Insights from a chum salmon (Oncorhynchus keta) genome assembly regarding whole-genome duplication and nucleotide variation influencing gene function

Chum salmon are ecologically important to Pacific Ocean ecosystems and commercially important to fisheries. To improve the genetic resources available for this species, we sequenced and assembled the genome of a male chum salmon using Oxford Nanopore read technology and the Flye genome assembly software (contig N50: ∼2 Mbp, complete BUSCOs: ∼98.1%). We also resequenced the genomes of 59 chum salmon from hatchery sources to better characterize the genome assembly and the diversity of nucleotide variants impacting phenotype variation. With genomic sequences from a doubled haploid individual, we were able to identify regions of the genome assembly that have been collapsed due to high sequence similarity between homeologous (duplicated) chromosomes. The homeologous chromosomes are relics of an ancient salmonid-specific genome duplication. These regions were enriched with genes whose functions are related to the immune system and responses to toxins. From analyzing nucleotide variant annotations of the resequenced genomes, we were also able to identify genes that have increased levels of variants thought to moderately impact gene function. Genes related to the immune system and the detection of chemical stimuli (olfaction) had increased levels of these variants based on a gene ontology enrichment analysis. The tandem organization of many of the enriched genes raises the question of why they have this organization.

Valuation of milk composition and genotype in cheddar cheese production using an optimization model of cheese and whey production

A mass balance optimization model was developed to determine the value of the kappa-casein genotype and milk composition in Cheddar cheese and whey production. Inputs were milk, nonfat dry milk, cream, condensed skim milk, and starter and salt. The products produced were Cheddar cheese, fat-reduced whey, cream, whey cream, casein fines, demineralized whey, 34% dried whey protein, 80% dried whey protein, lactose powder, and cow feed. The costs and prices used were based on market data from March 2004 and affected the results. Inputs were separated into components consisting of whey protein, ash, casein, fat, water, and lactose and were then distributed to products through specific constraints and retention equations. A unique 2-step optimization procedure was developed to ensure that the final composition of fat-reduced whey was correct. The model was evaluated for milk compositions ranging from 1.62 to 3.59% casein, 0.41 to 1.14% whey protein, 1.89 to 5.97% fat, and 4.06 to 5.64% lactose. The kappa casein genotype was represented by different retentions of milk components in Cheddar cheese and ranged from 0.715 to 0.7411 kg of casein in cheese/kg of casein in milk and from 0.7795 to 0.9210 kg of fat in cheese/kg of fat in milk. Milk composition had a greater effect on Cheddar cheese production and profit than did genotype. Cheese production was significantly different and ranged from 9,846 kg with a high-casein milk composition to 6,834 kg with a high-fat milk composition per 100,000 kg of milk. Profit (per 100,000 kg of milk) was significantly different, ranging from $70,586 for a high-fat milk composition to $16,490 for a low-fat milk composition. However, cheese production was not significantly different, and profit was significant only for the lowest profit ($40,602) with the kappa-casein genotype. Results from this model analysis showed that the optimization model is useful for determining costs and prices for cheese plant inputs and products, and that it can be used to evaluate the economic value of milk components to optimize cheese plant profits.

Impact of separating amino acids between plasma, extracellular and intracellular compartments on estimating protein synthesis in rodents

