Eight-year follow-up study of bromocriptine monotherapy for Parkinson's disease

An 8-year nationwide study of bromocriptine monotherapy and combination therapy with bromocriptine and levodopa in Parkinson's disease is reported. Fifteen patients were on bromocriptine monotherapy, and 44 patients on bromocriptine combined with levodopa for a certain time during an 8-year period. By judging from Hoehn and Yahr's grading, 4 of the 15 patients in the monotherapy group were in a better condition than before treatment, while 7 cases remained in the same grading, and only 4 showed deterioration. On the other hand, 26 of 44 patients on combination therapy showed more advanced grading at the end of 8 years compared to the stage at the onset of the trial. Maintenance doses of bromocriptine in the two groups were 12-13 mg per day, and levodopa doses were kept at a relatively low level (310-370 mg per day) during this study period. Whether dopamine receptor agonists have neuroprotective effect or not is extremely difficult to prove in human subjects, but this type of long-term follow-up study might give some clues as to these important questions.

Combined effects of cabergoline and L-dopa on parkinsonism in MPTP-treated cynomolgus monkeys

The behavioral effects of L-dopa or cabergoline alone were compared with those of the joint administration of the two drugs in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys with attention to the induction of hyperactivity and dyskinesia. Cabergoline alone at 0.2 mg/kg or less improved in a dose-dependent fashion the parkinsonism without inducing hyperactivity and dyskinesia following a single subcutaneous injection. L-dopa alone improved the parkinsonism, but induced hyperactivity and dyskinesia, depending on the dose applied. Doses required for 50% amelioration by L-dopa and cabergoline were 10 and 0.038 mg/kg, s.c., respectively. With low doses (50%-amelioration doses), cabergoline or L-dopa alone improved the parkinsonism without induction of hyperactivity and dyskinesia, but the duration of action was brief. Cabergoline in combination with L-dopa was highly effective in improving motor disability without induction of hyperactivity and dyskinesia. Moreover, the duration of action was more prolonged with the coadministration than with the single administration of each drug. These findings suggest that the combined therapy with low doses of L-dopa and cabergoline is beneficial for treating patients with advanced Parkinson's disease.

Glycemic control, growth and complications in children with insulin-dependent diabetes mellitus--a study of children enrolled in a Summer camp program for diabetics in Kinki district, Japan

The influence of glycemic control on growth and on the development of complications in diabetic children was studied. The subjects of the study were 107 children with insulin-dependent diabetes mellitus (IDDM), who were enrolled in a Summer camp program for diabetic children in Kinki District, Japan from 1972 to 1990, and who had at least three determinations of HbA1 during the observation period. Many of the children had high mean levels of HbA1, regardless of age. The height and weight were below the standards for the respective ages in many children, indicating the retardation of growth. However, S.D. scores for height and weight and other physical indices were not related to the mean levels of HbA1. By contrast, the prevalence of diabetic retinopathy was related to an elevated mean level of HbA1, but that of albuminuria was not. Serum cholesterol levels were higher in children with higher mean levels of HbA1, but serum triglycerides appeared not to be related to glycemic control. The incidence of retinopathy during the observation period closely related to the degree of the mean levels of HbA1, but that of albuminuria did not.

Somatic mosaicism of CAG repeat in dentatorubral-pallidoluysian atrophy (DRPLA)

An unstable expansion of CAG repeat in the coding region of the DRPLA gene on chromosome 12p is the mutation specific for hereditary dentatorubral-pallidoluysian atrophy (DRPLA). We studied the CAG expansion in brain and other tissues from six unrelated DRPLA patients. The CAG repeat lengths showed distinct differences between tissues. The sizes of the CAG expansion in various regions of the brain except the cerebellum were generally larger by several repeats than in other peripheral tissues. Brain samples showed greater variation of the expansion compared with other tissues, but neither the size of the CAG expansion nor the degree of CAG repeat variation parallels the detailed findings of neuropathological involvement. We conclude that somatic instabilities of the CAG repeat cause tissue variability of the CAG repeat size in DRPLA but other region or cell type-specific factors would be involved to explain the selectivity of cell damage in DRPLA.

