Extent of the ipsilateral representation in the ventral posterior medial nucleus of the monkey thalamus

Summary Single and multiunit mapping was used to determine the extent of the representation of ipsilateral structures in the ventral posterior medial (VPM) nucleus of the thalamus in cynomolgus monkeys. The extent of the VPM occupied by terminations of afferent fibers arising in the ipsilateral principal trigeminal nucleus was also determined by anterograde transport of horseradish peroxidase. Both methods indicate that most of the medial half of VPM is occupied by the ipsilateral representation. This is much larger than previously suspected. Units in the medial half of VPM have small, well localized receptive fields on the ipsilateral side of the lower lip, tongue and palate, in the ipsilateral cheek pouch and on the ipsilateral teeth. The representation is largest for the ipsilateral side of the tongue and the cheek pouch. Most units in the lateral half of VPM have small, contralateral receptive fields. Few units in VPM have bilateral receptive fields. VPM is clearly distinguishable by cytochrome oxidase (CO) staining. Anteroposteriorly elongated, CO-positive aggreations correspond to elongated aggregations of units with the same or closely similar receptive fields, especially in the medial, ipsilateral representation.Abbreviations CL Central lateral nucleus - CM Centre médian nucleus - DCN Dorsal cochlear nucleus - DIT Dorsal ipsilateral trigeminal tract - IO Inferior olivary nuclei - ML Medial lemniscus - MV Motor trigeminal nucleus - PRV Principal sensory trigeminal nucleus - SO Superior olivary nuclei - SPV Spinal trigeminal nucleus - Ves Vestibular nuclei - VMb Basal ventral medial nucleus - VPI Ventral posterior inferior nucleus - VPL Ventral posterior lateral nucleus - VPM Ventral posterior medial nucleus - IV Trochlear nucleus - VI Abducens nucleus     

Distribution of substance P receptor binding in dorsal column nuclei of rat, cat, monkey and human

In the present study, substance P receptor binding was localized in the dorsal column nuclei (DCN) of the rat, cat, monkey, and human. Bolton–Hunter-labeled [¹²⁵I]substance P binding was most concentrated in the cell nests of the core region, but was present throughout the DCN of each species. The distribution of substance P receptors may reconcile apparent mismatches between the widespread responsiveness of DCN neurons to substance P and the restricted distribution of substance P containing afferents.     

A simple Duplex-PCR to evaluate the DNA quality of anthropological and forensic samples prior short tandem repeat typing

Typing of DNA from ancient or otherwise highly degraded material, e.g. formalin fixed tissues, can be difficult, time consuming and costly. Very often, genetic typing is not possible at all. We present an inexpensive and easy to use Duplex-PCR that amplifies a 164 bp fragment specific for nuclear DNA together with a 260 bp mitochondrial DNA fragment and that can be employed as a pretest prior to short tandem repeat (STR) typing. All together, we analyzed DNA from 20 ancient bones, 20 formalin fixed tissues and 20 other forensic samples in different concentrations. Each sample that failed in the presented Duplex-amplification was also negative for STR typing, while samples that showed strong and clear signals in the Duplex-PCR led to reproducible genetic profiles using the multiplex kits AmpFLSTR Identifiler and Powerplex ES. The Duplex-PCR worked as a reliable indicator of DNA quality in the sample.     

CYP1A1 and CYP1B1, two hydrocarbon-inducible cytochromes P450, are constitutively expressed in neonate and adult goat liver, lung and kidney.

