Heart rate and respiratory rate in predicting risk of serious bacterial infection in febrile children given antipyretics: prospective observational study

Clinical algorithms used in the assessment of febrile children in the Paediatric Emergency Departments are commonly based on threshold values for vital signs, which in children with fever are often outside the normal range. Our aim was to assess the diagnostic value of heart and respiratory rate for serious bacterial infection (SBI) in children after temperature lowering following administration of antipyretics. A prospective cohort of children presenting with fever between June 2014 and March 2015 at the Paediatric Emergency Department of a large teaching hospital in London, UK, was performed. Seven hundred forty children aged 1 month-16 years presenting with a fever and ≥ 1 warning signs of SBI given antipyretics were included. Tachycardia or tachypnoea were defined by different threshold values: (a) APLS threshold values, (b) age-specific and temperature-adjusted centiles charts and (c) relative difference in z-score. SBI was defined by a composite reference standard (cultures from a sterile site, microbiology and virology results, radiological abnormalities, expert panel). Persistent tachypnoea after body temperature lowering was an important predictor of SBI (OR 1.92, 95% CI 1.15, 3.30). This effect was only observed for pneumonia but not other SBIs. Threshold values for tachypnoea > 97th centile at repeat measurement achieved high specificity (0.95 (0.93, 0.96)) and positive likelihood ratios (LR + 3.25 (1.73, 6.11)) and may be useful for ruling in SBI, specifically pneumonia. Persistent tachycardia was not an independent predictor of SBI and had limited value as a diagnostic test.  Conclusion: Among children given antipyretics, tachypnoea at repeat measurement had some value in predicting SBI and was useful to rule in pneumonia. The diagnostic value of tachycardia was poor. Overreliance on heart rate as a diagnostic feature following body temperature lowering may not be justified to facilitate safe discharge. What is Known: • Abnormal vital signs at triage have limited value as a diagnostic test to identify children with SBI, and fever alters the specificity of commonly used threshold values for vital signs. • The observed temperature response after antipyretics is not a clinically useful indicator to differentiate the cause of febrile illness. What is New: • Persistent tachycardia following reduction in body temperature was not associated with an increased risk of SBI and of poor value as a diagnostic test, whilst persistent tachypnoea may indicate the presence of pneumonia.

Management of Children With Fever at Risk for Pediatric Sepsis: A Prospective Study in Pediatric Emergency Care

Objective: To study warning signs of serious infections in febrile children presenting to PED, ascertain their risk of having sepsis, and evaluate their management. Design: Prospective observational study. Setting: A single pediatric emergency department (PED). Participants: Febrile children, aged 1 month-16 years, with >= 1 warning signs of sepsis. Interventions and Main outcome measures: Clinical characteristics, including different thresholds for tachycardia and tachypnoea, and their association with (1) delivery of pediatric sepsis 6 (PS6) interventions, (2) final diagnosis of invasive bacterial infection (IBI), (3) the risk for pediatric intensive care unit (PICU) admission, and (4) death. Results: Forty-one percent of 5,156 febrile children had warning signs of sepsis. 1,606 (34%) children had tachypnoea and 1,907 (39%) children had tachycardia when using APLS threshold values. Using the NICE sepsis guidelines thresholds resulted in 1,512 (32%) children having tachypnoea (kappa 0.56) and 2,769 (57%) children having tachycardia (kappa 0.66). Of 1,628 PED visits spanning 1,551 disease episodes, six children (0.4%) had IBI, with one death (0.06%), corresponding with 256 children requiring escalation of care according to sepsis guideline recommendations for each child with IBI. There were five additional PICU admissions (0.4%). 121 (7%) had intravenous antibiotics in PED; 39 children (2%) had an intravenous fluid bolus, inotrope drugs were started in one child. 440 children (27%) were reviewed by a senior clinician. In 4/11 children with IBI or PICU admission or death, PS6 interventions were delivered within 60 min after arriving. 1,062 (65%) visits had no PS6 interventions. Diagnostic performance of vital signs or sepsis criteria for predicting serious illness yielded a large proportion of false positives. Lactataemia was not associated with giving iv fluid boluses (p = 0.19) or presence of serious bacterial infections (p = 0.128). Conclusion: Many febrile children (41%) present with warning signs for sepsis, with only few of them undergoing investigations or treatment for true sepsis. Children with positive isolates in blood or CSF culture presented in a heterogeneous manner, with varying levels of urgency and severity of illness. Delivery of sepsis care can be improved in only a minority of children with IBI or admitted to PICU.

