Detection of human herpesvirus 8 DNA in Kaposi's sarcoma lesions and peripheral blood of human immunodeficiency virus-positive patients and correlation with serologic measurements

Polymerase chain reaction (PCR) was used to examine human herpesvirus 8 (HHV-8) DNA from Kaposi's sarcoma (KS) lesions, normal skin, and peripheral blood mononuclear cells (PBMC) from human immunodeficiency virus (HIV)-infected patients who did or did not have KS. Of 9 KS biopsies, 8 were positive for five HHV-8 open-reading frames and ranged from 1 viral genome per 2.5-12.7 cells. Two putative replicative gene RNAs were detected by reverse transcription-PCR at low levels in 1 KS lesion. HHV-8 DNA was detected in 4 of 8 PBMC samples from patients with KS and in 2 of 18 PBMC samples from patients without KS. Sera were tested for reactivity with BCBL-1 cells (HHV-8 positive): High immunofluorescence antibody titers against HHV-8 lytic and latent antigens were detected in samples from KS-positive patients, and >20 polypeptides from induced BCBL-1 cells were recognized. Sera from 6 of 18 patients without KS showed low levels of antibodies against HHV-8 lytic and latent antigens.

In situ hybridization: identification of rare mRNAs in human tissues

In situ hybridization is used for detection of RNA expression when conservation of tissue architecture is important. Most in situ hybridization protocols are written for tissues from animals (i.e., rat) which can be harvested and preserved rapidly. In contrast, human tissue is more difficult to obtain, hence in situ hybridization experiments must frequently be performed with less than optimal tissue preservation. This procedure details hybridization of a radiolabeled single-stranded RNA probe (riboprobe) to complementary sequences of cellular RNA in human tissue sections. This method enables detection of rare mRNA species in specific cell types of human tissue, offering distinct advantages over other in situ methods due to increased sensitivity. In particular, we have found that UV cross-linking and ribonuclease treatment protocols need to be altered for human tissues to ensure successful results, making this protocol unique to those previously described. In situ hybridization experiments can be performed using either DNA or RNA probes. RNA probes are advantageous since they form stable hybrids, are single-stranded, have little or no reannealing during hybridization, and can be synthesized to high specific activity. RNA probes can be readily created utilizing SP6, T3, or T7 promoters in both sense and antisense orientations to provide non-specific (control) and specific probes. Disadvantages of RNA riboprobes include a tendency for RNA to stick non-selectively more than DNA, and degradation by RNase (hence strict adherence to RNase-free precautions is mandatory during most of the protocol). The following protocol includes: (1) preparation of human tissues (tissue fixation and sectioning are highlighted as critical for probe penetration, preservation of tissue architecture, retention of tissue RNA, and overall success); (2) generation of radiolabeled riboprobes (total incorporation of radionucleotide is important to increase sensitivity; 35S was chosen as a compromise between excellent sensitivity, cellular resolution, and required exposure times (compared with 32P or 3H); non-isotopic methods have not been tested in a side-by-side comparison with 35S in human tissues by us, but theoretically might offer faster exposure times while maintaining high resolution); (3) hybridization conditions (stringency, temperature, washes, tissue dehydration); and (4) sample visualization (application of photographic emulsion, developing, fixing, staining, and counterstaining of individual slides).

Alpha1-adrenergic receptor blockade blocks LH secretion but not LHRH cFos activation

Long-standing pharmacological evidence supports a role of alpha-noradrenergic receptors in regulating LH release, yet little is known of the action of these receptors on LHRH neurons at the cellular level. We conducted a series of studies aimed at examining the effects of alpha-adrenergic receptor blockade on LH secretion and the cellular activation of LHRH neurons on proestrus. Our initial study used an irreversible alpha-receptor blocker, phenoxybenzamine (alpha1 > alpha2). A group of proestrous rats were treated with phenoxybenzamine at doses of 20 mg/kg, intraperitoneally, or 2, 10 and 20 mg/kg, intravenously, and compared with vehicle injected controls. Phenoxybenzamine administered intraperitoneally did not completely block the LH surge in all animals, whereas all intravenous doses consistently blocked the LH surge. cFos activation of LHRH neurons, on the other hand, was either unaffected or only slightly reduced by phenoxybenzamine treatment intraperitoneally. The effects of intravenous phenoxybenzamine were different, in that at all dose levels phenoxybenzamine completely blocked the LH surge and reduced by approximately half, the cFos activation in LHRH neurons (independent of dose). The effects of intravenous phenoxybenzamine could be mimicked by substitution of prazosin (an alpha1 antagonist, 4 mg/kg), but not idazoxan (an alpha2 antagonist, 1 mg/kg), administered intravenously at 11.00 h and 13.00 h on proestrus. These data provide evidence that noradrenergic systems operating through alpha1-receptors in the neuronal chain leading to the LH surge, while critical for the release of LHRH at the time of an LH surge, are not responsible for the cFos transcriptional changes in LHRH neurons that accompany the natural LH surge.