The ontogeny of cytochrome P-450 isozymes (P450) in goat liver, lung and kidney was studied using anion exchange HPLC separation of solublized microsomal proteins and Western immunoblotting. Comparison of the overall HPLC profile of goat P450 isozymes between liver, lung and kidney showed that while the P450's of goat liver were equally separated into five peaks of isozyme(s), only two peaks constitute the majority of P450 isozyme(s) in lung and kidney, thus demonstrating the tissue specific differences in P450 isozyme distribution in goats. Immunoblotting analysis using polyclonal antibodies against rat CYP1B1, and mouse CYP1B1, polyaromatic hydrocarbon-regulated P450's, revealed that goat orthologs of CYP1A1 and CYP1B1 are expressed constitutively in goats. The CYP1A1 was expressed in goat liver and lung as early as 1st day of age, and the levels of its expression in adult lung and liver were, respectively, 1.3 and 5.5 pmol per mg microsomal proteins. CYP1B1 was expressed in goat livers in substantial levels as of 1 week of age and increased thereafter to reach approximately 4.5 pmol per mg microsomal proteins in adult livers, while low level was detectable only in adult but not neonate lung tissues. Furthermore, polyclonal antibodies against rat CYP1A2 detected very high levels of CYP1A2 in livers of adult and 6 week old goats. The Ah receptor which controls the expression of CYP1A1/1A2 and CYP1B1, was detected in cytosolic fractions from these tissues as a 104 kDa and a minor level of the 106 kDa form. These are potentially very important findings in light of the role of CYP1A1/1A2 and CYP1B1 in activation of polyaromatic hydrocarbons, heterocyclic amines and nitroaromatic hydrocarbons to genotoxic metabolites, and the health consequences of these metabolites on humans, as consumers of goat milk and meat. Using polyclonal antibodies against rat hepatic CYP2B1 and CYP3A1, the goat CYP2B and CYP3A forms were not detectable in livers of goats at any age, but lungs of adult and 6 week old goats expressed these two CYPs in levels equivalent to the livers of phenobarbital-induced rats. On the other hand, anti-rat CYP2C6 antibodies specifically detected two goat ortholog forms which were expressed in all three tissues and exhibited age-dependent changes. In conclusion, results from both immunoblot and HPLC analyses confirmed that, as in other species, the expression of P450 isozymes in goat is under both developmental- and tissue-specific regulatory factors.     

The development of hepatic drug-metabolizing enzyme activity in the neonatal calf and its effect on drug disposition

Mixed function oxidase and UDP-glucuronyltransferase activity was measured in liver microsomal preparations from 1-, 7-, and 42-day-old, male, Holstein calves. Liver samples were obtained by a surgical biopsy procedure that allowed for multiple samples to be taken from a single individual. Microsomal protein content doubled between 7 and 42 days of age and reached adult levels during this time. Cytochrome P-450 content increased 2-fold during the first week and remained constant thereafter. NADPH-cytochrome c reductase activity doubled during the first week, but then returned to its initial level by 42 days of age. UDP-glucuronyltransferase activity was well developed at 1 day of age and reached adult levels by 7 days of age. Mixed function oxidase activity was less well developed; activities at 1 day of age were only 17-50% of those at 42 days of age for O-deethylation, O- and N-demethylation, and aryl hydrocarbon hydroxylation. Development of hepatic drug-metabolizing activity was discussed in relation to the age-related increase in the rate of elimination of the antibacterial compound trimethoprim.     

Thrombolytic therapy for acute ischaemic stroke in octogenarians: selection by magnetic resonance imaging improves safety but does not improve outcome

Background

Owing to the fear of an increased bleeding risk, thrombolytic therapy is withheld from many patients with acute stroke >80 years of age.

Objective

To analyse the risk for symptomatic intracranial haemorrhage (sICH), morbidity and mortality after thrombolytic therapy in octogenarians focusing, in particular, on whether patients selected using magnetic resonance imaging (MRI) had a better risk:benefit ratio.

Methods

The prospectively collected single‐centre data of all patients treated with systemic thrombolytic therapy for acute ischaemic stroke since 1998 (n = 468) were reviewed, and patients ⩾80 years (n = 90) were compared with those aged <80 years (n = 378). In addition, the group of octogenarians was analysed with respect to initial imaging modality.

Results

The overall rate of sICH in the octogenarians was 6.9%, compared with 5.3% in younger patients (p = 0.61). In older patients selected by computed tomography, the rate of sICH was 9.4%; no patient selected by MRI had sICH (p = 0.10). Mortality in the octogenarians selected by computed tomography was 29.7% after 3 months as compared with 26.9% in the patients selected by MRI (p = 1.0). 20.3% of the octogenarians selected by computed tomography and 15.4% of those selected by MRI had a favourable outcome (modified Rankin scale ⩽1) after 3 months (p = 0.77).

