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S M White

Publications and source records attributed to S M White.

At least 37 records · Page 2Linked to original sources
PubMed2002

The Human Rights Act 1998: implications for anaesthesia and intensive care.

The Human Rights Act 1998 was incorporated into UK statutory law on October 2, 2000. The 18 Articles of the Act are likely to have a significant impact on the practice of medicine in the UK, particularly in reference to consent, disclosure of medical information and patient access to healthcare. This article examines the implications of the new legislation for anaesthetic and intensive care practice.

Anesthesiology↗
PubMed2002

Chemical and biological weapons. Implications for anaesthesia and intensive care.

In the wake of recent atrocities there has been renewed apprehension regarding the possibility of chemical and biological weapon (CBW) deployment by terrorists. Despite various international agreements that proscribe their use, certain states continue to develop chemical and biological weapons of mass destruction. Of greater concern, recent historical examples support the prospect that state-independent organizations have the capability to produce such weapons. Indeed, the deliberate deployment of anthrax has claimed several lives in the USA since September 11, 2001. In the event of a significant CBW attack, medical services would be stretched. However, victim survival may be improved by the prompt, coordinated response of military and civil authorities, in conjunction with appropriate medical care. In comparison with most other specialties, anaesthetists have the professional academic background in physiology and pharmacology to be able to understand the nature of the injuries caused by CBWs. Anaesthetists, therefore, play a vital role both in the initial resuscitation of casualties and in their continued treatment in an intensive care setting. This article assesses the current risk of CBW deployment by terrorists, considers factors which would affect the severity of an attack, and discusses the pathophysiology of those CBWs most likely to be used. The specific roles of the anaesthetist and intensivist in treatment are highlighted.

Anesthesia↗
PubMed2002

Preventive detention must be resisted by the medical profession.

A policy of "preventive detention" has recently been debated in the British Parliament. Alarmed by the high-profile criminal activities of people suspected of having dangerous severe personality disorder (DSPD), the government have made clear their intention to "indeterminately but reviewably detain" people with DSPD, after diagnosis by forensic psychiatrists, even if the individuals are yet to commit an offence. Such a policy may improve the safety of the public, but has obvious implications for civil liberties. This essay criticises the morality of the government's intention and rejects the notion that the medical profession could ethically collude with such a policy.

Attitude of Health Personnel↗
PubMed2002

Identification of a haplosufficient 3.6-Mb region in human chromosome 11q14.3-->q21.

Cytogenetic deletions are almost always associated with phenotypic abnormality and are very rarely transmitted. We have located a hitherto undescribed, familial deletion involving the region 11q14.3-->q21 in five individuals in a three-generation kindred. Four of the deletion carriers show no phenotypic abnormality; the other, who is the proband, was investigated for short stature and poor academic progress. In view of the apparent innocuous nature of this genetic imbalance, the deletion was investigated in detail to determine its size (3.6 Mb) and location with reference to molecular markers and genetic content. The deleted region is described by a contig of 37 BACS including the flanking regions, which we have assembled. Several possible contributory factors are considered, which might explain the lack of clinical significance of this large deletion. It is notable that there are few genes in this region and none have known functions. All most likely have copies elsewhere in the genome and a number of other hypothetical genes appear to be members of certain gene families, i.e. none is unique. Part of the region (1 Mb) is also duplicated at the pericentromeric region 11p11. Given the very low proportion of the genome occupied by single copy genes and their uneven distribution, regions such as this, which appear to be functionally haplosufficient, may be more common than hitherto recognised.

Chromosome Banding↗
PubMed2002

Miss B.

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Adult↗
PubMed2002

Sezary syndrome.

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Anesthesia, Epidural↗
PubMed2001

Safety evaluation of dietary aluminum.

