Demonstration and topographical distribution of LHRH receptors in the central nervous system in the normal and castrated male rat

The topographical distribution of [125I]-LHRH binding sites was studied on brain sections of adult male rat by quantitative autoradiography. High density of sites was observed in the hippocampus, amygdala and entorhinal cortex (4-7 fmol of LHRH bound/mg protein). Lower density of sites was observed in the septum and frontal cortex. The receptor density was not significantly modified at day 5 following castration. Under the same conditions the pituitary receptors were significantly increased. The presence of specific LHRH binding sites in the limbic system may explain the behavioural effect observed following intracerebroventricular injection of LHRH. However, their functions under physiological conditions remain to be elucidated.     

Neuronal transformations in Alzheimer's disease

Summary Brains of nine early and four advanced Alzheimer patients have been investigated, utilizing three approaches to specify the threshold state of Alzheimer's disease (AD). Extensive thin sectioning electron microscopy (EM) of frontal lobe biopsies, correlated with stringent clinical assessment, has demonstrated that the neuronal cytoskeleton undergoes specific transformations into paired helical filament-like (PHF-like) strands, which lead to the formation of the insoluble paracrystalline paired helical filaments (PHFs). The neurofilamentous network (NFN) transformation plays an important role in this process, whereby segregation, posttranslational modifications and reassembly of the modified components through autocrosslinking, and phase transition occur. According to our data, the threshold state can be defined as the state of irreversible segregation and posttranslational modification of the NFN and the microtubule-associated proteins. At this state, therapeutic intervention to reverse the disease process may be possible. The results indicate similarities between the formation of the paracrystals of the PHFs and the formation of the tropomyosin-like crystals of the Hirano bodies. Close relationships among PHFs and smooth endoplasmic reticulum and plasma membrane do exist. Enveloped virus-like particles have been observed in neurons containing PHFs. A possible role of these virus-like particles as an etiological agent for AD is discussed.     

In vivo measurement of spectroscopic and photochemical properties of intact leaves using the ‘mirage effect’

This paper describes a new, highly sensitive, method for in vivo studies of photosynthesis based on the ‘mirage effect’ in which thermal energy dissipation from intact leaves, illuminated with intensity-modulated light, is sensed through the periodic deflection of a laser beam propagating along the leaf surface. The photothermal deflection technique allows one to rapidly estimate the gross efficiency of photochemical energy storage by comparing the heat emission signal with and without an additional strong, photosynthetically saturating, non-modulated light. In pea leaves, the maximal storage efficiency at low light intensities was shown to approach 55%. The general utility of this simple photothermal method is illustrated by examining the variation of the deflection signal under different conditions. The spectral resolution of this new method is shown to be much higher than that of the photoacoustic method.     

The warning leak in subarachnoid hemorrhage and the importance of its early diagnosis.

A 40-year-old man had a severe headache of sudden onset and progressive palsy of the third cranial nerve from a minor subarachnoid hemorrhage. Despite assessment by two primary care physicians the possibility of serious neurologic disease was not raised and the urgency of the situation not appreciated. Two weeks after the onset of the headache the patient was urgently admitted to hospital at the request of a neuro-ophthalmologist. Cerebral angiography revealed an aneurysm of the posterior communicating artery, which was surgically occluded with a clip. The patient had a satisfactory recovery, with almost complete return of nerve function by the time of discharge from hospital. Such "warning leaks" in subarachnoid hemorrhage are discussed, and a protocol for their assessment is recommended.     

Complex formation between chlorophyll a and cytochrome c: surface properties at the air-water interface. Absorbance, fluorescence and fluorescence-lifetime in Langmuir-Blodgett films.

