A cluster-randomized trial of client and provider directed financial interventions to align incentives with appropriate case management in private medicine retailers: results of the TESTsmART Trial in Lagos, Nigeria

Malaria remains a major health priority in Nigeria. Among children with fever who seek care, less than a quarter gets tested for malaria, leading to inappropriate use of the recommended treatment for malaria; Artemether Combination Therapies (ACT). Here we test an innovative strategy to target ACT subsidies to clients seeking care in Nigeria's private retail health sector who have a confirmed malaria diagnosis. We supported point-of-care malaria testing (mRDTs) in 48 Private Medicine Retailers (PMRs) in the city of Lagos, Nigeria and randomized them to two study arms; a control arm offering subsidized mRDT testing for USD $0.66, and an intervention arm where, in addition to access to subsidized testing as in the control arm, clients who received a positive mRDT at the PMR were eligible for a free (fully subsidized) first-line ACT and PMRs received USD $0.2 for every mRDT performed. Our primary outcome was the proportion of ACTs dispensed to individuals with a positive diagnostic test. Secondary outcomes included proportion of clients who were tested at the PMR and adherence to diagnostic test results. Overall, 23% of clients chose to test at the PMR. Test results seemed to inform treatment decisions and resulted in enhanced targeting of ACTs to confirmed malaria cases with only 26% of test-negative clients purchasing an ACT compared to 58% of untested clients. However, the intervention did not offer further improvements, compared to the control arm, in testing rates or dispensing of ACTs to test-positive clients. We found that ACT subsidies were not passed on to clients testing positive in the intervention arm. We conclude that RDTs could reduce ACT overconsumption in Nigeria's private retail health sector, but PMR-oriented incentive structures are difficult to implement and may need to be complemented with interventions targeting clients of PMRs to increase test uptake and adherence. Clinical Trials Registration Number: NCT04428307.

A cluster-randomized trial of client and provider-directed financial interventions to align incentives with appropriate case management in retail medicine outlets: results of the TESTsmART Trial in western Kenya

ACTs are responsible for a substantial proportion of the global reduction in malaria mortality over the last ten years. These reductions would not have been possible without publicly-funded subsidies making these drugs accessible and affordable in the private sector. However, inexpensive ACTs available in retail outlets have contributed substantially to their overconsumption. We test an innovative, scalable, and sustainable strategy to target ACT subsidies to clients with a confirmatory diagnosis. We supported point-of-care malaria testing (mRDTs) in 39 retail medicine outlets in western Kenya and randomized them to three study arms; control arm offering subsidized RDT testing for 0.4USD, client-directed intervention where all clients who received a positive RDT at the outlet were eligible for a free (fully subsidized) first-line ACT, and a combined client and provider directed intervention where clients with a positive RDT were eligible for free ACT and outlets received 0.1USD for every RDT performed. Our primary outcome was the proportion of ACT dispensed to individuals with a positive diagnostic test. Secondary outcomes included proportion of clients tested at the outlet and adherence to diagnostic test results. 43% of clients chose to test at the outlet. Test results informed treatment decisions and resulted in targeting of ACTs to confirmed malaria cases - 25.3% of test-negative clients purchased an ACT compared to 75% of untested clients. Client-directed and client+provider-directed interventions did not offer further improvements, compared to the control arm, in testing rates (RD=0.09, 95%CI:-0.08,0.26) or dispensing of ACTs to test-positive clients (RD=0.01,95% CI: -0.14, 0.16). Clients were often unaware of the price they paid for the ACT leading to uncertainty in whether the ACT subsidy was passed on to the client. We conclude that mRDTs could reduce ACT overconsumption in the private retail sector, but incentive structures are difficult to scale and their value to private providers is uncertain.

Feasibility study to assess canagliflozin distribution and sodium-glucose co-transporter 2 occupancy using [18 F]Canagliflozin in patients with type 2 diabetes

