Precocious in vitro development of satellite cells from dystrophic chicken muscle.

Satellite cells, liberated from pectoral muscle of juvenile dystrophic chickens by sequential treatment with collagenase, hyaluronidase, and trypsin and preplated to remove fibroblasts and cultured on gelatin proliferated rapidly, fused and formed confluent muscle cultures within 6 d in vitro with minimal contamination by fibroblasts. When identical isolation and culturing techniques were applied to muscle from age-matched normal chickens proliferation and differentiation were slower, contamination with fibroblasts was much greater, and only a small number of myotubes were formed. After injection of the myotoxic anesthetic marcaine into normal pectoral muscle for 5 consecutive days, myotube formation was accelerated in satellite cell cultures, but the rate of differentiation was not as rapid as that occurring in cells from dystrophic muscle.

Posture-independent sensorimotor analysis of inter-hemispheric receptor asymmetries in neostriatum.

Nigrostriatal dopaminergic neurons are thought to be critically important for somato-sensorimotor behavior. Following unilateral irreversible elimination of these neurons, an animal shows an ipsiversive postural bias and permanently fails to orient its head toward tactile stimuli placed on the contralateral side of the body. In response to apomorphine, a dopamine agonist, these rats display contraversive circling.

Acute cranial polyneuritis with vertigo after stapedectomy.

Acute vertigo occurring 48 hours after stapedectomy is assumed to be related to inner ear trauma. Similarly, acute vertigo occurring weeks after stapedectomy could be related to a fistula of the oval window. No one has tested the hypothesis that some of these cases could represent concomitant cranial polyneuritis.

Reversal of morphine-induced catalepsy by naloxone microinjections into brain regions with high opiate receptor binding: a preliminary report.

The relationship between opiate binding density and morphine-induced catalepsy was estimated via dose-response analysis of the brain sites in which naloxone microinjections reversed the catalepsy induced by intraperitoneal morphine. One-hundred forty-one experimentally naive male Long-Evans rats were implanted with chemical microinjection guide cannulae aimed for various high-to-moderate binding density areas within caudate nucleus, central gray matter, thalamus, hypothalamus, amygdala, and frontal cortex as well as low density sites in pyriform cortex and various fiber tracts. Overall, 48 out of 91 animals microinjected with naloxone in brain sites having high-to-moderate density of opiate binding showed reversal of the cataleptic response.

Is exercise good for high blood pressure?

Ten men with uncomplicated essential hypertension (mean standing blood pressure 165/109 mm Hg) and 10 normal controls matched for age and weight were studied for the hypotensive potential of moderate exercise. Tests were conducted on a treadmill set to induce a steady heart rate of 120 beats/min and performed over five 10-minute periods separated by three minutes' rest and finishing with 30 minutes' sitting quietly in a chair.During exercise the mean systolic pressures were identical in the hypertensive patients and controls (175+/-SEM 5 mm Hg), the controls therefore sustaining an appreciably greater increase in pressure.

Comparison between atenolol and nadolol in essential hypertension at rest and on exercise.

1 The effects of 4 week treatment periods of once-daily atenolol 100 mg, nadolol 80 mg, nadolol 160 mg and placebo on resting and exercise heart rate and blood pressure were compared in a single-blind crossover trial in fifteen patients with essential hypertension. 2 Both atenolol and nadolol, irrespective of dose, reduced resting and exercise blood pressures to the same extent. 3 Nadolol caused a greater bradycardia both at rest and during exercise than did atenolol, thereby effecting a greater reduction in double-product.

Dopamine receptor sensitivity after chronic dopamine agonists. Striatal 3H-spiroperidol binding in mice after chronic administration of high doses of apomorphine, N-n-propylnorapomorphine and dextroamphetamine.

