Biomedical subjects
Publications and source records attributed to P Martin.
The tuberculin skin test, if carefully standardised, is a useful diagnostic and screening tool. Whilst it is easier to apply in unvaccinated populations, with care, available data may be used to help interpret the tests in populations such as New Zealand where vaccination has been widespread.
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The brindled mottled mouse has a mutation on the X-chromosome which causes alterations in copper metabolism. One role for copper is as a cofactor for dopamine-beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine (NE). This may explain the fact that the hemizygous males have low concentrations of NE, as well as high concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in the brainstem and forebrain. The present study quantified serotonin (5-HT) immunoreactive fibers in the cerebral cortex and striatum of hemizygous males and control littermates on postnatal (P) days 7, 10, 12 and 14. The density of 5-HT immunoreactive fibers was measured using a digitized imaging system in conjunction with darkfield microscopy. Measurements of 5-HT innervation showed an age-dependent increase in density of 5-HT immunoreactive fibers in all layers of the cerebral cortex, with fiber density in brindled mice approximately 70% greater than controls by P14. High performance liquid chromatography confirmed the increased concentrations of 5-HT and 5-HIAA, and the low concentration of NE, in several regions. We believe that these results are an example of heterotypic sprouting of 5-HT neurons, similar to that observed in neonatal rats given 6-hydroxydopamine (6-OHDA). If so, these data provide the first description of 5-HT heterotypic sprouting in mice, and the first description of 5-HT heterotypic sprouting resulting from a natural disease state, rather than an experimentally induced lesion.
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Maternal-effect sterile (mes) genes encode maternal components that are required for establishment and development of the germline. Five such genes have been identified in the nematode Caenorhabditis elegans. Mutations in one of the genes result in defects in the asymmetric division and cytoplasmic partitioning that generate the primordial germ cell P4 at the 16-24-cell stage of embryogenesis. As a result of these defects, the P4 cell is transformed into a muscle progenitor and mutant embryos develop into sterile adults with extra body muscles. Mutations in the other four mes genes do not affect formation of the germline during embryogenesis, but result in drastically reduced proliferation of the germline during post-embryonic stages and in an absence of gametes in adults. The failure to form gametes may reflect a defect in germline specification or may be a consequence of reduced germline proliferation. We are currently testing these two possibilities. In addition to the mes gene products, wild-type function of the zygotic gene glp-4 is required for normal post-embryonic proliferation of the germline. Germ cells in glp-4 mutant worms are arrested in prophase of the mitotic cell cycle and are unable to enter meiosis and form gametes. Thus, following establishment of the germ lineage in the early embryo, both maternal and zygotic gene products work in concert to promote the extensive proliferation of the germline and to enable germ cells to generate functional gametes.
The prevalence of anti-HCV was determined in 1,309 leprosy patients and a control group of 1,469 subjects from 6 sub-Saharan African countries and the Yemen. Sera found positive by an initial second generation ELISA were subjected to 3 additional confirmatory tests. The anti-HCV prevalence in leprosy patients (7.1%) was significantly higher than in the control group (2.6%). HCV seroprevalence increased with age in both the control and leprosy groups. No statistically significant difference could be found between anti-HCV prevalence and the several clinical forms of leprosy among patients. The results of this study indicate a high degree of exposure or chronic carriage of hepatitis C among leprosy patients.
Cultured peripheral blood lymphocytes (PBL) from HTLV-I-infected individuals proliferate in the absence of added mitogens and/or cytokines. In an attempt to answer questions regarding the activating signals for cells and virus, antibodies that react with cell surface components that are known to regulate cell activation and antibodies reacting with viral proteins were added to cultures of PBL from HTLV-I-infected, disease-free individuals. Spontaneous proliferation and virus production increased in the presence of antibodies reacting with CD3 and alpha/beta T cell receptors (TCR) while antibodies to HLA class II and viral proteins had no effect. Addition of HLA class I antibodies shut down virus production and cell proliferation. These observations indicate that both virus and cell activation may occur through the alpha/beta TCR on the infected cell. Cyclosporin A, however, markedly decreased cell proliferation but had only a modest suppressive effect on virus production. Thus, the uncoupling of cell proliferation from virus production by cyclosporin A suggests the possibility that the signal transduction pathways for these two events are different.
