A rapid cytofluorometric method for quantitative DNA determination on fixed smears

Summary A study has been made of the possibility of using propidium iodide (PI) for the cytofluorometric determination of DNA in fixed smears. A preliminary spectrofluorometric study made it possible to define the optimal conditions for the excitation wavelength and the intensity of the emitted fluorescence. The stoichiometry and specificity of the DNA-PI bond were studied in different materials and for different fixation procedures. In order to check whether RNA might interfere, it was extracted enzymatically from test preparations selectively. The data from such treated sections were not significantly different from those obtained by means of the fluorescent Feulgen reaction (Pararosaniline-SO₂) on the same material. On the other hand, some of the advantages of the PI method are important: (a) the time required for making ready and staining the preparations is very short, and in any case is considerably shorter than the feulgen method; (b) the high quantum yield of the DNA-PI complex induces very high fluorescence intensities which can, therefore, be easily measured, even with low sensitivity instruments; (c) the spectral conditions are particularly favourable for excluding the inner filter effect from the measurement; (d) the photo-decomposition is considerably lower compared to that found in preparations stained by the conventional Feulgen method. The wise possibility of excitation (from the u.v to the green), together with the limited extent of the emission band (which is mainly in the red) are also conditions that are particularly favourable for obtaining multi-parametric determinations simultaneously from the same cell.     

Control of the circadian rhythm of the body temperature in the rat

The circadian rhythm of the rat body temperature is abolished in rats kept either in constant dark or light or blinded. The suppressive effects act most likely via the retinas. The rhythm can be inverted by reversal of the lighting regimen and it is unaffected by pinealectomy. Most likely the circadian rhythm is not related to changes in patterns of motor activity.     

Nonrandom loss of maternal chromosome 11 alleles in Wilms tumors.

A series of gene probes for chromosome 11 has been used to study the genetic events associated with the development of Wilms tumor. Examination of DNA samples from five patients with Wilms tumor in whom the tumors showed loss of chromosome 11 alleles and their parents indicate that alleles lost in the tumors are of maternal origin. These data suggest that the parental derivation of chromosome 11 alleles lost in these Wilms tumors is not random.     

Refractory cytopenias: clinical course according to bone marrow cytology and cellularity

One hundred and one patients with refractory cytopenia were reviewed for morphological classification (using bone marrow, BM, imprints for cytology and Jamshidi biopsies for BM cellularity) and clinical course. Final diagnoses were: moderate aplastic anemia (MAA), myelodysplastic syndromes (MDS) and hypoplastic acute leukemia (HAL). Ninety-two patients received high dose testosterone enanthate (TE) as first treatment (starting dose = 7-10 mg/week i.m. for at least three months). Median survival was significantly longer in MAA than in MDS and in HAL. Among MDS patients, those with primary acquired sideroblastic (AISA) and refractory (RA) anemia had median survival similar to those with MAA, but distinctly longer (p = 0.01) than patients with RA with an excess of blasts (RAEB), RAEB in transformation (RAEBtr) and chronic myelomonocytic leukemia (CMMoL). Acute leukemia (AL) developed more rarely (p less than 0.02) in MAA, AISA and RA than in RAEB, RAEBtr and CMMoL. Response to TE was seen in about two thirds of MAA and in a half of MDS and HAL patients. Among MDS patients, those with hypocellular BM developed leukemia less frequently, responded to androgens more often and survived longer than those with normocellular and, especially, with hypercellular BM. These data indicate that the cytohistological classification of refractory cytopenias identifies essentially two groups with different clinical behaviour, one (MAA, AISA and RA) having long life expectancy and a low probability of developing AL and the other (RAEB, RAEBtr, CMMoL) with a short survival and relatively frequent leukemic complication. Bone marrow hypocellularity seems to be a favourable prognostic factor in MDS. Patients with refractory cytopenias, especially those with a hypocellular BM, can be advantageously treated with androgens.     

Low diversity in the major histocompatibility complex class II DRB1 gene of the Spanish ibex, Capra pyrenaica

During the last two centuries, the Spanish ibex (Capra pyrenaica) has shown a significant demographic decline as a result of the progressive destruction of its natural habitat, disease epidemics, and uncontrolled hunting. Partial sequencing of the class II MHC DRB1 gene revealed that the Spanish ibex has remarkably low levels of genetic variation at this locus, with only six different DRB1 alleles and an observed heterozygosity of 0.429-0.579. The rates of nonsynonymous vs synonymous substitutions were significantly different in the peptide-binding region (dN/dS=5.347, P=0.002), a feature that indicates that the DRB1 gene is under positive selection. A phylogenetic analysis of the Spanish ibex and a set of domestic goat DRB1 alleles revealed that the reported sequences represent four major allelic lineages. The limited allelic repertoire of the DRB1 gene in the Spanish ibex is likely the direct result of the recent history of population bottlenecks and marked demographic decline of this species. A genetic survey of 13 microsatellite loci was consistent with this idea. The Spanish ibex subspecies C. p. hispanica and C. p. victoriae consistently showed considerably lower levels of microsatellite heterozygosity (Ho=0.184-0.231) and allelic diversity (mean number of alleles per locus=2-2.4) than those reported in other wild ruminants. This study demonstrates the significance of both natural selection and the demographic history of populations in determining patterns of genetic variation at MHC loci. In addition, our results emphasize the importance of locally adapted populations for the preservation of genetic diversity.     

