Possible antimigraine mechanisms of action of the 5HT1F receptor agonist LY334370

This study investigated whether the selective 5HT1F receptor agonist LY334370 has other possible antimigraine mechanisms in addition to the proposed inhibition of dural plasma extravasation. LY334370 (up to 10(-5) M) had no vasoconstrictor effects on human cerebral arteries in vitro. It had no effect (up to 10 mg kg-1, i.v.) on neurogenic vasodilation of dural blood vessels produced by electrical stimulation of the dura mater in anesthetized rats. Nor had it any effect (at 3 mg kg-1, i.v.) on the hyperalgesia produced by injection of carrageenan into the paw of conscious rats or on nociceptive reflex responses in the spinalized, decerebrate rabbit (up to 3 mg kg-1, i.v.), indicating that it has no general analgesic properties. However, it significantly inhibited activation of second-order neurons in the trigeminal nucleus caudalis produced by electrical stimulation of the dura mater in anesthetised rats at 3 mg kg-1, i.v. These results provide evidence to suggest that LY334370 has a central mechanism of action in blocking the transmission of nociceptive impulses within the trigeminal nucleus caudalis and that this may represent a mechanism through which it has its antimigraine effect.

Psychobiological markers of stress in pregnancy: 6-sulfatoxymelatonin--a longitudinal study

Maternal stress, physical and psychological, has been associated with adverse pregnancy outcome. The pineal gland is a physiological transducer that reflects adrenergic input. In a recent pilot study, we found urinary 6-sulfatoxymelatonin, the melatonin metabolite, to be elevated after a women spent a day at work compared to levels after a day off work, a leisure day. To evaluate the value of melatonin as a marker of stress, we evaluate melatonin metabolite levels in 121 women, along with perceived anxiety levels and urinary cortisol. Urinary cortisol and maternal anxiety levels each were significantly higher after a work day compared to a leisure day p = .03 and p = .001, respectively. 6-Sulfatoxymelatonin was not significantly different between work and leisure. Changes in cortisol levels were correlated with changes in melatonin metabolite levels (r = .62, p = .001). There was no correlation between changes in anxiety between work and leisure and changes in 6-sulfastoxymelatonin. We found no correlation with 28 week 6-sulfatoxymelatonin or 28-week cortisol and birth weight or gestational age at delivery. Results of this study suggest that melatonin secretion may not be a valuable marker for stress in pregnancy.

Non-invasive RNA-based determination of fetal Rhesus D type: a prospective study based on 96 pregnancies

OBJECTIVES

To develop a non-invasive method for determining fetal RhD status in order to provide improved care for women most at risk.

DESIGN

A prospective study.

METHODS

Fetal erythroblasts were enriched from the peripheral circulation of 96 RhD negative women with pregnancies at various stages in gestation using discontinuous density gradients. Amplification of RhD-specific mRNAs was carried out by reverse transcription-polymerase chain reaction assay. RNA, rather than DNA, was selected for amplification because it rarely contaminates samples, thus resulting in fewer false positives; moreover, its presence in multiple copies per cell should enhance the sensitivity of the assay, resulting in fewer false negatives. The study was prospective, relying on postnatal serological confirmation of RhD phenotype.

RESULTS

The assay was 75% accurate at predicting fetal RhD status, comparing favourably with standard genomic DNA-based assays. However, we found that accuracy dropped from 85% (29/34) in the third trimester of pregnancy, to 82% (32/39) in the second and 48% (11/23) in the first trimester. Discordant data were due to false negatives in the majority (78%) of cases.

CONCLUSIONS

We suggest that reverse transcription may be a useful and perhaps more sensitive alternative to standard genomic polymerase chain reaction in the majority of cases. However, under certain circumstances the absence or reduction of fetal erythroblasts or possibly RhD mRNA in some preparations may compromise the accuracy of the assay.