The genome of black cottonwood, Populus trichocarpa (Torr. & Gray)

We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.

Reliability and validity of the NIDDK-QA instrument in the assessment of quality of life in ambulatory patients with cholestatic liver disease

The NIDDK-QA instrument, developed and widely used in liver transplant recipients, assesses quality of life (QOL) in four domains, including liver disease symptoms, physical function, health satisfaction, and overall well-being. We investigated whether the instrument may be used as a disease-specific instrument in ambulatory patients with cholestatic liver disease. The NIDDK-QA instrument was administered in 96 patients with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) seen at the Mayo Clinic. The SF-36, a well-established generic instrument, was also administered. Standard measures for test-retest reliability, internal consistency, and discriminant and concurrent validity were examined. All patients were ambulatory with mostly normal levels of serum bilirubin and albumin concentrations. The reliability of the NIDDK-QA, as measured by test-retest correlation (Pearson coefficients: 0.82-0.99, P <.01) and by internal consistency (Cronbach's alpha: 0.87-0.94) exceeded conventional acceptability criteria. The correlation between domain scores of the NIDDK-QA and SF-36 was clear and logical in that the physical function domain of NIDDK-QA strongly correlated with the physical component summary score of SF-36 (r = 0.86, P <.01). The overall well-being domain of the NIDDK-QA was closely associated with the mental summary score of SF-36 (r = 0.69, P <.01). Among PBC patients, there was a modest yet significant correlation between the Mayo risk score and overall well-being (r = -0.26, P =.03). In the assessment of QOL in patients with cholestatic liver disease, NIDDK-QA is found reliable and valid. These data, combined with our previous study, demonstrate its applicability in a wide spectrum of disease severity, ranging from early, ambulatory-phase disease to decompensated cirrhosis necessitating liver transplantation.

A pilot study of pentoxifylline for the treatment of primary sclerosing cholangitis

OBJECTIVE

There is no effective therapy for patients with primary sclerosing cholangitis (PSC). Rats with experimental small bowel bacterial overgrowth develop hepatobiliary injury similar to PSC. The hepatobiliary injury results from peptidoglycan-polysaccharide-mediated activation of Kupffer cells, release of cytokines such as tumor necrosis factor (TNF-alpha), and is prevented by pentoxifylline. Our aims were to assess the safety and effects of pentoxifylline on symptoms and biochemical liver tests in patients with PSC.

METHODS

A total of 20 patients with clinical, cholangiographic, and histological features of PSC of varying severity were treated with pentoxifylline sustained release (SR) tablets (400 mg q.i.d.) for < or = 1 yr. Serum alkaline phosphatase, aspartate aminotransferase, and bilirubin were monitored every 3 months for 1 year; serum TNF-alpha and TNF receptor subtypes I and II were assessed at baseline and 1 year.

RESULTS

Of 20 patients, 16 tolerated pentoxifylline and completed the study. Two patients were withdrawn because of severe nausea, and two patients were noncompliant with medication and withdrew. Pentoxifylline did not significantly alter symptoms of fatigue or pruritus, serum liver tests, serum TNF-alpha or TNF receptor levels.

CONCLUSIONS

In the current regimen, pentoxifylline alone does not significantly improve symptoms or liver tests in patients with PSC.

