Rigid rods with flexible side chains — A route to molecular reinforcement?

Liquid-crystalline main-chain polyesters with polystyrene side chains of different length and number per main chain were synthesized using aromatic hydroxyfunctional polystyrene (PS) macromonomers, terephthalic acid derivatives and tert-butylhydroquinone as co-diol. The molecular weight of the polystyrene side chain was varied in the range from 1000 to 20000. The influence of this novel type of substituent on the solubility, thermal behaviour and miscibility with PS as a flexible matrix polymer is discussed. The properties of the new compounds are compared to those of the respective homopolyester. The graft copolyesters are, depending on the characteristics of the polymeric substituent, soluble in common organic solvents and their thermal transition points are lowered compared to the homopolyester. Compared to blends of the homopolyester, the improvement of miscibility of the polymer-substituted rigid rods with PS as an example for a flexible matrix polymer can be valued as a step to molecular reinforcement.     

Goldenhar’s Syndrome associated with congenital cyanotic heart disease

A case of Goldenhar’s Syndrome in a 10 year old girl is reported. The unusual features are the absence of epibulbar dermoid which is one of the major hallmarks of the Syndrome and the presence of an associated Cyanotic Heart disease.     

Handcuff neuropathies

Compressive neuropathy due to tight application of handcuffs occurred in 5 patients. The superficial radial nerve was affected in 8 hands and the median nerve in two. Neurologic deficits persisted as long as 3 years after handcuffing. Nerve conduction studies helped to exclude malingering and other diagnoses. All patients had been intoxicated when handcuffed or had been arrested with force. The handcuff mechanism, which allows accidental overtightening after application, is an unrecognized factor in these neuropathies.     

Role of pylorus in mediating cholecystokinin-stimulated satiety in the Zucker rat

Obese Zucker rats are less responsive than their lean littermates to the effects of cholecystokinin-octapeptide on satiety and pancreatic growth and exocrine function. We hypothesized that the hyperphagia observed in obese Zucker rats may be caused by a decreased pyloric contractile response to cholecystokinin, resulting in an increased rate of gastric emptying, decreased postprandial gastric distention, and thus decreased satiety. Pyloric muscle strips from six obese Zucker rats and six lean littermates were mounted in separate tissue baths and isometric contraction was measured in response to acetylcholine and cholecystokinin-octapeptide. The dose-response curves for acetylcholine-and cholecystokinin-octapeptide-stimulated pyloric muscle contraction were similar for both the obese and the lean rats. (For cholecystokinin, D₅₀ obese=4.0±0.6 nM, D₅₀ lean=3.4±0.2 nM;P=0.16). We conclude that the decreased satiety response to cholecystokinin-octapeptide observed in obese Zucker rats is not secondary to a decreased pyloric responsiveness to cholecystokinin.This work was supported by NIH grant AM28303-03.