Selective NMDA NR2B antagonists induce antinociception without motor dysfunction: correlation with restricted localisation of NR2B subunit in dorsal horn

The present study investigated the regional distribution of the N-methyl-D-aspartate (NMDA) receptor containing the NR2B subunit protein in rat lumbar spinal cord and examined whether selective NR2B antagonists would exhibit antinociception with reduced side-effect liability than subtype non-selective NMDA antagonists and anticonvulsants. Immunocytochemical studies showed the NR2B subunit had a restricted distribution, with moderate labelling of fibres in laminas I and II of the dorsal horn suggesting a presynaptic location on primary afferent fibers and possible involvement in pain transmission. In the in vivo studies, the NMDA/glycine antagonists (MK-801, 0.02-1 mg/kg i.p., L-687,414 10-300 mg/kg i.p., and L-701,324 1-10 mg/kg i.p.) and the anticonvulsant, gabapentin (10-500 mg/kg p.o.), induced rotarod deficits at antinociceptive doses. In contrast, the selective NR2B antagonists, (+/-)-CP-101,606 (1-100 mg/kg p.o.) and (+/-)-Ro 25-6981 (3-100 mg/kg i.p.) showed a significant dose window. (+/-)-CP-101,606 caused no motor impairment or stimulation in rats at doses up to 100 mg/kg p.o., which is far in excess of those inhibiting allodynia in neuropathic rats (ID50 4.1 mg/kg, p.o.). (+/-)-Ro 25-6981 also showed a significant separation (ID50 allodynia 3.8 mg/kg, i.p.), however, some disruption of rotarod performance was observed at 100 mg/kg. The anticonvulsant lamotrigine (3-500 mg/kg p.o.) also showed a good dose window. These findings demonstrate that NR2B antagonists may have clinical utility for the treatment of neuropathic and other pain conditions in man with a reduced side-effect profile than existing NMDA antagonists.

Analysis of the neurotrophic effects of GPI-1046 on neuron survival and regeneration in culture and in vivo

The putative neurotrophic effects of the immunophilin ligand GPI-1046 were evaluated in established experimental systems of neuron survival and axon growth in vitro and in vivo. GPI-1046 marginally increased neurite outgrowth of chick dorsal root ganglia in culture under conditions where a very robust effect of nerve growth factor was seen. GPI-1046 failed to protect dopaminergic neurons from 1-methyl-4-phenylpyridinium in culture or to protect cultured cortical neurons from experimentally induced apoptosis in vitro. In adult rats in vivo, daily administration of GPI-1046 (10 mg/kg, s.c.) for three days enhanced the maximal regeneration distance of both motor and large myelinated sensory axons measured using an electrophysiological assay. However, detailed morphometric analysis of these animals failed to provide evidence for an increase in axon numbers in GPI-1046-treated animals. The ability of GPI-1046 to promote the recovery of dopaminergic function following unilateral 6-hydroxydopamine lesions of the substantia nigra was also tested in rats. In the first study, the duration of amphetamine (3 mg/kg, s.c.)-induced circling, but not the maximal number of rotations, was significantly reduced in animals treated with GPI-1046 for five days (10 mg/kg/day). In a second study, testing the effects of delayed GPI-1046 administration, chronic treatment with GPI-1046 (10 mg/kg/day) for two weeks, beginning one month after surgery, did not alter circling responses. Morphometric analysis failed to reveal any changes in either the density of tyrosine hyroxylase-positive fibres in dopaminergic target areas or in cell numbers in the substantia nigra in both experiments. Thus, while GPI-1046 produced marginal effects on neurite outgrowth in dorsal root ganglia cultures and on functional paramaters of nerve regeneration in vivo, we failed to obtain evidence in support of the notion of a general neuroprotective effect of the compound or for an effect on morphologic nerve regeneration in vivo.

A combination chemotherapy protocol (VELCAP-L) for dogs with lymphoma

Ninety-eight dogs with lymphoma treated with a 5-drug combination chemotherapy regimen (vincristine, L-asparaginase, cyclophosphamide, doxorubicin, prednisone [VELCAP-L]) were evaluated for pretreatment characteristics predictive for response and remission duration. The complete remission rate was 69%, with a median remission duration of 55 weeks. Dogs with advanced stage of disease, constitutional signs, dogs that were older, and dogs that were dyspneic were less likely to achieve remission. Once in remission, small dogs and dogs without pretreatment thrombocytopenia were likely to have longer remission duration. Toxicoses were frequent, but rarely fatal, and no predictitive factors were found for a dog developing toxicoses. VELCAP-L is an effective treatment for dogs in stage I-III lymphoma, particularly in young, small animals.

