Randomized, single-blinded comparative study of the efficacy of amoxicillin (40 mg/kg/day) versus standard-dose penicillin V in the treatment of group A streptococcal pharyngitis in children

A 10-day course of amoxicillin at a dosage of 40 mg per kilogram per day was compared with conventional (lower dosage) penicillin V therapy in the treatment of culture-proven Group A streptococcal pharyngitis in children 3 to 18 years of age in a prospective, randomized, and single-blinded study. Children had to have signs and symptoms compatible with the diagnosis of streptococcal pharyngitis and to have a throat swab positive for Group A streptococci. A second throat culture was obtained 10 to 14 days after the completion of therapy. Serotyping was performed to help differentiate carrier states from reinfections. Of 161 children enrolled, 113 were evaluable; 55 received penicillin and 58 received amoxicillin. At the completion of therapy 70.9% (39/55) of patients in the penicillin group vs 87.9% (51/58) of patients in the amoxicillin group were asymptomatic (clinical cure, P = 0.025). At the completion of therapy, 54.5% (30/55) of patients in the penicillin group vs 79.3% (46/58) of patients in the amoxicillin group had negative throat cultures (bacteriologic cure, P = 0.005). The carrier rate (children who were well but who were still carrying the same serotype of Group A streptococcus) also differed between the groups: 13 (23.6%) in the penicillin group compared with six (10.3%) in the amoxicillin group. Amoxicillin at 40 mg/kg/day was significantly more effective than lower dosages of penicillin V for clinical and bacteriologic cure in the treatment of Group A streptococcal pharyngitis in children. The current perception that penicillin is declining in effectiveness may be due to inadequate dosing.

Influence of cholesterol screening and nutritional counseling in reducing cholesterol levels in children. The American Heart Association

The purpose of this study was to determine whether cholesterol screening and nutritional counseling can reduce cholesterol concentrations in populations of otherwise unrecognized hypercholesterolemic children. A large pediatric practice in Parma Heights, Ohio, has conducted cholesterol surveillance of children over 2 years of age since 1986. The importance of cholesterol and other recognized risk factors for the progression of atherosclerosis is discussed with all families, and the American Heart Association's Step-One diet is recommended. The present study examines data from a cohort of 894 children (473 boys, 421 girls) who had cholesterol concentrations above 185 mg/dL (4.79 mmol/L) (the 90th percentile) at baseline and, after counseling, had a repeat measurement an average of 2.2 years later. Their mean ages were 7 years at the first testing and 9.2 years at the second. Children who had cholesterol concentrations above 200 mg/dL (5.18 mmol/L) (the 95th percentile) had lipoprotein profiles done, and if their LDL cholesterol exceeded 130 mg/dL (3.37 mmol/L) (the 95th percentile), they were referred to a nutritionist, and family members were advised to have their blood lipids analyzed. Mean cholesterol concentration for all 894 children over this time period decreased by 9.4% (19.5 mg/dL [0.51 mmol/L]; 95% CI = 17.5 mg/dL [0.45 mmol/L] to 21.5 mg/dL [0.56 mmol/L]; P < 0.001). A similar decrease of 8.6% (16.6 mg/dL [0.43 mmol/L); 95% CI = 14.0 mg/dL [0.36 mmol/L] to 19.3 mg/dL [0.50 mmol/L); P < 0.001) was observed for the 463 children who had initial cholesterol concentrations between 185 and 200 mg/dL (4.79 and 5.18 mmol/L) and who therefore received a less intense intervention. Cholesterol concentrations in groups of otherwise unidentified hypercholesterolemic children can be significantly reduced as a result of cholesterol screening and nutritional counseling in a pediatric practice setting.

Elderly veterans receiving care at a Veterans Affairs Medical Center while enrolled in Medicare-financed HMOs. Is the taxpayer paying twice?

Elderly veterans who visit our Veterans Affairs (VA) Medical Center primary care clinic often mention they are enrolled in HMOs. Approximately 20% of patients hospitalized at our facility report health insurance coverage. Of 1,000 hospitalizations during a 6-month period in which veterans reported insurance coverage, 337 involved elderly veterans. Of these 337 hospitalizations, 218 (65%) were for 174 veterans who stated they were enrolled in a Medicare-financed HMO. The VA's Medical Care Cost Recovery Program deemed only 46 (21%) of the hospitalizations billable and received reimbursement for 20 (9%). Thus, the VA is providing costly services already paid for by the Health Care Financing Administration under prepaid capitation contracts, and recovers minimal reimbursement from the HMOs.

