Patient attitude and acceptance towards episiotomy during pregnancy before and after information provision: a questionnaire

INTRODUCTION AND HYPOTHESIS

Evidence regarding how women feel about episiotomies is not recorded in the literature. As the most common surgical procedure, there is a need to understand how women feel about episiotomy.

METHODS

The primary outcome was to identify the percentage of women who would accept an episiotomy if required. A literature review was compiled to provide nulliparous women in their third trimester with evidence-based information about episiotomies and perineal tears. Questions eliciting demographics, pre-information level of anxiety and acceptance of episiotomy were asked. After reading the information sheets, anxiety and knowledge were assessed again. Changes in anxiety levels from pre- to post-information were investigated using paired samples t tests. Because anxiety was measured on a scale, we assessed potential departures from normality by using the Wilcoxon signed-rank test. Questions also assessed the value women placed on this form of education.

RESULTS

There were 105 responses, with 88% accepting episiotomy, 2% declining and 10% seeking more information to decide. Eighty-one percent of women agreed that the information provided helped them to understand more about childbirth and 62% agreed that they felt more comfortable with the birthing process after reading the material. There was a reduction in anxiety levels regarding episiotomies after reading information (p = 0.002) and perineal tears (p = 0.02).

CONCLUSIONS

Most women will accept an episiotomy if required. Antenatal education about episiotomies is important to women and helps them feel more comfortable with the birthing process. Written information increases acceptance and reduces anxiety levels regarding episiotomies.

Impact of national guidelines on family history breast cancer surveillance

The breast cancer risk of women already under family history surveillance was accurately assessed according to national guidelines in an attempt to rationalize the service. Women attending two breast units in Glasgow between November 2003 and February 2005 were included. One thousand and five women under annual surveillance were assessed and had their relatives diagnoses verified. Four hundred and ninety-seven women were at significantly increased risk and eligible for follow-up. Five hundred and eight (50%) women attending were not eligible for family history surveillance, and 498 (98%) of these women accepted discharge. In conclusion, national guidelines have helped to more clearly define women who should undergo surveillance. This avoids unnecessary and potentially harmful routine investigations, and the service has been improved.

Prospective surveillance of women with a family history of breast cancer: auditing the risk threshold

To evaluate current guidelines criteria for inclusion of women in special ‘breast cancer family history’ surveillance programmes, records were reviewed of women referred to Scottish breast cancer family clinics between January 1994 and December 2003 but discharged as at ‘less than ‘moderate’ familial risk’. The Scottish Cancer Registry was then interrogated to determine subsequent age-specific incidence of breast cancer in this cohort and corresponding Scottish population figures. Among 2074 women, with an average follow-up of 4.0 years, 28 invasive breast cancers were recorded up to December 2003, where 14.4 were expected, a relative risk (RR) of 1.94. Eleven further breast cancers were recorded between January 2004 and February 2006 (ascertainment incomplete for this period). The overall RR for women in the study cohort exceeded the accepted ‘cutoff’ level (RR=1.7) for provision of special counselling and surveillance. The highest RR was found for the age group 45–59 years and this group also generated the majority of breast cancers. The National Institute for Clinical Excellence (‘NICE’) guidelines appear to be more accurate than those of the Scottish Intercollegiate Guidelines Network (‘SIGN’) in defining ‘moderate’ familial risk, and longer follow-up of this cohort could generate an evidence base for further modification of familial breast cancer services.

Is it worth pursuing surgery for epilepsy in patients with normal neuroimaging?

OBJECTIVE

To determine whether it is worth pursuing surgery for the treatment of epilepsy in patients with normal neuroimaging.

METHODS

Two patient populations were studied: (1) 136 consecutive patients who were surgically treated; (2) 105 consecutive patients assessed with chronically implanted intracranial electrodes within the same period. Sixty patients belonged to both groups, and included all 21 patients who had normal neuroimaging.

RESULTS

There were no differences in the proportion of patients with favourable outcome between those with normal and those with abnormal neuroimaging, irrespective of whether intracranial recordings were required. Among the 19 operated patients with normal neuroimaging, 74% had a favourable outcome (Engel's seizure outcome grades I and II), and among the 93 patients with abnormal neuroimaging, 73% had favourable outcome (p = 0.96). In patients with temporal resections, 92% of the 13 patients with normal neuroimaging had a favourable outcome, whereas among the 70 patients with abnormal neuroimaging, 80% had a favourable outcome (p = 0.44). In patients with extratemporal resections, two of the six patients with normal neuroimaging had a favourable outcome, while 12 of the 23 patients with abnormal neuroimaging had a favourable outcome (p = 0.65). Among the 105 patients studied with intracranial electrodes, five suffered transitory deficits as a result of implantation, and two suffered permanent deficits (one hemiplegia caused by haematoma and one mild dysphasia resulting from haemorrhage).

CONCLUSIONS

It is worth pursuing surgery in patients with normal neuroimaging because it results in good seizure control and the incidence of permanent deficits associated with intracranial studies is low.

