A factor model of the functional psychoses and the relationship of factors to clinical variables and brain morphology

BACKGROUND

Despite more than 100 years of study, there remains no definitive diagnostic validation of the functional psychoses. Factor analysis suggests the presence of three or more psychopathological syndromes in functional psychoses as a whole. The relationship between these factors and cerebral anatomy has been investigated in schizophrenia only. This study aimed to address the relationship of symptom factors to clinically important variables and cerebral anatomy in a sample of psychotic patients with a spread of diagnoses.

METHODS

In a sample of patients with functional psychoses, symptom data was obtained on four consecutive admissions using the OPCRIT symptom checklist. OPCRIT data was used to generate operational diagnoses in accordance with pre-set criteria and a principle components analysis was performed on symptom data. Factor loadings were compared between each admission to examine factor stability over time. Factor scores at first admission were also correlated with clinical variables obtained from patients' case notes. From the sample of 204 patients, 64 subjects were recruited and underwent an MRI scan of the brain. Regional anatomical volumes were compared with diagnosis and factor loadings at first admission.

RESULTS

A principal components analysis gave a four-factor solution of 'manic', 'depressive', 'disorganization' and 'reality distortion' factors at each admission. Factors showed a high degree of stability over the four admissions studied. The factors were significantly associated with several clinical variables. Three of the four factors were associated with a specific pattern of cerebral anatomy.

CONCLUSIONS

This study suggests that factors may correspond to relatively specific disease processes underlying functional psychotic illness. We propose that the use of symptom factors may facilitate the investigation of the underlying mechanisms of psychotic illness.

Epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is a model imprinting disorder resulting from mutations or epigenetic events involving imprinted genes at chromosome 11p15.5. Thus, germline mutations in CDKN1C, uniparental disomy (UPD), and loss of imprinting of IGF2 and other imprinted genes have been implicated. Many familial BWS cases have germline CDKN1C mutations. However, most BWS cases are sporadic and UPD or putative imprinting errors predominate in this group. We have identified previously a subgroup of sporadic cases with loss of imprinting (LOI) of IGF2 and epigenetic silencing of H19 proposed to be caused by a defect in a distal 11p15.5 imprinting control element (designated BWSIC1). However, many sporadic BWS patients show biallelic IGF2 expression in the presence of normal H19 methylation and expression patterns. This and other evidence suggested the existence of a further imprinting control element (BWSIC2) at 11p15. 5. Recently, we showed that a subgroup of BWS patients have loss of methylation (LOM) at a differentially methylated region (KvDMR1) within the KCNQ1 gene centromeric to the IGF2 and H19 genes. We have now analysed a large series of sporadic cases to define the frequency and phenotypic correlates of epigenetic abnormalities in BWS. LOM at KvDMR1 was detected by Southern analysis or a novel PCR based method in 35 of 69 (51%) sporadic BWS without UPD. LOM at KvDMR1 was often, but not invariably associated with LOI of IGF2. KvDMR1 LOM was not detected in BWS patients with putative BWSIC1 defects and cases with KvDMR1 LOM (that is, putative BWSIC2 defects) invariably had a normal H19 methylation pattern. The incidence of exomphalos in putative BWSIC2 defect patients was not significantly different from that in patients with germline CDKN1C mutations (20/29 and 13/15 respectively), but was significantly greater than that in patients with putative BWSIC1 defects (0/5, p=0.007) and UPD (0/22, p<0.0001). These findings are consistent with the hypothesis that LOM of KvDMR1 (BWSIC2 defect) results in epigenetic silencing of CDKN1C and variable LOI of IGF2. BWS patients with embryonal tumours have UPD or a BWSIC1 defect but not LOM of KvDMR1. This study has further shown how (1) variations in phenotypic expression of BWS may be linked to specific molecular subgroups and (2) molecular analysis of BWS can provide insights into mechanisms of imprinting regulation.

The role of P-glycoprotein in determining the oral absorption and clearance of the NK2 antagonist, UK-224,671

UK-224,671 has been shown to exhibit low oral bioavailability in vivo due to poor absorption from the GI tract. The purpose of this study was to investigate the underlying reason for this observation. In Caco-2 cell flux experiments, the absorptive (A to B) flux of UK-224,671 was low, consistent with poor in vivo absorption. However, flux in the B to A direction was significantly greater, suggesting that UK-224,671 can permeate the membrane of the gut wall cell. Such a Caco-2 cell flux is indicative of transporter mediated efflux, possibly by P-glycoprotein. In P-glycoprotein knockout mice, the oral bioavailability of UK-224,671 was 22%, representing a significant increase over the P-glycoprotein expressing wild type mice (<2%). However, in the knockout mice absorption was still incomplete, suggesting that both P-glycoprotein mediated efflux and poor membrane permeation combine to limit the oral absorption of UK-224,671 in wild type mice. Lack of P-glycoprotein expression had no effect on the clearance of UK-224,671 in mice, which suggests that uptake from the blood into the excretory cell is mediated by a transporter other than P-glycoprotein. Bile duct cannulated rat experiments show that approximately 20% of the clearance of UK-224,671 occurs by direct secretion across the gut wall into the faeces. This clearance pathway requires UK-224,671 to cross both the basolateral and apical membranes of the gut wall cell. P-glycoprotein is likely to be involved in the passage of the compound across the apical membrane as has been observed for other P-glycoprotein substrates.

