Nucleotide sequence of nine protein-coding genes and 22 tRNAs in the mitochondrial DNA of the sea star Pisaster ochraceus

We have cloned and sequenced over 9 kb of the mitochondrial genome from the sea star Pisaster ochraceus. Within a continuous 8.0-kb fragment are located the genes for NADH dehydrogenase subunits 1, 2, 3, and 4L (ND1, ND2, ND3, and ND4L), cytochrome oxidase subunits I, II, and III (COI, COII, and COIII), and adenosine triphosphatase subunits 6 and 8 (ATPase 6 and ATPase 8). This large fragment also contains a cluster of 13 tRNA genes between ND1 and COI as well as the genes for isoleucine tRNA between ND1 and ND2, arginine tRNA between COI and ND4L, lysine tRNA between COII and ATPase 8, and the serine (UCN) tRNA between COIII and ND3. The genes for the other five tRNAs lie outside this fragment. The gene for phenylalanine tRNA is located between cytochrome b and the 12S ribosomal genes. The genes for tRNA(glu) and tRNA(thr) are 3' to 12S ribosomal gene. The tRNAs for histidine and serine (AGN) are adjacent to each other and lie between ND4 and ND5. These data confirm the novel gene order in mitochondrial DNA (mtDNA) of sea stars and delineate additional distinctions between the sea star and other mtDNA molecules.

Age-related differences in norepinephrine kinetics: effect of posture and sodium-restricted diet

We used compartmental analysis to study the influence of age on the kinetics of norepinephrine (NE) distribution and metabolism. Plasma NE and [3H]NE levels were measured in 10 young (age 19-33 yr) and 13 elderly (age 62-73 yr) subjects in the basal supine position, during upright posture, and after 1 wk of a sodium-restricted diet. We found that the basal supine release rate of NE into the extravascular compartment, which is the site of endogenous NE release (NE2), was significantly increased in the elderly group (young, 9.6 +/- 0.5; elderly, 12.3 +/- 0.8 nmol.min-1.m-2; means +/- SE; P = 0.016), providing direct evidence for an age-related increase in sympathetic nervous system (SNS) tone. Although upright posture led to a greater increase in plasma NE in the young (0.90 +/- 0.07 to 2.36 +/- 0.16 nM) than in the elderly (1.31 +/- 0.11 to 2.56 +/- 0.31 nM; age group-posture interaction, P = 0.02), the increase in NE2 was similar between the young (9.6 +/- 0.6 to 16.2 +/- 1.5 nmol.min-1.m-2) and the elderly (11.6 +/- 1.4 to 16.1 +/- 2.4 nmol.min-1.m-2; posture effect, P = 0.001; age group-posture interaction, P = 0.15). Thus the increase in SNS tone resulting from upright posture was similar in young and elderly subjects. Plasma NE levels increased similarly in both groups after a sodium-restricted diet (diet effect, P = 0.001; age group-diet interaction, P = 0.23). However, NE2 did not increase significantly in either group (diet effect, P = 0.26), suggesting that SNS tone did not increase after a sodium-restricted diet. Compartmental analysis provides a description of age-related differences in NE kinetics, including an age-related increase in the extravascular NE release rate.

Intrarenal atrial natriuretic peptide infusion lowers arterial pressure chronically

Chronic intravenous infusions of atrial natriuretic peptide (ANP) have been shown to lower mean arterial pressure (MAP) in both normal and hypertensive animals. However, the importance of the renal actions of ANP in mediating this hypotension is unknown. This study was designed to determine whether physiological or pathophysiological increases in intrarenal ANP levels influence long-term control of arterial pressure. ANP was infused into the renal artery of seven conscious, uninephrectomized, chronically instrumented dogs at 1, 2, and 4 ng.kg-1.min-1 for 7 days at each dose, followed by a recovery period. Then ANP was infused intravenously following the same protocol. MAP decreased from 88 +/- 3 to 78 +/- 3 mmHg during intrarenal infusion of 1 ng.kg-1.min-1 ANP; increasing the ANP infusion rate did not result in a further reduction in MAP. Systemic arterial plasma ANP concentration did not change from control (15 +/- 5 pg/ml) during 1 or 2 ng.kg-1.min-1 intrarenal ANP infusion but increased slightly during 4 ng.kg-1.min-1 intrarenal ANP infusion, averaging 53 +/- 11 pg/ml. Renal arterial plasma ANP concentrations were calculated to increase to approximately 120 +/- 5, 248 +/- 11, and 484 +/- 22 pg/ml during 1, 2, and 4 ng.kg-1.min-1 intrarenal ANP infusion, respectively. Intravenous ANP infusion did not alter MAP at 1 ng.kg-1.min-1, but MAP was slightly lower than control during 2 and 4 ng.kg-1.min-1 ANP infusion and remained below control during the postinfusion period.(ABSTRACT TRUNCATED AT 250 WORDS)