Identification and characterization of human mitochondrial tryptophanyl-tRNA synthetase

A full-length cDNA clone encoding the human mitochondrial tryptophanyl-tRNA synthetase (h(mt)TrpRS) has been identified. The deduced amino acid sequence shows high homology to both the mitochondrial tryptophanyl-tRNA synthetase ((mt)TrpRS) from Saccharomyces cerevisiae and to different eubacterial forms of tryptophanyl-tRNA synthetase (TrpRS). Using the baculovirus expression system, we have expressed and purified the protein with a carboxyl-terminal histidine tag. The purified His-tagged h(mt)TrpRS catalyzes Trp-dependent exchange of PP(i) in the PP(i)-ATP exchange assay. Expression of h(mt)TrpRS in both human and insect cells leads to high levels of h(mt)TrpRS localizing to the mitochondria, and in insect cells the first 18 amino acids constitute the mitochondrial localization signal sequence. Until now the human cytoplasmic tryptophanyl-tRNA synthetase (hTrpRS) was thought to function as the h(mt)TrpRS, possibly in the form of a splice variant. However, no mitochondrial localization signal sequence was ever detected and the present identification of a different (mt)TrpRS almost certainly rules out that possibility. The h(mt)TrpRS shows kinetic properties similar to human mitochondrial phenylalanyl-tRNA synthetase (h(mt)PheRS), and h(mt)TrpRS is not induced by interferon-gamma as is hTrpRS.

Stereotactic breast biopsy in a community hospital setting

Our institution began using a stereotactic core needle breast biopsy system for mammographically detected breast lesions in November 1996. The system consists of a LORAD stereo imaging table and an 11-gauge vacuum-assisted mammotome (Biopsys Medical, Irvine, CA). All biopsies were performed with the combined efforts of a radiologist and a surgeon. Three hundred sixteen biopsies were attempted in 279 patients, with multiple biopsies in 31 patients. Indications included microcalcifications in 52 per cent of patients and a mass in 48 per cent of patients. Biopsy was unsuccessful in 20 patients (6.3%). Pathologic diagnoses included invasive ductal carcinoma (19 patients), invasive lobular carcinoma (2), ductal carcinoma in situ (17), atypical ductal hyperplasia (8), atypical lobular hyperplasia (1), fibroadenoma (40), lymph node (7), and benign (202). Invasive cancer, in situ carcinoma, or atypical hyperplasia was diagnosed in 46 (15.6%) lesions. Thirty-six patients had open biopsies. The core biopsy diagnosis was correct in 27 lesions, unable to be confirmed in six cases and changed in four cases, with three lesions upgraded and one case downgraded. The 11-gauge vacuum-assisted mammotome provides excellent accuracy for diagnosing mammographic abnormalities. A combined effort between radiology and surgical services is an effective way of using the stereotactic biopsy system.

Cost-effectiveness of ursodeoxycholic acid therapy in primary biliary cirrhosis

Ursodeoxycholic acid (UDCA) is a safe and effective treatment for patients with primary biliary cirrhosis (PBC), but the cost of this drug has raised concerns regarding cost-effectiveness. The aim of our study was to determine the cost-effectiveness of UDCA in PBC. We compared the costs and outcomes of managing PBC patients with and without UDCA. From two previously published trials, the effectiveness of UDCA was determined by comparing the annual reduction in the development of ascites, varices, variceal bleeding, encephalopathy, liver transplantation, and death between the treatment groups. Average annual costs for each of these events were estimated based on literature and institutional data. Approximately twice as many major events occurred in the placebo group compared with the UDCA group. The relative risk (RR) of liver transplantation (1.95; 95% CI: 1.14-3.68) and development of esophageal varices (3. 11; 95% CI: 1.57-10.65) were significantly higher in the placebo group compared with the UDCA group. There were no significant increases in the RR of ascites, variceal bleeding, encephalopathy, or death between the two groups. Based on the estimated annual cost of managing these events and the annual costs of UDCA ($2,500), there was an annual cost savings per patient of $1,372. Compared with the placebo group, patients receiving UDCA had a lower incidence of major complications and lower medical care costs.

p59OASL, a 2'-5' oligoadenylate synthetase like protein: a novel human gene related to the 2'-5' oligoadenylate synthetase family

The 2'-5' oligoadenylate synthetases form a well conserved family of interferon induced proteins, presumably present throughout the mammalian class. Using the Expressed Sequence Tag databases, we have identified a novel member of this family. This protein, which we named p59 2'-5' oligoadenylate synthetase-like protein (p59OASL), shares a highly conserved N-terminal domain with the known forms of 2'-5' oligoadenylate synthetases, but differs completely in its C-terminal part. The C-terminus of p59OASL is formed of two domains of ubiquitin-like sequences. Here we present the characterisation of a full-length cDNA clone, the genomic sequence and the expression pattern of this gene. We have addressed the evolution of the 2'-5' oligoadenylate synthetase gene family, in the light of both this new member and new 2'-5' oligoadenylate synthetase sequence data from other species, which have recently appeared in the databases.