Conclusion

Compared with younger patients, octogenarians do not have an increased risk of sICH. The use of MRI to select octogenarians for thrombolytic therapy seemed to decrease the risk of sICH, but did not influence the overall outcome after 3 months.The incidence of stroke increases steeply with age. In a population‐based survey, incidence of a first‐ever stroke was around 0.8 per 1000 population per year in people aged <75 years as compared with 14 per 1000 population per year in those aged 75–84 years and 29 per 1000 population per year in those aged >85 years.¹ With respect to changes in the population''s age structure in the industrialised world, the number of acute vascular events in elderly people will almost double in the course of the next 25 years.¹ Furthermore, age is an independent predictor for poor outcome after ischaemic stroke. Older patients, especially those aged >80 years, have a higher in‐hospital mortality risk and a favourable functional outcome is less likely.² Intravenous thrombolysis with recombinant tissue‐type plasminogen activator (rt‐PA) is the only approved therapy for patients with acute ischaemic stroke. However, the European and Australian rt‐PA stroke trials excluded patients >80 years of age.^3,4,5 Older patients were only allowed to be enrolled in the National Institute of Neurological Disorders and Stroke (NINDS) rt‐PA stroke study, but a mean age of 69 years in this trial shows that few patients >80 years of age were actually included.⁶ Owing to the lack of knowledge about the safety and efficacy of thrombolysis in this age group from randomised trials, the European Medicines Evaluation Agency (EMEA) recommends that rt‐PA not be used in patients with ischaemic stroke aged >80 years.⁷In the past few years, it has become increasingly popular to select patients for thrombolytic therapy using multiparametric magnetic resonance imaging (MRI) techniques. Our objective was to analyse the morbidity, mortality and risk for symptomatic intracranial haemorrhage (sICH) after thrombolytic therapy in octogenarians, focusing in particular on whether the risk:benefit ratio was higher in patients selected by MRI.     

Femoral artery diameter and arteriogenic cytokines in healthy women

Animal studies have identified monocyte chemoattractive protein-1 (MCP-1) and vascular endothelial growth factor (VEGF) as critical mediators of arterial diameter enlargement in response to chronic increases in blood flow (arteriogenesis). Furthermore, cellular studies have shown that the shear stresses resulting from increased blood flow stimulate synthesis of MCP-1, which in turn stimulates synthesis of VEGF. The purpose of this study was to determine if these mechanisms are evident in healthy women. Resting femoral artery diameter and blood flow, lean leg mass, MCP-1 and VEGF concentrations, and aerobic capacity were measured in 34 healthy women along with plasma concentrations of lipids associated with cardiovascular disease risk. Femoral artery diameter was independently related to metabolically active (lean) leg mass (b = 0.41, P = 0.008) and aerobic capacity (b = 0.45, P = 0.004). Plasma MCP-1 correlated negatively with the ratio of femoral artery diameter to lean leg mass (b = ? 0.42, P = 0.009) and positively with serum triglycerides (b = 0.46, P = 0.005). Plasma VEGF exhibited similar correlations and strongly correlated with MCP-1 (R = 0.92, P < 0.0001). The results indicate that circulating MCP-1 and VEGF concentrations are associated with both arteriogenic and atherogenic stimuli in healthy women.     

Cat area 17. I. Pattern of thalamic control of cortical layers

Reversible inactivation of individual layers of the cat lateral geniculate and medial interlaminar nuclei was used to investigate the necessary and sufficient inputs for maintaining visually driven activity and receptive field properties in area 17. Neither orientation selectivity nor direction selectivity depends on any individual geniculate layer. We identified two groups of cortical layers on the basis of the pattern of thalamic inputs providing visual driving through the contralateral eye. One group, consisting of layers 4 and 6, has geniculate layer A as its only necessary and sufficient input. The other, consisting of supragranular layers, integrates at least two sufficient thalamic inputs, one of which is layer A. Several major receptive field properties are independently generated in these two groups of layers.     

Cat area 17. IV. Two types of corticotectal cells defined by controlling geniculate inputs

The dependence of cat area 17 corticotectal (CT) cells on specific subdivisions of the dorsal lateral geniculate (LGN) and medial interlaminar nuclei (MIN) was examined using reversible inactivation techniques. Inactivation of layer C of the LGN or layer 1 of the MIN did not block visual activity of CT cells driven through the contralateral eye. Inactivation of layer A of the LGN revealed two populations of CT cells: one strongly dependent on layer A and one whose visually driven activity survived layer A inactivation. CT cells that responded best to short stimuli (special complex cells) were least dependent on layer A, whereas cells that responded best to long stimuli (standard complex cells) were most dependent on layer A. We propose a model of the intracortical circuitry of these two types of CT cells. Standard complex cells, which are heavily dependent on layer A, receive sustaining visual input through layers 4 and/or 6. Special complex cells, which are not dependent on any single layer of the lateral geniculate nucleus, receive sustaining visual input from supragranular layers.