Methods for detecting age-related maculopathy: a comparison between photographic and clinical assessment

PURPOSE

To examine the sensitivity, specificity and overall agreement between photographic and clinical assessment in detecting age-related maculopathy (ARM) features in the context of an epidemiological study, the Vitamin E, Cataract and Age-related Maculopathy Study (VECAT).

METHODS

A total of 1204 volunteers aged between 55 and 80 years of age, who were enrolled in the VECAT Study, had both slit-lamp biomicroscopy examination and fundus photos taken as part of the baseline ophthalmic examination. The Nidek 3-DX fundus camera (Nidek, Gamagori, Japan) was used to produce paired, one-framed, coloured, 15 degrees stereoslides of the macular area at a fixed angle. An International Classification and Grading System for Age-related Maculopathy and Age-related Macular Degeneration was used to grade the stereoslides. Agreement in the detection of drusen, pigment abnormalities, and late stage ARM features was assessed using unweignted kappa statistic. Cases of disagreement were verified using clinical data records, grading documentation and the review of stereoslides.

RESULTS

Macula status was available for 2386 eyes. For drusen of size < 63 microm, sensitivity was 47%, specificity was 68% with a kappa value of 0.20. For drusden > or = 125 microm, sensitivity and specificity were > or =81%. Kappa values ranged from 0.56 to 0.71. Levels of agreement for pigment abnormalities and late ARM were in the substantial range (i.e. kappa values from 0.70 to 1.00).

CONCLUSIONS

Slit-lamp biomicroscopy was found to be comparable to photograding (using the Nidek 3-DX fundus camera) for detecting features pertaining to ARM. However, given the objectivity and permanency of stereoslides, photograding is still the more reliable and the preferred system of assessing ARM in the context of an epidemiological study.

Amino acid transport into cultured McCoy cells infected with Chlamydia trachomatis

Amino acid transport into McCoy cells infected with strains representative of the two major biovars of Chlamydia trachomatis has been studied to determine if uptake is increased during infection. Preliminary work suggested that the transport systems L, A/ASC (for neutral amino acid transport), N (for transport of Asn, Gln, and His) and y+ (for cationic amino acids) were present in McCoy cells. With lymphogranuloma venereum biovar strain 434, little difference in the influx of representative amino acids Trp, His, and Lys or the analogue 2-aminoisobutyric acid (AIB) was observed during infection. With trachoma biovar strain DK20, a small increase in the initial entry rate and equilibrium concentration of each amino acid was found. McCoy cells appear to have great capacity for concentrating amino acids, which might obviate the need for transport induction by chlamydiae under conditions favoring the growth of infectious organisms.

Pharmacokinetics and metabolism of a sulphamide NK2 antagonist in rat, dog and human

1. UK-224,671 is a sulphamide-containing NK2 antagonist with moderate lipophilicity and basicity. 2. The physicochemical properties of UK-224,671 are reflected in its pharmacokinetics following intravenous (i.v.) administration. The compound partitioned extensively into red blood cells in all species examined and the blood clearance was moderate to low with respect to liver blood flow and distribution into tissues was extensive. 3. UK-224,671 exhibited species differences in oral bioavailability. In dog, the compound exhibited moderate bioavailability (55%), whereas in rat and man oral bioavailability was < 10%. 4. In rat and dog, the major excreted form after i.v. administration was unchanged UK-224,671 in both urine and faeces. In addition, of three metabolites observed, the most abundant was the N-descyclopropylmethyl (UK-280,045). 5. The profile of radioactivity in rat following oral administration of [14C]-UK-224,671 was not consistent with a 10% absorbed compound with 40% of the dose present as metabolites. This suggests that the low bioavailability of UK-224,671 in rat is due to a combination of moderate intestinal permeability and extensive first-pass metabolism by the gut and does not result from poor gastrointestinal absorption per se.