Psychoactive cannabinoids increase mortality and alter acute phase cytokine responses in mice sublethally infected with Legionella pneumophila

Marijuana contains both psychoactive and nonpsychoactive cannabinoids which have varying effects on the immune response system. Previous studies with delta-9-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, showed that this substance augmented the susceptibility of mice to infection with the opportunistic pathogen Legionella pneumophila. The present study compared the enhancement of Legionella-induced mortality in mice due to two other major of marijuana components, cannabinol and cannabidiol, as well as the synthetic psychoactive cannabinoid CP 55,940. Inbred BALB/c mice, relatively resistant to infection with Legionella, were given the marijuana component 1 day before and 1 day after a sublethal intravenous infection with Legionella. Unlike the effect of THC, an 8 mg/kg dose of either cannabinol or cannabidiol did not affect mortality of the mice sublethally infected with Legionella. Mice given a 16 mg/kg dose of these components of marijuana, however, showed a slight to moderately increased mortality following the sublethal infection with Legionella. In contrast, a dose of 6 mg/kg of the synthetic psychoactive cannabinoid CP 55,940 given 1 day before and 1 day after infection with Legionella resulted in about 50% of the animals dying, the same level of augmentation of lethality induced by THC. Liver, spleen, and lung tissues were removed from the surviving mice 24 hr after the second THC injection and tested for the presence of viable Legionella using a standard CFU assay. The mice injected with THC before and after infection showed significantly higher levels of bacteria in their lung than mice that were not given any cannabinoid but were infected sublethally with the Legionella. Mice injected with the other cannabinoids, including the synthetic cannabinoid, showed a much smaller increase in the number of Legionella in their lung when infected with Legionella and treated with the drug. The number of bacteria recovered from the kidney and liver of the mice regardless of treatment with a cannabinoid, including with THC, did not show significant changes. RNA isolated from the spleen of the THC- and Legionella-treated animals was examined to determine at the molecular level whether acute phase pro-inflammatory cytokines (i.e., IL-1, IL-6 and TNF-alpha) were altered following drug treatment and infection, since previous studies had shown there were increased serum levels of these cytokines in the mice. It was found that the mRNA levels for IL-1 remained generally constant regardless of whether the infected animals were treated with a cannabinoid. However, the mRNA level for IL-6 was markedly increased following treatment of the infected animals with THC, suggesting the possible involvement of this pro-inflammatory cytokine in increased mortality. The mRNA level for TNF-alpha was generally low and not significantly altered in the drug treated animals. Mice given other cannabinoids, including cannabinol and cannabidiol, as well as the synthetic CP 55,940, showed no significant change in the level of mRNA for any of the cytokines tested.

Antibody responses to gut bacteria in ankylosing spondylitis, rheumatoid arthritis, Crohn's disease and ulcerative colitis

Specific immunoreactive anti-Klebsiella antibodies are found in patients with ankylosing spondylitis (AS), a significant proportion of whom have occult inflammatory bowel disease. Molecular mimicry between Klebsiella or other bacterial antigens and HLA-B27 has been suggested in the pathogenesis of AS. The specificity of increased immunoreactivity against Klebsiella remains to be assessed against the abundant anaerobic bacterial flora, present either in healthy controls or in patients with ulcerative colitis (UC) and Crohn's disease (CD). Total immunoglobulin (Ig; IgG, IgA, IgM) immunoreactivity was measured by ELISA against Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli and ten anaerobic isolates of the predominant normal bowel flora in 35 patients with active AS, 60 patients with inflammatory bowel disease (30 CD, 30 UC), 60 patients with active rheumatoid arthritis (RA) and 60 healthy controls. Ig immunoreactivity to K. pneumoniae was significantly elevated in AS (P < 0.001), CD (P < 0.001) and UC (P < 0.001) patients compared with RA patients and healthy controls. Furthermore, Ig immunoreactivity to P. mirabilis was significantly elevated only in RA patients, compared with the other inflammatory groups (P < 0.001) and controls (P < 0.001). There was no significant antibody response against E. coli or the ten obligate anaerobes in any of the test groups. The data suggested an increased immune response to Klebsiella in patients with AS, UC, CD and to Proteus in patients with RA. The specificity of these responses in some patients supported a possible role for enteric Klebsiella in the pathogenesis of AS and Proteus in RA. The role of Klebsiella in inflammatory bowel disease requires further study.

Central hypotensive effects of the alpha2a-adrenergic receptor subtype

alpha2-Adrenergic receptors (alpha2ARs) present in the brainstem decrease blood pressure and are targets for clinically effective antihypertensive drugs. The existence of three alpha2AR subtypes, the lack of subtype-specific ligands, and the cross-reactivity of alpha2AR agonists with imidazoline receptors has precluded an understanding of the role of individual alpha2AR subtypes in the hypotensive response. Gene targeting was used to introduce a point mutation into the alpha2aAR subtype in the mouse genome. The hypotensive response to alpha2AR agonists was lost in the mutant mice, demonstrating that the alpha2aAR subtype plays a principal role in this response.

Morning versus evening dosing of lansoprazole 30 mg daily on twenty-four-hour intragastric acidity in healthy subjects

BACKGROUND

Morning dosing is usually recommended with proton pump inhibitors, but there are few data from 24-h intragastric acidity studies comparing times of dosing.

METHODS

A double-blind, placebo-controlled study was performed on the seventh day of dosing to compare the effects of lansoprazole 30 mg given either in the morning or evening on 24-h intragastric acidity in 32 healthy volunteers.

RESULTS

The median integrated 24-h intragastric acidity on the seventh day of morning dosing with lansoprazole 30 mg was decreased to 36% of the placebo value, compared with 42% for evening dosing. For each daytime meal-related interval, morning dosing was significantly more effective for controlling acidity, but there was no significant difference between the regimens during the night interval (23.00-08.00 h).

CONCLUSIONS

These data favour morning dosing of lansoprazole 30 mg for routine use, but patients with mainly nocturnal symptoms may be best treated by evening dosing.