Determination of the aversion of farmed mink (Mustela vison) to carbon dioxide

High concentrations of carbon dioxide are commonly used to kill mink before their pelts are removed. The aversiveness of this procedure was investigated by using a passive avoidance technique. Eight mink were trained to obtain a reward (a novel object) by entering a chamber which could be filled with carbon dioxide, as under commercial conditions (over 80 per cent by volume). In the absence of carbon dioxide, mink entered the chamber within a mean (sd) of 16 (2.1) seconds and spent 45 (12) per cent of the next 10 minutes interacting with the novel object. When there was carbon dioxide in the test chamber, the mink would not enter it and coughed and recoiled from the chamber's entrance instead. It was concluded that the mink detected and avoided high concentrations of carbon dioxide, and that if mink are to be killed humanely, less aversive techniques should be used.

Effectiveness of one-year participation in school-based volunteer-facilitated peer support groups

This study evaluated the effectiveness of one-year participation in a program of volunteer-facilitated peer support groups conducted in a southeast Texas high school. One hundred eighteen students who experienced emotional distress or behavioral problems voluntarily participated in weekly groups facilitated by adult volunteers who were not mental health professionals. Seventy-six participants anonymously assessed the program using an instrument developed to evaluate the group experience. Results indicated that the program was highly accepted by the students even though two-thirds had initially felt uncomfortable in the groups. There was significant improvement in the interpersonal, internal, and school domains. Two-thirds of the alcohol and substance users reported reducing their intake or abstaining. The beneficial effects reported by a majority of the participants indicate that schools opting to implement this early intervention program can look forward to encouraging results within one year.

Assessing animal priorities: future directions

Copyright 1998 The Association for the Study of Animal Behaviour..

A demanding task: using economic techniques to assess animal priorities

Copyright 1998 The Association for the Study of Animal Behaviour.

A high incidence of melanoma found in patients with multiple dysplastic naevi by photographic surveillance

OBJECTIVES

(1) To assess the incidence of melanoma in a cohort of patients with dysplastic melanocytic naevi (DMN) and the relationships between incident melanomas and preexisting naevi and between melanoma risk and numbers of DMN. (2) To examine the role of the patient versus the physician in detecting melanoma and the relative value of surveillance versus prophylactic excision.

DESIGN

Prospective cohort study.

PATIENTS AND SETTING

Two hundred and seventy-eight adults, each with five or more DMN, were followed up for a mean period of 42 months in a private dermatology practice. DMN were clinically diagnosed.

RESULTS

Twenty new melanomas were detected in 16 patients, corresponding to an age-adjusted incidence of 1835/100000 person-years, 46 times the incidence in the general population. Eleven were detected because of changes evident in comparison with baseline photographs and nine were detected by patients or their partners. Thirteen of the 20 melanomas arose as new lesions and only three from DMN. Melanoma risk rose with increasing numbers of DMN.

CONCLUSIONS

Increasing numbers of DMN are associated with increasing melanoma risk. Surveillance (baseline photography and follow-up) enabled early diagnosis of melanoma and was very much more cost-effective in preventing life-threatening melanoma than prophylactic excision of DMN.

Counselling implications of chromosomal abnormalities other than trisomy 21 detected through a maternal serum screening programme

OBJECTIVE

To identify counselling requirements, we reviewed the frequency and type of non-trisomy 21 chromosome abnormalities found at amniocentesis after maternal serum screening for Down's syndrome.

DESIGN

The study involved a review of the cytogenetic results of amniocenteses performed because of a raised maternal serum screening risk.

SETTING

The maternal serum screening and amniocenteses were performed at hospitals in the Yorkshire region.

SAMPLE

1715 amniocenteses were performed as a result of a raised maternal serum screening risk for the period 1990 to 1993.

METHODS

The cytogenetic results were classified into the main categories of numerical and structural chromosomal abnormalities.

MAIN OUTCOME MEASURES

The nature and frequency of abnormal cytogenetic results were identified in which parental samples were required in order to determine if the abnormal finding was de novo or familial and/or for which specialist genetic counselling was required.

RESULTS

Sixty-nine pregnancies of 1715 amniocenteses were identified with a chromosomal abnormality (4.0%): 35 (2.0%) with trisomy 21 and 34 (2.0%) with another chromosomal abnormality. For 20 of these 34 abnormalities, parental karyotypes were required and in 29 of the 34 specialist genetic counselling was required.

CONCLUSIONS

Women undergoing maternal serum screening and, in particular, those proceeding to amniocentesis, should be informed that there is an equal chance that a chromosomal abnormality other than trisomy 21 will be found at amniocentesis, the nature of which usually requires parental samples and specialist counselling.