Chlamydial development is adversely affected by minor changes in amino acid supply, blood plasma amino acid levels, and glucose deprivation

This study has demonstrated the extreme sensitivity of Chlamydia trachomatis growing in McCoy cells to small changes in external amino acid supply. In the absence of cycloheximide, a decrease in the amino acid concentration of medium to 75% of control values was sufficient to induce the growth of enlarged chlamydial forms of reduced infectivity. Morphology became more distorted and the yield of infectious particles from inclusions declined as medium amino acid levels were further reduced. These events correlated with a general decline in intracellular amino acids, as measured by high-performance liquid chromatography, suggesting that chlamydiae require a minimum concentration of each amino acid for normal development. Cycloheximide enhanced the production of normal organisms and increased infectivity yield in media, suggesting that the drug increased the available pool of amino acids. This was supported by intracellular amino acid analyses. Aberrant forms with reduced infectivity were also induced during supply of infected cell cultures with medium containing blood plasma amino acid concentrations, supporting the proposal that nutrient levels in vivo could promote abnormal chlamydial development. Markedly abnormal forms were also observed during glucose deprivation, providing further evidence that aberrant development is a general stress-related response.

Digital replantation teaching model in rats

Replant surgery is a complex procedure that requires advanced microsurgical skills and is usually performed as an emergency operation, lasting many hours. For these reasons, teaching replantation is difficult. Although teaching models exist, they are often too general or complicated for routine use and do not simulate the stages and the pitfalls of human replant surgery. We have designed a model that is simple and imitates human replant surgery. After reviewing the rat anatomy, students dissect and replant a rat hind limb that has been sharply amputated by the instructor. They follow the same principles of "real" surgery like debridement, minimizing ischemia time, and stable fixation before anatomosis of vessels. After marking the structures, bony fixation followed by vessel and nerve anastomosis are performed. Muscle is reattached to the skin and limb vascularity evaluated. After we designed this model, plastic surgery residents performed the technique on 10 rats. An 80% limb viability rate was achieved. This model is simple to perform, simulates all the relevant structures and pitfalls of human surgery, and the rats are relatively cheap and can be used for other parallel projects.

Learning curve of microvascular venous anastomosis: a never ending struggle?

In this study, a simple protocol based on the rat femoral venous anastomosis was established to provide a quantitative representation of the progress. The learning curve is based on the patency rate in each consecutive group of five anastomoses. Two groups of surgeons were observed. The inexperienced group encountered a tough time in the first 25 anastomoses. However, the progress was fast and is represented by the steep slope of the curve. A plateau was reached whereby the avearge patency rate matches that of the experienced group. As expected, there was no learning curve for the experienced group. Despite every effort to attempt to maintain a perfect 100% patency on this model, the best achievable patency was only 88%. The results and its implication are discussed.

The World Health Organization WHOQOL-100: tests of the universality of Quality of Life in 15 different cultural groups worldwide

The World Health Organization Quality of Life assessment (WHOQOL-100) was developed simultaneously across 15 international field centers and includes 24 facets relating to quality of life, which are grouped into 4 larger domains: physical, psychological, social relationships, and environment. It also includes 1 facet examining overall quality of life and general health perceptions. This article examines the extent to which the WHOQOL-100 assesses quality of life perceptions in different cultures and whether it is structurally comparable in these cultures. Regression analysis showed all 4 domains to be important in assessing quality of life in each of the 15 centers. Structural equation modeling suggested further support for the proposal that there are universal facets and domains that are cross-culturally important in determining quality of life and suggested that the ordering of facets within domains is comparable across cultures.

The World Health Organization WHOQOL-100: tests of the universality of Quality of Life in 15 different cultural groups worldwide

The World Health Organization Quality of Life assessment (WHOQOL-100) was developed simultaneously across 15 international field centers and includes 24 facets relating to quality of life, which are grouped into 4 larger domains: physical, psychological, social relationships, and environment. It also includes 1 facet examining overall quality of life and general health perceptions. This article examines the extent to which the WHOQOL-100 assesses quality of life perceptions in different cultures and whether it is structurally comparable in these cultures. Regression analysis showed all 4 domains to be important in assessing quality of life in each of the 15 centers. Structural equation modeling suggested further support for the proposal that there are universal facets and domains that are cross-culturally important in determining quality of life and suggested that the ordering of facets within domains is comparable across cultures.

Antioxidant effects of isoflavonoids and lignans, and protection against DNA oxidation

The antioxidant capability of a series of isoflavonoid and lignan compounds in both cellular and cell-free systems has been investigated, and related to structure. Nordihydroguaiaretic acid exhibited a potent antioxidant activity in both HepG2 and MDA-MB-468 cells (IC50 5.3 and 1.1 microM respectively), as determined by inhibition of 2',7'-dichlorofluorescin oxidation via t-BOOH, although no inhibition was observed with other compounds tested in this system. All compounds inhibited the formation of 8-oxodeoxyguanosine in DNA exposed to hydroxyl radicals via gamma irradiation or the Fenton reaction. Whilst almost complete inhibition of gamma irradiation-induced damage was achieved (IC50 ranged from 0.2 to 0.8 microM), inhibition was less pronounced with the Fenton system. The ability of all compounds to interact with DNA (as well as with reactive oxygen and iron) was also demonstrated by scanning UV spectroscopy, suggesting that the compounds may inhibit DNA oxidation at least in part by binding to DNA. Hydroxyl radical-scavenging, iron-chelating and DNA-binding activity of these compounds supports their proposed role as natural cancer-protective agents.

