Reorganization of human cortical maps caused by inherited photoreceptor abnormalities

We describe a compelling demonstration of large-scale developmental reorganization in the human visual pathways. The developmental reorganization was observed in rod monochromats, a rare group of congenitally colorblind individuals who virtually lack cone photoreceptor function. Normal controls had a cortical region, spanning several square centimeters, that responded to signals initiated in the all-cone foveola but was inactive under rod viewing conditions; in rod monochromats this cortical region responded powerfully to rod-initiated signals. The measurements trace a causal pathway that begins with a genetic anomaly that directly influences sensory cells and ultimately results in a substantial central reorganization.     

A cooling system for prostaglandin infusions

A simple system has been developed-for the prolonged infusion of an iced solution of prostacyclin (PGI₂). In a 24 h period at pH 10, there is a theoretical loss in activity of 6%, while a 5 h infusion leads to a 2% reduction in activity. The stability of the cooling system was demonstrated in six dog experiments where mean arterial pressure (MAP) was reduced to 58±3.8 Torr (x±SEM) over a 5 h period of infusing 500 ng/kg/min. In a saline medium, at 3°C, a 5 h PGI₂ infusion led to a stable reduction in MAP, whereas, at a temperature of 24°C, a 70 loss of infusate activity was noted. Supported in part by The National Institute of Health, Grant No. GM24891-04; The U.S. Army Medical Research and Development Command, Contract No. DAMD17-78-C-8026; The Brigham Surgical Group, Inc., and The Trauma Research Foundation.     

Changes in the nuclear uptake and retention of 3H-estrogen in gonadotrophs and lactotrophs as a function of age

A quantitative autoradiographic immunocytochemical study was performed in which the nuclear uptake and retention of 3H-estradiol (3H-E2) by luteinizing hormone (LH) and prolactin (PRL) cells was examined in 19-21-year-old baboons. 3H-E2 concentrating cells were found in all of the three lobes of the pituitary in varying percentages (38.7%, pars distalis; 17.1%, pars intermedia; 6.3%, pars nervosa). Approximately 80% of PRL cells and nearly 100% of LH cells were labeled. A count of the number of silver grains over nuclei revealed a marked variation of the accumulation of 3H-E2 by LH cells and to a lesser extent in PRL cells. These results suggest functional heterogeneity among LH and PRL cells. The present results are discussed in relation to the physiological state of old animals.     

Systematic investigations on the reactivity of oxazolinium salts

The termination reaction of the cationic polymerization of 2-phenyl- and 2-nonyl-2-oxazolines was examined by reacting the corresponding model oxazolinium salts having tosylate and trifluoromethansulfonate counterions with various nucleophiles. The reaction was monitored by ¹H NMR spectroscopy. Piperidine and KOH react with the oxazolinium salts very fast and quantitatively. In the case of piperidine, the use of a double molar amount of piperidine is necessary to achieve complete conversion. The addition of piperidine, pyridine, 4-dimethylaminopyridine and morpholine takes place in position 5 of the oxazolinium ring, whereas water and KOH add in position 2. The rate of the termination reaction depends on the electron density of the nucleophile which can be correlated with the pK_a value. With CF₃SO as counterion the addition of nucleophiles in position 5 is distinctly faster, whereas the addition of water in position 2 is much slower than with TsO^? as counterion. The ring-opening of the nonyl oxazolinium ion is slower than that of the phenyl oxazolinium ion.     

Stress and dental caries in the rat

The stress of crowding and exposure to inescapable electric shock increased both the incidence and the severity of dental caries in rats housed in a conventional animal facility. Male Osborne-Mendel rats were inoculated intraorally with cariogenic bacteria, fed a high-sucrose diet, and housed in either a conventional or a sheltered facility. Rats in both housing conditions were subdivided into control and stress groups. At the end of the 56-day trial period, stressed rats from conventional housing had a significant increase in both incidence and severity of dental caries in comparison to their controls. In contrast, stressed rats from sheltered housing had a trend toward increased cariogenesis which reached significance in only one of five scores. These rats also failed to gain weight comparable to their controls, making it possible that stress-induced reduction in appetite partially offset stress-induced exacerbation in cariogenesis.This investigation was supported in part by the following Grants from the United States Public Health Service: CA 20093, HL 22727, and HL 07374.     

