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Biomedical subjects

D Shaw

Publications and source records attributed to D Shaw.

At least 19 recordsLinked to original sources

Effect of Rb+ on cromakalim-induced relaxation and ion fluxes in guinea pig trachea.

The effects of cromakalim, verapamil and salbutamol have been examined in guinea pig trachealis smooth muscle in both Krebs physiological salt solution and Krebs solution where K+ has been replaced by Rb+. Cromakalim-induced relaxation in the presence of Rb+ was reduced in extent and became transient, whilst the relaxation response to verapamil was enhanced and that to salbutamol unaffected. The transient relaxation occurring in Rb+ was blocked by quinidine and glibenclamide. The presence of extracellular Rb+ also prevented cromakalim-stimulated efflux of both 86Rb+ and 42/43K+. There was, however, no effect on cromakalim-stimulated 86Rb+ uptake. It is proposed that cromakalim is opening two populations of potassium channel in guinea pig tracheal smooth muscle, one of which is susceptible to blockade by Rb+ and one of which is not. The latter channel appears to play the dominant role in cromakalim-stimulated uptake, and is responsible for the transient relaxation response in the presence of rubidium, whilst the former is responsible for the maintained relaxation.

Albuterol

Mycobacterium bovis (BCG) vaccination. Progressive disease in a patient asymptomatically infected with the human immunodeficiency virus.

OBJECTIVE: To report a case of progressive disease caused by Mycobacterium bovis after BCG vaccination in a patient asymptomatically infected with the human immunodeficiency virus (HIV). CLINICAL FEATURES: A 34-year-old white man about to commence employment as a developmental care worker had a BCG vaccination. Five months later, he had a positive result to a serological test for HIV antibody. Nine months after BCG vaccination, he presented with fever (38.7 degrees C), a large left axillary lymph node and a small left pleural effusion. The lymph node was biopsied and acid-fast bacilli observed in Ziehl-Neelsen stained smears. Culture grew Mycobacterium bovis (BCG). TREATMENT AND OUTCOME: He was successfully treated with isoniazid, rifampicin and ethambutol for a period of nine months. CONCLUSION: BCG vaccination of asymptomatic HIV-positive patients is not recommended. The detection of those at risk for HIV infection before vaccination administration is essential. Self-exclusion based on information supplied to all potential recipients is likely to be the most effective method.

Adult

Characterization of a YAC and cosmid contig containing markers tightly linked to the myotonic dystrophy locus on chromosome 19.

Myotonic dystrophy (DM) is caused by a defect in an unknown gene that maps to 19q13.3, flanked by the tightly linked markers ERCC1 on the proximal side and D19S51 on the distal side. We report the isolation and characterization of overlapping YAC and cosmid clones around D19S51 for the construction of a physical map around this locus. The resulting contig contains the markers D19S51 and D19S62 (another new marker tightly linked to the DM locus) and the distal breakpoint of a radiation hybrid cell line used in the physical mapping of the DM region. We have compared the restriction maps of the YACs and cosmids with that of the genome to investigate the fidelity of these clones.

Base Sequence

Oxygen therapy in sickle cell disease.

The effect of oxygen therapy on the number of irreversibly (ISC) and reversibly (RSC) sickled cells was studied in patients with sickle cell anemia. Inhalation of 50% oxygen in patients who were not in crisis produced a significant fall in RSCs and a lesser fall in ISCs. Twenty-five subjects in sickle cell crisis were chosen at random to receive either oxygen (15 patients) or air (10 patients). Those who received oxygen showed a significant reduction in RSCs, but not in ISCs. No significant change in RSCs or ISCs occurred in the group who received air. Despite the reduction in RSCs in the oxygen-treated group, there was no significant difference between the air and oxygen groups in the duration of severe pain, opioid administration, and hospitalization. It was also observed that crisis was associated with arterial desaturation and a reduction in the number of RSCs. We conclude that, although RSCs may be involved in the pathophysiology of sickle cell crisis, reduction in RSCs by oxygen therapy in these studies did not result in any reduction in the duration of crisis.

Adolescent

Chorionic villus sampling: analysis of fetal losses to delivery, placental pathology, and cervical microbiology.

A population of 1639 patients were seen for chorionic villus sampling (CVS). Embryonic death was identified at ultrasound in 5.3 per cent of patients. The number of patients undergoing CVS was 1551, with 1416 transcervical procedures and 135 transabdominal procedures. The most common indication for CVS was advanced maternal age. Spontaneous pregnancy losses identified by increased risk of pregnancy loss with increasing aspiration attempts. The total fetal loss for this population was 5.4 per cent with the pregnancy loss estimated due to procedure being 1.2 per cent. Analysis of placentae from patients having CVS and amniocentesis showed no differences. Microbiological assessment prior to CVS was similar to previous publications.