Three models representing different separations of amino acid sources were used to simulate experimental specific radioactivity data and to predict protein fractional synthesis rate (FSR). Data were from a pulse dose of 14C-U Leu given to a non-growing 20-g mouse and a flooding dose of 3H Phe given to a non-growing 200 g rat. Protein synthesis rates estimated using the combined extracellular and intracellular (Ec + Ic) source pool and extracellular and plasma (Ec + Pls) source pool mouse models were 78 and 120% d(-1) in liver, 14 and 16% d(-1) in brain and 15 and 14% d(-1) in muscle. Predicted protein synthesis rates using the Ec + Ic, Ec + Ic + Tr (combined extracellular, intracellular and aminoacyl tRNA source pool) and Ec + Pls rat models were 57, 3.4 and 57% d(-1) in gastrocnemius, 58, 71 and 62% d(-1) in gut, 8.3, 8.4 and 7.9% d(-1) in heart, 32, 23 and 25% d(-1) in kidney, 160, 90 and 80% d(-1) in liver, 57, 5.5 and 57% d(-1) in soleus and 56, 3.4 and 57% d(-1) in tibialis. The Ec + Ic + Tr model underestimated protein synthesis rates in mouse tissues (5.0, 27 and 2.5% d(-1) for brain, liver and muscle) and rat muscles (3.4, 5.5 and 3.4% d(-1) for gastrocnemius, soleus and tibialis). The Ec + Pls model predicted the mouse pulse dose data best and the Ec + Ic model predicted the rat flooding dose data best. Model predictions of FSR imply that identification and separation of the source specific radioactivity is critical to accurately estimate FSR.

NFL1, a Nicotiana tabacum LEAFY-like gene, controls meristem initiation and floral structure

The Arabidopsis LEAFY (LFY) gene product induces cells of the shoot apical meristem to differentiate into floral primordia by acting as a master regulator of downstream floral homeotic genes. Tobacco, an allotetraploid, possesses two homologous genes, NFL1 and NFL2, which are 97% identical in amino acid sequence and share 73% amino acid sequence identity with LFY. In order to test whether the highly conserved tobacco orthologue, NFL1, shares functional identity with LFY, we created transgenic tobacco and Arabidopsis plants that constitutively express the NFL1 cDNA. Our results indicate that NFL1 plays a critical role in the allocation of meristematic cells that differentiate lateral structures such as leaves and branches, thereby determining the architecture of the wild-type tobacco shoot. NFL1 also regulates floral meristem development and does so through the control of cell proliferation as well as cell identity. Surprisingly, unlike ectopic LFY expression, which can act as a floral trigger, ectopic NFL1 expression does not promote severe precocious flowering in Nicotiana tabacum suggesting that variations in amino acid sequence among members of the LFY-like gene family have led to divergence in the functional roles of these genes.

Isolation and characterization of anaerobic ethylbenzene dehydrogenase, a novel Mo-Fe-S enzyme

The first step in anaerobic ethylbenzene mineralization in denitrifying Azoarcus sp. strain EB1 is the oxidation of ethylbenzene to (S)-(-)-1-phenylethanol. Ethylbenzene dehydrogenase, which catalyzes this reaction, is a unique enzyme in that it mediates the stereoselective hydroxylation of an aromatic hydrocarbon in the absence of molecular oxygen. We purified ethylbenzene dehydrogenase to apparent homogeneity and showed that the enzyme is a heterotrimer (alphabetagamma) with subunit masses of 100 kDa (alpha), 35 kDa (beta), and 25 kDa (gamma). Purified ethylbenzene dehydrogenase contains approximately 0.5 mol of molybdenum, 16 mol of iron, and 15 mol of acid-labile sulfur per mol of holoenzyme, as well as a molydopterin cofactor. In addition to ethylbenzene, purified ethylbenzene dehydrogenase was found to oxidize 4-fluoro-ethylbenzene and the nonaromatic hydrocarbons 3-methyl-2-pentene and ethylidenecyclohexane. Sequencing of the encoding genes revealed that ebdA encodes the alpha subunit, a 974-amino-acid polypeptide containing a molybdopterin-binding domain. The ebdB gene encodes the beta subunit, a 352-amino-acid polypeptide with several 4Fe-4S binding domains. The ebdC gene encodes the gamma subunit, a 214-amino-acid polypeptide that is a potential membrane anchor subunit. Sequence analysis and biochemical data suggest that ethylbenzene dehydrogenase is a novel member of the dimethyl sulfoxide reductase family of molybdopterin-containing enzymes.

