Clinicopathological features of equine primary hepatic disease: a review of 50 cases

The clinicopathological features of 50 cases of equine hepatic disease were reviewed. There was a wide range of clinical signs and at least 50 per cent of the animals exhibited either dull demeanour, anorexia, abdominal pain, cerebral dysfunction and/or weight loss. Life-threatening complications of hepatic failure recorded were: gastric impaction in 10 cases, bilateral laryngeal paralysis in seven cases and coagulopathy in five cases. All the cases had high activities of gamma-glutamyl transferase (GGT) and most had high activities of glutamate dehydrogenase (GLDH) and high concentrations of bile acids. Fewer of the horses had abnormal concentrations of bilirubin, albumin and globulin. The horses that were euthanased or died had significantly higher concentrations of GGT, GLDH and bile acids than the survivors. There were biochemical data for 18 cases with signs of hepatic encephalopathy, all of them had plasma ammonia levels greater than 90 micromol/litre but this was not significantly correlated with the clinical severity of the condition. Half of the cases with hepatic encephalopathy were hyperglycaemic, none was hypoglycaemic, and none had abnormally low levels of plasma urea.

Situs revisited: imaging of the heterotaxy syndrome

Situs anomalies present a diagnostic challenge to radiologists because of the overlapping spectrum of findings commonly seen in asplenia and polysplenia. In a series of 21 patients with a diagnosis of heterotaxy syndrome, all 11 asplenic patients and seven of 10 polysplenic patients had congenital heart disease. Although there was a variety of complex congenital heart disease, the most common type in both patient groups was a common atrioventricular canal. In both groups, the laterality of the aorta and stomach was quite variable, but intestinal malrotation was a constant feature. In 11 asplenic patients, the most frequent findings were a bridging liver (10 cases), absent spleen (10 cases), and left-sided inferior vena cava (nine cases). Only seven of these patients had an aorta ipsilateral to the inferior vena cava, contrary to previous thought that this finding was specific for asplenia. In the 10 polysplenic patients, bridging livers were less frequent (five cases), single (six cases) or multiple (four cases) spleens were seen, and azygous continuation with interruption of the inferior vena cava was usually present (eight cases). Although not pathognomonic of polysplenia, inferior vena cava interruption with azygous or hemiazygous continuation is the most common anatomic finding of this condition. Although the terms asplenia and polysplenia are helpful in suggesting the typical anatomy, both syndromes encompass an overlapping spectrum that needs to be described individually and may best be called heterotaxy syndrome.

Novel approaches for discovering industrial enzymes

New technologies for enzyme discovery are changing the rules of the game for industrial biocatalysis. More kinds of enzymes are available, their hardiness is increasing, and their costs are coming down. These changes are the key drivers for a rebirth of interest in industrial applications of enzymes. The major enabling discovery approaches include screening of biodiversity, genomic sequencing, directed evolution and phage display.

Efficacy of spinal cord stimulation for neuropathic pain following idiopathic acute transverse myelitis: a case report

Spinal cord stimulation (SCS) involves the electrical stimulation of dorsal structures within the spinal cord, and is the most widespread application of neurostimulation for the relief of chronic pain. Idiopathic acute transverse myelitis (IATM) is an acute monophasic lesion of the spinal cord that presents with symptoms associated with loss of cord function. The incidence of chronic pain secondary to this condition is unknown, but is considered rare. We report the efficacy of SCS for relief of severe neuropathic pain in both lower limbs secondary to IATM, which had failed to respond to conventional pain therapies.

A comparison of epidural ropivacaine infusion alone and in combination with 1, 2, and 4 microg/mL fentanyl for seventy-two hours of postoperative analgesia after major abdominal surgery

Our aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness and side effects of epidural infusions with ropivacaine 2 mg/mL alone (Group R; n = 60) and in combination with fentanyl 1 microg/mL (R1F; n = 59), 2 microg/mL (R2F; n = 62), and 4 microg/mL (R4F; n = 63) for up to 72 h after major abdominal surgery. Effective epidural neural blockade was established before surgery; postoperatively, the infusion rate was titrated to a maximum of 14 mL/h for analgesia. No additional analgesics other than acetaminophen were permitted during the infusion. The median of individual visual analog scale score with coughing were <20 mm for all groups (0 = no pain, 100 = worst pain) and was significantly lower (P < 0.01) for Group R4F at rest and with coughing (compared with Group R). Infusions were discontinued due to inability to control pain in significantly fewer patients in Group R4F (16%) than the other groups (34% to 39%; P < 0.01). For all groups, >90% of patients had no detectable motor block after 24 h. Hypotension, nausea, and pruritus were more common with the larger dose of fentanyl. We conclude that, after major abdominal surgery, an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL provided significantly more effective pain relief over a 3-day period than ropivacaine alone or ropivacaine with lower concentrations of fentanyl.