A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif

A search of a 35-kilobase region of the human Y chromosome necessary for male sex determination has resulted in the identification of a new gene. This gene is conserved and Y-specific among a wide range of mammals, and encodes a testis-specific transcript. It shares homology with the mating-type protein, Mc, from the fission yeast Schizosaccharomyces pombe and a conserved DNA-binding motif present in the nuclear high-mobility-group proteins HMG1 and HMG2. This gene has been termed SRY (for sex-determining region Y) and proposed to be a candidate for the elusive testis-determining gene, TDF.

Single-copy DNA distance between two congeneric sea urchin species exhibiting radically different modes of development

We have investigated the differences between nuclear genomes of two purportedly congeneric species of sea urchin that differ radically in early development. Heliocidaris tuberculata develops by means of a typical pluteus larva, whereas H. erythrogramma develops directly from an egg that is 100-fold the volume of the H. tuberculata egg. Reassociation kinetic analysis shows that the kinetic components of the genomic DNA from the two species are essentially the same. No single repeat component explains the 30% difference between the H. erythrogramma and H. tuberculata genomes. Reciprocal hybridization of tracer-labeled single-copy DNA fractions between these species indicates that approximately 50% of the single-copy DNA is sufficiently similar to form hybrids at standard hybridization criterion. Thermal denaturation profiles of the hybridized single-copy DNA sequence yields median (T50H) values of 13.8 degrees-16.5 degrees C. This result suggests a divergence time of 10-13 Mya, which is comparable to divergence times between congeneric sea urchin species in other genera that do not differ significantly in development. Radical differences in early developmental processes can evolve rapidly between closely related forms.

Outcome at discharge for patients in an ongoing follow-up study of hospital treatment

Methodological and practical difficulties have limited the growth of knowledge about outcome of psychiatric hospital treatment. The authors report on outcome at hospital discharge for 103 long-term and 93 short-term patients treated at the C. F. Menninger Memorial Hospital, part of an ongoing follow-up study of hospital treatment. Discharge outcome is based mainly on ratings of symptoms, global functioning, and therapeutic alliance as well as on patients' reports of satisfaction. At discharge both long- and short-term patients were found to have low levels of symptoms (based on the Brief Psychiatric Rating Scale) and a relatively adequate level of functioning (in the 51-to-60 range on the Global Assessment Scale) and to have been highly satisfied with treatment.

Atrial natriuretic peptide induces sustained natriuresis in conscious dogs

Although acute infusions of atrial natriuretic peptide (ANP) often cause natriuresis, these effects are not sustained, possibly because of reductions in arterial pressure or other compensatory adaptations. The aim of this study was to determine whether physiological increases in intrarenal ANP levels cause sustained natriuresis if changes in arterial pressure and other neurohumoral influences that might obscure the renal responses are controlled. Changes in renal function were quantitated during chronic unilateral renal arterial infusion of ANP at rates of 1, 2, and 4 ng.kg-1.min-1 in conscious dogs (n = 7) with the urinary bladder split to allow continuous measurement of renal excretion in the ANP-infused and contralateral, vehicle-infused kidneys. There was no change in mean arterial pressure at any infusion rate. During 1 ng.kg-1.min-1 infusion of ANP for 5 days, the renal excretory responses were small and variable. However, during 2 and 4 ng.kg-1.min-1 ANP infusion for 7 days, sodium excretion averaged 37.2 +/- 10.0 and 134.8 +/- 19.0% greater, respectively, in the ANP-infused kidneys compared with the vehicle-infused kidneys but there were no changes in glomerular filtration rate or effective renal plasma flow. These results demonstrate that when compensatory changes in arterial pressure and neurohumoral factors are controlled, ANP, at physiological concentrations, causes marked increases in renal excretion. This study supports the concept that ANP's effects to increase renal excretory capability could play a role in long-term control of arterial pressure and body fluid homeostasis.

