mtDNA disease in the primary care setting.

Disorders of mitochondrial DNA (mtDNA) may commonly present to primary care physicians but go undiagnosed. A 36-year-old man with a 15-year history of psychosis, seizures, and sensorineural hearing loss and a family history of diabetes mellitus and heart disease presented to our hospital without a unifying diagnosis. Physiologic, biochemical, and genetic testing revealed deficient aerobic metabolism, a defect in mitochondrial electron transport, and the presence of an A-to-G point mutation at position 3243 of the mitochondrial leucine-transfer RNA gene, establishing the diagnosis of mitochondrial encephalopathy, lactic acidosis, and strokelike syndrome (MELAS). Diagnosing mtDNA disorders requires a careful integration of clinical signs and symptoms with pedigree analysis and multidisciplinary testing. Diagnosis is important to provide genetic counseling, avoid unnecessary evaluation, and facilitate therapy for symptomatic relief.

Conceptual and technical considerations when combining large data sets.

Secondary analysis provides a useful method for the development of new knowledge. Larger samples can be constructed, and secondary analysis can be enhanced when data sets are combined. A standardized method for combining large data sets is crucial, yet literature on methods for combining large data sets for secondary analysis is lacking. The purpose of this article is to outline and explain the process of combining two or more large data sets (n = 276, n = 125) for secondary analysis by using these authors' previous work with large oncology and AIDS caregiver data sets.

Issues to consider when choosing and using large national databases for research of families.

Secondary analysis of large national databases offers promise for research of families. In this article, issues that the secondary analyst must consider when choosing a database for research of families are described. Potential advantages and limitations of databases are discussed. Strategies to minimize potential limitations are highlighted.

Conceptual and pragmatic considerations in conducting a secondary analysis. An example from research of families.

In this article, the authors discuss conceptual and pragmatic considerations for conducting research of families using large secondary data sets. Conceptual considerations include establishing consistency among the theory, variables, and available data, and determining reliability and validity of the data in the context of the theory. Pragmatic considerations include the use of resources such as management of the data among several authors, criteria and methods for selection of a subsample, and, recoding of the data to examine dyadic difference scores. The Family Special Interest Group of the Eastern Nursing Research Society initiated this research as part of a project to analyze families using large national data sets. The purpose of the secondary analysis was to identify family beliefs about healt-promoting behaviors. Combining parent and teen data to create relational level data resulted in new information that had not been identified in the original survey.

Parent-teen worry about the teen contracting AIDS.

A secondary data analysis of the National Commission on Children: 1990 Survey of Parents and Children was conducted with a subsample of 457 parent-teen pairs who responded to the "worry about AIDS" question. The teen's worry about contracting AIDS was associated with race, parent's education, the amount of discipline from the parent for engaging in sex, the teen's desire to talk to the parent about the problem of sex, the teen's rating of the neighborhood as a safe place to grow up, whether the parent listened to the teen's telephone interview, and the parent's response to whether his or her teen had a history of sexually transmitted disease. Of the parent-teen pairs in the subsample, 46% (N = 210) agreed in their responses about worry. Agreement was more frequent among the parent-teen pairs when compared to randomly constructed surrogate pairs. Dyadic analysis supported a family system view of perceived susceptibility.

Desensitization of beta-adrenergic receptors in adipocytes causes increased insulin sensitivity of glucose transport.

To determine the effect of desensitization of adipocyte beta-adrenergic receptors on insulin sensitivity, rats were continuously infused with isoproterenol (50 or 100 micrograms.kg-1.h-1) for 3 days by osmotic minipumps. Epididymal adipocytes were isolated. The cells from treated animals were desensitized to isoproterenol, as determined by response of lipolysis (glycerol release). Binding of [125I]iodocyanopindolol was decreased by approximately 80% in adipocyte plasma membranes isolated from treated rats, indicating that beta-adrenergic receptors were downregulated. Cellular concentrations of Gn alpha and Gi alpha were not altered. Insulin sensitivity was determined by measuring the effect of insulin on glucose transport (2-deoxy-[3H]glucose uptake). Cells from the isoproterenol-infused rats were markedly more sensitive to insulin than those from control rats. This was evidenced by an approximately 50% increase in maximal glucose transport rate in cells from the high-dose isoproterenol-treated rats and by an approximately 40% decrease in the half-maximal effective concentration of insulin in both groups. 125I-labeled insulin binding to adipocytes was not altered by the isoproterenol infusions, indicating that desensitization of beta-adrenergic receptors results in tighter coupling between insulin receptors and stimulation of glucose transport.