Adult

Human glandular Kallikrein genes: genetic and physical mapping of the KLK1 locus using a highly polymorphic microsatellite PCR marker.

We describe a highly polymorphic microsatellite repeat sequence, KLK1 AC, which is located 3' to the human glandular kallikrein gene (KLK1) at 19q13.3-13.4. A multiplex PCR was developed to simultaneously genotype the KLK1 AC repeat length polymorphism and a similar repeat at the adjacent APOC2 locus at 19q13.2. Genotypes from these two loci in the 40 large kindred pedigrees from the Centre d'Etude du Polymorphisme Humain were used in conjunction with the background genetic map to establish a multipoint linkage map. The KLK1 locus was also localized physically using somatic cell hybrid DNA templates for polymerase chain reaction analysis. Both genetic and physical mapping studies are consistent with the assignment cen-APOC2-KLK1-D19522-qter. The linkage map places KLK1 approximately 10 cM distal to APOC2. These markers therefore flank the myotonic dystrophy gene and may be useful for diagnosis.

Alleles

Norepinephrine in acute exacerbations of chronic schizophrenia. Negative symptoms revisited.

In recent years the dopamine hypothesis has failed to explain the complexities of schizophrenia. Because both negative symptoms and noradrenergic activity appear to increase with psychotic relapse, we studied negative symptoms, psychosis, cerebrospinal fluid norepinephrine, and cerebrospinal fluid monoamine metabolites in 32 male patients with a DSM-III diagnosis of schizophrenia while both receiving and not receiving long-term haloperidol treatment. Drug-free cerebrospinal fluid norepinephrine and 3-methoxy-4-hydroxyphenylglycol levels correlated significantly with the severity of negative symptoms and psychosis ratings. When the patients were divided into those who did and did not relapse while not receiving the drug, significant positive correlations between negative symptoms and cerebrospinal fluid norepinephrine and 3-methoxy-4-hydroxyphenylglycol were observed only in the patients who relapsed. Non significant but negative correlations were observed between the same variables in the nonrelapsers. Thus, increased norepinephrine activity in drug-free patients is associated with intensification of schizophrenic symptoms without necessarily causing the symptoms.

Acute Disease

Oleander poisoning.

The two common oleanders, Thevetia peruviana and Nerium oleander, contain a mixture of poisons including cardiac glycosides, and are extremely toxic. They are cultivated universally throughout Australia, and rank equally with mushrooms as the major cause of children's admission to hospital after accidental plant ingestions. A seven-year total population survey from south-east Queensland has revealed that, in practice, the rate of clinical poisoning due to oleander is inconsequential, and mortality is negligible. The annual age-specific admission rate for children (aged from birth to 12 years of age), for all plant ingestions is 2.33 per 100 000, and 0.62 per 100 000 specifically for oleander. Oleander ingestion causes a syndrome of combine cardiac and gastrointestinal symptoms and signs. A case series of 13 children is described, and the clinical features summarized. After accidental oleander ingestion, current experience indicates that the prognosis is excellent.

Antidotes

Thrombocytosis, thrombocythaemia and iron deficiency in patients with polycythaemia vera.

6 patients with polycythaemia vera who also developed concomitant iron deficiency are reported. When oral iron therapy was given, there was a marked reduction in the previously elevated platelet counts in 4 patients; during 2-9 years of observation of these patients there was a significant inverse relationship between haemoglobin concentration and platelet count. In the other 2 patients the elevated platelet counts did not fall when iron therapy was given. The significance of these different patterns of response in relation to the causal mechanism of elevated platelet counts in patients with polycythaemia vera is discussed.

Aged

Benzopyrones. 14. Synthesis and antiallergic properties of some N-tetrazolylcarboxamides and related compounds.

A series of chromones containing an acidic group has been synthesized and screened for the ability to inhibit passive cutaneous anaphylaxis and the release of histamine from mast cells of the rat. Many of the chromones contain the N-(5-tetrazolyl)carboxamido group, a novel source of acidity. Others contain a carboxyl, C-(5-tetrazolyl), 5-(4H)-oxotetrazolinyl, or N-(5-tetrazolyl)sulfonamido function. The compounds were compared with cromolyn sodium (sodium cromoglycate) and many were found to be powerful inhibitors of anaphylaxis. The most potent was 7-methoxy-4-oxo-N-(5-tetrazolyl)-4H-1-benzopyran-2-carboxamide (15). Structure-activity relationships among the chromones and also some related compounds are discussed.

Anaphylaxis