Production and characterization of fetal sheep pancreatic islet-like cell clusters

Explants of fetal sheep pancreas transplanted into diabetic athymic mice survive for many months but there is only partial differentiation of the endocrine cells. As an alternative form of graft we examined the possibility of creating islet-like cell clusters (ICCs) by collagenase digestion of the fetal sheep pancreas, as has been described for human and porcine fetal pancreas. Such ICCs did form at the rate of 6-23 per 10 mg pancreas; their size varied between 65 and 474 microns (median 232 microns) and their insulin content was 1.6 +/- 0.2 mU per 20 ICCs. Laser scanning confocal analysis showed that 4.6 +/- 0.7% of the cells contained insulin. Insulin was secreted from ICCs maintained in culture at the daily rate of 2.5 mU per 30 ICCs. Arginine but not glucose or theophylline enhanced acute insulin secretion in vitro. Transplantation of up to 1000 ICCs into athymic and acid mice resulted in sparse growth of the epithelial-like cells in the graft and only partial differentiation of the endocrine cells. Hyperglycaemia in diabetic recipients was not normalized. Thus, while functioning ICCs can be created from fetal sheep pancreas, they do not appear to be appropriate for transplantation to reverse diabetes in mice.

Thrombotic vascular risk factors in inflammatory bowel disease

BACKGROUND

Thrombosis may be an important effector mechanism in the pathogenesis of Crohn's disease.

METHODS

This study therefore investigated the prevalence of independent thrombotic risk factors (factor VII coagulant activity, lipoprotein (a), fibrinogen, plasma triglycerides, and smoking) in patients with Crohn's disease, ulcerative colitis, and normal controls.

RESULTS

In Crohn's disease (n = 75), the mean plasma VII:C, lipoprotein (a) and fibrinogen concentrations were significantly greater than in the normal population (n = 85). In ulcerative colitis (n = 35), only the mean factor VII:C concentration was significantly higher than normal. Ninety three per cent of patients with Crohn's disease and 86% of those with ulcerative colitis had at least one risk factor for thrombotic vascular disease, compared with 61% of the normal population (p < 0.001).

CONCLUSIONS

In many young patients with inflammatory bowel disease, plasma concentrations of these prothrombotic factors were in excess of the limits that are regarded as posing an increased risk for the development of occlusive vascular disease.

Disposition and excretion of 6-methoxy-2-naphthylacetic acid, the active metabolite of nabumetone in horses

OBJECTIVE

To examine, in horses, the disposition and excretion of the active metabolite 6-methoxy-2-naphthylacetic acid (6MNA) of the nonsteroidal anti-inflammatory prodrug nabumetone.

DESIGN

Pharmacokinetic analysis of 6MNA after oral administration of nabumetone and IV administration of 6MNA.

PROCEDURE

Using a crossover design, 5 horses were orally administered 3.7 mg of nabumetone/kg of body weight. After a 3-week washout period, 4 horses were administered 2.5 mg of 6MNA/kg, IV.

RESULTS

Absorption of nabumetone from the gastrointestinal tract and its metabolism to 6MNA had a median appearance half-life of 0.88 hour. The elimination half-life was 11 hours. Area under the plasma concentration time curve for 6MNA after oral administration of nabumetone was 120.6 mg/h/L. A dose of 2.5 mg/kg of 6MNA administered IV resulted in plasma concentration nearly equivalent to that induced by the orally administered dose. Disposition of 6MNA was modeled as a one-compartment, first-order elimination. The area under the plasma concentration time curve for IV administration of 6MNA was 117.0 mg/h/L, and the specific volume of distribution was 0.247 L/kg. The distribution half-life and the elimination half-life were 0.56 and 7.90 hours, respectively. Percentage of total dose recovered in urine for the 36-hour collection period after the oral and IV administrations was 7.4 and 5.3%, respectively.

CONCLUSIONS

Metabolism of nabumetone to 6MNA, as reported in other species, also occurs in horses. There were a number of additional metabolites of nabumetone in urine that could not be fully identified and characterized.

Comparison of the polymerase chain reaction and serology for the diagnosis of HTLV-I infection

Human T-lymphotropic virus type I (HTLV-I) is associated with tropical spastic paraparesis (TSP) and adult T-cell leukaemia/ lymphoma (ATL). HTLV-I seroconversion may not take place for many years after infection and some patients develop relatively low concentrations of antibodies that are difficult to detect by means of conventional assays. Some serologic tests also yield high rates of false-positive results. We therefore decided to determine whether the polymerase chain reaction (PCR) might be more sensitive than serology for the diagnosis of HTLV-I infection. Samples of serum and of peripheral blood mononuclear cells were obtained from 50 patients with spastic myelopathy and nine with T-cell neoplasia. The serum samples of serum were tested for the presence of HTLV-I antibodies by means of an enzyme-linked immunosorbent assay (ELISA). Positive results were confirmed by Western blot (WB) assay. DNA was extracted from the peripheral blood mononuclear cells and a PCR performed by use of two primer pairs from the env and pol regions of the proviral genome. Seven of the 50 patients with myelopathy and none of those with T-cell neoplasia had detectable antibodies to HTLV-I and all seven were PCR positive. One patient with an indeterminate WB result and one who was HTLV-I antibody-negative, both with myelopathy, were also PCR-positive. In this study, PCR was found to be more sensitive than serology for the diagnosis of HTLV-I infection. PCR should therefore be considered for selected HTLV-I antibody-negative patients with unexplained spastic myelopathy or T-cell neoplasia.

Locus of control, social support, and adherence to the diabetes regimen

There is a need to better understand how psychosocial factors influence regimen adherence behavior. Therefore, the purpose of this study was to assess the ability of internal diabetes locus of control and social support to predict adherence to a weight-control regimen among persons with non-insulin-dependent diabetes mellitus (NIDDM). A community-based sample of 465 patients with NIDDM was interviewed. Regression analyses revealed that internal locus of control and social support were modest but statistically significant predictors. Correlation analyses showed that internal locus of control was not related to weight control in the high social support group. In the low social support group, a stronger internal locus of control was not associated with weight management. The ways in which internal locus of control and social support work together were not clear. The findings suggest that these two factors are advantageous for promoting regimen adherence.