Effect of energy compared with carbohydrate restriction on the lipolytic response to epinephrine.

Fasting enhances the lipolytic sensitivity of adipose tissue to beta-adrenergic stimulation. The importance of carbohydrate compared with total energy restriction in regulating the lipolytic response to epinephrine was evaluated. Five normal volunteers participated in two study protocols in a randomized cross-over design separated by a 3-wk period. In one study (total energy restriction) the subjects fasted for 84 h, whereas in the other (carbohydrate restriction) a lipid emulsion was infused for 12-15 h each day to meet resting energy requirements during an 84-h oral fast. Glycerol flux, an index of whole-body lipolysis, was measured by infusing [2H5]glycerol. Each subject was studied in the basal state and during a 1-h infusion of epinephrine (0.015 microgram kg(-1 min(-1) after 84 h of total energy restriction and after 84 h of carbohydrate restriction (12 h after the final lipid infusion). The lipolytic response to epinephrine, defined as the total area between the glycerol flux curve and baseline during 1 h of epinephrine infusion, was similar after total energy restriction (241 +/- 141 mumol/kg) and carbohydrate restriction (294 +/- 58 mumol/kg). We conclude that carbohydrate restriction, not total energy restriction, is responsible for the increase in lipolytic sensitivity observed during fasting.

Stereospecific synthesis of peptidyl alpha-keto amides as inhibitors of calpain.

Peptidyl alpha-keto amides have been synthesized and tested as inhibitors of the cysteine protease calpain. A stereospecific synthesis was devised in which Cbz-dipeptidyl-alpha-hydroxy amides were oxidized with TEMPO/hypochlorite to the corresponding alpha-keto amides. This oxidation was accomplished in good yields and without epimerization of the chiral center adjacent to the ketone. The potent inhibition of porcine calpain I by the L,L diastereomers, combined with the poor inhibition by the L,D diastereomers, established the requirement for the all-L stereochemistry of the active inhibitor. The early lead inhibitors were very hydrophobic and, therefore, poorly soluble in aqueous solutions. Using the stereospecific route, new compounds were prepared with polar groups at the C- and N-termini. These modifications resulted in more soluble inhibitors that were still potent inhibitors of calpain. Studies of the stability of these alpha-keto amides showed that absolute stereochemistry can be maintained in acidic and unbuffered environments but general base-catalyzed epimerization of the chiral center adjacent to the ketone occurred rapidly. The alpha-hydroxy precursors were inactive as inhibitors of calpain, which supports the hypothesis that the alpha-keto compounds reversibly form an enzyme-bound tetrahedral species that results from the nucleophilic addition of the catalytic thiol of calpain to the electrophilic ketone of the inhibitor.

Progressive alterations in lipid and glucose metabolism during short-term fasting in young adult men.

Stable isotope tracers and indirect calorimetry were used to evaluate the progressive alterations in lipid and glucose metabolism after 12, 18, 24, 30, 42, 54, and 72 h of fasting in six healthy male volunteers. The rates of appearance (Ra) of glycerol and palmitic acid in plasma doubled from 2.08 +/- 0.22 and 1.63 +/- 0.20 mumol.kg-1 x min-1, respectively, after 12 h to 4.36 +/- 0.36 and 3.26 +/- 0.40 mumol.kg-1 x min-1, respectively, after 72 h of fasting (P < 0.01). Of the total increase in lipid kinetics, 60% occurred between 12 and 24 h of fasting; the greatest interval change occurred between 18 and 24 h of fasting. Glucose Ra and plasma concentration decreased by approximately 25% between 12 h (11.0 +/- 0.4 mumol.kg-1 x min-1 and 5.58 +/- 0.08 mmol/l, respectively) and 72 h (8.3 +/- 0.3 mumol.kg-1 x min-1 and 4.14 +/- 0.10 mmol/l, respectively) of fasting (P < 0.01), but no statistically significant changes occurred between 18 and 24 h of fasting. Plasma insulin decreased by approximately 50% between 12 h (64.6 +/- 12.9 pmol/l) and 72 h (30.1 +/- 7.9 pmol/l) of fasting (P < 0.001). Of the total decline in plasma insulin, 70% occurred within the first 24 h of fasting. These results demonstrate that the mobilization of adipose tissue triglycerides increases markedly between 18 and 24 h of fasting in young adult men. The early alterations in lipid metabolism are associated with a decline in circulating insulin but do not seem to be regulated by changes in glucose kinetics or plasma glucose concentrations.