Effect of inspiratory training on mitochondrial DNA and cytochrome-c oxidase expression in the diaphragm

We have previously shown that respiratory training with inspiratory flow-resistive (IFR) loads improves diaphragm performance and is associated with an increase in cytochrome-c oxidase (COX) activity (1). The present study was conducted to define the level at which the increase in COX activity is controlled. Six sheep were trained with IFR loads for 3 h/day for 3 wk. The diaphragm was sampled from the six trained sheep and from six control sheep. Quantitative DNA and RNA slot-blot analyses with mitochondrially coded COX subunit III and nuclearly coded subunit IV probes and immunoblotting with anti-COX holoenzyme antibodies were performed. We found that in the diaphragm the amount of COX subunit proteins coded in either genetic system was greater in the trained than in the control sheep. Neither the amount of mitochondrial DNA nor mRNA for COX subunits was different between the two groups. We conclude that the increase in COX activity in the diaphragm after chronic respiratory training is determined by the amount of subunit proteins, possibly involving translation/degradation of these proteins.

Mouse rhodanese gene (Tst): cDNA cloning, sequencing, and recombinant protein expression

Rhodanese (thiosulfate sulfurtransferase) is expressed at high levels in liver and is involved in the detoxification of cyanide. The full-length cDNA corresponding to the mouse rhodanese gene (Tst), which is located on chromosome 15, was cloned by PCR amplification of a liver cDNA library and subjected to DNA sequencing. Alignment of the rhodanese cDNA sequences from mouse and rat, which we previously cloned (Biochem. J. 275:227-231), revealed 97.3 percent identity at the protein level and 94.6 percent identity at the DNA level. When the mouse and rat cDNAs were expressed under the control of IPTG-inducible promoters in E. coli, the cell extracts exhibited cyanide-metabolizing activity, indicating that both genes encode functional rhodanese molecules.

Effect of chronic respiratory loading on the subunit composition of cytochrome c oxidase in the diaphragm

To elucidate in the diaphragm, 1) whether chronic inspiratory loading increases the amount of cytochrome c oxidase (COX) subunit proteins, and 2) how well the regulation of mitochondrially and nuclearly coded COX subunits is coordinated, we have trained six adult sheep with inspiratory flow-resistive loads for 3 h/day for 3 wk. Six other sheep served as controls. Proteins from crude muscle homogenates were separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotted, and reacted with polyclonal rabbit anti-bovine COX antibodies. A mitochondrially coded subunit (II) and nuclearly coded subunits (IV and VII) reacted with anti-COX antibodies and were quantified with laser densitometry using purified COX as a standard. In the costal diaphragm and for the equivalent amount of muscle homogenate protein, the integrated optical densities (IOD) for subunits II, IV, and VII were significantly greater in the trained sheep than in the controls. Similarly, the IOD for subunits II and VII were significantly greater in the trained than in the controls in the crural diaphragm. There were no differences between the two groups in the quadriceps, a muscle that was used as an untrained, internal control muscle. The ratios of the IOD for each of the two nuclearly coded subunits to that for mitochondrially coded subunit II were not different between the two groups. These data suggest that chronic inspiratory loading increases both mitochondrially and nuclearly coded COX subunits in the diaphragm and that the subunits coded by the two genetic systems are coordinately regulated.

The origin of HIV-1 isolate HTLV-IIIB

The striking similarity between the first two human immunodeficiency virus type 1 (HIV-1) isolates Lai/LAV (formerly LAV, isolated at the Pasteur Institute) and Lai/IIIB (formerly HTLV-IIIB, reported to be isolated from a pooled culture at the Laboratory of Tumor Cell Biology (LTCB) of the National Cancer Institute) provoked considerable controversy in light of the high level of variability found among subsequent HIV-1 isolates. In November 1990, the Office of Scientific Integrity at the National Institutes of Health commissioned our group to analyse archival samples established at the Pasteur Institute and LTCB between 1983 and 1985. Retrospective analyses have shown that contamination of a culture derived from patient BRU by one from patient LAI was responsible for the provenance of HIV-1 Lai/LAV; the contaminated culture (M2T-/B) was sent to LTCB in September 1983. Our goals were to determine which HIV-1 variants were present in the samples and the sequence diversity among HIV-1 isolates from the earliest stages of the AIDS epidemic. We examined archival specimens and report here the detection of six novel HIV-1 sequences in the cultures used to establish the pool: none is closely related to HIV-1 Lai/IIIB. A sample derived from patient LAI contained variants of both HIV-1 Lai/IIIB and HIV-1 Lai/LAV, and a sequence identical to a variant of HIV-1 Lai/IIIB was detected in the contaminated M2T-/B culture. We conclude that the pool, and probably another LTCB culture, MoV, were contaminated between October 1983 and early 1984 by variants of HIV-1 Lai from the M2T-/B culture. Therefore, the origin of the HIV-1 Lai/IIIB isolate also was patient LAI.