Structure of d(TGCGCA)2 and a comparison to other DNA hexamers

The X-ray crystal structure of d(TGCGCA)2 has been determined at 120 K to a resolution of 1.3 A. Hexamer duplexes, in the Z-DNA conformation, pack in an arrangement similar to the 'pure spermine form' [Egli et al. (1991). Biochemistry, 30, 11388-11402] but with significantly different cell dimensions. The phosphate backbone exists in two equally populated discrete conformations at one nucleotide step, around phosphate 11. The structure contains two ordered cobalt hexammine molecules which have roles in stabilization of both the Z-DNA conformation of the duplex and in crystal packing. A comparison of d(TGCGCA)2 with other Z-DNA hexamer structures available in the Nucleic Acid Database illustrates the elusive nature of crystal packing. A review of the interactions with the metal cations Na+, Mg2+ and Co3+ reveals a relatively small proportion of phosphate binding and that close contacts between metal ions are common. A prediction of the water structure is compared with the observed pattern in the reported structure.

The effect of transmission bandwidth on diagnostic accuracy in remote fetal ultrasound scanning

Six subspecialists with considerable experience in fetal ultrasound viewed a selection of pre-recorded ultrasound scans. Scans from 18 patients recorded on VHS video-tape were supplied from five centres in the UK and Ireland, each made on a high-resolution ultrasound machine by an experienced sonologist at a referral centre. Each observer viewed the scans on a large display monitor in an individual viewing booth. The scans were viewed in random order, at randomly selected bandwidths. Observers, who were blinded to both recording and bandwidth, assessed the technical quality on a five-point Likert scale. They also recorded their diagnosis. The six observers each carried out 32 viewing sessions, which gave a total of 192 viewings. There was no significant difference in the perceived technical quality of the scans between the two bandwidths used (P = 0.09). Of the 84 recordings transmitted at 1920 kbit/s, 71 (85%) were diagnosed correctly or 'half correctly' and 13 (15%) were misdiagnosed. Of the 95 recordings transmitted at 384 kbit/s, 66 (69%) were diagnosed correctly or 'half correctly' and 29 (31%) were misdiagnosed. This difference was significant (P = 0.03). The results indicate that although there were no perceived differences in technical quality between recordings transmitted at 384 or 1920 kbit/s, diagnostic accuracy was marginally worse at the lower bandwidth. This suggests that the higher bandwidth conveys more detail and information to the observer, which in turn enables more accurate diagnosis. However, further work is required before a definitive choice can be made about the optimum transmission bandwidth for remote fetal ultrasound studies.

Ictal cerebral perfusion related to EEG in drug resistant focal epilepsy of childhood

OBJECTIVES

To evaluate the EEG changes during seizures in children with drug resistant focal epilepsy who demonstrate hypoperfusion at the "seizure focus" interictally, but no perfusion change during the seizure.

METHODS

Ictal EEG findings of six children with focal epilepsy who demonstrated hypoperfusion on rCBF SPECT after an interictal injection of (99)Tc(m) HMPAO concordant with the seizure focus, but who did not demonstrate rCBF change after an ictal injection (group 1) were reviewed. These were contrasted with the EEG data of six children matched as closely as possible for age, type of epilepsy, and pathology who did show hyperperfusion at the seizure focus on ictal scan when compared with the interictal study (group 2).

RESULTS

The children in group 1 showed slowing of the EEG at the time of the (99)Tc(m) HMPAO injection relative to that seen at the onset of the seizure. Those in group 2 showed rhythmic activity, or sharp waves, or both on EEG at the time of injection. This last change was also seen consistently when the EEG data of a further 13 children who also showed ictal hyperperfusion at the seizure focus were reviewed.

CONCLUSION

Ictal rCBF does not invariably increase at the seizure focus in patients with drug resistant focal epilepsy.