Imaging inflammatory diseases with neutrophil-specific technetium-99m-labeled monoclonal antibody anti-SSEA-1

Imaging inflammatory diseases with a 99mTc-labeled neutrophil-specific agent that can be injected directly intravenously continues to be a challenge.

METHODS

The antibody, anti-SSEA-1, chosen from studies of 10 neutrophil-specific MAbs, recognizes CD-15 antigens (5.1 x 10(5)/human PMN) with a high association constant (kd = 10(-11) M). One hundred micrograms of MAb labeled with 10-20 mCi 99mTc either by a direct or DTPA conjugation method were injected intravenously into 12 patients (9 men, 3 women, aged 19-48 yr) with clinical evidence of ongoing inflammatory processes. Vital signs of all patients were recorded before and up to 3 hr following administration of the MAb. HAMA was determined in two patients. Anterior and posterior spot views and whole-body images were obtained. All patients except one underwent biopsy, US or CT examinations and/or surgical procedures. Blood samples collected from five patients were analyzed. In nine patients, quantitative organ distribution was determined and radiation dosimetry was calculated.

RESULTS

Labeling yields were 94.8% +/- 1.4% and 95.8% +/- 3.5%, respectively. All patients had unequivocally positive images within 3 hr of the MAb injection. Eleven of these were confirmed by other modalities. One patient recovered on antibiotics and was sent home without surgery or other procedures. The lack of radioactivity in the thyroid or gastrointestinal tract indicated that the in vivo stability of the agent was excellent. At 3 hr postinjection, bladder activity in six patients was 1.3% +/- 0.4% of the administered dose. At this time, splenic uptake (7.7% +/- 1.0% ad. dose) and red marrow uptake (14 +/- 1.8%) were lower than those of 111In-WBC. At 49.0% +/- 3.2% administrated dose, liver uptake was at the upper limit with 111In-WBC uptake. Renal uptake was only 2.4% +/- 0.03% administered dose. At 2 hr postinjection, 14% to 51% of the radioactivity was associated with PMN. Radioactivity with lymphocytes was 0.7% to 10.9%, 1.2% to 4.3% with platelets and 1.1% to 2.4% with RBC. No HAMA were detectable in either patient, and no adverse reaction was detectable in any patient.

CONCLUSION

Results are highly encouaging and have prompted us to prepare a kit for instant preparation and to initiate clinical trials.

Altered thrombomodulin staining in blistering dermatoses

The immunocytochemical distribution of thrombomodulin (TM) was examined in sections of skin from patients with blistering dermatoses occurring in the presence and absence of acantholysis. Skin sections were stained using polyclonal and monoclonal anti-human TM antibodies and were correlated with the staining pattern that resulted when using the monoclonal antibody 32-2B, which recognises the chief desmosomal adhesion molecule desmoglein I (DG I). Our study demonstrates a loss of TM staining in acantholytic dermatoses, occurring only in the region of actual disruption of the intercellular bridging between keratinocytes in the stratum spinosum. The thrombomodulin antigen expression paralleled the DG I expression. The strong correlation between the DG I and TM immunostaining pattern in both normal skin and acantholytic dermatoses supports the concept that TM has a role in mediating adhesion processes between keratinocytes.

Differentiation of growth retarded from normally grown fetuses and prediction of intrauterine growth retardation using Doppler ultrasound

OBJECTIVE

To assess the hypothesis that infants exhibiting catch-up growth as an indicator of intrauterine growth retardation (IUGR) have a higher incidence of predelivery abnormal Doppler results. SETTING. Obstetric unit, St James's University Hospital, Leeds.

PARTICIPANTS

One hundred and ninety-six women with singleton pregnancies at high risk of IUGR, delivered between October 1992 and August 1993.

MAIN OUTCOME MEASURES

Postnatal catch-up growth during the first seven months.

RESULTS

Forty-six of the 196 infants demonstrated catch-up growth and were therefore classified as growth retarded; 85% of this group had had abnormal Doppler results prior to delivery, compared with 14% of the normally grown group. However, there is considerable overlap in birthweight ratio distribution between the two groups.

CONCLUSION

This study confirms the existence of a population of IUGR infants of average birthweight ratio. Doppler appears to distinguish IUGR (as defined by catch-up growth) from normal growth more successfully in infants with an average birthweight ratio than in infants with a low birthweight ratio and is a better predictor of IUGR than SGA.