Selective innervation of lamina I projection neurones that possess the neurokinin 1 receptor by serotonin-containing axons in the rat spinal cord

Axons containing serotonin descend from brainstem to spinal cord and are thought to contribute to stimulation-produced and opioid analgesia, partly by a direct inhibitory action of serotonin on projection neurones. The density of serotoninergic innervation is highest in lamina I, which contains many nociceptive projection neurones. Two sets of anatomical criteria have been used to classify lamina I projection neurones: somatodendritic morphology and presence or absence of the neurokinin 1 receptor. To test whether the strength of serotoninergic innervation of lamina I projection neurones was related to morphology or neurokinin 1 receptor expression, we used confocal microscopy to determine the density of serotoninergic contacts on 60 cells retrogradely labelled from the caudal ventrolateral medulla. The contact density on neurones with the neurokinin 1 receptor was variable, with some cells receiving heavy input and others having few contacts. However, on average they received significantly more contacts (5.64 per 1000 microm(2) plasma membrane +/- 0.47, S.E.M.) than neurones which lacked the receptor (2.49 +/- .36). Among the neurokinin 1 neurones, serotoninergic innervation density was not related to morphology. Since the majority of serotoninergic boutons in lamina I of rat spinal cord do not appear to form synapses, we carried out electron microscopy on three heavily innervated neurokinin 1 receptor-immunoreactive projection neurones. Symmetrical synapses were found at 89% of serotoninergic contacts. These results indicate that serotoninergic innervation of lamina I projection neurones in the rat spinal cord is related to expression of neurokinin 1 receptors, but not to morphology, and that (at least on heavily innervated neurones) most serotonin-containing boutons which are in contact form synapses.

MOR-1-immunoreactive neurons in the dorsal horn of the rat spinal cord: evidence for nonsynaptic innervation by substance P-containing primary afferents and for selective activation by noxious thermal stimuli

A direct action of mu-opioid agonists on neurons in the spinal dorsal horn is thought to contribute to opiate-induced analgesia. In this study we have investigated neurons that express the mu-opioid receptor MOR-1 in rat spinal cord to provide further evidence about their role in nociceptive processing. MOR-1-immunoreactive cells were largely restricted to lamina II, where they comprised approximately 10% of the neuronal population. The cells received few contacts from nonpeptidergic unmyelinated afferents, but many from substance P-containing afferents. However, electron microscopy revealed that most of these contacts were not associated with synapses. None of the MOR-1 cells in lamina II expressed the neurokinin 1 receptor; however, the mu-selective opioid peptide endomorphin-2 was present in the majority (62-82%) of substance P axons that contacted them. Noxious thermal stimulation of the foot induced c-Fos expression in approximately 15% of MOR-1 cells in the medial third of the ipsilateral dorsal horn at mid-lumbar level. However, following pinching of the foot or intraplantar injection of formalin very few MOR-1 cells expressed c-Fos, and for intraplantar formalin injection this result was not altered significantly by pretreatment with systemic naloxone. Although these findings indicate that at least some of the neurons in lamina II with MOR-1 are activated by noxious thermal stimulation, the results do not support the hypothesis that the cells have a role in transmitting nociceptive information following acute mechanical or chemical noxious stimuli.

Should needle localization breast biopsy give way to the new technology; the advanced breast biopsy instrumentation

Between July 1995 and June 1997, 114 consecutive women underwent 118 breast biopsies for nonpalpable lesions. A limited procedure room and local anesthesia were used in 96.5 per cent of patients. Intravenous access was not established in 95 per cent of patients. Oral diazepam was given to 51 per cent of patients. Needle localization technique was used with a success rate of 97.5 per cent and average operative time of 18 minutes. Breast carcinoma was found in 29 (24.6 per cent) biopsies. A review of 99 of the 118 mammograms showed only 45 per cent of the lesions being amenable to the new technology, the advanced breast biopsy instrumentation. Advantages of the needle localization include short operative time; supine position for the patient; easy access to control bleeding; ability to choose a cosmetic site for the skin incision; minimal tissue removal before reaching the lesion; ability to maintain a sterile field; and applicability to almost any mammographic lesion identified, whether single or multiple. Disadvantages include the need for a separate procedure to place the wire and potential of missing the lesion in 2.5 per cent, requiring additional surgery.

GABAergic neurons that contain neuropeptide Y selectively target cells with the neurokinin 1 receptor in laminae III and IV of the rat spinal cord

Neuropeptide Y (NPY) is contained in a population of GABAergic interneurons in the spinal dorsal horn and, when administered intrathecally, can produce analgesia. We previously identified a strong monosynaptic link between substance P-containing primary afferents and cells in lamina III or IV with the neurokinin 1 (NK1) receptor. Because some of these cells belong to the spinothalamic tract, they are likely to have an important role in pain mechanisms. In this study, we used confocal microscopy to examine the input to lamina III/IV NK1 receptor-immunoreactive neurons from NPY-containing axons. All of the cells studied received a dense innervation from NPY-immunoreactive axons, and electron microscopy revealed that synapses were often present at points of contact. Most NPY-immunoreactive boutons were also GABAergic, which supports the suggestion that they are derived from local neurons. The association between NPY-containing axons and NK1 receptor-immunoreactive neurons was specific, because postsynaptic dorsal column neurons (which were located in laminae III-V but did not possess NK1 receptors) and lamina I neurons with the NK1 receptor received significantly fewer contacts from NPY-immunoreactive axons. In addition, the NK1 receptor-immunoreactive lamina III/IV cells received few contacts from nitric oxide synthase-containing axons (which belong to a different population of GABAergic dorsal horn neurons). The NPY-containing axons appeared to be targeted to the NK1 receptor-immunoreactive neurons themselves rather than to their associated substance P-immunoreactive inputs. The dense innervation of these cells by NPY-containing axons suggests that they may possess receptors for NPY and that activation of these receptors may contribute to NPY-mediated analgesia.