Aluminum is a nonessential metal to which humans are frequently exposed. Aluminum in the food supply comes from natural sources, water used in food preparation, food ingredients, and utensils used during food preparations. The amount of aluminum in the diet is small, compared with the amount of aluminum in antacids and some buffered analgesics. The healthy human body has effective barriers (skin, lungs, gastrointestinal tract) to reduce the systemic absorption of aluminum ingested from water, foods, drugs, and air. The small amount of aluminum (<1%) that is systemically absorbed is excreted principally in the urine and, to a lesser extent, in the feces. No reports of dietary aluminum toxicity to healthy individuals exist in the literature. Aluminum can be neurotoxic, when injected directly into the brains of animals and when accidentally introduced into human brains (by dialysis or shrapnel). A study from Canada reports cognitive and other neurological deficits among groups of workers occupationally exposed to dust containing high levels of aluminum. While the precise pathogenic role of aluminum in Alzheimer's disease (AD) remains to be defined, present data do not support a causative role for aluminum in AD. High intake of aluminum from antacid for gastrointestinal ailments has not been reported to cause any adverse effects and has not been correlated with neurotoxicity or AD. Foods and food ingredients are generally the major dietary sources of aluminum in the United States. Cooking in aluminum utensils often results in statistically significant, but relatively small, increases in aluminum content of food. Common aluminum-containing food ingredients are used mainly as preservatives, coloring agents, leavening agents, anticaking agents, etc. Safety evaluation and approval of these ingredients by the Food and Drug Administration indicate that these aluminum-containing compounds are safe for use in foods.

Aluminum↗
PubMed2001

The effect of controlled drugs on the unborn child and fetus.

Illicit substance abuse is more prevalent than thought in women of a child bearing age and its incidence is increasing. Although maternal factors, such as poor socioeconomic status, diet, smoking, alcohol and infection, have detrimental effects on the fetuses of drug-abusing mothers, harm is increased due to the pharmacological activity of the drugs themselves. This article reviews the pharmacophysiological interactions between mother and fetus, describes the general effects of substance abuse during each trimester and details the deleterious effects on the fetus of the more commonly abused controlled drugs.

Journal Article↗
PubMed2001

In-phantom dosimetry for the 13C(d,n)14N reaction as a source for accelerator-based BNCT.

The use of the 13C(d,n) 14N reaction at Ed=1.5 MeV for accelerator-based boron neutron capture therapy (AB-BNCT) is investigated. Among the deuteron-induced reactions at low incident energy, the 3C(d,n)14N reaction turns out to be one of the best for AB-BNCT because of beneficial materials properties inherent to carbon and its relatively large neutron production cross section. The deuteron beam was produced by a tandem accelerator at MIT's Laboratory for Accelerator Beam Applications (LABA) and the neutron beam shaping assembly included a heavy water moderator and a lead reflector. The resulting neutron spectrum was dosimetrically evaluated at different depths inside a water-filled brain phantom using the dual ionization chamber technique for fast neutrons and photons and bare and cadmium-covered gold foils for the thermal neutron flux. The RBE doses in tumor and healthy tissue were calculated from experimental data assuming a tumor 10B concentration of 40 ppm and a healthy tissue 10B concentration of 11.4 ppm (corresponding to a reported ratio of 3.5:1). All results were simulated using the code MCNP, a general Monte Carlo radiation transport code capable of simulating electron, photon, and neutron transport. Experimental and simulated results are presented at 1, 2, 3, 4, 6, 8, and 10 cm depths along the brain phantom centerline. An advantage depth of 5.6 cm was obtained for a treatment time of 56 min assuming a 4 mA deuteron current and a maximum healthy tissue dose of 12.5 RBE Gy.

Boron↗
PubMed2001

Clinical studies on submicroscopic subtelomeric rearrangements: a checklist.

BACKGROUND: Submicroscopic subtelomeric chromosome defects have been found in 7.4% of children with moderate to severe mental retardation and in 0.5% of children with mild retardation. Effective clinical preselection is essential because of the technical complexities and cost of screening for subtelomere deletions. METHODS: We studied 29 patients with a known subtelomeric defect and assessed clinical variables concerning birth history, facial dysmorphism, congenital malformations, and family history. Controls were 110 children with mental retardation of unknown aetiology with normal G banded karyotype and no detectable submicroscopic subtelomeric abnormalities. RESULTS: Prenatal onset of growth retardation was found in 37% compared to 9% of the controls (p<0.0005). A higher percentage of positive family history for mental retardation was reported in the study group than the controls (50% v 21%, p=0.002). Miscarriage(s) were observed in only 8% of the mothers of subtelomeric cases compared to 30% of controls (p=0.028) which was, however, not significant after a Bonferroni correction. Common features (>30%) among subtelomeric deletion cases were microcephaly, short stature, hypertelorism, nasal and ear anomalies, hand anomalies, and cryptorchidism. Two or more facial dysmorphic features were observed in 83% of the subtelomere patients. None of these features was significantly different from the controls. Using the results, a five item checklist was developed which allowed exclusion from further testing in 20% of the mentally retarded children (95% CI 13-28%) in our study without missing any subtelomere cases. As our control group was selected for the "chromosomal phenotype", the specificity of the checklist is likely to be higher in an unselected group of mentally retarded subjects. CONCLUSIONS: Our results suggest that good indicators for subtelomeric defects are prenatal onset of growth retardation and a positive family history for mental retardation. These clinical criteria, in addition to features suggestive of a chromosomal phenotype, resulted in the development of a five item checklist which will improve the diagnostic pick up rate of subtelomeric defects among mentally retarded subjects.

