Ratios between number of neuroglial cells and number and volume of nerve cells in the spinal ganglia of two species of reptiles and three species of mammals

We studied the ratios between number of neuroglial (=satellite) cells and number and volume of neurons with which they are associated in the spinal ganglia of two species of reptiles (lizard and gecko) and three species of mammals (mouse, rat, and rabbit). In all five species, we found that the number of satellite cells associated with a nerve cell body increased with increasing volume of the latter. This result shows that there is a quantitative balance between neuroglia and nerve tissue in spinal ganglia. This balance seems to be maintained by a tight regulation of the number of satellite cells. We also found that the mean volume of nerve cell body corresponding to a satellite cell was lower for small neurons than for large ones. Since satellite cells metabolically support spinal ganglion neurons, the metabolic needs of small neurons are better satisfied than those of large ones. For a nerve cell body of a given size, the number of associated satellite cells did not differ between the lizard and gecko, nor between the mouse, rat, and rabbit. However, this number was significantly smaller in the reptiles than in the mammals. This result could be explained by the lower metabolic rate in the nervous system of poikilotherms than mammals, or could have a phylogenetic significance. These two interpretations are not mutually exclusive.     

Age-related changes of elements with their relationships in human cranial and spinal nerves

To elucidate compositional changes of peripheral nerves with aging, the authors investigated age-related changes of elements and their relationships in the optic, trigeminal, vagus, median, radial, ulnar, femoral, sciatic, tibial, and common peroneal nerves by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 10 men and 12 women, ranging in age from 65 to 91 yr. It was found that although accumulations of Ca and P occurred only in the trigeminal nerve at old age, it hardly occurred in the optic, vagus, median, radial, ulnar, femoral, sciatic, tibial, and common peroneal nerves at old age. The average contents of Ca and P were three and two times higher in the trigeminal nerve than in the other nine kinds of nerve, respectively. Likewise, the average content of Mg was a little higher in the trigeminal nerve compared with the other nerves. With regard to the relationships among elements, significant direct correlations were found among the contents of Ca, P, S, and Mg in most, but not all, 10 kinds of nerve. In the trigeminal nerve, a significant inverse correlation was found between the contents of S and the other elements, such as Ca, P, and Mg. Regarding the relationships between the contents of S and other elements, the nerves, except for the trigeminal nerve, differed from those found in the arteries previously reported.     

Effects of chronic caloric restriction on mitochondrial respiration in the ischemic reperfused rat heart

Dietary restriction increases life span and delays the development of age-related diseases in rodents. We have recently demonstrated that chronic dietary restriction is beneficial on recovery of heart function following ischemia. We studied whether the metabolic basis of this benefit is associated with alterations in mitochondrial respiration. Male Wistar rats were assigned to an ad libitum-fed (AL) group and a food restricted (FR) group, in which food intake was reduced to 55% of the amount consumed by the AL group. Following an 8-month period of restricted caloric intake, isolated working hearts perfused with glucose and high levels of fatty acids were subjected to global ischemia followed by reperfusion. At the end of reperfusion, total heart mitochondria was respiration was assessed in the presence of pyruvate, tricarboxylic acid intermediates, and palmitoylcarnitine. Recovery of heart function following ischemia was greater in FR hearts compared to AL hearts. Paralleling these changes in heart function was in increase in state 3 respiration with pyruvate. The respiratory control ratios in the presence of pyruvate and tricarboxylic acid intermediates were higher in FR hearts compared to AL hearts, indicating well-coupled mitochondria. Overall energy production, expressed as the ADP:O ratio and the oxidative phosphorylation rate, was also improved in FR hearts. Our results indicate that the beneficial effect of FR on recovery of heart function following ischemia is associated with changes in mitochondrial respiration.     

三叉神经对去运动神经支配面肌肌萎缩的影响

本文用组织化学、电镜以及肌球蛋白和肌动蛋白电泳分析了在单纯性面神经切断和三叉神经、面神经同时切断后面肌萎缩的病理改变--肌纤维的显微结构改变以及面肌收缩蛋白质在手术后不同时期的降解变化。实验证明,面部肌肉在不同的神经切断情况下其病理改变不同,正常的三叉神经支配可以延缓面瘫后肌肉蛋白质的降解,减少胶原纤维结缔组织的增生,较好地保护肌纤维的显微结构,延缓和减轻去运动神经支配面肌肌萎缩。本研究结果可以为临床治疗面瘫提供一定的理论指导。     