Sodium-glucose co-transporter 2 (SGLT2) inhibitors, including canagliflozin, reduce the risk of cardiovascular and kidney outcomes in patients with and without type 2 diabetes, albeit with a large inter-individual variation. The underlying mechanisms for this variation in response might be attributed to differences in SGLT2 occupancy, resulting from individual variation in plasma and tissue drug exposure and receptor availability. We performed a feasibility study for the use of [¹⁸ F]Canagliflozin positron emission tomography (PET) imaging to determine the association between clinical canagliflozin doses and SGLT2 occupancy in patients with type 2 diabetes. We obtained two 90-min dynamic PET scans with diagnostic intravenous [¹⁸ F]Canagliflozin administration and a full kinetic analysis in seven patients with type 2 diabetes. Patients received 50, 100 or 300mg oral canagliflozin (n=2:4:1) 2.5 hours before the second scan. Canagliflozin pharmacokinetics and urinary glucose excretion were measured. The apparent SGLT2 occupancy was derived from the difference between the apparent volume of distribution of [¹⁸ F]Canagliflozin in the baseline and post-drug PET scans. Individual canagliflozin area under the curve from oral dosing until 24-hours (AUC_P0-24h ) varied largely (range 1715-25747 μg/L*h, mean 10580 μg/L*h) and increased dose dependently with mean values of 4543, 6525 and 20012 μg/L*h for 50, 100 and 300mg respectively (P=0.046). SGLT2 occupancy ranged between 65 and 87%, but did not correlate with canagliflozin dose, plasma exposure or urinary glucose excretion. We report the feasibility of [¹⁸ F]Canagliflozin PET imaging to determine canagliflozin kidney disposition and SGLT2 occupancy. This suggests the potential of [¹⁸ F]Canagliflozin as a tool to visualize and quantify clinically SGLT2 tissue binding.

Studying Telmisartan Plasma Exposure, Kidney Distribution, Receptor Occupancy, and Response in Patients With Type 2 Diabetes Using [11 C]Telmisartan

The angiotensin receptor blocker telmisartan slows progression of kidney disease in patients with type 2 diabetes (T2D), yet many patients remain at high risk for progressive kidney function loss. The underlying mechanisms for this response variation might be attributed to differences in angiotensin-1 receptor occupancy (RO), resulting from individual variation in plasma drug exposure, tissue drug exposure, and receptor availability. Therefore, we first assessed the relationship between plasma telmisartan exposure and urinary-albumin-to-creatinine-ratio (UACR) in 10 patients with T2D and albuminuria (mean age 66 years, median UACR 297 mg/g) after 4 weeks treatment with 80 mg telmisartan once daily. Increasing telmisartan exposure associated with a larger reduction in UACR (Pearson correlation coefficient (PCC) = -0.64, P = 0.046, median change UACR: -40.1%, 95% confidence interval (CI): -22.9 to -77.4%, mean telmisartan area under the curve (AUC) = 2927.1 ng·hour/mL, 95% CI: 723.0 to 6501.6 ng·hour/mL). Subsequently, we assessed the relation among plasma telmisartan exposure, kidney distribution, and angiotensin-1 RO in five patients with T2D (mean age 60 years, median UACR 72 mg/g) in a separate positron emission tomography imaging study with [¹¹ C]Telmisartan. Individual plasma telmisartan exposure correlated with telmisartan distribution to the kidneys (PCC = 0.976, P = 0.024). A meaningful RO could be calculated in three patients receiving 120 mg oral telmisartan, and although high exposure seems related to higher RO, with AUC_0-last of 31, 840, and 274 ng·hour/mL and corresponding RO values 5.5%, 44%, and 59%, this was not significant (P = 0.64). Together these results indicate, for the first time, a relationship among interindividual differences in plasma exposure, kidney tissue distribution, RO, and ultimately UACR response after telmisartan administration.

Three-year outcome after transanal versus laparoscopic total mesorectal excision in locally advanced rectal cancer: a multicenter comparative analysis

Background

For patients with mid and distal rectal cancer, robust evidence on long-term outcome and causal treatment effects of transanal total mesorectal excision (TaTME) is lacking. This multicentre retrospective cohort study aimed to assess whether TaTME reduces locoregional recurrence rate compared to laparoscopic total mesorectal excision (LapTME).

Methods

Consecutive patients with rectal cancer within 12 cm from the anal verge and clinical stage II-III were selected from three institutional databases. Outcome after TaTME (Nov 2011 - Feb 2018) was compared to a historical cohort of patients treated with LapTME (Jan 2000 - Feb 2018) using the inverse probability of treatment weights method. The primary endpoint was three-year locoregional recurrence.