Cattle microsatellite clones (136) were isolated from cosmid (10) and plasmid (126) libraries and sequenced. The dinucleotide repeats were studied in each of these sequences and compared with dinucleotide repeats found in other vertebrate species where information was available. The distribution in cattle was similar to that described for other mammals, such as rat, mouse, pig, or human. A major difference resides in the number of sequences present in the bovine genome, which seemed at best one-third as large as in other species. Oligonucleotide primers (117 pairs) were synthesized, and a PCR product of expected size was obtained for 88 microsatellite sequences (75%). Synteny or chromosome assignment was searched for each locus with PCR amplification on a panel of 36 hamster/bovine somatic cell hybrids. Of our bovine microsatellites, eighty-six could be assigned to synteny groups of chromosomes. In addition, 10 other microsatellites--HEL 5, 6, 9, 11, 12, 13 (Kaukinen and Varvio 1993), HEL 4, 7, 14, 15--as well as the microsatellite found in the kappa-casein gene (Fries et al. 1990) were mapped on the hybrids. Microsatellite polymorphism was checked on at least 30 unrelated animals of different breeds. Almost all the autosomal and X Chr microsatellites displayed polymorphism, with the number of alleles varying between two and 44. We assume that these microsatellites could be very helpful in the construction of a primary public linkage map of the bovine genome, with an aim of finding markers for Economic Trait Loci (ETL) in cattle.
The present study was aimed at clarifying to what extent the hypermotility induced by the uncompetitive N-methyl-D-aspartate (NMDA) antagonist MK-801 depends on dopamine (DA) D-1 compared to D-2 receptor tone. The D-1 receptor antagonist SCH 23390 was found to reduce locomotion to a greater extent in MK-801-treated than in vehicle-treated mice, whereas the reverse appeared to be the case for the DA D-2 receptor antagonist raclopride. In other words, MK-801-induced hyperactivity was more readily antagonized by SCH 23390 than by raclopride and, thus, DA D-1 receptors seem to be more important than D-2 receptors for MK-801-induced hyperactivity. These results are in line with our previous observation that MK-801 generally interacts synergistically with a DA D-1 but not with a D-2 receptor agonist in monoamine-depleted mice. In view of the possible role of deficient glutamatergic neurotransmission in schizophrenia, our findings underline the importance of investigating the efficacy of selective DA D-1 antagonists in this disorder.
The present study compared the performance on apraxia tests and additional motor tasks between medicated chronic schizophrenic inpatients (n = 21) and healthy subjects (n = 21). Praxis testing did not reveal a clear-cut apractic syndrome in the patient group. The most striking difference between patients and healthy controls was the more frequent use of body parts as object (BPO) by schizophrenic patients (P < 0.0003). There was no significant difference in psychopathology between subgroups classified according to their BPO performance, although a tendency towards a difference in duration of illness and the actual hospitalization period existed between BPO subgroups. Schizophrenic patients performed more poorly than controls in frontal motor tasks: sequencing, including oral sequential movements, and reciprocal innervation. Frontal motor task performance tended to be related to the negative dimension of schizophrenia in accordance with previous studies. The data do not support the assumption that BPO performance is part of a multidimensional concrete attitude in schizophrenic patients. Nevertheless, this peculiarity in motor behaviour might be a link between neurophysiology and psychopathological phenomenology in schizophrenia. We therefore suggest further investigation focusing the performance of object-related pantomime movements in schizophrenic patients.
The aim of this study was to assess the relative impact of co-mobidity and of symptom severity on the costs of caring for patients with generalized anxiety disorders (GAD). One thousand and forty-two patients with GAD according to DSM III-R were observed by psychiatrists using a cross-sectional methodology. Demographic, clinical, therapeutic as well as health care utilization data were collected at a single point in time. Patients were stratified according to prevalence of co-morbidity. An economic analysis was performed based on a societal perspective. Hospitalizations and losses of productivity were the two major components of costs both in patients with and without co-morbidity. On the other hand costs of pharmaceuticals remain a marginal component of costs associated with GAD in the two groups. Controlling for confounding variables, the prevalence of health care utilisation was found to be significantly higher in patients with co-morbidity for hospitalization, laboratory tests, medications and absenteeism from work. Most of cost components were found to be significantly higher in patients with co-morbidity. The relative risk of health care utilization was higher in patients with co-morbidity, past history of anxiety, high level of anxiety as well as in older patients. Overall our findings suggest that both co-morbidity and symptom severity play a role in cost generation in GAD patients.
OBJECTIVES: In order to use cryopreserved teeth in laboratory studies, cryopreservation must not modify the functional properties of teeth, in particular dentin permeability. The purpose of this study was to evaluate the effects of tooth cryopreservation on human dentin permeability. METHODS: Three hundred and sixty freshly extracted human noncarious third molars were used. The teeth were randomly assigned to two groups: 180 teeth were stored in phosphate-buffered saline at 4 degrees C and tested within 4 h of collection; 180 teeth were cryopreserved. Hydraulic conductance was calculated according to the method developed by Pashley (Outhwaite et al., 1976). RESULTS: Cryopreserved teeth presented a hydraulic conductance of 8.97 x 10(-3) +/- 4.21 x 10(-3) microL.cm-2.min-1.cm.H(2)0(-1) slightly higher than the hydraulic conductance of the freshly extracted teeth of 8.03 x 10(-3) +/- 3.87 x 10(-3) microL.cm-2.min-1.cm.H(2)0(-1). No statistically significant difference was found between the two groups. SIGNIFICANCE: Under the conditions of this study, cryopreservation did not modify dentin permeability.