Abnormalities, Multiple↗
PubMed2001

Calcium signaling pathways utilized by P2X receptors in freshly isolated preglomerular MVSMC.

This study tested the hypothesis that P2X receptor activation increases intracellular Ca(2+) concentration ([Ca(2+)](i)) in preglomerular microvascular smooth muscle cells (MVSMC) by evoking voltage-dependent calcium influx. MVSMC were obtained and loaded with the calcium-sensitive dye fura 2 and studied by using single-cell fluorescence microscopy. The effect of P2X receptor activation on [Ca(2+)](i) was assessed by using the P2X receptor-selective agonist alpha,beta-methylene-ATP and was compared with responses elicited by the endogenous P2 receptor agonist ATP. alpha,beta-Methylene-ATP increased [Ca(2+)](i) dose dependently. Peak increases in [Ca(2+)](i) averaged 37 +/- 11, 73 +/- 15, and 103 +/- 21 nM at agonist concentrations of 0.1, 1, and 10 microM, respectively. The average peak response elicited by 10 microM alpha,beta-methylene-ATP was approximately 34% of the response obtained with 10 microM ATP. alpha,beta-Methylene-ATP induced a transient increase in [Ca(2+)](i) before [Ca(2+)](i) returned to baseline, whereas ATP induced a biphasic response including a peak response followed by a sustained plateau. In Ca(2+)-free medium, ATP induced a sharp transient increase in [Ca(2+)](i), whereas the response to alpha,beta-methylene-ATP was abolished. Ca(2+) channel blockade with 10 microM diltiazem or nifedipine attenuated the response to alpha,beta-methylene-ATP, whereas nonspecific blockade of Ca(2+) influx pathways with 5 mM Ni(2+) abolished the response. Blockade of P2X receptors with the novel P2X receptor antagonist NF-279 completely but reversibly abolished the response to alpha,beta-methylene-ATP. These results indicate that P2X receptor activation by alpha,beta-methylene-ATP increases [Ca(2+)](i) in preglomerular MVSMC, in part, by stimulating voltage-dependent Ca(2+) influx through L-type Ca(2+) channels.

Adenosine Triphosphate↗
PubMed2001

Biological dosimetry for epithermal neutron beams.

The radiobiological effectiveness of an epithermal neutron beam is described using cell survival as the end point. The M67 epithermal neutron beam at the Nuclear Reactor Laboratory, Massachusetts Institute of Technology, that was used for clinical trials of boron neutron capture therapy was used to irradiate Chinese hamster ovary cells at seven depths in a water-filled phantom that simulated healthy tissue. No boron was added to the samples. Therefore, this experiment evaluates the biological effectiveness of the neutron and photon components, which comprise 80-95% of the dose to healthy tissue. Cell survival was dependent upon the depth in the phantom, as a result of moderation and attenuation of the epithermal neutron beam components by the overlying water. The results were compared with 250 kVp X irradiations to determine relative biological effectiveness values. Cell survival as a function of the dose delivered was lowest at the most shallow depth of 0.5 cm, and increased at depths of 1.5, 3, 4, 5.6, 6.6 and 8.1 cm. The gradual increase in cell survival with increasing depth in the phantom is due to the exponential drop of the fast-neutron intensity of the beam. These results are applicable to clinical boron neutron capture therapy Phase I/II trials in which healthy tissue toxicity was an end point.

Animals↗