Results

A total of 710 patients were analysed, 344 in the TaTME group and 366 in the LapTME group. At 3 years, cumulative locoregional recurrence rates were 3.6% (95% CI, 1.1–6.1) in the TaTME group and 9.6% (95% CI, 6.5–12.7) in the LapTME group (HR = 0.4; 95% CI, 0.23–0.69; p = 0.001). Three-year cumulative disease-free survival rates were 74.3% (95% CI, 68.8–79.8) and 68.6% (95% CI, 63.7–73.5) (HR = 0.82; 95% CI, 0.65–1.02; p = 0.078) and three-year overall survival 87.2% (95% CI, 82.7–91.7) and 82.2% (95% CI, 78.0–86.2) (HR = 0.74; 95% CI, 0.53–1.03; p = 0.077), respectively. In patients who underwent sphincter preservation procedures, TaTME was associated with a significantly better disease-free survival (HR = 0.78; 95% CI, 0.62–0.98; p = 0.033).

Conclusions

These findings suggest that TaTME may improve locoregional recurrence and disease-free survival rates among patients with mid and distal locally advanced rectal cancer.

Relation of Plasma Coagulation Factor VII and Fibrinogen to Carotid Artery Intima-Media Thickness

Plasma clotting factor VII and plasma fibrinogen have been claimed as independent risk factors for occlusive cardiovascular disease. The aim of this study was to investigate whether these coagulation parameters affect early atherosclerosis, additional to their possible effect on arterial thrombosis.

We used high-resolution quantitative ultrasonography to measure carotid intima-media thickness in 121 healthy volunteers, aged 18 to 56 years. It has previously been demonstrated that an increased artery wall thickness is seen in advanced atherosclerosis. To validate our methodology for relatively young individuals, we assessed the association of intima-media thickness with the risk-factor status of our subjects, by including classical cardiovascular risk factors, e. g. age, sex, serum cholesterol, smoking habits and blood pressure. Thereafter, we studied the effect of factor VII and fibrinogen plasma levels on carotid intimamedia thickness, as well as that of polymorphisms of the factor VII and fibrinogen genes.

All classical risk factors except smoking and family history were associated with intima-media thickness. When adjusted for by multivariate linear regression analysis, age, blood pressure and cholesterol appeared to be independent determinants of intima-media thickness. Factor VII and fibrinogen levels showed no association in multivariate analysis with intima-media thickness. We conclude that artery wall thickness measurement by ultrasound is a useful tool to investigate the role of clotting factors in early atherosclerosis. Factor VII and fibrinogen levels in young and middle-aged volunteers have no association with early artherosclerotic vessel wall changes.

Validation of the Actical and Actiheart monitor in ambulatory children with spina bifida

BACKGROUND

Ambulatory children with Spina Bifida (SB) often show a decline in physical activity leading to deconditioning and functional decline. Therefore, assessment and promotion of physical activity is important. Because energy expenditure during activities is higher in these children, the use of existing pediatric equations to predict physical activity energy expenditure (PAEE) may not be valid.

AIMS

(1) To evaluate criterion validity of existing predictions converting accelerocounts into PAEE in ambulatory children with SB and (2) to establish new disease-specific equations for PAEE.

METHODS

Simultaneous measurements using the Actical, the Actiheart, and indirect calorimetry took place to determine PAEE in 26 ambulatory children with SB.

DATA ANALYSIS

Paired T-tests, Intra-class correlations limits of agreement (LoA), and explained variance (R(2)) were used to analyze validity of the prediction equations using true PAEE as criterion. New equations were derived using regression techniques.

RESULTS

While T-tests showed no significant differences for some models, the predictions developed in healthy children showed moderate ICC's and large LoA with true PAEE. The best regression models to predict PAEE were: PAEE=174.049+3.861 × HRAR - 60.285 × ambulatory status (R(2) =0.720) and PAEE=220.484+0.67 × Actical counts - 60.717 × ambulatory status (R(2) =0.681).

CONCLUSIONS

Existing equations to predict PAEE are not valid for use in children with SB for the individual evaluation of PAEE. The best regression model was based on HRAR in combination with ambulatory status, followed by a new model for the Actical monitor. A benefit of HRAR is that it does not require the use of expensive accelerometry equipment. Further cross-validation of these models is still needed.

The effect on toxicology, biochemistry and immunology investigations by the use of targeted post-mortem computed tomography angiography

It is recognised in autopsy practice that investigations such as toxicology can be affected by post-mortem change. Post-mortem computed tomography angiography (PMCT-A) involves the injection of contrast agents. This could cause dilution of a biological fluid sample or cause the circulation of blood after death by mechanical pumping, and thus has the potential to affect laboratory investigations. We undertook a small sample study to consider whether targeted PMCT-A had any significant effect on subsequent samples taken for biochemical, toxicological or immunological investigations. Although the results of our study do illustrate differences between the pre and post PMCT-A results, these differences are considered not to be of diagnostic significance and not due to the direct effect of targeted PMCT-A.

