Pregnancy and melanoma: a European-wide survey to assess current management and a critical literature overview

BACKGROUND

Management of melanoma during pregnancy can be extremely challenging. The reported incidence of melanoma in pregnancy ranges from 2.8 to 5.0 per 100 000 pregnancies. There are no guidelines for the management of melanoma during pregnancy.

METHODS

The survey was designed to investigate the opinions of melanoma physicians on decision making in relation to pregnancy and melanoma. A clinical scenario-based survey on management of pregnancy in melanoma was distributed all over Europe via the membership of the EORTC and other European melanoma societies.

RESULTS

A total of 290 questionnaires were returned with a larger participation from southern Europe. A large heterogeneity was found for the answers given in the different clinical scenarios with 50% of the answers showing discordance, especially regarding sentinel lymph node biopsy during pregnancy. Discordant answers were also found for the counselling of women about a potential delay in getting pregnant after a high-risk melanoma (35% for a 2 year wait minimum vs. 57% no waiting needed), while for thin melanomas, as expected, there was more concordance with 70% of the physicians recommending no delay. Fifteen per cent of physicians recommended an abortion in stage II melanoma during the third month of pregnancy. Twenty per cent of the responders advised against hormonal replacement therapy in melanoma patients.

CONCLUSIONS

The management of melanoma during pregnancy varies widely in Europe. At present, there is a lack of consensus in Europe, which may lead to very important decisions in women with melanoma, and guidelines are needed.

Is farm-related job title an adequate surrogate for pesticide exposure in occupational cancer epidemiology?

OBJECTIVES

Accurate assessment of exposure is a key factor in occupational epidemiology but can be problematic, particularly where exposures of interest may be many decades removed from relevant health outcomes. Studies have traditionally relied on crude surrogates of exposure based on job title only, for instance farm-related job title as a surrogate for pesticide exposure.

METHODS

This analysis was based on data collected in Western Australia in 2000-2001. Using a multivariate regression model, we compared expert-assessed likelihood of pesticide exposure based on detailed, individual-specific questionnaire and job specific module interview information with reported farm-related job titles as a surrogate for pesticide exposure.

RESULTS

Most (68.8%) jobs with likely pesticide exposure were farm jobs, but 78.3% of farm jobs were assessed as having no likelihood of pesticide exposure. Likely pesticide exposure was more frequent among jobs on crop farms than on livestock farms. Likely pesticide exposure was also more frequent among jobs commenced in more recent decades and jobs of longer duration. Our results suggest that very little misclassification would have resulted from the inverse assumption that all non-farming jobs are not pesticide exposed since only a very small fraction of non-agricultural jobs were likely to have had pesticide exposure.

CONCLUSIONS

Classification of all farm jobs as pesticide exposed is likely to substantially over-estimate the number of individuals exposed. Our results also suggest that researchers should pay special attention to farm type, length of service and historical period of employment when assessing the likelihood of pesticide exposure in farming jobs.

Inorganic nitrogen and phosphorus in Sierran forest O horizon leachate

High in situ concentrations of inorganic N and P have been reported in overland/litter interflow from Sierran forests, indicating that these nutrients are derived from the forest floor O horizons. To test this hypothesis, forest floor monoliths consisting of the combined O(e) and O(i) horizons were collected near the South Shore of Lake Tahoe, Nevada, for leaching experiments. Three monoliths were left intact, and three were hand-separated according to horizon for a total of three treatments (combined O(e)+O(i), O(e) only, and O(i) only) by three replications. Samples were randomized and placed into lined leaching bins. Initial leaching consisted of misting to simulate typical early fall precipitation. This was followed by daily snow applications and a final misting to simulate spring precipitation. Leachate was collected, analyzed for NH(4)(+)-N, NO(3)(-)-N, and PO(4)(3-)-P, and a nutrient balance was computed. There was a net retention of NH(4)(+)-N, but a net release of both NO(3)(-)-N and PO(4)(3-)-P, and a net release of inorganic N and P overall. Total contributions (mg) of N and P were highest from the O(e) and O(e)+O(i) combined treatments, but when expressed as per unit mass, significantly (p < 0.05) higher amounts of NO(3)(-)-N and PO(4)(3-)-P were derived from the O(i) materials. The nutrients in forest floor leachate are a potential source of biologically available N and P to adjacent surface waters. Transport of these nutrients from the terrestrial to the aquatic system in the Lake Tahoe basin may therefore play a part in the already deteriorating clarity of the lake.

Evidence of thymic reconstitution after highly active antiretroviral therapy in HIV-1 infection

OBJECTIVES

We aimed to provide evidence of thymic reconstitution after highly active antiretroviral therapy (HAART) in HIV-1 infected patients and to correlate this with the restoration of peripheral naïve T cells.

METHODS

Positron emission tomography (PET) enables definitive evidence of thymic activity, indicating functional potential. In this case study, a single patient who initiated HAART demonstrated reconstitution of the naïve T-cell pool and underwent thymic PET scans at baseline and 2 and 6 months following initiation of therapy. Two patients who failed to demonstrate such reconstitution acted as controls. These patients (mean age 27 years) had chronic HIV infection with low CD4 T-cell counts (mean 82, range 9-160 cells/microL blood). Increased function of the thymus visualized by PET was correlated with phenotypic changes in CD4 and CD8 T cells in the periphery measured by flow cytometry, and with numbers of recent thymic emigrants measured by quantification of the numbers of T-cell receptor excision circles (TRECs) in peripheral cells.