Cells in laminae III and IV of the rat spinal cord that possess the neurokinin-1 receptor and have dorsally directed dendrites receive a major synaptic input from tachykinin-containing primary afferents

Many neurons with cell bodies in laminae III or IV of the spinal dorsal horn possess the neurokinin 1 receptor and have dorsal dendrites that arborize in the superficial dorsal horn. We have performed a confocal microscopic study to determine whether these cells receive inputs from substance P-containing primary afferents. All neurons of this type received contacts from substance P-immunoreactive axons, and in most cases the contacts onto dorsal dendrites were very numerous. A great majority (90-100%) of substance P-immunoreactive varicosities in contact with these cells were also immunoreactive with antibody to calcitonin gene-related peptide, indicating that they were of primary afferent origin. The density of contacts from substance P-immunoreactive varicosities onto these cells was significantly higher than that seen on cholinergic neurons in lamina III (which do not possess the receptor). Electron microscopy revealed that synapses were present at points of contact between substance P-immunoreactive boutons and dorsal dendrites of cells with the neurokinin 1 receptor. Some cells of this type belong to the spinothalamic tract, and we therefore examined neurons with cell bodies in laminae III or IV that possessed the neurokinin 1 receptor and were labeled retrogradely after thalamic injection of cholera toxin B subunit. These cells also received contacts from substance P-immunoreactive axons on their dorsal dendrites. The results of this study indicate that neurons of this type are a major target for substance P-containing primary afferents.

An ultrastructural study of the glycine transporter GLYT2 and its association with glycine in the superficial laminae of the rat spinal dorsal horn

The glycine transporter GLYT2 is present in axonal boutons throughout the spinal cord, and its laminar distribution matches that of glycine-enriched axons, which are presumed to be glycinergic. In order to determine whether boutons which possess GLYT2 are glycine-enriched, we have carried out pre-embedding immunocytochemistry with antibody raised against GLYT2, and combined this with post-embedding detection of glycine, in the rat. GLYT2 immunoreactivity was present in boutons which formed symmetrical axodendritic, axosomatic or axoaxonic synapses, and was often seen in peripheral axons of type II synaptic glomeruli. One hundred and fifty GLYT2-immunoreactive boutons were analysed quantitatively, and in 142 (94.6%) of these the density of gold particles representing glycine-like immunoreactivity exceeded the background level (over presumed glutamatergic boutons) by at least a factor of two. Within immunoreactive boutons, the GLYT2 reaction product was associated with the plasma membrane, but often appeared as discrete clumps and was generally excluded from the region of the active sites of synapses. These results confirm that GLYT2 is associated with glycine-enriched axonal boutons in the superficial dorsal horn. They also suggest that GLYT2 is unevenly distributed on the plasma membrane of these boutons, and raise the possibility that it may be excluded from synaptic clefts.

The mu-opioid receptor (MOR1) is mainly restricted to neurons that do not contain GABA or glycine in the superficial dorsal horn of the rat spinal cord

The mu-opioid receptor MOR1 is present on primary afferent axons and a population of neurons in the superficial dorsal horn of the rat spinal cord. In order to determine which types of neuron possess the receptor we carried out pre-embedding immunocytochemistry with antibody to MOR1 and combined this with a post-embedding method to detect GABA and glycine in the rat. MOR1 immunoreactivity was seen on many small neurons in lamina II and a few in the dorsal part of lamina III. Although immunostaining was mainly restricted to the cell bodies and dendrites of these neurons, in some cases it was possible to see their axons, and a few of these entered lamina III. One hundred and thirty-nine MOR1-immunoreactive cells were tested with GABA and glycine antibodies, and the great majority of these (131 of 139; 94%) were not GABA or glycine immunoreactive, while the remainder showed GABA but not glycine immunoreactivity. These results suggest that most of the cells in the superficial dorsal horn which possess MOR1 are excitatory interneurons. They support the hypothesis that part of the action of mu-opioid agonists, such as morphine, involves the inhibition of excitatory interneurons which convey input from nociceptors to neurons in the deep dorsal horn, thus interrupting the flow of nociceptive information through polysynaptic pathways in the spinal cord.