Microspheres with ultrahigh holmium content for radioablation of malignancies

PURPOSE

The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an intravascularly placed catheter.

METHODS

Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized using light and scanning electron microscopy, coulter counter, titrimetry, infrared and Raman spectroscopy, differential scanning calorimetry, X-ray powder diffraction, magnetic resonance imaging (MRI), and X-ray computed tomography (CT).

RESULTS

Microspheres, thus prepared displayed a smooth surface. The holmium content of the HoAcAc microspheres (44% (w/w)) was higher than the holmium content of the starting material, HoAcAc crystals (33% (w/w)). This was attributed to the loss of acetylacetonate from the HoAcAc complex, during rearrangement of acetylacetonate around the holmium ion. The increase of the holmium content allows for the detection of (sub)microgram amounts of microspheres using MRI and CT.

CONCLUSIONS

HoAcAc microspheres with an ultra-high holmium content were prepared. These microspheres are suitable for radioablation of tumors by intratumoral injections or treatment of liver tumors through transcatheter administration.

Analysis of thyrotropin-releasing hormone-signaling components in pituitary adenomas of patients with acromegaly

In many acromegalic patients the paradoxical release of GH in response to TRH has been well documented, but the mechanisms underlying this phenomenon are not understood. It has been suggested that aberrant GH secretion may result from TRH endogenously synthesized by the adenoma. In 32 adenomas from acromegalic patients, TRH-like immunoreactivity (TRH-LI) was measured using 2 well characterized antisera. TRH-LI was not detectable in 10 samples, and in 19 samples, TRH-LI was measured only by the less specific antibody. With the TRH-specific antibody, TRH-LI was identified only in 3 samples, 2 of which contained exceedingly high concentrations (40 and 96 pg/mg tissue). In the latter 2 samples, prepro-TRH messenger ribonucleic acid was identified by Northern blot analysis, but not in the control tissue sample of a patient without pituitary disease and also not in the other adenomas analyzed by this technique. Transcripts of the TRH receptor were almost undetectable in all adenomas analyzed. For the TRH-degrading ectoenzyme, a potential regulator of TRH signals at adenohypophyseal target sites, transcripts were significantly expressed only in the TRH-producing adenomas. We conclude that the TRH-signaling elements examined are, in general, not directly involved in the mechanisms causing paradoxical GH secretion in acromegalic patients.

Involvement of thyroid hormones in the effect of intracerebroventricular leptin infusion on uncoupling protein-3 expression in rat muscle

We have shown previously that continuous (6 days) intracerebroventricular (ICV) leptin infusion in normal rats resulted in decreases in food intake and body weight. A reduction of food intake imposed on control rats (pair-feeding), aimed at mimicking leptin-induced hyperphagia, produced a marked decrease in the expression of muscle uncoupling protein-3 (UCP-3), whereas ICV infusion of leptin prevented such a decrease in UCP-3. To investigate an involvement of thyroid hormones in this effect of leptin, plasma levels of these hormones were determined in ICV leptin-infused, ICV vehicle-infused ad libitum fed or pair-fed controls. ICV leptin infusion and pair-feeding resulted in decreased plasma thyroid-stimulating hormone (TSH) and T4 levels relative to ad libitum fed controls. ICV leptin infusion maintained plasma levels of T3, but the levels were decreased by pair-feeding. The activity of the enzyme (hepatic 5'-monodeiodinase) responsible for T4/T3 conversion was measured. In the leptin-infused group, the activity of 5'-monodeiodinase was maintained at the values measured in ad libitum fed rats; in pair-fed rats, activity was reduced. Thus, conversion of T4 to T3 is decreased by pair-feeding, whereas such is not the case during leptin infusion. To further substantiate an involvement of thyroid hormones in the effect of leptin on muscle UCP-3 expression, hypothyroid rats were ICV infused with leptin or vehicle. It was observed that in hypothyroid rats, ICV leptin was unable to maintain muscle UCP-3 expression at values measured in ad libitum fed controls. These results suggest that central leptin stimulates T3 production via an activation of T4 to T3 conversion, and that this stimulation could be responsible for the effect of leptin on muscle UCP-3 expression. Thyroid hormones could thus be important mediators of the effect of leptin on energy expenditure.