A rodent model of protein turnover used to design an experiment for measuring the rates of channeling, recycling and protein synthesis

We described previously a mechanistic model of whole-body protein turnover in rodents. Channeling was defined as the flow of amino acids from the extracellular compartment to aminoacyl tRNA and protein synthesis. Recycling was defined as the flow of amino acids from protein degradation to aminoacyl tRNA (protein synthesis) without mixing with the intracellular pool of amino acids. In this paper, the model is applied to tissues and whole body and is used to develop an experimental protocol for estimating protein fractional synthesis rate, recycling and channeling. Channeling, recycling and protein synthesis must be estimated simultaneously because changes in specific radioactivities over time are highly dependent on the rate of protein synthesis. Injection-specific radioactivities, body weights and experimental variation were used with the model to generate data at different rates of recycling and channeling. The data generated were then used to determine the best time points and experimental method to estimate percentages of recycling, channeling and protein synthesis rate by the iterative Method of Maximum Likelihood. Specific radioactivity at each time point was based on simulated data from three rodents at each of six time points. Predicted protein synthesis rates were within 5%/d of observed rates for all methods. Predicted rates of recycling and channeling were generally within 15% of observed rates except recycling in muscle at high channeling and high recycling. Standard deviations of the predictions of percentages of channeling and recycling were between 0.148 and 44.5% for the pulse dose method, 0.0655 and 197% for the continuous infusion method and 0.351 and 962% for the flooding dose method. The experimental design that yields the best estimates of channeling, recycling and protein synthesis is the pulse dose. Changes in amino acid specific radioactivities in the extracellular, aminoacyl tRNA and protein pools were greatest and should be measured at 2, 6, 10, 40, 70 and 100 min in the pulse method.

In vitro studies on the initial reactions of anaerobic ethylbenzene mineralization

Anaerobic mineralization of ethylbenzene by the denitrifying bacterium Azoarcus sp. strain EB1 was recently shown to be initiated by dehydrogenation of ethylbenzene to 1-phenylethanol. 1-Phenylethanol is converted to benzoate (benzoyl coenzyme A) via acetophenone as transient intermediate. We developed in vitro assays to examine ethylbenzene dehydrogenase and 1-phenylethanol dehydrogenase activities in cell extracts of this strain. With p-benzoquinone as the electron acceptor, cell extracts of Azoarcus sp. strain EB1 catalyzed ethylbenzene oxidation at a specific rate of 10 nmol min(-1) [mg of protein](-1) and an apparent K(m) for ethylbenzene of approximately 60 microM. The membrane-associated ethylbenzene dehydrogenase activity was found to oxidize 4-fluoroethylbenzene and propylbenzene but was unable to transform 4-chloro-ethylbenzene, the ethyltoluenes, and styrene. Enzymatic ethylbenzene oxidation was stereospecific, with (S)-(-)-1-phenylethanol being the only enantiomer detected by chiral high-pressure liquid chromatography analysis. Moreover, cell extracts catalyzed the oxidation of (S)-(-)-1-phenylethanol but not of (R)-(+)-1-phenylethanol to acetophenone. When cell extracts were dialyzed, (S)-(-)-1-phenylethanol oxidation occurred only in the presence of NAD(+), suggesting that NAD(+) is the physiological electron acceptor of 1-phenylethanol dehydrogenase. Both ethylbenzene dehydrogenase and 1-phenylethanol dehydrogenase activities were present in Azoarcus sp. strain EB1 cells that were grown anaerobically on ethylbenzene, 1-phenylethanol, and acetophenone, but these activities were absent in benzoate-grown cells.

Hospice legal services: spiritual and counseling dimensions

Explicates the various components of hospice legal services and draws attention to their possible spiritual dimensions. Notes particularly pastoral care implications of the many legal matters associated with the hospice patient.

