Perspectives on long-acting formulations of pre-exposure prophylaxis (PrEP) among men who have sex with men who are non-adherent to daily oral PrEP in the United States

INTRODUCTION

Pre-exposure prophylaxis (PrEP) persistence among men who have sex with men (MSM) in real world clinical settings for HIV prevention is suboptimal. New longer-acting formulations of PrEP are becoming available, including injectables, subdermal implants, and other oral medications. These longer-acting formulations have the potential to improve retention among those who have challenges remaining adherent to daily oral PrEP.

METHODS

We interviewed 49 MSM who had initiated but discontinued oral PrEP at three diverse clinics across the United States. We examined participants' perspectives about long-acting PrEP formulations and how long-acting options could affect PrEP use using thematic analysis.

RESULTS

Participants were not very knowledgeable about long-acting formulations of PrEP but were open to learning about them and considering use. Participants were concerned about safety and efficacy of products given that they were still newer and/or in development. Finally, participants had clear preferences for oral pills, injectables, and then subdermal implants and were most interested in options that reduced the number of visits to the clinic.

CONCLUSION

Long-acting formulations of PrEP are acceptable to MSM with suboptimal PrEP persistence and have the potential to improve PrEP persistence. However, many felt they needed more information on safety, efficacy, and use to consider these options. As these long-acting formulations are implemented, public health campaigns and clinical interventions to encourage may maximize uptake particularly among those who are not currently adherent to daily oral PrEP.

Facilitators for retaining men who have sex with men in pre-exposure prophylaxis care in real world clinic settings within the United States

BACKGROUND

Pre-exposure prophylaxis (PrEP) can significantly reduce HIV acquisition especially among communities with high HIV prevalence, including men who have sex with men (MSM). Much research has been finding suboptimal PrEP persistence; however, few studies examine factors that enhance PrEP persistence in real-world settings.

METHODS

We interviewed 33 patients who identified as MSM at three different PrEP clinics in three regions of the U.S. (Northeast, South, Midwest). Participants were eligible if they took PrEP and had been retained in care for a minimum of 6 months. Interviews explored social, structural, clinic-level and behavioral factors that influencing PrEP persistence.

RESULTS

Through thematic analysis we identified the following factors as promoting PrEP persistence: (1) navigation to reduce out-of-pocket costs of PrEP (structural), (2) social norms that support PrEP use (social), (3) access to LGBTQ + affirming medical providers (clinical), (4) medication as part of a daily routine (behavioral), and (5) facilitation of sexual health agency (belief).

DISCUSSION

In this sample, persistence in PrEP care was associated with structural and social supports as well as a high level of perceived internal control over protecting their health by taking PrEP. Patients might benefit from increased access, LGBTQ + affirming medical providers, and communications that emphasize PrEP can promote sexual health.

Characterization of the nontrivial and chaotic behavior that occurs in a simple city traffic model

We explore in detail the nontrivial and chaotic behavior of the traffic model proposed by Toledo et al. [Phys. Rev. E 70, 016107 (2004)] due to the richness of behavior present in the model, in spite of the fact that it is a minimalistic representation of basic city traffic dynamics. The chaotic behavior, previously shown for a given lower bound in acceleration/brake ratio, is examined more carefully and the region in parameter space for which we observe this nontrivial behavior is found. This parameter region may be related to the high sensitivity of traffic flow that eventually leads to traffic jams. Approximate scaling laws are proposed.

Postnatal development of cholinergic system in mouse basal forebrain: acetylcholinesterase histochemistry and choline-acetyltransferase immunoreactivity

The distribution of acetylcholinesterase histochemistry and choline-O-acetyltransferase immunohistochemistry in the basal forebrain was studied in newborn mice (P0) and until 60 days of postnatal life (P60). A weak acetylcholinesterase activity was found at P0 and P2 in the anterior and intermediate parts of the basal forebrain, and higher in the posterior region. The intensity of labeling, neuronal size and dendritic growth seems to increase progressively in all regions of basal forebrain from P4 to P10. The AChE+ cell count shows that in the anterior portion of the magnocellular basal nucleus the number of cells does not vary significantly from birth to the second month of postnatal life. However, in the intermediate and posterior portions of the nucleus the mean number of labeled cells increases significantly from birth to the end of the second week of postnatal life (P13). The choline-acetyltransferase immunoreactivity appears only detectable at the end of the first week (P6) as a slight immunoreaction, which increases progressively in intensity at P8, and at P10 seems to attain the same intensity of labeling found at P60. These results seem to indicate that the acetylcholinesterase could have a non-classic cholinergic role in the first stages of postnatal development, acting as a growth and cellular differentiation factor.

