Integrating mental health services within primary care. A Canadian program

The increasingly prominent role of the family physician in delivering mental health care can be enhanced if productive and collaborative relationships can be established with local mental health services. This paper describes a Canadian program that has achieved this by bringing mental health counselors and psychiatrists into the offices of 87 family physicians in 35 practices in a community in Southern Ontario. The paper describes the program, the activities of counselors and psychiatrists within the practices, and the administrative structures set up to coordinate these activities. Data is presented from the evaluation of the first year of the program's operation (13 practices and 45 family physicians) during which time 3085 referrals were received. The program made mental health care more available and accessible, increased continuity of care, provided additional support for the family physician, offered new opportunities for continuing education, and led to a reduced and more efficient use of other mental health services. The components of the program can be adapted to most communities.     

Chemical synthesis and physiological activity of sulfonium analogues of platelet activating factor

Phosphatidylsulfocholine (PSC), the sulfonium analogue of phosphatidylcholine (PC), occurs naturally in some diatoms. The replacement of the −N⁺(CH₃)₃ group by a −S⁺(CH₃)₂ results in an increase in the polar head group size in PSC relative to that of PC, consistent with the observed increase in permeability of PSC bilayers towards urea. It was of interest to see whether replacement of the −N⁺(CH₃)₃ group in platelet activating factor (PAF) by an −S⁺(CH₃)₂ group leads to any change in platelet aggregation or other physiological activity. Synthesis of the sulfonium analogue of PAF was carried out by suitable modifications of known procedures. The PAF-sulfonium analogue was found to have almost the same platelet aggregating activity as PAF itself, in the concentration range 1–20 μM, but a much lower activity in the range 0.01–1 μM. The analogue had little or no effect on the platelet aggregation activity of PAF when added in the concentration range 0.01–1 μM and had about half the hypotensive activity of PAF towards hypertensive CDF male rats. The sulfonium analogue, however, was much more cytotoxic to HL-60 cells than PAF itself, in the concentration range 0–15 μM; replacement of the acetate group by a benzyl group increased the cytotoxicity to the level of that of the methoxy analogue of PAF. Thus, replacement of the −N⁺(CH₃)₃ group by a −S⁺(CH₃)₂ group in the polar head group region of PAF results in a relatively small change in its platelet aggregation activity and a decrease in its hypotensive activity, but greatly increases its antitumor activity. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 8–12, 1989.     

Sterols,aliphatic hydrocarbons,and fatty acids of a nonphotosynthetic diatom,Nitzschia alba

The unsaponifiable lipids and total fatty acids of a nonphotosynthetic diatom,Nitzschia alba, have been examined. The major fatty acids were found to be 14∶0, 16∶0, 18∶1, and 20∶5; small amounts of 15∶0, 16∶1, 18∶0, 18∶2, 18∶3, and 20∶4 acids also were present. The unsaponifiable lipids consisted mostly of sterols, with only traces (<0.1%) of hydrocarbons (chiefly C₁₆, C₁₈, and C₂₈ normal olefins). The sterols contained brassicasterol (major) and clionasterol (minor), as well as traces of an unidentified sterol; clionasterol was present only in glycosidically bound form.     

The dietary regulation of acyltransferase and desaturase activities in microsomal membranes of rat liver

Dietary manipulation produces marked alterations in desaturase activities of rat liver microsomes with no concomitant changes in acyltransferase activities. Desaturation of stearoyl-CoA (Δ9-desaturase), linoleoyl-CoA (Δ6-desaturase), eicosatrienoyl-CoA (Δ5-desaturase) and eicosatrienoyl-phosphatidylcholine (Δ5-desaturase) was elevated in animals fed a corn oil diet and lowered in those fed a coconut oil diet compared to control animals. The Δ5-desaturase activities were also lowered in starved animals and elevated in starved animals refed a fat-free diet. However, no changes in acyl-CoA:1-acylsn-glycero-3-phosphocholine acyltransferase activity were observed in the membranes of animals maintained on any of the dietary regimens studied. These observations suggest that the desaturases of rat liver microsomes are regulated independently of the acyltransferases and that desaturation of eicosatrienoyl-phosphatidylcholine is regulated at the level of the desaturase itself and not by availability of the phospholipid substrate.     

Acyl-acyl carrier protein as substrate of the acyltransferase of rat liver microsomes

Acyl-acyl carrier protein (acyl-ACP) can serve as well as acyl-CoA as substrate of the 1-acyl-sn-glycero-3-phosphocholine (1-acyl-GPC) acyltransferase of rat-liver microsomes. The product of the acylation with either thioester substrate is predominantly phosphatidylcholine (PC) (92–95%). The acyl-group transferred from either myristoyl-CoA or myristoyl-ACP is located at the C-2 position of the phospholipid (PL). The apparent Km values for the myristoyl-CoA and myristoyl-ACP were 46 μM and 63 μM, and the corresponding apparent Vmax values were 1.0 and 1.6 nmol/min/mg. The rate of acylation with the acyl-ACP was unaffected by the addition of free CoA-SH. These data suggest that acyl-CoA and acyl-ACP are transferred to 1-acyl-GPC by the same or similar enzyme systems.     

