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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 181 records · Page 10Linked to original sources
PubMed1999

A rationalised virological electron microscope specimen testing policy. PHLS North West Viral Gastroenteritis and Electron Microscopy Subcommittee.

The aim of this project was to produce guidance for a rationalised virological electron microscopy specimen testing policy for PHLS North West, to facilitate centralisation of a groupwide diagnostic electron microscopy service on a single site. Careful specimen selection to limit numbers and the groupwide use of commercially available enzyme immunoassays has allowed PHLS North West to reduce the number of specimens prepared for electron microscopy. The rationalised virological electron microscopy specimen testing policy has enabled a diagnostic electron microscopy service to be provided from a single site with a manageable workload. Implementation of this specimen testing policy by PHLS North West has been successful and may be applicable to other laboratories (or groups of laboratories) to maximise the use of expensive electron microscopy facilities.

Aged↗
PubMed1999

Classical Friedreich's ataxia and its genotype.

Fourteen patients with classical features of Friedreich's ataxia (FRDA) were examined. The clinical diagnosis of FRDA was afterwards confirmed in all patients by the appropriate DNA investigation which showed markedly increased amounts of GAA repeats on both alleles of the frataxin gene. None of our patients presented with atypical features such as late-onset FRDA, FRDA with retained deep tendon reflexes or with a very slow course. Five of them are not yet confined to a wheelchair. But for 1 patient who died at age 36 years and had the largest number of GAA repeats on both alleles, there was no significant correlation between number of repeats in the shortest allele, age at onset, age at wheelchair dependence, duration of the disease and main clinical signs. All patients but 3 had between 500 and 1,050 GAA repeats. The 3 patients with, respectively, 400, 450 and 500 repeats on the shortest allele had a clinical course comparable to the other patients. Even in the case of variations in the number of repeats in the same sibship, there were only modest differences between the siblings concerning age at onset of the disease, symptoms and signs and age at wheelchair dependence. There were no qualitative differences in the main clinical features and laboratory investigations in the full-blown phase of the disorder. Molecular biology has become a major element in the diagnosis of FRDA. DNA testing for FRDA should be applied to every case of idiopathic autosomal recessive or sporadic ataxia. However, the clinical features of FRDA remain fully characteristic in many patients and keep their diagnostic value.

Adolescent↗
PubMed1999

A phase II trial of interferon alpha-2a and carboplatin in patients with advanced malignant mesothelioma.

We defined the antitumor activity, toxicity, and tolerability of a combined chemoimmunotherapy approach in patients with advanced malignant mesothelioma using daily low-dose interferon alpha-2a and carboplatin given every 4 weeks. This was a phase II study of 15 patients with surgically unresectable or metastatic malignant mesothelioma. All patients had measurable or assessable disease. No prior chemotherapy or immunotherapy was allowable. Carboplatin was given at 150 mg/m2 daily on days 1-3 and interferon alpha-2a at 3 million units subcutaneously daily throughout the study. Treatment was recycled every 28 days. Therapy was continued until disease progression. Fifteen patients were assessable for toxicity and 14 for response. One partial response (7%, 95% CI, 0-20%), with a response duration of 40 weeks, was seen. Most patients had early progression of disease. Toxicity was tolerable, and grade III/IV toxicity was uncommon. The median time to progression was 14 weeks (range, 1-52 weeks). The median survival was 25 weeks (range, 8-66 weeks). The combination of low-dose interferon alpha-2a and carboplatin did not result in greater antitumor activity than that reported for single-agent carboplatin in advanced malignant mesothelioma. Although toxicity was mild, carboplatin and low-dose interferon, given at this dose and schedule, cannot be recommended for this patient group.

Aged↗
PubMed1999

[Cutaneous periarteritis nodosa: diagnostic and therapeutic aspects of 9 cases].

BACKGROUND: Cutaneous periarteritis nodosa (PAN) is distinguished from systemic PAN by the lack of visceral involvement. The aim of this study was to describe the clinical presentation, laboratory findings, clinical course, and treatment in cutaneous PAN. PATIENTS AND METHODS: We retrospectively reviewed the files of patients hospitalized for vasculitis in our Dermatology unit where approximately 20 cases of vasculitis are seen each year. Inclusion criteria were skin signs suggestive of PAN and a histological image of leukocytoclastic vasculitis of an arteriole. RESULTS: Nine cases of cutaneous PAN were treated in our unit between 1976 and 1997. Follow-up ranged from 32 months to 22 years. No cases of systemic PAN had been diagnosed during this period. These 9 cases of cutaneous PAN all had the same clinical presentation: nodules on the lower limbs in all cases associated with nodules on the upper limbs in half of the cases. Neuropathy was found in 3 of the 9 cases. No systemic involvement was observed. The most frequently used treatment protocol was general corticosteroid therapy (0.5 mg/kg/d prednisone or prednisolone). Immunosuppressive drugs, colchicine, dapsone, non-steroidal anti-inflammatory drugs and intravenous immunoglobulins were also used with efficacy. DISCUSSION: Cutaneous PAN is a particular form of vasculitis associating skin signs with locoregional neuromuscular involvement. The differential diagnosis with other types of vasculitis is sometimes a difficult task. The clinical course is the fundamental diagnostic clue in cutaneous PAN. A benign course and the absence of visceral involvement allow initiating a symptomatic treatment such as colchicine. The development of neuromuscular signs may warrant the use of general corticosteroid therapy.