Evaluation of beta-globin gene therapy constructs in single copy transgenic mice

Effective gene therapy constructs based on retrovirus or adeno-associated virus vectors will require regulatory elements that direct expression of genes transduced at single copy. Most beta-globin constructs designed for therapy of beta-thalassemias are regulated by the 5'HS2 component of the locus control region (LCR). Here we show that a human beta-globin gene flanked by two small 5'HS2 core elements or flanked by a 5'HS3 (footprints 1-3) core and a 5'HS2 core are not reproducibly expressed in single copy transgenic mice. In addition, low copy transgene concatamers that contain only dimer 5'HS2 cores fail to express, whereas those that contain monomer 5'HS2 cores express at 14% per copy. These data suggest that spacing between HS cores is crucial for LCR activity. We therefore constructed a novel 3.0 kb LCR cassette in which the 5'HS2, 5'HS3 and 5'HS4 cores are each separated by approximately 700 bp. When linked to the 815 bp beta-globin promoter this LCR directs 45% levels of expression from four independent single copy transgenes. However, the 3.0 kb LCR linked to the 265 bp promoter expresses variable levels, averaging 18%, from three single copy transgenes. Our findings suggest that sequences in the distal promoter play a role in single copy transgene activation and that larger LCR and promoter elements are most suitable for gene therapy applications.

The p53 response to ionising radiation in adult and developing murine tissues

The induction of the p53 response to ionising radiation has been studied during murine development and in the adult animal. The response has been assessed by precise quantitative assay of p53 protein levels in tissues and by immunohistochemistry. Newly developed transgenic mice in which a lacZ transgene is driven by a p53 response element have also been used to directly assess the transcriptional activity of the induced protein. There is striking developmental control of the p53 response so that in early development all tissues accumulate high levels of p53 following radiation and indeed p53 is present at elevated levels in some unirradiated tissues. Later in development clear heterogeneity of the p53 response becomes apparent, both in terms of the responses of individual tissues and of cell populations, within those tissues. The study of lacZ transgene expression and the occurrence of apoptosis in different tissues that accumulate p53 protein point to a further level of control regulating the nature and degree of the downstream response to elevated levels of p53 in cells. These findings have important implications for the susceptibility of different tissue types to carcinogenic and other insults. The early expression of the p53 response is consistent with novel models of p53 function that suggest it may have evolved principally as a defense against teratogenic insult that permits plasticity of development.

The human beta-globin locus control region confers an early embryonic erythroid-specific expression pattern to a basic promoter driving the bacterial lacZ gene

The beta-globin locus control region (LCR) is contained on a 20 kb DNA fragment and is characterized by the presence of five DNaseI hypersensitive sites in erythroid cells, termed 5′HS1-5. A fully active 6.5 kb version of the LCR, called the muLCR, has been described. Expression of the beta-like globin genes is absolutely dependent on the presence of the LCR. The developmental expression pattern of the genes in the cluster is achieved through competition of the promoters for the activating function of the LCR. Transgenic mice experiments suggest that subtle changes in the transcription factor environment lead to the successive silencing of the embryonic epsilon-globin and fetal gamma-globin promoters, resulting in the almost exclusive transcription of the beta-globin gene in adult erythropoiesis. In this paper, we have asked the question whether the LCR and its individual hypersensitive sites 5′HS1-4 can activate a basic promoter in the absence of any other globin sequences. We have employed a minimal promoter derived from the mouse Hsp68 gene driving the bacterial beta-galactosidase (lacZ) gene. The results show that the muLCR and 5′HS3 direct erythroid-specific, embryonic expression of this construct, while 5′HS1, 5′HS2 and 5′HS4 are inactive at any stage of development. Expression of the muLCR and 5′HS3 transgenes is repressed during fetal stages of development. The transgenes are in an inactive chromatin conformation and the lacZ gene is not transcribed, as shown by in situ hybridization. These data are compatible with the hypothesis that the LCR requires the presence of an active promoter to adopt an open chromatin conformation and with models proposing progressive heterochromatization during embryogenesis. The results suggest that the presence of a beta-globin gene is required for LCR function as conditions become more stringent during development.

Exon 1 of the HD gene with an expanded CAG repeat is sufficient to cause a progressive neurological phenotype in transgenic mice

Huntington's disease (HD) is one of an increasing number of neurodegenerative disorders caused by a CAG/polyglutamine repeat expansion. Mice have been generated that are transgenic for the 5' end of the human HD gene carrying (CAG)115-(CAG)150 repeat expansions. In three lines, the transgene is ubiquitously expressed at both mRNA and protein level. Transgenic mice exhibit a progressive neurological phenotype that exhibits many of the features of HD, including choreiform-like movements, involuntary stereotypic movements, tremor, and epileptic seizures, as well as nonmovement disorder components. This transgenic model will greatly assist in an eventual understanding of the molecular pathology of HD and may open the way to the testing of intervention strategies.