Plasma lipoprotein cholesterol concentrations in the golden-mantled ground squirrel (Spermophilus lateralis): a comparison between pre-hibernators and hibernators

1. The concentrations of total cholesterol (free cholesterol plus cholesteryl ester) in the plasma and in two lipoprotein fractions of golden-mantled ground squirrels (Spermophilus lateralis) were measured during pre-hibernation and compared to those values measured during hibernation. 2. Hibernating ground squirrels had significantly higher (P less than 0.005) very low density lipoprotein plus low density lipoprotein cholesterol (VLDL + LDL-C) concentrations than did pre-hibernating ground squirrels. 3. Hibernating squirrels additionally exhibited significantly higher (P less than 0.005) total plasma cholesterol concentration per high density lipoprotein cholesterol concentration (TPC/HDL-C) ratios than did pre-hibernating squirrels. 4. The significant differences in the lipoprotein cholesterol concentrations observed in this study suggest that lipoprotein metabolism in pre-hibernators was significantly different from that in hibernators and was a reflection of the marked biochemical and physiological adjustments these animals must undergo during their transition from pre-hibernation to hibernation.

Lipoprotein profiles in hypercholesterolemic children

Atherosclerosis is a process that begins in early life. Coronary heart disease is the result of complex interactions among a variety of risk factors of which hypercholesterolemia is but one. During routine screening, 500 children were identified with total cholesterol levels above the 95th percentile of 5.2 mmol/L (200 mg/dL). Lipoprotein profiles were then performed to confirm and delineate their lipid abnormalities. A definable lipid disorder was present in 85% of such children. Abnormal lipoprotein patterns included 292 children with type IIa, 99 with type IIb, and 25 with type IV phenotypes. An abnormally low high-density lipoprotein cholesterol level of less than 0.9 mmol/L (35 mg/dL) was observed in 20 children. Only 5% of patients were identified as being hypercholesterolemic because they had high-density lipoprotein cholesterol levels above the 95th percentile of 1.8 mmol/L (70 mg/dL). Thirty-two percent of children with total cholesterol levels above 5.2 mmol/L had a family member (sibling, parent, uncle, aunt, or grandparent) with a myocardial infarction prior to 55 years of age. Data from this study support universal cholesterol testing after 3 years of age and lipoprotein profiles for those with levels above 5.2 mmol/L.

Circulating lipoprotein cholesterol concentrations in the summer-active ground squirrel (Spermophilus lateralis): a comparison with those in humans and rabbits

1. The concentrations of total cholesterol (free cholesterol plus cholesteryl ester) in the sera and in two lipoprotein fractions of golden-mantled ground squirrels (Spermophilus lateralis) were measured and compared to those found in humans and New Zealand White rabbits (Oryctolagus cuniculus). 2. Squirrels showed significantly higher concentrations of total serum cholesterol (TSC; P less than 0.0005), high density lipoprotein cholesterol (HDL-C; P less than 0.0005), and very low density plus low density lipoprotein cholesterol (VLDL + LDL-C; P less than 0.0005) than those in rabbits. 3. Squirrels had significantly higher TSC (P less than 0.0005) and HDL-C (P less than 0.0005) concentrations than did humans. 4. Squirrels additionally exhibited significantly lower TSC/HDL-C ratios than did rabbits (P less than 0.005) or humans (P less than 0.0005). 5. The significant differences in lipoprotein metabolism observed in this study between the active hibernator and non-hibernators, may reflect the marked biochemical and physiological adjustments hibernating species make throughout their circannual cycle.

Implications of childhood hypercholesterolemia

Several studies have documented that hypercholesterolemia is common in American children. Other studies have shown that elevated cholesterol levels in childhood remain elevated well into adult life. Autopsy studies of adolescents have also found a strong positive correlation between antemortem cholesterol levels and early atherosclerotic changes in their aortas and coronary arteries. Collectively, these studies provide strong and consistent evidence that atherosclerosis begins in childhood. The evidence is also overwhelming that lowering elevated low density lipoprotein cholesterol levels reduces the risk of heart attacks caused by coronary heart disease, at least among middle-aged men. As a result, routine cholesterol and coronary heart disease risk factor surveillance in childhood is both productive and appropriate. Premature coronary heart disease may be largely preventable and atherosclerosis, if not preventable, can be significantly delayed.

