of choice in many situations for the detection of hemorrhage anywhere in the abdomen and pelvis. The presence or absence of hemorrhage can be determined rapidly, and the amount and precise location of hemorrhage can also be evaluated. This article reviews the appearances and the common and unusual etiologies of abdominal and pelvic hemorrhage on unenhanced CT. The role of intravenous contrast-enhanced CT in patients with known or suspected abdominal and pelvic hemorrhage is also examined.

Diagnosis of pancreatic injury after blunt abdominal trauma.

Expeditious diagnosis and treatment of pancreatic injury continues to elude the trauma surgeon and radiologist. Missed or underestimated pancreatic injury is responsible for a high level of morbidity and mortality after blunt or penetrating trauma. Unfortunately, inappropriate therapy can lead to devastating consequences such as severe endocrine or exocrine insufficiency. Abdominal CT is currently the imaging method of choice for evaluating patients with blunt trauma. This article reviews the constellation of CT findings that the radiologist must rely on to establish the diagnosis of pancreatic injury.

Primary malignant pulmonary hemangiopericytoma.

A primary malignant pulmonary hemangiopericytoma was diagnosed in a 45-year-old woman who complained of 10 months of cough and exertional dyspnea. One year after resection of the mass, a metastatic lesion was removed from the contralateral lung. The literature on this unusual pulmonary lesion is reviewed.

Kinetics of hydrogen-deuterium exchange in guanosine 5'-monophosphate and guanosine 3':5'-monophosphate determined by laser-Raman spectroscopy.

Pseudo-first-order rate constants governing the deuterium exchange of 8-CH groups in guanosine 5'-monophosphate (5'-rGMP) and guanosine 3':5'-monophosphate (cGMP) were determined as a function of temperature in the range 30-80 degrees C by means of laser-Raman spectroscopy. For each guanine nucleotide the logarithm of the rate constant exhibits a strictly linear dependence on reciprocal temperature: i.e., k psi = Ae-Ea/RT with A = 8.84 X 10(14) h-1 and Ea = 24.6 kcal/mol for 5'-rGMP and A = 3.33 X 10(13) h-1 and Ea = 22.2 kcal/mol for cGMP. Exchange of the 8-CH groups in guanine nucleotides is generally 2-3 times more rapid than in adenine nucleotides [cf. g. j. thomas, Jr., & J. Livramento (1975) Biochemistry 14, 5210-5218]. As in the case of adenine nucleotides, cyclic and 5' nucleotides of guanine exchange at markedly different rates at lower temperatures, with exchange in the cyclic nucleotide being the more facile. Each of the guanine nucleotides was prepared in four different isotopic modifications for Raman spectral analysis. The Raman frequency shifts resulting from the various isotopic substitutions have been tabulated, and assignments have been given for most of the observed vibrational frequencies.

Non-contrast spiral CT for patients with suspected renal colic.

Renal colic, defined as acute flank pain caused by the passage of a ureteral calculus, is a common condition, but the correct diagnosis may not be apparent clinically. For decades, intravenous urography has been the test of choice for evaluating patients with suspected renal colic. Recently, unenhanced (non-contrast) helical CT has been shown to be an accurate and highly effective examination which can be used instead of intravenous urography. In this article, the technique is reviewed in detail, including its advantages and potential pitfalls.

Determination of equilibrium binding affinity of distamycin and netropsin to the synthetic deoxyoligonucleotide sequence d(GGTATACC)2 by quantitative DNase I footprinting.

A new method for determining the equilibrium binding constant of antitumor drugs to specific DNA sequences by quantitative DNase I footprinting is presented. The use of a short synthetic DNA oligomer to define a homogeneous population of DNA binding sites enables the calculation of the free drug concentration and the fraction of DNA sites complexed with drug in solution and is described for the first time. Since a 1:1 stoichiometry is observed for each drug-oligomer DNA complex, it becomes possible to calculate equilibrium binding constants in solution. By use of this technique, the binding affinities of the nonintercalating drugs netropsin and distamycin to the synthetic oligonucleotide d(GGTATACC)2 are determined to be Ka (25 degrees C) = 1.0 X 10(5) and 2.0 X 10(5) M-1, respectively. Quantitation of the temperature dependence associated with complex formation results in a determination of standard enthalpies of -3.75 and -8.48 kcal mol-1 for the binding of netropsin and distamycin, respectively. Calculation of other thermodynamic parameters are found to be in agreement with previous studies and indicate that the DNA binding process for these compounds is predominantly enthalpy driven. This method of quantitative DNase I footprinting is demonstrated to be a useful technique for the measurement of drug affinities to specific binding sites on DNA oligomers which are designed and synthesized expressly for this purpose. Applications of the technique to the determination of drug binding affinities at specific sites within native DNA sequences are discussed.

Sequence specificity of actinomycin D and Netropsin binding to pBR322 DNA analyzed by protection from DNase I.

A direct approach to determining the sequence specificities of equilibrium binding drugs by using the DNase protection technique is described. The method utilizes singly end-labeled restriction fragments and partial digestion of the drug fragment complex with DNase I. Microdensitometry of autoradiograms produced after electrophoretic separation of digestion products allows determination of sequences that are affected by drug binding. The feasibility of the technique for locating small ligands bound to DNA and its eventual use as a quantitative thermodynamic approach to studying ligand binding to heterogeneous DNA as a function of sequence is illustrated by using actinomycin D and Netropsin.

Gilvocarcin V exhibits both equilibrium DNA binding and UV light induced DNA adduct formation which is sequence context dependent.

