Clinical features and predictive markers of disease progression in cynomolgus monkeys experimentally infected with simian immunodeficiency virus

OBJECTIVE

To study the pathogenicity of simian immunodeficiency virus (SIVsm) in cynomolgus monkeys in order to establish an animal model for human AIDS.

METHODS

Thirty-three cynomolgus monkeys were monitored for more than 2 years following experimental infection with SIVsm.

RESULTS

All the macaques became SIV-infected, as demonstrated by virus recovery from peripheral blood lymphocytes and by the appearance of viral antibodies. SIVsm was found to be pathogenic, killing 29 out of the 33 monkeys (88%) within 26 months. Clinically, infected monkeys developed lymphadenopathy, splenomegaly, diarrhoea, weight loss, neurological symptoms and a remarkably high incidence (39%) of malignant lymphomas. All lymphomas were high-grade malignant and of B-cell origin. Disease progression was associated with low CD4+ lymphocyte count, involution of initially hyperplastic follicular B-cell areas in lymph nodes, reappearance of viral antigen in serum, loss of anti-Gag antibodies and development of systemic giant cell disease in 55% of the monkeys.

CONCLUSIONS

There are many similarities between SIVsm-induced AIDS in cynomolgus monkeys and human AIDS with regard to clinical, virological, immunological and pathological manifestations.

A formalin inactivated whole SIVmac vaccine in Ribi adjuvant protects against homologous and heterologous SIV challenge

Eight monkeys were immunized at 0, 4, 9, and 18 weeks with a total of 2 mg of formalin inactivated SIVmac vaccine with Ribi adjuvant. Two weeks after the last booster four immunized monkeys and two controls were challenged with 10 MID50 of live homologous virus SIVmac, and the remaining four vaccinated animals along with two controls were challenged with the heterologous SIVsm strain. All eight vaccinated monkeys resisted the virus challenge, whereas all controls became infected. Three months after the first challenge the monkeys were rechallenged with the same virus strain, without further boosting. Two of four vaccinated monkeys were still resistant to the homologous SIV strain, and three of four monkeys were resistant to the heterologous SIVsm strain. This study demonstrates vaccine induced cross-protection between SIV strains.

Circadian variation in human cerebrospinal fluid production measured by magnetic resonance imaging

Recent advances in magnetic resonance imaging have made it possible to visualize and quantify flow of cerebrospinal fluid (CSF) in the brain. The net flow of CSF through the cerebral aqueduct was used to measure CSF production in six normal volunteers at different times during a 24-h period. CSF production varied greatly both intra- and interindividually. The average CSF production in each time interval showed a clear tendency to circadian variation, with a minimum production 30% of maximum values (12 +/- 7 ml/h) approximately 1800 h and a nightly peak production approximately 0200 h of 42 +/- 2 ml/h. The total CSF production during the whole 24-h period, calculated as an average of all measurements, was 650 ml for the whole group and 630 ml for repeated measurements in each time interval in one of the volunteers.

Simultaneous and continuous measurement of choroid plexus blood flow and cerebrospinal fluid production: effects of vasoactive intestinal polypeptide

Using laser-Doppler flowmetry during ventriculocisternal perfusion with inulin-[14C]carboxylic acid, choroid plexus blood flow (CPBF) and CSF production were measured simultaneously in rats during periods of 3 h. Blood flow and CSF production decreased only slightly during control experiments. The effect of vasoactive intestinal polypeptide (VIP) was studied at different concentrations of the peptide given either intraventricularly or intravenously. Intraventricular administration of VIP (10(-9) or 10(-7) M) resulted in a decrease in CSF production of up to 30%, while CPBF increased by 20%, also demonstrating that CSF production and blood flow are not directly coupled in the choroid plexus. When infused intravenously, VIP (10 or 100 pmol/kg/min) increased CPBF, an effect partly antagonized at higher concentrations owing to a VIP-induced systemic hypotension. No effect of VIP on CSF production could be seen with intravenous administration.