Detection of antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: a comparison of the alkaline phosphatase and immunofluorescent techniques

BACKGROUND

The reported prevalence of antineutrophil cytoplasmic antibodies (ANCA) in primary sclerosing cholangitis (PSC) varies considerably (26-85%). Part of this may reflect methodological differences but part may reflect the differences in the patient groups analysed. To resolve this issue we compared the sensitivity and specificity of the immunoalkaline phosphatase (IALP) and immunofluorescence (IF) techniques in four different populations.

METHOD

Sera from four centres were tested blind on alcohol-fixed neutrophils using both techniques.

PATIENTS

USA: 14 PSC, 14 primary biliary cirrhosis (PBC); Sweden: 32 PSC, 3 autoimmune hepatitis (AIH), 14 PBC, 11 chronic liver disease; Norway: 32 PSC, 14 AIH, 13 PBC, 1 hepatitis C. Italy: 8 PSC, 14 PBC, 8 viral hepatitis. Thirty-six normal healthy volunteers from Oxford, together with positive and negative controls, were also tested.

RESULTS

The healthy controls were all ANCA negative. The diagnostic sensitivity and specificity, respectively, of ANCA for PSC using the IALP technique for the different test sera were: USA 71% and 93%, Sweden 66% and 96%, Norway 69% and 46%, Italy 50% and 95%. The diagnostic sensitivity and specificity, respectively, of the IF technique on the same sera were: USA 50% and 86%, Sweden 56% and 86%, Norway 47% and 61%, Italy 50% and 91%. Overall, combining all four groups, detection of ANCA using the IALP technique gave a diagnostic sensitivity of 66% with a specificity of 74% for PSC. In contrast, the IF technique gave an overall diagnostic of only 51% (P = 0.044, compared with IALP) with a specificity of 73%. Although overall the IALP technique was more sensitive than IF, the differences in sensitivity and specificity between the two techniques did not reach statistical significance for any individual group. Furthermore, the small differences in sensitivity between the four groups using either technique were not significant. However, the IALP technique had greater specificity in the US, Swedish and Italian groups compared with the Norwegian group (P < 0.05) whereas no statistically significant differences in specificity were noted between the groups using the IF technique.

CONCLUSION

This study shows that the IALP method of ANCA detection is at least as sensitive as IF for the serological diagnosis of PSC. Indeed, combining data from all four centres, the IALP technique was significantly more sensitive than IF. We therefore recommend the use of the IALP technique, which is also easier to interpret and does not require the use of a specialist fluorescent microscope. The lack of a wide variation in sensitivity between IALP and IF for any individual patient group reported in this study suggests that the previously reported regional differences in ANCA prevalence in PSC of between 26% and 85% may be patient, related, rather than due to ethnic or methodological differences in ANCA detection, perhaps reflecting possible disease heterogeneity within PSC, or case selection bias. Further studies are needed to investigate this intriguing possibility. Such differences, if confirmed, will need to be taken into account when assessing the use of ANCA as a serological marker of PSC.