Acetylcholinesterase and butyrylcholinesterase histochemical activities and tumor cell growth in several brain tumors

BACKGROUND

The hydrolysis enzymes of the acetylcholine, acetylcholinesterase, and butyrylcholinesterase are involved in non-cholinergic functions such as proliferation processes and cellular adhesion. These enzymes have been found in several tumors other from brain tumors.

METHODS

Thirty fresh brain tumor specimens were obtained from biopsies taken during neurosurgical procedures. The specimens were cut in two parts, one designated for routine histopathological control and the other for histochemical and growth studies. The formalin fixed specimens were serially cut at 10 microm in a freezing cryostat, mounted in gelatin-coated slides, and processed for sensitive histochemical detection of acetylcholinesterase and butyrylcholinesterase. The other specimens were processed for a HMEM cell growth culture.

RESULTS

The results show the coexistence of acetylcholinesterase and butyrylcholinesterase in all tumors studied. Type II and III gliomas and oligodendrogliomas show moderate activity of both cholinesterases, whereas in type IV glioma and meningiomas the labeling of both cholinesterases was high. In the craniopharyngiomas a high acetylcholinesterase activity was observed and low level of butyrylcholinesterase labeling. The cell growth was high only in the cases in which butyrylcholinesterase activity was high, such as type IV glioma. In type II and III gliomas, oligodendroglioma, and craniopharyngioma the growth rate was slow.

CONCLUSIONS

These results could indicate a possible relationship between the presence of butyrylcholinesterase and acetylcholinesterase in brain tumor tissue and cellular proliferation in tumorigenesis.

Postnatal development of the basal forebrain cholinergic projections to the medial prefrontal cortex in mice

The postnatal development of basal forebrain cholinergic projections to the medial prefrontal cortex in mice was analyzed by means of the double labeling track-tracing study. The tracer was injected into the medial prefrontal cortex of mice, on the day of birth (P0) to 60 days after birth. The total number of basal forebrain neurons increased from P4 to P8, and began to decrease until P13 (52.9% vs. the maximal average (P8)). After P13, the mean average remains stable up to P60. On the other hand, differential pattern of frontocortical projections of the anterior, intermediate, and posterior regions can be observed.

Mortality supposedly due to intoxication by pyrrolizidine alkaloids from Heliotropium indicum in a horse population in Costa Rica: a case report

This article describes a case of massive mortality among horses which was probably due to intoxication by pyrrolizidine alkaloids from Heliotropium indicum. Over 4 years more than 75% of a population of about 110 horses on a farm in Costa Rica died after showing nervous neurological symptoms. Two clinical manifestations were encountered, an acute and a chronic one, both with a fatal outcome. Pathological findings in 2 horses coincided with those reported in the literature for intoxication by pyrrolizidine alkaloids and were not specific for VEE. However Venezuelan equine encephalitis (VEE) was the main differential diagnosis and could not completely be excluded because this disease was endemic in the region and VEE titres were found to be high. Taxonomic and toxicological investigations implicated Heliotropium indicum as the most probable principal cause of the intoxication.