Epithelial cells purified from choroid plexus have receptors for vasoactive intestinal polypeptide

Using the choroid plexus from pig a method has been developed to purify the epithelial cells from the underlying vascularized connective tissue stroma. An epithelial cell fraction was obtained that showed a purity of at least 95%, as determined by light microscopic analysis. The epithelial cells were investigated for the presence of binding sites for the neurotransmitter peptide, vasoactive intestinal polypeptide (VIP). Suspensions of epithelial cells were found to have high affinity binding sites for 125I-labelled VIP, with maximum binding obtained after 30 min incubation at 20 degrees C with a concentration of 50 micrograms cell protein per sample. Competition experiments with displacement of [125I]VIP binding by increasing concentrations of unlabeled VIP indicated the presence of a single class of binding sites with a Kd of 3 nM and a binding capacity of 970 pmol/g cell protein. Cross-linking of [125I]VIP to epithelial cells with disuccinimido dithiobis (propionate) (DSP), followed by SDS-polyacrylamide gel electrophoresis, demonstrated binding to a single 55 kD protein. The receptor was highly specific for VIP as binding was only inhibited in the presence of high concentrations of the related peptides helodermin, growth hormone-releasing factor, secretin, and peptide histidine isoleucine. This is the first demonstration of VIP-binding to choroid plexus epithelial cells.

The neuropeptides vasoactive intestinal polypeptide, peptide histidine isoleucine and neuropeptide Y modulate [3H]noradrenaline release from sympathetic nerves in the choroid plexus

The neurotransmitter peptides vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI) and neuropeptide Y (NPY) are located in nerve fibers supplying the pig choroid plexus, which receives an abundant sympathetic innervation. We characterized the release of [3H]noradrenaline ([3H]NA) from this tissue elicited by electrical field stimulation and studied the effects of the above-mentioned peptides on this release. The release of [3H]NA was found to be almost exclusively of neurogenic origin, despite there being a marked non-neuronal uptake of [3H]NA into the epithelium of the choroid plexus. NPY significantly decreased the release of [3H]NA by approximately 10% while VIP and PHI enhanced release by up to 25 and 35%, respectively, indicating a possible synergistic role of the two latter peptides and NA in the choroid plexus.

Thyroxine transport from blood to brain via transthyretin synthesis in choroid plexus

The transport of thyroxine from the bloodstream to the brain and the synthesis and secretion of transthyretin (formerly called prealbumin) were studied in rats and in sheep choroid plexus perfused in vitro. Rat choroid plexus contained 4.4 micrograms and rat liver 0.39 micrograms transthyretin mRNA per gram wet tissue. The specific radioactivity of transthyretin isolated from cerebrospinal fluid of rats 60 min after intravenous injection of [14C]leucine was greater than 50 times that of transthyretin from serum. After adding [14C]leucine to the perfusion medium of an in vitro perfused sheep choroid plexus, highly radioactive transthyretin was isolated from freshly secreted cerebrospinal fluid collected from the exposed choroid plexus surface. Secretion of newly synthesized transthyretin into the perfusion medium could not be demonstrated. After intravenous injection of [125I]-thyroxine into rats, a maximum in the curve of radioactivity in tissue plotted against time after injection was observed first for choroid plexus, thereafter for cerebrospinal fluid, and still later for cortex and striatum. Based on the obtained data, a hypothesis is derived for the mechanism of the transport of thyroid hormones from the bloodstream to the brain involving transthyretin synthesized in choroid plexus and secreted into the cerebrospinal fluid.

Studies of multilayers and thin-foil x-ray mirrors using a soft x-ray diffractometer

A versatile x-ray diffractometer is described in detail. Two applications to the study of x-ray optical elements are presented. The first is a Bragg reflection study of state-of-the-art multilayers deposited both on conventional Si-wafer substrates and on superpolished substrates such as fused quartz and electroless nickel. These data are compared to data previously obtained at FeKα. The second study is a reflectivity and scattering study of various thin-foil x-ray reflectors proposed for up-coming x-ray satellite missions. All the data have been obtained at MgKα = 1.2536 keV.