Colorectal complications following cardiac surgery. Six-year experience

PURPOSE

This study was undertaken to assess colorectal complications following cardiopulmonary bypass surgery.

METHOD

This is a retrospective review of 5,801 patients who underwent 5,801 cardiopulmonary bypass procedures from 1985 to 1991. Patients were evaluated for type of bypass procedure, postoperative colorectal complications, age, sex, bypass time, aortic cross-clamp time, elective vs. emergency cases, uses of intra-aortic balloon pump, perioperative hypotension, and use of vasopressors. Statistical analysis was performed using chi-squared analysis and Student's t-test.

RESULTS

Nineteen of the 5,801 patients developed 19 colorectal complications, a prevalence of 0.3 percent for the initial hospital stay following bypass surgery. Mortality in those with complications was 37 percent (7/19). Of the 19 complications, 9 (47 percent) followed coronary artery bypass grafting, whereas 10 (53 percent) followed valve replacement or combined coronary artery bypass grafting with other cardiac procedures. Five (26 percent) of the complications followed emergency cases, whereas 14 (74 percent) followed elective cases. Average age of those with complications was 69.8 years, compared with 63.2 years for those without complications. Average aortic cross-clamp time for those with complications was 71 +/- 25 minutes; pump time was 106 +/- 34 minutes. That was significantly higher than in those without complications. Nine (47 percent) patients with complications required vasopressors during the perioperative period, whereas eight (42 percent) suffered prolonged hypotension (systolic blood pressure, < 90 mmHg).

CONCLUSIONS

It appears that increased age, valve replacement, or combined cardiac procedures, emergency procedures, and prolonged aortic cross-clamp and bypass pump times are risk factors for development of colorectal complications. Hypoperfusion, as suggested by prolonged pump times, clamp times, and emergency procedures may be a possible cause for development of colorectal complications.

Conditions for engraftment of human acute myeloid leukemia (AML) in SCID mice

Transplantation of human AML into severe combined immunodeficient (SCID) mice provides a useful experimental model but graft failures have been reported. We investigated the influence of a number of factors on the outgrowth of AML in the SCID mouse bone marrow (BM). The transplantation route and total body irradiation (TBI) were examined using the cell line HL-60 as a model for AML. The role of graft size and recombinant human IL-3 (IL-3) were investigated with patient samples of AML cells. Intravenous transplantation was demonstrated to be superior to intraperitoneal transplantation. Pretransplant conditioning resulted in a dose-dependent increase of AML growth in the SCID mouse. Cell dose titrations ranging from 3 x 10(7) - 3.6 x 10(5) AML cells i.v. per mouse revealed a minimum of 1.1 x 10(6) required for reproducible engraftment. Earlier and more extensive infiltration by human AML cells was seen following injection of greater cell numbers. IL-3 given post-transplantation SCID mouse recipients, promoted AML growth in three cases, whereas a fourth AML cell specimen also grew without support of IL-3. In vitro growth factor responsiveness of AML cells to IL-3 did not predict IL-3 dependence of AML growth in vivo.

Confirmational analysis of beta-agonists by cryotrapping gas chromatography-Fourier transform infrared spectrometry

Cryotrapping gas chromatography-Fourier transform infrared spectrometry has been used for confirmation analysis of the beta-agonists clenbuterol, salbutamol, mabuterol, bromobuterol, cimaterol, cimbuterol and mapenterol in urine and liver samples of veal calves, subsequent to selected ion detection gas chromatography-mass spectrometry. Samples have been analysed as their trimethylsilyl and methylboronate derivatives. Methylboronate derivatives yielded strongly diminished chemical background and interference levels in the infrared chromatograms of standards and samples. The limit of identification for methylboronate derivatives was at the low ppb level in incurred samples. The similarity of analyte and reference spectra, together with the retention time, was found to be a useful criterion for confirmation of unknown compounds.