Colocalization of GABA, glycine, and their receptors at synapses in the rat spinal cord

To determine whether GABA and glycine can act as cotransmitters at synapses in the rat spinal cord, we have compared the ultrastructural distribution of GABAA-receptor beta 3 subunit with that of the glycine receptor-associated protein gephyrin and combined this with postembedding detection of GABA and glycine. We also used a dual-immunofluorescence method to confirm that gephyrin was associated with the glycine-receptor alpha 1 subunit throughout the cord. GABAA beta 3-subunit immunoreactivity was restricted primarily to synapses, and at a majority of these synapses the presynaptic axon was GABA-immunoreactive. Many synapses showed both GABAA beta 3 and gephyrin immunoreactivity, and at most of these synapses GABA and glycine were enriched in the presynaptic axon. These results strongly support the idea that cotransmission by GABA and glycine occurs in the spinal cord.

The types of neuron in spinal dorsal horn which possess neurokinin-1 receptors

In order to provide further information about the types of spinal neuron which possess neurokinin-1 receptors, we have carried out pre-embedding immunocytochemistry on sections of rat lumbar spinal cord with an antiserum raised against a synthetic peptide corresponding to part of the sequence of the receptor, and combined this with post-embedding immunocytochemistry to detect GABA and glycine. Numerous neuronal cell bodies showing neurokinin-1 receptor-immunoreactivity were seen in lamina I, laminae III-VI, the lateral spinal nucleus and the area around the central canal. Most of the cells observed in lamina III were small and had relatively restricted dendritic trees which could often not be followed into lamina II, however some larger cells in laminae III and IV had dendrites which extended through lamina II and into lamina I. Cells of the latter type are likely to represent a major target of substance P released from small-diameter primary afferents in the superficial dorsal horn. The great majority (255 out of 283) of spinal neurons which possessed neurokinin-1 receptor-immunoreactivity, including all of those in lamina I, were not GABA- or glycine-immunoreactive, however a few cells in the deep part of the dorsal horn and the lateral spinal nucleus and several cells near the central canal were GABA-immunoreactive, and some of these were also glycine-immunoreactive. These results suggest that substance P acts through neurokinin-1 receptors mainly on excitatory neurons within the spinal cord.

Awake patient monitoring to determine the need for shunting during carotid endarterectomy

BACKGROUND

The indications for shunt placement to prevent cerebral ischemia during carotid endarterectomy have been controversial. Some investigators have recommended empiric shunting for patients presumed to be at higher risk for cerebral ischemia with a recent stroke or severe stenosis or occlusion of the contralateral internal carotid artery.

METHODS

Carotid endarterectomy was performed in 81 cases with cervical block anesthetic, monitoring the awake patient for the development of cerebral ischemia (unresponsiveness or paralysis) during carotid clamping. The need for shunting (based on awake response) was compared in patients with the arbitrarily defined empiric indications for shunting (n = 29) versus those who did not have such clinical or anatomic findings (n = 52).

RESULTS

Cerebral ischemia requiring shunting was observed in five (17.2%) of 29 cases with the defined indications for empiric shunting. This was not different than the need for shunting in the control group where cerebral ischemia was seen in eight (15.4%) of 52 cases. No intraoperative neurologic events occurred in any case, but one (1.2%) patient suffered a postoperative transient ischemia attack and another (1.2%) had a postoperative stroke.

CONCLUSIONS

Empiric clinical or anatomic indications for shunting were not reliable predictors of cerebral ischemia that developed during carotid clamping in this study. Awake patient monitoring during carotid endarterectomy with regional anesthetic allowed prompt, accurate identification of patients with cerebral ischemia who would clearly benefit from placement of a shunt.

Ultrastructural evidence of axonal shearing as a result of lateral acceleration of the head in non-human primates

The concept of shearing of axons at the time of non-impact injury to the head was first suggested in the middle of this century. However, no experimental model of diffuse axonal injury (DAI) has provided morphological confirmation of this concept. Evidence from experiments on invertebrate axons suggests that membrane resealing after axonal transection occurs between 5 and 30 min after injury. Thus, ultrastructural evidence in support of axonal shearing will probably only be obtained by examination of very short-term survival animal models. We have examined serial thin sections from the corpus callosum of non-human primates exposed to lateral acceleration of the head under conditions which induce DAI. Tearing or shearing of axons was obtained 20 and 35 min after injury, but not at 60 min. Axonal fragmentation occurred more frequently at the node/paranode but also in the internodal regions of axons. Fragmentation occurred most frequently in small axons. Axonal shearing was associated with dissolution of the cytoskeleton and the occurrence of individual, morphologically abnormal membranous organelles. There was no aggregation of membranous organelles at 20 and 35 min but small groups did occur in some axons at 60 minutes. We suggest that two different mechanisms of injury may be occurring in non-impact injury to the head. The first is shearing of axons and sealing of fragmented axonal membranes within 60 min. A second mechanism occurs in other fibres where perturbation of the axon results in axonal swelling and disconnection at a minimum of 2 h after injury.

