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Biomedical subjects

A Boon

Publications and source records attributed to A Boon.

At least 19 recordsLinked to original sources
PubMed2006

Cryptic mosaicism for monosomy 20 identified in renal tract cells.

We report a post-natal case of mosaic aneuploidy for chromosome 20 in a 4 months old male baby with an abnormal phenotype including dysmorphic features (asymmetric facial growth), ventricular septal defect, hypotonia and bilateral vesicoureteric reflux. Conventional cytogenetics on peripheral blood showed 1 cell of 200 with 47,XY,+20. Further investigations using fluorescent in situ hybridization (FISH) on a urine sample, with a centromere probe for chromosome 20, revealed 39 of 50 cells giving one signal indicative of monosomy 20. FISH analysis of a buccal smear was consistent with disomy 20 as was conventional cytogenetics on skin fibroblasts. This is the fourth reported case of mosaic monosomy 20, the second case where monosomy 20 is present with a trisomy 20 cell and the first case with each aneuploidy found in two separate tissues. The identification of mosaicism is a difficult task since the abnormal cells can be present only in certain tissues and may disappear with selection as the fetus develops, thus leading to single-cell abnormalities that may get dismissed (pseudomosaicism). The use of FISH in this case was crucial in identifying the cryptic mosaic monosomy 20 cell line. The likely mechanism of origin is post-zygotic nondisjunction giving rise to monosomy, disomy and trisomy cell(s) in the same or different tissues. Although no other trisomy 20 cells were found, the abnormal phenotype plus the finding of a monosomy 20 cell line make this mechanism the most plausible explanation. Had we dismissed the single-cell abnormality, the cryptic mosaicism of monosomy 20 would not have been identified. A detailed analysis of all tissues accessible in conjunction with careful consideration of all clinical information available is the best course of action in suspected mosaicism.

Abnormalities, Multiple↗
PubMed2005

Fatal haemothorax following large-bore percutaneous cannulation before liver transplantation.

Percutaneous bypass catheters are routinely used for veno-venous bypass (VVBP) during orthotopic liver transplantation (OLT). The recognized risks include bleeding, injury of vascular and nerve structures and lymphatic leakage. We describe a case where there were difficulties during catheterization and the patient suffered a cardiac arrest on commencing VVBP. Post-mortem examination revealed the bypass catheter tip in the pleural space and a large right haemothorax. Possible mechanisms of vascular perforation and preventative measures are discussed.

Catheterization, Central Venous↗
PubMed2005

Cutaneous granulomas associated with primary immunodeficiency disorders.

Cutaneous granulomas are uncommon in primary immunodeficiency disorders. We report cutaneous granulomas in a child with ataxia telangiectasia (AT) and compare the clinical course with similar lesions in an adult with common variable immunodeficiency (CVI). A 4-year-old female with AT developed cutaneous granulomas as erythematous plaques. The largest lesion appeared on her left cheek and continued to progress despite treatment with topical and intralesional steroids. Disease control was obtained initially with oral antibiotics and low-dose oral steroids. On cessation of oral steroids, significant relapse of the facial granuloma occurred. Pulsed and then oral steroids were required to stop the disease process leaving significant scarring. The second case is of cutaneous granulomas in a 66-year-old man, with CVI, who presented with an erythematous reticulate rash on the legs. We consider it useful to report this patient here as disease control was obtained in a similar way with systemic immunosuppression. In this patient a combination of oral steroids and azathioprine was used. These cutaneous granulomas are thought to be a manifestation of immune dysregulation. No infectious cause has been found so far. We recommend the use of broad-spectrum antibiotics in conjunction with systemic steroids for progressive granulomas, as these patients are immunosuppressed and infection with an unidentified organism cannot be excluded.

Aged↗
PubMed1997

Mitral annulus calcification is not an independent risk factor for stroke: a cohort study of 657 patients.

