An evaluation of the ability of the peripheral vasodilator buflomedil to improve vascular patency after acute frostbite

The extent of microvascular damage from frostbite can be accurately demonstrated by vascular microcorrosion casting techniques (P. S. Daum, W. D. Bowers, Jr., J. Tejada, and M. P. Hamlet, Cryobiology 24, 65-73, 1987). In the present investigation, the peripheral vasodilator buflomedil was evaluated for its ability to ameliorate microcirculatory damage from acute experimentally induced freeze injury. This drug has been reported to decrease tissue loss in human frostbite patients when given intravenously during thawing (J. Foray, P. E. Baisse, J. P. Mont, and Cl. Cahen, Sem. Hop. Paris 56, 490-497, 1980). In seven groups of anesthetized rats, left hindpaws were cooled to heat of fusion; cooling continued until the temperature in the footpads fell to -15 degrees C. Prior to cooling, group 1 received a tail vein injection of 1 ml saline/kg, while group 2 received 10 mg buflomedil/kg. Immediately following cooling, group 3 received an injection of 10 mg buflomedil/kg. Hindpaws were rapidly rewarmed in a 40 degree C bath. During rewarming, left hindpaws from group 4 were immersed in deionized water, from group 5 in 24 mg buflomedil in deionized water, from group 6 in 30% dimethyl sulfoxide (Me2SO), and from group 7 in 24 mg buflomedil in 30% Me2SO. Right hindpaws served as controls. Vascular microcorrosion casts were made from left and right hindpaws of all groups. There was no significant difference in mean cast weights when frozen hindpaws of the seven groups were compared, although treatment with buflomedil increased the mean cast weight of control hindpaws from groups 3 and 7. It therefore appears that, in this acute model for frostbite, buflomedil does not improve vascular patency.     

A Multicenter Study on Genotype-Phenotype Correlations in the Fragile X Syndrome, Using Direct Diagnosis with Probe StB12.3: The First 2,253 Cases

We report the results of a 14-center collaborative study of genotype-phenotype correlations in 318 fragile X families; these families comprised 2,253 individuals, 1,344 of whom carried a fragile X mutation and 693 of whom had a typical full fragile X mutation. This study demonstrates that direct DNA diagnosis establishes the genotype at the FRAXA-FMR-1 locus. There was a significantly higher prevalence of “mosaic” cases among males who carry a full mutation (12%) than among females who carry a full mutation (6%); the mosaic males had a larger expansion than did the mosaic females. Mental status of premutated individuals did not differ from that of those with a normal genotype. Both the abnormal methylation of the FMR-1–EagI site and the size of the expansion were highly correlated with cytogenetics, facial dysmorphism, macroorchidism, and mental retardation (MR). Among female carriers of a full mutation, those with MR had significantly larger expansion than did those without MR. Among 164 independent couples, 3 unrelated husbands carried a premutation that suggests that the prevalence of fragile X premutations in the general population is ~0.9% of the X chromosomes. Our data validate the use of direct DNA testing for fragile X diagnosis as well as for carrier identification and support and complete the established relationships among the DNA results and the cytogenetic, physical, and psychological aspects of the disease.     

Experimental and theoretical characterization of the high-affinity cation-binding site of the purple membrane.

Binding of Mn2+ or Mg2+ to the high-affinity site of the purple membrane from Halobacterium salinarium has been studied by superconducting quantum interference device magnetometry or by ab initio quantum mechanical calculations, respectively. The binding of Mn2+ cation, in a low-spin state, to the high-affinity site occurs through a major octahedral local symmetry character with a minor rhombic distortion and a coordination number of six. A molecular model of this binding site in the Schiff base vicinity is proposed. In this model, a Mg2+ cation interacts with one oxygen atom of the side chain of Asp85, with both oxygen atoms of Asp212 and with three water molecules. One of these water molecules is hydrogen bonded to both the nitrogen of the protonated Schiff base and the Asp85 oxygen. It could serve as a shuttle for the Schiff base proton to move to Asp85 in the L-M transition.     

Positive and negative effects of mesograzers on early‐colonizing species in an intertidal rocky‐shore community

The ecological consequences of human‐driven overexploitation and loss of keystone consumers are still unclear. In intertidal rocky shores over the world, the decrease of keystone macrograzers has resulted in an increase in the dominance of herbivores with smaller body (i.e., “mesograzers”), which could potentially alter community assembly and structure. Here, we experimentally tested whether mesograzers affect the structure of rocky intertidal communities during the period of early colonization after the occurrence of a disturbance. A manipulative field experiment was conducted to exclude mesograzers (i.e., juvenile chitons, small snails, amphipods, and juvenile limpets) from experimental areas in an ecosystem characterized by the overexploitation of keystone macrograzers and predators. The results of multivariate analyses suggest that mesograzers had significant effects on intertidal community structure through negative and positive effects on species abundances. Mesograzers had negative effects on filamentous algae, but positive effects on opportunistic foliose algae and barnacles. Probably, mesograzers indirectly favored the colonization of barnacles and foliose algae by removing preemptive competitors, as previously shown for other meso‐ and macrograzer species. These results strongly support the idea that small herbivores exert a firm controlling effect on the assembly process of natural communities. Therefore, changes in functional roles of top‐down controllers might have significant implications for the structure of intertidal communities.     