Differences in the fatty acid composition of the grey and white matter of different regions of the brains of patients with Alzheimer's disease and control subjects

In the present study, a comparison was made of the fatty acid composition of the grey and white matter of the frontal, parietal and parahippocampal regions of post-mortem brains of patients who had died with Alzheimer's disease (n = 15) and control postmortem subjects (n = 10). Diagnosis of Alzheimer-type disease was based on the presence of senile plaques and neurofibrillary tangles in post-mortem sections. Several highly significant and specific differences were observed between the two groups. Adrenic acid (22:4 n-6) was three to four times higher in the grey matter but lower in the white matter in each of the three regions in the Alzheimer brains than in the control group. These alterations were compensated by reciprocal changes in 18:0 in the grey matter and 16:1 fatty acids in the white matter. There was no significant difference in the proportion of other fatty acids, including those of the n-6 and n-3 series, in either the grey or the white matter of any of the three regions of the two groups, except for a higher proportion of 22:6 n-3 in the parietal white matter in the Alzheimer patients. There was no significant relationship between the levels of the individual fatty acids and age at death. It is suggested that the alterations in the fatty acid composition observed in the brains of Alzheimer patients may be caused by an aberration in the system by which essential fatty acids are transported into the brain.

The cerebrovascular response to experimental lateral head acceleration

A number of microvascular changes, such as the development of astrocyte lucency, increased endothelial pit/vesicle activity, development of crater like lesions, and endothelial microvilli have been reported after injury to the brain. Lateral head acceleration in the non-human primate, however, still provides the best experimental model for human diffuse axonal injury. No attempt has yet been made to document the spatial extent or time course of the microvascular response to acceleration injury to the head. We have examined the brains of baboons 1, 4, 6, and 12 h and 7 days after acceleration injury to the head to analyse the microvascular response. In the experimental animals there was a short-term rise in intracranial pressure followed by a long-term resolution, and a reduction in both mean arterial blood pressure and cerebral perfusion pressure which, however, never dropped below 75% of baseline for more than 5 min after injury in any animal. We found evidence for extravasation of blood in a small number of blood vessels in all parts of the brain. Interendothelial tight junctions are not disrupted. Pit/vesicle activity rises in the 1st h in the occipital cortex, but not until 4 h in the frontal cortex, and remains elevated for at least 7 days. There is little change in the thalamus. Development of microvilli is most rapid in the frontal cortex with peak values at 1 h, but slower in the thalamus and occipital cortex where peak values are only obtained at 6 h. Highest numbers of microvilli occur in parasagittal regions of the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

The isolation and characterization of high-density-lipoprotein subfractions containing apolipoprotein E from human plasma

1. Plasma high-density lipoprotein (HDL) was separated by heparin-Sepharose affinity chromatography into a non-bound, apolipoprotein E-poor, and a bound, apolipoprotein E-rich, fraction through the binding effect of Mn2+ in the column buffer. 2. The application of a series of elution buffers in which the concentration of Mn2+ was progressively replaced by Mg2+ resulted in the separation of the bound HDL into five subfractions. 3. Each subfraction migrated a different distance on gradient-gel electrophoresis. Three of the subfractions had RF (relative migration compared with BSA) values within the range of HDL2b. One subfraction contained largely HDL2a, with some material in the regions of HDL2b and HDL3a, and one subfraction spanned the RF regions of HDL2a, HDL3a and HDL3b. 4. The number of molecules, per HDL particle, of cholesteryl ester, non-esterified cholesterol and phospholipid increased with particle size, whereas triacylglycerol passed through a maximum and the number of amino acid residues remained approximately the same. 5. Apolipoprotein (apo) A-I was the major apoprotein in all five subfractions, but the latter differed appreciably in their contents of apo A-II and apo E. 6. The major fatty acid component of each subfraction was linoleic acid, with moderate amounts of C16:0 and C18:1 fatty acids and a smaller content of C18:0, C20:4,n-6 and C22:6,n-3, with no significant difference in composition between the subfractions. 7. This paper provides the first description of a method for the isolation of three subfractions of HDL2b together with other subfractions in quantities that are sufficient for further analytical or metabolic studies.

Changes in the choroid plexus, responses by intrinsic epiplexus cells and recruitment from monocytes after experimental head acceleration injury in the non-human primate

We have examined, by scanning and transmission electron microscopy, morphological changes in the choroid plexus of the lateral ventricles of the non-human primate brain after lateral head acceleration. We demonstrate passage of plasma and blood cells either through tears in blood vessels and the choroidal epithelium, or through the cells of the choroidal epithelium, 20 min after injury, together with morphological changes in that epithelium. At 3 and 4 h small cells with a reniform nucleus accumulate in the connective tissue core of the choroid plexus. We suggest that these are monocytes. At 6 and 12 h cells can be seen in enlarged intercellular spaces within the choroidal epithelium. These cells possess surface ruffles and we suggest that they are monocytes differentiating into macrophages and epiplexus cells. Further evidence for transepithelial migration of monocytes/macrophages is obtained at 7 days. However, at 28 days all blood has been removed from the surface of the choroid plexus and epiplexus cells possess an appearance typical of that in uninjured animals. The possible sources of epiplexus cells are discussed with reference to studies of responses after brain insult and of development. We have obtained no evidence in support of emperipolesis by monocytes through the choroidal epithelium. We suggest that monocytes/macrophages migrate, via an intercellular route, to differentiate into epiplexus cells, thus providing additional numbers of epiplexus cells after head injury.