Distribution of peptidergic nerves in the choroid plexus, focusing on coexistence of neuropeptide Y, vasoactive intestinal polypeptide and peptide histidine isoleucine

Choroid plexus from rat, guinea-pig, rabbit and pig was investigated by light-microscopic immunohistochemistry and by radioimmunoassay for the presence of neuropeptides. A moderately dense supply of nerve fibers containing neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), respectively, was found around blood vessels and in close relation to the secretory epithelium in both pig and rabbit, while lower densities of nerve fibers were found in rat and guinea-pig. Peptide concentrations ranged from 10-40 pmolequivalents/g (pmoleqv/g) for NPY and 0.5-6 pmoleqv/g for VIP in all four species. Peptide histidine isoleucine (PHI) immunoreactive nerve fibers were present in pig choroid plexus at a lower density than NPY and VIP but with a similar distribution. Low concentrations of substance P (0.3-3 pmoleqv/g) and calcitonin gene-related peptide (0.1-3 pmoleqv/g) were found to a varying degree in choroid plexus tissue from the different species, while immunohistochemical investigation was unable to detect any immunoreactive nerve fibers. NPY was often found to coexist with VIP and PHI in pig choroid plexus, while a lesser amount of nerve fibers showed coexistence of NPY and the noradrenaline synthetizing enzyme, dopamine-beta-hydroxylase. Surgical sympathetic denervation by excision of the superior cervical ganglion in the rabbit abolished NPY-containing nerve fibers, as revealed by immunohistochemistry, but only decreased NPY levels by one third, which may be due to different identity of the peptide being detected by the two techniques. It is concluded that NPY-containing nerve fibers have a dual origin in the choroid plexus and coexist with either noradrenaline or VIP/PHI.

Silicate pneumoconiosis in camels (Camelus dromedarius L.)

In a random screening of camel diseases in Somalia dust-laden macrophages in lungs and/or bronchial lymph nodes were discovered in 94 of 134 animals. In 44 cases the dust-laden macrophages occurred in a number of small or large aggregates. There was a significant positive correlation between dust-laden macrophage aggregates in the lungs and pulmonary fibrosis not related to other chronic lung diseases, such as echinococcosis and chronic pneumonia. Six cases showed a cellular reaction and hyalinized nodules of the classic silicotic type. Energy dispersive X-ray analysis of the dust particles revealed presence of silica, aluminium, potassium and iron in that order. The possible clinical significance as well as the comparative pathology of the observations is discussed.

Immunohistological localisation of rinderpest virus in formalin-fixed, paraffin-embedded tissues from experimentally infected cattle

Six Freesian steers were subcutaneously inoculated with the virulent rinderpest virus strain Kabete "0" and sacrificed at the height of fever. Sections of formalin-fixed, paraffin-embedded tissues were stained according to the peroxidase anti-peroxidase (PAP) technique. Labelling of viral antigen, both in the cytoplasm and in the nuclei of infected cells, was observed in the epithelial cells of the upper and lower alimentary tract and in lymphoid organs, i.e. spleen, lymph nodes, pharyngeal tonsils, Peyer's patches and thymus. Electron microscopy studies confirmed the results.

Effect of 5-hydroxytryptamine on the rate of cerebrospinal fluid production in rabbit

Infusion of 5-hydroxytryptamine in mock cerebrospinal fluid of rabbits lowered cerebrospinal fluid production dose-dependently by nearly 30%. The effect was amplified in the presence of the monoamine oxidase inhibitor, nialamide. The 5-hydroxytryptamine-induced inhibition was partly counteracted by ketanserin, and further addition of practolol completely blocked the reduction in cerebrospinal fluid formation, suggesting that both 5-hydroxytryptamine receptors and beta 1-adrenergic receptors were involved in the response mediated by both the secretory epithelium and the vascular bed of the plexus.

