Cardiovascular effects and hemodynamic mechanism of action of the novel, nonpeptidic renin inhibitor A-74273 in dogs

A-74273 is a nonpeptidic, potent inhibitor of human and canine renin (IC50 = 3.1 and 43 nM, respectively, in plasma at pH 7.4) and has been shown to be orally active in dogs. To determine the hemodynamic mechanism underlying this renin inhibitor's hypotensive activity, the cardiac and hemodynamic effects of A-74273 were studied in sodium-depleted and sodium-replete pentobarbital-anesthetized dogs. Vehicle [5% dextrose in water (V, D5W), n = 8] or a single dose of A-74273 was administered intravenously (i.v.) as a bolus followed by a 30-min infusion (one tenth the bolus dose per minute). Baseline mean arterial pressure (MAP) was similar among all treatment groups, but baseline plasma renin activity (PRA) was increased in the sodium-depleted dogs as compared with the sodium-replete dogs. In sodium-depleted dogs (n = 7-8/dose), MAP decreased maximally as compared with baseline by 4 +/- 1, 19 +/- 3, and 23 +/- 3% during infusion of A-74273 at doses of 0.001, 0.01, and 0.1 mg/kg/min, respectively (p < 0.05 vs. baseline or V). The two highest infusion doses also produced significant reductions (p < 0.05 vs. baseline and V) in systemic vascular resistance (SVR, 21 +/- 2 and 25 +/- 2%) and left ventricular end-diastolic pressure (LVEDP, 40 +/- 8 and 47 +/- 12%). In sodium-replete dogs (n = 4/dose), an infusion dose of 0.01 mg/kg/min elicited no hemodynamic response, whereas 0.1 mg/kg/min reduced MAP by 13 +/- 2% (p < 0.05 vs. baseline) and SVR by 7 +/- 6%.(ABSTRACT TRUNCATED AT 250 WORDS)

Discovery of a well-absorbed, efficacious renin inhibitor, A-74273

The development of orally active renin inhibitors has been plagued by limited bioavailability in animals and humans. A-74273 is a novel, potent nonpeptide inhibitor of human renin (IC50 = 3.1 nM). This compound was absorbed into the portal and systemic circulations of anesthetized rats, ferrets, monkeys, and dogs after intraduodenal dosing. This favorable pattern also was observed after oral dosing in conscious animals, except in monkeys. Hepatic extraction of A-74273 was more efficient in rats and monkeys than in dogs or ferrets. A-74273 modestly inhibits dog renin, and when given orally as the base (0, 0.3, 1, 3, 10, and 30 mg/kg; n = 8 per dose) to conscious, salt-depleted dogs it induced dose-related reductions in mean arterial pressure and plasma renin activity. Peak falls in mean arterial pressure from normotensive baselines were -14 +/- 1, -26 +/- 3, and -44 +/- 3 mm Hg for the 3, 10, and 30 mg/kg groups, respectively (p < 0.05). Baseline plasma renin activity values (10.9 +/- 1.1-12.7 +/- 1.1 ng angiotensin I/ml/hr) were maximally inhibited, ranging from 43 +/- 8% at 0.3 mg/kg to 98 +/- 1% at 30 mg/kg. Bioavailability in this model was estimated to be 54 +/- 13% when plasma drug levels were determined by a renin inhibitory activity assay, but bioavailability was lower when compared with high-performance liquid chromatographic analysis of A-74273. This discrepancy was accounted for by the identification of structurally similar metabolites that are as active as the parent drug against human renin but much less potent against dog renin.(ABSTRACT TRUNCATED AT 250 WORDS)

Discovery of a peptide-based renin inhibitor with oral bioavailability and efficacy

Peptidic renin inhibitors have been poorly absorbed across the intestine or rapidly eliminated by the liver and have been reported to have oral bioavailabilities of less than 2%. A peptide-based renin inhibitor, A-72517 (molecular mass of 706 daltons), was devised that has oral bioavailabilities of 8, 24, 32, and 53% in the monkey, rat, ferret, and dog, respectively. Dose-related reductions in blood pressure, plasma renin activity, and plasma angiotensin II in parallel with increased plasma drug concentrations were observed after oral administration of A-72517 to conscious, salt-depleted dogs. Thus, peptide-based molecules of sizable molecular mass can be absorbed intact into the systemic circulation of animals. These findings support the potential of peptide-based drugs for oral administration.