Localisation of calcium ions and calcium-ATPase activity within myelinated nerve fibres of the adult guinea-pig optic nerve

There is no published description of the distribution of free Ca2+, nor of the distribution of Ca(2+)-ATPase activity associated with the maintenance of low axoplasmic Ca2+ concentrations, in normal central myelinated nerve fibres. We have used the oxalate-pyroantimonate technique to localise free Ca2+, together with the lead-citrate technique to localise Ca(2+)-ATPase activity within myelinated fibres from the adult guinea-pig optic nerve. Pyroantimonate precipitate occurred within the axoplasm at nodes of Ranvier and the internode, at areas of myelin disruption, within Schmidt-Lanterman incisures (SLI) and glial paranodal loops. But precipitate was absent from the axoplasm beneath SLI and at the paranode. Ca(2+)-ATPase activity was localised in axonal smooth endoplasmic reticulum (SER), the outer membrane of mitochondria, the nodal axolemma, the glial membranes of the paranodal loops, the SLI and the external aspect of the myelin sheath. We have demonstrated large domains within the axons of CNS fibres where calcium is present or absent. Moreover, we have shown that, where calcium is absent, there is localisation of Ca(2+)-ATPase activity, which would serve to remove calcium from the adjacent axoplasm. Our results are compared with information obtained from PNS fibres and some differences of distribution discussed.

The microvascular response to stretch injury in the adult guinea pig visual system

In a variety of brain injury models, both reactive axonal change and microvascular abnormalities occur. Development of a stretch injury model in the guinea pig optic nerve has allowed for the characterization of the early axonal response to injury. In this same model, we have now attempted to characterize those morphologic changes occurring in the visual system microvasculature after injury. Thirty adult guinea pigs were subjected to axonal stretch injury and killed at posttraumatic survival periods ranging from 10 minutes to 14 days. Twenty animals were examined by scanning electron microscopy (SEM) for the detection of posttraumatic changes in the surface morphology of the microvasculature, and 10 animals were processed for transmission electron microscopy (TEM) analysis. Through this approach, increased pit vesicle activity and formation of endothelial microvilli were recognized within 10 minutes of injury. Pit vesicle activity returned to control levels by 2 hours. The formation of endothelial microvilli was widespread, affecting the microvessels in both the stretched and unstretched optic nerves and in the chiasm. The greatest response developed most slowly in the stretched nerve, and it was faster but less marked in the unstretched nerve and chiasm. Microvilli were more numerous in larger vessels. Related astrocytic swelling/lucency was not apparent until 6 hours after injury. The astrocyte response was less marked than that documented after brain injury. The results of this investigation demonstrate a widespread microvascular response to stretch injury of the guinea pig optic nerve. Comparison with the documented responses to traumatic brain injury indicates different rates of response to different types of insult.

Reduced postprandial skeletal muscle blood flow contributes to glucose intolerance in human obesity

While it is well accepted that the disposal of an oral glucose load (OGL) occurs primarily in skeletal muscle, the mechanisms by which this occurs are not completely elucidated. Glucose uptake (GU) in skeletal muscle follows the Fick principal, such that GU equals the products of the arteriovenous glucose difference (AVGd) across and the blood flow (BF) into muscle. It is widely believed that in the postprandial period both insulin and glucose increase GU by increasing the AVGd; however, a role for increments in BF in the disposal and tolerance of an OGL has not been established. To investigate this issue, whole body GU (isotope dilution), leg GU (leg balance technique), leg BF, and cardiac index (CI) were measured after an overnight fast and over 180 min after an OGL (1 g/kg) in 8 lean (ln) and 8 obese (ob) subjects [mean +/- SEM age, 36 +/- 2 vs. 37 +/- 2 yr (P = NS) and 60 +/- 1 vs. 99 +/- 5 kg (P less than 0.01), respectively]. Serum glucose levels were higher in the ob than in the ln subjects between 100 and 160 min, indicating reduced glucose tolerance. Fasting and post-OGL serum insulin levels were 2- to 3-fold higher in ob vs. ln at all times, indicating insulin resistance. Peak (40-80 min) incremental whole body GU above baseline was 32% lower in ob vs. ln, (P less than 0.05). Peak femoral AVGd was not different between ob and ln (0.55 +/- 0.16 vs. 0.66 +/- 0.14 mmol/L; P = NS). Peak leg BF increased 36% over baseline in ln (0.328 +/- 0.052 to 0.449 +/- 0.073 L/min; P less than 0.05), while ob subjects displayed no change in leg BF from baseline. Consequently, peak leg GU was 44% lower in ob vs. ln (P less than 0.05). CI increased 24% from baseline at 60 min in ln (P less than 0.05), but was unchanged in ob. In summary, after an OGL 1) femoral AVGd increases in both ln and ob subjects, but skeletal muscle BF and CI increase in ln only; 2) since peak femoral AVGd values were similar in ln and ob, differences in peak leg GU and (by inference) whole body GU are largely due to reduced BF to insulin-sensitive tissues; and 3) hemodynamics play an important role in the physiological disposal of an OGL, and therefore, hemodynamic defects can potentially contribute to reduced glucose tolerance and insulin resistance.