Palmitate oxidation by the mitochondria from volume-overloaded rat hearts

In this work, an attempt was made to identify the reasons of impaired long-chain fatty acid utilization that waspreviously described in volume-overloaded rat hearts. The most significant data are the following: (1) The slowing down of long-chain fatty acid oxidation in severely hypertrophied hearts cannot be related to a feedback inhibition of carnitine palmitoyltransferase I from an excessive stimulation of glucose oxidation since, because of decreased tissue levels of L-carnitine, glucose oxidation also declines in volume-overloaded hearts. (2) While, in control hearts, the estimated intracellular concentrations of free carnitine are in the range of the respective K_m of mitochondrial CPT I, a kinetic limitation of this enzyme could occur in hypertrophied hearts due to a 40% decrease in free carnitine. (3) However, the impaired palmitate oxidation persists upon the isolation of the mitochondria from these hearts even in presence of saturating concentrations of L-carnitine. In contrast, the rates of the conversion of both palmitoyl-CoA and palmitoylcarnitine into acetyl-CoA are unchanged. (4) The kinetic analyses of palmitoyl-CoA synthase and carnitine palmitoyltransferase I reactions do not reveal any differences between the two mitochondrial populations studied. On the other hand, the conversion of palmitate into palmitoylcarnitine proves to be substrate inhibited already at physiological concentrations of exogenous palmitate. The data presented in this work demonstrate that, during the development of a severe cardiac hypertrophy, a fragilization of the mitochondrial outer membrane may occur. The functional integrity of this membrane seems to be further deteriorated by increasing concentrations of free fatty acids which gives rise to an impaired functional cooperation between palmitoyl-CoA synthase and carnitine palmitoyltransferase I. In intact myocardium, the utilization of the generated in situ palmitoyl-CoA can be further slowed down by decreased intracellular concentrations of free carnitine.     

Relationship Between 2,5-Hexanedione Concentrations in Nerve,Serum, and Urine Alone or Under Co-Treatment With Different Doses of Methyl Ethyl Ketone,Acetone, and Toluene

To ascertain the relationship among 2,5-hexanedione (2,5-HD) concentrations in nerve, serum and urine, rats were injected subcutaneously with 2.6 mmol/kg 2,5-HD alone, or together with 2.6 or 13.0 mmol/kg of methyl ethyl ketone, acetone and toluene. 2,5-HD concentrations in sciatic nerve (NC), serum (SC) and urine (UC) were determined, and the linear regression between each two of NC, SC, and UC were calculated. There was good correlation between NC and SC, SC and UC in the 2,5-HD alone group, and good correlation between NC and SC in the co-treated groups. Co-treatment solvent had little effect on the relationship between SC and NC. 13.0 mmol/kg co-treated solvent tended to decrease the regression coefficients compared with 2.6 mmol/kg co-treated solvent. These results show that SC can be used in estimating NC in the 2,5-HD alone or co-treated groups, and UC can be used in estimating SC in the 2,5-HD alone group.     

The upper Quaternary sedimentary sequence at the Rieti Basin (central Italy): a record of sedimentation response to climatic changes

Lithostratigraphy, chronology and depositional environments of sixteen Holocene alluvial fill sediment cores from the southern part of the Conca of Rieti (central Italy) was established by sedimentological, palaeontological and ¹⁴C analyses. The study area experienced a lacustrine (or palustrine) conditions and the water level was effectively controlled by a natural damming of the valley due to intermitted travertine deposition at Le Marmore site. Apart from cores S10, S13, S14 and S8 which, at their bottom, cored sediments referable to ?Upper Pliocene and Middle Pleistocene which are not the object of this paper, as a rule the drilled sediments can be referred, bottom to top, to the following four episodes: interval a, corresponding to freshwater lacustrine/palustrine environment affected by alluvial fan progradations from the edges of the valley and active by ?Middle/?Late Pleistocene to early Holocene; in this interval, several hiatuses are supposed but are not evidenced by the bad state of preservation of the sediment cores; interval b, from 361 to 371–376 m a.s.l., recording a decrease of the water level, bracketed between the ¹⁴C ages of 6000 and 2700 yr B.P., which produced the formation of distinct shallow ponds/bogs, rich in aquatic vegetation; interval c, from 381 to 384 m a.s.l., indicating a further rise of the water level, recorded by sediments containing abundant molluscs and ostracods; interval d, the upper part of the cores, records an almost continuous drying up the area as shown by abundant hydrophilic land molluscs; and interval e, the top of all sediment cores, representing the present-day soil. It has been found that the water level fluctuations occurring in the ancient Conca are chronologically consistent with the postglacial climate pattern. It is further noticed that the episodes of water highstand correspond to the Boreal–Atlantic and Subatlantic climatic ameliorations, respectively, and that the water level dropped during the global cooling episodes recurred from ca. 6000 to 2100 yr B.P. The resulting palaeoenvironmental history agrees with that previously reported for the northern reach of the Conca of Rieti, thus suggesting a common setting for the whole area.     