All studies but one in the past have shown a strong relative risk of mitral annulus calcification for stroke, but the contribution of associated cardiac and vascular risk factors, especially carotid atheroma has not been appreciated. We studied the risk of stroke in selected patients with mitral annular calcification, adjusting for clinical, echocardiographic and therapeutic factors influencing stroke risk. Of 8,160 consecutive patients with echocardiograms, 657 with and 562 without mitral annulus calcification were followed for a mean of 2.4 years (range 1-6.6) to determine stroke risk by means of proportional hazards models with clinical, echocardiographic, and therapeutic variables that influence the risk of stroke. We also determined the association of mitral annulus calcification with subtypes of ischaemic brain lesions generally considered to be specific for an underlying cardioembolic cause. We therefore distinguished between territorial, small deep, and asymptomatic (silent) brain infarcts. Fifty-one patients with mitral annulus calcification and 27 controls had a stroke in the follow-up period. Mitral annulus calcification was not significantly associated with stroke in proportional hazards models (hazard ratio 0.76, 95% confidence interval 0.42-1.36, P = 0.3), or with any of the stroke subtypes, or with the presence of silent brain infarcts after adjustments for risk factors for generalized vascular disease Hypertension and carotid atheroma, with or without stenosis, ipsilateral or contralateral to the side of the stroke, were significantly associated with stroke in our patients. This study does not support the view that mitral annulus calcification is a risk factor for stroke. As others have found strong associations between mitral annulus calcification and cardiac and vascular risk factors for stroke, the increased risk of stroke in patients with mitral annulus calcification reported may be explained by these confounding risk factors. Therefore, in our opinion, mitral annulus calcification requires treatment of cardiovascular risk factors, but generally no specific measures such as surgery or oral anticoagulants are required to lower the risk of stroke.

Aged↗
PubMed1997

Cardiac valve calcification: characteristics of patients with calcification of the mitral annulus or aortic valve.

AIMS: To determine whether mitral annular calcification and aortic valve calcification, with or without stenosis, are expressions of atherosclerotic disease. METHODS: The incidence of atherosclerotic risk factors was analysed in patients with mitral annular calcification and aortic valve calcification and in control patients from a prospective echocardiographic database of 8160 consecutive patients; 657 patients (8%) were identified with mitral annular calcification and 815 (9%) with a calcified aortic valve, of whom 515 (6.3%) had stenosis with a minimal aortic valve gradient of 16 mm Hg. In these patients, cardiac and vascular risk factors were compared with 568 control patients using multiple logistic regression analysis. RESULTS: Age (odds ratio (OR) varying from 5.78 to 104, depending on age class), female sex (OR 1.75), hypertension (OR 2.38), diabetes mellitus (OR 2.85), and hypercholesterolaemia (OR 2.95) were strongly and significantly associated with aortic valve calcification without stenosis, as were age (OR varying from 8.82 to 67, depending on age class), female sex (OR 2.22), hypertension (OR 2.72), diabetes mellitus (OR 2.49), and hypercholesterolaemia (OR 2.86) with mitral annular calcification. Age (OR varying from 1.11 to 7.7), hypertension (OR 1.91), and hypercholesterolaemia (OR 2.55) were strongly and significantly associated with stenotic aortic valve calcification. CONCLUSIONS: Mitral annular calcification and stenotic or non-stenotic aortic valve calcification have a high incidence of atherosclerotic risk factors, suggesting they should be considered as manifestations of generalised atherosclerosis.

Adult↗
PubMed1996

Risk of stroke in a cohort of 815 patients with calcification of the aortic valve with or without stenosis.

BACKGROUND AND PURPOSE: We sought to establish the possible role of calcification of the aortic valve with or without stenosis as a risk factor for stroke. METHODS: Occurrences of stroke, stroke subtypes, and concomitant cardiovascular risk factors were prospectively analyzed in 300 patients with echocardiographic evidence of aortic valve calcification, 515 patients with calcified aortic valve stenosis, and 562 control subjects. RESULTS: Twenty-four patients with aortic valve calcification, 24 patients with calcified aortic valve stenosis, and 27 control subjects had a stroke during follow-up. Using Cox proportional hazards models, we found that strokes were not significantly associated with aortic valve calcification with or without stenosis, but hypertension and any carotid stenosis were associated. On multiple logistic regression analysis, we did not find any association between one of the two valve lesions and indirect possible indications of cardiogenic embolism such as territorial as opposed to small deep brain infarcts or the presence of silent brain infarcts. CONCLUSIONS: Aortic valve calcification with or without stenosis is not a risk factor for stroke.