Double-blind comparison of patient recovery after induction with propofol or thiopentone for day-case relaxant general anaesthesia

Postoperative recovery after induction with either propofol or thiopentone has been compared in forty ASA I unpremedicated day surgery patients undergoing surgical extraction of third molar teeth under relaxant general anaesthesia. Mean recovery times in the propofol group, required for patients to sit out of bed (44.8 minutes; SD 18.6) and meet discharge criteria (113.1 minutes; SD 34.5) were significantly (P less than 0.05) shorter than those in the thiopentone group (59.7 minutes; SD 21.4 and 133.5 minutes; SD 34.5). Fewer patients in the propofol group were treated in the recovery room for nausea and vomiting and the incidence of mild nausea not requiring treatment was less in the propofol group, but these differences were not statistically significant. Postoperative mental performance, measured by the FAST index, a new test of mental speed, was reduced on average by 1.7% of preoperative levels, during the recovery period tested, with no significant difference between the groups.

Monozygotic twins with seizures. Shared characteristics

Eleven sets of monozygotic twins with idiopathic seizure disorders seen at Children's Hospital, Boston, Mass, were reviewed Nine twin pairs were concordant for seizures. A marked correlation in the precise timing of onset of seizures was found; three sets of twins had their first clinical seizures within a 24-hour period of one another. The clinical features of the seizures and the electroencephalographic patterns, including the location of focal discharges, were strikingly similar in the twin pairs. The significance of these findings in suggesting aberrant processes that may contribute to epileptic syndromes is discussed.

Patient satisfaction among the residential population of a psychiatric hospital

Patient satisfaction with the interpersonal and amenities aspects of care in a psychiatric hospital was investigated in an Australian setting. The study was carried out among the long-term residential population of a psychiatric hospital and involved 112 out of 195, or 57% of all eligible patients. Cluster analysis identified seven major groups of related items concerning the patients' views of hospital life and their perception of problems. The study largely replicated the findings of an English investigation, showing that many of the same underlying clusters of satisfaction-dissatisfaction with life in a psychiatric hospital emerge, across widely geographically separated settings. The results from the present study further indicate that improvements in autonomy for the patients and a greater say in the running of wards are more important factors contributing to satisfaction with life in a hospital than the physical surroundings themselves.

Diagnostic coding quality and its impact on healthcare reimbursement: research prospectives

This article reviews research on the sources of coding errors and summarizes the findings. It presents a research model and justification for experimental research to measure the factors affecting the sources of coding error and the potential impact these factors have on coding quality and subsequent reimbursement levels.

Neonatal cilia: ultrastructure

The number of inner and outer dynein arms and gross cilial abnormalities of well newborn children and adults were similar. Inability to see all nine outer dynein arms in healthy adults may be due to technique and not recent infection or congenital cilial malformation.

Bulimia: independence of antibulimic and antidepressant properties of desipramine

The purpose of this study was to identify variables useful for predicting a positive response to the tricyclic antidepressant desipramine, amongst bulimic subjects. Using a randomized double-blind cross-over design, 24 normal weight bulimics completed a 15-week protocol in which they received either desipramine (150 mg/day) for six weeks, no drug for three weeks, followed by placebo for six weeks, or the reverse sequence. At weeks 0, 2, 4, 6, 9, 11, 13, and 15, each subject was assessed using the EDI, SCL-90, POMS and binge records. The DST, Diagnostic Interview Schedule (DIS), and a personal and family medical-psychiatric history questionnaire were administered at initial assessment, while plasma desipramine levels were obtained at weeks 4 and 13. Responders were defined in terms of both binge frequency reduction, and decrease in depressive symptoms. In the sample of 24 subjects, desipramine was significantly more effective than placebo in reducing the frequency of weekly binging and vomiting, as well as causing a reduction in the fatigue scale of the POMS. No significant effect of the drug was obtained on the EDI or the SCL-90. In terms of reduction in binge frequency, seven responders were identified; another seven were found to be borderline responders, while 10 were labeled as non-responders. The three groups did not differ in terms of their initial scores on the SCL-90, POMS, DST, DIS results, or psychological subscales of the EDI. However, responders were found to have lower EDI bulimia subscale scores, but a higher frequency of purging episodes than were non-responders. Eight patients were identified as borderline responders with respect to depressive symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Whole body and regional fuel metabolism during early postexercise recovery

