Clinical Assessment of Gestational Age

There is disagreement among authors as to what criteria are most reliable in assessing postnatal fetal age. A comparison–for objectivity, accuracy, and frequency of use– of specific criteria was made using three independent examiners at different educational levels: a second-year medical student, a perinatal nurse practitioner, and a pediatrics resident. It was shown that trained examiners develop favorite criteria which differ among examiners and thus sacrifice accuracy; however, accurate assessment of fetal age can be accomplished by an examiner with minimum clinical knowledge.     

Working With Parents Through a Devastating Experience-The Birth of a Mongoloid Child

The author believes that professional advice given the parents of a mongoloid infant determines their initial decision on institutionalization. Multidisciplinary counseling by the health team can help parents decide on a course of action that will prove satisfactory in the long run. Consultation should include health t e r n efforts to help parents work through the mourning process and presentation of a) an objective, comprehensive view of the child's condition, b) information on integrating a mongoloid into the family unit, and c) outside resources available to the parents. Deliberation with the parents to help them reach their own decision is essential.     

Difficulties in Immunohaematology : The Weak D Antigen

Background

The Rh blood system is one of the most polymorphic and immunogenic systems known to humans. The expression of Rh blood group antigen is complex. The Rh D antigen is the most important of the antigens that constitute the Rh antigen system. In most cases, D antigen can easily be detected. However, due to variability of expression, weak forms antigen are encountered. The reactivity of weak D with antisera is variable and presents as a problem in blood banking.

Methods

A retrospective analysis for a five-year period was done. Blood samples that were negative for Rh D by immediate spin tube method were tested for weak D antigen by additional lab tests.

Result

Of 34932 serial Rh grouping tests done in our Blood Bank, the incidence of weak D Rh antigen was 0.189%. All these were confirmed by the antiglobulin test.

Conclusion

These patients present as a problem for the blood banker and a curiosity to the clinician. Although uncommon, all health care workers should be aware of this entity to avoid anti D alloimmunisation.Key Words: Weak D, Rh Blood Group     

Thermodynamics of Linear Poly(pentamethylene urethane) and Poly(hexamethylene urethane) in the Range from 0 to 450 K

Summary: The thermodynamic properties – the temperature dependence of heat capacity and the temperatures and enthalpies of physical transitions – of poly(pentamethylene urethane) and poly(hexamethylene urethane) have been studied over the range 6 to 450 K by precision adiabatic vacuum and dynamic calorimetry. Their energies of combustion, Δ_cU, have been measured in a calorimeter with a static bomb and an isothermal shield. The calorimetric data were used to determine the temperature dependences of the heat capacity = f(T) for poly(pentamethylene urethane) and poly(hexamethylene urethane) in crystalline and amorphous states, to calculate the thermodynamic parameters of the glass transition and the glassy state, the thermodynamic quantities of fusion and the thermodynamic functions (T), H⁰(T) ? H⁰(0), S⁰(T) ? S⁰(0) and G⁰(T) ? H⁰(0) of the polymers for the temperature range from 0 to 450 K. The enthalpy of combustion Δ_cH⁰ and the standard thermodynamic characteristics of formation, namely, the enthalpy, Δ_fH⁰, entropy, Δ_fS⁰ and Gibbs function, Δ_fG⁰, of the substances under discussion were estimated at T = 298.15 K. The regions of thermal resistance for the tested compounds were determined calorimetrically.

Temperature dependence of of poly(pentamethylene urethane)(A) and poly(hexamethylene urethane)(A′).