Short-term Intervals Research Articles

Extracorporeal renal artery reconstruction for renovascular hypertension

Extracorporeal reconstruction can be applied to the successful repair of stenoses in the distal renal artery and its hilar branches. This study evaluates the short- and long-term results of extracorporeal renal artery reconstruction in 65 patients, including 5 children, with renovascular hypertension who were treated from 1974 through 1989. The mean age of the patients was 37 years (range, 7 to 67 years). The cause of the stenoses was arteriosclerosis in 8 patients, fibrodysplasia in 54 patients, and miscellaneous in 3. Hypertension was severe before treatment with a mean blood pressure of 187/147 mm Hg that was reduced to a mean of 159/102 mm Hg after medical therapy. Ten patients had renal dysfunction. Results were evaluated both at short-term intervals (mean, 7.9 months; 64 patients) and long-term intervals (mean, 5.9 years; 60 patients), after surgery. Blood pressure responses were classified as beneficial (cured/improved) or failures. Anatomic results were evaluated by angiography in 98% of the patients at the short-term interval and in 77% of the patients at the long-term interval. Extracorporeal renal artery surgery was performed on 78 kidneys among 65 patients (unilateral, 45 patients; bilateral, 13 patients; unilateral extracorporeal and contralateral in situ, 7 patients). In most of the cases autologous arterial graft was used for reconstruction. Early in the series one patient died as a result of the operative procedure (1/65, 1.5%). A beneficial blood pressure response occurred in 53 patients (53/65; 82%) at the short-term interval and in 49 patients (49/61; 80%) at the long-term interval, with the average blood pressure at the short-term interval being 138/85 mm Hg and at the long-term interval being 139/85 mm Hg. Renal function improved in all patients with preoperative renal dysfunction. Graft stenosis or occlusion of the main renal artery was neither observed at the short-term interval nor at the long-term interval. However, residual stenoses were observed in 9 of the 163 reconstructed distal branches (5.5%). Extracorporeal renal artery reconstruction with autologous arterial grafts can be effectively applied to lesions of the distal main renal artery and its hilar branches with durable functional results.

Incidence and ecology of marine fouling organisms in the Eastern Harbour of Alexandria, Egypt

The seasonal changes, intensity and constituents of fouling developed on exposed test panels for short and long term intervals are studied in relation to the prevailing environmental conditions in the Eastern Harbour of Alexandria, during March 1983 to March 1984. The intensity of fouling on exposed test panels for long durations is considerably more dense than the total fouling developed on exposed panels for short term successively during the same period. The fouling colonized on submerged panels for long intervals reach to a “saturation point” after 3 to 6 successive months.

Natural variability of pulmonary haemodynamics.

In the interpretation of the effect of a drug or intervention in a single patient, it is desirable to know the spontaneous fluctuations of the variable under study. A few studies have determined pulmonary haemodynamic variability in acute and short-term intervals. It seems reasonable to adopt a confidence limit of 6 mmHg or 22% for PPA changes to be significant. The long-term evolution is difficult to determine because of the unavoidable patient selection for repeat examinations several years apart, and because of the necessary treatment. In slight or moderate pulmonary hypertension the changes in PPA with time seem to be of small magnitude: less than 1 mmHg per year.

Distribution of short-term rms levels in conversational speech.

For 30 male and 30 female talkers, distributions of short-term rms speech levels, relative to the corresponding long-term rms levels, were determined in each of eight 1/3-oct bands for six short-term measurement intervals. Consecutive, Hanning-windowed, 20-ms time records were combined to produce nominal measurement intervals ranging from 20 to 120 ms. For each measurement interval, mean distributions of short-term rms speech levels relative to long-term levels were very similar for male and female talkers, and intertalker differences were small, especially for short-term amplitudes above the median level. The distribution of short-term rms speech levels relative to long-term rms speech levels varied with measurement interval for the short-term measurements. The effects of measurement interval was least for the highest amplitude speech levels and increased as speech levels decreased. For short-term amplitudes above the median level, the effect of measurement interval was greater in higher frequency regions, whereas for short-term amplitudes below the median level, measurement interval had the greatest effect on the lower frequency bands. These data may facilitate comparisons among investigations using different measurement intervals. In addition, they have implications for amplification strategies.

