Effect of central scotomata on pattern reversal visual evoked potentials in patients with maculopathy and healthy subjects

The effect of central scotomata on pattern reversal visual evoked potential (PVEP) was investigated in patients with maculopathy and healthy subjects. PVEP was evoked monocularly by both full-field and half-field stimulations. Since the latency of 'the major positivity at Oz' (P100-Oz) is used as the most reliable parameter in the clinical application of PVEP, special attention was focused on its changes, comparing with 'ipsilateral major positivity of half-field PVEP' (P100-IHF). Although the incidence of modification was lower in the patients, central scotomata modified PVEPs of the healthy subjects and of the affected eye of the patients in a similar manner: full-field PVEP showed prolonged latency and reduced amplitude of P100-Oz. Half-field PVEP disclosed prolonged P100-Oz latency with intact P100-IHF latency. Only difference was that amplitude reduction of both P100-Oz and P100-IHF of half-field PVEP was observed only in the healthy subjects. The prolonged P100-Oz latency of half-field PVEP was accompanied, both in the healthy subjects and in the patients, by a contralateral negative-positive complex (N105-P135) which was augmented and extended to Oz. The prolonged P100-Oz latency, thus, was due to the pronounced P135. These observations suggested that an attenuation of the afferent impulses from the central retina may cause a prolongation of the P100-Oz latency in both healthy subjects and patients, but this is not a reflection of the truly prolonged P100-IHF latency. It was concluded that, in the clinical application of PVEP, recordings of half-field PVEP from the lateral electrodes seem to be essential to distinguish true prolongation of the P100-Oz latency.     

Progesterone inhibition in mid-trimester termination of pregnancy: physiological and clinical effects

A double-blind, placebo controlled clinical trial was conducted to assess the clinical and physiological effects of 'epostane', a progesterone synthesis inhibitor, in mid-trimester prostaglandin termination of pregnancy. Mean peripheral progesterone levels had fallen by 74% after 72 h in the patients treated wtih epostane. The mean induction-abortion interval in the treatment group was 490 (SD 271) min, compared with 1432 (SD 640) min in the control group. Intrauterine pressure recording demonstrated increased sensitivity to prostaglandin E2 after epostane treatment but no change in oxytocin sensitivity. The clinical implications of facilitated induction of abortion are discussed.     

gamma-Aminobutyric acid enhances the tone of human internal anal sphincter.

The effect of gamma-aminobutyric acid (GABA) on the human internal anal sphincter was investigated. Cumulative applications of GABA produced concentration-dependent contractions (10(-8)-10(-5) M) of the isolated human sphincter. Pretreatment with bicuculline (GABAA antagonist) turned them to relaxation. Muscimol, a GABAA agonist, induced concentration-dependent contractions (10(-8)-10(-5) M); however, baclofen (GABAB agonist, 10(-8)-10(-5) M) promoted concentration-dependent relaxation of the strips. These results suggested that both excitatory GABAA receptors and inhibitory GABAB receptors exist in the internal anal sphincter. Oral administration of sodium valproate (1600 mg/day), a GABA transaminase inhibitor, enhanced the anal canal resting pressure in 10 normal volunteers. Anal manometry showed a significant elevation in tonus without affecting amplitudes or frequencies. These results indicated that endogenous GABA, which was increased by sodium valproate, produced elevations in the anal canal resting pressure through its specific receptors in the human internal anal sphincter.     

Cephalometric measurements in snorers, non-snorers, and patients with sleep apnoea.

Cephalometry is often used to assess patients with sleep apnoea but whether these measurements differ from those in non-apnoeic snorers and how they are influenced by age is not clear. Cephalometric radiographs of patients with sleep apnoea were compared with those of snorers without sleep apnoea and those of non-snorers. Fifty two snorers with suspected sleep apnoea had a conventional sleep study and were divided into two groups: those with an apnoea-hypopnoea index greater than 10/h (n = 40, sleep apnoea group) and those whose apnoea-hypopnoea index was 10/h or less (n = 12, snorer group). The cephalometric measurements in these patients were compared with those of 34 non-snoring control subjects. Controls were subdivided into two groups: control group 1 included 17 subjects similar in age to the sleep apnoea and snorer groups (mean (SD) age 50.0 (10.9), 50.7 (9.4), and 50.6 (9.7) years); control group 2 included 15 young men (25.4 (2.6) years). The distance from the mandibular plane to the hyoid bone (MP-H) and the length of the soft palate were greater in the patients with sleep apnoea (28.7 (7.8) and 43.6 (5.0) mm) than in the snorers (23.7 (4.2) and 40.3 (4.9 mm). The MP-H was similar in snorers and age matched control subjects, but was significantly greater in the older than in the younger control subjects (22.1 (6.1) vs 17.0 (6.8]. The soft palate was longer in subjects who snored (both sleep apnoea patients and snorers) than in control subjects. The MP-H distance significantly correlated with age for all subjects (snorers and controls) and for the control subjects alone. This study shows that non-apnoeic snorers have cephalometric abnormalities that differ from those of patients with sleep apnoea and that cephalometric values are influenced by the subject's age.     

Effect of meal on the physiological and physicochemical actions of potassium citrate

The effect of meals on the physiological and physicochemical actions of potassium citrate was examined in 8 patients with nephrolithiasis maintained on a constant metabolic dietary regimen. Potassium citrate (20 mEq. 3 times per day), whether given with food or on an empty stomach, significantly increased urinary pH, citrate and potassium, and decreased urinary calcium and ammonium. Moreover, potassium citrate decreased urinary saturation of calcium oxalate and uric acid, although it slightly increased that of brushite. However, there was no significant difference in these measures when the drug was given with meals from the time when it was given on an empty stomach. Thus, the effect of potassium citrate on urinary risk factors is unaffected by food.     