Several previous reports have demonstrated that chronic administration of both directly and indirectly acting dopamine agonists produces a supersensitive behavioral response to challenge doses of dopamine agonists when compared to the responses induced by acute administration of these drugs. That is, a given dose of a dopamine agonist will produce a greater response after chronic dopamine agonist treatment than is observed upon acute administration of that dose. A similar behavioral phenomenon resulting from chronic administration of dopamine antagonists has been suggested to be due to an increase in the number of dopamine receptors present in relevant brain areas.

Comparative study of atenolol, metoprolol, metoprolol durules, and slow-release oxprenolol in essential hypertension.

Twenty-five patients with moderate essential hypertension (standing diastolic blood pressure 100-125 mmHg, phase 5) completed a single-blind placebo-controlled cross-over study comparing four week periods of treatment with atenolol 100 mg, metoprolol 100 mg, metoprolol durules 200 mg, slow-release oxprenolol 160 mg, and slow-release oxprenolol 320 mg respectively. All the drugs were significantly better than placebo at reducing resting blood pressure at 24 hours. Atenolol produced the greatest mean reduction of pressure and was the most effective drug for most patients, though the differences between atenolol and metoprolol durules were not statistically significant.

Apomorphine: bioavailability and effect on stereotyped cage climbing in mice.

Plasma levels fo apomorphine and its conjugates were studied following intravenous, intraperitoneal, and oral administrations to mice. Following hydrolysis, apomorphine and its conjugates were assayed by high-performance liquid chromatography. The absolute bioavailability of apomorphine was 4%.

Prognosis of patients with "chest pain ?cause".

All 662 patients admitted to the two coronary care units in Nottingham during 12 consecutive months were followed up prospectively for one year. At the time of discharge from hospital they were categorised according to set criteria into the following diagnostic groups: definite, probable, or possible myocardial infarction; ischaemia heart disease without infarction; chest pain ?cause; and other diagnoses. Eighty-nine patients (13% of admissions) were categorised as having chest pain ?cause.

Effects of apomorphine and piribedil on pentylenetetrazol-induced seizures in mice.

Based on previous work examining the effects of dextroamphetamine on pentylenetetrazol (PTZ)-induced clonic seizure threshold, the objective of the present study was to determine the effects of two other dopamine agonists, apomorphine (AP) and piribedil, on PTZ seizures. TD50 and LD50 values for CD-1 mice were determined initially for the two drugs. Subsequently, dose- and time-response analyses established that AP decreased PTZ seizure threshold 15 min after administraton, but increased the threshold at 60 min.

Acute intervention studies in patients with myocardial infarction using atenolol, propranolol, oxprenolol and disopyramide phosphate.

The value of beta-blockade and of disopyramide phosphate in the immediate treatment of patients with suspected acute myocardial infarction was assessed in two placebo controlled trials. In the first study 388 patients with suspected acute myocardial infarction were randomly allocated to treatment with propranolol, atenolol, or placebo, and when analysed on an initial intention to treat basis there was no significant difference between the three groups in respect of the mortality at one year. In addition, there was no evidence to suggest that either atenolol, or propranolol reduced the incidence of 'serious' ventricular arrhythmias in the coronary care unit.

Importance of age in prehospital and hospital mortality of heart attacks.

Prehospital and hospital fatality rates were calculated for each 10-year age group of 2788 patients transported to hospital with heart attacks. The prehospital fatality rate rose progressively from 4 per cent in the youngest age group to 45 per cent in the oldest. There was no age-related difference between the groups in the interval between the onset of symptoms and the first call for help, and a similar proportion of each group summoned a general practitioner.

Randomised placebo-controlled trial comparing oxprenolol with disopyramide phosphate in immediate treatment of suspected myocardial infarction.

473 patients with suspected acute myocardial infarction were entered into a randomised, double-blind, placebo-controlled comparison of disopyramide phosphate, 150 mg three times a day, and oxprenolol, 40 mg three times a day. When analysed on an intension-to-treat basis there was no significant difference in 6-week mortality between the groups, but patients who were able to continue on the active medications fared better than the patients who had to be withdrawn. The withdrawal rate because of heart failure in patients randomised to receive disopyramide was significantly increased.