Relation of plasma coagulation factor VII and fibrinogen to carotid artery intima-media thickness

Plasma clotting factor VII and plasma fibrinogen have been claimed as independent risk factors for occlusive cardiovascular disease. The aim of this study was to investigate whether these coagulation parameters affect early atherosclerosis, additional to their possible effect on arterial thrombosis. We used high-resolution quantitative ultrasonography to measure carotid intima-media thickness in 121 healthy volunteers, aged 18 to 56 years. It has previously been demonstrated that an increased artery wall thickness is seen in advanced atherosclerosis. To validate our methodology for relatively young individuals, we assessed the association of intima-media thickness with the risk-factor status of our subjects, by including classical cardiovascular risk factors, e.g. age, sex, serum cholesterol, smoking habits and blood pressure. Thereafter, we studied the effect of factor VII and fibrinogen plasma levels on carotid intima-media thickness, as well as that of polymorphisms of the factor VII and fibrinogen genes. All classical risk factors except smoking and family history were associated with intima-media thickness. When adjusted for by multivariate linear regression analysis, age, blood pressure and cholesterol appeared to be independent determinants of intima-media thickness. Factor VII and fibrinogen levels showed no association in multivariate analysis with intima-media thickness. We conclude that artery wall thickness measurement by ultrasound is a useful tool to investigate the role of clotting factors in early atherosclerosis. Factor VII and fibrinogen levels in young and middle-aged volunteers have no association with early artherosclerotic vessel wall changes.

Metabolic and antioxidant enzyme activities in the diaphragm: effects of acute exercise

Disruption of cellular constituents including inhibition or "downregulation" of metabolic enzyme activity has been associated with free radical stress in locomotor muscle with acute, strenuous exercise. However, the effects of acute, strenuous exercise on important metabolic and antioxidant enzyme activity levels in the diaphragm are unknown. Twenty 4-month-old and twenty 24-month-old female Fischer-344 rats were divided at random into young exercised (YE; n = 10)/old exercised (OE; n = 10); young control (YC; n = 10)/old control (OC; n = 10) groups. Animals in both young and old exercise groups ran on a treadmill (10% uphill grade) for 40 min at approximately 75% of age group VO2 max. Immediately following the treadmill run, both exercise and control groups were euthanized with sodium pentobarbital. Costal (COD) and crural diaphragm (CRD) were quickly removed and frozen in liquid nitrogen. Lipid peroxidation was significantly increased (P < 0.05) in COD of YE vs. YC rats. Activity of the antioxidant enzyme glutathione peroxidase (GPX) was unaltered in the diaphragm by acute exercise (P > 0.05) in both age groups. There was a significant increase in superoxide dismutase (SOD) activity with exercise (P < 0.05). Post-hocs revealed SOD activity was approximately 20% greater (P = 0.066) in YE CRD only. Activities of the metabolic enzymes phosphofructokinase (PFK), succinate dehydrogenase (SDH), and citrate synthase (CS) were not affected by acute exercise in YE or OE. Strenuous exercise resulted in a small trend towards a decrease in 3-hydroxyacyl-CoA dehydrogenase (HADH) activity in YE COD (P = 0.115) and YE CRD (P = 0.082). We conclude that the employed bout of exercise induces some free radical stress, while metabolic enzymes are protected, in the diaphragm.

Acute exercise and skeletal muscle antioxidant and metabolic enzymes: effects of fiber type and age

Inhibition of metabolic enzyme activity has been associated with free radical stress in locomotor muscle with prolonged or intense exercise. However, it is not known whether such alterations with acute exercise in skeletal muscle are influenced by muscle fiber type or age. Twenty 4-mo-old and twenty 24-mo-old female Fischer-344 rats were divided at random into young exercised (YE; n = 10), old exercised (OE; n = 10), young control (YC; n = 10), and old control (OC; n = 10) groups. Animals in both YE and OE groups ran on a treadmill (10% uphill grade) for 40 min at approximately 75% of each age-group's maximal O2 consumption. Immediately after the treadmill run, white gastrocnemius (WG), red gastrocnemius (RG), and soleus (SOL) muscles were removed and quick-frozen in liquid nitrogen. Malondialdehyde was significantly increased (P < 0.05) in RG of YE vs. YC rats. Glutathione peroxidase activity was significantly elevated (P < 0.05) in the WG of YE rats. Analysis of variance revealed a significant over-all increase in superoxide dismutase activity with exercise. Activities of phosphofructokinase (PFK), citrate synthase, succinate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase were unchanged (P > 0.05) with acute exercise in the SOL. However, PFK activity was decreased in the WG by 60% in OE but only 33% in YE, and in the RG by 41% in OE but only 21% in YE. We conclude that maximal glycolytic flux in the gastrocnemius may be adversely affected by acute exercise, and this effect was more pronounced in the 24-mo-old group.

Liquid chromatographic purification and detection of anabolic compounds

The role of liquid chromatography within methods of analysis for steroids, related compounds and beta-agonists in biological samples is discussed. Special attention is given to the application of liquid chromatography in sample preparation and extract clean-up. Different forms of liquid chromatography, including immunoaffinity chromatography, are compared and evaluated. Methods for confirmation based on gas chromatography-mass spectrometry and cryotrapping Fourier transform infrared spectrometry are discussed.