FIELD ESTIMATES OF AMMONIA VOLATILIZATION FROM SWINE MANURE BY A SIMPLE MICROMETEOROLOGICAL TECHNIQUE

An existing numerical model for particle diffusion into air from ground-based sources has been recalculated for circular source plots of 7 m diameter. Results show that a satisfactory relationship between horizontal flux of the diffusing gas at a single measuring height above the center of the plot and flux density from the plot can be defined. This provides a simple technique for comparing volatilization rates of ammonia from treated and untreated manure in the field, under outdoor conditions. The technique has been applied to the study of effects of monocalcium phosphate (MCP) addition on ammonia volatilization from swine manure (Sus scrofa domesticus). Mean ammonia flux densities during peak volatilization periods of the first 3 d after spreading were lower for MCP-treated plots by an average of 17%, with a maximum reduction of 30%. Variability of results from short-term sampling intervals (1–2 h) was high. This made short-term detection of differences of <20% difficult under the adopted experimental procedures. Observations for volatilization from source plots of equal source strength, as well as from source plots with different degrees of dilution of applied manure, permitted a further definition of the sensitivity of the technique. Suggestions are given for possible reductions in variability from improved experimental procedure. Key words: Ammonia volatilization, manure, monocalcium phosphate simulation of diffusion

Diagnostic Continuity From Preschool to Middle Childhood

Most previous studies of preschool outcome have examined a limited range of psychiatric disorders and have used short-term follow-up intervals. The present investigation reports on the 5-year diagnostic and symptom outcome of 98 children who attended a therapeutic preschool program. Time I diagnoses, based on DSM-III criteria, fell into five broad categories: no Axis I diagnosis, conduct-type disorders, attention deficit disorder (ADD), emotional disorders, and developmental delay. Results indicated that children with developmental delay or ADD were most likely to receive the same diagnosis at follow-up, whereas conduct-type and neurotic children showed less diagnostic stability. Most previous studies of preschool outcome have examined a limited range of psychiatric disorders and have used short-term follow-up intervals. The present investigation reports on the 5-year diagnostic and symptom outcome of 98 children who attended a therapeutic preschool program. Time I diagnoses, based on DSM-III criteria, fell into five broad categories: no Axis I diagnosis, conduct-type disorders, attention deficit disorder (ADD), emotional disorders, and developmental delay. Results indicated that children with developmental delay or ADD were most likely to receive the same diagnosis at follow-up, whereas conduct-type and neurotic children showed less diagnostic stability.

The Federal Reserve's new operating procedures: A post mortem

Although money stock targeting has been the strategic focus of Federal Reserve policy since the mid-1970's, operating policy — the tactics whereby the longer-run strategy is implemented over short-term intervals — has been changed by the Federal Reserve at least twice over this period. A particularly dramatic change in operating policy was announced by the Federal Reserve in October 1979. This paper provides empirical evidence that settles questions about the nature of this change and suggests that the new operating procedures may have contributed to the heightened interest rate volatility experienced over the 1979 to 1982 period.

Note on loss of regularity for solutions of the 3?D incompressible euler and related equations

One of the central problems in the mathematical theory of turbulence is that of breakdown of smooth (indefinitely differentiable) solutions to the equations of motion. In 1934 J. Leray advanced the idea that turbulence may be related to the spontaneous appearance of singularities in solutions of the 3—D incompressible Navier-Stokes equations. The problem is still open. We show in this report that breakdown of smooth solutions to the 3—D incompressible slightly viscous (i.e. corresponding to high Reynolds numbers, or “highly turbulent”) Navier-Stokes equations cannot occur without breakdown in the corresponding solution of the incompressible Euler (ideal fluid) equation. We prove then that solutions of distorted Euler equations, which are equations closely related to the Euler equations for short term intervals, do breakdown.

Effects of short-term exposure to catecholestrogens on serum concentrations of gonadotrophins and metabolism of catecholestrogens in ovariectomized rats.

Equimolar amounts (36.8 nmol) of estradiol and the two catecholestrogens (CE's) 4-hydroxyestradiol (4-OHE2) and 2-hydroxyestradiol (2-OHE2) were injected subcutaneously to ovariectomized adult rats. Serum levels of both LH and FSH were determined at short-term intervals. Moreover, serum levels of the administered steroids and their main free and conjugated metabolites were monitored. Serum levels of the injected steroids reached peak values at different time points: estradiol between 60 and 240 min, CE's between 30 and 60 min. Peak height also differed significantly: with estradiol highest (1500 pg/ml), followed by 4-OHE2 (540 pg/ml) and then 2-OHE2 (135 pg/ml) (ratio 11:4:1). This mirrored the different MCR's of the steroids: CE's, especially 2-OHE2, were rapidly and extensively methylated and/or - to a lesser degree - conjugated. Estradiol remained mainly unchanged. LH-serum levels in steroid treated animals showed - irrespective of the steroid used - a uniform reaction pattern: they were significantly depressed 60 to 240 min after injection and - with the exception of estradiol treated rats - reached pretreatment levels again 480 min after injection. Ultra-short (15 min) effects were not observed. FSH serum levels in CE treated animals were not significantly altered, only E2 application led to a significant but small decrease in FSH levels 240 and 480 min after its injection. In conclusion, neither the effect of 4-OHE2 nor that of 2-OHE2 corresponded to the different MCR's or the MCR-corrected affinities for the classical estrogen receptor. A non-genomic mechanism may be responsible for this impaired effect of CE's.