Histaminergic cells in the choroid plexus of rat

The choroid plexus of the rat was examined immunocytochemically using both an antibody directed towards a histamine thyroglobulin conjugate as well as to histidine decarboxylase. Histamine- as well as histidine decarboxylase-immunoreactive cells were found within or in the vicinity of the plexus epithelium, with processes extending to the neighbouring epithelial cells or surrounding tissue, suggesting a specific function for histamine on the choroid plexus.

Pneumonia and acute pancreatitis most probably caused by a Legionella longbeachae infection

Legionella longbeachae was first described and characterized in 1981. We report the first probable case of L. longbeachae infection in Sweden. A previously healthy, 50-year-old greenhouse repairman fell ill with severe pneumonia and acute pancreatitis. The L. longbeachae type 1 IgG titer (indirect immunofluorescence) was 256 and decreased significantly with erythromycin treatment. Attempts to isolate the microorganism from the environment failed. Sera from the patient's colleagues and from blood donors all had antibody titers of less than 32.

Growth hormone responses to clonidine and GRF in spontaneously hypertensive rats: neuroendocrine evidence for an enhanced responsiveness of brain alpha 2-adrenoceptors in genetical hypertension

Clonidine induces growth hormone (GH) release in rat. According to previous investigations this effect is mediated by postsynaptic alpha 2-adrenoceptors in the hypothalamus exerting a stimulatory influence on the recently discovered GH releasing factor (GRF). In the present study it is demonstrated that spontaneously hypertensive rats (SHR) of the Wistar-Kyoto strain display enhanced GH responses to clonidine as compared to normotensive Wistar-Kyoto control rats. In contrast, the GH responses to GRF are similar in hypertensive and normotensive animals. These findings indicate that brain alpha 2-adrenoceptors are more responsive in SHR than in normotensive controls. Since the enhanced GH responses to clonidine were observed also in young, prehypertensive SHR they are probably not secondary to the elevated blood pressure. The possible importance of an altered alpha 2-adrenergic neurotransmission for the development of elevated blood pressure in SHR is discussed.

Sexually differentiated actions of 3-PPP enantiomers on prolactin secretion

The ability of the enantiomers of the atypical dopamine receptor agonist 3-(3-hydroxyphenyl)-N-n-propylpiperidine (3-PPP) to counteract gamma-butyrolactone-induced hyperprolactinemia was compared in male and female rats. Following gamma-butyrolactone (GBL) pretreatment serum prolactin concentrations were higher in female than in male rats. In males (-)-3-PPP tended to be somewhat less effective than (+)-3-PPP in decreasing serum prolactin concentrations (levels after (+)-3-PPP and (-)-3-PPP: 21% and 33%, respectively, of levels in GBL-pretreated control(s). In females the (-)-form induced a much weaker response than did the (+)-form (levels after (+)-3-PPP and (-)-3-PPP: 8% and 74%, respectively, of levels in GBL pretreated controls). Parallel experiments replacing GBL by reserpine yielded similar results. Data are discussed in terms of sex differences in responsiveness of pituitary dopamine receptors.

Does alprazolam, in contrast to diazepam, activate alpha 2-adrenoceptors involved in the regulation of rat growth hormone secretion?

The conventional benzodiazepine diazepam and the novel triazolobenzodiazepine alprazolam were compared with respect to effects on growth hormone (GH) release in reserpine pretreated rats. The reserpine pretreatment was undertaken to eliminate brain monoaminergic influence on GH secretion, hence obtaining a low GH baseline from which a drug induced increase could be easily detected. Previous studies have indicated that activation of brain alpha 2-adrenoceptors is an indispensable prerequisite for GH release induced by other agents such as serotonin and opiate receptor agonists. In line with these findings, diazepam was found to induce GH release in reserpine pretreated rats only when the alpha 2-receptor agonist clonidine was simultaneously administered. In contrast, alprazolam caused a dose-dependent increase in plasma GH when given alone to reserpine pretreated rats. This effect of alprazolam was effectively antagonized by either of the two selective alpha 2-receptor antagonists yohimbine or idazoxane. The data indicate that alprazolam, but not diazepam, activates brain alpha 2-adrenoceptors involved in rat GH regulation. The possibility that an alpha 2-agonistic profile of alprazolam may contribute to the suggested effectiveness of the drug in the treatment of panic disorder is discussed.