Recycling, channeling and heterogeneous protein turnover estimation using a model of whole-body protein turnover based on leucine kinetics in rodents

In the companion paper, a whole-body, mechanistic model of protein turnover in a rodent was described and evaluated with independent data sets that used the flooding dose method. On the basis of fitted fluxes, the model was able to predict specific radioactivity changes in the protein and free leucine pools and whole-body protein fractional synthesis rate (FSR). In this paper, results of model simulations of specific radioactivity changes in the flooding dose, pulse dose and continuous infusion methods were compared and the influence of recycling, channeling and multiple protein pools on model behavior were analyzed. For all methods, the percentage of channeling must be estimated to determine whether the extracellular or intracellular pool specific radioactivities better approximate the aminoacyl tRNA pool specific radioactivity. Recycling also affects the specific radioactivity of the aminoacyl-tRNA pool and therefore must be estimated. An analysis of fits of the flooding dose data indicated that 100% channeling was occurring, but the percentage of recycling could not be determined. Multiple protein pools turning over at different rates overestimated FSR by 2-3% at early time points (5 min) and underestimated FSR by 3-6% at 60 min in the flooding dose method. For the pulse dose method, FSR was underestimated by 40-50% at 5 min and underestimated by 9-10% at 60 min. An increase in time to measure FSR caused a decrease in the estimate of FSR (18% over 3 h) for the flooding dose method and an increase in the estimate of FSR (144% over 3 h) for the pulse dose method.

A model of whole-body protein turnover based on leucine kinetics in rodents

The measurement of fractional synthesis rate is based on the following assumptions: amino acids for protein synthesis are supplied by an intracellular pool; amino acids from protein degradation are not recycled preferentially to protein synthesis; and proteins turn over at a homogeneous rate. To test these assumptions, a mechanistic, theoretical model of protein turnover for a nongrowing 26-g mouse was developed on the basis of data from the literature. The model consisted of three protein pools turning over at fast (102 micromol Leu, t1/2= 11.5 h), medium (212 micromol Leu, t1/2 = 16.6 h) or slow (536 micromol Leu, t1/2 = 71.5 h) rates and extracellular (1.69 micromol Leu), leucyl-tRNA (0.0226 micromol Leu) and intracellular (5.72 micromol Leu) amino acid pools that exchanged amino acids. The flow of amino acids from the protein pools to the leucyl-tRNA pool determined the amount of recycling. The flow of amino acids from the extracellular pool to aminoacyl tRNA determined the amount of channeling. Two flooding dose data sets were used to evaluate specific radioactivity changes predicted by the model. Predictions of specific radioactivities using flooding dose, pulse dose or continuous infusion methods indicated that the model can be a useful tool in estimating the rates of channeling and recycling. However, it was found that use of data from flooding dose experiments might cause inaccurate predictions of certain fluxes.

Annojahnin from Annona jahnii: a possible precursor of mono-tetrahydrofuran acetogenins

A new cytotoxic Annonaceous acetogenin, annojahnin (1), was isolated from the twigs of Annona jahnii (Annonaceae) by bioactivity-directed fractionation using lethality to brine shrimp. Compound 1 represents an unusual type of C-37 Annonaceous acetogenin, lacking either tetrahydrofuran (THF) or epoxide rings, bearing a keto group at C-10, and possessing a double bond located two methylenes away from a vicinal diol. The structure and absolute configuration of 1 were elucidated by 1H and 13C NMR, COSY, and single-relayed COSY and from chemical derivatives. 4-Deoxy-18/21-trans-annomontacin 10-one (4) and 4-deoxy-18/21-cis-annomontacin-10-one (5), two semisynthetic mono-THF acetogenins, were prepared from 1 by reactions that mimic the biogenetic pathways. These acetogenins showed selective cytotoxicities, comparable or superior to adriamycin, among six human solid tumor cell lines. Reduction of the 10-keto of 1, to the racemic 10-OH derivative (3), retained the bioactivities as did the conversion of 1 to 4 and 5.