We studied whole body and regional fuel metabolism 1-4 h after cycle exercise [70% maximum O2 consumption (VO2max)], using the insulin clamp technique (40 mU.M-2.min-1) with indirect calorimetry. Substrate fluxes were determined in nonexercised (forearm) muscle tissues. Total glucose utilization was not increased by exercise, either in the preinsulin or insulin-stimulated state. Glucose oxidation tended to decrease, and lipid oxidation was increased after exercise. Forearm glucose uptake (FGU) was increased 5 times by insulin in the resting state, due largely to increased fractional extraction (P less than 0.05). After exercise, FGU was not increased by insulin. Forearm alanine and lactate release was doubled 2 h after exercise. Branched-chain amino acid (BCAA) concentrations were increasing after exercise (P less than 0.01) at a time when forearm muscle was taking up these amino acids. Insulin infusion suppressed the elevated release of gluconeogenic precursors from the forearm and suppressed the elevated concentrations of BCAAs, free fatty acids, and glycerol present after exercise. In summary, basal and insulin-stimulated glucose utilization is not augmented by prior high-intensity exercise, partly because nonexercised muscle is insulin resistant. Insulin infusion attenuates the altered metabolic milieu seen during early recovery.

A focused casework approach to the treatment of child abuse: a controlled comparison

Two contrasting therapies for the treatment of child abuse were compared in a randomised design: a focused casework approach to the whole family and a structured play therapy approach to the child. The Patterson coding system was used as an outcome measure. There was a high drop-out rate from both the therapies, but of those who completed the treatment, there was a greater improvement in the focused casework regime on some of the comparisons made.

Treatment of bulimia with desipramine: a double-blind crossover study

The purpose of this study was to evaluate the effect of desipramine, a tricyclic antidepressant with relatively specific noradrenergic effects, on bulimic behaviour, eating attitudes, and mood. Using a double-blind crossover design, 47 normal weight bulimics were randomly assigned to receive either desipramine (150 mg/day) for six weeks, no drug for three weeks, followed by placebo for six weeks, or the reverse sequence. At weeks 0, 2, 4, 6, 9, 11, 13, and 15, each subject was assessed using the EDI, SCL-90, POMS and binge records. Plasma desipramine levels were obtained at weeks 4 and 13. Twenty-four subjects completed the entire fifteen week protocol, while 23 dropped out. Desipramine was significantly more effective than placebo in reducing the frequency of weekly binding, weekly vomiting, and the fatigue scale of the POMS. No significant effect of the drug was obtained on the EDI or the SCL-90. The clinical effect was modest. Desipramine's antibulimic effects were not associated with an alleviation of depressive symptoms.

Immunological detection of myeloperoxidase in synovial fluid from patients with rheumatoid arthritis

We have used rocket immunoelectrophoresis and immunoblotting to detect myeloperoxidase in synovial fluid from patients with rheumatoid arthritis. This protein was enzymatically inactive but its identity as myeloperoxidase was confirmed by comparing its subunit structure with that of the purified enzyme. When neutrophils were stimulated to secrete myeloperoxidase in vitro, a polypeptide with an apparent molecular mass of 62 kDa was detected extracellularly by immunoblotting. Neutrophils isolated from synovial fluid showed a reduced level of this 62 kDa polypeptide but it was detected extracellularly in synovial fluid by immunoblotting. Thus, we conclude that neutrophils in synovial fluid from patients with rheumatoid arthritis have been activated in vivo to secrete myeloperoxidase and propose that the products of this enzyme system can contribute to the tissue damage associated with this disease.

Echocardiographic and hemodynamic correlates of diastolic closure of mitral valve and diastolic opening of aortic valve in severe aortic regurgitation

Acute severe aortic regurgitation (AR) is characterized by a steep increase in left ventricular end-diastolic pressure, exceeding left atrial pressure and occasionally equilibrating with aortic diastolic pressure. These pressure phenomena correlate with the M-mode echocardiographic (echo) findings of diastolic closure of the mitral valve (DCMV) and diastolic opening of the aortic valve (DOAV). Six men, aged 23 to 48 years, with recent-onset, severe AR were evaluated by M-mode echo and pressures at cardiac catheterization. DCMV was seen in all 6 patients and DOAV in 4. Near-constant time intervals from the preceding R wave of the electrocardiogram to DCMV and DOAV were seen, even in 3 patients with varying RR intervals (1 with atrial fibrillation and 2 with asynchronous and demand atrial pacing). When the RR intervals were shorter than these intervals, DCMV and DOAV did not occur. Increasing the heart rate in the 2 patients by atrial pacing resulted in a marked decrease in left ventricular end-diastolic pressure. In conclusion, DCMV and DOAV have a near constant relation to the preceding R wave of the electrocardiogram, DCMV with competence of the mitral valve must be present for DOAV to occur, DOAV indicates that the diastolic blood pressure equals left ventricular end-diastolic pressure, and heart rate is an important factor influencing the hemodynamic and echocardiographic parameters in recent-onset, severe AR.

