Biomedical subjects

H G Mack

Publications and source records attributed to H G Mack.

5 recordsLinked to original sources

PubMed2001

Gas-phase structures of acetyl peroxynitrate and trifluoroacetyl peroxynitrate.

The molecular structures and conformational properties of acetyl peroxynitrate (PAN, CH3C(O)OONO2) and trifluoroacetyl peroxynitrate (FPAN, CF3C(O)OONO2) were investigated in the gas phase by electron diffraction (GED), microwave spectroscopy (MW), and quantum chemical methods (HF/3-21G, HF/6-31G*, MP2/6-31G*, B3PW91/6-31G*, and B3PW91/6-311+G*). All experimental and theoretical methods show the syn conformer (C=O bond of acetyl group syn to O-O bond) to be strongly predominant relative to the anti conformer. The O-NO2 bonds are extremely long, 1.492(7) A in PAN and 1.526(10) A in FPAN, which correlates with their low bond energy and the easy formation of CX3C(O)OO* and *NO2 radicals in the atmosphere. The O-O bonds (1.418(12) A in PAN and 1.408(8) A in FPAN) are shorter than that in hydrogen peroxide (1.464 A). In both compounds the C-O-O-N dihedral angle is close to 85 degrees.

Journal Article↗

PubMed2000

Tautomers and conformers of malonamide, NH2-C(O)-CH2-C(O)-NH2: vibrational analysis, NMR spectra and ab initio calculations.

The conformational and tautomeric compositions of malonamide, NH2-C(O)-CH2-C(O)-NH2 were determined by vibrational spectroscopy and theoretical calculations (HF/6-31G*, B3PW91/6-31G*). Solid state Fourier transform infrared and Raman spectra were analysed. They reveal the existence of a diketo tautomer. Theoretical calculations predict a diketo structure belonging to the C1 symmetry group. No enol form is present in the molecule in the solid. 13C-NMR studies show only signals of a diketo tautomer.

Magnetic Resonance Spectroscopy↗

PubMed1997

A search for a mammalian homologue of the Drosophila photoreceptor development gene glass yields Zfp64, a zinc finger encoding gene which maps to the distal end of mouse chromosome 2.

Whilst searching for a mammalian homologue of the Drosophila glass gene we cloned a mouse cDNA whose deduced sequence encodes a 614 amino acid (aa) protein with ten Cys2-His2 (C2H2) zinc finger (Zf) motifs. Zfp64 is expressed in all developing and mature mouse tissues examined, except the mouse erythroleukemia (MEL) cell line. Zfp64 maps to the distal region of mouse chromosome 2 close to lens opacity 4 (Lop4), a semidominant cataract mutation. Sequence analysis shows that Zfp64 has multiple potential phosphorylation sites for casein kinase II (CK II), protein kinase C (PKC), tyrosine kinase (TK) and c-AMP- and c-GMP-dependent protein kinase (cA/GMPDPK).

Amino Acid Sequence↗

PubMed1997

Isolated metastases to the retina or optic nerve.

Isolated metastases to the retina or optic nerve are extremely rare. Retinal metastases arise from cutaneous malignant melanoma and carcinomas (lung, gastrointestinal, genitourinary, and breast). Most patients present with reduced vision. The clinical appearance of these metastases is variable. Melanoma metastases are brown or black, whereas carcinoma metastases are white. Frequently, retinal hemorrhages and exudates are seen. Optic nerve metastases arise from carcinomas (lung, breast, and gastrointestinal) in adults and acute leukemias in children. As is true of retinal metastases, most patients present with reduced vision. Though in most cases there is a visible optic nerve mass, some patients have optic disc edema only. Investigations are directed by a known history of malignancy in many patients and by physical examination. Cytological workup of vitreous may be required. Treatment options include observation, radiotherapy in eyes with visual potential, and enucleation for pain control. The visual prognosis is poor. In patients with retinal or optic nerve metastases, median survival is approximately 9 months after the onset of visual symptoms, but is slightly longer in cases in which the primary lesion is breast carcinoma.

Adult↗

PubMed1991

Delayed choroidal perfusion in giant cell arteritis.

The fundus fluorescein angiograms of 13 patients with visual disturbance due to biopsy-proven giant cell arteritis (11 with anterior ischemic optic neuropathy (AION); 2 with visual obscurations only) were compared with the fluorescein angiograms from 33 patients with acute nonarteritic AION and 23 age-matched normal eyes. In all 13 patients with giant cell arteritis, the fluorescein angiograms showed a significant delay of choroidal filling time (mean 69 seconds) in comparison with either normal subjects (mean 5.8 seconds) or patients with nonarteritic AION (mean 5.5 seconds). In patients presenting with acute AION, the finding of delayed choroidal filling on fluorescein angiography should raise the index of suspicion of giant cell arteritis and lead to prompt investigation and treatment.

Acute Disease↗