Routine cholesterol surveillance in childhood

Coronary heart disease is the leading cause of death in the United States, and there is reason to believe that it begins in childhood. Evidence is accumulating that early diagnosis and treatment of hypercholesterolemia, a major coronary risk factor, can markedly reduce the incidence of atherosclerotic heart disease in later life. A pediatric group practice consisting of six pediatricians and a pediatric nurse practitioner performed a cholesterol surveillance study of 6500 children between 3 and 18 years of age. Parents and patients were counseled regarding other coronary risk factors, and the American Heart Association diet was recommended. According to the results of the study, 1251 children (19%) exceeded the acceptable 90th percentile for cholesterol and that 143 of 299 significantly hypercholesterolemic children (48%) had no family history of premature myocardial infarction or known hypercholesterolemia. The current recommendation is that only those children from high-risk families should be screened for an elevated cholesterol level. The authors conclude, as a result of this study, that all children older than 3 years of age should have a cholesterol test and that advice regarding avoidance of high-risk coronary life-style behaviors should be a routine part of pediatric anticipatory guidance.

Preparation of human cord sera for enzymatic triglyceride assays: removal of free glycerol by ultrafiltration

Enzymatic triglyceride assays that generate glycerol from triglycerides as a part of the enzymatic process in quantitating serum triglyceride levels give elevated values when external free glycerol is present. Our objective was to develop an ultrafiltration technique that would remove exogenous and/or endogenous free glycerol from small aliquots of human cord sera so that accurate serum triglyceride values could be obtained with the commercially available triglyceride assay kits. Exogenous glycerol was completely removed from cord sera when the samples were washed twice with saline in Amicon Centricon-30 microconcentrators. This ultrafiltration technique lowered cord serum triglyceride levels significantly (P less than 0.001), but had no effect on cord total serum cholesterol levels. A comparison of washed and unwashed cord sera by either polyacrylamide or agarose gel electrophoresis indicated that the serum protein and lipoprotein profiles were not altered by the ultrafiltration process.

Effect of dietary cholesterol on apolipoprotein E synthesis in the rabbit

Female New Zealand White rabbits were fed either rabbit chow or rabbit chow plus 1% (w/w) cholesterol for 14 days. The chow-fed rabbits had normal plasma lipoprotein profiles on agarose gel electrophoresis, 59 +/- 5 mg of cholesterol and 5.5 +/- 0.4 mg of apolipoprotein E (apoE) per dl of serum. The cholesterol-fed rabbits had significant amounts of beta-VLDL in their serum, 1870 +/- 140 mg of cholesterol and 96 +/- 12 mg of apoE per dl of serum. Relative rates of apoE synthesis were determined by incubating hepatocytes in culture medium containing [3H]leucine for 15 min at 37 degrees C and expressing the radioactivity incorporated into immunoprecipitable apoE as a percentage of the radioactivity incorporated into total protein. Hepatocytes from cholesterol-fed rabbits had twice the relative rate of apoE synthesis (1.05 +/- 0.18%) of hepatocytes from chow-fed rabbits (0.55 +/- 0.07%). This increase in synthesis could be a major contributor to the 17-fold increase in serum apoE levels in the cholesterol-fed rabbit.

Quantitation of apolipoprotein E in rabbit sera with a competitive enzyme-linked immunosorbent assay

A competitive enzyme-linked immunosorbent assay was developed to quantitate apoE levels in normal and cholesterolemic rabbit serum. The assay can detect 1 ng of apoE and has an interassay coefficient of variation of 5.1%. The assay's antigen specificity was established by the generation of a competitive displacement curve with rabbit apoE, but not with rabbit albumin nor with rabbit apoC. Nonimmune serum was not able to produce a detectable response in the assay. Lipid-protein interactions did not interfere with the assay and color development was linear throughout the incubation time. Rabbits fed a normal diet had 5.3 +/- 0.4 mg of apoE/dl serum. Rabbits fed a diet containing 1% (w/w) cholesterol for 14 days had 86 +/- 11 mg of apoE/dl serum.

Inhibition of steryl glycoside biosynthesis by acyl coenzyme a and by digitonin

ATP, GTP, CoA, Mg(2+), and Mn(2+) did not inhibit biosynthesis of steryl glycoside and acylated steryl glycoside when added singly to enzyme preparations from spinach leaves. The combination of ATP (but not GTP), CoA, and Mg(2+) or Mn(2+) caused marked inhibition, especially of steryl glycoside biosynthesis, when reaction mixture concentrations of the additions were 0.2 millimolar. Inhibition was attributed to acyl-CoA and could be reproduced by palmitoyl-CoA. The inhibition could be partially prevented by bovine serum albumin. The effects of palmitoyl-CoA were distinct at 10 micromolar, and 50% inhibition of biosynthesis was observed at 40 micromolar.Digitonin (0.6 millimolar) stopped steryl glycoside biosynthesis but permitted the conversion of steryl glycoside to acylated steryl glycoside, thus eliminating the possibility that acylated steryl glycoside is formed from sterol + an acyl-glucose donor.