Angioscopy for intraoperative management of thromboembolectomy.

Our experience with angioscopy suggests that direct visualization of the arterial lumen during thromboembolectomy procedures would provide a more reliable method of assessing luminal morphologic characteristics than angiography alone. We inspected 32 grafts (seven aortobifemoral, 18 infrainguinal bypass, and seven dialysis access fistula grafts) in 32 patients. Thirty-one patients had thrombotic events and one patient had an acute embolus. Angioscopy following standard catheter thrombectomy revealed significant amounts of retained thrombus or neointima in all thrombectomies. Angioscopic information from 18 patients with an infrainguinal bypass graft led to graft revision in six cases and placement of a new graft in 10 cases. One graft limb was replaced in seven aortobifemoral grafts, and multiple repeated thrombectomies were employed to extract debris in the remaining six cases. Repeated graft thrombectomy was also beneficial in dialysis access fistulas. Angioscopy allowed us to omit the completion angiogram and led to an improved technical result. We conclude that angioscopy is useful during thromboembolectomy procedures.

Lipids and lipoproteins in a triethnic sample of 5- or 6-year-old Type A or Type B children.

The Type A behavior pattern (TABP) has been proposed as a risk factor for coronary heart disease (CHD). Several studies have indicated an association between Type A behavior and serum cholesterol levels. If the effects of TABP are mediated by conventional CHD risk factors, evidence for a causal relationship between TABP and CHD would be strengthened if associations were detected among the young. This paper addresses the following: (1) Do levels of serum lipids and lipoproteins among young children vary by ethnicity, gender, or TABP? (2) Can obtained differences be accounted for by possible confounding factors, such as SES or body composition? ANCOVA revealed no significant ethnic, gender, or TABP effects for total serum cholesterol or HDLc. Analyses of LDLc and triglycerides disclosed significant main effects for gender and for ethnicity. A Competition subscale by ethnicity interaction was the only effect to approach statistical significance for TABP. The strongest findings were a replication of differences in lipid and lipoprotein risk factors by ethnicity.

Comparison of contrast arteriography to arterial mapping with color-flow duplex imaging in the lower extremities.

Color flow duplex scanning was used to "map" the iliofemoral and femoral popliteal segments in 61 patients (84 extremities) undergoing evaluation for excimer laser angioplasty. Eight locations, iliac, common femoral, profunda femoris, proximal and distal superficial femoral artery, proximal and distal popliteal, and tibioperoneal trunk were scored as normal versus abnormal, greater than 50% stenosis, or occluded, and occlusions were measured in centimeters. Specificity, sensitivity, and accuracy were calculated with the arteriogram as the gold standard (83% and 96%, respectively, for normal vs abnormal, 87% and 99% for 50% stenosis, and 81% and 99% for occlusions). Color flow accurately identified the presence and extent of occlusions in 48 of 51 extremities (94%) when compared to arteriography plus operative findings, since arteriography alone tended to overestimate occlusion length. It is concluded that color flow Doppler alone may be used to screen patients with peripheral vascular disease to assess candidacy for endovascular procedures without antecedent arteriography, and that arteriography alone would exclude some patients from consideration by falsely overestimating occlusion lengths.

Plasma lipoproteins in cortical versus lacunar infarction.

We investigated the relation of plasma lipids to the risk for ischemic stroke by comparing clinical and biochemical characteristics of survivors of cortical (n = 48) and lacunar (n = 36) brain infarction. By analysis of variance, no differences were observed in the concentrations of total cholesterol, triglycerides, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, or apoproteins A1 and B. Patients with lacunar infarction, however, had higher concentrations of high density lipoprotein (HDL)-cholesterol than patients with cortical stroke. This HDL-cholesterol difference was due primarily to a strikingly low HDL-cholesterol content in white patients with cortical stroke. These data suggest that previously demonstrated differences in HDL-cholesterol concentrations between patients with ischemic stroke and control subjects without stroke may apply to patients with cortical but not lacunar infarction. Separation of cerebral infarction into subtypes based on mechanism may help clarify lipid-related risk factors in cerebrovascular disease.

Angioscopic visualization of blood vessel interior in animals and humans.