A dominant chromatin-opening activity in 5' hypersensitive site 3 of the human beta-globin locus control region

Single-copy human beta-globin transgenes are very susceptible to suppression by position effects of surrounding closed chromatin. However, these position effects are overcome by a 20 kbp DNA fragment containing the locus control region (LCR). Here we show that the 6.5 kbp microlocus LCR cassette reproducibly directs full expression from independent single-copy beta-globin transgenes. By testing individual DNase I-hypersensitive sites (HS) present in the microlocus cassette, we demonstrate that the 1.5 kbp 5'HS2 enhancer fragment does not direct beta-globin expression from single-copy transgenes. In contrast, the 1.9 kbp 5'HS3 fragment directs beta-globin expression in five independent single-copy transgenic mouse lines. Moreover, the 5'HS3 core element and beta-globin proximal promoter sequences are DNase I hypersensitive in fetal liver nuclei of these expressing transgenic lines. Taken together, these results demonstrate that LCR activity is the culmination of at least two separable functions including: (i) a novel activity located in 5'HS3 that dominantly opens and remodels chromatin structure; and (ii) a recessive enhancer activity residing in 5'HS2. We postulate that the different elements of the LCR form a 'holocomplex' that interacts with the individual globin genes.

Immunocytochemical localization of aspartate and glutamate in the peripheral vestibular system

Controversy exists concerning the identity of the neurotransmitter in the mammalian peripheral vestibular system. Several candidates have been proposed, including the excitatory amino acids glutamate and aspartate and the inhibitory amino acid gamma-aminobutyric acid (GABA). Previous studies have demonstrated vestibuloneural electrophysiological activity associated with glutamate and aspartate. Paraffin sections of rat vestibular ganglia and end-organs were examined for the presence of glutamate-like and aspartate-like immunoreactivity. Our results demonstrate the presence of both aspartate-like and glutamate-like immunoreactivity in vestibular hair cells, peripheral vestibular nerve fibers, and vestibular ganglion cells. Minimal immunoreactivity was noted in the tissues surrounding these cells. These data add support to the hypothesis that the excitatory amino acids glutamate and aspartate are involved in vestibular neurotransmission.

Patterns of visual loss associated with pituitary macroadenomas

PURPOSE

To describe the patterns of visual loss associated with pituitary macroadenomas compressing the anterior visual pathway.

METHOD

A prospective survey of 29 patients with pituitary macroadenomas who presented to the neurosurgical unit at St Vincent's Hospital, Melbourne. Selected patients had histologically verified pituitary macroadenomas, and visual defects (acuity, colour and/or field loss) consistent with anterior visual pathway compression.

RESULTS

All patients had visual field defects detected on perimetry, and the majority were asymmetrical. Bitemporal defects were most common but field defects ranged from monocular defects to generalised constriction. Four patients (13.8%) did not report visual symptoms, and of those who had symptoms, blurred vision was the most common complaint. Ninety-six per cent of eyes had field loss, 56% had decreased colour vision, 46% had decreased acuity, 31% had optic disc pallor, and 2% had an ophthalmoplegia.

CONCLUSIONS

Patients with visual pathway compression by pituitary macroadenomas may be asymptomatic despite having field defects. Perimetry is the most sensitive method of identifying compression, followed by colour vision, visual acuity, then the presence of optic atrophy. Automated static threshold perimetry appears to show early field defects better than manual kinetic perimetry. All patients with pituitary macroadenomas should have thorough ophthalmological examinations, including perimetry to document visual deficits secondary to compression.

Menorrhagia management options

A prospective study of the management of menorrhagia in new patients presenting to gynaecological outpatients was undertaken at four centres in Northern Ireland and two in Great Britain. 325 patients were enrolled, the majority of whom (87%) had severe menorrhagia. Patients in all six centres were similar in relation to age, marital status, parity, use of contraception and severity of symptoms. 62% of the patients were managed medically, improved and were discharged. The rates of surgical intervention, in particular in women aged less than 40, appeared higher in the Northern Ireland hospitals than Great Britain. There is a need to review and audit current practices in the management of menorrhagia.

The effect of temperature on spontaneous action potential discharge of the isolated sinus venosus from winter and summer plaice (Pleuronectes platessa)

The spontaneous cardiac pacemaker activity and conformation were recorded in vitro, using intracellular recording methods, from heart tissue of summer- and winter-caught plaice. The effects of changing temperature on the pacemaker rate, duration of action potential and diastolic depolarization were investigated by altering the temperature of the superfusing medium. The resting intrinsic rate of discharge was significantly greater in pacemaker cells from winter plaice (P=0.05), but there was no significant difference between winter and summer fish in the apparent Arrhenius activation energies for this process. However, there was a significant difference in the estimated intercept, indicating a thermal shift in the processes underlying the spontaneous pacemaker rhythm. There was no significant difference in the diastolic depolarization duration recorded from winter and summer fish over the temperature range 4&shy;22 &deg;C. The major effect of previous environmental temperature was on the duration of the action potential (P&lt;0.02), indicating that the observed changes in pacemaker discharge rate were not influenced by the processes that determine the duration of the pacemaker diastolic depolarisation but were modulated by the channel events that give rise to the action potential.