New bioactive triterpenoids from Melia volkensii

Bioactivity-directed fractionation of the root bark of Melia volkensii resulted in the isolation of two new natural products, meliavolkinin (1) and melianin C (3), together with two known compounds, 1,3-diacetylvilasinin (2) and melianin B (4). Jones oxidation of 4 gave compounds 3, 23,24-diketomelianin B (5), and 16,23,24-triketomelianin B (6). The structures of the new compounds were elucidated by spectral and chemical data. Compounds 1-6 all showed marginal cytotoxicities against certain human tumor cell lines, while 5 showed selective cytotoxicities for the human prostate (PC-3) and pancreatic (PACA-2) cell lines with potencies comparable to those of adriamycin.

Initial reactions in anaerobic ethylbenzene oxidation by a denitrifying bacterium, strain EB1

Initial reactions in anaerobic oxidation of ethylbenzene were investigated in a denitrifying bacterium, strain EB1. Cells of strain EB1 mineralized ethylbenzene to CO2 under denitrifying conditions, as demonstrated by conversion of 69% of [14C]ethylbenzene to 14CO2. In anaerobic suspensions of strain EB1 cells metabolizing ethylbenzene, the transient formation and consumption of 1-phenylethanol, acetophenone, and an as yet unidentified compound were observed. On the basis of growth experiments and spectroscopic data, the unknown compound is proposed to be benzoyl acetate. Cell suspension experiments using H2(18)O demonstrated that the hydroxyl group of the first product of anoxic ethylbenzene oxidation, 1-phenylethanol, is derived from water. A tentative pathway for anaerobic ethylbenzene mineralization by strain EB1 is proposed.

SARs of annonaceous acetogenins in rat liver mitochondria

The Annonaceous acetogenins represent a class of compounds with diverse bioactivities, including promising cytotoxicites. These are due, at least in part, to inhibition of complex I in the oxidative phosphorylation pathway in mitochondria. Fourteen Annonaceous acetogenins were tested in a rat liver mitochondrial oxygen uptake assay to probe additional structure-activity relationships. In this subcellular assay, the activity of non-adjacent bis-THF ring acetogenins depends on the distance between the two THF rings; the activity decreases to that of a mono-THF ring acetogenin if the distance is too long. When one THF ring is replaced with a tetrahydropyran ring, the activity remains comparable. The configuration of the THF ring, in mono ring compounds, seems to be more important than stereochemical differences in the rings of adjacent bis-THF ring compounds. Bullatacin, an adjacent bis-THF ring acetogenin, was used as a standard compound in every run to normalize the data.

Diagnostic information as a commodity

In estimating the cost-effectiveness of diagnostic procedures, it is helpful to treat diagnostic information as a commodity with a unit price. The amount of useful information provided by a test result can be measured in binary units (bits), and the unit price of the information produced by the test result can be expressed in dollars per bit in much the same way that the price of gold is given in dollars per ounce. This allows comparison of the unit prices of various diagnostic tests, examination of the effect of multiple testing, and calculation of the most cost-effective conditions for screening tests.

Diagnostic information as a commodity

In estimating the cost-effectiveness of diagnostic procedures, it is helpful to treat diagnostic information as a commodity with a unit price. The amount of useful information provided by a test result can be measured in binary units (bits), and the unit price of the information produced by the test result can be expressed in dollars per bit in much the same way that the price of gold is given in dollars per ounce. This allows comparison of the unit prices of various diagnostic tests, examination of the effect of multiple testing, and calculation of the most cost-effective conditions for screening tests.

