Unique eye of probable evolutionary significance.

The eyes in the brain of a larval flatworm studied by electron microscopy are dissimilar. Light-sensitive structures in the right eye are microvilli; those in the left eye, the unique one, are both microvillar and ciliary. Perhaps this is evidence for the origin of a microvillar line of photoreceptoral evolution from a more primitive ciliary line.

Kinetic properties of an enzyme highly enriched in carbon-13.

Preparations of Candida utilis 6-phosphogluconate dehydrogenase with extreme variation in carbon isotope composition have been obtained. Molecular activities, pH optima and substrate affinities of these enzyme preparations have been measured. It was observed that any effect of isotope composition on these physiologically important properties is minimal.

The Impact of Colleague Peer Review on the Radiotherapy Treatment Planning Process in the Radical Treatment of Lung Cancer.

AIMS: Modern radiotherapy uses techniques to reliably identify tumour and reduce target volume margins. However, this can potentially lead to an increased risk of geographic miss. One source of error is the accuracy of target volume delineation (TVD). Colleague peer review (CPR) of all curative-intent lung cancer plans has been mandatory in our institution since May 2013. At least two clinical oncologists review plans, checking treatment paradigm, TVD, prescription dose tumour and critical organ tolerances. We report the impact of CPR in our institution. MATERIALS AND METHODS: Radiotherapy treatment plans of all patients receiving radical radiotherapy were presented at weekly CPR meetings after their target volumes were reviewed and signed off by the treating consultant. All cases and any resultant change to TVD (including organs at risk) or treatment intent were recorded in our prospective CPR database. The impact of CPR over a 13 month period from May 2013 to June 2014 is reported. RESULTS: One hundred and twenty-two patients (63% non-small cell lung carcinoma, 17% small cell lung carcinoma and 20% 'clinical diagnosis') were analysed. On average, 3.2 cases were discussed per meeting (range 1-8). CPR resulted in a change in treatment paradigm in 3% (one patient proceeded to induction chemotherapy, two patients had high-dose palliative radiotherapy). Twenty-one (17%) had a change in TVD and one (1%) patient had a change in dose prescription. In total, 6% of patients had plan adjustment after review of dose volume histogram. CONCLUSION: The introduction of CPR in our centre has resulted in a change in a component of the treatment plan for 27% of patients receiving curative-intent lung radiotherapy. We recommend CPR as a mandatory quality assurance step in the planning process of all radical lung plans.

The effect of thiamin and riboflavin supplementation on the level of those vitamins in human breast milk and urine.

Thiamin and riboflavin concentrations in urine and breast milk were measured to see if vitamin supplementation during lactation is beneficial to healthy well-nourished women. seven supplemented subjects and five nonsupplemented subjects expressed milk four times per day for 3 days at 1 and 6 weeks postpartum. Dietary intakes were recorded for 1 day before milk collection and the 3 days of milk collection. A 24-hr urine sample was collected at 1 and 6 weeks postpartum. Mean thiamin concentration in the milk increased significantly in both groups between 1 and 6 weeks postpartum, although there were no significant differences between groups. Riboflavin values reflected in the milk were significantly lower in the nonsupplemented group of women both at 1 and 6 weeks postpartum, but values did not change significantly in either groups as the milk matured from 1 to 6 weeks postpartum. Urinary excretion of thiamin and riboflavin was proportionally higher in the supplemented group of women. Riboflavin and thiamin status of both groups of women depicted normal intakes and the milk concentration of thiamin and riboflavin either met or exceeded established norms in both groups of women.

The effects of vitamin C, vitamin B6, and vitamin B12 supplementation on the breast milk and maternal status of well-nourished women.

The effects of vitamin supplements and/or diet on the levels of vitamin C, vitamin B6, and vitamin B12 in milk and blood of lactating women were determined. At the end of gestation, subjects were divided into two lactation groups: supplemented (10 subjects) and nonsupplemented (seven subjects). Milk samples were collected from 5 to 7 days and 43 to 45 days postpartum. Fasting blood samples were drawn at 8 and 46 days postpartum for vitamin C, B6, and B12 status measurements. Dietary records of all foods consumed by the subject were kept for 4 days at 1 and 6 weeks postpartum. The vitamin B6 level in breast milk of the unsupplemented group of mothers was significantly lower (P less than 0.05) than the supplemented group of women at 5 to 7 days postpartum. Vitamin B12 concentration in milk of nonsupplemented mothers at 43 to 45 days postpartum was significantly lower (P less than 0.05) than the supplemented group of women at 43 to 45 days postpartum. None of the milk values or the maternal blood levels measured in the women was less than published norms for vitamin C, vitamin B6, and vitamin B12.