Preferential exclusion of hybrids in mixed pollinations between oilseed rape (Brassica napus) and weedy B. campestris (Brassicaceae)

In most experimental hybridizations between oilseed rape (Brassica napus) and weedy B. campestris, either intra- or interspecific pollen has been applied to individual flowers. Under field conditions, however, stigmas will often receive a mixture of the two types of pollen, thereby allowing for competition between male gametophytes and/or seeds within pods. To test whether competition influences the success of hybridization, pollen from the two species was mixed in different proportions and applied to stigmas of both species. The resulting seeds were scored for paternity by isozyme and randomly amplified polymorphic DNA analysis. Using data on the proportion of fully developed seeds and the proportion of these seeds that were hybrids, a statistical model was constructed to estimate the fitness of conspecific and heterospecific pollen and the survival of conspecific and heterospecific zygotes to seeds. B. campestris pollen in B. napus styles had a significantly lower fitness than the conspecific pollen, whereas no difference between pollen types was found in B. campestris styles. Hybrid zygotes survived to significantly lower proportions than conspecific zygotes in both species, with the lowest survival of hybrid zygotes in B. napus pods. This is in contrast to the higher survival of hybrid seeds in B. napus than in B. campestris pods when pollinations are made with pure pollen. Altogether, the likelihood of a foreign pollen grain producing a seed was much lower on B. napus than on B. campestris. In addition, pods on B. napus developed to a lower extent the more heterospecific pollen was in the mix, whereas this had no effect on B. campestris.

The origin of land plants: a union of alga and fungus advanced by flavonoids?

This paper addresses the hypothesis that land plants have a biphyletic origin as the product of an endocellular mutualism between a green alga and a tip-growing, fungus-like organism, culminating in the acquisition of part of the latter's genome by the host alga (Atsatt, P.R., 1988, Are vascular plants 'inside-out' lichens? Ecology 69, 17-23). According to this hypothesis, the tip-growing symbiont's capacity for invasive growth was exploited during the further evolution of the holobiont for the development of various specialized plant cell types, but especially those displaying tip growth. Here, noting the recent discovery of the dependence of pollen tube tip growth on flavonoids, this hypothesis is refined and extended by suggesting that a symbiotic relationship was advanced by the evolution of UV-protective flavonoids in the alga, followed by the evolution of a growth response by the tip-growing symbiont to the presence of those flavonoids, allowing the symbiont to continue to live with the alga in its new, high-light habitat. This growth response then evolved into a dependence on flavonoids in the context of an obligate, mutualistic relationship progressing toward endosymbiosis and incorporation of the endocytobiont's genetic capacity for cell polarization, tip growth and their control into the host alga's genome. Land plants and advanced charophycean algae (which are the closest green-algal relatives of land plants) are likely products of this process, while a primitive charophycean alga (lacking both tip growth and cell polarization) is proposed to have been the likely host for the endocytobiont. A series of tests of this hypothesis, based mainly on the identification and molecular phylogenetic analysis of appropriate genes, are proposed. Whether the endocytobiont could have been a relative of the earliest endomycorrhizal fungi is assessed.

Hypercholesterolemia and atherosclerosis in primary biliary cirrhosis: what is the risk?

Hypercholesterolemia is commonly associated with primary biliary cirrhosis. In the general population, elevated serum cholesterol is associated with an increased risk of atherosclerosis. The relative risk has been poorly defined in primary biliary cirrhosis patients with hyperlipidemia. In addition, the hyperlipidemic state seen with primary biliary cirrhosis has not been well studied. We prospectively observed 312 patients with primary biliary cirrhosis for a median of 7.4 yr. During this period, 128 patients died. The incidence of atherosclerotic death in patients with primary biliary cirrhosis was not statistically different when compared with an age-matched and sex-matched U.S. control population. A similar group of 50 consecutive PBC patients had detailed serum lipid profiles. Findings included progressive increases in total cholesterol and low-density lipoprotein cholesterol with an increasing histological stage or severity of disease. High-density lipoprotein cholesterol was elevated in all stages, with the highest levels in histological stage 2 and 3 disease. Triglycerides were normal or slightly elevated in all stages. Apoprotein A-I was elevated in all but histological stage 4 disease. Our study suggests the hyperlipidemia associated with primary biliary cirrhosis does not place these patients at risk for atherosclerotic death. In light of the limitations imposed by our relatively small sample size, however, additional patients should be studied. Furthermore, an examination of the pathophysiological mechanisms leading to hypercholesterolemia should be the topic of further study.