An introduction to transoesophageal echocardiography: II. Clinical applications

PURPOSE

As progress has been made in the acquisition of cardiac images with transoesophageal echocardiography, the technique has moved from the confines of the cardiology laboratory into the operating room, the intensive care unit, and the emergency department. This has afforded anaesthetists the opportunity to become familiar with, and develop expertise in its practice. The purpose of this article is to present a review of transoesophageal echocardiography with reference to anaesthetic practice.

SOURCE

The principle source of material was a computerized MedlineTM search of the English language literature from 1986 to 1995.

PRINCIPLE FINDINGS

After discussing the technique of probe insertion, and describing some of the standard images, transoesophageal echocardiography's clinical utility is critically assessed. Comparisons with available monitoring techniques are made with reference to ventricular function, valvular heart disease, pericardial, aortic and congenital heart disease, and the management of the multiple traumatized patient. Issues of certification and maintenance of competence are also discussed.

CONCLUSION

Although the benefit of transoesophageal echocardiography is intuitive in many clinical situations, in others, it has not been shown to improve upon presently existing monitoring techniques. The need for adequate training and collaboration with cardiology colleagues is emphasized.

HTLV-I infection in the Free State region of South Africa: a sero-epidemiologic study

Human T-lymphotropic virus type I (HTLV-1) is associated with tropical spastic paraparesis (TSP) and adult T-cell leukemia/lymphoma. HTLV-I infection is endemic in certain parts of the Natal/KwaZulu region of South Africa. No studies on the seroprevalence of HTLV-I infection in the Free State (FS) have been published. This study was designed to determine the prevalence of HTLV-I antibodies among different patient groups in the FS. Sera from 863 patients were analyzed. There were: 178 asymptomatic rural Blacks, 200 asymptomatic urban Blacks, 50 asymptomatic Whites, 60 patients with spastic myelopathy, 70 patients with other neurologic disorders, 12 patients with T-cell haematologic malignancies and 293 human immunodeficiency virus (HIV) seropositive patients. Sera were tested for the presence of HTLV-I/II antibodies using an enzyme linked immunosorbent assay (ELISA). Positive results were confirmed using a modified Western blot assay. None of the asymptomatic Whites were HTLV-I antibody positive (95 pc confidence interval (CI): 0 to 7 pc), while 2 pc (95 CI: 0.5 to 5 pc) of asymptomatic urban Blacks and 1.1 pc (95 pc CI: 0.14 to 4 pc) of asymptomatic rural Blacks had HTLV-I antibodies. Of the group of patients with spastic myelopathy 33.3 pc (95 pc CI: 21.7 to 46.7 pc had HTLV-I antibodies, while none of the patients with T-cell haematologic malignancies (95 pc CI: 0 to 26.5 pc) or other neurologic disorders (95 pc CI: 0 to 5 pc) had HTLV-I antibodies. Of the HIV seropositive patients 6.1 (95 pc CI: 4 to 9.5) were co-infected with HTLV-I. HTLV-I infection is present in the Free State. It is strongly associated with spastic myelopathy in this region. HIV seropositive patients have a high rate of HTLV-I co-infection.

A novel method of preparing PLGA microcapsules utilizing methylethyl ketone

PURPOSE

To substitute dichloromethane with a safer solvent, a solvent extraction process using methylethyl ketone (MEK) was developed to prepare poly(d,l-lactide-co-glycolide) microcapsules.

METHODS

The MEK dispersed phase containing PLGA and progesterone was emulsified in the MEK-saturated aqueous phase (W1) to make a transient oil-in-water (O/W1) emulsion. It was then transferred to a sufficient amount of water (W2) so that MEK residing in polymeric droplets could be extracted effectively into the continuous phase.

RESULTS

This solvent extraction process provided the encapsulation efficiency for progesterone ranging from 77 to 60%. The amount of MEK predissolved in W1, as well as the degree of progesterone payload, influenced the encapsulation efficiency. The leaching profile of MEK analyzed by GC substantiated that, upon dispersion of O/W1, to W2, MEK quickly diffused into the continuous phase. Such a rapid diffusion of MEK from and the ingression of water into polymeric droplets produced hollow microcapsules, as evidenced by their SEM micrographs.

CONCLUSIONS

When solvent extraction/evaporation techniques are employed for preparing PLGA microcapsules, water-immiscibility of a dispersed phase is not an absolute prerequisite to the successful microencapsulation. Adjustment of an initial extraction rate of MEK and formation of a primary transient O/W1 emulsion are found to be very crucial not only for the success of microencapsulation but also for the determination of microcapsule morphology.