Adrenal Cortex Hormones↗
PubMed1999

[Pre-capillary pulmonary hypertension complicating CREST syndrome. Apropos of a case].

Pre-capillary pulmonary hypertension was the presenting sign of a CREST syndrome in a 65 year old woman. The diagnosis of this form of scleroderma is based on the association of a number of features (calcinosis, Raynaud's phenomenon, oesophageal dyskinesia, sclerodactylia and telangectasia). Scleroderma is the systemic disease which is usually complicated by pre-capillary pulmonary hypertension. This complication is observed in about 13% of CREST syndromes, but very rarely as severe pre-capillary pulmonary hypertension. The diagnosis of pre-capillary pulmonary hypertension carries a poor prognosis with a 2 year survival rate of about 40%. Treatment is usually with calcium inhibitors but with no effect on prognosis. The use of prostacycline and its analogue, iloprost, is an interesting therapeutic strategy, currently under evaluation. Cardiopulmonary transplantation is the only treatment of very severe forms, despite the progressive character of the condition. All cases of pre-capillary pulmonary hypertension require complete aetiological investigation to exclude a systemic disease, especially a scleroderma and, above all, a CREST syndrome.

Aged↗
PubMed1999

Are there several types of colorectal carcinomas? Correlations with genetic data.

Molecular studies have shown that different genetic pathways are involved in the history of colorectal carcinomas. This suggests that a correlation exists between the molecular, clinical and pathological features of tumours. Two large groups can be individualized: the first group is characterized by allelic losses and hyperdiploidy. These LOH (for loss of heterozygosity)-positive tumours represent 80% of colorectal carcinomas. Among them more than two-thirds are located in the distal colon. They have the worst prognosis. The second group has a normal diploid pattern and a phenotypic microsatellite instability without allelic losses. These tumours represent 10-15% of all colorectal carcinomas and about 30% of the right-sided tumours. They are associated with a better prognosis. In the future, it would perhaps be better to classify colorectal carcinomas according to their molecular features rather than to their topographical localizations.

Carcinoma↗
PubMed1998

Serum hyaluronic acid in Down's syndrome.

In agreement with previous studies we show an age-related increase in serum levels of hyaluronic acid in healthy individuals. Levels in Down's syndrome persons were slightly higher, especially in those with hypothyroidism. This provides further evidence that the normal ageing process is accelerated in Down's syndrome.

Adult↗
PubMed1998

Germ cell-specific enhancer activity of a repeated element in a variable region of the mouse genome.

We recently described a complex genetic structure on mouse chromosome 8, a region of the murine genome in which genetic rearrangements frequently occur. A large repeated element specific to this chromosome was found to overlap with one of the cadherin genes (Cad11). An additional degree of complexity became apparent with the identification, in a subset of laboratory strains of mice, of a retrogene integrated into one of the repeated units. Designated Sycp1-ps2, it originated from the early meiotic gene encoding Synaptonemal Complex Protein 1. We now report that, among wild Mus species in which the retrogene is not present, this region of Chr 8 shows a high degree of variability. Sequence analysis showed that integration of Sycp1-ps2 created a 5' transcription initiator element. Transcription of the pseudogene in the testis was directly demonstrated. A germ cell-specific enhancer activity was localized within a 1117 bp region of the repeat, which was sufficient to direct the expression of reporter genes in transgenic mice to late meiotic and post-meiotic spermatogenic cells.

Animals↗
PubMed1998

Beta-amino-thiols inhibit the zinc metallopeptidase activity of tetanus toxin light chain.