Altered gene expression in plants due to trans interactions between homologous genes

We have attempted to explain co-suppression in terms of a hypothesis whereby homologous sequences are able to interact somatically in trans, in a manner influenced by sequence context or location. We have speculated that there might be mechanistic similarities between co-suppression and some other trans interaction and epigenetic phenomena in plants, fungi and animals; and that it might be the sequence context in which a gene lies, or its location in the genome that influences the likelihood that it will participate in these phenomena. We suspect that elucidation of the mechanisms behind these phenomena will play a role in developing a better understanding of the relationship between nuclear architecture and gene expression. This, in turn, will be helpful in understanding the developmental regulatory mechanisms that exert control over somatic trans interactions in plants, and perhaps in understanding some aspects of the basis of cellular differentiation in development.

Introduction of a Chimeric Chalcone Synthase Gene into Petunia Results in Reversible Co-Suppression of Homologous Genes in trans

We attempted to overexpress chalcone synthase (CHS) in pigmented petunia petals by introducing a chimeric petunia CHS gene. Unexpectedly, the introduced gene created a block in anthocyanin biosynthesis. Forty-two percent of plants with the introduced CHS gene produced totally white flowers and/or patterned flowers with white or pale nonclonal sectors on a wild-type pigmented background; none of hundreds of transgenic control plants exhibited such phenotypes. Progeny testing of one plant demonstrated that the novel color phenotype co-segregated with the introduced CHS gene; progeny without this gene were phenotypically wild type. The somatic and germinal stability of the novel color patterns was variable. RNase protection analysis of petal RNAs isolated from white flowers showed that, although the developmental timing of mRNA expression of the endogenous CHS gene was not altered, the level of the mRNA produced by this gene was reduced 50-fold from wild-type levels. Somatic reversion of plants with white flowers to phenotypically parental violet flowers was associated with a coordinate rise in the steady-state levels of the mRNAs produced by both the endogenous and the introduced CHS genes. Thus, in the altered white flowers, the expression of both genes was coordinately suppressed, indicating that expression of the introduced CHS gene was not alone sufficient for suppression of endogenous CHS transcript levels. The mechanism responsible for the reversible co-suppression of homologous genes in trans is unclear, but the erratic and reversible nature of this phenomenon suggests the possible involvement of methylation.

Introduction of a Chimeric Chalcone Synthase Gene into Petunia Results in Reversible Co-Suppression of Homologous Genes in trans

We attempted to overexpress chalcone synthase (CHS) in pigmented petunia petals by introducing a chimeric petunia CHS gene. Unexpectedly, the introduced gene created a block in anthocyanin biosynthesis. Forty-two percent of plants with the introduced CHS gene produced totally white flowers and/or patterned flowers with white or pale nonclonal sectors on a wild-type pigmented background; none of hundreds of transgenic control plants exhibited such phenotypes. Progeny testing of one plant demonstrated that the novel color phenotype co-segregated with the introduced CHS gene; progeny without this gene were phenotypically wild type. The somatic and germinal stability of the novel color patterns was variable. RNase protection analysis of petal RNAs isolated from white flowers showed that, although the developmental timing of mRNA expression of the endogenous CHS gene was not altered, the level of the mRNA produced by this gene was reduced 50-fold from wild-type levels. Somatic reversion of plants with white flowers to phenotypically parental violet flowers was associated with a coordinate rise in the steady-state levels of the mRNAs produced by both the endogenous and the introduced CHS genes. Thus, in the altered white flowers, the expression of both genes was coordinately suppressed, indicating that expression of the introduced CHS gene was not alone sufficient for suppression of endogenous CHS transcript levels. The mechanism responsible for the reversible co-suppression of homologous genes in trans is unclear, but the erratic and reversible nature of this phenomenon suggests the possible involvement of methylation.

