Fluorescence/Raman intensity ratio for monitoring the pathologic state of human lens

The authors have put quantitation of human lens fluorescence on a rational basis by using the accompanying Raman signal from lens protein as a normalization factor. The intensity ratio, Fluorescence/Raman (F/R), may be used to compare lenses of different ages when the exciting wavelength is long enough to give a measurable Raman signal. In younger lenses excited at 457.9 or 514.5 nm, the F/R shows a log increase with age. Older lenses, above 60 years of age, excited at 647.1 nm give a steeply rising sigmoid curve. In developing this procedure, the authors found that for each lens there is a characteristic wavelength that is called the critical wavelength (lambda critical). At wavelengths longer than lambda critical the Raman signal appears in the absence of a broad fluorescence peak; at shorter wavelengths the fluorescence intensity increases enough to overwhelm the Raman signal. For normal lenses, clear and not heavily pigmented, the lambda critical is age dependent, giving a curve that is a flattened sigmoid approximating a straight line.

Agonadism with positive H-Y antigen

A 30-year-old phenotypic female was investigated because of absence of the vagina. Her serum gonadotropins were elevated while testosterone was in the normal range for females. Stimulation with human chorionic gonadotropin (hCG) gave no response of testosterone. No uterus, Fallopian tubes, Wolffian derivatives, or the gonads were found at laparotomy. Chromosome analysis showed a 46,XY karyotype. The expression of the H-Y antigen was positive. The results suggest that testicular degeneration in agonadism is not caused by a defective H-Y antigen.

Fluorophors and chromophors from rat lens crystallins in UV with hydroxykynurenine

Isolated alpha-, beta-, and gamma-crystallins from young rat lenses were incubated in solution for 16 hr with 3-hydroxykynurenine under ultraviolet (366 nm) light. Controls included: incubation without light, without kynurenine, and with 2-mercaptoethanol. These procedures generated several chromophors (with absorption maxima or shoulders at 340, 370, and 470 nm) and fluorophors (with excitation/emission at 407/515, 458/550, 515/555, 647/664, and 647/740 nm). The formation of these pigments was inhibited by 2-mercaptoethanol. The findings are discussed in relation to the chromophors and fluorophors found in aged and brunescent human lenses.

Metabolic production of a blue-green fluorophor in lenses of dark-adapted mice and its increase with age

A blue-green fluorophor (496 nm emission/406.7 nm excitation) occurs in the mouse lens; its increase with age is more pronounced in the nucleus than in the cortex. The level of fluorophor and its rate of production are the same for animals reared in the dark as for animals reared in the light. Thus, the fluorophor is not generated by a photochemical reaction but is a purely metabolic product.

Role of the posterior hypothalamus in the development of acute brain swelling

Destructive stereotaxic lesions were made in the posterior hypothalamus, unilaterally or bilaterally, in 26 dogs. In 21 dogs the intracranial pressure (ICP) was maintained in normal range, and in five dogs the ICP was artificially elevated to 300 to 400 mm h2o, preceding the procedures to the hypothlamus. Arterial oxygen and carbon dioxide pressure ((PaO2 and PaCO2) were maintained in the normal range. Before and after each procedure, systemic arterial pressure (SAP) was elevated by intravenous injection of norepinephrine (5 X 10(-3) mg/kg) to determined whether the ICP increases coincidentally with elevation of the systemic arterial pressure. The intracranial pressure/mean arterial pressure ratio of elevation by injection of norepinephrine was not significant regardless of the level of the ICP, or of uni-or bilateral lesions of the hypothalamus. The authors conclude that dysfunction of posterior hypothalamus does not play a specific role in the development of vasomotor paralysis leading to acute brain swelling, under conditons of normal or moderately raised ICP with normal PaCO2 and Pato2 levels.