The purpose of this study is to describe the use of angioscopes in flowing bloodstreams of animals and humans, to demonstrate the ability to precisely deliver laser energy to an intravascular target using visual guidance and to determine the information content and spatial content of angioscopy. Angioscopy was performed in 5 living dogs, 16 cadaver vascular segments, and 14 patients at the time of peripheral or coronary bypass surgery. Five canine femoral artery segments received angioscopically directed intravascular Nd:YAG laser irradiation. We were able to precisely direct the laser irradiation to predetermined intimal targets. Gross tissue injury varied from none to carbonization and vascular perforation, depending on incident energy. Using a variety of flexible fiberoptic endoscopes ranging in diameter from 1.5 to 3.7 mm, we were able to visualize intravascular structures including plaque, suture lines, venous valves, and thrombi in living patients. No patient incurred complications of any sort. We conclude that angioscopy using flexible endoscopes can be performed safely, can provide clinically useful information, and may provide a means for delivering visually directed intravascular laser irradiation.

Primary metastasizing aortic endothelioma.

An instance of malignant endothelioma, primary in the aorta, metastasizing to intestine and bone, is reported. The aortic tumor was successfully resected. The unexpected finding of a large hepatic growth at autopsy raised the possibility that the aortic neoplasm was a metastasis. Histochemical, immunologic, and ultrastructural studies supported the diagnosis of an endothelial neoplasm. Although a number of malignant aortic and large vessel tumors have been reported, only four previous instances appear to be endotheliomatous.

Insulin-like effects of fatty acid synthesis in liver of hamsters infected with plerocercoids of the tapeworm, Spirometra mansonoides.

Elevated serum lipids are associated with infections of laboratory rodents with plerocercoids of Spirometra mansonoides. The effect of infection with these larval tapeworms on triglyceride degradation and hepatic de novo fatty acid synthesis was investigated in Syrian hamsters. Serum lipoprotein electrophoresis revealed a consistent elevation in very low density lipoproteins in the infected animals. Lipoprotein lipase activity was enhanced in the infected animals. After seven days of plerocercoid infection the activity of acetyl-CoA carboxylase (E.C. 6.4.1.2) was significantly elevated after 6, 12 and 18 hours of fasting. Fatty acid synthetase was significantly increased after 0, 6, 12, 18 and 24 hours of fasting. Therefore, a chronic insulin-like activity on lipid metabolism of hamsters is associated with plerocercoid infection.

Lipoprotein separation and low density lipoprotein molecular weight determination using high performance gel-filtration chromatography.

Plasma lipoproteins were isolated at d less than 1.225 g/ml from nonhuman primates of three species, cynomolgus, rhesus, and African green (vervet) monkeys. Individual lipoprotein classes were separated by high performance gelfiltration chromatography and low density lipoprotein (LDL) molecular weight was determined. A comparison was made using column configurations including TSK 3000 SW, 4000 SW, and 5000 PW columns. Due to its relative simplicity, stability, and economy, a single 5000 PW column was selected for most of the work. The recovery of lipoprotein cholesterol from the column averaged 91 +/- 2.5%. A comparison of the immunologic, chemical, and electrophoretic properties of high density lipoproteins (HDL) and LDL isolated by this technique with those of HDL and LDL isolated by conventional agarose column chromatography indicated that lipoproteins isolated by high performance gel-filtration chromatography were intact and reasonably free of cross contamination. A standard preparation of 125I-labeled LDL was added to the d less than 1.225 g/ml lipoprotein fraction just prior to separation and a relative size index, r1, was determined. When r1 values for a large number of samples were compared with the log of the LDL molecular weight (determined by agarose column chromatography) a linear relationship was found with a correlation coefficient, r = 0.85. The regression equation for this relationship could be used to calculate LDL molecular weights from the r1 value. These values agreed with LDL molecular weight determined by flotation equilibrium analysis in the analytical ultracentrifuge. We conclude that high performance gel-filtration chromatography using the TSK 5000 PW column provides an analytical and preparative technique for simultaneous separation of individual lipoproteins and determination of LDL molecular weight.

Evaluation of a high-performance liquid chromatography method for isolation and quantitation of cholesterol and cholesteryl esters.

A rapid method for the separation and quantitation of unesterified cholesterol and cholesteryl esters by high-performance liquid chromatography is described. All of the cholesteryl esters typically present in plasma were resolved on Zorbax ODS reversed-phase columns using a linear gradient of water (3%-0%) in acetonitrile-tetrahydrofuran 65:35 (v/v) as eluting solvent. Results obtained by this method show good agreement with chemical and gas-liquid chromatographic methods for quantitation of cholesterol and determination of cholesteryl ester percentage compositions. High-performance liquid chromatography provides the only available method for the separation and quantitation of individual cholesteryl esters from lipid extracts of biological samples.