Perioperative management of drug therapy, clinical considerations

The objectives for the provision of a safe anaesthetic include rendering the patient analgesic for the procedure (amnesic if appropriate), with control of adverse haemodynamic perturbations, and muscle relaxation to facilitate surgery as necessary. This must be done with an understanding of the patient's pre-existing pathophysiology and drug therapy. This article focuses on the management of medications in the perioperative period from the practitioner's perspective. Areas of drug therapy examined include drugs affecting the cardiovascular, central nervous, haemostatic and endocrine systems. Review of the limited data available suggests that the safest course of action for the preoperative management of the vast majority of drug therapy is to continue such therapy until the time of surgery, particularly agents in which a withdrawal syndrome has been described, e.g. beta-adrenoceptor blocking agents, alpha 2-adrenoceptor agonists. Exceptions to this generalisation might include discontinuing ACE inhibitors prior to surgery as these agents may be associated with adverse haemodynamic changes during surgery. The management of drug therapy for patients receiving monoamine oxidase inhibitors (MAOIs) continues to be challenging due to the potential for drug interactions, e.g. severe hypertension with use of indirect-acting vasopressors and excitatory/depressive reactions with administration of pethidine (meperidine) or dextromethorphan. However, recent clinical experience has demonstrated the relative safety of continuing MAOIs prior to surgery by use of specific 'MAOI safe' anaesthetic techniques and/or substitution of short-acting MAOIs which do not irreversibly inhibit the enzyme. For drugs affecting the coagulation system, such as heparin and warfarin, prudence dictates discontinuing these agents whenever possible prior to surgery where it can be anticipated that haemorrhage will occur, e.g. vascular surgery, or where the consequences of even minor bleeding could be catastrophic, e.g. eye surgery. Controversy exists as to the management of patients receiving prophylactic low dose heparin for deep vein thrombosis prophylaxis or in whom intraoperative or postoperative anticoagulation is planned, e.g. aortic surgery, and in whom a regional anaesthetic technique is planned as part of the anaesthetic management. The data available suggest that, where prophylactic use of heparin is concerned, and provided the administration of the last dose of heparin and the institution of a regional anaesthetic nerve block does not occur at the same time, use of regional anaesthesia is not contraindicated in such circumstances. Where therapeutic anticoagulation is planned as part of the surgical management, there is a very small risk of the development of epidural or spinal haematoma when major central conduction nerve block is employed for anaesthesia, with resultant spinal cord compression and paralysis. These precautions do not apply to patients receiving aspirin or other nonsteroidal anti-inflammatory agents as there is a large clinical and published experience of the safety of regional anaesthesia in this group of patients. Patients treated with fibrinolytic agents are at increased risk for bleeding should surgery be required. For these patients, pre- and intraoperative use of agents with antifibrinolytic activity, e.g. aprotinin, has been demonstrated in case reports to be beneficial. Finally, recommendations for the management of patients who have received or are receiving glucocorticoids are given. Throughout the review, areas of uncertainty where further research is required are identified.

Managing Drought in Australia's Rangelands: Four Weddings and a Funeral

We report some of the findings of a project called 'DroughtPlan', which has involved close collaboration with pastoralists throughout the Australian rangelands. There were three general areas related to property management where producers felt better information and training could help them cope with climatic variability. These were strategic management of long-term stocking levels, tactical management of stock numbers between years, and business management skills. A comprehensive series of representative studies linking herd biology with economic outcomes was undertaken on these topics with pastoralists in different regions of the rangelands. Some of the studies considered most important by pastoralists are reported here. These demonstrate that: (i) a reduction in current stocking levels can often improve cash flow; (ii) small adjustments in livestock selling tactics during drought can have large financial ramifications; (iii) it is financially advantageous to build stock numbers up quickly after a drought, even though this may conflict with longer-term environmental values; (iv) while diversification can provide financial rewards, these could be matched by small improvements in the biological rates of the livestock; and, (v) fine-tuning of the existing pastoral enterprise can provide a less risky means of increasing cash flow and reducing its variability than does diversification. Four of the examples indicate that better use of information can help both profitability and sustainability; the fifth suggests that the interests of short-term profitability are in conflict with long-term land conservation goals, as assessed by many pastoralists. These studies highlight the value of linking producer knowledge with a systematic analysis framework, as well as the vital importance of incorporating the effects of climatic variability, when assessing the value of different management options.

The specific contribution of the novel alpha-1D adrenoceptor to the contraction of vascular smooth muscle

With a selective antagonist, the specific contribution of the alpha-1D adrenoceptor (AR) to vascular smooth muscle contraction has been assessed. BMY 7378 bound to membranes expressing the cloned rat alpha-1D AR with a > 100-fold higher affinity (K1 = 2 nM) than binding to either the cloned rat alpha-1A AR (Ki = 800 nM) or the hamster alpha-1B AR (Ki = 600 nM). BMY 7378 exhibited differential potency in inhibiting vascular smooth muscle contraction. In the rat aorta and iliac artery, BMY 7378 was a high-affinity antagonist, producing parallel shifts in the phenylephrine concentration-response curve. The dissociation constants for this compound by Schild analysis were 0.95 and 4 nM for the aorta and iliac artery, respectively. The slopes of these Schild plots were not significantly different from unity. BMY 7378 was a weak antagonist in the rat caudal, mesenteric resistance and renal arteries, with Schild slopes significantly < 1. With ribonuclease protection assays, alpha-1D mRNA was found in all blood vessels examined. These data suggest that (1) BMY 7378 is a selective alpha-1D AR antagonist that can be used in functional systems to assess the contribution of this receptor in vascular smooth muscle contraction; (2) the alpha-1D AR appears to play a major role in the contraction of the aorta and iliac artery; (3) despite the fact that the mRNA for the alpha-1D AR can be detected in the caudal, mesenteric resistance (4) and renal arteries, it does not appear to play a role in mediating contraction of these blood vessels; and (4) expression of alpha-1D mRNA in a particular artery does not ensure that this receptor is involved in regulating the contraction of that artery.

alpha 2-Adrenergic receptors in human spinal cord: specific localized expression of mRNA encoding alpha 2-adrenergic receptor subtypes at four distinct levels

alpha 2-Adrenergic receptor (AR) subtype mRNA (alpha 2a, alpha 2b, alpha 2c) neuronal localization in human spinal cord has not been described. We therefore performed in situ hybridization to identify cell bodies at four levels of human spinal cord (cervical, thoracic, lumbar, sacral) containing alpha 2AR subtype specific mRNA. alpha 2AR mRNA is present in gray matter only (ventral > dorsal; sacral > cervical > thoracic = lumbar). In addition to alpha 2AR mRNA in cell bodies in thoracic and lumbar intermediolateral (sympathetic) and sacral intermediate (parasympathetic) cell columns (lamina VII), all levels in dorsal horn laminae I, II, V, and ventral horn lamina IX, we demonstrate alpha 2AR mRNA in dorsal horn laminae III and IV, and dorsal nucleus of Clarke, where alpha 2ARs have not been described. Previously unreported heterogeneity in alpha 2AR subtype distribution (alpha 2a and alpha 2bAR mRNA present, alpha 2cAR mRNA virtually absent) is found at all sites of alpha 2AR mRNA expression in human spinal cord, including locations known to mediate effects of alpha 2AR agonist drugs on nociception, autonomic function and motor tone. Cervical spinal cord demonstrates a predominance of alpha 2a mRNA signal, while thoracic, lumbar, and sacral spinal cord demonstrate an increasing predominance of alpha 2bAR mRNA. If confirmed at a protein level, these findings have profound implications for therapeutic strategies in managing human pain.