IMPLICATIONS

Postoperative epidural analgesic infusions are widely used, but there is little information regarding optimal strengths of opioid with local anesthetic. In this blinded, prospective study, we compared four different epidural infusion solutions for efficacy and side effects over a clinically useful postoperative period and conclude that an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL was most effective.

Regulation of the synthesis and secretion of vasopressin

We have developed a transgenic system that, for the first time, facilitates the monitoring of the regulatory dynamics of a central peptidergic system from transcription of a neuropeptide gene to the storage and release of the mature secretory product. Here we describe novel studies on the regulation of this system by physiological stimuli. The rat hypothalamic vasopressin (VP) mRNA responds in two ways to the functional demand imposed by an osmotic challenge. Firstly, the abundance of the VP RNA increases, and secondly, the size of the VP transcript increases as a consequence of a lengthening of the poly(A) tail. We have previously shown that chronic ingestion of 6-n-propyl-2-thiouracil (PTU), while not affecting plasma osmolality or VP mRNA size, results in a significant increase in the abundance of the hypothalamic VP mRNA. We now show that chronic PTU ingestion results in a dramatic increase in the abundance of the mRNA encoded by a modified rat vasopressin transgene that is expressed in rat vasopressinergic magnocellular neurons. This is accompanied by a significant depletion in neural lobe stores of a VP. However, this increase in transgene expression is accompanied by an increase in the proportion of transgene encoded products reaching the neural lobe--the pituitary content of a unique peptide encoded by the modified transgene does not change. These observations are further evidence in support of models of neurohypophyseal homeostasis that suggest that pituitary VP peptide levels passively reflect changes in hormone release and synthesis and that the availability of mRNA is the primary determinant of pituitary VP content in the basal state.

No coding variant of the tryptophan hydroxylase gene detected in seasonal affective disorder, obsessive-compulsive disorder, anorexia nervosa, and alcoholism

BACKGROUND

The goal of this study was to evaluate the role of genetic variation in the coding sequence of tryptophan hydroxylase (TPH) in the pathogenesis of several psychiatric diseases in which altered serotonin function has been implicated: bipolar affective disorder (BP), obsessive-compulsive disorder (OCD), anorexia nervosa (AN), seasonal affective disorder (SAD), panic disorder (PD), and alcoholism (Alc).

METHODS

Ninety-three percent of the TPH coding sequence was screened by polymerase chain reaction single-strand conformation polymorphism (SSCP) for DNA sequence variations in 128 AN, 88 OCD, 72 SAD, 45 PD, and 36 BP patients and 142 normal volunteers. Also included in the screening were 61 Alc randomly selected from a Finnish alcoholic population in which an association of a TPH intron 7 polymorphism with suicidality was previously observed. Polymorphisms detected by SSCP were characterized by DNA sequencing and by allele-specific restriction enzyme digestion. Genotyping was then performed in 34 Finnish alcoholic suicide attempters.

RESULTS

A rare silent mutation was identified in exon 10 and is designated T1095C. The C1095 allele was found in 1 OCD and in 2 AN subjects; all 3 individuals were heterozygous (C1095/T1095) for the variant allele. No association was observed between this TPH T1095C variant with either OCD, AN, Alc, or suicidality.

CONCLUSION

These results suggest that the coding sequence of the TPH gene does not contain abundant variants, and may not play a major role in vulnerability to several psychopathologies in which reduced serotonin turnover has been implicated.

