Determination of glucokinase and hexokinase activity in liver extracts previously purified on Molselect G-50 dextran gel

Hexokinase and glucokinase activity in the supernatant of a rabbit liver homogenate obtained at 18,000g was determined by a spectrophotometric method. Preliminary purification to remove low-molecular-weight components by gel filtration on Molselect G-50 dextran was shown to prevent reduction of NADP unconnected with the hexokinase reaction.Presented by Academician of the Academy of Medical Sciences of the USSR V. S. Il'in.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 891–892, July, 1976.     

Developmental expression of FOG-1/CPEB protein and its control in the Caenorhabditis elegans hermaphrodite germ line.

The specification of a germ cell as sperm or oocyte and determination of cell number remain unsolved questions in developmental biology. This paper examines Caenorhabditis elegans FOG-1, a CPEB-related RNA-binding protein that controls the sperm fate. We find that abundant FOG-1 protein is observed transiently in germ cells just prior to their expression of an early sperm-differentiation marker. As the germline tissue elongates, abundant FOG-1 appears more and more distally as sperm become specified, but disappears when the germ line switches to oogenesis. This dynamic pattern is controlled by both globally acting and germline-specific sex-determining regulators. Importantly, the extent of FOG-1 expression corresponds roughly to sperm number in wild-type and mutants, altering sperm number. By contrast, three other key regulators of the sperm/oocyte decision do not similarly correspond to sperm number. We suggest that FOG-1 is precisely modulated in both time and space to specify sperm fate and control sperm number.     

Sex determination and the maternal dominance hypothesis

The maternal dominance hypothesis has been derived from workwith humans which shows that women who are more dominant thanother women are more likely to conceive sons. In both animalsand humans dominance is a characteristic or personality trait,underpinned by testosterone and responsive to a range of environmentalchanges: physical, social and psychological. Studies of thesex ratio in the social sciences and animal behaviour eithersupport or are compatible with the idea that the sex-determiningrole of X- and Y-chromosome bearing spermatozoa may be precededby factors under maternal control which provide for differentialaccess of spermatozoa. Findings in reproductive physiology andphysiological psychology suggest that folh'cular testosteroneor a related hormone may play a critical role. Reproductivephysiologists have already identified maternal mechanisms whichcould provide the context for such a model.     

Improvements to a method for determining leg length following total hip arthroplasty

Abstract

Discrepancy in leg length does frequently occur as a side effect of total hip arthroplasty and may lead to reduced patient satisfaction as well as injury in the sequalae. It is consequently important to reduce leg length discrepancy where-ever technically possible. This may be achieved by recording precise intraoperative measurements and using different sized implanted components. The aim of the given study was to improve the accuracy of a previously validated optic measurement system (OMS) to reduce leg length discrepancy. This pre-existing OMS was first trialled and based on these preliminary findings developed further. Using this improved system, measurements were taken in models and cadavers. Inter observer reliability of the improved OMS was assessed. The system is introduced in the given technical feasibility study. Its accuracy was greater in the model setup (swivel joint: 772.7?±?1.5?mm; ball joint: 770.0?±?3.7?mm; reference: 772?mm) compared to the trial using cadaveric tissues (588.8?±?5.7?mm; reference: 586?mm). Results of two examiners were similar. The third one measured significantly shorter values (p=.011). The results of the measurements with the OMS indicate that a significant increase in accuracy (p?=?2.076×¹⁰?⁶) has been achieved compared to the previously reported system, however, a further improvement to measurement accuracy is necessary for this to be applied clinically.     

Sex determination in platypus and echidna: autosomal location of <Emphasis Type="Italic">SOX3</Emphasis> confirms the absence of <Emphasis Type="Italic">SRY</Emphasis> from monotremes

In eutherian ('placental') mammals, sex is determined by the presence or absence of the Y chromosome-borne gene SRY, which triggers testis determination. Marsupials also have a Y-borne SRY gene, implying that this mechanism is ancestral to therians, the SRY gene having diverged from its X-borne homologue SOX3 at least 180 million years ago. The rare exceptions have clearly lost and replaced the SRY mechanism recently. Other vertebrate classes have a variety of sex-determining mechanisms, but none shares the therian SRY-driven XX female:XY male system. In monotreme mammals (platypus and echidna), which branched from the therian lineage 210 million years ago, no orthologue of SRY has been found. In this study we show that its partner SOX3 is autosomal in platypus and echidna, mapping among human X chromosome orthologues to platypus chromosome 6, and to the homologous chromosome 16 in echidna. The autosomal localization of SOX3 in monotreme mammals, as well as non-mammal vertebrates, implies that SRY is absent in Prototheria and evolved later in the therian lineage 210-180 million years ago. Sex determination in platypus and echidna must therefore depend on another male-determining gene(s) on the Y chromosomes, or on the different dosage of a gene(s) on the X chromosomes.     

