Surgical closure of patent ductus arteriosus reduces the cerebral tissue oxygenation index in preterm infants: a near-infrared spectroscopy and Doppler study

BACKGROUND: The aim of this study was to investigate the effects of patent ductus arteriosus (PDA) ligature on cerebral oxygen saturation, cerebral blood volume (CBV) and cerebral blood flow velocity by means of near-infrared spectroscopy (NIRS) and transcranial Doppler simultaneous examinations. METHODS: This is an observational study considering 16 babies of gestational age 24-34 weeks diagnosed with PDA who underwent surgical ligation. The cerebral oxygen saturation, CBV and blood gases values were obtained 35 min before ligation, so also around the 14th and 27th min after the clip's insertion. RESULTS: Cerebral oxygen saturation, measured as tissue oxygenation index (TOI), decreased significantly after PDA ligation from a basal value of 61.1 (3.8) before surgery to 56.6 (3.3) and 55.8 (2.6)%, for the 14th and 27th min, respectively (P<0.04). CBV before and after clipping was unvaried. A negative correlation was found between DeltapH and DeltaCBV after ligation (R=0.52, P=0.03), whilst a positive correlation was found between DeltaCBV and DeltaP(aCO2) (R=0.62, P=0.009). pH increased at the 27th min post-ligation. CONCLUSIONS: NIRS is a tool for obtaining information on cerebral oxygen saturation and CBV changes during surgical PDA ligation at the bedside. A fall in TOI suggests an increased oxygen extraction during PDA surgery. The lack of increase in DeltaCBV or in diastolic flow velocity show that the PDA before the clipping did not limit cerebral blood flow, the drop in TOI suggests increased oxygen consumption over the clip and the need for accurate monitoring of oxygen utilization after the surgical treatment.     

FAMILY COMPLIANCE TO A TREATMENT PROGRAMME FOR ALCOHOLICS: A PROSPECTIVE STUDY OF PROGNOSTIC FACTORS

A total of 198 alcoholic subjects was recruited into a treatmentprogramme according to Hudolin's method. The programme includedthree steps: (1) presentation of the programme to the alcoholicfamily (four meetings); (2) a therapeutic community that metweekly over 4 months; and (3) attendance at an on-TreatmentAlcoholic Club located close to the family's home residence(weekly self-conducted meetings). Data on the families' complianceto the treatment programme were obtained in January 1993 andthe prognostic significance of 11 variables collected duringthe first step was determined by the proportional hazards regressionmodel. The cumulative proportion of family compliance after40 months was 36.4%, with similar drop-out rates at each ofthe three steps of the programme. The prognostic factor whichwas the major determinant of family compliance to treatmentwas the active presence of the whole family in the first step,while a good job performance was independently associated withfamily compliance, being a significant prognostic factor inthe second step of the programme. Alcohol abstinence was obtainedin 35.9% of the whole study group. This programme provided resultsfor alcohol abstinence which are comparable with methods thatrequire more expensive resources.     

Strong association between an HLA-DR antigen and thyroid carcinoma

A group of 20 patients affected with thyroid carcinoma, all from Southern Italy, was typed for HLA-A,-B,-C and -DR antigens. Sixteen of them (80%) typed for DR1, while in the control group (120 unrelated healthy individuals from the same region) only 22 (18.3%) shared the same antigen ( x ²2 = 32.96). The data indicate a highly significant association between the HLA-DR1 gene and the thyroid carcinoma.     

A crystal-state,solution and theoretical study of the preferred conformation of linear Cα,α-diphenylglycine derivatives and dipeptides with potential anticonvulsant activity

Several linear molecules containing the C^α,α-diphenylglycine residue were prepared as potential anticonvulsants. The conformational preferences of the C^α,α-diphenylglycine residue were assessed in these synthetic derivatives and dipeptides by X-ray diffraction, FTIR absorption and ¹H NMR techniques, and by conformational energy computations. Five (out of six) derivatives adopt the fully extended C₅ conformation in the crystal state. This intramolecularly H-bonded form is largely populated in chloroform solution in all the derivatives investigated. Conformational energy computations in vacuo support the view that the intramolecularly H-bonded C₇-ring form is the most stable structure for these compounds. Only one linear derivative exhibits a (modest) anticonvulsant activity.     

All-trans retinoic acid shows multiple effects on the survival, proliferation and differentiation of human fetal CD34+ haemopoietic progenitor cells

Summary. To evaluate the effect of all-trans retinoic acid (RA) on fetal haemopoiesis, we performed serum-free liquid and semisolid cultures using CD34⁺ cells purified from mid-trimester human fetal blood samples. RA, at both physiological (10^-n and 10^-12M) and pharmacological (10^-6 and l(r⁷M) concentrations, significantly (P<0.01) promoted the survival of fetal CD34⁺ cells in liquid cultures from day 3 onwards, by suppressing apoptosis induced by serum and growth factor deprivation. On the other hand, RA alone had no significant effect on the proliferation and differentiation of fetal haemopoietic progenitors. In the presence of optimal concentrations of recombinant interleukin-3 (IL-3), stem cell factor (SCF), granulocyte/ macrophage-colony stimulating factor (GM-CSF), and erythropoietin (Epo), low and high doses of RA induced striking differential effects on CD34⁺ cell proliferation in liquid cultures and colony formation in semisolid assays. In fact, 1CT^U M and 1CT¹²M RA were able to: (i) significantly (P<0.05) increase ³H-thymidine uptake by fetal CD34⁺ cells in liquid cultures, and (ii) variably promote the growth of pluripotent (CFU-GEMM, P<0.05), early (BFU-meg) and late (CFU-meg, P<0.01) megakaryocyte, granulocyte/macrophage (CFU-GM. P<001) and erythroid (BFU-E) progenitors in semisolid cultures. On the contrary, 10^-6 and 10^-7 M RA induced: (i) an overall inhibition (P<0.01) of CD34⁺ cell growth in liquid cultures; (ii) a marked suppression of BFU-E colony formation (P<0.01) at all Epo concentrations examined (0-002-4IU/ml); and (iii) a significant (P<0.()1) stimulation of CFU-GM with a shift from mixed granulocyte/ macrophage to pure granulocyte colonies, whereas it had little effect on the growth of CFU-GEMM, BFU-meg and CFU-meg. Our data, as a whole, demonstrate that RA has direct complex effects on the survival, growth and clonal expansion of fetal haemopoietic progenitor cells, mainly depending on the presence of recombinant cytokines, the type of progenitor and the concentrations of RA.     

Bioorganic stereochemistry. A study of the peptide oxazolones from Z-(Aib)n-OH (n = 2–4) in the solid state*

An investigation of the preferred conformations and modes of self-association of the peptide oxazolones from Z(-Aib-)_n-OH (n = 2–4) in the solid state has been performed by infrared absorption. More detailed information on the peptide oxazolone from Z(-Aib-)₃ OH (2) has been obtained using X-ray diffraction. In this compound the conformations of the first two Aib residues differ substantially, only the N -terminal one being found in the usual 3_10- (or α-) helical region of the Ramachandran map. The C=N-bond of the oxazolone group is not conjugated with the lactone moiety. A very weak intermolecular interaction occurs between the urethane N-H and the carbonyl group of the oxazolone ring.