Combination treatment of the partial D2 agonist terguride with the D1 agonist SKF 82958 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned parkinsonian cynomolgus monkeys

The optimal combination of a dopamine D2 agonist and a D1 agonist was evaluated for symptomatic treatment of Parkinson's disease. Behavioral effects of combination treatment of the full D2 agonist quinpirole or the partial D2 agonist terguride with the full D1 agonist SKF 82958 [(I) 6-Chloro-7, 8-dihydroxy-3-allyl-1-phenyl-2, 3, 4, 5-tetra-hydro-1H-3-benzazepine] were investigated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys with attention to the induction of hyperactivity such as irritability, excitability and aggressiveness and of dyskinesias such as licking of paws, chewing and biting. Both quinpirole and SKF 82958 alone improved the parkinsonism with a slight induction of the hyperactivity and dyskinesias. Terguride also improved the parkinsonism but did not induce the hyperactivity and dyskinesias. Combination treatment of quinpirole with SKF 82958 not only showed a tendency to augment the antiparkinsonian effects but also induced the marked hyperactivity and dyskinesias. On the other hand, combination treatment of terguride with SKF 82958 also augmented the antiparkinsonian effects but did not induce any hyperactivity and dyskinesias. These findings suggest that combination therapy with a partial D2 agonist and a full D1 agonist or monotherapy with a dopamine agonist that has both partial D2 and full D1 agonist properties might be beneficial for treating motor dysfunction in Parkinson's disease without inducing dopaminergic side effects.

Behavioral involvement of central dopamine D1 and D2 receptors in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys

To clarify the roles of dopamine D1 and D2 receptors in behavioral symptoms of Parkinson's disease, antiparkinsonian effects of various dopamine agonists in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian monkeys were investigated with regard to induction of hyperactivity such as excitability, irritability and aggressiveness. The non-selective dopamine agonist apomorphine ameliorated the parkinsonism, but induced marked hyperactivity dose-dependently. Pretreatment with either the dopamine D1 antagonist SCH 23390 or the dopamine D2 antagonist sulpiride markedly suppressed the apomorphine-induced hyperactivity with slight attenuation of the antiparkinsonian effects. Both the dopamine D2-receptor agonist quinpirole and the dopamine D1-receptor agonist SKF 82958 ameliorated the parkinsonism in a dose-dependent manner with a slight induction of hyperactivity. Combination treatment of a threshold dose of quinpirole with that of SKF 82958 augmented the antiparkinsonian effects without a marked induction of hyperactivity. However, the combination treatment at higher doses induced marked hyperactivity accompanied by augmented antiparkinsonian effects. These results suggest that stimulation of either central dopamine D1 or D2 receptors is requisite for the antiparkinsonian effects and concurrent strong stimulation of both central dopamine D1 and D2 receptors causes marked hyperactivity which may be predictive of dopaminergic psychiatric side effects.

Differential effects of three dopamine receptor agonists in MPTP-treated monkeys

The behavioral effects of cabergoline, pergolide and bromocriptine were investigated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys with attention to the induction of hyperactivity, as evidenced by irritability, excitability and aggressiveness. All three drugs improved the parkinsonism in a dose-dependent fashion following a single injection. Among the three dopamine (DA) receptor agonists used, the antiparkinsonian effect of pergolide was the strongest and had an immediate effect, while cabergoline showed the longest duration of the antiparkinsonian effect and was least potent in inducing hyperactivity.

Muscle metabolism during exercise using phosphorus-31 nuclear magnetic resonance spectroscopy in adolescents

Very little has been reported on muscle energetics during exercise in adolescents. This is attributable to the difficulty of subjecting children to muscle biopsy. The purpose of this study was to investigate the characteristics of muscle metabolism during exercise in vivo in adolescents by comparing firstly, with adults and secondly, the differences resulting from physical activity using phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. The subjects were boys aged 12 to 15 years, comprising 21 trained boys and 23 control boys, and 6 adults controls. The ratio of phosphocreatine (PCr):(PCr + P(i)), where P(i) is inorganic phosphate intracellular pH at exhaustion and the time constant of PCr during recovery were measured in all the subjects using 31P NMR. Both groups of children showed higher values of PCr:(PCr + P(i)) and intracellular pH at exhaustion than did the adult control group (P < 0.01 or P < 0.05). However, no significant differences were found between the trained boys and the control boys with respect to PCr:(PCr + P(i)) and intracellular pH at exhaustion. On the other hand, we found the same values for PCr time constant in all groups. This result suggested no differences of the muscle oxidative capacity between children and adults. We concluded that the adolescents, aged 12 to 15 years in both the trained and control groups, had less glycolytic ability during exercise than the adults.