Cardiovascular reflexes in patients after myocardial infarction. Effect of long-term treatment with beta-adrenoceptor antagonists.

A double-blind study was made of men who had had a myocardial infarction at least one year previously, and who were being treated with propranolol, atenolol, or placebo. They were compared with age- and sex-matched control subjects. Under resting conditions, there were no differences between the systemic arterial blood pressures, forearm blood flows, or heart rates of the control subjects and the post-infarction patients treated with placebo.

Sulphinpyrazone in acute myocardial infarction: studies on cardiac rhythm and renal function.

Ninety-eight patients with acute myocardial infarction were randomly allocated to receive sulphinpyrazone 200 mg four times daily or placebo on admission to a coronary care unit. Twenty-four-hour electrocardiogram tape recordings showed no significant reduction in serious arrhythmias in the sulphinpyrazone-treated group. In addition to the expected all in serum urate concentration, patients taking sulphinpyrazone showed a persistent increase in their serum urea and creatinine concentrations when compared with those in the placebo groups (p < 0.

Polydimethylsiloxane pellets for sustained delivery of morphine in mice.

A new dosage form was designed whereby a polymeric silicone elastomer provided sustained delivery of morphine to mice over 11 days. These pellets, which can be made easily and inexpensively with a standard tablet mold, gradually released morphine sulfate into the implanted mice. Maximal morphine-induced physical dependence, measured by jumping during naloxone-induced withdrawal, was observed 3--5 days after implantation.

Stability of apomorphine in solutions containing ascorbic acid and bisulfite and effects of antioxidants on apomorphine-induced cage climbing and hypothermia in mice.

Ascorbic acid (100 mg/ml) and sodium bisulfite (0.5 and 20 mg/ml) prevented more than 10% oxidation of apomorphine hydrochloride in water maintained at room temperature over 1-3 days. Refrigeration at 5 degrees prevented oxidation of apomorphine hydrochloride in aqueous solutions for 1 week.

Strain differences in dopamine receptor function and the initiation of movement.

The relationship between voluntary movement initiation (VMI) and caudate nucleus dopamine receptor dynamics was analyzed in two rat strains. Charles River CD/F F-344 (CR-CD/F) and Zivic-Miller CD (ZM-CD) rats (male, 125-150 g) were trained to rapidly release and reset a response lever to avoid electric shock. Whereas 86% of all CR-CD/Fs completed training, only 43% of the ZM-CDs were able to do so.

Randomised trial comparing propranolol with atenolol in immediate treatment of suspected myocardial infarction.

The value of beta-blockade for suspected acute myocardial infarction was assessed by determining the six-week and one-year mortality rates in patients started on propranolol, atenolol, or placebo immediately on entry to a coronary care unit. A total of 388 patients entered this double-blind, randomised study, and when analysed on the basis of the initial, intention-to-treat categories there was no significant difference between the three groups in respect of the mortality rate at one year. There was, however, a high withdrawal rate from the trial; the reasons for this illustrate problems of physician compliance and interpretation of data, which are common to all early-entry trials of haemodynamically active agents in acute myocardial infarction.

Acute and chronic effects of barbituartes on depolarization-induced calcium influx into rat synaptosomes.

Depolarization-induced 45Ca2+ influx into synaptosomes isolated from nontreated control and acutely treated rats (given 60 mg/kg phenobarbital i.p.) was significantly depressed (54 and 37%, respectively) by an in vitro challenge with pentobarbital, 0.

Ménière's disease as a form of cranial polyganglionitis.

Although endolymphatic hydrops is generally considered to be the most prominent factor in the etiology and pathology of Ménière's disease, we have concluded that this condition more probably represents a polyganglionitis caused by the herpes simplex virus with secondary hydrops changes. The wide range of symptoms occurring in the Ménière's disease complex is illustrated in seven selected cases which support this conclusion. Vestibular nerve section can stabilize hearing and relieve episodic vertigo by removing the locus of viral infection and precluding recurrent activation.