Non-small cell lung cancer and CHART (continuous hyperfractionated accelerated radiotherapy)--where do we stand?

This paper reviews the use of hyperfractionated and/or accelerated radiation therapy in the curative treatment of non-small cell lung cancer, and explains the scientific rationale behind the development of these regimes. The indications, practicalities and economics of introducing them routinely are addressed. Novel radiotherapy techniques are further discussed in the context of current developments and on-going clinical trials.

Transport of pinocytic vesicles in the eye of a snail, Helix aspersa.

The heads of small adult snails, Helix aspersa, were injected with horseradish peroxidase (HRP) for one to five hours before extirpating the eyes and preparing them cytochemically for electron microscopy. There was internalization of tracer by pinocytic vesicles (pinosomes) at the bases of types-I and -II sensory cells, ganglion cells and, in lesser amounts, by pigmented supportive cells. Vesicles and vacuoles filled with HRP were transported in two directions: lensward as far distad as the ends of the cells (retrograde) and brainward down the optic nerve (anterograde). We believe that the numerous reacted vacuoles in the cell somata are formed by fusion of vesicles, tubules and C-shaped organelles filled with tracer; we present evidence that they become secondary lysosomes. Sensory cell type II possesses more HRP-reacted vacuoles distally than the other retinal cells. Other vesicles are also described. There was no uptake of tracer by the distal ends of the retinal cells following injection HRP into the hemolymph. The swelling of the optic nerve, immediately behind the eye, contains more HRP-filled pinosomes and vacuoles than does the nerve below the dilatation. The significance of endocytosis and transport of pinosomes within the eye and down the optic nerve is discussed.

Carbon-13 nuclear-magnetic-resonance spectroscopy of whole cells and of cytochrome C from Neurospora crass grown with (S-Me-13C)methionine.

Neurospora crassa cytochrome C biosynthetically labelled with [S-Me-13C]methionine was prepared and analysed by 13C nuclear-magnetic-resonance spectroscopy. The methyl group of methionine is extensively incorporated into an N-trimethyl-lysine-72 residue arise from S-adenosylmethionine transmethylation, and that the methyl carbons of methionine residues are sufficiently close to the haem centre to experience chemical shifts from the ring currents of the tetrapyrrole pi electrons and broadening due to binding of methionine-80 with the haem, as well as interaction of the S-E113C]methyl groups with the paramagnetic iron centre. Although whole cells of the labelled Neurospora produced a 13C resonance at the expected position for the methionyl methyl group most of the methyl label was diverted into N-tetra-alkyl ammonium compounds. After an active state of growth these labelled N-methyl compounds appear, in the main, to be low-molecular-weight derivatives of choline which, if associated with membrane, are in a sufficiently fluid environment to have short rotational correlation times. During a subsequent dormant growth period these compounds become associated to some extent with relatively more immobile phases as a result of membrane binding or an increase in membrane rigidity.

Studies on the biosynthesis of aspergillin by Aspergillus niger.

Two inhibitors of the biosynthesis of aspergillin, the black spore pigment of Aspergillus niger, have been investigated. 2,4-Dithiopyrimidine exerted its inhibitory effect by intracellularly chelating cupric ion required for normal pigmentation. Dimethylsulfoxide prevented the synthesis of certain phenolic precursors of the native pigment. Partial purification and characterization of pigments from mature cultures revealed the presence of at least three components: (i) a high-molecular-weight (approximately 20,000) native pigment fraction in untreated mold cultures, (ii) a lower-molecular-weight (approximately 5,000) melanin pigment found in both types of inhibited cultures, and (iii) a low-molecular-weight (368) green pigment found only in the 2,4-dithiopyrimidine-inhibited cultures and proposed to be a pentacyclic quinonoid derivative. A pathway for aspergillin biosynthesis is suggested based on these results.