Sublethal fractionated total-body irradiation and donor bone marrow infusion for induction of allograft tolerance.

Tolerance to skin allografts across the strong histocompatibility barrier H-2b to H-2d was achieved with sublethal fractionated total-body irradiation, FTBI, delivered to H-2d mice in 3 doses of 250 rads within 24 hr, followed by transfusion of 3 X 10(7) H-2b donor bone marrow (BM) cells. H-2b skin allografts were applied within 48 hr after the initial radiation. 70% of the mice became long-term (greater than 180-day) survivors with fur-bearing grafts. Marked interexperiment variability in survival rates suggested that infection was the major cause of death in this model and lower weight gain and survival rates for allogenic BM vs. media-treated controls suggested that graft-versus-host disease (GVHD) was also a factor. The observation, however, that long-term survivors (70% of all mice) gained weight and appeared healthy suggested that the GVHD might be self-limiting. Chimeric analysis revealed that approximately 25% of spleen cells were of donor origin, both at short-term (6 weeks) and long-term (greater than 1 year) intervals after tolerance induction. In spite of hematopoietic chimerism, a low incidence of spontaneous tumors, less than 1%, occurred in the long-term survivors.

Light, stratification and zooplankton as controlling factors for the spring development of phytoplankton in Lake Constance

The patterns of phytoplankton growth and decline during the spring bloom and the following clear-water phase in Lake Constance have been studied on the basis of cell counts with short-term sampling intervals and related to light climate, stratification and zooplankton pressure.

Acute effects of selected hepatotoxic agents on polyribosomes and protein synthesis in the livers of rats fed purified diets containing hepatocarcinogens

This investigation was concerned with the effects of certain hepatocarcinogens ingested for long- or short-term intervals upon selected responses of rat liver to specific hepatotoxic stimuli. Rats fed ad libitum for long (3 to 45 weeks) periods or force-fed for short (3 days) periods purified diets containing a single hepatocarcinogen, ethionine, N-2-fluorenylacetamide, 3′-methyl-4-dimethylaminoazobenzene, or thioacetamide, were subjected to the acute administration of a single hepatotoxic agent, such as puromycin, actinomycin D, sparsomycin, hypertonic NaCl or CCl 4, and hepatic protein synthesis ( in vitro) and polyribosomal aggregation were evaluated. Relating to in vitro protein synthesis, in long-term experiments, puromycin induced less inhibition in the experimental groups than in the control (basal diet) group; and actinomycin D inhibited all groups similarly; while in the short-term experiments, puromycin induced less inhibition in the experimental groups than in the control group; actinomycin D inhibited he basal and ethionine groups more than the other groups; sparsomycin induced variable degrees of inhibition, with the ethionine group showing the most and the N-2-fluorenylacetamide and thioacetamide groups showing the least; hypertonic NaCl markedly inhibited all groups similarly; and CCl 4 induced somewhat variable degrees of inhibition, with the thioacetamide group showing less than the other groups. In a few long-term experiments where hepatomas were evaluated in relation to surrounding liver tissue, puromycin administration induced less inhibition in the hepatomas than in the surrounding liver while actinomycin D administration induced similar inhibition in both groups. In general, in all experiments the degree of polyribosomal disagregation was parallel to that of inhibition of protein synthesis ( in vitro). The results reveal that the livers of rats fed purified diets containing selected hepatocarcinogens responded in a variable manner in regard to protein synthesis ( in vitro) and status of polyribosomal aggregation to the acute administration of selected hepatotoxic agents.