Measurement of muscle fibre displacement during contraction by real-time ultrasonography in humans

The contact point (P) made by both the echoes of the aponeurosis and from interspaces among fascicles of the tibialis anterior muscle was detected by real-time ultrasound scanning in 12 adults. Movement in the location of P was observed during muscle contraction and its displacement was related to changes in ankle joint angles (r = 0.81, P < 0.01), i.e., P shifted proximally when the ankle joint was dorsiflexed. There was also a significant positive correlation between the degree of dorsiflexion and the velocity related to the change in location of P (r = 0.84, P < 0.01). Ultrasound measurements of the displacement and the velocity of P were reproducible as there was no variation noticed among measurements on different days. It is suggested from these results that the displacement of P reflected changes in muscle length during contraction and that this amount of change corresponded to changes in joint angles.

In vivo human myocardial metabolism during aerobic exercise by phosphorus-31 nuclear magnetic resonance spectroscopy

A few studies have been made in vivo on human myocardial energy metabolism. Hence, no discussion has taken place on metabolism during exercise or of training effects on metabolism. We examined human myocardial energy metabolism at rest and during exercise, and also training effects on the metabolism by phosphorus-31 nuclear magnetic resonance (31P NMR)-spectroscopy. Six sedentary male students (Cont) and six male long distance runners (Tr) were the subjects. Energy metabolism data were obtained from myocardium during rest and exercise by the region selection method using 31P NMR. Rotation of the legs while riding a bicycle, which was fitted with an ergometer we had made ourselves for NMR, imposed given exercise intensities. The heart rate was measured in a stationary phase during exercise. Although the heart rate at rest in the Tr group was significantly lower [Tr, 52.5 (SD 3.1) beat.min-1; Cont, 67.1 (SD 2.9) beat.min-1], no significant difference was observed in myocardial energy metabolism using the 31P NMR method [Tr, phosphocreatine/beta-adenosine 5'-triphosphate (PCr/beta-ATP); 1.51 (SD 0.02); Cont, 1.51 (SD 0.01)]. When NMR measurements were investigated at two different intensities of exercise, heart rates in the Cont group were significantly higher by about 20 beat.min-1 than those in the Tr group at both exercise intensities, while no difference in energy metabolism was observed between the groups or between rest and exercise [Tr, 75.9 (SD 3.6), 88.3 (SD 3.7) beat.min-1; PCr/beta-ATP 1.51 (SD 0.03), 1.51 (SD 0.03); Cont, 95.9 (SD 2.4), 115.1 (SD 3.5) beat.min-1, PCr/beta-ATP 1.51 (SD 0.01), 1.51 (SD 0.04)].(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle energetics in short-term training during hypoxia in elite combination skiers

Four well-trained combination skiers were studied through pre- and post-training for the effects of short-term intermittent training during hypoxia on muscle energetics during submaximal exercise as measured by Phosphorus-31 nuclear magnetic resonance and maximal aerobic power (VO2max). The hypoxia and training in the cold was conducted in a hypobaric chamber and comprised 60-min aerobic exercise (at an intensity equivalent to the blood lactate threshold), using a cycle ergometer or a treadmill twice a day for 4, consecutive days at 5 degrees C, in conditions equivalent to an altitude of 2000 m (593 mm Hg). No change in VO2max was observed over the training period, while in the muscle energetics during submaximal exercise, the values of phosphocreatine/(phosphocreatine+inorganic phosphate) and intracellular pH were found to be significantly increased by training during hypoxia. During recovery, the time constant of phosphocreatine was found to have been significantly reduced [pre, 27.9 (SD 6.7) s; post, 22.5 (SD 4.7) s, P < 0.01]. The observed inhibition of phosphocreatine as well as that of intracellular pH changes after training during hypoxia and quicker recovery of phosphocreatine in submaximal exercise tests, may indicate improved oxidative capacity (i.e. a high adenosine 5'-triphosphate formation rate) despite the short-term hypoxia training.