Comprehensive evaluation and treatment of recurrent pediatric headache

Continuity of care with a clinician who has established a therapeutic alliance is the most important aspect of recurrent pediatric headache management. The provider should assume a concerned and supportive manner that promotes self-esteem and self-mastery and control. Patient and family efforts to reduce functional disability and return to normal activities should be strongly reinforced. Treatment regimens should be reviewed for side effects, compliance, and perceived efficacy. Behavioral techniques should be reviewed in detail with opportunities for the clinician to "trouble shoot" any difficulties encountered by the patient. Periods of potentially increased stress (eg, transitions or loss) should be anticipated and managed prospectively. The clinician should periodically reassess possible psychosocial issues and make appropriate mental health referrals. In the long run, regular follow-up by the primary care clinician remains the most important factor in the successful management of recurrent pediatric headache.

Do GnRH neurons express the gene for the NMDA receptor?

Previous studies have revealed that in several animal models, N-methyl-D,L-Aspartate (NMA) stimulates LH secretion by acting at a suprapituitary site. In addition, NMDA receptor antagonists appear to block GnRH neuronal activation on the afternoon of proestrous as evidenced by the lack of c-Fos expression in the neurons and by the absence of an ovulatory LH surge. However, administration of NMA does not induce c-Fos or c-Jun expression in GnRH neurons. To better understand the effects of NMDA receptor activation on GnRH neuronal function, we examined whether GnRH neurons express the NMDA receptor in male rats, and in female rats during diestrus and proestrus, by performing double label in situ hybridization. An 35S-labeled cRNA probe for the NMDA receptor subunit (NMDAR1) was used to quantify NMDAR1 mRNA and a digoxigenin-labeled cRNA probe for GnRH was used to identify GnRH neurons. The data were quantified and expressed as grains/average cell area. In male and female rats, less than 5% of GnRH neurons expressed grain levels twice the minimum detectable level and were considered double-labeled. However, many non-GnRH neurons in the same areas as GnRH neurons expressed high levels of NMDAR1 mRNA. These results suggest that the effects of NMA on GnRH secretion are unlikely to be mediated solely by the activation of NMDA receptors on GnRH neurons. Given the widespread expression of NMDAR1 mRNA in the hypothalamus, it is possible that the stimulatory effects of NMA on GnRH neurons are indirect through activation of other neurons.

Increased GnRH mRNA in the GnRH neurons expressing cFos during the proestrous LH surge

GnRH neuronal activity is increased during the proestrous LH surge as assessed by the expression of cFos. Whether there is an increase in GnRH mRNA concomitant with GnRH neuronal activation is still controversial. In the present study we have compared GnRH mRNA levels in GnRH neurons expressing cFos (activated) with those not expressing cFos during the proestrous LH surge. Brain tissue was obtained from adult female rats perfused on proestrus before (1100-1300 hr) or during (1500-1900 hr) the LH surge. Twenty-five microns free-floating brain sections were subjected to double labeling of cFos by immunocytochemistry and of GnRH mRNA by in situ hybridization using an 35S-labeled cRNA probe. Another series of sections were stained by double-label immunocytochemistry for cFos and GnRH. Serum LH concentrations and cFos expression in GnRH neurons indicated that rats sacrificed at or before 1300 hr had basal levels of LH secretion, and no cFos activity was detected in GnRH neurons. In animals sacrificed between 1500 and 1900 hr, LH concentrations were at levels indicative of the ascending phase of the LH surge. A significant positive correlation between plasma LH values and the proportion of GnRH mRNA-containing neurons expressing cFos was observed. The average cellular GnRH mRNA content (silver grain numbers per cell) during the LH surge was not different from that before the surge. However, if GnRH neurons during the surge were further divided into cFos-positive and cFos-negative neurons, GnRH mRNA levels in the cFos-positive GnRH neurons were significantly increased by 28% when compared with GnRH neurons without cFos expression. These data suggest that cFos expression in GnRH neurons during the proestrous LH surge identifies transcriptionally more active GnRH neurons.

Detection of herpesvirus DNA in cottontop tamarins: no association with colitis

Colitis occurs spontaneously in the cottontop tamarin; it shares similar clinical, endoscopic and histological features with, and has a similar response to treatment as, human ulcerative colitis. An association between human ulcerative colitis and the presence of DNA from multiple herpesviruses (human herpesvirus 6 (HHV-6), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in the colon has been described. Intestinal herpesvirus infection may be involved in the pathogenesis of this condition. In a pilot study, coded full thickness colonic specimens from 27 cottontop tamarins were examined for the presence of HHV-6, CMV and EBV DNA using the nested polymerase chain reaction. The sections represented a spectrum of disease activity ranging from histologically normal bowel to severe colitis. A low prevalence of DNA from these viruses was found, which bore no relation to the presence of inflammation. Although these herpesviruses may have a pathogenetic role in human ulcerative colitis, they are not associated with colitis in this animal model.