RESULTS

In one patient, clear correlations could be drawn between visible activity within the thymus, as measured by increased [F18]fluorodeoxyglucose (FDG) uptake, and regeneration of naïve CD4 (CD45RA/CD62L) T cells, increased numbers of CD4 T cells, controlled viraemia and increased numbers of recent thymic emigrants. A second patient displayed no increase in peripheral CD4 count and no increase in thymic activity. The third patient elected to stop therapy following the 2-month time point.

CONCLUSIONS

The use of PET suggests that thymic activity may increase after HAART, indicating that the thymus has the potential to be functional even in HIV-1 infected persons with low CD4 T-cell counts.

The sociodemographic profile, risk categories and prevalence of HIV infection among people attending a London same-day testing clinic, 2000-2001

The objectives were to determine the sociodemographic profile, risk category, and prevalence of HIV infection amongst people attending a confidential clinic providing counselling, medical advice and results of HIV antibody testing on the same day of consultation. Data were collected on all 1749 individuals attending the same-day HIV testing clinic at the Royal Free Hospital, London and proceeding to HIV testing between June 2000 and May 2001. One thousand, one hundred and forty-eight men and 601 women (mean age 33.3 years) were tested for HIV antibodies. The primary risk for HIV infection was heterosexual contact (69.9%; 1224/1749) and homosexual contact (27.7%; 485/1749). Fifty individuals tested HIV-positive (42 men and eight women). HIV seroprevalence was 2.8% (50/1749) and was highest among men who reported risk through homosexual contact (6.2%; 30/485). The rates for heterosexual men and women were 1.8% (12/648) and 1.4% (8/576), respectively, though they were highest among Black Caribbean (12%; 3/25) and Black African attendees from sub-Saharan African countries (11.2%; 18/160). Of the total number attending the clinic, more than half (56%; 981/1749) had previously been tested and received a negative test result. Of the fifty HIV antibody-positive individuals, 26%, (13) had previously received a negative result and had all reported risk through homosexual contact. Thirty of the HIV antibody-positive individuals were asymptomatic, 14 were symptomatic and three were diagnosed with an AIDS-defining condition. Half of all HIV-positive attendees (51.2%; 22/43) presented at the time of testing with CD4 cell counts below the normal range (>400x10(6)/l). The high HIV seroprevalence among homosexual men, some of whom had previously tested negative, suggests that HIV prevention strategies used within this group may need to be reassessed. The continuing high HIV seroprevalence among individuals from African countries suggests that this population require specific targeting for HIV risk reduction and information on the advantages of early diagnosis and treatment.

Non-HLA gene polymorphisms in juvenile rheumatoid arthritis

A substantial amount of work has gone into elucidating the non-HLA genetic associations in JRA. In this paper, we attempt to provide an overview of this body of knowledge. Direct comparison of the different studies is difficult. Different ethnic populations, different JRA/JIA subgroups, and different systems of nomenclature and classification all impose various limitations. Adding to the complexity is the polygenic nature of chronic childhood arthritis. Family based studies will be necessary to overcome ethnicity related issues. A candidate gene approach complemented by genome wide screen data will hopefully advance our knowledge of the genetics of JRA.

Effect of APOE genotype on microvascular basement membrane in Alzheimer's disease

APOE4 homozygosity has been associated with an increased risk of sporadic Alzheimer's disease through a mechanism, which has yet to be defined. Recent evidence has suggested that microvascular basement membrane injury may be a critical factor in the pathogenesis of AD-related dementia. In previous studies, we have shown that the synaptic organizing protein agrin can be found in neurons, and is a major component of the brain microvascular basement membrane. Here, we compare the basement membrane surface area of cortical microvasculature in AD brains by staining with an anti-agrin antibody. Quantitative morphometric analysis was used to determine the mean basement area (micro(2)) of prefrontal cortical microvessels. An average of 10 capillaries was measured in each of 35 cases of AD genotyped for APOE status. APOE4,4 homozygotes had smaller capillary basement membrane areas (17.4 micro(2))+/-6.2) than APOE3,3 homozygotes (26.9 micro(2)+/-6.5), p<0.001. The capillary basement membrane areas (CBMA) of heterozygotes APOE3,4 did not differ significantly from APOE3,3 or APOE4,4. Braak stage did not contribute significantly to CBMA. However, a preliminary analysis suggests an interaction between APOE4,4 and Braak V-VI producing smaller CBMA, a finding which needs to be confirmed with a larger sample. These data support the hypothesis that APOE4,4 is associated with thinning of the microvascular basement membrane in Alzheimer's disease.