Dental fluorosis in Chilean children: evaluation of risk factors

The purpose of this case-control study was to determine the association between very-mild-to-moderate enamel fluorosis and exposure during early childhood to fluoridated water, mainly through ingestion of powdered milk. Analysis was performed on 136 residents of the optimally fluoridated community of San Felipe in the Chilean Fifth Region, who were categorised into one of three groups according to their age when water fluoridation was introduced in 1986: Group I was born after 1986; Group II was 16-24 months old in 1986; and Group III was >24 months of age. The case and control subjects were selected on the basis of a clinical examination given in July 1996. Dean's scoring system was used to determine fluorosis status. Risk factor exposure was ascertained by a questionnaire used in interviews with mothers of participating children. Logistic regression analysis, after adjustment for confounding variables, revealed that very-mild-to-moderate enamel fluorosis of permanent central maxillary incisors (CMI) was strongly associated both with the age of the subjects when water fluoridation began and with breast-feeding duration for children belonging to Group I. Subjects in Group I were 20.44 times more likely (95% CI: 5.00-93.48) to develop CMI fluorosis than children who were older than 24 months (Group III) when fluoridation began. Subjects who were between 16 and 24 months old when water fluoridation began were 4.15 times more likely (95% CI: 1.05-16.43) to have CMI fluorosis than children older than 24 months. An inverse association was found with breastfeeding duration (OR=0.86, 95% CI: 0.75-0.98) among Group I subjects but not in Groups II and III. Results obtained suggest that the current fluoride concentration in drinking water may be contributing to fluorosis. Further studies will be necessary to determine the relative competing risks of dental fluorosis and dental caries in Chilean children in order to establish the most appropriate water fluoridation level in Chile.

Estimation of optimal concentration of fluoride in drinking water under conditions prevailing in Chile

The purpose of this comparative study of caries and dental fluorosis experience in Chilean children was to estimate the optimal range of fluoride concentration in tap water under conditions currently prevailing in Chile. The sample included 2431 schoolchildren 7, 12 and 15 years old, life-long residents of five communities with fluoride concentrations in their tap water in the range 0.07-1.1 mg/L. The study population received an oral clinical examination including caries experience and an enamel fluorosis evaluation of the permanent dentition (Dean's scoring system). For 15-year-old children, the DMFT index changed from 5.06 to 2.60, and for 12-year-olds it changed from 3.10 to 1.36 when fluoride water concentration changed from 0.07 to 1.10 mg/L. For 7-year-old children the dmft index correspondingly changed from 3.67 to 1.59. The relationship between DMFT for 12-year-olds and water fluoride concentration was best fitted by a logarithmic function (r2=0.98). The Community Fluorosis Index (CFI) was used to assess enamel fluorosis in the study population, and it showed a linear relationship (r2=0.983) with increasing fluoride concentration of water for the 12-year-old group. Results obtained suggest that under current Chilean conditions, the optimal range of fluoride concentration in potable water should lie in the 0.5-0.6 mg/L range.

[Primary transitional cell carcinoma of the prostate. An infrequent tumor]

Primary prostatic carcinoma accounts for 2% to 4.5% of all neoplasias to this organ, and it has been observed in 2.8% of all radical cystoprostatectomies performed in the Mayo clinic. It originates in the poorly differentiated reservoir cells of the prostatic periurethral ductus which explains why diagnosis is most often obtained in advanced stages (stromal involvement), thus limiting its management to radical surgery. This paper contributes one case report of a patient diagnosed by transrectal biopsy of a primary prostatic transitional carcinoma presenting with incoercible rectorrahges and urinary obstruction symptoms. Treatment was through pelvic exenteration, and urinary and gut by-pass.

Demonstration of peptidergic afferents to the bed nucleus of the stria terminalis using local injections of colchicine. A combined immunohistochemical and retrograde tracing study