Expression of a bacterial aspartase gene in Aspergillus nidulans: an efficient system for selecting multicopy transformants

Summary The Escherichia coli aspartase gene aspA has been expressed in the fungus Aspergillus nidulans using the powerful constitutive gpdA promoter and trpC terminator, both from A. nidulans. Multiple, but not single, copies of aspA overcome nutritional deficiencies resulting from the loss of catabolic NAD-linked glutamate dehydrogenase. They also circumvent certain nutritional deficiencies resulting from loss of the positive-acting regulatory gene product mediating nitrogen metabolite repression. Both of these cases of physiological suppression involve the aspartase-catalyzed catabolism of aspartate to ammonium plus fumarate. No physiological evidence for the opposite reaction leading to aspartate synthesis was obtained as multiple copies of aspA did not affect the phenotype resulting from the loss of anabolic NADP-linked glutamate dehydrogenase. The use of vectors containing aspA and recipients lacking NAD-linked glutamate dehydrogenase is an efficient means of selecting multicopy transformants in A. nidulans and also offers the possibility to select strains having increased aspartase levels from original transformants.     

Small reduction of capsaicin-induced neurogenic inflammation in human forearm skin by the glucocorticoid prednicarbate

Capsaicin applied to human skin provokes a response known as neurogenic inflammation. Neuropeptides (substance P, CGRP), released from afferent C-fiber terminals and histamine, secondarily released from mast cells, are supposed to participate in this reaction. We investigated the contribution of arachidonic acid and metabolic products to neurogenic inflammation, using a potent topically applied glucocorticoid and the corresponding vehicle. Arachidonic acid is liberated from membrane phospholipids by phospholipase A₂, an enzyme that can be blocked by glucocorticoids. In 12 healthy volunteers, neurogenic inflammation was induced by capsaicin 1% on both upper forearms after 16 h of topical pretreatment with either prednicarbate or vehicle. Neurogenic inflammation was assessed by laser Doppler flowmetry and by planimetry of flare sizes. Prednicarbate significantly reduced the laser Doppler flow values inside the flare responses, as well as the flare sizes themselves. These results show that to some extent glucocorticoids reduce capsaicin-induced neurogenic inflammation.     

Integration of target and effector information in human posterior parietal cortex for the planning of action

Recently, using event-related functional MRI (fMRI), we located a bilateral region in the human posterior parietal cortex (retIPS) that topographically represents and updates targets for saccades and pointing movements in eye-centered coordinates. To generate movements, this spatial information must be integrated with the selected effector. We now tested whether the activation in retIPS is dependent on the hand selected. Using 4-T fMRI, we compared the activation produced by movements, using either eyes or the left or right hand, to targets presented either leftward or rightward of central fixation. The majority of the regions activated during saccades were also activated during pointing movements, including occipital, posterior parietal, and premotor cortex. The topographic retIPS region was activated more strongly for saccades than for pointing. The activation associated with pointing was significantly greater when pointing with the unseen hand to targets ipsilateral to the hand. For example, although there was activation in the left retIPS when pointing to targets on the right with the left hand, the activation was significantly greater when using the right hand. The mirror symmetric effect was observed in the right retIPS. Similar hand preferences were observed in a nearby anterior occipital region. This effector specificity is consistent with previous clinical and behavioral studies showing that each hand is more effective in directing movements to targets in ipsilateral visual space. We conclude that not only do these regions code target location, but they also appear to integrate target selection with effector selection.     

Pregnancy outcome after blastocyst transfer as compared to early cleavage stage embryo transfer

BACKGROUND: Retrospective cohort study to evaluate differences in outcome when embryo transfer was performed either on day 2-3 (cleavage stage, CS-group) or on day 4-5 (blastocyst stage, BS-group). METHODS: A total of 1259 consecutive cycles yielding 500 live born babies performed at a single centre in Bregenz, Austria, were included. Main outcome measures were implantation and (multiple) pregnancy rates and neonatal outcome including birth defects. RESULTS: Total Pregnancy rate was 44% vs 28% (P < 0.001) and the total 'take home baby rate' was 37% vs 22% in the BS-group and the CS-group, respectively. Rate of multiple gestations (34% vs 17%, P = 0.001) was significantly higher among the BS-group, resulting in a higher rate of preterm deliveries < 36 weeks (26% vs 17%, P = 0.045). Female factor causing infertility (40% vs 21%, P < 0.001) was significantly higher among the BS-group. For the CS-group, rate of singleton pregnancies (83% vs 66%, P = 0.001) and idiopathic cause of infertility (34% vs 22%, P = 0.012) were significantly higher. No statistically significant differences were found in sex, Caesarean section rate, Apgar score and umbilical artery pH-values, total mean birth weight, admission rate to intensive care unit, days of hospitalization and number of minor and major birth defects. CONCLUSIONS: Our data suggest that blastocyst transfer may lead to a higher pregnancy rate with an overall better take-home baby rate (THBR) at the cost of higher rates of multiples and preterm deliveries.