A single nucleotide polymorphism alters the activity of the renal Na+:Cl- cotransporter and reveals a role for transmembrane segment 4 in chloride and thiazide affinity

The thiazide-sensitive Na+:Cl- cotransporter is the major salt transport pathway in the distal convoluted tubule of the kidney, and a role of this cotransporter in blood pressure homeostasis has been defined by physiological studies on pressure natriuresis and by its involvement in monogenic diseases that feature arterial hypotension or hypertension. Data base analysis revealed that 135 single nucleotide polymorphisms along the human SLC12A3 gene that encodes the Na+:Cl- cotransporter have been reported. Eight are located within the coding region, and one results in a single amino acid change; the residue glycine at the position 264 is changed to alanine (G264A). This residue is located within the fourth transmembrane domain of the predicted structure. Because Gly-264 is a highly conserved residue, we studied the functional properties of this polymorphism by using in vitro mutagenesis and the heterologous expression system in Xenopus laevis oocytes. G264A resulted in a significant and reproducible reduction ( approximately 50%) in (22)Na+ uptake when compared with the wild type cotransporter. The affinity for extracellular Cl- and for thiazide diuretics was increased in G264A. Western blot analysis showed similar immunoreactive bands between the wild type and the G264A cotransporters, and confocal images of oocytes injected with enhanced green fluorescent protein-tagged wild type and G264A cotransporter showed no differences in the protein surface expression level. These observations suggest that the G264A polymorphism is associated with reduction in the substrate translocation rate of the cotransporter, due to a decrease in the intrinsic activity. Our study also reveals a role of the transmembrane segment 4 in defining the affinity for extracellular Cl- and thiazide diuretics.     

An early Bathonian Tethyan ammonite fauna from Argentina

Evidence for the Lower Bathonian Substage in most of the Pacific area has been lacking or controversial because index ammonoids of the Tethyan Subrealm in southern Europe and North Africa were unknown. During the Bathonian, the East Pacific margin belonged to either the Boreal Realm or the East-Pacific Subrealm of the Tethyan Realm, each with faunas distinctly different from the Eurafrican Tethyan faunas that form the basis for the chronostratigraphical standard. The first representatives of Morphoceras from South America, M. gulisanoi sp. nov., here described from a single locality in southern Mendoza Province, clearly document the Lower Bathonian Substage, probably the Zigzag Zone. Associated ammonoids are the perisphinctoidean Procerites cf. schloenbachi de Grossouvre and the oppeliid Oxycerites ( O. ) cf. aspidoides (Oppel), also typical Tethyan elements but less useful for dating.     

Long term metabolic effects of two dietary methods of treating hyperlipidaemia.

OBJECTIVES--To compare the long term metabolic effects of two diets for treating hyperlipidaemia. DESIGN--Randomised controlled study: after three weeks of normal (control) diet, subjects were randomly allocated to one of two test diets and followed up for six months. SETTING--Lipid clinic of tertiary referral centre in Naples. SUBJECTS--63 subjects with primary type IIa and IIb hyperlipoproteinaemia entered the study, and 44 completed it. Exclusion criteria were taking drugs known to influence lipid metabolism, evidence of cardiovascular disease, homozygous familial hypercholesterolaemia, and body mass index over 30. INTERVENTIONS--Two test diets with reduced saturated fat (8%) and cholesterol (approximately 200 mg/day): one was also low in total fat and rich in carbohydrate and fibre, and the other was low in carbohydrate and fibre and rich in polyunsaturated and monounsaturated fats. MAIN OUTCOME MEASURES--Fasting plasma lipid and lipoprotein concentrations; blood glucose, insulin, and triglyceride concentrations before and after a test meal. RESULTS--In comparison with the control diet, both test diets induced significant and similar decreases in low density lipoprotein cholesterol concentrations (by a mean of 0.72 (SE 0.15) mmol/l, P < 0.001, for low total fat diet; by 0.49 (0.18) mmol/l, P < 0.05, for high unsaturated fat diet) and plasma triglyceride concentrations (by 0.21 (0.09) mmol/l, P < 0.05, for low total fat diet; by 0.39 (0.15) mmol/l, P < 0.05, for high unsaturated fat diet), while high density lipoprotein cholesterol concentrations after fasting and plasma glucose and insulin concentrations during test meals were not modified by either diet. CONCLUSIONS--Both test diets are suitable (alone or in combination) for treatment of hypercholesterolaemia.