Serum concentrations of von Willebrand factor and soluble thrombomodulin indicate alteration of endothelial function in inflammatory bowel diseases

Serum concentrations of immunoreactive von Willebrand factor (vWF) and soluble thrombomodulin (TM), and vWF multimer patterns were measured to assess endothelial function in patients with inflammatory intestinal diseases. In Crohn's disease and acute infective diarrhea, vWF concentrations were significantly higher than in normal controls. In all patient groups, multimeric analysis of vWF and the concentration of serum TM were not different from normal controls. The results indicate alteration of endothelial function in inflammatory intestinal disorders. They may be compatible with the presence of localized vasculitis, but indicate that systemic endothelial destruction does not occur in inflammatory bowel disease.

The development and validation of the Perceived Health Competence Scale

A sense of competence or self-efficacy is associated with many positive outcomes, particularly in the area of health behavior. A measure of a sense of competence in the domain of health behavior has not been developed. Most measures are either general measures of a general sense of self-efficacy or are very specific to a particular health behavior. The Perceived Health Competence Scale (PHCS), a domain-specific measure of the degree to which an individual feels capable of effectively managing his or her health outcomes, was developed to provide a measure of perceived competence at an intermediate level of specificity. Five studies using three different types of samples (students, adults and persons with a chronic illness) provide evidence for the reliability and validity of the PHCS. The eight items of the PHCS combine both outcome and behavioral expectancies. Results from the five studies indicate that the scale has good internal consistency and test-retest reliability. The construct validity of the scale is demonstrated through the support obtained for substantive hypotheses regarding the correlates of perceived health competence, such as health behavior intentions, general sense of competence and health locus of control.

Orthotopic liver transplantation for chronic hepatitis in two patients with common variable immunodeficiency

Two patients with common variable immunodeficiency underwent orthotopic liver transplantation for chronic hepatitis, unequivocally caused by hepatitis C virus in one case. Although one patient had pneumonia 8 days after surgery and the other developed hepatic venular stenosis in the transplanted liver, both had a reasonably good quality of life for at least 15 months. However, both subsequently died of recurrent hepatitis C virus hepatitis or hemorrhage after splenectomy for hypersplenism. This shows that severe infection is not a major problem in patients with common variable immunodeficiency after liver transplantation provided they undergo prophylactic antimicrobial and immunoglobulin therapy. The longer term prognosis must be regarded as poor until more data are available following transplantation in similar patients.

Sickness absence in male Royal Naval medical and dental branch ratings: 1981-1989

Sickness episodes for the male members of the medical and dental branch of the Royal Navy were compared with those for a control group consisting of other male naval ratings over the period 1981-1989. Age-corrected statistical analysis showed the study group to have had a significantly higher (P < 0.001) number of sickness episodes. An estimate of under-reporting was carried out by taking a sample of weekly sick lists and establishing which cases should have been reported and which actually had been reported. In the sample from a naval hospital, 67.8% (120/177) of cases that should have been reported were actually reported. This figure dropped to 46.8% (171/365) for a naval shore establishment. From this information, correction factors were derived and applied to the sickness episode data. The resulting difference in episodes was not statistically significant between groups. When the study group was compared with male NHS workers, both the observed rates and the estimated rates for the study group were much lower than those for the NHS groups. Bias due to under-reporting was probably a major factor in the overall difference originally observed.

Perceived anxiety of pediatric patients to magnetic resonance

Magnetic resonance imaging (MRI), a nonionizing radiologic technique without known adverse physical effects, is utilized frequently in children and adolescents. The MRI technique requires prolonged immobility in a narrow, confined space, and concern has been raised regarding possible patient anxiety and noncompliance. Several reports suggest that up to 10% of adults undergoing MRI may experience anxiety and/or claustrophobia. 1 However, to our knowledge, no studies of the subjective MRI experiences of children and adolescents have been published. We report here the general characteristics of 491 consecutive Pediatric patients who were evaluated with MRI at our institution, including the experience of anxiety in 85 older children and adolescents.

"I have a future" comprehensive adolescent health promotion: cultural considerations in program implementation and design

"I Have a Future" Adolescent Health Promotion Program is a life options program. The program uses the Nguzo Saba (seven principles) and African philosophy to systematically address violence and attitudes reinforcing the use of violence. The Nguzo Saba promotes self-respect, and commitment to and support for developing a positive community. Data was collected from four public housing developments--two served as match control sites. Adolescents residing in neighborhoods in which the program operated had greater acceptance of the Nguzo Saba than those in matched communities. Those who perceived themselves as having life options engaged in fewer delinquent/violent acts. There was a strong negative correlation between the acceptance of the Nguzo Saba and the number of reported delinquent/violent behaviors. There was a positive relationship between the acceptance of the Nguzo Saba and positive self-concept, psychosocial maturity, and clarity of goals.

Lactation-induced deficits in NMDA receptor-mediated cortical and hippocampal activation: changes in NMDA receptor gene expression and brainstem activation

During lactation, there is an inhibition of cortical and hippocampal activation in response to N-methyl-D,L-aspartate (NMA), but not kainate, as assessed by induction of c-Fos expression. To study whether changes in NMDA receptor function may account for this inhibition, NMDA receptor subunit (NMDAR1) mRNA levels were measured by both Northern analysis and in situ hybridization. Analysis of NMDAR1 gene expression by Northern blot analysis did not reveal significant differences between cycling and lactating rats. Using in situ hybridization, NMDAR1 mRNA levels in several cortical and hippocampal areas appeared to be smaller in lactating rats, compared to cycling rats, although these differences reached significance only in the fronto-parietal cortex and piriform cortex. These subtle changes in NMDAR1 receptor subunit gene expression during lactation are not likely to account for the global lack of neuronal activation in response to NMA. However, it is possible that there may be changes in other NMDA receptor subunits that could account for the deficits in NMDA receptor activation. We also examined the activation state of afferent pathways in the brainstem that provide excitatory input to the cortex and hippocampus. During lactation, NMA induced c-Fos expression in similar areas of the brainstem as during the cycle, except in the locus coeruleus and dorsal raphe, where c-Fos expression was significantly less than that observed during the cycle. In contrast, no differences in the pattern of c-Fos expression in the brainstem in response to kainate were observed between cycling and lactating rats. The lack of NMA-induced activation of the locus coeruleus and dorsal raphe may contribute to the lack of cortical activation during lactation.