The effect of clomipramine treatment on plasma lipoproteins and high density lipoprotein subfractions in healthy subjects

The effect of clomipramine on plasma lipoproteins, including high density lipoprotein (HDL) subfractions in five healthy males was investigated. The concentrations of total plasma cholesterol and low density lipoprotein cholesterol decreased slightly while that of total HDL-cholesterol showed a small increase, giving a decrease (p less than 0.05) in the ratio of total plasma cholesterol to HDL-cholesterol. The level of HDL2-cholesterol increased (p less than 0.01) with clomipramine treatment while there was no significant change in the concentration of HDL3-cholesterol. Gradient gel electrophoresis showed that administration of the drug was associated with an increase in the relative concentration of HDL2a as well as of HDL2b and a decrease in that of HDL3b/3c. The plasma concentration of apolipoprotein (Apo) A-I showed a small but insignificant increase. These changes in lipoprotein profile are characteristic of those associated with a decrease in coronary risk.

Calculating cardiac output from transmitral volume flow using Doppler and M-mode echocardiography

To simplify transmitral volume flow determination by Doppler echocardiography, a formula for calculating mean mitral valve orifice area using M-mode echocardiography without any 2-dimensional measurements was developed and evaluated in this study. The maximal mitral orifice area was assumed to be circular and its diameter was calculated from the maximal M-mode mitral leaflet separation. The maximal area was multiplied by the mean to maximal anterior mitral leaflet excursion ratio to correct for phasic changes in flow orifice area during ventricular filling. This measurement had a high correlation (r = 0.97, standard error of the estimate + 0.26 cm2) with mean mitral valve orifice area calculated from frame-by-frame analysis of short-axis 2-dimensional echoes in a select group of 10 normal volunteers and 10 patients with cardiomyopathy who had very high quality images of the mitral valve leaflet tips. Cardiac output calculated using the new method for orifice area estimation combined with apex view mitral valve Doppler velocities was then validated in 48 consecutive patients undergoing thermodilution cardiac output determinations with a close correlation between Doppler and thermodilution cardiac output (2.3 to 6.1 liter/min, r = 0.93, standard error of the estimate = 362 ml). The correlation improved when 12 patients with mild mitral insufficiency were excluded (r = 0.95). The M-mode echocardiogram-derived mitral valve orifice method combined with Doppler mitral valve velocities is accurate, easy to perform, has a high success rate and should increase the applicability of Doppler echocardiography for estimation of cardiac output.

The acute effect of marathon running on plasma lipoproteins in female subjects

The acute effect of running a 42.2 km marathon race on plasma lipoproteins was investigated in 12 female subjects (aged 21 to 41 years). During the race there was a significant increase (P less than 0.01) in the concentration of total plasma cholesterol. The mean post-race concentration of high density lipoprotein cholesterol (HDL-C) was 64.0 +/- 16.2 (SD) mg 100 ml-1, compared with 52.1 +/- 14.0 mg 100 ml-1 before the race, representing a significant increase (P less than 0.002). There was no significant difference in the concentration of very low density lipoprotein (VLDL) or low density lipoprotein (LDL) before and after the exercise. The mean concentration of the cholesteryl ester moiety of the HDL increased from 43.7 +/- 12.3 to 54.3 +/- 15.7 mg 100 ml-1 (P less than 0.002), while there was no significant changes in the concentration of the unesterified cholesterol, phospholipid, triacylglycerol or protein moieties of the HDL. The relative proportions of apolipoproteins A-I, A-II, C and E remained unchanged during the exercise. The changes in the concentration of each of the lipoprotein fractions observed during the marathon varied considerably between subjects. The individual increases in the concentration of HDL-C ranged from 4.1 to 28.4 mg 100 ml-1, while both increases and decreases in individual concentrations of VLDL and LDL as well as of total plasma cholesterol were observed. These observations suggest that women undergo greater changes in HDL-C concentration that men during acute exercise, while considerable variation between individuals occurs.

Drinking and creativity: objective and subjective effects

A literature characterized by considerable speculation but a paucity of empirical studies prompted this experiment on the relation between drinking and creativity. After being queried about how they believed alcohol would affect their creative performance, 40 male undergraduate social drinkers were assigned to one of four treatments in a balanced placebo design. Those actually receiving alcohol consumed a mixture containing .6 g of ethanol per kg of body weight. All subjects then completed the entire Figural portion and the Unusual Uses subtest of the Verbal portion of the Torrance Tests of Creative Thinking. Posttesting explored subjects' own evaluations of their creative products and the kinds of attributions they made about factors contributing to the outcomes. Results showed minimal effects of beverage manipulations on measured creativity even when a priori belief and concurrent mood scores were covaried. However, those individuals who thought they had received alcohol gave significantly more positive evaluations of their creative performances than did subjects who believed they were in the non-alcohol treatments. Subjects did not attribute changes in creativity to drinking. Theoretical and practical implications of these findings were discussed.