Nitric oxide in the rat vestibular system

Nitric oxide is known to function as a neurotransmitter in the central nervous system. It is also known to be involved in the central nervous system excitatory amino acid neurotransmission cascade. Activation of excitatory amino acid receptors causes an influx of calcium, which activates nitric oxide synthase. The resulting increase in intracellular nitric oxide activates soluble guanylate cyclase, leading to a rise in cyclic guanosine monophosphate. The excitatory amino acids glutamate and aspartate are found in the vestibular system and have been postulated to function as vestibular system neurotransmitters. Although nitric oxide has been investigated as a neurotransmitter in other tissues, no published studies have examined the role of nitric oxide in the vestibular system. Neuronal NADPH-diaphorase has been characterized as a nitric oxide synthase. This enzyme catalyzes the conversion of L-arginine to L-citrulline, producing nitric oxide during the reaction. We used a histochemical stain characterized by Hope et al. (Proc Natl Acad Sci 1991;88:2811) as specific for neuronal nitric oxide synthase to localize the enzyme in the rat vestibular system. An immunocytochemical stain was used to examine rat inner ear tissue for the presence of the enzyme's end product, L-citrulline, thereby demonstrating nitric oxide synthase activity. Staining of vestibular ganglion sections showed nitric oxide synthase presence and activity in ganglion cells and nerve fibers. These results indicate the presence of active nitric oxide synthase in these tissues and suggest modulation of vestibular neurotransmission by nitric oxide.

Managed care is in your future

Though Texas has been slower than most other large states to move into managed care, it is gaining ground. According to the Texas Health Maintenance Organization Association, 1.2 million Texans were enrolled in HMO plans in January 1990. Three years later, 1.5 million had signed on--a 24 percent increase. State enrollment in other managed care plans, which aren't required to file reports with state regulatory agencies, was estimated to be 6.9 million (41 percent of Texans) in 1991, according to Blue Cross/Blue Shield. While these state enrollment figures are large, the most recent numbers available indicate that Texas hospitals have a long way to go. A 1991 AHA survey found that 259 Texas hospitals (47 percent of those surveyed) do not have contracts with HMOs or PPOs. With changes coming at break-neck speed, how can these hospitals position themselves to survive and prosper in the managed care world? This month, HealthTexas presents three examples of hospitals and health care systems that have successfully made the transition to managed care. Their stories illustrate three very different approaches--developing a network, direct contracting, and establishing a health plan. And, those who have led these ventures offer advice to help other hospitals make the transition a little easier.

Primary team nursing: the 90s model

The nursing shortage of the late 80s necessitated development of an alternative to primary nursing to meet patient needs. After assessing the strengths and limitations of functional nursing, team nursing and primary nursing, a team designed a new model which incorporated the best features of the three. After a pilot period, "primary team nursing" has proven effective and feedback from nurses has been positive.

Foamy changes of placental cells in probable beta glucuronidase deficiency associated with hydrops fetalis

Mucopolysaccharidosis type VII (MPS VII, beta glucuronidase deficiency) has been described in association with non-immune hydrops fetalis. Three consecutive pregnancies in an itinerant family, which resulted in stillbirths caused by non-immune hydrops are described. The parents were closely related and there was a strong family history of storage disorders. The main clue to the diagnosis, however, came from the presence of pronounced foamy cytoplasmic change in the villous Hofbauer cells of the placenta. This raised the possibility of an inherited metabolic storage disorder. The parents were subsequently shown to have beta glucuronidase activities in the heterozygous range in leucocytes and fibroblasts which suggested that the non-immune hydrops was caused by beta glucuronidase deficiency.

Low-nutrient induction of abnormal chlamydial development: a novel component of chlamydial pathogenesis?

The intracellular development of chlamydiae in McCoy cells incubated in Eagle's minimal essential medium lacking all 13 amino acids was examined both by fluorescence and electron microscopy and by infectivity titration. Aberrant development occurred in almost all inclusions of strains of Chlamydia trachomatis and C. psittaci with the production of abnormal forms which differed in size, shape and internal structure from normal reticulate and elementary body forms. Detailed analysis of the response of C. trachomatis L2 strain 434 to graded reductions in amino acid level showed that infectivity was reduced and morphological abnormality increased as amino acid concentrations were lowered from 33 to 0% of amino acids present in minimal essential medium. Reversion of inclusions to normal and reappearance of infectious forms occurred on restoration of amino acids and further incubation. It is suggested that aberrant development may account for the presence in vivo of non-cultivable chlamydiae and that such development can arise via tryptophan deprivation mediated by local release of interferon gamma.