In the present study, we demonstrate the existence of numerous peptidergic afferents to the bed nucleus of the stria terminalis (BNST) using the retrograde transport of gold-labeled wheat germ agglutinin-apo-peroxidase (G-WGA-HRP) combined with the indirect immunoperoxidase method after intraparenchymatous injections of colchicine. At first, we show that local injections of colchicine alone into the BNST are able to induce the retrograde accumulation of peptides until the nerve cell bodies of origin, probably because of the blockade of axonal transport in nerve terminal arborizations innervating this nucleus. The actual existence of putative peptidergic afferents to the BNST indicated by the local injections of colchicine was established using: a) the retrograde transport of G-WGA-HRP from the BNST combined with immunocytochemistry after administration of colchicine at the same place, b) the anterograde "transport" of the fluorescent tracer DiI from selected nuclei of the forebrain. We demonstrate that the neurons immunoreactive for enkephalins, neurotensin, or substance P that innervate the BNST are localized mainly in the central amygdaloid nucleus, the paraventricular thalamic nucleus, and the ventromedial hypothalamic nucleus ipsilateral to the injection, as well as bilaterally in the magnocellular paraventricular and perifornical regions of the hypothalamus. From these results it may be concluded that intracerebral injections of colchicine constitute a powerful tool to search for multiple peptidergic afferents to a given brain nucleus using only immunohistochemistry. The existence of these pathways, however, must be verified by other neuroanatomical methods because of the problem of nerve fibers of passage.

[Effectiveness and safety of 150 mg vs 300 mg ranitidine twice a day in duodenal ulcer]

394 patients with endoscopically diagnosed duodenal ulcer were randomly allocated to treatment with ranitidine 150 bid o ranitidine 300 mg bid in a prospective double-blind multicenter trial conducted in seven LatinoAmerican countries. Endoscopy at 4 weeks showed complete ulcer healing en 171 of 196 patients (87.2%) treated with ranitidine 150 mg bid and 178 of 198 (89.9%) treated with ranitidine 300 mg bid. Both treatment regimens were equally effective at rapidly reducing the incidence of ulcer-related symptoms. It is possible that higher dosage regimen of ranitidine would be useful in patients with more severe duodenal ulcer disease.

Evaluation of two vaccines for the treatment of pythiosis insidiosi in horses

Two vaccines to treat phythiosis insidiosi in horses were evaluated in 71 Costa Rican horses between 1982 to 1988. One vaccine used a cell-mass (CMV) as antigen and the other a soluble concentrated antigen (SCAV). Both vaccines cured horses infected with Pythium insidiosum (p value approximately 14%). The age of lesions prior to vaccination was important in the response of the horses to immunotherapy. All horses with lesions 0.5 months or less in duration were cured regardless of the vaccine used. Horses with lesions two or more months old did not respond to either vaccine. The age of the horses did not have any influence on their response to the vaccinations. The CMV produced a prominent inflammatory reaction at the side of injection, while the SCAV gave a low inflammatory reaction. In addition, the CMV lost its effectiveness two to three weeks after its preparation. By contrast, the SCAV maintained its ability to cure horses even after 18 months. Immunotherapy using SCAV can thus be used as the vaccine of choice in early cases of equine cutaneous pythiosis insidiosi.

Employment of antipeptide antisera to distinguish two closely related cytokines induced in human T cells

AT464 and AT744 are two cytokines encoded by mitogen-induced genes from human T lymphocytes. These proteins belong to a family of structurally related chemotactic proteins associated with inflammation. By expression of their full length cDNAs in COS cells and in baculovirus-infected Sf9 cells, we found that pAT464 and pAT744 cDNAs represent secreted polypeptides of a molecular mass of about 8,000 and 11,000 Da, respectively. Biochemical characterization of these proteins has been persued through polyclonal antisera, which were derived to synthetic peptides. Using these sera for Western blotting analyses the recombinant AT464 and AT744 proteins could be detected as secreted products from transfected COS cells and from baculovirus-infected Sf9 cells. Similarly the native proteins could be detected in the supernatants of activated human peripheral blood T cells. The recombinant and the T cell-secreted AT464 and AT744 proteins appear to be identical as judged by their mobility by SDS-PAGE and by their reactivity with the rabbit polyclonal antisera.

[Hemodynamic differences do not exist in patients with adult respiratory syndrome with or without infection]

BACKGROUND

To verify whether patients with adult respiratory distress syndrome (ARDS), associated to sepsis or not, may be differentiated according to the values of the hemodynamic variables.

METHODS

Thirty-two consecutive patients with ARDS admitted to an intensive care unit over a period of 32 months were prospectively studied. In 18 patients ARDS was associated to sepsis. The value of the hemodynamic variables were compared between both groups of patients (18 with sepsis and 14 without) within the first 24 hours of diagnosis of the syndrome.