Beta-adrenergic blockade decreases norepinephrine release in humans

Beta-Adrenergic blockade with propranolol (PRP) has been reported to cause an increase in plasma norepinephrine (NE) levels in humans, which suggests that a reflex increase in sympathetic nervous system (SNS) vasoconstrictor tone compensates for the hypotensive effect of beta-adrenergic blockade. However, plasma NE levels are an indirect measure of SNS activity. We have developed a two-compartment model of NE kinetics to estimate NE release into an extravascular compartment as a more comprehensive measure of systemic SNS activity. To determine whether beta-adrenergic blockade alters extravascular NE release, we studied nine healthy subjects during sequential infusions of saline and PRP. During PRP infusion, there was an increase in plasma NE levels [1.03 +/- 0.13 to 1.27 +/- 0.21 (SE) nM; P = 0.05], but the extravascular NE release rate decreased significantly (15.5 +/- 1.6 to 9.2 +/- 1.2 nmol.min-1.m-2, P = 0.0002). The plasma NE concentration increased despite the fall in extravascular NE release rate primarily because the clearance of NE from plasma declined (1.55 +/- 0.08 to 1.18 +/- 0.07 l.min-1.m-2, P = 0.0001); the NE spillover rate into plasma did not change (1.73 +/- 0.18 to 1.75 +/- 0.23 nmol.min-1.m-2, P = 0.89). We conclude that PRP decreases extravascular NE release in humans. Suppression of SNS activity may be an additional mechanism of action of nonselective beta-adrenergic antagonists in humans.

Use of high-energy shock waves for bone cement removal

The revision rate of total hip arthroplasty has increased dramatically over recent years, leading to different methods of extraction of the femoral cement mantle to reduce operative time and surgical risks. The use of high-energy shock waves produced by the Dornier HM.3 Lithotripter to interrupt the cement-bone interface and to reduce the material properties of the cement is investigated. Tests were conducted to measure the pull-out strength of cemented treated rods versus untreated rods, from the medullary canal of canine femurs. The treated femurs showed an average reduction in pull-out strength of 43%. An investigation involving the material properties of acrylic bone cement was also conducted. The properties tested were the compressive modulus of elasticity, the ultimate compressive strength, the ultimate tensile strength, and fracture toughness. The scanning electron microscope aided in determining whether microfractures in the cement resulted from the shock wave treatment. A theoretical study utilizing the finite element method was used to investigate areas of select shock wave treatment about the femoral prosthesis. Analysis of the results showed that the lithotripter treatment had no significant effect on the compressive properties but reduced the tensile properties and fracture toughness significantly. Scanning electron microscopy uncovered definite areas of induced microfractures not present in the control specimens. This study supports the concept of clinically noninvasive, preoperative shock wave treatment prior to total hip revision.

Chronic hyperinsulinemia and blood pressure regulation

The aims of this study were to determine whether chronic hyperinsulinemia, comparable to that found in obese hypertensives, elevates mean arterial pressure (MAP) or potentiates the hypertensive effects of angiotensin II (ANG II). Studies were conducted in conscious dogs with kidney mass reduced by 70% in order to increase their susceptibility to hypertensive stimuli. Insulin infusion (0.5 or 1.0 mU.kg-1.min-1 iv) for 7 days with plasma glucose held constant raised plasma insulin more than fivefold but did not increase MAP in four dogs on 138 meq/day Na intake. In seven dogs maintained on a high Na intake (319 meq/day), insulin infusion (1.0 mU.kg-1.min-1) for 28 days raised fasting insulin from 9.8 +/- 1.5 to 56-78 microU/ml but did not increase MAP, which averaged 106 +/- 2 mmHg during control and 102 +/- 2 mmHg during 28 days of insulin infusion. Insulin caused transient sodium and potassium retention followed by renal "escape" that was associated with increased glomerular filtration rate (12-27%). Plasma renin activity and plasma aldosterone were not altered by insulin. In five dogs infused with ANG II (2.0 ng.kg-1.min-1) to cause mild hypertension, insulin infusion (1.0 mU.kg-1.min-1) for 6-28 days did not increase MAP further. Thus chronic hyperinsulinemia did not elevate MAP, even when kidney mass was reduced, and did not potentiate the hypertensive effects of ANG II. These findings suggest that additional factors besides hyperinsulinemia per se are responsible for obesity-associated hypertension.