The lung is the primary focus of complications associated with adult respiratory distress syndrome (ARDS) and increased activation of granulocytes has been implicated in the genesis of ARDS. In the present study, plasma granulocyte elastase levels were measured in 24 patients undergoing lung resection for non-small cell lung carcinoma. Pre-, peri- and post-operative assessments of plasma elastase levels were made of patients who underwent a partial resection (lobectomy, n = 13) and patients who underwent a complete lung resection (pneumonectomy, n = 11). Preoperatively, values were similar for both patient cohorts and did not differ from those of normal volunteers. However, immediately (1 h) post-operation, elastase levels in patients who had undergone pneumonectomy were significantly elevated (300% of baseline value, P < 0.005), whereas levels were unchanged in lobectomy patients. On the 1st post-operative day (POD), elastase levels had returned to normal in pneumonectomy patients, whilst lobectomy patients now exhibited increased plasma elastase levels which remained marginally increased until the time of discharge (P < 0.05). The determinants of granulocyte activation following lung resection remain to be elucidated but may potentially relate to ischemic reperfusion in patients undergoing lobectomy, or alternatively may simply reflect the extent of manipulation, compression and contusion of lung tissue.
Fifteen patients (9 male, 6 female) undergoing peripheral vascular surgery were monitored during surgery for evidence of subclinical anticoagulation using the activated coagulation time (ACT), thromboelastography (TEG), and heparin titration monitoring. Assessments were made at 30-minute intervals before and after the occlusion clamp. Mean (+/- SD) ACT values preoperatively were 111 (17) seconds, and 10 minutes after 5,000 IU of heparin, the ACT was 264 (57) seconds (P < 0.001). Intraoperatively, there was a significant decline in ACT values at 30 minutes (ACT 228 [50] sec, P < 0.005) and 60 minutes (200 [46] sec, P < 0.001) postheparin. No significant difference in ACT was observed between samples drawn distally and proximally to the clamp. TEG profiles were abolished in all patients immediately following heparinization. However, in 2 patients nearly complete return of the TEG coagulation profile was observed prior to the termination of the procedure and was associated with ACT values less than 160 seconds. The heparin device was unable to accurately monitor heparin elimination at these low doses. Variability of patient response to heparinization necessitates the use of intraoperative monitoring of anticoagulation during peripheral vascular surgery.
Wound healing in the embryo, just as in the adult, comprises two tissue movements: re-epithelialisation and connective-tissue contraction. In this brief review we describe our recent studies of these two movements in both chick and rodent embryo model systems. In the chick we have evidence that the embryonic wound epidermis is drawn forwards by contraction of an actin pursestring extending around the circumference of the wound, rather than by lamellipodial crawling as in adult healing. Significant connective-tissue contraction also occurs. In the rat and mouse embryo we have examined expression of transcription factors and growth factors at the wound edge. We discuss our observations that the immediate-early gene c-fos and the growth factor transforming growth factor beta-1 are rapidly induced at the embryonic wound margin, and the possibility that these signals may trigger proliferation of wound edge cells and contraction of the exposed wound mesenchyme.
A method is described for the collection and quantitation of formaldehyde, acetaldehyde, and acetone in sidestream cigarette smoke. Using the "fishtail" chimney procedure (1), sidestream smoke is drawn by vacuum through the chimney, a Cambridge filter pad (Performance Systematics Inc.; Caledonia, MI), and into an impinger containing a solution of 2,4-dinitrophenylhydrazine (DNPH), whose solubility in acetonitrile was increased by using diglyme as a constituent of the collection derivatization solution. The chimney is rinsed with DNPH solution to remove "formaldehyde", and the rinse is added to the impinger solution. This combined wash and impinger solution is used to extract the Cambridge pad. An aliquot of the extract is analyzed by high-performance liquid chromatography using a reversed-phase column, ultraviolet detection, and a mobile phase gradient with tetrahydrofuran as a modifier. Acrolein is detected but gives poor precision and recovery because of dimer formation. For formaldehyde, acetaldehyde, and acetone, both the precision (7.30, 2.49, 2.88% relative standard deviation, respectively) and recovery (90.0, 95.2, 102.8%, respectively) are acceptable. The response for formaldehyde, acetaldehyde, and acetone is linear and a function of the number of cigarettes smoked. The minimum detectable quantity for the analytes ranges from 5 to 16 micrograms per cigarette.
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