Introduction of a Chimeric Chalcone Synthase Gene into Petunia Results in Reversible Co-Suppression of Homologous Genes in trans

We attempted to overexpress chalcone synthase (CHS) in pigmented petunia petals by introducing a chimeric petunia CHS gene. Unexpectedly, the introduced gene created a block in anthocyanin biosynthesis. Forty-two percent of plants with the introduced CHS gene produced totally white flowers and/or patterned flowers with white or pale nonclonal sectors on a wild-type pigmented background; none of hundreds of transgenic control plants exhibited such phenotypes. Progeny testing of one plant demonstrated that the novel color phenotype co-segregated with the introduced CHS gene; progeny without this gene were phenotypically wild type. The somatic and germinal stability of the novel color patterns was variable. RNase protection analysis of petal RNAs isolated from white flowers showed that, although the developmental timing of mRNA expression of the endogenous CHS gene was not altered, the level of the mRNA produced by this gene was reduced 50-fold from wild-type levels. Somatic reversion of plants with white flowers to phenotypically parental violet flowers was associated with a coordinate rise in the steady-state levels of the mRNAs produced by both the endogenous and the introduced CHS genes. Thus, in the altered white flowers, the expression of both genes was coordinately suppressed, indicating that expression of the introduced CHS gene was not alone sufficient for suppression of endogenous CHS transcript levels. The mechanism responsible for the reversible co-suppression of homologous genes in trans is unclear, but the erratic and reversible nature of this phenomenon suggests the possible involvement of methylation.

Monocular ischemia--the influence of carotid atherosclerosis versus primary ocular disease on prognosis

The etiology of monocular ischemia influences the clinical manifestation and long-term neurologic and visual prognosis. During a 10-year period, 140 patients with monocular visual symptoms were evaluated and assigned to a carotid bifurcation occlusive disease group (group I) or a primary ocular disease group (group II) on the basis of angiographic findings and ophthalmologic evaluation. Patients with symptoms secondary to emboli from the carotid bifurcation tended to have a shorter duration of blindness and a lower incidence of permanent blindness initially and during follow-up. The presence of Hollenhorst plaques or retinal artery occlusion did not have any discriminatory diagnostic value since the incidence was similar in both patient groups. Since both primary eye disease and carotid bifurcation occlusive disease can be initially seen as monocular ischemia, carotid angiography and ophthalmologic consultation are necessary to select those patients who will benefit from carotid endarterectomy.

Localization of ectopic parathyroid adenomas by the technetium-thallium subtraction scan

Among numerous methods utilized for preoperative localization of hyperfunctioning ectopic parathyroid tissue, the technetium-thallium scan appears to be a major advance. Eight patients are presented where this method located ectopic parathyroid tissue in the neck, in the mediastinum, within the pericardium, and within the thyroid gland. To date, these findings have been confirmed operatively in five of the eight patients. On the basis of our limited experience, the authors believe that this is a valuable method in the preoperative localization of ectopic parathyroid tissue, especially in patients with persistent or recurrent hyperparathyroidism following a thorough neck exploration.

Insulin resistance in amyotrophic lateral sclerosis

Over the last 30 years glucose intolerance has been reported in a significant percentage of patients with amyotrophic lateral sclerosis (ALS). Currently, a controversy exists in determining whether the carbohydrate abnormality is disease-specific or secondary to decreased glucose utilization due to muscle atrophy. A reduction in glucose receptor space had been postulated for a number of neuromuscular diseases including ALS. In order to clarify this issue we have estimated in vivo insulin sensitivity, using the euglycemic insulin clamp technique, in ALS patients and two control groups, matched according to percent ideal weight. The results showed that the glucose infusion rate, an estimate of in vivo insulin sensitivity, ws significantly diminished in ALS patients compared to both normal and disease controls. These results demonstrate that the insulin resistance in this disorder cannot be explained by a decrease in glucose-receptor space and suggest a primary carbohydrate aberration in the disease process itself.

The presence of platelet-activating factor (PAF) in normal human mixed saliva

This report describes PAF activity in normal human mixed saliva from each of 24 randomly selected donors. The human salivary PAF (HS-PAF) was similar to rabbit basophil PAF (acetyl glyceryl ether phosphorylcholine or AGEPC) with respect to the following characteristics: 1. HS-PAF co-chromatographed with the standard rabbit basophil AGEPC and with synthetic AGEPC. 2. HS-PAF and AGEPC were unaffected by hirudin, indomethacin, and creatine phosphate/creatine phosphokinase, the respective inhibitors of platelet activation induced by thrombin, arachidonic acid, and ADP. 3. HS-PAF and AGEPC were inactivated by a 5-min incubation with ALF, the acid-labile factor in normal human serum that rapidly destroys AGEPC. 4. HS-PAF was demonstrated to be functionally similar to AGEPC by cross-desensitization experiments. In the absence of Ca++, HS-PAF and AGEPC cross-desensitized washed rabbit platelets to subsequent stimulation by either HS-PAF or AGEPC after recalcification. 5. HS-PAF was demonstrated to be structurally similar to AGEPC by several simple chemical tests for functional groups.