Observations on the palaeoecology, population structure and body weight of some Tertiary hominoids

Two empirically based methodologies for estimating primate home range (HR) and population density (D) have been developed, the deriving of such parameters being a function of body weight (BW) or rainfall (RF). Living primate data provide an independent check upon the HR estimates derived from BW for extinct taxa. Such estimates are calculated and considerations of inexactitude discussed for A. zeuxis, P. africanus, R. punjabicus and the Plio-Pleistocene hominids. Palaeoclimatological data indicate that deriving HR and D estimates as a function of RF has significance only for extinct taxa of late Miocene and succeeding times. Such estimates are discussed with reference to the influence of topographic variation and cyclical trends in precipitation patterns over both short and long term intervals. A discrepancy in hominid D estimates is noted between those figures derived from the empirical models investigated and those provided by ethnographic data and direct examination of palaeontologic evidence.

Collection of large quantities of granulocyte/macrophage progenitor cells (CFUc) in man by means of continuous-flow leukapheresis.

Continuous-flow leukapheresis using the AMINCO Celltrifuge was performed in 35 adult volunteers for the procurement of large quantities of granulocyte/macrophage progenitor cells (CFUc) as part of the mononuclear leucocytes. The donor blood volume processed was 12 1 at a flow rate of 50 ml per min. The centrifuge speed was 800 rpm. The mean yield of mononuclear cells (MNC) per run was 12.0 x 10(9) and that of CFUc, 8.7 x 10(5). The leukapheresis did not much affect the donor blood cell concentration except the platelet concentration; this must be considered as a limiting factor for leukapheresis. The mean granulocyte contamination of the leukapheresis-derived leucocytes was only about 10%. Successive leukaphereses (with short-term intervals) in 7 donors led to significant increases in CFUc yield. The possible therapeutic application of blood stem cells in the treatment of haemopoietic failure in man is discussed.

Night-Day Variations of Renin-Activity in Primary Aldosteronism

To detect changes in previously unmeasurable low renin activity plasma specimens of 20 patients with primary aldosteronism (12 with an unilateral adenoma and 8 with idiopathic bilateral adrenal hyperplasia), obtained at short term intervals between 20.00 and 8.00, were incubated over a prolonged period of 18 hours. 6 of 12 patients with an aldosterone producing adenoma (APA) and 3 of 8 patients with idiopathic bilateral adrenal hyperplasia (IAH) showed typical night-day variations of PRA with lower values before and higher values after midnight. 7 of these 9 patients with night-day rhythmicity of PRA simultaneously showed secretory episodes. In 2 patients (1 with APA, 1 with IAH) PRA was constantly undetectable (less than 0.2 ng/ml . 18 h) and in 2 patients with APA a fixed secretion of renin was observed. We failed to demonstrate typical night-day variations of PRA in 3 patients with APA and in 4 with IAH, although in 5 of these 7 patients secretory episodes of PRA were found. Our results show that different patterns of PRA curves may be observed both in patients with APA and IAH. Thus, analysis of PRA curves is of no value to differentiate patients with APA from those with IAH.

Study of protein synthesis in rat liver mitochondria use of cycloheximide.

1. The effects of short-term and long-term administration of cyclohexidine on rat liver mitochondrial protein synthesis have been examined and were found to be different. 2. Long-term administration of cycloheximide resulted in inhibition of total cellular protein synthesis including that of mitochondria while, at short-term intervals, 8-10% of mitochondrial protein synthesis was cycloheximide-resistant. 3. The inhibitory effect was also reflected in terms of protein synthesizing ability of mitochondria in vitro, the inhibition becoming apparent at 40 min and showing progressive increase with time. 4. The observed inhibition of mitochondrial protein synthesis by cycloheximide was not due to either inhibition of energy metabolism or alteration of amino-acid pool. 5. Cycloheximide did not enter mitochondria or sonic preparation under conditions in vitro. On the other hand, after administration of [3H]cycloheximide, significant quantities of the label were found to be associated with mitochondria and mitoribosomes. 6. These results indicated that cycloheximide reached the site of action in mitochondria under conditions in vivo but was unable to do so in vitro. 7. The results are discussed to elucidate the possible mechanisms involved in the inhibition of truly mitochondrial protein synthesis by cyclohexamide.

Repeated plasma cortisol determinations in Cushing's syndrome due to adrenocortical adenoma.

Plasma cortisol determinations were made by a fluorometric method, every 20 min throughout a 24-hr day, in a case of Cushing's syndrome due to an adrenocortical adenoma. Compared with 2 healthy subjects, the patient's curve is set at a higher level, with peaks of less important amplitude. It is concluded that plasma cortisol determinations at short-term intervals are of interest to differentiate adrenal hyperplasia from adrenal adenoma. The real autonomy of adrenal adenoma is to be discovered.