The analysis of glycoproteins in cells and tissues by two-dimensional polyacrylamide gel electrophoresis

Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used to identify and analyse subsets of proteins in cells and tissues. The combination of 2-D PAGE and [125I] concanavalin A overlay revealed an extraordinary complexity and diversity in the glycoprotein profiles of different cell types. However, the glycoproteins are not expressed idiosyncratically. Rather, their expression is closely linked to the state of differentiation of a particular cell type. Such glycoproteins can therefore be used to generate antibodies specific for differentiated cells. 2-D PAGE analyses of cellular glycoproteins also revealed a major common glycoprotein of 100 kDa. This was localised to the lumen of the endoplasmic reticulum and is referred to as endoplasmin. The combination of 2-D PAGE with electroblotting and 45Ca overlay revealed that endoplasmin and several other luminal endoplasmic reticulum proteins (reticuloplasmins) are high capacity, low affinity calcium binding proteins which could function as calcium storage proteins in the endoplasmic reticulum. One of these called calreticulin is also found in the sarcoplasmic reticulum. 2-D PAGE and 45Ca overlay has been used to demonstrate the presence of a calcium-binding protein (CP22/sorcin) in the cytosol of rodent multidrug resistant cells. Analyses of murine serum by 2-D PAGE revealed the presence of a novel stress protein serum amyloid P component. These studies illustrate the value of 2-D PAGE when used in combination with detection methods which select specific subsets of proteins such as glycoproteins.

Length heteroplasmy of sturgeon mitochondrial DNA: an illegitimate elongation model

Extensive length polymorphism and heteroplasmy (multiple forms within an individual) of the D-loop region are observed in mitochondrial DNA of the white sturgeon (Acipenser transmontanus). The nucleotide sequence of this region, for both a short and a long form, shows that the differences are due to variable numbers of a perfect 82-bp direct repeat. We propose a model for the replicative origin of length differences, involving a competitive equilibrium between the heavy strand and the D-loop strand. This model suggests that frequent misalignment in the repeat region prior to elongation, facilitated by a stable secondary structure in the displaced strand, can explain both the polymorphism and heteroplasmy in this species.

Ewing's sarcoma of the foot

Ewing's sarcoma is a rare, malignant neoplasm that is most common in children and adolescents. It is common in both the axial and appendicular skeleton but has been rarely reported in the foot. Historically, treatment has consisted of chemotherapy and radiation therapy. The roll of surgery in the management of these lesions have recently been "rediscovered" and depends on the anatomic location. The purpose of this paper is to discuss five consecutive cases of Ewing's Sarcoma of the forefoot treated with below-the-knee amputation for local tumor control. Four of the five patients also underwent some systemic chemotherapy. After comparing the various forms of therapy for this tumor, the benefits of below-the-knee amputation make it an excellent primary treatment for Ewing's sarcoma of the foot.

Twenty-five years of renal trauma at a teaching hospital

In a study of 535 patients with renal trauma admitted to the Medical College of Virginia Hospitals from 1962 to 1988, the authors found indications of a decrease in the rate of total nephrectomy in patients with blunt trauma, due in part to advances in diagnostic technology. In the cases of gunshot wounds, however, a persistently high rate of nephrectomy prevailed, reflecting, the authors believe, the proliferation of increasingly lethal weaponry.

Multiple zones in the sequence of calreticulin (CRP55, calregulin, HACBP), a major calcium binding ER/SR protein

The complete amino acid sequence of CRP55, the major 55 kd calcium binding protein of the ER lumen, was deduced from the murine cDNA nucleotide sequence. This was completed using a novel application of PCR amplification. The mature 399 residue protein encoded is preceded by a 17 amino acid leader sequence and ends in the ER signal sequence, KDEL. The protein contains no calcium binding motifs of the EF hand type or of the form seen in calelectrin-related proteins. The major region of potential low affinity calcium binding sites is a polyacidic stretch towards the C terminus. The primary structure of the protein is markedly zonal. The N-terminal region, of approximately neutral net charge and hydrophobicity, is followed by a central proline-rich zone with repeat sequences separated from the polyacidic C-terminal stretch by a short hydrophobic sequence. The general shape suggested is a globular domain attached to an extended tail. Immunofluorescence studies show that the protein is present in skeletal muscle and indicate that it is a sarcoplasmic reticulum protein. We propose that the protein be named calreticulin to reflect its calcium binding activity and location in the ER and SR.