Long-term outcomes of treatment of hyperthyroidism in Ireland

We investigated the long-term outcome of treatment in 159 patients with hyperthyroidism first seen between 1979 and 1992. Median duration of follow-up was 10 1/2 years. We also inquired into current practice for the follow-up of hyperthyroidism by other endocrinologists in Ireland. Seven cases of unrecognised hyperthyroidism (4 per cent) and one of unrecognised hypothyroidism were identified. Among patients with Graves' disease, of those treated with an antithyroid drug, 28 per cent were in remission, 68 per cent had relapsed and 4 per cent had become hypothyroid. Of those treated by sub-total thyroidectomy, 31 per cent were in remission, 19 per cent had relapsed, 19 per cent were hypothyroid and 31 per cent were sub-clinically hypothyroid. Among patients treated with radioiodine, 19 per cent were euthyroid, 3 per cent were still hyperthyroid and three-quarters had become hypothyroid. In contrast, after radioiodine for toxic nodular goitre, 63 per cent were euthyroid and only 32 per cent had become hypothyroid (Chi Squared v. Graves' disease, P = 0.001). Of 73 patients receiving thyroxine replacement, plasma TSH was normal in only 41 per cent, although 82 per cent of patients had been seen by the family doctor within the previous 12 months. Seven of 17 other endocrinologists undertook long-term follow-up of hyperthyroid patients in their specialist clinics but none was using a computerised system to co-ordinate this. The findings confirm that careful follow-up is required for all hyperthyroid patients. The family doctor is well positioned to undertake this, but education and auditing are required.

Something fishy in the rat brain: molecular genetics of the hypothalamo-neurohypophysial system

The brain peptides vasopressin and oxytocin play crucial roles in the regulation of salt and water balance. The genes encoding these neurohormones are regulated by cell-specific and physiological cues, but the molecular mechanisms remain obscure. New strategies, involving the introduction of rat transgenes into rats, are being used to address these issues, but the complexity of the rat genome has hampered progress. By contrast, the pufferfish, Fugu rubripes, has a "junk-free" genome. The oxytocin homologue from Fugu, isotocin, has been introduced into rats and is expressed in oxytocin neurons, where it is upregulated by physiological perturbations that upregulate the oxytocin gene. The Fugu and rat lineages separated 400 million years ago, yet the mechanisms that regulate the isotocin and oxytocin genes have been conserved. Fugu genome analysis and transgenesis in the physiologically tractable rat host are a powerful combination that will enable the identification of fundamental components of the neural systems that control homeostasis.

Lower intensity physical activity is advantageous for fat distribution and blood glucose among viscerally obese older adults

OBJECTIVE

The influence of daily accumulated physical activity on blood glucose among older adults with varying obesity patterns is unknown. The purpose of this investigation was to determine if the blood glucose lowering effect of daily movement is modulated by distribution of adiposity in a community-based sample of older persons.

METHODS

The study sample (N = 743) was mostly women (79.4%) with an average age of 74.5+/-0.3 yr. A question from the Yale Physical Activity Survey was the indicator of lower intensity physical activity. The response, answered in h x d(-1) spent in motion, was divided into tertiles (<3, 3 to <5, and > or = 5 h x d(-1)). Random blood glucose and total blood cholesterol were assessed via finger stick. The body mass index (BMI) and waist circumference (WC) delineated the categories of adiposity patterning as follows: nonobese (N = 354), BMI = 23.8+/-0.1 kg x m(-2) and WC = 80.3+/-0.4 cm; noncentral obese (N = 79), BMI = 30.8+/-0.1 kg x m(-2) and WC = 87.5+/-0.4 cm; and central obese (N = 310), BMI = 32.7+/-0.3 kg x m(-2) and WC = 103.3+/-0.5 cm.

RESULTS

After adjusting for age, gender, race, medication use, and postprandial state, blood glucose levels were lower with greater amounts of reported daily movement in the centrally obese, 8.6+/-0.4 mmol x L(-1), 6.6+/-0.4 mmol x L(-1), and 6.3+/-0.4 mmol x L(-1) for <3 h x d(-1), 3 to <5 h x d(-1), and > or = 5 h x d(-1), respectively (P < 0.001). As the centrally obese increased their hours of moving about, their WC was observed to be less, 105.7+/-0.8 cm, 103.4+/-0.8 cm, and 102.9+/-1.0 cm, respectively, independent of age, gender, race, and medication use (P < 0.05). Neither blood glucose nor WC differed between categories of daily movement in the noncentral obese or nonobese.