RESULTS

Mortality of patients with ARDS associated with sepsis was greater than in those without sepsis (78% vs 57%). In general both groups of patients with ARDS presented similar values of pulmonary hypertension (28 +/- 6 and 25 +/- 4 mmHg) with elevated pulmonary vascular resistance, and with an above normal cardiac index and ventricular function parameters. No significant differences were found in hemodynamic values, ventricular function and oxygen transport among patients with ARDS, with or without sepsis, or among survival or death in each group, or those considered in general.

CONCLUSIONS

This study demonstrated that patients with the septic adult respiratory distress syndrome (ARDS) have the same hemodynamic changes as those observed in patients with ARDS without sepsis. This absence of differences may be explained by the presence of mechanisms common in sepsis and ARDS.

A novel mitogen-inducible gene product related to p50/p105-NF-kappa B participates in transactivation through a kappa B site

A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.

Cloning of a mitogen-inducible gene encoding a kappa B DNA-binding protein with homology to the rel oncogene and to cell-cycle motifs

We have cloned and characterized a mitogen-inducible gene isolated from human T cells that predicts a protein of 968 amino acids. The amino-terminal domain has regions homologous to the oncogene rel and to the developmentally important gene dorsal of Drosophila. The carboxy-terminal domain contains repeat structures found in a variety of proteins that are involved in cell-cycle control of yeast and in tissue differentiation in Drosophila and Ceanorhabditis elegans, as well as in the putative human oncogene bcl-3 and in the ankyrin protein. A truncated form of the product of this gene translated in vitro is a DNA-binding protein which interacts specifically with the kappa B binding site found in many inducible genes, including the enhancer in human immunodeficiency virus. This gene is yet another in a growing list of important regulatory molecules whose expression is transcriptionally induced upon cellular activation.

Age-related changes in the subcortical afferents to the medial frontal cortex in mice: a WGA-HRP study

The subcortical afferent projections to the mediodorsal part of the frontal cortex were studied both qualitatively and quantitatively in young (3 months), adult (12 months) and aged (22 months) Balb/c mice by means of the retrograde transport of wheat germ agglutinine-horseradish peroxidase (WGA-HRP). A progressive decrease in the number of afferents was observed during aging with a differential pattern of reduction as a function of the subcortical structures. In adult mice a large reduction of afferents occurs in the diagonal band of Broca, the posterior thalamic nucleus, the zona incerta, the lateral hypothalamic area, the nuclei of amygdaloid complex, the posterior hypothalamic nucleus, the reticular pontine nucleus, the dorsal and medial raphe nuclei and the dorsal tegmental nucleus. In aged animals, only the anteromedial and mediodorsal thalamic nuclei, as well as the locus coeruleus appear to be clearly affected.

Kinetic lability of zinc bound to metallothionein in Ehrlich cells

Ehrlich ascites-tumour cells normally contain a large concentration of Zn-metallothionein. When cells are placed in culture media, containing or pretreated with the metal-ion-chelating resin Chelex-100, they stop growing, remain viable and lose zinc specifically from the metallothionein (MT) pool. The kinetics of loss of zinc are first-order and are very rapid, having a rate constant of greater than or equal to 0.6 h-1. MT protein labelled with 35S is biodegraded with a rate constant of 0.07-0.014 h-1 in control cells, 0.08 h-1 in cells exposed to the zinc-deficient medium and 0.12-0.18 h-1 in cells treated directly with Chelex. Over the 6 h period in which zinc is totally lost from Zn-MT there is relatively little decrease in MT-like protein as measured by cadmium-binding to the 10,000-Mr protein fraction. Other pools of zinc and 35S-labelled protein turn over more slowly. There is no loss of zinc from rat liver Zn-MT that is dialysed against Chelex to model the possible reaction of the resin with Ehrlich-cell Zn-MT. However, Chelex does compete slowly for MT-bound zinc when resin and MT are directly mixed. Analysis of the known and possible pathways of zinc metabolism in cells in relationship to these rate constants shows that biodegradation of MT protein cannot account for the rate of loss of zinc from Zn-MT.