Speech enhancement based on a sinusoidal model

Sinusoidal modeling is a new procedure for representing the speech signal. In this approach, the signal is divided into overlapping segments, the Fourier transform computed for each segment, and a set of desired spectral peaks is identified. The speech is then resynthesized using sinusoids that have the frequency, amplitude, and phase of the selected peaks, with the remaining spectral information being discarded. Using a limited number of sinusoids to reproduce speech in a background of multi-talker speech babble results in a speech signal that has an improved signal-to-noise ratio and enhanced spectral contrast. The more intense spectral components, assumed to be primarily the desired speech, are reproduced, whereas the less intense components, assumed to be primarily background noise, are not. To test the effectiveness of this processing approach as a noise suppression technique, both consonant recognition and perceived speech intelligibility were determined in quiet and in noise for a group of subjects with normal hearing as the number of sinusoids used to represent isolated speech tokens was varied. The results show that reducing the number of sinusoids used to represent the speech causes reduced consonant recognition and perceived intelligibility both in quiet and in noise, and suggests that similar results would be expected for listeners with hearing impairments.     

"High-load" polyethylene glycol-polystyrene (PEG-PS) graft supports for solid-phase synthesis

In the rat dorsal hippocampus and dorsal raphe nucleus, the microiontophoretic application of ergotamine and 5-HT suppressed the firing activity of CA3 pyramidal neurons and 5-HT neurons, an effect antagonized by selective 5-HT1A receptor antagonists. Co-application of ergotamine prevented the inhibitory action of 5-HT on the firing activity of CA3 pyramidal neurons but not of 5-HT neurons, indicating that ergotamine acted as a partial 5-HT1A receptor agonist in the dorsal hippocampus and as a full agonist at 5-HT1A autoreceptors. Ergotamine decreased, in a concentration-dependent manner, the electrically evoked release of [3H]5-HT in preloaded rat and guinea pig hypothalamus slices; this effect was prevented by the nonselective 5-HT receptor antagonist methiothepin but not by the selective 5-HT1B/1D receptor antagonist GR 127935 or the alpha 2-adrenoceptor antagonist idazoxan. Although body temperature in humans remained unchanged following inhaled ergotamine, in the rat, subcutaneously injected ergotamine produced a hypothermia that was prevented by a pretreatment with the 5-HT1A/1B receptor/beta-adrenoceptor antagonist pindolol. Finally in humans, ergotamine did not alter prolactin or adrenocorticotropic hormone levels, but increased growth hormone level, which was prevented by pindolol. Cortisol level was increased in humans by ergotamine, but this enhancement was unaltered by pindolol. In conclusion, the present results suggest that ergotamine acted in the rat brain as a 5-HT1A receptor agonist and as an agonist of terminal 5-HT autoreceptor of a yet undefined subtype. In humans, ergotamine also displayed some 5-HT1A receptor activity but, probably because of lack of receptor selectivity, it did not present the same profile as other 5-HT1A receptor agonists.     

Refocusing the lens: epidemiologic transition theory, mortality differentials, and the AIDS pandemic

The epidemiologic transition theory presented first by Omran [Omram. A. R. (1971) The epidemiologic transition: a theory of the epidemiology of population change, Mildbank Quarterly 49(4), 509-538] was designed to explain global trends in the dynamic relationship between epidemiological phenomena and demographic change. This paper argues that universalizing this theory only partially serves to explain mortality declines over the last century and eclipses key epidemiologic differences between population subgroups based on socioeconomic status, race, and sex. This paper examines morbidity and mortality differentials between population subgroups and demonstrates important inconsistencies with the optimistic trends implied by the epidemiologic transition theory, an argument further developed using the HIV/AIDS pandemic as a case study. The paper argues that these differences should be brought from margins to center to present a more complex and comprehensive picture of how population subgroups experience epidemiologic transitions differently.     

Conceptual sorting and personality adjustment in children.

24 relatively well adjusted and 24 relatively poorly adjusted children, selected from 150 normal 6th-grade children, were compared on the Gelb-Goldstein-Weigl-Scheerer Object Sorting Test. Poorly adjusted children made significantly more inadequate sortings than well adjusted children, confirming the prediction of this study. High and average intelligence children were more adequate in their object sortings than low intelligence children. Relatively poorly adjusted children, because of lack of appropriate categories, may not be as able to reduce environmental complexity and assign meaning to events as relatively well adjusted children. High and average intelligence, at this age level, contributes to the ability to abstract and use shared properties as a grouping principle. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A time-domain digital cochlear model

The author presents a digital time-domain model of the human cochlea designed to represent normal auditory functioning and to allow for degradation related to auditory impairment. The model consists of the middle ear, the mechanical motion of the cochlea, and the neural transduction of the inner hair cells. The traveling waves on the cochlear partition are represented by a cascade of digital filter sections, and the cochlear micromechanics are represented by a second filter that further sharpens the excitation to the inner hair cells. The neural firing rate is determined by the sum of the outputs of multiple fibers attached to each inner hair cell, with the fiber neurons having firing characteristics representative of low- and high-spontaneous-rate fibers. The signal processing cochlear model incorporates dynamic-range compression by adjusting the Q of each cochlear filter section and second filter in response to the second-filter velocity and the averaged neural firing rate. Examples of the model response to impulse and tone-burst stimuli and to synthetic speech are presented