CONCLUSIONS

Our findings suggest that daily accumulated, lower intensity physical activity is advantageous for abdominal fat distribution and blood glucose among viscerally obese older adults.

Breath hydrogen measurement in ponies: a preliminary study

The aim of this study was to establish the normal patterns of breath hydrogen excretion in adult ponies following either voluntary consumption or administration per stomach tube of a test meal/carbohydrate substrate. After an overnight fast, the ponies (n = 7) received either no test meal (ie fasted), glucose, xylose, lactose, lactulose, wheat flour or oats. Exhaled breath samples were collected in duplicate at 0 minutes and at 30-minute intervals thereafter for eight hours. Analysis of duplicate breath hydrogen measurements (n = 714) indicated that the breath hydrogen collection/storage method was reliable. Fasting resulted in negligible levels of breath hydrogen excretion. Increases in breath hydrogen concentration greater than 10 ppm, sustained for at least 30 minutes, were regarded as being biologically significantly different than fasting data and were observed for all ponies following the ingestion of oats or the administration of wheat flour, for three ponies following the administration of glucose and xylose and for two ponies following the administration of lactulose and lactose. The pattern of breath hydrogen excretion was subject to variation between animals following the ingestion of identical test meals. This study provides evidence of incomplete glucose absorption in healthy ponies and indicates that ingestion of non-absorbable carbohydrates do not always result in hydrogen excretion.

Switching transgene expression in the brain using an adenoviral tetracycline-regulatable system

We have developed a tetracycline-regulatable adenoviral transfection system that mediates efficient long-term transfer of genes into neuronal cells in vivo. This system allows gene expression to be switched on, then off, and back on again simply by administering or removing doxycycline from the animals' drinking water. This regulatable adenoviral vector system should be of value in behavioral studies and in vivo studies of neuronal gene function, and may further the development of effective gene therapy strategies in the brain.

Costs of implementing a tuberculosis control plan: a complete education module that uses a train-the-trainer concept

BACKGROUND

Tuberculosis once was thought to be nearly eradicated, but there was a 14% increase in cases of tuberculosis between 1985 and 1993, although decreases were observed in both 1994 and 1995. To reduce spread of this disease, health care workers must be familiar with tuberculosis, its signs, symptoms, and modes of transmission. In October 1994 the Centers for Disease Control and Prevention issued "Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health Care Facilities." The combination of persistently high tuberculosis case rates, the development of multidrug-resistant tuberculosis, the new Centers for Disease Control and Prevention recommendations, and Occupational Safety and Health Administration enforcement has mandated large-scale training in health care facilities.

METHODS

A tuberculosis control plan was developed and the train-the-trainer concept was selected after review of the hospital's tuberculosis risk assessment, staff members requiring training, and available teaching staff. The training program that was developed included tuberculosis pathology and transmission, national and local epidemiology, placement and evaluation of skin tests, and an algorithm to assist in determining when isolation is indicated.

RESULTS

One hundred forty-six trainers were trained in 4 days. During the next quarter, 66% (1989/3000) of staff members requiring instruction were trained. The total cost involved in development and training was approximately $26,000 and involved 1600 person-hours.

CONCLUSION

Tuberculosis training should be directed toward high-risk areas, including intensive care units, emergency departments, and acute medicine wards. Large-scale training is time-consuming and expensive. Evaluation remains difficult. To facilitate compliance, pretest and posttest results should be provided, linked to Occupational Safety and Health Administration compliance and quality indicators for the hospital.

Acute complications of diabetes mellitus

Blood glucose control is challenged frequently for patients with diabetes mellitus. Illness, stress, and unplanned life events often make glycemic control unstable, which puts the patient at risk for hypoglycemia or hyperglycemia. These acute complications may be mild and managed independently by the patient, or they may be severe, thus threatening life and requiring intensive monitoring. Outcomes are improved with timely recognition of the patient at risk, their symptoms, and appropriate intervention.