The binding of cytochrome c to an insoluble monolayer of chlorophyll a was studied. Surface pressure (II), surface potential (delta V) and [14C]cytochrome c surface-concentration (gamma) isotherms were measured versus molecular area (sigma) in mixed films. Compared to the successive-addition method, this procedure allows the formation of homogeneous mixed films. The cytochrome c is incorporated into a chlorophyll a monolayer, compressed at a surface pressure of 20 mN.m-1. On expansion, the quantity of protein incorporated into the monolayer gradually increases. Subsequent compression-expansion cycles result in similar isotherms, distinct from that measured during the first expansion. All surface properties measured, but more specifically the surface radioactivity of [14C]cytochrome c, indicate the irreversibility of protein incorporation into the chlorophyll a monolayer. In fact, surface properties of the binary film are completely different from the properties of either of the pure components. As a result, calculated values of surface potentials for mixed films using the additivity law deviate from experimentally measured potentials. The absorption and fluorescence spectra of mixed films transferred onto a solid substrate by the Langmuir-Blodgett technique, indicate a dilution effect of chlorophyll a by cytochrome c. However, the dilution effect cannot be detected by the fluorescence lifetimes of pure chlorophyll a and mixed chlorophyll a-cytochrome c films, both shorter than 0.2 ns. This provides support for the existence of an energy-transfer mechanism between chlorophyll a monomer and chlorophyll a aggregates which could serve as an energy trap. The role of the protein could be related to that of the matrix.     

Possible interactions between neurotensin and prostaglandins in the isolated rat portal vein

Neurotensin (NT) was found to elicit a dose-dependent contractile effect in the isolated rat portal vein. This effect was not inhibited by phentolamine, atropine, methysergide, a mixture of diphenhydramine and cimetidine, or by [Leu⁸]-angiotensin II, but it was markedly reduced or abolished by various antiinflammatory drugs such as indomethacin, acetylsalicylic acid, mefenamic acid, hydrocortisone and by mepacrine, an inhibitor of phospholipase A₂. The concentrations of antiinflammatory drugs used to inhibit NT, also antagonized the venoconstrictor effects of bradykinin and angiotensin, but did not affect the responses of the vein to noradrenaline. [D-Trp¹¹]-NT, a previously described NT antagonist, was found to inhibit selectively and dose-dependently the stimulant effect of NT in the portal vein. The results suggest the existence of specific receptors for NT in the isolated rat portal vein. The response of this tissue to NT, and possibly to other peptides, appears to be dependent upon the presence of a functional PG biosynthetic pathway.     

Effects of Oxyphenbutazone (Tandearil) on Plasma Seromucoids. II. In Postoperative Inflammation

The efficacy of oxyphenbutazone (OPB) in the control of postoperative inflammation was investigated, and previous findings were extended on the rate at which the inflammatory response of plasma seromucoids was significantly modified by this drug. Eighty - five surgical patients (hemorrhoidectomy, 39; vaginal hysterectomy, 23; tonsillectomy, 14; submucosal resection of nasal cavity, 9) were studied by the double-blind method. OPB was administered orally in a daily dosage of 400 mg. with a priming dose on the evening before surgery. Effective control of postsurgical inflammation was achieved in 34 of 46 treated subjects as compared with similar results in eight of 39 controls. Control of postoperative pain was pronounced when OPB was used. One patient developed an urticarial rash. Chemical studies were carried out in 65 surgical patients (39 treated with OPB; 26 controls). In the postoperative phase, mean plasma seromucoid values increased from presurgical levels by 39% in controls and by 13.9% in OPB-treated subjects. Hence, results of this clinical trial clearly demonstrate the usefulness of OPB in the control of postsurgical inflammation. Moreover, results of the chemical studies are in accordance with those previously obtained in animals.     

Full length cDNA structure and deduced amino acid sequence of human 3 beta-hydroxy-5-ene steroid dehydrogenase

Polyclonal antibodies raised against 3 beta-hydroxysteroid dehydrogenase isolated from human placenta were used to screen a lambda gt11 expression cDNA library from the same tissue. The protein deduced from cDNA sequences contains 372 amino acids with a calculated mol wt of 42,216. Since 3 beta-hydroxysteroid dehydrogenase is the enzyme catalyzing the formation of all classes of hormonal steroids, the availability of the cDNA encoding this enzyme opens new possibilities for a detailed investigation of the factors regulating the expression and activity of this crucial enzyme in adrenal, gonadal as well as peripheral tissues.