Effective targeting of solid tumors in patients with locally advanced cancers by radiolabeled pegylated liposomes

The biodistribution and pharmacokinetics of (111)In-DTPA-labeled pegylated liposomes (IDLPL) were studied in 17 patients with locally advanced cancers. The patients received 65-107 MBq of IDLPL, and nuclear medicine whole body gamma camera imaging was used to study liposome biodistribution. The t(1/2beta) of IDLPL was 76.1 h. Positive tumor images were obtained in 15 of 17 studies (4 of 5 breast, 5 of 5 head and neck, 3 of 4 bronchus, 2 of 2 glioma, and 1 of 1 cervix cancer). The levels of tumor liposome uptake estimated from regions of interest on gamma camera images were approximately 0.5-3.5% of the injected dose at 72 h. The greatest levels of uptake were seen in the patients with head and neck cancers [33.0 +/- 15.8% ID/kg (percentage of injected dose/kg)]. The uptake in the lung tumors was at an intermediate level (18.3 +/- 5.7% ID/kg), and the breast cancers showed relatively low levels of uptake (5.3 +/- 2.6% ID/kg). These liposome uptake values mirrored the estimated tumor volumes of the various tumor types (36.2 +/- 18.0 cm3 for squamous cell cancer of the head and neck, 114.5 +/- 42.0 cm3 for lung tumors, and 234.7 +/- 101.4 cm3 for breast tumors). In addition, significant localization of the liposomes was seen in the tissues of the reticuloendothelial system (liver, spleen, and bone marrow). One patient with extensive mucocutaneous AIDS-related Kaposi sarcoma was also studied according to a modified protocol, and prominent deposition of the radiolabeled liposomes was demonstrated in these lesions. An additional two patients with resectable head and neck cancer received 26 MBq of IDLPL 48 h before undergoing surgical excision of their tumors. Samples of the tumor, adjacent normal mucosa, muscle, fat, skin, and salivary tissue were obtained at operation. The levels of tumor uptake were 8.8 and 15.9% ID/kg, respectively, with tumor uptake exceeding that in normal mucosa by a mean ratio of 2.3:1, in skin by 3.6:1, in salivary gland by 5.6:1, in muscle by 8.3:1, and in fat by 10.8:1. These data strongly support the development of pegylated liposomal agents for the treatment of solid tumors, particularly those of the head and neck.

A double-blind investigation of the potential systemic absorption of isotretinoin, when combined with chemical sunscreens, following topical application to patients with widespread acne of the face and trunk

This study assessed the systemic absorption of isotretinoin and its metabolites, during a 4-week application of a cream containing 0.1% isotretinoin and chemical sunscreens, compared with a 4% benzoyl peroxide cream, in patients with acne on the face and trunk. Blood was drawn at weeks 0, 1, 2, 3 and 4 and at 96 h post-treatment. Plasma levels of isotretinoin (13-cis-retinoic acid) and tretinoin (all-trans-retinoic acid) were quantified by liquid chromatography with tandem mass spectrometry and the presence of their combined 4-oxo metabolites were monitored from the peak area ratios observed. The isotretinoin group showed no statistically or clinically significant increases in plasma retinoid levels and mean levels did not exceed +/-2 SD of the mean pre-treatment values, indicating that endogenous levels were not being exceeded. No significant differences were detected between the isotretinoin group and the 4% benzoyl peroxide group. These findings indicated that retinoid absorption from a cream containing 0.1% isotretinoin and chemical sunscreens was clinically insignificant, when applied to patients with widespread acne.

Comparison of myocardial contrast echocardiography with NC100100 and (99m)Tc sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

OBJECTIVE

To determine whether myocardial contrast echocardiography (MCE) following intravenous injection of perfluorocarbon microbubbles permits identification of resting myocardial perfusion abnormalities in patients who have had a previous myocardial infarction.

PATIENTS AND INTERVENTIONS

22 patients (mean (SD) age 66 (11) years) underwent MCE after intravenous injection of NC100100, a novel perfluorocarbon containing contrast agent, and resting (99m)Tc sestamibi single photon emission computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect.

RESULTS

Among the 203 normally contracting segments, 151 (74%) were normally perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptake was mainly found among normally contracting segments from the inferior wall. By contrast, with MCE poor myocardial opacification was noted essentially among the normally contracting segments from the anterior and lateral walls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects by SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities were seen more frequently among akinetic than hypokinetic segments. MCE correctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exclusion of segments with attenuation artefacts (defined as abnormal myocardial opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of the detection of SPECT perfusion defects by MCE.

CONCLUSIONS

The data suggest that MCE allows identification of myocardial perfusion abnormalities in patients who have had a previous myocardial infarction, provided that regional wall motion is simultaneously taken into account.

A placebo-controlled clinical trial to compare a gel containing a combination of isotretinoin (0.05%) and erythromycin (2%) with gels containing isotretinoin (0.05%) or erythromycin (2%) alone in the topical treatment of acne vulgaris

PURPOSE

To compare the clinical benefit of isotretinoin (0.05%) and erythromycin (2%) gels alone and in combination (Isotrexintrade mark) in acne patients.

PROCEDURE

The study was a randomised placebo-controlled trial in acne patients who should benefit from topical therapy.