Localization of basic FGF-like immunoreactivity in the hypothalamo-hypophyseal neuroendocrine axis

We examined the localization of basic fibroblast growth factor (basic FGF) in the adult rat brain by immunohistochemical and Western blotting analysis using a specific antibody against a synthetic basic FGF fragment (N-terminal 12 residues). The antibody did not cross-react with acidic FGF. Basic FGF-like immunoreactivity was located exclusively in the neuronal elements and had very heterogenous distribution. Immunoreactive cell bodies were observed in the paraventricular, supraoptic and circular nuclei of the hypothalamus. Numerous immunoreactive neuronal processes originating from these basic FGF-positive cells extended lateroventrally and then caudally to the internal layer of the median eminence. In addition, the neurohypophysis contained a significant number of basic FGF-like immunoreactive fibers. Western-blotting analysis revealed that the hypothalamus and the hypophysis contained a main band of basic FGF immunoreactive with an apparent molecular weight of 17 kDa. These results show that the hypothalamo-hypophyseal neuroendocrine pathway contains basic FGF.     

Increased 5-HT-2 receptor function as measured by serotonin-stimulated phosphoinositide hydrolysis in platelets of depressed patients.

1. The present study was undertaken to examine whether or not 5-HT-induced inositol monophosphate (IP-1) accumulation in human platelets is mediated by 5-HT-2 receptors and to assess 5-HT-2 receptor function as measured by 5-HT-stimulated IP-1 accumulation in platelets from normal controls and depressed patients before drug treatment. 2. In platelets prelabeled with 3H-myo-inositol, in Ca ion free HEPES buffer containing 10 mM LiCl, 5-HT caused a dose-dependent accumulation of IP-1 during 15 min incubation. A maximal increase in IP-1 formation was observed at 30 microM of 5-HT and its EC50 value was 4 microM. 3. Ketanserin, a selective 5-HT-2 antagonist, was a potent inhibitor of 5-HT-stimulated IP-1 accumulation with a Ki value of 12 nM, but (-)propranolol (10 microM), a 5-HT-1 antagonist, failed to block the 5-HT response. 4. The potencies of various compounds tested to inhibit 5-HT-stimulated IP-1 accumulation in human platelets correlated positively with the affinities to 5-HT-2 receptor as defined by radioligand binding in rat cerebral cortex. 5. In a group of unmedicated patients with major depressive disorder matched for age with normal control group, we found a significant increase in 5-HT (100 microM)-induced accumulation of IP-1 (150 +/- 7% of basal for depressed patients, 132 +/- 3% for controls).     

The effect of methamphetamine on serotonin and its metabolite in the suprachiasmatic nucleus: A microdialysis study

Summary The suprachiasmatic nucleus (SCN) has been identified as a major circadian pacemaker. Methamphetamine has been shown to modify the behavior of circadian rhythms. We detected extracellular serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the SCN in freely moving rats, using a microdialysis method, to investigate biochemical effects of methamphetamine in the SCN. Methamphetamine infusion into the SCN dose-dependently increased extracellular 5-HT and decreased extracellular 5-HIAA.     

Thyrotropin and prolactin responses to ECT in schizophrenia and depression

Thyroid stimulating hormone (TSH) and prolactin (PRL) plasma levels were studied during electroconvulsive therapy (ECT) in five schizophrenic patients in a simulated ECT (SECT) controlled experimental design. The data were compared to those obtained from a group of 10 depressed patients treated with ECT. In the schizophrenic group, both PRL and TSH increased significantly during ECT compared to SECT, as they did in the depressive group during ECT. Thus, the hormonal TSH and PRL profile during ECT is similar in schizophrenia and depression. It is concluded that the changes in TSH and PRL induced by ECT are specifically linked to the current or the seizure, and are not related to the type of psychopathology.     

Neural control of urinary sodium excretion during hypertonic NaCl load in conscious rabbits: role of renal and hepatic nerves and baroreceptors

We examined responses of renal nerve activity, urine flow, and urinary Na+ excretion to a hypertonic NaCl infusion in chronically instrumented conscious rabbits with unilateral renal denervation. The intravenous infusion of 20% NaCl, at 0.2 ml/min for 30 min, increased plasma osmolality by 27 +/- 5 mOsm/kg, and plasma Na+ by 16 +/- 3 mEq/l, and decreased hematocrit by 5 +/- 1%. These changes were accompanied by a marked decrease in renal nerve activity by 82 + 7%. Urine flow and urinary Na+ excretion increased gradually and peaked at the end of infusion. The innervated kidney excreted 23.3 +/- 3.3 ml urine and 5.5 +/- 0.7 mEq Na+ for the subsequent 60 min. However, the contralateral denervated kidney excreted only 9.5 +/- 2.0 ml urine and 2.2 +/- 0.6 mEq Na+; these values were significantly less than those of the innervated kidney. To examine the role of the sinoaortic and cardiopulmonary baroreceptors and the hepatic nerves in the response of renal nerve activity to the hypertonic NaCl infusion, renal nerve activity was examined in conscious rabbits with sinoaortic baroreceptor denervation (SAD) plus vagotomy and/or section of the anterior and posterior hepatic nerves (SAPH). In rabbits with SAD plus vagotomy or SAPH, the NaCl infusion also decreased renal nerve activity. After combining SAPH and SAD plus vagotomy, the decrease in renal nerve activity was completely blocked. These results indicate that hypertonic NaCl infusion elicits a marked decrease in renal nerve activity which is mediated predominantly by sinoaortic and cardiopulmonary baroreflexes and the hepatic nerves, and that the decrease in renal nerve activity plays an important role in the augmentation of renal function.