Organization of receptive fields of tonic and phasic neurons of the pulvinar in the cat

The receptive fields (RF) of 163 neurons of the pulvinar were investigated by the method of point testing the RF surface with a stationary, flashing light spot. The RFs of 26% of the neurons were characterized by a phasic pattern of response in all regions studied, while the RFs of 15% of the neurons consisted of only tonic elements. A complex RF organization, consisting of tonic and phasic subfields, was characteristic of 59% of the neurons. On the basis of this fact the postulate is advanced concerning the convergence of two types of afferents on a single pulvinar neuron. The cell population receiving inputs from purely tonic or purely phasic afferents comprises 41% of all cells investigated. The measurement of the latent periods of neuron responses to a stationary, flashing light spot showed that neurons with a phasic type of response are distinguished by a shorter latent period compared to neurons with tonic and mixed types of responses.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 69, No. 1, pp. 19–25, January, 1983.     

Linkage disequilibrium analysis of childhood-onset spinal muscular atrophy (SMA) in the French -- Canadian population

Spinal muscular atrophy (SMA) is, after Duchenne muscular dystrophy,the most common neuromuscular disorder in childhood. The generesponsible for childhood SMA has been mapped to the q11. 2– q13. 3 region of chromosome 5. We have extended ourlinkage studies of SMA In the French - Canadian population toInclude microsatellite markers at the D5S125, D5S351, D5S435,JK53CA1/ 2 and MAPI B locl. These markers span about 4 cM ofthe SMA candidate region. We observed significant evidence forlinkage between SMA and all the markers tested. The analysisof recombinant chromosomes provide evidence for the followinggenetic order: D5S125-D5S435-MAP1B-3'-JK53CA1/2 and places D5S351proximal to JK53CA1/2. Furthermore, we confirm the current localizationof the SMA gene distal to D5S435. Finally, we provide demonstrationof significant linkage disequilibrium between childhood-onsetSMA and four of the five marker loci, D5S125, D5S435, D5S351and JK53CA1/2. Analysis of SMA-region haplotypes suggests thatthere may be a predominant SMA allele that is present on about17% of SMA chromosomes in this sample of the French - Canadianpopulation. We conclude that the observed linkage disequilibriumis likely due to genetic drift among regions of Quebec, consistentwith this population's early history.     

Identification of a latent state arising in the hippocampus following the cessation of long-term potentiation

The possibility of the restoration of long-term potentiation in the CA1 region and the dentate gyrus of the hippocampus during stimulation respectively of the dorsal raphé nuclei and locus coeruleus, with stimulus parameters inducing behavioral reactions, was investigated in freely-behaving rats. It was demonstrated that stimulation of the locus coeruleus, which was ineffective prior to the tetanization of the perforant path, led to the restoration of extinguished long-term posttetanic potentiation in the dentate gyrus of the hippocampus induced by tetanization of the perforant path. Stimulation of the dorsal raphé nucleus, which was ineffective prior to the tetanization of the Schaffer collaterals, led to the restoration of long-term posttetanic potentiation in the CA1 region of the hippocampus induced by tetanization of the Schaffer collaterals. A mathematical model is proposed which has made it possible to describe the restoration of long-term posttetanic potentiation on the basis of the notion of the existence of several states of calcium/calmodulin-dependant protein kinase. The restoration of long-term potentiation during stimulation of emotiogenic zones was examined as a model of the phenomenon of emotional reminding. Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I.P. Pavlova, Vol. 43, No. 4, pp. 770–777, July–August, 1993.     

Syndemic Health Disparities and Sexually Transmitted Infection Burden Among Black Men Who Have Sex with Men Engaged in Sex Work in the U.S.

Archives of Sexual Behavior - Black men who have sex with men (MSM) engaged in sex work (BMSM-SW) experience elevated HIV and sexually transmitted infection (STI) prevalence. Further, BMSM-SW have...     

P53 overexpression as an indicator of overall survival and response to treatment in osteosarcomas

The p53 gene located at chromosome 17pl3 is found to be altered (allelic loss or other mutation) in multiple human cancers, including osteosarcomas. The mutated gene produces a protein with a prolonged half-life thus rendering it detectable by conventional immunohistochemistry. We examined the correlation between p53 expression and clinical prognosis as well as response to therapy. Twentyone patients with previously untreated and histologically verified highly malignant osteosarcoma were used for this study. Biopsy material taken both prior to the start of COSS 91 protocol and at the time of surgery (ten weeks later) was examined for alterations in p53 protein expression and drug resistance. Two patients who had strong (+++) p53 protein expression and three others who became positive during the chemotherapy had significantly worse prognosis (all of them died within one year) than those who showed no p53 expression both at biopsy and after chemotherapy (all 11 patients are alive, average follow-up time: 3.5 years). All patients who showed any kind of positive p53 protein expression on initial biopsy were non-respon-ders to chemotherapy. In contrast, 69% (9 out of 13) of those who exhibited no p53 expression on initial biopsy were responders or intermediate responders to chemotherapy. We concluded that p53 expression may be a useful prognostic factor in osteosarcomas. The direct correlation between p53 positive expression and resistance to therapy can help in identifying patients who are in need of a more vigorous or different chemotherapeutical protocol.     

A trace element preparation increases antitumor activity in mice

A trace element preparation (Béres Drops Plus, BDP) produced immunomodulatory effects in previous in vitro and in vivo experiments. Here, C57B1/6 inbred mice were transplanted with either Lewis lung tumor or with B16 melanoma. BDP was given intraperitoneally a. before transplantation; b. after transplantation or c. after the removal of the primary tumor. As a result, BDP pretreatment could slow down the tumor progression by decreasing the number and the volume of metastases as well as the proportion of mice with metastases without influencing the growth of the primary tumors. Furthermore, BDP treatment improved the immunological activity of the tumor-bearing host, too. These preliminary data suggest that the parenteral administration of the practically non-toxic BDP could help to control tumor progression in experimental models.     

Blood filtration through polymer gauze filters

Translated from Khimiko-Farmatsevticheskii Zhurnal, No. 10, pp. 68–71, September–October, 1991.     

Effect of chronic clonidine treatment on the turnover of noradrenaline and dopamine in various regions of the rat brain

Summary The turnover of noradrenaline (NA) and dopamine (DA) was estimated in various rat brain regions by measuring the depletion of the amines after inhibition of their biosynthesis by -methyltyrosine. Acute treatment with clonidine (0.1 mg/kg) reduced NA turnover in the brain stem, hypothalamus and rest of the brain but had no effect on DA turnover in the corpus striatum and rest of the brain. After chronic clonidine treatment (0.1 mg/kg, twice daily for 15 days), NA turnover was not affected by an additional injection of clonidine in the brain stem or in the hypothalamus but was still markedly reduced in the rest of the brain. In addition, DA turnover was reduced in the corpus striatum and rest of the brain, an effect which was also observed after a single injection of a high dose of clonidine (1 mg/kg). These findings suggest that a chronic administration of clonidine may cause regionally differential changes in the sensitivity of central NA receptors.