RESULTS

All treatment groups except placebo produced a time-related reduction in lesion counts, with the combined therapy producing the largest mean decrease. Between-group comparisons showed several significant differences.

CONCLUSION

Isotrexin was significantly better than placebo at all time points for inflamed and total lesions, and was better than isotretinoin at week 4. Side-effects were minimal.

Development of the neuromuscular junction: genetic analysis in mice

Formation of the skeletal neuromuscular junction is a multi-step process that requires communication between the nerve and muscle. Studies in many laboratories have led to identification of factors that seem likely to mediate these interactions. 'Knock-out' mice have now been generated with mutations in several genes that encode candidate transsynaptic messengers and components of their effector mechanisms. Using these mice, it is possible to test hypotheses about the control of synaptogenesis. Here, we review our studies on neuromuscular development in mutant mice lacking agrin alpha CGRP, rapsyn, MuSK, dystrophin, dystrobrevin, utrophin, laminin alpha 5, laminin beta 2, collagen alpha 3 (IV), the acetylcholine receptor epsilon subunit, the collagenous tail of acetylcholinesterase, fibroblast growth factor-5, the neural cell adhesion molecule, and tenascin-C.

Human papillomavirus type 11 neutralization in the athymic mouse xenograft system: correlation with virus-like particle IgG concentration

Neutralization of virus is likely to be necessary for development of an effective prophylactic vaccine against genital human papillomavirus (HPV) infection. Two New Zealand white rabbits were immunized with purified HPV type 11 (HPV 11) virions in Freund's adjuvant. An enzyme linked immunoassay (ELISA) was used to determine the quantity of IgG which recognized the HPV 11 major capsid protein (L1 protein) virus-like particles (VLPs) in the two anti-HPV 11 sera (serum A and serum B). The concentration of HPV 11 L1 VLP-specific IgG in the A and B sera were determined to be 37 and 90 micrograms per ml, respectively. The A and B sera were used in neutralization experiments in the athymic mouse xenograft system with known quantities of purified HPV 11 virions. The concentration of HPV 11 L1 VLP-specific IgG required to neutralize HPV 11 was determined for each antiserum. This concentration of IgG was approximately 700 to 900 ng per ml. This study demonstrates a positive correlation between the level of HPV 11 L1 VLP-specific IgG in animals immunized with HPV 11 virions and neutralization of HPV 11 in the athymic mouse model. Further studies are needed 1) to determine if sera or genital secretions from other species are neutralizing in the athymic mouse xenograft system, and 2) to determine if the VLP ELISA can be used as a reliable substitute for more cumbersome neutralization assays.

Efficiency and productivity of a sheathed fiberoptic sigmoidoscope compared with a conventional sigmoidoscope

PURPOSE

The aim of this study was to measure and compare time and productivity between a new sheathed flexible sigmoidoscope and a traditional fiberoptic flexible sigmoidoscope relative to labor and cost analysis.

METHODS

Two flexible sigmoidoscopes, the Vision Sciences sigmoidoscope using a protective sheath covering requiring removal and replacement between procedures and a conventional flexible sigmoidoscope requiring meticulous cleaning using a washer and high-level disinfection, were compared. Sigmoidoscope preparation was defined as the average time between the procedures (reprocessing, start to finish) and was measured by an independent nonmedical timekeeper JG). The parameter recorded was scope reprocessing time.

RESULTS

Ten procedures were performed using the sheathed flexible sigmoidoscope system compared with nine using a conventional sigmoidoscope. Scope performance and endoscopic visualization for both systems were comparable. The average reprocessing time was 46.8 minutes for the conventional sigmoidoscope vs. 4.9 minutes for the sheathed sigmoidoscope (P < 0.0001). The average time saved was 9.5 times greater with the sheathed flexible sigmoidoscope system than with the conventional sigmoidoscope.

CONCLUSION

The almost tenfold difference in the time saved using the sheathed flexible sigmoidoscope system represents increased productivity and potentially decreased overall labor cost. By reducing endoscope turnover time, this new sheathed system can reduce or even eliminate the need for backup endoscopes and endoscope washers and potentially allow better use of nursing staff.

ECAT ART - a continuously rotating PET camera: performance characteristics, initial clinical studies, and installation considerations in a nuclear medicine department

Advances in fully three-dimensional (3D) image reconstruction techniques have permitted the development of a commercial, rotating, partial ring, fully 3D positron emission tomographic (PET) scanner, the ECAT ART. The system has less than one-half the number of bismuth germanate detectors compared with a full ring scanner with the equivalent field of view, resulting in reduced capital cost. The performance characteristics, implications for installation in a nuclear medicine department, and clinical utility of the scanner are presented in this report. The sensitivity (20 cm diameterx20 cm long cylindrical phantom, no scatter correction) is 11400 cps.kBq-1.ml-1. This compares with 5800 and 40500 cps.kBq-1.ml-1 in 2D and 3D respectively for the equivalent full ring scanner (ECAT EXACT). With an energy window of 350-650 keV the maximum noise equivalent count (NEC) rate was 27 kcps at a radioactivity concentration of approximately 15 kBq.ml-1 in the cylinder. Spatial resolution is approximately 6 mm full width at half maximum on axis degrading to just under 8 mm at a distance of 20 cm off axis. Installation and use within the nuclear medicine department does not appreciably increase background levels of radiation on gamma cameras in adjacent rooms and the dose rate to an operator in the same room is 2 microSv. h-1 for a typical fluorine-18 fluorodeoxyglucose (18F-FDG) study with an initial injected activity of 370 MBq. The scanner has been used for clinical imaging with18F-FDG for neurological and oncological applications. Its novel use for imaging iron-52 transferrin for localising erythropoietic activity demonstrates its sensitivity and resolution advantages over a conventional dual-headed gamma camera. The ECAT ART provides a viable alternative to conventional full ring PET scanners without compromising the performance required for clinical PET imaging.