Antibiotic prophylaxis for urodynamic testing in patients with spinal cord injury: a preliminary study

This study was performed in order to: (i) determine the incidence of symptomatic urinary tract infection (UTI) in patients with spinal cord injury after urodynamic testing; (ii) evaluate the role of antibiotic prophylaxis for such a procedure; and (iii) investigate whether pre-existing bacteriuria predisposes to the development of symptomatic UTI after urodynamic testing. Forty patients were prospectively randomized in a double-blind fashion to receive a 3-day oral course of either ciprofloxacin (18 patients) or placebo (22 patients), beginning 2 days prior to the urodynamic procedure. None of 18 (0%) patients who received ciprofloxacin developed symptomatic UTI within 5 days after the procedure compared with three of 22 (14%) subjects randomized to the placebo group; the protective efficacy of antibiotic prophylaxis, however, did not attain statistical significance (P = 0.24). None of the three bacterial isolates that were responsible for symptomatic infection were grown in corresponding urine cultures prior to the procedure. These findings may serve as a pilot for a larger study.

Use of Fos-related antigens (FRAs) as markers of neuronal activity: FRA changes in dopamine neurons during proestrus, pregnancy and lactation

This manuscript describes the use of staining of Fos-related antigens (FRAs) as markers for changes in neuronal activity. The model system consisted of the tuberoinfundibular dopamine (TIDA) neurons located in the arcuate nucleus of the hypothalamus. Under normal conditions, these neurons are devoid of c-Fos staining even though the neurons are tonically active and can express FRAs. During specific neuroendocrine states the neurons undergo changes in activity, as described by other studies. At times when the activity is relatively high as in pregnancy and during proestrus, approximately 50%-60% of the TIDA neurons expressed FRA immunoreactivity. Moreover changes over the course of proestrus paralleled known shifts in TIDA activity (declining as the day progressed). At times when TIDA activity is suppressed, such as during lactation, FRA staining in TIDA neurons was markedly reduced or absent. Upon removal of the suckling stimulus, FRA staining rose to reach peak expression 12-24 h after pup removal (without coordinate induction of c-Fos). These data suggest that FRA staining can serve as a useful marker of activity in the TIDA neurons which permits not only assessment of stimulated activity but also suppressed function in the neurons. A cautionary note in using this approach along with acquisition of serial blood samples for hormone measurement is that surgical procedures for monitoring plasma hormone levels are associated with strong long-lived induction of FRAs (and c-Fos) in many neurons (including the TIDA neurons) that can confound interpretation of FRA staining.

Identification of the mRNA for the novel alpha 1D-adrenoceptor and two other alpha 1-adrenoceptors in vascular smooth muscle

In situ hybridization histochemistry, radioligand binding, and in vitro contractile studies were used to characterize the vascular distribution of the recently discovered alpha 1D-adrenoceptor. In situ hybridization with an antisense probe localized the mRNA for the alpha 1D-adrenoceptor to the medial layer of the rat aorta renal and mesenteric resistance arteries. If the tissues were first treated with RNase or a sense probe was used, no specific hybridization signal was detected. The extent to which this receptor was expressed as protein was assessed with radioligand binding studies. A series of ligands used to characterize alpha 1-adrenoceptors interacted with two sites labeled by [3H]prazosin in homogenates from the aorta and mesenteric vascular bed. The high affinity site had the characteristics of an alpha 1A-adrenoceptor. However, the low affinity site had ligand binding characteristics distinct from those of the alpha 1D-adrenoceptor or any other known alpha 1-adrenoceptor subtype. mRNA for the alpha 1B- and alpha 1C-adrenoceptors was also detected in the aorta, renal arteries, and mesenteric resistance arteries. Chloroethylclonidine (CEC) (1 and 10 microM) had differential effects on phenylephrine-induced contractions of vascular smooth muscle. CEC completely inhibited the response in the aorta and caused a partial inhibition in the mesenteric resistance artery. The same concentrations of CEC had little effect on phenylephrine responses in the renal artery. The data suggest the following. 1) mRNA for the novel alpha 1D-adrenoceptor is localized in vascular smooth muscle. 2) Definitive identification of expression of this receptor was not possible; this may be related to coexpression of other subtypes of alpha 1-adrenoceptors. 3) mRNA for the alpha 1C-adrenoceptor was detected in rat peripheral vasculature. 4) The alpha 1A-adrenoceptor is also localized in the vasculature. 5) Three and possibly four alpha 1-adrenoceptors participate in vascular smooth muscle regulation.

The use of human lung slices in toxicology

1. Successful use of agar-filled precision-cut rat lung slices in dynamic organ culture prompted the use of this technology with human lung. 2. The larger tissue mass of a human lung required that the trachea be cannulated with a balloon catheter and subsequently inflated with 4 liters of warm agar/medium mixture and then cooled before being precision-cut into 500 microns thick slices. 3. To characterize the human lung slices, viability and the effects of acrolein and nitrofurantoin were assessed over a period of 24 h using protein synthesis and nonprotein sulfhydryl content. 4. Control human lung slices synthesized protein at a linear rate and maintained a stable nonprotein sulfhydryl content for 24 h. 5. Slices incubated with acrolein exhibited no significant decrease in protein synthesis or nonprotein sulfhydryl levels until 24 h. 6. Incubation with nitrofurantoin exhibited a definite time- and dose-dependent inhibition of protein synthesis, and depletion of the cellular thiol pool. 7. These results indicate that this human lung tissue slice system may be used as an in vitro model to identify and screen pneumotoxicants.