Comparative chromosome mapping of sex-linked genes and identification of sex chromosomal rearrangements in the Japanese wrinkled frog (Rana rugosa, Ranidae) with ZW and XY sex chromosome systems

There are regional variations of sex chromosome morphologies in the Japanese wrinkled frog, Rana rugosa (2n = 26): heterogametic ZZ/ZW-type and XX/XY-type sex chromosomes, and two different types of homomorphic sex chromosomes. To search for homology between the ZW and XY sex chromosomes and the chromosome rearrangements that have occurred during sex chromosomal differentiation in R. rugosa, we performed chromosome mapping of sexual differentiation genes for R. rugosa by FISH. Three genes, AR, SF-1/Ad4BP and Sox3, were localized to both the ZW and XY chromosomes, and their locations were all different between the Z and W and between the X and Y. AR and SF-1/Ad4BP were located on the short arms of the W and X and the long arms of Z and Y, and Sox3 was mapped to the different locations on the long arms between the Z and W and between the X and Y, probably as a result of multiple rearrangements that occurred during the process of sex chromosome differentiation. However, the chromosomal locations of three genes were almost consistent between the Z and Y and between the W and X, indicating that the Z and Y chromosomes and the W and X chromosomes were respectively derived from the same origins. Dmrt1, which is located on avian sex chromosomes, was localized to autosomes in R. rugosa with both the ZW and XY sex chromosomes, suggesting that Dmrt1 might not be related to sex determination in this species.     

Monoclonal antibodies to three distinct epitopes on human IgE: their use for determination of allergen-specific IgE

Three different monoclonal antibodies (MAb) against human immunoglobulin E have been obtained which specifically bind to human myeloma and polyclonal IgE. The antibodies showed high avidities for soluble IgE (0.7 X 10(9) to 3.3 X 10(9) M-1). These MAb defined three distinct epitopes on IgE. A mixture of these antibodies in combination with an 125I-labelled anti-mouse Kappa chain MAb has been used to measure allergen-specific IgE. This determination was performed by a solid-phase radioimmunoassay using allergen extracts coated to either chemically activated paper discs or to polyvinyl chloride wells. This method is 4-10 times more sensitive than other previously reported procedures. A similar technique has also been applied to detect individual allergens in immunoblots of allergen extracts.     

Handling of biological samples in the determination of the anti-neoplastic drug mitomycin C

A study to ascertain suitable conditions for handling biological samples from patients, treated with the antibiotic mitomycin C (MMC), with the objective of improving the accuracy and reliability of the determination is described. Situations frequently occurring in medical practice are simulated to optimize procedures for reliable and reproducible sampling, sample treatment and determination of MMC. Continuation of drug partitioning in whole blood after sampling can be prevented by immediate cooling in ice before the separation of plasma from cells. The adjustment of the pH of urine samples is shown to be particularly important since a low urinary pH causes decomposition of MMC; moreover, it may decrease extraction recovery. Furthermore, long-term exposure of samples to daylight induces drug decomposition. Frozen storage of plasma and urine samples for periods greater than 3 weeks is to be avoided as this results in a considerable drop in MMC concentration. Repeated cycles of freezing and thawing are shown to have no effect upon the analytical results (6 cycles tested). The analysis of extracts of biological samples may take place up to at least 24 h after their preparation without measurable loss of analyte.     

Direct quantitation of antiseptic quaternary ammonium compounds by fast atom bombardment mass spectrometry

The medicinally important quaternary ammonium salts benzyldimethyltetradecylammonium chloride (BDTA), cetylpyridinium chloride and benzethonium chloride, all afford, under fast atom bombardment (FAB) mass spectrometric conditions, abundant and persistent [M---Cl]⁺ species usefully amenable to quantitative analysis with the aid of thioglycerol as a liquid FAB matrix. The use of BDTA as an internal standard allowed a direct, precise and accurate determination of cetylpyridinium and benzethonium chlorides, either as pure samples or in dosage forms, in the concentration range 0.05–2 mg/ml.