Response to patients' death and bereavement in dental practice

Coping with patient deaths and family bereavement has received minimal attention in dental education and literature. This study was conducted to determine how frequently dentists experience patient deaths, how they cope with the knowledge of a patient's death, and if they demonstrate need for emphasis in the dental curricula in the areas of death and bereavement. A survey adapted from Chiodo and Tolle (1988) was sent to all 2091 dentists in the State of Kentucky. The response rate was 47.68% (997 returned surveys). Findings include: (1) General dentists (GDs) have a significantly higher number of patients who die each year than do specialists (S) (GD = 7, S = 1.5); (2) coping behaviors range from sending sympathy cards (63%) to attending the funeral (23%); (3) patient deaths cause stress, most stress occurring when patients die unexpectedly; (4) the greatest stress was encountered when talking with the patient's family; and (5) most dentists (58%) believed that bereavement education should occur in dental school. In conclusion, this research adds to the limited literature on appropriate coping behaviors by dentists when patients die and suggests that death and bereavement education should occur in the dental school setting to prepare practicing dentists for coping with patient loss due to death, and to provide family bereavement support mechanisms.

On the clinical significance of the S-phase fractions of tumors

The S-phase fraction of a tumor cell population is often viewed as a general indicator of the clinical aggressiveness of that tumor. Actually, the S-phase fraction of a cancer should be interpreted as no more than an indicator of the mean duration of its mitotic cycle. The S-phase fraction of a solid tumor is difficult to measure accurately, but in principle it is a powerful predictor of the duration of the recurrence-free interval. However, since the duration of the mitotic cycle does not correlate with malignancy, the S-phase fraction cannot be used to diagnose malignancy. It is of little value in making therapeutic decisions because the duration of the mitotic cycle is not a predictor of invasion and metastasis.

Vasoconstrictor action of angiotensin I-convertase and the synthetic substrate (Pro11,D-Ala12)-angiotensin I

A chymase (also referred to as angiotensin I-convertase) specific for the conversion of angiotensin (Ang) I to Ang II has been identified in human heart. This serine protease is also present in dog and marmoset vasculature. We examined the vasoconstrictor effects of Ang II putatively generated from an angiotensin-converting enzyme (ACE)-resistant convertase synthetic substrate (SUB) in vivo and in vitro. In marmosets, SUB (7 to 700 micrograms/kg i.v.) or Ang I (0.1 to 30 micrograms/kg) caused similar dose-dependent increases in mean arterial pressure (10 to 100 mm Hg) and decreases in heart rate. Pressor effects of SUB were slightly attenuated at low (but not high) doses by captopril (CAP, 1 mg/kg i.v.) and blocked by losartan (5 mg/kg i.v.); in contrast Ang I pressor effects were substantially blocked by both. In isolated canine superior mesenteric artery, Ang I-induced contraction was eliminated by losartan and reduced but not eliminated by 10 mumol/L CAP. When combined with the serine protease inhibitor chymostatin, CAP eliminated Ang I-induced contraction, but chymostatin alone had no effect. SUB-induced contraction was not blocked by CAP but was equally blocked by chymostatin (25 mumol/L) alone or by the combination of CAP (10 mumol/L) and chymostatin (25 mumol/L); losartan (10 mumol/L) eliminated SUB-induced responses. Previous studies have suggested that Ang I-convertase is important for production of Ang II in the heart. Our results are consistent with a potential role for Ang I-convertase in the production of Ang II in the vasculature, resulting in Ang II-mediated vasoconstriction.

Predictive value and informational value of diagnostic test results

If clinical quality assurance and cost-effectiveness of diagnostic testing are to be measured, some sort of measurement of the clinical value of a test result is needed. The predictive value of a test result is not a real measure of its clinical value, and, particularly, when used in the later stages of a diagnostic workup, it can be misleading. Using the same data that go into a calculation of predictive value, the clinical value can be determined according to the amount of useful information that is provided by a test result. Cost-effectiveness can be expressed as dollars per bit of diagnostic information.

Diminishing returns on the road to diagnostic certainty

In the quest for diagnostic certainty, one can be led into a false sense of accomplishment by the results of sensitive, specific, and well-executed diagnostic tests that provide little or no diagnostic information. This is a consequence of the fact that as one approaches diagnostic certainty the useful information returned by diagnostic tests and observations approaches zero. This can be demonstrated by calculating the quantity of useful information provided by a test in a given clinical environment as one approaches certainty of diagnosis.