Effects of Obesity and Weight Loss on Cardiac Function and Valvular Performance

KARASON, KRISTJAN, INGEMAR WALLENTIN, BO LARSSON, LARS SJOSTROM. Effects of obesity and weight loss on cardiac function and valvular performance. Obes Res. 1998;6:422–429. Objective : To study the consequences of long-standing obesity on myocardial function and valvular performance and to determine the effects of weight loss on these cardiovascular features. Research Methods and Procedures : We included 41 patients with obesity referred for weight-reducing gastroplasty, 31 patients with obesity who received dietary recommendations, and 43 lean subjects. Body weight and blood pressure were measured, and cardiac function and valvular performance were estimated echocardiographically. Left ventricular ejection fraction was used to assess systolic heart function, and the ratio of transmitral early to atrial (E/A) peak flow velocity was used as an estimate of diastolic filling. All three study groups were investigated at baseline, and the two groups with obesity were re-examined at 1-year follow-up. Results : Patients with obesity had higher blood pressure, greater cardiac output, lower ejection fraction, and reduced E/A ratio, compared with lean subjects (p<0.01). Surgical treatment of obesity led to significant decreases in body weight, whereas body weight remained unchanged in the group treated with dietary recommendations (p<0.001). In the weight loss group, blood pressure and cardiac output decreased and the E/A ratio increased (p<0.001). Left ventricular ejection fraction tended to increase in the weight loss group and decrease in the obese control group p<0.01). No significant valvular disease was observed in any of the subjects with obesity at baseline or after weight loss. Discussion : We conclude that weight reduction in subjects with obesity is associated with improvements in left ventricular diastolic filling and has favorable effects on left ventricular ejection fraction. Neither obesity nor weight loss seem to promote valvular heart disease.     

Nervous control of egg progression into the common oviduct and genital chamber of the stick-insect Carausius morosus

In Carausius morosus, egg-laying activity is nocturnal. When an oöcyte leaves the ovariole (ovulation) during the day, it remains in a chamber which is located between the genital valves until the evening. The admission of another egg into the common oviduct is possible only when the egg chamber is empty. Nerve cord transection between the 7th and 8th abdominal ganglia interrupts the reflex which controls the progression of the egg through the common oviduct.Sensory hairs on the walls of the egg chamber, which is innervated by the 8th abdominal ganglion, are described. The information perceived by these sensory hairs enters the 8th ganglion, then travels to the 7th which innervates the oviducts. Present experimental results together with the observed existence of numerous anastomoses between the segmental nerves from different ganglia, suggest that though the normal reflex travels via the nerve cord, a lateral pathway is also possible.The effector is the common oviduct. The muscular sheath of this organ shows a special feature which is related to the control of egg passage: the muscle fibres no longer form a complete layer as they do in the lateral oviducts but rather form a half-sleeve of circular fibres around the dorsal face. The contraction of this half-cylindrical muscle prevents the progression of eggs.     

DISTRIBUTION AND INNERVATION OF FACIAL BRISTLES AND HAIRS IN THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS)

The distribution and anatomy of sirenian perioral bristles (modified vibrissae) and facial hairs are of interest because of their use during feeding and tactile exploration. In the present study we have identified six fields of perioral bristles on the face of the Florida manatee (T. manatus latirostris), four (U1-U4) on each side of the upper lips and oral cavity, and two (L1-L2) on each side of the lower lip pad, inside the oral cavity and rostral to the horny mandibular pad. Each field has a characteristic location, number of bristles, and range of bristle length and diameter. There is a mean of 110 (± 19) bristles per side, with no left-right differences. Branches of the infraorbital nerve innervate the bases of the largest bristles (U2 group) on the upper bristle pad, and the inferior alveolar nerve supplies the bristles of the lower bristle pad. The dorsal and ventral buccal branches of the facial nerve innervate the superficial facial musculature, which is likely to be involved in bristle eversion and other movements which constitute feeding behavior. Hair is denser in the facial region than on the remainder of the body. Within the face, hair is denser on the oral disk than on the supradisk. The oral disk contains bristle-like hair, whereas the supradisk region possesses hair that is similar in length and diameter to that on the postcranial body. The mean total of bristles and hairs per face was 1,942. Means for the subregions were 220 (± 39) bristles on the perioral bristle pads, 601 (± 115) bristlelike hairs in the oral disk region, 710 (± 229) typical hairs in the supradisk region, and 411 (± 108) typical hairs on the chin. There were no significant differences between left and right side counts. Facial hair density was inversely correlated with facial area and body size. These data provide new information on the anatomical basis of the exceptional orofacial activities characteristic of manatees during feeding and tactile exploration.