Age Factors↗
PubMed1994

Silent brain infarcts in 755 consecutive patients with a first-ever supratentorial ischemic stroke. Relationship with index-stroke subtype, vascular risk factors, and mortality.

BACKGROUND AND PURPOSE: We wanted to establish independent associations of various clinical variables, computed tomographic (CT) scan features, presenting stroke subtypes, and outcome with the presence of silent infarcts on CT. METHODS: We studied 755 consecutive patients in a prospective registration of patients with first-ever supratentorial atherothrombotic, cardioembolic, or lacunar stroke or stroke of undetermined cause by multiple logistic regression analysis. RESULTS: Two hundred six patients (27%) with a first symptomatic territorial or small deep ischemic stroke had one or more silent infarcts on CT. Of all silent lesions, 169 (82%) were small and deep. Silent infarcts were significantly more strongly associated with a lacunar than atherothrombotic (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.02 to 2.47; P = .039) or cardioembolic (OR, 1.89; 95% CI, 1.2 to 2.99; P = .005) index stroke. Silent territorial lesions were more strongly associated with cardioembolic than with lacunar stroke but not with atherothrombotic stroke. In this respect, no differences were found between the atherothrombotic and undetermined-cause group. Advanced age and hypertension were the only risk factors that were significantly associated with silent infarcts (OR, 1.76; 95% CI, 1.14 to 2.71; P = .011; and OR, 1.58; 95% CI, 1.13 to 2.21; P = .007; respectively), mainly because of a strong independent association of these risk factors with silent small deep infarcts (OR, 1.75; 95% CI, 1.10 to 2.79; P = .018; and OR, 1.57; 95% CI, 1.09 to 2.24; P = .014; respectively). A cardioembolic source or atrial fibrillation in specific was not independently associated with any type or number of silent infarcts. Significant carotid stenosis (diameter reduction > 50%) was not significantly associated with any type of silent lesion. Initial severe handicap (Rankin Scale score > 3), 30-day case fatality rate, and 1-year mortality were not affected by the presence of silent infarcts. CONCLUSIONS: The strong association of silent small deep lesions with first symptomatic small deep infarcts suggests a common underlying mechanism (presumably small-vessel vasculopathy), whereas cardiogenic embolism and large-vessel thromboembolism are the most likely causes in both silent and first symptomatic territorial infarcts. Single or multiple silent infarcts do not predict a cardioembolic stroke mechanism in first symptomatic supratentorial brain infarcts. As silent infarcts do not predict the cause of carotid embolic stroke in first symptomatic brain infarcts, their presence should not influence the decision on carotid surgery. Silent infarcts do not affect the degree of initial handicap, 30-day case fatality, or 1-year mortality. The significance of silent infarcts for predicting possible future cognitive decline and risk of recurrent stroke deserves further study.

Adult↗
PubMed1988

Maternal fatness and viability of preterm infants.