Lipoamide dehydrogenase from Azotobacter vinelandii: site-directed mutagenesis of the His450-Glu455 diad. Spectral properties of wild type and mutated enzymes

Three amino acid residues in the active site of lipoamide dehydrogenase from Azotobacter vinelandii were replaced by other residues. His450, the active-site base, was changed into Ser, Tyr and Phe. Pro451, in cis conformation, was changed into Ala. Glu455 was replaced with Asp and Gln. Absorption, fluorescence and CD spectroscopy of the mutated enzymes in their oxidized state (Eox) showed only minor changes with respect to the wild-type enzyme, whereas considerable changes were observed in the spectra of the two-electron-reduced (EH2) species of the enzymes upon reduction by the substrate dihydrolipoamide. Differences in extent of reduction of the flavin by NADH indicate that the redox potential of the flavin is altered by the mutations. Enzyme Pro451----Ala [corrected] showed the greatest deviation from wild type. The enzyme is very easily over-reduced to the four-electron reduced state (EH4) by dihydrolipoamide. This is probably due to a change in the backbone conformation caused by the cis-trans conversion. From studies on the pH dependence of the thiolate charge-transfer absorption and the relative fluorescence of EH2 of the enzymes, it is concluded that mutation of His450 results in a relatively simple and easily interpreted distribution of electronic species at the EH2 level. For all three His450-mutated enzymes an apparent pKa1 near 5.5 is calculated that is assigned to the interchange thiol. A second apparent pKa2 is calculated of 6.9, 7.5 and 7.1 for the His450----Phe, -Ser and -Tyr enzymes, respectively, and signifies the deprotonation of the tautomeric equilibrium between the interchange and charge-transfer thiols. The difference in apparent pKa2 values between the His450-mutated enzymes is explained by changes in micropolarity. At the EH2 level the wild-type enzyme consists of multiple electronic forms as reported for the Escherichia coli enzyme [Wilkinson, K. D. and Williams C. H. Jr (1979) J. Biol. Chem. 254, 852-862]. Based on the results obtained with the His450-mutated enzymes, it is concluded that the lowest pKa is associated with the interchange thiol. A model for the equilibrium species of the wild-type enzyme at the EH2 level is presented which takes three pKa values into account. The results of the pH dependence of the electronic species at the EH2 level of Glu455-mutated enzymes essentially follow the model proposed for the wild-type enzyme. However mutation of Glu455 shifts the tautomeric equilibrium of EH2 in favor of the charge-transfer species.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for thyrotropin-releasing hormone and glucocorticoid receptor-immunoreactive neurons in various preoptic and hypothalamic nuclei of the male rat

Neurons containing thyrotropin-releasing hormone (TRH) and glucocorticoid receptor (GR) immunoreactivity (IR) were demonstrated by a two-colour immunoperoxidase method in coronal cryotome sections of the preoptic region and the hypothalamus of the male rat brain. All the TRH-IR neurons (TRH-IR) located in the dorsal hypothalamus - medial and dorsal parvocellular parts of the paraventricular hypothalamic nucleus and the dorsomedial hypothalamic nucleus - and in the anterior periventricular hypothalamic nucleus were strongly GR-IR. The TRH-IR neurons of the medial preoptic area, the perifornical nucleus and the medial tuberal area were mostly weakly GR-IR and some lacked GR-IR. These data indicate a differential regulation of diencephalic TRH-IR neurons by glucocorticoids. They also imply that the inhibitory effect of glucocorticoids on TSH secretion may involve a direct inhibition of TRH synthesis and/or release by a nuclear action in the TRH-IR nerve cells of the paraventricular hypothalamic nucleus projecting to the median eminence.