Identification of an acyl donor in steryl ester biosynthesis by enzyme preparations from spinach leaves

A pathway for steryl ester biosynthesis in acetone powder preparations from spinach (Spinacia oleracea L.) leaves has been elucidated; free sterol and 1,2-diglyceride were the substrates. Although animals synthesize cholesteryl esters by three distinct biosynthetic pathways, none of these pathways utilizes 1,2-diglyceride as an acyl donor. Phosphatidylcholine, phosphatidic acid, triglyceride, 1,3-diglyceride, 1-monoglyceride, free fatty acid, and fatty acyl-CoA were not acyl donors for spinach leaf steryl ester biosynthesis in our assay system. The unstable 2 isomer of monoglyceride was not tested. It is possible that 1,2-diglyceride and 2-monoglyceride were both acyl donors for spinach leaf steryl ester biosynthesis. Acyl-labeled phosphatidylcholine and acyl-labeled phosphatidylethanolamine were rapidly degraded by acetone powder preparations to 1,2-diglyceride via phosphatidic acid. The 1,2-diglycerides were slowly metabolized to monoglycerides, triglycerides, free fatty acids, and steryl esters. The monoglycerides were rapidly degraded to free fatty acids and glycerol.

Subcellular distribution of steryl ester biosynthesis in spinach leaves

Higher steryl ester biosynthetic activities were obtained with Triton X-100-phosphatidylcholine-cholesterol mixed micelles than with Tween 80-phosphatidylcholine-cholesterol mixed micelles when incubated with spinach leaf (Spinacia oleracea L.) acetone powder preparations. The best incorporation of [4-(14)C]cholesterol into [4-(14)C]cholesteryl ester was obtained with a Triton X-100-phosphatidylcholine-cholesterol (10:1:1, w/w) mixed micelle system. This mixed micelle system, however, required 1,2-dipalmitin and fatty acid-free bovine albumin for optimal activity. The reaction exhibited a diglyceride specificity since the dipalmitin requirement could be replaced with neither 1-monopalmitin nor tripalmitin. Significant amounts of steryl ester biosynthetic activity were detected in the chloroplast (1,000g pellet), mitochondrial (3,000g pellet), and microsomal (20,000g and 88,000g pellet) fractions. Little activity was detected in the water-soluble (88,000g supernatant) fraction. The highest specific activity occurred in the 88,000g pellet. The 88,000g supernatant contained a heatstable, water-soluble substance that was required for optimal steryl ester biosynthesis in all of the pellet fractions. This factor was not lost during extensive dialysis but was destroyed by ashing, indicating that it was large and organic. Silver nitrate thin layer chromatography indicated that 60% of the biosynthesized steryl esters contained saturated fatty acids in the absence of 1,2-dipalmitin and that 83% contained saturated fatty acids in the presence of 1,2-dipalmitin.

Partial characterization of steryl ester biosynthesis in spinach leaves

Acetone powders of a 20,000g pellet fraction from spinach leaves (Spinacia oleracea L.) synthesized [4-(14)C]cholesteryl esters when incubated with [4-(14)C]cholesterol. The reaction was inhibited by digitonin. There was a reciprocal relationship between the decline of label in cholesterol and its incorporation into cholesteryl ester, indicating that free cholesterol was the direct precursor for cholesteryl ester biosynthesis. The hydrolysis of cholesteryl [1-(14)C]palmitate into free cholesterol and [1-(14)C]palmitate was not detected in these acetone powder preparations. Exogenous cholesteryl palmitate had no effect on the esterification of [4-(14)C]cholesterol. The data indicate that an esterase-type mechanism was not involved in the biosynthesis of these steryl esters. Label from [1-(14)C]palmitoyl-CoA was incorporated into steryl esters when incubated with spinach leaf acetone powder preparations. The optimal buffer for steryl ester biosynthesis was 2-(N-morpholino)ethanesulfonate and the optimal pH was 6. Iodoacetamide, N-ethylmaleimide, and dithiothreitol had no effect on the esterification reaction. Ethylenediaminetetraacetate, MgCl(2), CaCl(2), MnCl(2), and ZnSO(4) inhibited at concentrations of 10 to 30 mm.