Damage to the surface of the small intestinal villus: an objective scale of assessment of the effects of single and fractionated radiation doses

Scanning electron microscopy has been used to compare damage to mouse small intestinal mucosa after irradiation with different doses of photons and neutrons. Various stages of the collapse of villous structure seen after radiation include the production of conical and rudimentary villi and a flattened mucosa. A scale is proposed to relate radiation to villous damage. Points from this scale are taken to produce comparative ratios for equivalent damage produced by different radiation conditions. RBE values are quoted for neutron. X and gamma radiation given as single or fractionated irradiation doses and as whole or partial body irradiation. The relationship between the stroma in intravillous pegs and that of the pericryptal compartment is explored.

Scanning electron microscopy, autolysis, and irradiation as techniques for studying small intestinal morphology

Examination of autolysed control mouse small intestine using scanning electron microscopy has revealed details of the connective tissue components of the mucosa. The cores of the villi are seen collapsed across the intervillous basin. Crypts of Lieberkuhn are seen as tubular channels stretching down from the intervillous basin. Sometimes the crypts are split in two by a connective tissue septum. The mouths of the crypts of Lieberkuhn are, in general, arranged in double rows between the single rows of villi. The ratio of number of crypts to numbers of villi was calculated as 5.01:1. This is close to the figure of 4.53:1, as quoted by Smith & Jarvis (1980) who used differential interference contrast microscopy to investigate the crypt to villus ratio. After radiation, the severe drop in the number of crypt mouths can be clearly seen by the combination of autolysis and scanning electron microscopy: the rows of crypt mouths between the villi have been lost, and many crypt mouths have been occluded by stromal tissue. The arrangement of the crypt mouths and the observation of mucosal abnormalities after irradiation have led to the postulation that cells leaving the crypt mouths move in a spiral manner towards and then up the villous surface: this postulated movement might imply an asymmetry in some properties of enterocytes. The use of scanning electron microscopy in conjugation with autolysis and irradiation has thus forced a critical re-examination of the relationships between crypts and villi.

Multinucleate giant enterocytes in small intestinal villi after irradiation

Scanning electron microscopy of the small intestine of the mouse 5 days after X- or neutron irradiation has revealed the formation of giant cells on the villus surface. Correlative light microscopy and transmission electron microscopy have shown that these giant cells are syncytial in nature. Characteristic features of lipid inclusions and apical microvilli suggest tha these syncytia are giant enterocytes. It has also been shown that these giant cells are in contact with the connective tissue core of the villus and have a close contact with the normal enterocytes, thus maintaining mucosal integrity. It is postulated that radiation damage has caused incomplete separation during mitosis and that attempted division occurs outside the crypts of Lieberkuhn.

Scanning electron microscopy and resin histology of large bowel biopsies

The mucosal surface of human colon in 18 adults and children was examined by S.E.M. with subsequent resin histology and transmission electron microscopy of the same specimen. Results showed that this technique contributed useful information on the mucosa in health and in disease.

Surface damage in the small intestine of the mouse after X - or neutron irradiation

Damage after X-irradiation includes lateral villous collapse, progressing after 3 - 5 days to villi which sometimes show signs of vertical collapse. After neutron irradiation vertical villous collapse is established earlier, with less swelling of villous tips. It seems, therefore, that at radiobiologically equivalent doses, neutron and X-irradiation produce different levels of surface damage, with neutron irradiation being the more destructive. Early villous tip damage may perhaps be due to disruption of susceptible cells already at the extrusion zone, or to stromal damage.

Lack of correlation between villus and crypt damage in irradiated mouse intestine

It has been observed that scanning electron microscopy is a more sensitive indicator of mucosal damage at low radiation dose levels than conventional quantitative crypt counting techniques. Three different fractionation schedules were subjected to investigation by both of these methods to try to elucidate some features of irradiation damage to the whole of the intestinal mucosa, at dose levels commonly used in clinical practice. Despite variations in the qualitative observations, there was a marked difference in two of the schedules between damage expressed as crypt counts and that described by the qualitative techniques. In the first case high crypt numbers were associated with severe mucosal damage, whereas the second schedule produced a reduced crypt count in association with low damage to the surface mucosa. A third schedule produced results in which there was a general agreement between low crypt numbers and considerable surface mucosal damage. However, observations were made of mucosal formations not previously seen on damaged mucosal surfaces. These resembled the appearance normally associated with the gut of patients suffering from coeliac disease. Variations in the qualitative observations were seen in all the schedules so that their interpretation in terms of perturbation of cellular kinetics is difficult.

Hypersensitivity reactions in the small intestine. IV. Influence of allograft rejection on small intestinal mucosal architecture: a scanning and transmission electron microscope study

The effect of a local delayed hypersensitivity reaction (allograft rejection) on small intestinal architecture has been examined by using scanning electron microscopy of the mucosal surface. In isografts, regarded as a morphological basis for normality of the system, the villi appeared normal and finger like. In allografts the appearances ranged from fairly normal areas to others with stunted and ridged villi, and flat areas in which crypt mouths opened on to the flat mucosal surface. The fine structure of epithelial cells was studied further by transmission electron microscopy. There was an apparent reduction in the size of the microvillous border in allografts but no other consistent abnormality. The similarities between this model of allograft rejection, and untreated coeliac disease in man, are highlighted and contrasted with the effects of acute radiation injury on the intestine.