Safety of long-term high-dose minocycline in the treatment of acne

Minocycline is widely used as a second-line antimicrobial for acne vulgaris. Some patients require doses of up to 200 mg daily to control their acne. To assess the long-term safety of minocycline when used at higher doses, 700 patients treated with minocycline at doses of 100 mg daily, 100/200 mg on alternate days and 200 mg daily, were recruited. The mean duration of treatment was 10.5 months. Side-effects were monitored and full blood count, blood urea, electrolytes and liver function tests were carried out on 200 of the 700 patients. Side-effects were recorded in 13.6%, and included vestibular disturbance, candida infection, gastrointestinal disturbance, cutaneous symptoms (pigmentation, pruritus, photosensitive rash and urticaria) and benign intracranial hypertension. Pigmentation was the only side-effect found to be significantly increased in patients taking higher doses of minocycline, as compared with lower doses (P < 0.01). All patients with pigmentation had taken a total cumulative dose of over 70 g. No significant abnormalities were found in any of the haematological and biochemical profiles. We conclude that minocycline, at doses of up to 200 mg/day, is safe, long-term, for acne, when such doses are clinically necessary.

4-(4-Guanidinobenzoyl)-2-imidazolones and related compounds: phosphodiesterase inhibitors and novel cardiotonics with combined histamine H2 receptor agonist and PDE III inhibitor activity

A series of new positive inotropic agents was synthesized with the aim of combining the pharmacophores of the imidazolone-type phosphodiesterase (PDE) inhibitor enoximone and guanidine-type histamine H2 receptor agonists such as arpromidine. All compounds are para-substituted 4-benzoyl-5-alkyl-2-imidazolones. H2 agonism was incorporated by p-(hetero)arylalkyl substituents, in particular by an imidazolylpropyl guanidine group. In addition analogous ureas, cyanoguanidines, alkyl guanidine carboxylates, and amides were prepared. These functional groups were either directly attached to the phenyl ring or linked by an appropriate spacer. The compounds were screened for positive inotropic activity in the isolated electrically stimulated guinea pig papillary muscle and for inhibition of PDE III (cGMP-inhibited cAMP PDE, isolated from guinea pig heart). The cardiotonics obtained proved to be either PDE III inhibitors, some of them surmounting up to 3-fold the potency of enoximone, or pharmacological hybrids combining both PDE III inhibitor and histamine H2 receptor agonist activities. These hybrids were the most potent positive inotropic substances at the papillary muscle, probably due to their synergistic mechanism of action. The participation of histamine H2 receptors could be demonstrated in the papillary muscle preparation by pretreatment with the H2 antagonist famotidine (10 microM) as well as by further pharmacological experiments using isolated perfused hearts of guinea pigs and rats, isolated guinea pig right atria, adenylyl cyclase and H2 receptor binding assays. At equieffective concentrations the moderate PDE III inhibitor and histamine H2 agonist N1-(4-[(1,3-dihydro-5-methyl-2-oxo-3H-imidazol-4-yl)-carbonyl]phenyl)-N2 - [3-(1H-imidazol-4-yl)propyl]guanidine 65 and the 5-ethyl homologue 66 were about 2 and 10 times more potent than enoximone at the papillary muscle. Moreover, both compounds produced a 2.5-fold higher maximal response than the reference compound.

Functional analysis of mutant neurotrophins deficient in low-affinity binding reveals a role for p75LNGFR in NT-4 signalling

The neurotrophins mediate their effects through binding to two classes of receptors, a tyrosine kinase receptor, member of the Trk family, and the low-affinity neurotrophin receptor, p75LNGFR, of as yet undefined signalling capacity. The need for a two-component receptor system in neurotrophin signalling is still not understood. Using site-directed mutagenesis, we have identified positively charged surfaces in BDNF, NT-3 and NT-4 that mediate binding to p75LNGFR. Arg31 and His33 in NT-3, and Arg34 and Arg36 in NT-4, located in an exposed hairpin loop, were found to be essential for binding to p75LNGFR. In BDNF, however, positively charged residues critical for p75LNGFR binding (Lys95, Lys96 and Arg97) were found in a spatially close but distinct loop region. Models of each neurotrophin were built using the coordinates of NGF. Analysis of their respective electrostatic surface potentials revealed similar clusters of positively charged residues in each neurotrophin but with differences in their precise spatial locations. Disruption of this positively charged interface abolished binding to p75LNGFR but not activation of cognate Trk receptors or biological activity in Trk-expressing fibroblasts. Unexpectedly, loss of low-affinity binding in NT-4, but not in BDNF or NT-3, affected receptor activation and biological activity in neuronal cells co-expressing p75LNGFR and TrkB, suggesting a role for p75LNGFR in regulating biological responsiveness to NT-4. These findings reveal a possible mechanism of ligand discrimination by p75LNGFR and suggest this receptor may selectively modulate the biological actions of specific neurotrophin family members.