Thyroid dosimetry of adult European populations

Radioactive iodine, in the form of iodine-131, behaves similarly to stable iodine in small quantities, thus resulting in a radiation dose to the thyroid. Under the Medical Internal Radiation Dosimetry Committee formulation for radiation dose calculation to an organ, the resulting dose to the thyroid gland is dependent on the organ mass, its isotope uptake and the effective half-life of the element in the gland. Traditionally, values have been used for these parameters which, in some cases, were determined some decades previous. Iodine supply is a primary contributor to correct thyroid function and ultimately these values of mass, uptake and half-life. Recently, new data have become available on iodine kinetics throughout Europe. Here, the influence of the highly variable iodine supply in Europe on projected thyroid doses is determined. Thyroid mass values ranged from 9 g (Sweden) to 28 g (Poland) while uptake measurements were found to range from 18% (Finland) to approximately 60% (Germany and Poland). Resulting dose estimates ranged from 0.5 Gy MBq-1 (Finland) injested to 1.3 Gy MBq-1 (Czechoslovakia) injested. It was also found that among European populations the highest dose burden was to those populations with mild iodine deficiency. The results show that the use of generic metabolic data for the thyroid can lead to a misrepresentation of the absorbed dose to the thyroid. Thus, the data presented provide a better reflection of the actual thyroid dose following ingestion of iodine-131 for European countries.

Regulation of hippocampal theta activity by corticosterone: opposing functions of mineralocorticoid and glucocorticoid receptors

Recently, we reported that intrahippocampal cholinergic blockade increased corticosterone (CORT) and adrenocorticotrophin (ACTH) secretion induced by restraint stress. These data suggested to us that CORT may modify hippocampal cholinergic function as part of the negative-feedback control of hypothalamic-pituitary-adrenal (HPA) axis activity. Hippocampal cholinergic theta is a rhythmic, sinusoidal waveform that occurs in alert, immobile rats presented with threatening stimuli and is reliably expressed in urethanized rats. We reasoned that if hippocampal cholinergic systems regulate HPA axis activity, perhaps CORT acts to modulate theta activity. In the present study we have examined the effects of blocking mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) on theta activity in urethane-anesthetized rats. Adult male, Lister hooded rats (n=15) were anesthetized with urethane, and a theta recording electrode was positioned in the hippocampus adjacent to an infusion cannula. A bipolar stimulating electrode was placed in the dorsomedial posterior hypothalamus (DMPH) to activate theta. Baseline recordings of DMPH-stimulated activity (0.1-0.5 mA) were obtained. Rats were then administered either the MR antagonist spironolactone or the GR antagonist RU 38486 (150 ng), and DMPH-stimulated activities were monitored for 45 min. Changes in theta frequency (Hz) and amplitude (mV; energy at peak theta frequency) were analyzed using analysis of variance (ANOVA) followed by Bonferroni t-tests. Neither drug affected hippocampal theta frequencies elicited by DMPH stimulation. However, GR blockade produced marked increases in theta amplitudes of approximately 100% above predrug levels. Alternatively, MR blockade produced exactly the opposite response, as amplitude values fell to approximately 50% of predrug levels. Hippocampal cholinergic theta activity is modulated by CORT acting through MR and GR, and the rapidity of the response suggests a nongenomic mechanism. These data raise the possibility that hippocampal cholinergic systems, and theta activity, are involved in CORT-mediated negative-feedback control of the HPA axis.

Ontogeny of the vasopressin and oxytocin RNAs in the mouse hypothalamus

The single-copy genes encoding the vasopressin and oxytocin prepropeptides are closely linked in mouse genome, being separated by an intergenic region of only 3 kbp. These genes are expressed in anatomically defined hypothalamic neurons--in the adult rodent, vasopressin is synthesised in the paraventricular nucleus and the supraoptic nucleus, and in the dorsomedial region of the suprachiasmatic nucleus, whilst oxytocin is expressed in the supraoptic nucleus and paraventricular nucleus, but not in the suprachiasmatic nucleus. The molecular mechanisms that mediate the cell-specific and developmental expression patterns of the two transcription units within the vasopressin-oxytocin locus remain to be elucidated. As a first step in this process, we have used in situ hybridisation to study the expression of the RNAs encoded by the linked vasopressin and oxytocin genes during the development of the mouse hypothalamus. We have revealed a hierarchy of gene activation events, with vasopressin first being observed in presumptive supraoptic nucleus at day 13.5, and in the paraventricular at day 14.5. Oxytocin is seen first in the paraventricular at day 15.5; expression in the supraoptic nucleus is clearly seen at day 18.5. As early as day 15.5, the vasopressin and oxytocin RNAs are expressed in different groups of neurons.