The presence of platelet-activating factor (PAF) in normal human mixed saliva

This report describes PAF activity in normal human mixed saliva from each of 24 randomly selected donors. The human salivary PAF (HS-PAF) was similar to rabbit basophil PAF (acetyl glyceryl ether phosphorylcholine or AGEPC) with respect to the following characteristics: 1. HS-PAF co-chromatographed with the standard rabbit basophil AGEPC and with synthetic AGEPC. 2. HS-PAF and AGEPC were unaffected by hirudin, indomethacin, and creatine phosphate/creatine phosphokinase, the respective inhibitors of platelet activation induced by thrombin, arachidonic acid, and ADP. 3. HS-PAF and AGEPC were inactivated by a 5-min incubation with ALF, the acid-labile factor in normal human serum that rapidly destroys AGEPC. 4. HS-PAF was demonstrated to be functionally similar to AGEPC by cross-desensitization experiments. In the absence of Ca++, HS-PAF and AGEPC cross-desensitized washed rabbit platelets to subsequent stimulation by either HS-PAF or AGEPC after recalcification. 5. HS-PAF was demonstrated to be structurally similar to AGEPC by several simple chemical tests for functional groups.

Cyclic AMP-stimulated phosphorylation of bovine tracheal smooth muscle contractile and non-contractile proteins

1. Various proteins isolated from bovine tracheal smooth muscle were examined as phosphate acceptor substrates for a cyclic AMP-dependent protein kinase isolated from the same tissue. A fraction prepared in a manner similar to that of skeletal muscle troponin was the best substrate of the presumptive contractile proteins isolate. Actomyosin and tropomyosin were relatively poor substrates. 2. An assay was developed for the rapid detection in a large number of samples of the muscle specific substrate for the protein kinase on which we reported previously. 3. Using this assay, the muscle specific substrate found in bovine tracheal smooth muscle was partially purified resulting in a preparation which when resolved by polyacrylamide gel electrophoresis showed a single peak of 32P incorporated, and which could be further characterized. 4. Our findings suggest that the substrate contains a protein subunit of molecular weight 19 000, which can be phosphorylated at serine and threonine residues, in the presence of cyclic AMP and protein kinase. The phosphate is in a covalent ester linkage with these residues. 5. A phosphoprotein phosphatase was isolated from the bovine tracheal smooth muscle. 6. Bovine tracheal smooth muscle contains cyclic AMP dependent protein kinase and phosphoprotein phospahatase activity as well as the muscle specific substrate, suggesting that these elements may be part of a mechanism which regulates smooth muscle tone.

CHANGES IN MILK, WHEY, AND BLUE CHEESE AS INDUCED BY BENZOYL PEROXIDE1,2

Milk proteins were subjected to treatment with various levels of benzoyl peroxide, with and without heating at 60 C for 2 h. Heating had a pronounced effect on whey proteins, but polyacrylamide gel electrophoresis revealed changes in proteins not attributable to heat alone. The effect on proteins was reflected in an increased tendency for the benzoyl peroxide-heat treated cheeses to expel moisture during leakage tests. Use of 17.8 ppm benzoyl peroxide resulted in a markedly whiter cheese than that made using 5.9 ppm and reflectance studies indicated this to be true even when no heat treatment accompanied the benzoyl peroxide. Use of benzoyl peroxide in the bleaching process did not decrease mold development in ripening loaves nor was acid production by lactic cultures diminished. In addition, proteolysis of milk proteins by rennet was not reduced by the presence of benzoyl peroxide.