Structural and Solution Characterization of Mononuclear Vanadium(IV) Complexes That Help To Elucidate the Active Site Structure of the Reduced Vanadium Haloperoxidases.

The complexes [VO(H(2)O)ada] (1), [VO(H(2)O)Hheida] (2), and [VO(H(2)O)aeida] (3) (H(2)ada, N-(carbamoylmethyl)iminodiacetic acid; H(3)heida, N-(2-hydroxyethyl)iminodiacetic acid; H(2)aeida, N-(2-aminoethyl)iminodiacetic acid) were synthesized and crystallographically characterized. Crystallographic parameters for 1.2H(2)O: monoclinic, space group P2(1)/c (No. 14), a = 7.327(2) Å, b = 23.386(7) Å, c = 7.258(3) Å, alpha = 90 degrees, beta = 110.95(2) degrees, gamma = 90 degrees, V = 1204.6(7) Å(3), Z = 4, R1 = 0.0353, and wR(2)() = 0.0848. Crystallographic parameters for 2.H(2)O: orthorhombic, space group Pbca (No. 61), a = 10.512(2) Å, b = 11.727(2) Å, c = 16.719(5) Å, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V = 2060.6(8) Å(3), Z = 8, R1 = 0.0297, and wR(2)() = 0.0758. Crystallographic parameters for 3: monoclinic, space group P2(1)/c (No. 14), a = 6.785(1) Å, b = 9.714(2) Å, c = 14.959(2) Å, alpha = 90 degrees, beta = 95.12(1) degrees, gamma = 90 degrees, V = 982.2(3) Å(3), Z = 4, R1 = 0.0298, and wR(2)() = 0.0762. In each structure, the tetradentate ligand is disposed so that the tertiary nitrogen is bound trans to the vanadyl oxo, and the rest of the donors occupy equatorial coordination positions. In solution, the structural integrity of these compounds is maintained as observed by UV/visible and EPR spectroscopies, and axial ligation by nitrogen is inferred on the basis of ESEEM spectroscopy. The implications of this study with respect to understanding the coordination environment of VO(2+) in the reduced, inactive form of vanadium bromoperoxidase (VBrPO) are discussed, and it is proposed that significant changes in the coordination environment of vanadium in VBrPO occur upon its reduction, which may provide a plausible explanation for its irreversible inactivation.

Visually impaired infants in the 1980s. A survey of etiologic factors and additional handicapping conditions in a school population.

To identify etiologic factors and ophthalmologic diagnoses related to visual impairment in young infants, a survey was carried out within the 22 school districts providing educational services to all visually impaired infants, birth to 3 years of age, in Harris County, Texas. Review of 102 records revealed that 51 percent had impaired vision associated with prenatal factors, and 31 percent were associated with perinatal events. The most frequent ophthalmologic diagnoses were lesions of the optic nerve, optic pathway, and visual centers of the brain (cortical blindness). A majority of the infants had multiple handicaps: 17 percent had hearing loss, 48 percent had cerebral palsy, 46 percent had seizures, and 78 percent had severe developmental delay. The high incidence of multiple handicaps and significant medical problems indicates the necessity for interface between physicians and educators who serve the visually impaired infant.

The longitudinal course of congenital rubella encephalitis in nonretarded children.

The neurologic course of congenital rubella syndrome was traced in 29 nonretarded children to 9 to 12 years. During the first two years, manifestations involved abnormal tone and reflexes (69%), motor delays (66%), feeding difficulties (48%), and abnormal clinical behavior (45%). Hearing loss was documented in 76%. From three to seven years, poor balance, motor incoordination (69%), and behavioral disturbances (66%) predominated. Hearing losses increased to 86%. Currently, at 9 to 12 years, 25 have residua which include learning deficits (52%), behavioral disturbances (48%), poor balance (61%), muscle weakness (54%), and deficits in tactile perception (41%). Two additional children now have hearing loss. The encephalitic manifestations of congenital rubella syndrome are diverse. Overriding problems differ at each phase of childhood. Current deficits influence progress in educational and home environments. For these children, adequate intelligence alone does not guarantee academic success.