Recurrence of respiratory depression following neurolept analgesia

Fentanyl, though generally regarded as a short-acting narcotic analgesic, can give unexpected respiratory depression several hours after the last dose. This potentially very dangerous effect is explained in pharmacokinetic studies by a mobilisation of fentanyl from tissue stores. In this report we describe a patient who, following a Harrington correction for scoliosis done with neurolept analgesia, developed a severe respiratory depression 5 h after the last dose of fentanyl.

High-pressure liquid chromatographic determination of acetylsalicylic acid, salicylic acid, diflunisal, indomethacin, indoprofen and indobufen

A high-pressure liquid chromatographic technique was developed which allowed concurrent measurement of acetylsalicylic acid (ASA) and salicylic acid (SA) in plasma. ASA was extensively deacetylated to SA not only in vivo but also in vitro, even in frozen plasma. The in vitro conversion could be prevented by physostigmine. In vivo, ASA was eliminated within few hours, whereas SA was continuously present following daily administration of conventional doses of ASA. A slight modification of a similar method, originally developed for naproxen determination [9], was found appropriate for measurement of the SA derivative diflunisal, of two non-SA antiinflammatory agents, indomethacin and indoprofen, and of a related anti-platelet agent, indobufen.

General health screening of four-year-olds in a Swedish country. V. A strategy for improving the effectiveness and the cost efficiency of the psychological screening program

Data presented in a previous paper pointed to the necessity for improving the overall sensitivity of the psychological screening program. The present report indicates possibilities for such an improvement without changing the screening methods. A comparison of the primary data of the true positives, the false positives and all the negatives (non-referred) revealed the necessity of more stringent referral criteria. It is predicted that the systematic application these criteria would result in an increase in the rate of true positives form 2.8 to 4.8% of the screened population. In addition a strategy aiming at a reduction of the costs without deteriorating the effectiveness and based on a differential application of the various elements of the screening program is presented.

General health screening of four-year-olds in a Swedish county. IV. An analysis of the effectiveness of the psychological examination program

Since 1969, 4-year-olds in the County of Uppsala have been offered extensive health screening at the Child Health Centres. In 1969 and 1970 a total of 3810 children underwent the screening procedure. The psychological screening instrument consisted of a questionnaire (to be answered by the parents), an interview of the parents, a psychomotor examination and an observation of the child's behaviour. 156 (4.1%) 4-year-olds were referred to a specialist team for investigation and decision concerning treatment. In the present study the effectiveness of the psychological screening instrument was assessed by its sensitivity, specificity and predictive value. The sensitivity was found to amount to a maximum of 0.73. The specificity was estimated to be 0.98-0.99, and the positive predictive value to 0.67. The authors consider the effectiveness to be sufficiently high to motivate continuation of the screening procedure for detection of psychological problems in pre-school age. Efforts should be made, however, to further improve the effectiveness.

Some Doubts about the Earth's Dust Cloud

Considerable doubt is cast on the validity of past satellite measurements of micrometeoroid fluxes in which piezoelectric microphones have been used as detectors. Data have been obtained from satellite and laboratory experiments which show that the microphone crystals emit noise when subject to slowly varying temperatures. The rate of noise is consistent with past flight data which have previously been interpreted on the basis of micrometeoroid impacts. These measurements have given rise to the theory that the earth is surrounded by a cloud of dust, although no satisfactory mechanism has yet been found to explain this apparent phenomenon. On the basis of the results reported here, it now appears that whether or not a concentration of dust exists in the vicinity of the earth, the data from satellite microphone measurements should not be used to support such a hypothesis.