Follow-up of children born to hypertensive mothers

Maternal hypertension has significant adverse effects on perinatal outcome. We aimed to assess whether there are long-term effects on growth and neurodevelopment in childhood. Thirty-seven children were reviewed at a median age of 56 months. Although maternal hypertension had had a significant impact on perinatal outcome of these children, most had normal growth and development in childhood. The severity of maternal hypertension was influential on perinatal outcome, but not on long-term outcome.

Long term predictive value of Doppler studies in high risk fetuses

OBJECTIVE

To determine whether the predictive value of Doppler ultrasonography extends beyond the perinatal period.

DESIGN

Descriptive follow-up study.

SETTING

Specially designated paediatric clinic in Royal Maternity Hospital.

SUBJECTS

40 children who as high risk fetuses had had assessment of umbilical artery flow velocity waveforms.

INTERVENTIONS

Parental history, physical examination, anthropometry, Denver developmental screening test.

OUTCOME MEASURES

Weight, height, head circumference, neurological impairment, Denver development screening test

RESULT

Abnormal waveforms were an accurate predictor of neonatal outcome, with significant differences in birthweight, gestational age, need for nursery admission, and frequency of intrauterine growth retardation between normal and abnormal waveform groups. However, abnormal Doppler studies were not predictive of long-term adverse sequelae. There were no significant differences in height, head circumference, proportion with neurological impairment, or results of Denver developmental screening test at a median age of five years.

CONCLUSION

The predictive value of Doppler ultrasonography is less for long-term growth and neurodevelopment than for perinatal outcome in the high risk fetus.

Prenatal diagnosis of cystic adenomatoid malformation of the lung in a twin pregnancy

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Laser-assisted venous anastomosis: a comparison study

A low-powered carbon dioxide laser was used to perform 25 vein grafts (50 anastomoses) on the femoral veins of Sprague-Dawley rats. The patency rate, clamp time, and bleeding time were compared with 50 conventional microvascular vein grafts (100 anastomoses). The patency of the laser-assisted anastomoses (LAVA) was 84 percent, while the conventional vein grafts yielded a 94 percent patency rate. The average clamp time and bleeding time for the LAVA were 47.2 min and 4.88 sec, respectively, while the conventional anastomoses required 57.6 min and had an average bleeding time of 9.44 sec. Histologically, both specimens healed at the same rate, but the laser-assisted anastomoses produced less inflammation and granulation tissue. These results suggest that the laser has potential as a tool for clinical application in microsurgery. In addition, the 94 percent patency rate achieved with the vein interposition graft would suggest that a decrease in the tension across the anastomosis can improve patency.

Maternal and fetal haemodynamics in hypertensive pregnancies during maternal treatment with intravenous hydralazine or labetalol

Intravenous treatment with 10 mg of hydralazine or 100 mg of labetalol was randomly allocated to 30 hypertensive pregnant women. Umbilical artery flow velocity waveforms were recorded using a pulsed Doppler duplex scanner (ATL Mk V) and umbilical artery pulsatility index (PI) and fetal heart rate (FHR) were derived from these recordings. Maternal blood pressure decreased significantly after both drugs. Maternal pulse rate increased after hydralazine but did not change significantly after labetalol. FHR did not change significantly after hydralazine but decreased after labetalol. PI decreased after hydralazine and increased after labetalol--most fetuses showed little change but a few in each group showed large changes in PI, as did two of five additional patients studied. We attributed the decrease in PI in some fetuses after hydralazine to vasodilation, and the increase in PI in some fetuses after labetalol to vasoconstriction in the fetoplacental circulation, suggesting that fetal beta-blockade may occur after maternal treatment with labetalol.

Association of dry eye signs and symptoms with tear lactoferrin concentration

Diagnoses of dry eye made with the Lactoplate Immunoassay Test (which assesses tear lactoferrin concentration) were compared to diagnoses based on dry eye symptoms, tear break-up times, and rose bengal staining. For a population of 49 subjects with normal and mild to moderate dry eyes, contingency tables showed that the lactoferrin-based diagnoses were not significantly related to the diagnoses made using any of the other factors. Lactoferrin concentrations were statistically correlated with symptom scores, but there was no significant correlation between lactoferrin concentrations and either tear break-up time or rose bengal staining. These results suggest that: 1) the dry eye problems in the subject population may not have been associated with lacrimal gland dysfunction (which the Lactoplate assesses); 2) Lactoplate tests are not sensitive enough to allow accurate diagnoses for the population of mild to moderate dry eye subjects used; 3) signs and symptoms associated with dry eyes occur before lactoferrin changes are manifest so lactoferrin changes had not yet appeared in the subjects; or 4) in mild to moderate dry eye subjects, lactoferrin changes occur only in reflexive tears and not in the basal tears that were tested in this study. In summary, measurement of tear lactoferrin concentration alone has not been shown to be a sufficiently sensitive and specific test for the diagnosis of mild to moderately dry eye as defined by more common clinical techniques.