The differential ascending projections from the anterior, central and posterior regions of the lateral hypothalamic area: an autoradiographic study

The ascending efferent projections of the neurons of the anterior (LHAa), central (LHAc) and posterior (LHAp) parts of the lateral hypothalamic area (LHA) have been studied using an autoradiographic analysis of the anterograde axonal transport after local injection of tritiated amino acids. Our results show that LHA regions have common projections particularly to the thalamus and to the hypothalamus. They also demonstrate the existence of differential projections: i.e. an anteroposterior gradient of projection sites according to anterior, central and posterior localisation of the LHA neurons. The LHAa neuronal projections terminate in the lateral septal area; the LHAc projections innervate the frontal cortex while LHAp neurons send their projections to the olfactory bulb and innervate both the cerebral cortex and the hippocampus. Only the LHAp neurons project measurably to the globus pallidus, the caudate putamen and the nucleus accumbens.

The differential descending projections from the anterior, central and posterior regions of the lateral hypothalamic area: an autoradiographic study

The descending projection sites of the anterior, central (or tuberal) and posterior regions of the lateral hypothalamic area were studied by anterograde axonal transport after local injection of tritiated amino acids. The results show that the neurons of the anterior regions project to the lateral mammillary nucleus, the ventral tegmental area, the midbrain central gray and the anterior parts of the dorsal raphe nucleus. The neurons of the central region project in the same structures and extend a projection into the dorsal tegmentum at the level of the pontine central gray, the midbrain and pontine reticular nuclei. In the ventral tegmentum region, the substantia nigra pars compacta, the interpeduncular nucleus and the anterior group of raphe nuclei were also found to be labelled. The neurons of the posterior region of the lateral hypothalamic area extend a projection to the level of the prepositus hypoglossi nucleus and to the nucleus of solitary tract. In the ventral tegmentum they project at the level of posterior group of the raphe nuclei and the inferior olivary complex.

Cadmium-zinc interactions in the Ehrlich cell: metallothionein and other sites

Zinc and Cadmium metabolism in cultured Ehrlich cells has been studied. Under conditions of restriction of extracellular zinc by EDTA or chelex, zinc in basal Zn-metallothionein (Mt) is transferred from metallothionein to other sites with a rate constant of 0.35 hr-1. Current studies indicate that the rate constant for biodegradation of Mt protein is 0.07-0.11 hr-1, implying that Zn leaves the protein faster than it is biodegraded. After a 30 minute exposure of cells to 17 ng atoms Cd/mg cell protein, Cd initially displaces Zn from Mt and binds to high molecular weight species. Cell proliferation is markedly slowed, although the cells remain viable. Over time Cd shifts into newly synthesized Mt. This protein is made with an apparent rate constant four times that for basal Zn-Mt. The product contains equal amounts of Cd and Zn. However, cell proliferation is not restored for many hours after Cd is sequestered in Mt.

Computerized system in intensive care medicine

A complete understanding of the computer's capabilities and an exact identification and definition of the ICU problems/needs are essential for the complete control of patient records and the full utilization of the computer as a clinical tool.

Single unit activity in the nucleus of the basal optic root (nBOR) during optokinetic, vestibular and visuo-vestibular stimulations in the alert pigeon (Columbia livia)