Diagnosis by the bit: a method for evaluating the diagnostic process

The extent to which a diagnostic observation or test contributes to a diagnosis is usually represented by a conditional, or Bayesian, probability. According to information theory, the contribution of a diagnostic observation can also be measured in bits of information. This offers a representation of the Bayes rule which may be useful in comparing and evaluating diagnostic sequences, since the diagnostic contributions of the various tests, expressed as bits of information, are additive, providing a simple and graphic representation of the diagnostic process.

Massive splenomegaly

A 16 year review of 391 splenectomies performed at New England Medical Center was done to evaluate the morbidity and mortality of patients with drained splenic weights greater than 1,000 grams. Thirty-six met the criteria for study. Twenty men and 16 women with an average age of 55.4 years were identified. Myeloproliferative disorders were the most predominant cause of massive splenomegaly. Pancytopenia and hemolytic complications of the disease processes were the most acute indications for operations. The average time between diagnosis and operative intervention was 42 months. An average of 10 units of blood products were required to correct preoperative coagulopathy. Eleven of 36 patients had postoperative complications. Eight of 21 with drains and an equal number of patients with preliminary splenic arterial ligation had complications. Eight-one per cent of all complications were infection related. Complication increased the length of stay 11 days. The 30 day mortality rate was 11.1 per cent. Sepsis was the major cause of mortality. Closed drainage system provided no demonstrable benefit nor appeared to be the cause of sepsis. No episodes of pulmonary embolic phenomenon or peripheral venous thrombosis were demonstrated. Elective splenectomy in patients with smaller spleens was performed without operative mortality and with 3 per cent morbidity rate. For patients with massive splenomegaly, the average survival time was 28.5 months. The majority of these patients died from complications of the disease. Preoperative coagulopathy, failure to demonstrate a hematologic response to splenectomy and reoperation were clear predictors for decreased long term survival periods.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of thiamine deficiency and ethanol on rat brain catecholamines

In rats treated with a thiamine deficient diet for 30 days the brain content of total thiamine decreased by 27-50%. Thiamine deficiency decreased the dopamine (DA) concentration of the striatum indicating a reduced synthesis of DA. In the hypothalamus the levels of the catecholamine metabolites homovanillic acid (HVA) and 4-hydroxy-3-methoxyphenyl glycol (HMPG) were reduced indicating a reduced DA and noradrenaline (NA) turnover. Animals on a diet containing 5% ethanol had increased concentrations of HVA and HMPG in rest brain indicating an increased DA and NA turnover. The concentration of 1-carboxysalsolinol (1-CSAL) and salsolinol (SAL) in the brain stem was increased in animals receiving ethanol. Thus, both thiamine deficiency and ethanol treatment influenced the catecholamine system in a complex region-dependent way. In the brain regions most susceptible to brain damage in thiamine deficiency, i.e., hypothalamus and brain stem, 1-CSAL and SAL increased most following thiamine deficiency combined with ethanol intake.

Thermal noise and biological information

Thermal noise limits the efficiency of all information-handling systems. This principle, which is a routine consideration in electronics, is just as fundamental to the handling of highly specific information by living organisms. The rapid basal turnover rates of cells and intracellular proteins and the high energy consumption of regulatory organs, previously unaccounted for, can be explained to a large extent by the need to compensate for the steady loss of essential information due to thermal noise.

Burkitt's lymphoma with ileocecal and subdiaphragmatic masses

Approximately 25 new cases of American Burkitt's lymphoma (ABL) are diagnosed and reported yearly. Black patients presenting with ABL occur in less than 5 percent of the reported cases. A 47-year-old black man with ABL and ileocecal masses typical of the disease is presented. Symptoms, physical findings, and radiologic features of the disease are assessed. The combined modality of aggressive surgical extirpation and chemotherapy may improve remission and survival time by reduction of tumor burden.