Tetanus neurotoxin is a 150-kDa protein produced by Clostridium tetani, which causes the lethal spastic paralytic syndromes of tetanus by blocking inhibitory neurotransmitter release at central synapses. The toxin light chain (50 kDa) has a zinc endopeptidase activity specific for synaptobrevin, an essential component of the neuroexocytosis apparatus. Previous unsuccessful attempts to block the proteolytic activity of this neurotoxin with well-known inhibitors of other zinc proteases led us to study the design of specific inhibitors as a possible drug therapy to prevent the progressive evolution of tetanus following infection. Starting from the synaptobrevin sequence at the level of the cleavage site by tetanus neurotoxin (Gln76-Phe77), a thiol analogue of glutamine demonstrated inhibitory activities in the millimolar range. A structure-activity relationship performed with this compound led us to determine the requirement for the correct positioning of the thiol group, the primary amino group, and a carboxamide or sulfonamide group on the side chain. This resulted in the design of a beta-amino-(4-sulfamoylphenyl)glycine-thiol, the first significantly efficient inhibitor of tetanus neurotoxin with a Ki value of 35 +/- 5 microM.

Enzyme Inhibitors↗
PubMed1998

Large-scale preparation, purification, and crystallization of UDP-N-acetylmuramoyl-L-alanine: D-glutamate ligase from Escherichia coli.

The UDP-N-acetylmuramoyl-L-alanine:D-glutamate ligase from Escherichia coli, an enzyme involved in the biosynthesis of the bacterial peptidoglycan monomer unit, was overproduced and purified to homogeneity on a large scale, yielding 4 mg of protein per liter of bacterial culture. Crystals of the complex with the substrate UDP-MurNAc-L-Ala were grown by the hanging drop method using ammonium sulfate as the precipitant. They are tetragonal with cell dimensions a = b = 65.5 A and c = 134.59 A, space group P4(1) or P4(3), and contain one monomer of 46,842 Da in the asymmetric unit. In order to use the multiple-wavelength anomalous diffraction method for phasing, a selenomethionine derivative of the protein has also been overproduced, purified, and crystallized.

Amino Acid Sequence↗
PubMed1998

Long-term effects of childhood maltreatment history on gender-related personality characteristics.

OBJECTIVE: The aim of the study was to test the hypothesis that different types of gender-related personality attributes are associated with a past history of different types of childhood maltreatment. METHOD: A survey was administered to 1,060 male soldiers and 305 female soldiers in the U.S. Army. The survey instrument included the Extended Personal Attributes Questionnaire (EPAQ) which is a self-assessment instrument of personality characteristics associated with gender, and includes measures of positive masculinity (self-assertive/instrumental traits), positive femininity (expressive/interpersonal traits), negative masculinity (hyper masculine/macho traits), and negative femininity (subordination of self to others). The survey instrument also included the Childhood Trauma Questionnaire (CTQ), which contains scales measuring sexual abuse, physical-emotional abuse, physical neglect, and emotional neglect, and four questions on childhood sexual abuse developed for a national survey of U.S. adults. RESULTS: Negative masculinity was predicted by male gender, younger age, and childhood physical-emotional abuse. Negative femininity was predicted by physical-emotional abuse and sexual abuse. The relationship to sexual abuse was mainly evident for males. Positive femininity was positively correlated with sexual abuse for females and negatively correlated with sexual abuse for males. Positive masculinity was negatively correlated with emotional neglect for males but not for females. Positive femininity was negatively correlated with emotional neglect for both genders. CONCLUSIONS: Childhood abuse was associated with the presence of negative gender-related attributes; childhood neglect was associated with absence of positive gender-related attributes. Childhood physical abuse was associated with negative masculine attributes in both genders. Childhood sexual abuse was associated with positive feminine attributes in females, and negative feminine attributes in males. The finding for females is counterintuitive, and is discussed in the light of the clinical literature on certain types of adaptation to incest.

Adult↗
PubMed1998

-Pancreatitis after blunt injuries to the abdomen-.

Three cases of pancreatitis occurring after a trauma to the pancrease are reported. They emphasize the difficulty of diagnosis at the initial phase of the condition. In all cases, computerized tomography (CT) scan was the main diagnostic method. Applying the same therapeutic strategy for pancreatitis as for other aetiologies facilitated a favourable outcome.

Abdominal Injuries↗
PubMed1998

[Prolonged neuromuscular blockade with mivacurium in a newborn].

Mivacurium is a short acting non-depolarising neuromuscular blocking agent. Short duration of action is due to a rapid hydrolysis by plasma cholinesterase (CHe). The duration of neuromuscular blockade can be prolonged by an abnormal variant of CHe. We report a case of a newborn with neuromuscular blockade for a duration of 8 hours following mivacurium 0.2 mg.kg-1. CHe activity values were not contributive for the diagnosis. The diagnosis was obtained with molecular study showing the new-born homozygocity. The whole family was heterozygous. This case emphasises the lack of precision of CHe activity measurement during the first 6 months of life.

Cholinesterases↗