Extracellular recordings were performed in the nucleus of the basal optic root (nBOR) of alert pigeons during optokinetic nystagmus (OKN), vestibulo-ocular reflex (VOR) and combined visuo-vestibular stimulation. Cell identification was assessed either by histological control or by electrophysiological testing (antidromic response to vestibulo-cerebellar or oculomotor complex stimulation). 1) OKN was induced in 8 directions by a binocular stimulation. During the fast phase of OKN, optokinetic after nystagmus (OKAN) or reversed OKAN, most cells showed an inhibition which varied in magnitude independent of the direction of stimulation. A few cells however showed a phasic discharge for some OKN directions. 2) During the slow phase of OKN induced by a binocular stimulation, cells displayed either a tonic activation or a more or less strong inhibition according to the direction of the OKN. Cells were classified in 4 groups, according to their degree of directional specificity. The best OKN direction (slow phase) for maximal cell activation was upwards and naso-upwards, and next to best, naso-temporal and downwards. Maximal cell inhibition occurred during downward, and for some cells during upward, directions. 3) During OKN induced by stimulating the eye contralateral to the recorded nBOR, cell responses resembled those obtained during binocular stimulation, but, during ipsilaterally induced OKN, the cells lost their directional specificity. As a result of binocular integration, neuronal activation seems to originate from contralateral input whereas cell inhibition would mainly come from ipsilateral input. 4) During sinusoidal optokinetic stimulation induced in the temporo downward-naso upward axis, cells showed a more or less marked modulation (according to their directional selectivity) that was closely in phase with the stimulation velocity, and therefore probably with retinal slip. 5) nBOR cells appeared generally unaffected during both the slow phase and the fast phase of the VOR. However, some cells showed a slight but irregular modulation which might imply a weak vestibular input. During visuo-vestibular stimulation, the response resembled that obtained with sinusoidal optokinetic stimulation but the fast phase inhibition was often strengthened in the downwards direction (fast phase).

Efferent projections of the visual Wulst upon the nucleus of the basal optic root in the pigeon

Efferent projections of the visual Wulst upon the nucleus of the basal optic root (nBOR) were investigated using various neuroanatomical approaches: optical and EM orthograde degeneration methods (following visual Wulst ablation), radioautographic and HRP techniques (following injection of various tracers within the visual Wulst). The radioautographic and electron microscope degeneration experiments clearly demonstrated a visual Wulst projection upon the ipsilateral nBORl and the lateral portions of nBORd and nBORp. The pigeon's hyperstriato-nBOR projection is compared to a similar descending visual cortico-accessory optic pathway in mammals and its possible role in the control of oculomotor function is discussed.

Optokinetic nystagmus in the pigeon (Columba livia). III. Role of the nucleus ectomamillaris (nEM): interactions in the accessory optic system (AOS)

The accessory optic system (AOS) in birds is composed of two structures: the nucleus Superficialis Synencephali (nSS), essential for the production of an optokinetic nystagmus (OKN) in the temporo-nasal direction (slow phase) for the eye contralateral to the nucleus, and the nucleus Ectomamillaris (nEM), or nucleus of the basal optic root (nBOR). The objectives of the present work were: (1) to study the importance of the nEM for the horizontal OKN, (2) to study the interactions between the nSS and the nEM. Experiments were realized by combining different kinds of lesion. (1) Results show that the nEM is essential for the production of an OKN in the naso-temporal direction (direction of the slow-phase), but it also participates in the temporo-nasal response. (2) After bilateral lesion of the nEM or the nSS, only a residual nystagmic response remains. (3) Synergic effects exist between (I) the homolateral nEM and nSS, or between the systems related to them; we call this relation "homolateral synergy", (II) a nEM and the contralateral nSS (or systems related to these nuclei). The synergic effect exerted by one nEM upon the contralateral nSS appears to be stronger than the reciprocal effect. (4) The effects obtained after combined lesions, either homolateral (nEM and nSS on the same side) or heterolateral (nEM and nSS on opposite sides) confirm the previous results and show that heterolateral interactions are stronger than homolateral interactions. (5) For all the lesions studied, the results obtained from binocular stimulation are compatible with a model of convergence of monocular inputs. The role of the nuclei of the AOS in birds is discussed in terms of existing anatomical and physiological data.