To investigate the effect of maternal fatness on the mortality of infants born preterm up to the corrected age of 18 months 795 mother-infant pairs were studied. Maternal fatness was defined by Quetelet's index (weight/(height] and all infants weighed less than 1850 g at birth. In 771 mother-infant pairs maternal age, complications of pregnancy, mode of delivery, parity, social class, and the baby's sex and gestation were analysed by a logistic regression model for associations with infant mortality (but deaths from severe congenital abnormalities and those occurring during the first 48 hours after birth were excluded). In a subgroup of 284 mother-infant pairs all infant deaths except those from severe congenital abnormalities were analysed in association with the infant's birth weight and gestation and the mother's height and weight; this second analysis included another 24 infants who had died within 48 hours after birth. In the first analysis mortality overall was 7% (55/771), rising from 4% (71/173) in thin mothers (Quetelet's index less than 20) to 15% (6/40) in mothers with grades II and III obesity (Quetelet's index greater than 30). After adjusting for major demographic and antenatal factors, including serious complications of pregnancy, maternal fatness was second in importance only to length of gestation in predicting death of infants born preterm. In the second analysis mortality overall was 15% (44/284), rising from 9% (5/53) in thin mothers to 47% (8/17) in mothers with grades II and III obesity. In both analyses the relative risk of death by 18 months post-term was nearly four times greater in infants born to obese mothers than in those born to thin mothers. In addition, maternal fatness was associated with reduced birth weight, whereas it is associated with macrosomia in term infants. These data differ fundamentally from those reported in full term babies of obese mothers. It is speculated that the altered metabolic milieu in obesity may reduce the ability of the fetus to adapt to extrauterine life if it is born preterm.

Adult↗
PubMed1988

Factors associated with maternal choice to provide breast milk for low birthweight infants.

Factors associated with maternal choice to provide milk for premature infants were investigated in 925 mother/infant pairs in five hospitals. A well educated, married, primiparous mother aged 20 or over who delivered a baby boy by caesarean section was nearly 1000 times more likely to choose to express her milk than a mother who was poorly educated, single, multiparous, and aged under 20, delivering a female infant vaginally. Evidence from the five centres suggested that hospital staff have little influence on a mother's choice of feeding method. The major differences between the populations of babies whose mothers do or do not choose to provide milk, raise important issues concerning the interpretation of data from non-randomised clinical trials of feeding premature infants.

Birth Order↗
PubMed1988

Early sodium intake and later blood pressure in preterm infants.

The relation between early salt intake and later hypertension is debated. As part of a larger feeding study, 347 preterm infants were randomly assigned to receive early diets differing grossly in sodium content. Feeding a high sodium preterm formula in the neonatal period did not influence arterial blood pressure at 18 months (corrected) age.

Blood Pressure↗
PubMed1987

Neurological complications following liver transplantation.

17 (33%) of 52 patients who underwent 56 consecutive orthotopic liver transplants had serious neurological complications postoperatively. The commonest complication was fits, which occurred in 13 (25%) patients. 50% of patients had their onset of fits within the first week. In 3 patients the fits were associated with postoperative metabolic encephalopathy and fatal progressive neurological deterioration. In some patients the evidence implicating cyclosporin in the development of fits is strong. In others factors such as electrolyte disturbances, steroid treatment for graft rejection, and cerebral infarction may have contributed to the development of the fits. Phenytoin controlled the fits in 10 out of 13 patients. Other neurological complications included 1 case of central pontine myelinolysis, 1 of cerebral abscess, and 4 of non-encephalopathic psychosis.

Adolescent↗
PubMed1985

Radiation-induced changes in the cell membrane of cultured human endothelial cells.

We investigated the effect of irradiation on the kinetic characteristics of amino acid and glucose transport, and the effect on the activity of the cell membrane-bound enzyme 5'-nucleotidase and on the receptor-mediated stimulation of cyclic adenosine monophosphate synthesis by prostaglandin E1. Irradiation inhibited the sodium-dependent amino acid transport by a reduced binding of the amino acid to the transport unit. The transport of glucose, which appeared to be a sodium-independent process, was temporarily stimulated by increased maximal velocity of the transport. No effect was found on the binding to the transport unit. Irradiation increased the 5'-nucleotidase activity and decreased the prostaglandin E1-stimulated cyclic adenosine monophosphate synthesis 48 h after exposure to 20 Gy. It is concluded that irradiation decreases sodium-dependent transport by impairment of the transport unit, does not impair a sodium-independent process, and has opposite effects on membrane-bound enzyme activity and a receptor-mediated process.

5'-Nucleotidase↗