Difficulties learning about the cell. Expectations vs. reality

The cell is a key concept, and accurate knowledge of it is essential for understanding many phenomena and biological processes, as well as the overall functioning of living beings. However, learning about this concept is not simple. Regarding this concept, we examined the views concerning problems that could be encountered by Master’s students training to become future teachers of natural science, compared to the difficulties suffered by a group of students in their last two years of high school. The results show the students’ learning about the cell appeared to be negatively influenced by the methodology used in classroom, being this type of difficulties the most reported by the high-school students, followed by difficulties with matters associated with the functional role of the cell. However, the methodology limitations have been the least considered by future teachers. By contrast, they consider the structural aspects of the cell as more likely to be problematic for students, followed by the functional ones. Problems concerning sizes and scales arose similarly in both cases, implying a widespread problem.     

Circadian and seasonal changes of synaptic bodies in different parts of the rabbit pineal gland.

In the mammalian pineal gland, synaptic bodies (SBs) are poorly understood organelles. Previous studies in rabbits have shown that the organelles are rather heterogeneous in shape, are few in number during the day and increase in number at night. No studies are currently available on seasonal changes in this species and it is unknown whether the biological rhythms are identical in the proximal, intermediate and distal parts of the elongated pineal. To this end, a study was made of 84 rabbits kept under natural lighting conditions to examine numerical variations of the different types of SBs in the proximal, intermediate and distal regions of pineal glands procured at different timepoints of a 24-hour cycle and in each of the four annual seasons. In the present study, rod-like, sphere-like, ovoid, rectangular and triangular SB profiles were distinguished; the first two types being the most abundant. In addition to the well-known circadian changes, with low numbers of SB profiles during the day and high numbers at night, we found pronounced season-related differences as well as differences related to pineal regions. In autumn and winter, nighttime SR profile numbers were significantly higher than in spring and summer. With respect to regional differences it was found that the amplitude of the circadian rhythm increased in a proximo-distal direction in the gland. In autumn the strongly enhanced nocturnal increase was restricted to the distal region of the gland, whereas in winter it was seen in both the distal and the intermediate regions. The regional differences are probably related to the fact that the postganglionic sympathetic fibres, which regulate pineal function, enter the gland distally and proceed rostrally to the proximal region. Taken together, the results show that day- and nightlength are structurally coded in the pineal gland by means of SB numbers. Provided the SBs of the mammalian pineal gland are involved in synaptic processes, the results suggest that synaptic processes are enhanced at night as well as in autumn and winter.     

Systematic review of pharmacological treatments in fragile X syndrome

Background  

Fragile X syndrome (FXS) is considered the most common cause of inherited mental retardation. Affected people have mental impairment that can include Attention Deficit and/or Hyperactivity Disorder (ADHD), autism disorder, and speech and behavioural disorders. Several pharmacological interventions have been proposed to treat those impairments.     

D-Galactose Causes Motor Coordination Impairment,and Histological and Biochemical Changes in the Cerebellum of Rats

Classical galactosemia is an inborn error of carbohydrate metabolism in which patients accumulate high concentration of galactose in the brain. The most common treatment is a galactose-restricted diet. However, even treated patients develop several complications. One of the most common symptoms is motor coordination impairment, including affected gait, balance, and speech, as well as tremor and ataxia. In the present study, we investigated the effects of intracerebroventricular galactose administration on motor coordination, as well as on histological and biochemical parameters in cerebellum of adult rats. Wistar rats received 5 μL of galactose (4 mM) or saline by intracerebroventricular injection. The animals performed the beam walking test at 1 and 24 h after galactose administration. Histological and biochemical parameters were performed 24 h after the injections. The results showed motor coordination impairment at 24 h after galactose injection. Galactose also decreased the number of cells in the molecular and granular layers of the cerebellum. The immunohistochemistry results suggest that the cell types lost by galactose are neurons and astrocytes in the spinocerebellum and neurons in the cerebrocerebellum. Galactose increased active caspase-3 immunocontent and acetylcholinesterase activity, decreased acetylcholinesterase immunocontent, glutathione, and BDNF levels, as well as caused protein and DNA damage. Our results suggest that galactose induces histological and biochemical changes in cerebellum, which can be associated with motor coordination impairment.