Energy malabsorption: measurement and nutritional consequences

Fecal energy (FE) loss was measured using bomb calorimetry in 30 patients; 14 had a history of malabsorption, while 16 had no history of intestinal dysfunction. Average digestibility (and range) of energy and FE loss were 73% (48 to 91%) and 493 kcal/day (177 to 927 kcal/day) in the group with malabsorption, compared to 96% (89 to 99%) and 74 kcal/day (8 to 146 kcal/day) in the group without malabsorption, respectively. Metabolizable energy supplied by the diet (intake kcal -- (fecal kcal + urinary kcal) was below the calculated daily energy requirement in five of seven patients with malabsorption; in three of these five subjects the combination of decreased energy intake and increased FE loss produced negative energy balance, while in the remaining two patients malabsorption alone caused negative energy balance. Inadequate metabolizable energy in these five patients was associated with weight loss and protein-energy malnutrition. The usual clinical laboratory tests applied to the study of malabsorption, including fecal fat, fecal nitrogen, and stool weight, were poor predictors of FE loss. These tests were also of limited value in assessing the effects of dietary modification on energy malabsorption. Contrastingly, bomb calorimetry provided a simple and accurate alternative in quantitatively assessing FE loss in the patient with malabsorption.

Ultrastructural changes accompanying the growth of isolated oligodendrocytes

The changes in the ultrastructure of oligodendrocytes with time in culture were examined by transmission electron microscopy. Oligodendrocytes were isolated from ovine white matter and maintained in Dulbecco's modified Eagle's medium supplemented with 20% horse serum. One day after being placed in plastic culture dishes, most cells aggregate into clusters that do not attach to the surface for several days. Cells within these clusters form junctional complexes resembling gap junctions, their nuclear chromatin becomes uniformly dispersed, they are rich in polyribosomes, and their cytoplasm is less osmiophilic than oligodendrocytes in ovine white matter or cells fixed immediately after isolation. After several days in culture, the cells become attached to the plastic surface, chromatin once again becomes clumped beneath the nuclear membrane, rough endoplasmic reticulum accumulates within the cytoplasm and the cells extend long processes containing cytoplasmic organelles. From these observations, it appears that oligodendrocytes undergo a transient dedifferentiation during their recovery from the trauma of isolation, not unlike the central chromatolysis seen in neurons following axonal injury. After acclimatization to tissue culture conditions, isolated oligodendrocytes show many of the morphologic features seen in vivo and therefore offer a good model to study myelination.

Weekly cis-diamminedichloroplatinum(II): active third-line chemotherapy in ovarian carcinoma--a preliminary report

Ten evaluable patients with progressive ovarian adenocarcinoma received third-line chemotherapy consisting of weekly cisplatin (cis-diamminedichloroplatinum[II]) at a dose of 1 mg/kg weekly for a maximum of 6 weeks followed by 60 mg/m2 every 3 weeks. There was no life-threatening toxicity. Seven patients (70%) achieved an objective partial response. This is the highest response rate achieved, to date, by third-line chemotherapy in women with advanced ovarian adenocarcinoma. Weekly cisplatin therefore warrants a trial as first-line therapy.

Metabolic effects of human growth hormone and of estrogens in boys with Duchenne muscular dystrophy

Metabolic balance studies were conducted in seven boys with Duchenne-type muscular dystrophy, and in six normal boys of similar age, during a 12 day control period and during a 12 day period of treatment with human growth hormone (HGH) at the following doses: 0.0168, 0.0532, and 0.168 U/kg body weight (BW)((3/4)) per day (doses A, B, and C, respectively). In five of the six normals, dose C caused positive balances in N, P, Na, and K; doses B and A had anabolic effects in two and one normal subjects, respectively. In six of the seven Duchenne cases, dose C caused negative balances of N and K, and sometimes of P. Negative balances were produced in three of the Duchenne subjects by dose B, and in one by dose A. None of the dystrophy cases exhibited an anabolic response to any dosage of HGH tested. The release of endogenous HGH in response to insulin, after 2 days' pretreatment with diethylstilbestrol, was similar in both groups of subjects. In the course of these tests, a marked anabolic effect of diethylstilbestrol in the Duchenne patients was apparent. Therefore metabolic balance studies were repeated, in both Duchenne and normal cases, during a 12 day control period and during 12 days of treatment with diethylstilbestrol (0.106 mg/kg BW((3/4)) per day). In three of the normal children, diethylstilbestrol had no effect on the elemental balances; in two cases, a retention of Na was observed. In all seven Duchenne cases, diethylstilbestrol caused positive balances in N, P, Na, and K. Ethinyl estradiol (0.0106 mg/kg BW((3/4)) per day) produced positive N, P, Na, and K balances in all three Duchenne cases tested with this agent. The data show that exogenous HGH causes a catabolic effect in boys with Duchenne dystrophy. These patients are hyperresponsive to the anabolic effect of diethylstilbestrol. The latter phenomenon may reflect the inhibitory effect of estrogen upon the peripheral actions of these boys' endogenous HGH.