Pharmacological characterization of the novel anxiolytic beta-carboline abecarnil in rodents and primates

beta-Carboline abecarnil was behaviorally and biochemically characterized as a new anxiolytic agent in rodents and primates in comparison with the benzodiazepine (BZ) anxiolytics. Oral treatment with abecarnil (0.5-10 mg/kg) showed a potent anticonflict activity in the water-lick test in rats. The minimal effective dose was lower than those of BZ anxiolytics, such as etizolam, diazepam, clotiazepam and tofisopam. Abecarnil also showed taming effects to suppress fighting and aggressive behaviors in mice and monkeys with little sedative and ataxic effects, in contrast to the BZ anxiolytics producing marked sedative and ataxic effects. Furthermore, abecarnil suppressed both the sedative and ataxic effects induced by diazepam. Abecarnil bound to rat cerebellar BZ1 receptors (Ki = 0.24 nM) with higher affinity than to rat spinal cord BZ2 receptors (Ki = 1.3 nM), whereas BZ derivatives bound to both the receptors with a low and equal affinity. GABA-ratios of abecarnil were 1.9 for the BZ1 receptors and 2.8 for the BZ2 receptors, and they were smaller than those of diazepam and flunitrazepam. Thus, in contrast to the BZ derivatives, abecarnil may act as a selective partial agonist at central BZ1 receptors, resulting in its potent anticonflict and taming effects with little sedative and ataxic effects.

Changes in magnetic resonance images in human skeletal muscle after eccentric exercise

To investigate the time-course of changes in transverse relaxation time (T2) and cross-sectional area (CSA) of the quadriceps muscle after a single session of eccentric exercise, magnetic resonance imaging was performed on six healthy male volunteers before and at 0, 7, 15, 20, 30 and 60 min and 12, 24, 36, 48, 72 and 168 h after exercise. Although there was almost no muscle soreness immediately after exercise, it started to increase 1 day after, peaking 1-2 days after the exercise (P < 0.01). Immediately after exercise, T2 increased significantly in the rectus femoris, vastus lateralis and intermedius muscles (P < 0.05) and decreased quickly continuing until 60 min after exercise. At and after the 12th h, a significant increase was perceived again in the T2 values of the vastus lateralis and intermedius muscles (P < 0.01) [maximum 9.3 (SEM 2.8)% and 10.9 (SEM 2.2)%, respectively]. The maximal values were exhibited at 24-36 h after exercise. In contrast, the rectus femoris muscle showed no delayed-stage increase. Also, in CSA, an increase after 12 h was observed in addition to the one immediately after exercise in the vastus lateralis, intermedius and medialis and quadriceps muscles as a whole (P < 0.01), reaching the maximal values at 12-24 h after exercise. The plasma creatine kinase activity remained unchanged up to 24 h after and then increased significantly 48 h after exercise (P < 0.05). Beginning 12 h after exercise, the subjects whose T2 and CSA increased less than the others displayed a faster decrease in muscle soreness.(ABSTRACT TRUNCATED AT 250 WORDS)

Dilemma in the treatment of Parkinson's disease with L-dopa

L-Dopa pioneered the symptomatic therapy of Parkinson's disease. While this treatment proved effective in the treatment of parkinsonian akinesia, rigidity and tremor, prolonged L-dopa treatment was often noted to result in dyskinesia, psychosis and 'on-off' phenomena. This increasing disability of L-Dopa-treated parkinsonian patients, however, is not correlated with the duration of L-dopa treatment. Mortality due to Parkinson's disease has decreased significantly after the introduction of L-dopa treatment. The development of D1-selective dopamine agonists and the introduction of neuroprotective rather than symptomatic therapy are required for treating Parkinson's disease.