An ultrastructural study of 5-hydroxytryptamine-, thyrotropin-releasing hormone- and substance P-immunoreactive axonal boutons in the motor nucleus of spinal cord segments L7-S1 in the adult cat

The distribution and fine structure of 5-hydroxytryptamine-, thyrotropin-releasing hormone- and substance P-immunoreactive synaptic boutons and varicosities were studied in the motor nucleus of the spinal cord segments L7-S1 in the cat, using the peroxidase-antiperoxidase immunohistochemical technique and analysis of ultrathin serial sections. The 5-hydroxytryptamine-, thyrotropin-releasing hormone- and substance P-immunoreactive boutons had a similar ultrastructural appearance as judged from serial section analysis. The boutons could be classified into two types on the basis of their vesicular content, with one type containing a large number of small agranular vesicles together with only a few, if any large granular vesicles, while the other type contained a large number of large granular vesicles in addition to small agranular vesicles. The vesicles were spherical or spherical-to-pleomorphic. Postsynaptic dense bodies (Taxi bodies) were occasionally observed in relation to all three types of immunoreactive boutons, which almost invariably formed synaptic junctions with dendrites. Judged by the calibre of the postsynaptic dendrites, the boutons were preferentially distributed to the proximal dendritic domains of motoneurons. In one case, a substance P-immunoreactive bouton formed an axosomatic synaptic contact. In addition to synaptic boutons, 5-hydroxytryptamine-, thyrotropin-releasing hormone- and substance P-immunoreactive axonal varicosities containing a large number of large granular and small agranular vesicles but lacking any form of conventional synaptic contact were observed. Such varicosities were either directly apposing surrounding neuronal elements or separated from the neurons by thin glial processes. The origin of the immunoreactive boutons was not traced, but it was thought likely that the main source of the boutons was neurons with their cell bodies located in the medullary raphe nuclei.

Thyrotropin releasing hormone (TRH)-immunoreactive cell groups in the rat central nervous system

Using a paraformaldehyde-picric acid-glutaraldehyde-containing fixative and treatment of the tissue with sodium borohydride, numerous and widespread TRH-immunoreactive cell bodies were observed in the central nervous system of colchicine-treated rats, including the olfactory bulb, cortical and hippocampal areas, the caudate nucleus and other subcortical areas, many hypothalamic nuclei, the periaqueductal central gray, pontine nuclei, medulla oblongata and the dorsal horn of the spinal cord. Most of these cells could not be visualized with the same antiserum when conventional fixation methods based on formalin alone were used. The present findings suggest that TRH systems are considerably more extensive than hitherto assumed.

Lymphoid tissue of the normal fallopian tube--a form of mucosal-associated lymphoid tissue (MALT)?

Mucosal-associated lymphoid tissue (MALT) is a specialized form of peripheral lymphoid tissue which is found in mucosal surfaces directly or indirectly exposed to the environment. Using immunohistological labeling techniques and electron microscopy, we have explored the possibility that MALT exists in the normal fallopian tube. Immunohistological analysis has demonstrated a striking degree of uniformity in the phenotype of intraepithelial lymphocytes with a predominance of T-lymphocytes of T-cytotoxic/suppressor subtype. Occasional intraepithelial macrophages are also present, but B-cells, T-helper cells, and natural killer cells are absent or are rarely found in the epithelium. Electron microscopy has provided morphological evidence of an interaction between epithelial cells and intraepithelial lymphocytes. The opposing plasma membranes of these two cell types are arranged in the form of complex interdigitations and laminations. These striking arrangements substantially increase the total area of contact between the two cell types. We conclude that MALT does exist in the fallopian tube and that epithelial cells form an integral part of the system. A hypothetical view of the relationship between these cell types is presented.

Reliable routine method for the determination of antidepressant drugs in plasma by high-performance liquid chromatography

We describe a rapid and reliable method using high-performance liquid chromatography for the simultaneous measurement of plasma concentrations of currently prescribed antidepressants and their main metabolites (amitriptyline, nortriptyline, trans-10-hydroxy-nortriptyline, clomipramine, desmethylclomipramine, imipramine, desipramine, zimeldine, norzimeldine, doxepin, desmethyldoxepin, trimipramine and mianserin). The method involves a single extraction of plasma at pH 10.1 with hexane-acetonitrile (98:2), solvent transfer to and evaporation in a disposable glass tube and subsequent chromatography of the residue on a CN bonded-phase column using acetonitrile-methanol-phosphate buffer (pH 7.0) as mobile phase. Protriptyline is used as the internal standard. Calibration curves remain linear up to at least 200 micrograms/l, detection limits are 5 micrograms/l, absolute recoveries are over 92%, and precision (coefficient of variation) is 6.9%. Norzimeldine and 10-hydroxynortriptyline show lower recoveries, protriptyline and 10-hydroxynortriptyline higher detection limits. Adsorption to glassware and chemical decomposition during analysis are shown to be negligible. Psychoactive and other drugs frequently prescribed in combination with anti-depressants have been tested for their chromatographic properties under the same conditions.