Optokinetic nystagmus in the pigeon (Columba livia). II. Role of the pretectal nucleus of the accessory optic system (AOS)

In birds, the accessory optic system (AOS) includes two nuclei: the nucleus ectomamillaris (nEM) and the pretectal nucleus superficialis synencephali (nSS). The role of the nSS in the production of a horizontal optokinetic nystagmus (OKN) was studied in the pigeon, by comparing the OKN before and after a unilateral lesion of this nucleus. The lesions were performed either by electrolysis or by local application of kainic acid (KA); the KA lesions gave more stable modifications of the OKN than the electrolytic lesions. A quantitative analysis of the slow-phase velocity (V) of the OKN was carried out on the animals receiving KA lesions. Lesion of the nSS provokes the almost total disappearance of the OKN for stimulation of the contralateral eye in the temporo-nasal direction, and a reduction of the OKN for stimulation in the naso-temporal direction. Thus, the nSS is essential for the production of the OKN in the temporo-nasal direction, but it also participates in the production of the OKN in the naso-temporal direction (slow-phase direction). The same lesion produces a large increase of the OKN (V) when the ipsilateral eye is stimulated in the temporo-nasal direction, and a smaller increase following stimulation in the naso-temporal direction. These increases suggest some kind of inhibitory (or disfacilitatory) interactions between the nSS (or the associated system) on one side, and the contralateral optokinetic centers. The lesion of one nSS does not provoke a deficit when the stimulation is binocular. This result probably reflects the combined effect of both monocular inputs. After a pretectal KA injection, a spontaneous nystagmus of the contralateral eye, in the naso-temporal direction, can be seen for several hours. The mechanism is still unknown, but it might be related to a reverse optokinetic after nystagmus (R-OKAN). The anatomical and physiological data so far available consistently support the hypothesis of a functional equivalence between the nSS in birds and the nucleus of the optic tract in mammals.

[Single unit activity in the nucleus ectomamillaris (nem) during optokinetic nystagmus, in the pigeon]

Extra-cellular recordings of single units were obtained in the nucleus ectomamillaris (nEM) in waking Pigeons, during optokinetic nystagmus (OKN). OKN was obtained for 8 directions of stimulation (horizontal, vertical and oblique) in monocular and binocular vision. For half of the units the responses were synchronized, showing activation during the slow-phase and inhibition during the fast phase of the OKN. This response pattern was more common for the horizontal OKN, both in the Nasal to Temporal (N-T) and in the Temporal-to-Nasal (T-N) directions. With contralateral stimulations, most cells showed directional selective responses for upwards and backwards directions, the activity being inhibited for the other directions. Some units showed a less marked directional selectivity or were unaffected by the stimulations. Ipsilateral stimulations provoked no directional selectivity, but rather a reduction of the firing level. With binocular stimulation, responses were very close to those obtained with contralateral stimulation, with an increase of the directional selectivity. The nEM seems to be involved in the control of OKN, specially for the N-T and upwards directions, and less significantly for the T-N direction.

Computerized information system for ICU patient management

To solve the problem of data management, a digital computer was introduced in this ICU in 1977. Data are manually entered at the bedside alpha-numeric keyboards; two beds are directly connected to the computer. The system was especially designed to work in the 11-bed ICU; its functions are: (1) admission, discharge, and transfer data of patients; (2) management of doctors' and nurses' notes in a free text form; (3) management of the problem-oriented record; (4) management of physical and bio chemical variables, medical disorders, and fluid balance; and (5) diagnostic and therapeutic decision-making. Since 1977, the authors have computerized over 2600 patients and now conclude: (1) data management and communication have improved, thus, allowing nurses more time for direct patient care; (2) teaching of the residents and nurses has been facilitated and minimizes disparities from their diverse experience; (3) it has contributed to the development of protocols for many of the procedures; and (4) it has led to a more systematic approach to patient care. The assistance of a professional computer programmer and continuous maintenance of the software are essential.

[Horizontal optokinetic nystagmus in the pigeon: role of accessory optical system]

Some characteristics of the horizontal optokinetic nystagmus (OKN) have been studied in the pigeon using monocular and binocular stimulations. The OKN is asymmetrical, temporal to nasal stimulation eliciting a larger response than a nasal to temporal one. The role of the accessory optic system (AOS) was studied by means of unilateral or bilateral lesions of the primary relays, nuclei ectomamillaris (nEM) and superficialis synencephali (nSS). Results show the existence of a synergy between nEM and nSS on the same side and between nEM and nSS on opposite sides, whereas each nucleus has an inhibitory effect upon its contralateral homologue. Some evidence was obtained which suggests the existence of an ipsilateral retinal projection to the nEM.