The relative degree of both equilibrium binding and of ultraviolet light induced adduct formation for the antitumor antibiotic gilvocarin V with two hexaecamer DNA sequence isomers, d[ATATATAGCTATATAT]2 and d[AAAAAAAGCTTTTTTT]2, was assessed. The experiments reveal that gilvocarin V binds, under equilibrium conditions, and reacts, in the presence of exogenously applied UV light, more efficiently with the alternating purine:pyrimidine sequence hexadecamer than the homopurine:homopyrimidine duplex at identical gilvocarcin V to DNA duplex ratios. DNAse I digests of adduct containing duplexes derived from the d[AAAAAAAGCTTTTTTT]2 duplex, identified and isolated using gel shift assays employing denaturing polyacrylamide gels, confirm that gilvocarcin V adducts can be formed with thymine residues but suggest that adduct formation with either adenine or guanine residues is also possible.

Unenhanced helical CT of ureteral stones: incidence of associated urinary tract findings.

OBJECTIVE: The objective of this study was to determine the incidence of urinary tract findings associated with ureteral stones on unenhanced helical CT scans of patients with acute renal colic. MATERIALS AND METHODS: One hundred forty-one consecutive patients with suspected renal colic were referred by the emergency department for a helical CT scan that was obtained without oral or IV contrast. The CT scans of 54 of these patients were interpreted as positive for ureteral calculi, and these CT scans were reviewed retrospectively. The size and location of each ureteral calculus and of any concurrent urinary tract calculi were recorded. The presence or absence of hydronephrosis, hydroureter, perinephric edema or soft-tissue stranding, and periureteral edema was also noted. RESULTS: We reviewed the original 5-mm axial images from the 54 CT scans. Calculi were present in the proximal, mid, and distal ureter in eight, four, and 14 patients respectively, and at the ureterovesicular junction in 28 patients. Only two patients had more than one ureteral calculus, and none had a contralateral ureteral calculus. Concurrent renal parenchymal and/or nonobstructing calculi in the renal pelvis were seen in five patients with proximal, mid, or distal ureteral stones and in 16 patients with ureterovesicular junction stones. Hydronephrosis was found in 37 patients, hydroureter in 36 patients, and perinephric soft-tissue changes in 35 patients. Periureteral edema could not be evaluated in the 28 patients with ureterovesicular junction calculi because of the adjacent bladder, but periureteral edema was clearly seen immediately adjacent to the ureteral stone in 17 of the other 26 patients. Only two of the 54 patients had no evidence of hydronephrosis, hydroureter, or perinephric soft-tissue changes. CONCLUSION: In patients with ureteral calculi imaged with unenhanced CT for acute renal colic, associated findings included hydronephrosis, hydroureter, perinephric soft-tissue changes, and periureteral edema. These common findings provided supportive evidence that an acute obstructive process was present.

Actinomycin D facilitates transition of AT domains in molecules of sequence (AT)nAGCT(AT)n to a DNAse I detectable alternating structure.

The interaction of actinomycin D with (AT)nAGCT(AT)n (where n = 2, 3, or 4) was investigated using a combination of imino proton NMR and DNAse I digestion. The stoichiometry of the interaction appears to be one:one with the actinomycin chromophore intercalated between the two GC base pairs. This binding event facilitates the conversion of the flanking repetitive AT regions to an alternating conformation characterized by induced sensitivity of the ApT sequences to attack by DNAse I. The neighboring TpA sequences do not exhibit rate changes as a function of binding of the drug. The potential relevance of such ligand induced DNA structural alterations is discussed.

Spontaneous intramural small bowel haemorrhage: importance of non-contrast CT.

The purpose of this study was to evaluate the abdominal CT findings in patients with spontaneous intramural small bowel haemorrhage. We retrospectively reviewed the abdominal CT scans of six patients with known intramural small bowel haemorrhage. All of the patients had an underlying coagulopathy. All six patients underwent CT examinations without oral or intravenous contrast media. All six non-contrast CT scans showed hyperattenuation of the involved bowel segments, with thickened and dilated proximal small bowel. Therefore, patients who are clinically at risk for intramural small bowel haemorrhage should undergo a non-contrast CT scan of the abdomen prior to the routine oral and intravenous contrast-enhanced scan. In most cases the non-contrast scan will provide definitive diagnostic information which may not be evident from the contrast-enhanced scan alone.

Double-minute chromosomes as megabase cloning vehicles.

Radiation-reduced chromosomes provide valuable reagents for cloning and mapping genes, but they require multiple rounds of x-ray deletion mutagenesis to excise unwanted chromosomal DNA while maintaining physical attachment of the desired DNA to functional host centromere and telomere sequences. This requirement for chromosomal rearrangements can result in undesirable x-ray induced chromosome chimeras where multiple non-contiguous chromosomal fragments are fused. We have developed a cloning system for maintaining large donor subchromosomal fragments of mammalian DNA in the megabase size range as acentric chromosome fragments (double-minutes) in cultured mouse cells. This strategy relies on randomly inserted selectable markers for donor fragment maintenance. As a test case, we have cloned random segments of Chinese hamster ovary (CHO) chromosomal DNA in mouse EMT-6 cells. This was done by cotransfecting plasmids pZIPNeo and pSV2dhfr into DHFR-CHO cells followed by isolation of a Neo + DHFR + CHO donor colony and radiation-fusion-hybridization (RFH) to EMT-6 cells. We then selected for initial resistance to G418 and then to increasing levels of methotrexate (MTX). Southern analysis of pulsed-field gel electrophoresis of rare-cutting restriction endonuclease digestions of DNA from five RFH isolates indicated that all five contain at least 600 kb of unrearranged CHO DNA. In situ hybridization with the plasmids pZIPNeo and pSV2dhfr to metaphase chromosomes of MTX-resistant hybrid EMT-6 lines indicated that these markers reside on double-minute chromosomes.