The influence of acute ethanol on the catecholamine system in man as reflected in cerebrospinal fluid and urine. A new condensation product, 1-carboxysalsolinol

Urine and cerebrospinal fluid (CSF) were collected from 10 healthy male volunteers after ingestion of 120 g ethanol and under similar conditions without ethanol. Dopamine (DA), homovanillic acid (HVA), norepinephrine (NE), 4-hydroxy-3-methoxyphenylglycol (HMPG), 4-hydroxy-3-methoxymandelic acid (HMMA = VMA), 1-carboxysalsolinol (1-CSAL), salsolinol (SAL) and methylated salsolinol (M-SAL) were analyzed with gas chromatography-mass spectrometry. In CSF collected 6 h after ethanol intake the concentration of NE and its metabolite HMPG were significantly elevated (P less than 0.025 and P less than 0.005, respectively) compared to control conditions. The other compounds analyzed did not change significantly. In urine collected during 10 h after ethanol administration the excretion of HMMA was significantly reduced (P less than 0.01) and the HMPG/HMMA ratio was significantly elevated (P less than 0.005) reflecting a change in the peripheral red-ox state during ethanol oxidation. The excretion of DA and its major metabolite HVA did not change. However, the DA-derived condensation products 1-CSAL (from DA and pyruvate) increased (P less than 0.001), while SAL (from DA and acetaldehyde) decreased (P less than 0.005) after ethanol ingestion compared to the control situation. The increased excretion of 1-CSAL indicated that the ethanol metabolism interferes with the glucose metabolism, probably through an acetaldehyde-mediated inhibition of the pyruvate dehydrogenase complex.

Bronchogenic cyst causing superior vena cava obstruction: CT appearance

The CT appearance of bronchogenic cysts is well known. In addition, CT is useful in evaluating cases of suspected superior vena cava (SVC) syndrome. Although most cases of SVC syndrome are caused by malignant diseases, certain benign disorders such as granulomatous infections may be the underlying cause. A case of a bronchogenic cyst causing SVC occlusion is presented here.

Changes in cell density within the human hippocampal formation as a function of age

In this study the entire hippocampal formation, both grey and white matter, was analyzed as a unit and the number of neurons and glia per unit weight was determined. Tissues were obtained from the right cerebral hemispheres of 25 human brains. We found that the neuron population density increases slightly between 20 and 87 years of age. Previous studies using classical stereological techniques or electron-optical image analysis of histological sections have shown no increase of neuron density of the grey matter of the hippocampus with increasing age. However, our data, based upon a technique of cell dispersion and hemacytometer counting, are not strictly comparable. We attribute our findings of an apparent increase in neuron density with age to the fact that we analyzed the entire hippocampal formation, both with white and grey matter, which had undergone senescent shrinkage--particularly within the white matter. The findings of the present study are to be contrasted with an earlier study of the aging visual cortex using 20 of the same brains and employing the same techniques. Taken together, the two reports suggest that age-dependent neuron loss takes place at very different rates in different areas of the human brain and that the mean life span of neurons in the hippocampus is considerably longer than that of the neurons in the visual cortex.

Thermal instability in the endoplasmic reticulum of the rat hepatocyte

The rates of heat denaturation of a protein component of endoplasmic reticulum, NADPH cytochrome c reductase, measured in the temperature range of 37-47 degrees C, show that this protein is highly unstable in the range of temperatures used in clinical hyperthermia. The rate of enzyme inactivation increases some 20-fold as the temperature increases from 37 degrees C to 45 degrees C. The enzyme has an in vitro half-life of only 7 h due to thermal inactivation at 37 degrees C. This suggests a general scheme for the physiological degradation pathway of intracellular proteins in which the first step is rapid thermal denaturation of the molecule followed by a second and slower step of proteolytic degradation. The rapid physiological turnover of intracellular proteins may be an unavoidable cost of maintaining metabolic precision in the presence of thermal noise at normal body temperature.