Technetium-99m and indium-111 double labelling of granulocytes for kinetic and clinical studies

A new technique of labelling granulocytes with both technetium-99m hexamethylpropylene amine oxime (HMPAO) and indium-111 in a single protocol was developed in order to exploit the advantages of each radiolabel in clinical and investigative studies. Fourteen patients were included in this prospective study. Granulocytes were labelled with both 111In-tropolonate and 99mTc-HMPAO. In vitro shape change assay and in vivo distribution and recovery studies were performed to assess the activation of and damage to these cells due to the labelling procedure. The comparative kinetics of 111In and 99mTc in the blood, liver, spleen, and bone marrow were studied by blood sampling and dual radionuclide imaging early (1 h) and late (24 h) after injection. The functional integrity of the double-labelled granulocytes and the feasibility of the technique were investigated in 14 patients with a painful prosthetic hip due to causes other than infection. The efficiency of double labelling was 63% (SD 14%) for 111In and 39% (SD 12%) for 99mTc-HMPAO. In vitro granulocyte activation and ex vivo recovery values were comparable to those from single radionuclide labelling. No artefactual granulocyte sequestration was seen in the lungs or liver. The radioactivity was distributed between the liver, spleen and bone marrow and, to a lesser extent, the lung. Early 99mTc counts in the liver, spleen and bone marrow, in relation to background, were significantly higher than 111In counts while the reverse was seen in late images.(ABSTRACT TRUNCATED AT 250 WORDS)

Pan-neurotrophin 1: a genetically engineered neurotrophic factor displaying multiple specificities in peripheral neurons in vitro and in vivo

Pan-neurotrophin 1 (PNT-1) is a synthetic trophic factor engineered by combining active domains of the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3) into an NT-3 backbone. This molecule was produced in transiently transfected COS cells or in baculovirus-infected insect cells transfected COS cells or in baculovirus-infected insect cells and subsequently purified to homogeneity. Saturation binding in embryonic spinal sensory neurons demonstrated a greater number of high-affinity binding sites for PNT-1 than for its parental molecule NT-3. PNT-1 was shown to efficiently block the chemical crosslinking of NGF, BDNF, and NT-3 to their cognate Trk receptors and to the low-affintiy NGF receptor expressed on neuronal and nonneuronal cells. PNT-1 stimulated survival and proliferation of MG87 fibroblasts expressing either TrkA, TrkB, or TrkC. PNT-1 also promoted survival of a greater number of embryonic dorsal root ganglion neurons than any of the other neurotrophins alone, and its effects were equivalent to a combination of NGF, BDNF, and NT-3. Analysis of receptor-specific neurotrophic activities demonstrated that PNT-1 efficiently rescued TrkA mRNA-containing sympathetic neurons and TrkB and TrkC mRNA-containing sensory neurons from the dorsal root and nodose ganglia. Finally, PNT-1 showed robust retrograde transport to DRG neurons in vivo after injection into the sciatic nerve. Radiolabeled PNT-1 accumulated in small-, medium-, and large-sized neurons. Coinjection with different unlabeled neurotrophins inhibited PNT-1 transport in distinct subpopulations of neurons of different sizes, suggesting that this molecule affects sensory neurons of different modalities. These results indicate that PNT-1 is a potent and multispecific neurotrophic factor that may be useful in the treatment of peripheral neurophathies and nerve damage.

Prevalence and correlates of depressive syndromes among adults visiting an Indian Health Service primary care clinic

Depression is common among patients visiting primary care clinics. In order to describe the prevalence of depressive syndromes in an American Indian primary care clinic population and to help define the clinical correlates of depressive syndromes in this setting, a clinic-based research study of depression was undertaken by the Indian Health Service (IHS). One hundred and six patients from an IHS primary care clinic were systematically enlisted for participation in the study. Participants completed the Inventory for Diagnosing Depression (IDD). Twenty-two (20.7%) responded with answers scoring positive for a depressive syndrome. Nine of these 22 (8.9% of the 106 participants) met IDD criteria for a major depressive syndrome. A diagnosis of depression, a past history of depression, use of mental health facilities, unexplained pains, and antidepressant medication use were associated with the presence of a depressive syndrome.

Oxygen and 99mTc-MAA shunt estimations in patients with pulmonary arteriovenous malformations: effects of changes in posture and lung volume

BACKGROUND

Patients with arteriovenous malformations are routinely monitored with arterial oxygen saturation (SaO2) estimations (breathing air) from which an oxygen shunt fraction can be calculated. This simple estimation has been compared with an anatomically defined estimate of the right to left shunt using a radioisotopic method. The fall in SaO2 which occurs in patients with pulmonary arteriovenous malformations in the erect posture and at high lung volumes was used to test the ability of SaO2 alone to follow changes in right to left shunt.