Observations on the responsiveness of human subjects to human growth hormone. Effects of endogenous growth hormone deficiency and myotinic dystrophy

The effect of human growth hormone (HGH) on the N, P, Na, and K balance, and on the body weight (BW) of three groups of subjects was measured. In group I were nine cases (age 6-69) with HGH deficiency; in group II, eight cases (age 9-79) with normal endogenous HGH; in group III, four cases with myotonic dystrophy (age 45-51). After a 7 day control period, the hormone was administered for 7 days. Each subject was tested with three doses of HGH: dose A, 0.0168 U/kg BW(3/4) per day; dose B, 0.0532 U/kg BW(3/4) per day; dose C, 0.168 U/kg BW(3/4) per day. In group I, the responsiveness to HGH declined with age. Two subjects aged 6 yr responded to all three doses of HGH with positive balances in N, P, Na, and K and increases in BW. At ages 15-17, responses were obtained only to doses B and C in three cases, and only to dose C in two cases. Two subjects, aged 42 and 69, responded only to dose C. Not only did the threshold dose increase with age in group I, but the magnitude of the responses declined with age as well.Patients of group II were less responsive to all doses of HGH than were patients of group I at comparable age. None responded to dose A or dose B. All responded to dose C, but the increments in balances and in BW stimulated by this dose were only one-third to one-half as great as in HGH-deficient subjects of similar age. Three patients of group III responded to all three doses of HGH, and one responded to doses B and C. The responses were similar in magnitude to those in the 6-yr old HGH-deficient children, and greater than those in all other subjects studied. These data show that responsiveness to exogenous HGH rises with deficiency of endogenous HGH, and that individuals with myotonic dystrophy are hyperresponsive to exogenous HGH.

Polymorphisms of Esterase Isozymes in the American Lobster (Homarus americanus)

Five groups of esterase active bands were found after electrophoretic separation of extracts of heart tissue of lobsters (Homarus americanus) on starch gels. Each group consisted of one or more bands that were distinguishable from other groups by their electrophoretic mobility, substrate specificity, and susceptibility to various inhibitors. Groups designated I–IV are carboxylesterases; group V is a cholinesterase. Individual variations were observed in groups I, II, and V. The observed polymorphisms in groups I and II were hypothesized as due to codominant allelic systems. The phenotypic frequencies of group I isozymes observed in two populations agreed well with the Hardy–Weinberg distributions expected for such systems. The frequencies of variant types in group II were too low for meaningful population genetic analysis. Phenotype frequencies were not correlated with sex, size of the carapace, or stage of the molt cycle. Developmental changes of esterase isozymes were observed during the first eight stages. The Es-V (cholinesterase) group and Es-II groups were present at hatching, but the Es-I group was not clearly observed until after the seventh molt. Phenotype ratios of offspring from single females supported the genetic hypothesis for the Es-I system.

Changes in Serum Protein During the Molt and Reproductive Cycles of the American Lobster (Homarus americanus)

The variations in the serum proteins of lobsters were studied by quantitative protein determinations, starch gel and cellulose acetate electrophoresis, and immunodiffusion. A series of bleedings from 15 lobsters provided serum samples for each stage of the molt cycle. Total serum protein was highest before the molt and lowest directly after the molt. The total serum protein averaged 2.5 g/100 ml in the intermolt lobsters and variation among individuals was limited. Variation of serum proteins in an individual during the molt cycle included changes in the electrophoretic and immunodiffusion pattern. Quantitative changes during the cycle indicate a relative shift in the concentrations of various proteins. One component of serum protein was associated only with the development of eggs and another component was present only during premolt and directly after molt.

Distinctive features in the pluralization rules of English speakers

First and second graders, given CVC singulars (e.g., NAR) orally and asked to choose between two plurals (NARF-NARK), preferred final sounds sharing with /z/ the stridency or continuance features. This suggests that their pluralization rules are formulated in terms of distinctive features rather than sound segments. Kindergarten children and adults showed no such preferences.