Downregulation of beta-adrenergic receptor-mediated function during sodium restriction in humans

Mononuclear leukocyte (MNL) beta 2-adrenergic receptor (beta 2-AR) binding and its linked adenylate cyclase sensitivity to isoproterenol were measured in nine healthy humans prior to and after 7 days of dietary sodium restriction to determine whether chronic physiological increases in plasma norepinephrine (NE) are associated with the downregulation of beta-AR-mediated function. Sodium restriction resulted in an increase in the plasma NE concentration (P less than 0.02) and decreases in MNL beta 2-AR density (P less than 0.001), affinity for antagonist (P less than 0.001), and adenylate cyclase sensitivity to isoproterenol (ANOVA, P less than 0.01). To determine whether this downregulation of MNL beta 2-AR-mediated function is related to the increased plasma NE concentration or to increased extravascular NE release, NE kinetics was assessed using compartmental analysis in each subject prior to and after sodium restriction. Sodium restriction caused a decrease in the plasma NE metabolic clearance rate (P less than 0.005) and in the volume of distribution of NE in the intravascular compartment (P less than 0.005), whereas the extravascular NE release rate was unchanged. Our data suggest that the downregulation of MNL beta 2-AR-mediated function in humans during dietary sodium restriction is a response to the increase in plasma NE.

Sustained increases in plasma epinephrine concentration do not modulate renin release

We examined the relationship between plasma renin activity (PRA) and renal arterial pressure (RAP) during 1) control conditions, 2) acute, and 3) chronic intravenous epinephrine (EPI) infusion (125 ng.kg-1.min-1). In eight conscious uninephrectomized dogs maintained on a normal sodium intake, the renin stimulus-response curve (RSRC) was determined by a stepwise reduction in RAP with an inflatable occluder around the renal artery controlled by a servo unit. The RSRC could be approximated by two lines intersecting at a threshold pressure (approximately 20 mmHg below control RAP). In the high-pressure range, PRA was relatively insensitive to changes in RAP, whereas, below threshold pressure, changes in RAP had large effects on PRA. During acute EPI infusion there was approximately a 40% increase in heart rate (control = 57 +/- 3 beats/min) and hematocrit (control = 30 +/- 1%) in association with a rise in plasma EPI concentration from 73 +/- 16 to 1,413 +/- 100 pg/ml; mean arterial pressure (MAP) was unchanged (94 +/- 3 mmHg). Moreover, EPI acutely increased basal PRA from 0.3 +/- 0.1 to 0.8 +/- 0.3 ng angiotensin I.ml-1.h-1 and shifted the RSRC to the right (increasing threshold pressure 7 mmHg) without altering the slope of the RSRC curve either above or below threshold pressure. In contrast, although plasma EPI concentration and hematocrit remained elevated during chronic EPI infusion, heart rate and basal PRA returned to preinfusion values. In addition, there were no significant long-term changes in MAP or in any of the parameters of the RSRC.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular analyses of gene expression during sea star spermatogenesis

We have investigated actin gene expression during the annual spermatogenic cycle of Pisaster ochraceus by Northern blot analyses of testes RNAs pooled from defined spermatogenic stages. Specific probes for cytoplasmic (Cy) and muscle (M) actin gene products detect 2.3 and 2.1 kb transcripts, respectively. In addition, actin-coding sequence probes detect a third, much larger (3.5 kb) transcript designated FAT. Preliminary sequence analyses of two cDNAs representing portions of the FAT transcript show over 90% homology to Pisaster Cy actin at the amino acid level but only 80% nucleotide identity. The expression patterns of these three transcripts, plus two spermiogenic indicator transcripts (H3 histone and beta-tubulin), were determined over the cycle. The Cy transcript is seen at all stages but is ten- to 100-fold higher early in the cycle when mitotic activity predominates. The M transcript appears at the onset of gonadal growth and is maintained at constant levels through spermatogenesis consistent with the expansion of the muscular sheath surrounding the testes. The FAT, H3 histone, and beta-tubulin transcripts reach their highest levels in ripe testes when spermiogenic activity is maximal. The homology of the FAT transcript to actin, and its pattern of expression, suggest the hypothesis that this transcript may encode acrosomal actin.