METHODS

Radiolabelled albumin macroaggregates (99mTc-MAA) or microspheres (MS) were injected intravenously and kidneys and lungs were imaged. The shunt fraction (QS/QTTc) in the supine position at functional residual capacity (baseline) was obtained by quantifying right kidney radioactivity. On standing or while breath holding at total lung capacity, shunt fraction was calculated from baseline QS/QTTc and from lung counts and the injected dose. Arterial oxygen saturation (SaO2) was recorded by a pulse oximeter for calculation of the oxygen shunt (QS/QTO2) (breathing air).

RESULTS

In the postural study (n = 8) SaO2 decreased from a mean (SD) value of 89 (5)% supine to 80 (6)% erect, corresponding to QS/QTO2 28 (8)% and 44 (8)% respectively. QS/QTTc increased from 28.7 (10.3)% to 39 (14.3)%. In the lung volume study (n = 8) QS/QTTc increased from 16.6 (11.5)% at functional residual capacity to 23.3 (11.9)% at total lung capacity while QS/QTO2 increased from 19.5 (7.5)% to 25.9 (10.6)% respectively. When all measurements were compared for QS/QTTc% and QS/QTO2% (n = 32) the difference in the mean values was 2.5% (absolute) and the limits of agreement between the two methods were +38% to -18% (relative). In neither the postural nor the volume study did delta (QS/QTO2) reliably predict delta (QS/QTTc)%.

CONCLUSIONS

In pulmonary arteriovenous malformations the simple physiological shunt calculated from SaO2 breathing air agreed well with the anatomical right to left shunt measured with 99mTc-MAA, but predicted poorly the changes in anatomical shunt induced by postural or lung volume changes.

Effect of smoking on serum nutrient concentrations in African-American women

The relationship between current cigarette smoking and serum concentrations of vitamins C, E, and A, and of five carotenoids in human serum were examined in 91 low-income, African-American women. General linear models were used to adjust geometric mean serum concentrations of micronutrients for age, dietary and supplement intakes, total energy intake, alcohol intake, medication use, body mass index, and serum concentrations of cholesterol and triglycerides. Among smokers, serum concentrations of alpha-carotene, beta-carotene, cryptoxanthin, and lycopene averaged only 71-79% of the concentrations among nonsmokers. Mean serum concentrations of vitamins C and E and lutein/zeaxanthin were only slightly lower among smokers relative to nonsmokers, and current smokers had higher serum concentrations of vitamin A. Among current smokers, mean serum concentrations of all five carotenoids decreased with an increase in the amount smoked. The negative effect of smoking on serum concentrations of antioxidant carotenoids may pose a serious health risk in low-income populations already at higher risk for many chronic diseases.

Changes in intra- or extracellular pH do not mediate P-glycoprotein-dependent multidrug resistance

P-glycoprotein (Pgp)-mediated multidrug resistance (MDR) is thought to result from active extrusion of lipid-soluble, titratable chemotherapeutic agents. Given the lack of demonstration of coupling between ATP hydrolysis and drug transport, the resistance to chemically unrelated compounds, and findings of elevated intracellular pH (pHi), it has been proposed that reduced intracellular accumulation of drugs in MDR is due to changes in the pH difference across the plasma membrane. Elevation of pHi or decrease in local extracellular pH (pHo) could reduce the intracellular accumulation of the protonated chemotherapeutic drugs and account for Pgp-mediated MDR. Alternatively, changes in pHi or pHo could increase drug efflux by other mechanisms, such as coupled transport involving H+ or OH-, or allosteric effects on Pgp or other proteins. Both mechanisms could operate independently of the charge of the substrate. The possibility of a role of pHi in drug efflux is important to test because of the clinical significance of the phenomenon of MDR of tumors. We tested this hypothesis and found that MDR can occur in cells with low, normal, or high pHi. Further, resistant cells exhibited reduced steady-state drug accumulation and increased efflux without changes in local pHo. Finally, acute changes in pHi had no appreciable effect on Pgp-mediated drug efflux. We conclude that Pgp-mediated MDR is not a consequence of changes in pHi or pHo.

Growth hormone stimulates cortical bone formation in immature hypophysectomized rats

Daily subcutaneous injections of rat derived growth hormone to immature, hypophysectomized rats stimulated significant increases in body weight gain, serum osteocalcin, skeletal alkaline phosphatase and incorporation of radioactive thymidine and proline into the compact bone of femurs and tibiae. Equimolar doses of insulin-like growth factor-II did not produce similar biological effects. The data support the contention that growth hormone at equimolar concentration is a stronger osteogenic agent than is insulin-like growth factor-II in vivo.

