Neurochemical correlates of sparing from motor deficits in rats depleted of striatal dopamine as weanlings

The behavioral and neurochemical effects of striatal DA depletions were investigated in rats lesioned as weanlings (Day 27) or as adults (250-300 g). Administration of 6-OHDA into the medial forebrain bundle resulted in comparably large (> or = 95%) depletions of tissue levels of DA in both age groups. As expected, rats depleted of DA as adults exhibited marked deficits in motoric behavior and body weight regulation that persisted for the 8 days of postsurgical observation. In contrast, rats depleted of DA as weanlings were spared from such deficits, and their behavior closely resembled that of age-matched controls. Microdialysis studies revealed dialysate levels of striatal DA that paralleled these age-dependent behavioral differences. At a time when age-related behavioral differences were still quite pronounced (5-6 days postsurgery), basal DA levels were reduced by 80% of control values in rats lesioned as adults whereas basal DA levels in rats lesioned as weanlings were unchanged relative to their controls. Finally, adults depleted of striatal DA as weanlings were no more sensitive to the movement-impairing effects of intrastriatal sulpiride (3.0 or 10.0 micrograms/hemisphere) infusions than were control rats. These data suggest that weanlings compensate for large, but incomplete, denervation of striatal DA with markedly enhanced release and turnover from residual terminals. This developmental plasticity may prevent the occurrence of behavioral deficits soon after the lesion and also the supersensitivity to the challenging effects of DA antagonists as animals grow into adulthood.     

Guidelines for the appropriate use of genetic tests in infertile couples

Research on genetic causes of male and female infertility rapidly expanded in the last years, following the development of in vitro fertilising techniques. Genetic tests are now available to explore the cause of the infertility and assess the risk of a given couple to transmit its genetic characteristics. This allows at-risk couples to take an informed decision when electing for a medically assisted reproduction. It also allows the professionals to offer a prenatal diagnosis when appropriate. Thus, the genetic work-up of the infertile couple has become good practice for an appropriate diagnosis, treatment and prognostic assessment. The lack of national or international rules for the genetic approach to the infertile couple, prompted the Italian community of professionals in the field of reproductive medicine to join and set up guidelines for the genetic diagnosis of male and female infertility. The group of clinical and research experts is representative of 12 national scientific societies and was supported by external experts from four international societies. We examine the clinically relevant genetic causes of male and female infertility and suggest the category of patients for which each genetic test is recommended or optional, both for an accurate diagnosis and prior to ART.     

Autosome and Sex Chromosome Diversity Among the African Pygmy Mice, Subgenus Nannomys (Murinae; Mus)

The African pygmy mice, subgenus Nannomys, constitute the most speciose lineage of the genus Mus with 19 recognized species. Although morphologically very similar, they exhibit considerable chromosomal diversity which is here confirmed and extended by the G-banding analysis of 65 mice from West and South Africa. On the basis of their karyotype and distribution area, the specimens were assigned to at least five species. Extensive differentiation both within and between species was observed that involved almost exclusively Robertsonian translocations, 23 of which are newly described. Two of the rearrangements were sex chromosome-autosome translocations, associated in some cases with partial deletions of the X or Y chromosomes. Several authors have predicted that the highly deleterious effect of this rearrangement would be reduced if the sex and autosomal segments were insulated by a block of centromeric heterochromatin. The C-banding analyses performed showed that among the species carrying X-autosome translocations, one followed the expected pattern, while the other did not. In this case, functional isolation of the sex and autosome compartments must involve other repetitive sequences or genomic traits that require further molecular characterization. Such studies will provide insight into the causes and consequences of the high diversity of sex chromosome rearrangements in this subgenus.     

Effects of nitric oxide synthase inhibition by l-NAME on oxygen uptake kinetics in isolated canine muscle in situ

We hypothesized that an acute bout of strenuous, non-damaging exercise would increase rates of protein synthesis of collagen in tendon and skeletal muscle but these would be less than those of muscle myofibrillar and sarcoplasmic proteins. Two groups ( n = 8 and 6) of healthy young men were studied over 72 h after 1 h of one-legged kicking exercise at 67% of maximum workload ( W _max). To label tissue proteins in muscle and tendon primed, constant infusions of [1-¹³C]leucine or [1-¹³C]valine and flooding doses of [¹⁵N] or [¹³C]proline were given intravenously, with estimation of labelling in target proteins by gas chromatography–mass spectrometry. Patellar tendon and quadriceps biopsies were taken in exercised and rested legs at 6, 24, 42 or 48 and 72 h after exercise. The fractional synthetic rates of all proteins were elevated at 6 h and rose rapidly to peak at 24 h post exercise (tendon collagen (0.077% h⁻¹), muscle collagen (0.054% h⁻¹), myofibrillar protein (0.121% h⁻¹), and sarcoplasmic protein (0.134% h⁻¹)). The rates decreased toward basal values by 72 h although rates of tendon collagen and myofibrillar protein synthesis remained elevated. There was no tissue damage of muscle visible on histological evaluation. Neither tissue microdialysate nor serum concentrations of IGF-I and IGF binding proteins (IGFBP-3 and IGFBP-4) or procollagen type I N-terminal propeptide changed from resting values. Thus, there is a rapid increase in collagen synthesis after strenuous exercise in human tendon and muscle. The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation.     

Atomic absorption spectrophotometry (AAS) for the evaluation of metallosis in prostheses and artificial organs: a new approach.

To study the presence of metals in body fluids and tissues after implantation of metallic biomaterials and possible related diseases, a new approach in Atomic Absorption Spectrophotometry (AAS) was developed. This technique was compared to three traditional methods: mineralisation with acid digestion (method A) also known as "wet method", dry ashing (with or without oxygen) (method B); classic Kjeldaal (method C). The new approach (method D) modifies the mineralisation phase and the instrument operating instructions. Al, Na, Cr, K, Ni, Co, Ti, Fe, Hg, Pb, V, Sb and Cu levels were tested with the four methods on bone, muscle, cartilage, skin, brain, lymph nodes, blood, urine, and hair. Test results were checked by the addition method. Results demonstrated a significantly higher percentage of Al, Cr, Ni, Ti and Hg recovery with the new approach. The advantages of method D are no residue, no redox reaction, insignificant loss of analytes and enhanced sensitivity (at ppb level vs ppm of the other methods). This approach should be considered especially when testing heavy metals and complex matrices. Its disadvantages are that it is more time consuming and requires the presence of an operator.     

Synthesis and physical properties of telechelic monodispersed diols 4. Monoaddition of 10-undecenol to novel dithiols

The synthesis of novel telechelic monodispersed diols produced from the radical monoaddition of an excess of 10-undecenol with novel α, ω-dithiols, initiated by peroxides, is presented. The telechelic dithiols employed were prepared from nonconjugated dienes and a commercially available dithiol, or by esterification of adipic acid with 2-mercaptoethanol. From these dithiols, the diols were selectively obtained in high yields. Such α, ω-dihydroxylated compounds were characterized by both ¹H and ¹³C NMR spectroscopy. The diol which exhibits the ester functions shows excellent solubility in common organic solvents contrarily to the other ones. The physical properties (T_g, T_m and decomposition temperatures) of these diols were compared and it is noted that the thermostability of these monodispersed telechelic diols is much better than those of the polydispersed commercially available ones such as poly(ethylene glycol)s or poly(tetramethylene glycol)s.