Evidence for extrathymic changes in the T cell receptor gamma/delta repertoire

The germline repertoire of variable genes for the TCR-gamma/delta is limited. This, together with the availability of several V delta-specific and a C delta-specific mAbs, has made it possible to assess differences in the TCR-gamma/delta repertoire in man. TCR-gamma/delta cells expressing particular V gene segments have been previously shown to be localized in different anatomical sites. In this study, analysis of TCR-gamma/delta V gene segment usage performed on subjects from the time of birth through adulthood revealed striking age-related changes in the TCR-gamma/delta repertoire in peripheral blood. V delta 1+ gamma/delta T cells predominated in thymus as well as in peripheral blood at birth and then persisted as a relatively constant proportion of CD3+ PBL. However, V delta 2+ gamma/delta T cells that constitute a small proportion of the CD3+ cells in thymus and in peripheral blood at birth, then expand and account for the major population of gamma/delta T cells in PBL in adults. No parallel postnatal expansion of V delta 2+ cells in the thymus was observed, even when paired thymus-peripheral blood specimens were obtained on subjects between the ages of 3 d and 8 yr. The subset of V delta 2+ lymphocytes that was expanded in peripheral blood expressed high levels of CD45RO suggesting prior activation of these cells, consistent with the possibility that their expansion might have resulted from exposure to foreign antigens or superantigens. In contrast, V delta 1+ T cells in PBL showed no comparable increase in relative numbers and were either negative or expressed only low levels of CD45RO. Consistent with evidence for extrathymic peripheral expansion of selective TCR-gamma/delta subsets, no link between MHC haplotype and differences in the TCR-gamma/delta V gene usage between individuals was apparent, and identical twins displayed TCR-gamma/delta variable gene segment phenotypes that were strikingly different from one another. The elements that determine the TCR-gamma/delta repertoire in individuals are not known. It is possible that both thymic selection and extrathymic factors may influence the peripheral repertoire. Recently, TCR-gamma/delta+ lymphocytes have been shown to expand markedly in peripheral lymphoid tissues and infectious lesions in response to mycobacterial antigens, and a correlation between mycobacterial responses and TCR-gamma/delta V gene usage has been shown in mice. The data presented here demonstrated peripheral age-related changes in the gamma/delta repertoire and point to the importance of extrathymic expansion of specific gamma/delta subsets in generating the human TCR-gamma/delta repertoire.

Building sickness, are symptoms related to the office lighting?

Office lighting has been suggested as one of the possible factors in producing 'building sickness'. Health questionnaires were completed by 106 out of 109 (97%) workers in six randomly sampled multi-occupied offices in each of two buildings, one air-conditioned and one naturally ventilated. There was a significantly higher prevalence of work-related headache and work-related lethargy in the air-conditioned building than in the naturally ventilated one. There was also less daylight in the air-conditioned building and lower mean luminance and illuminance of the work positions despite there being more lights on (p less than 0.01). The workers had a greater dislike of fluorescent lighting (p less than 0.01) and overall found the lighting to be less comfortable (p less than 0.01) and glare readings were higher. The workers perceived their control of lighting as poorer (p less than 0.001) and consequently there was less agreement about it (p less than 0.001). Those with work-related headache found the lighting less comfortable (p = 0.059) and perceived more glare (p less than 0.05). This study suggests the need to maximize the use of natural light from untinted windows, to reduce the impingement of fluorescent tubes on the line of sight and to return the control of levels of lighting to each individual worker.

Very late activation antigens on rheumatoid synovial fluid T lymphocytes. Association with stages of T cell activation

Lymphocytes from the synovial fluid of eight out of eight rheumatoid arthritis (RA) patients had elevated very late activation antigen-1 (VLA-1) expression (10-36% positive cells), whereas peripheral blood lymphocytes (PBL) from RA patients and healthy controls had low VLA-1 expression (0-6% positive cells). During 1-2 wk of in vitro culture, VLA-1 increased on synovial fluid cells but remained low on PBL. In comparison, the interleukin 2 receptor (IL-2 R) was less prominent than VLA-1 on fresh synovial fluid cells, did not increase on cultured synovial fluid T cells, but did increase greatly on cultured PBL. The mitogen PHA reversed or prevented the appearance of VLA-1+, IL-2 R- synovial fluid cells during in vitro culture, thus giving IL-2 R+, VLA-1- cells. These results emphasize that VLA-1+ SF cells are different from resting cells or IL-2 R+ activated PBL T cells, and VLA-1 on synovial fluid T cells may be incompatible with mitogen stimulation. In addition, the VLA-2 heterodimer (165,000/130,000 relative molecular mass [Mr]) was regulated opposite to the VLA-1 heterodimer (130,000/210,000 Mr) on synovial lymphocytes, and thus the VLA-1/VLA-2 ratio is another indicator of the stage of T cell activation.

Extended haplotypes of chromosome 6 in adult rheumatoid arthritis

In 46 patients with rheumatoid arthritis (RA) the allele C4B*3 occurred in 6 patients, while among 350 normal controls, it occurred 6 times (P less than 0.00002). Among 9 white and 1 black families, each of which had 2 or more members with RA, there were 36 haplotypes associated with RA. An extended haplotype (specific HLA-B, DR, complotype haplotypes in significant linkage disequilibrium) containing C4B*3: HLA-B15, DR4, BF*S, C2*C, C4A*3, C4B*3, was found twice (P less than 0.001) among whites with the disease-associated chromosomes.