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Biomedical subjects

G Serjeant

Publications and source records attributed to G Serjeant.

At least 37 records · Page 2Linked to original sources
PubMed1993

The clinical significance of serum transferrin receptor levels in sickle cell disease.

Serum transferrin receptor (TfR) levels were measured in 182 children with homozygous sickle cell (SS) disease, 47 with sickle cell-haemoglobin C (SC) disease and 41 normal (AA) controls on their eighth birthday. Highly significant elevations occurred in SS compared to SC disease and in SC disease compared to AA controls. Females had higher levels than males in controls but lower levels than males in SS and SC disease. In SS disease, serum TfR levels tended to rise with age from 2 to 8 years, the change within individuals correlating with a change in reticulocyte count (r = 0.38, P = 0.017) and fall in fetal haemoglobin levels (r = -0.51, P = 0.004). Serum TfR levels did not change with infection or painful crisis but were markedly elevated in hypersplenism and fell following splenectomy in these subjects. In the aplastic crisis, serum TfR levels tended to rise following clinical presentation and then fall, reflecting the reticulocyte counts. These observations are consistent with serum TfR levels being a useful indicator of the degree of erythropoietic expansion in sickle cell disease.

Age Factors↗
PubMed1992

Fetal hemoglobin levels in sickle cell disease and normal individuals are partially controlled by an X-linked gene located at Xp22.2.

Fetal hemoglobin (Hb F) production in sickle cell (SS) disease and in normal individuals varies over a 20-fold range and is under genetic control. Previous studies suggested that variant Hb F levels might be controlled by genetic loci separate from the beta-globin complex on chromosome 11. Using microscopic radial immunodiffusion and flow cytometric immunofluorescent assays to determine the percentage of F reticulocytes and F cells in SS and nonanemic individuals, we observed that F-cell levels were significantly higher in nonanemic females than males (mean +/- SD, 3.8% +/- 3.2% v 2.7% +/- 2.3%). F-cell production as determined by F reticulocyte levels in SS females was also higher than in SS males (17% +/- 10% v 13% +/- 8%). We tested the hypothesis that F-cell production in both normal and anemic SS individuals was controlled by an X-linked locus with two alleles, high (H) and low (L). Using an algorithm to determine the 99.8% confidence interval of a normal distribution in nonanemic individuals, we estimated that males and females with at least one H allele had greater than 3.3% F cells. Comparisons of male-male or female-female SS sib pairs with discordant F reticulocyte levels distinguished two phenotypes in SS males (L, less than 12%; H, greater than 12%) and three phenotypes in SS females (LL, less than 12%; HL, 12% to 24%, HH greater than 24%). Linkage analysis using polymorphic restriction sites along the X chromosome in eight SS and one AA family localized the F-cell production (FCP) locus to Xp22.2, with a maximum lod score (logarithm of odds of linkage v independent assortment) of 4.6 at a recombination fraction of 0.04.

Adult↗
PubMed1991

An update on techniques of photocoagulation treatment of proliferative sickle cell retinopathy.

Proliferative sickle cell retinopathy (PSR) can lead to visual loss from vitreous haemorrhage and traction or rhegmatogenous retinal detachment. We review two techniques of photocoagulation for PSR, feeder vessel photocoagulation and scatter photocoagulation. A prospective randomised trial of feeder vessel photocoagulation for PSR demonstrated that the incidence of vitreous haemorrhage and visual loss was diminished in eyes which were treated. Since this technique of treatment is difficult and can be associated with choroidal neovascularisation and retinal tears, scatter photocoagulation has also been tested. A prospective randomised trial of scatter photocoagulation for PSR demonstrated a decreased incidence of vitreous haemorrhage and visual loss in treated eyes compared to untreated eyes. No complications of scatter treatment were noted. We presently recommend local scatter photocoagulation to areas of PSR. In unreliable patients, we recommend 360 degrees of peripheral circumferential treatment as otherwise new seafans will develop. If scatter photocoagulation does not result in sufficient regression of the neovascularisation and vision threatening complications such as vitreous haemorrhage continue, feeder vessel treatment can be used to supplement the scatter treatment.

Anemia, Sickle Cell↗
PubMed1991

The haematology of homozygous sickle cell disease after the age of 40 years.

Haematological indices have been studied in 181 patients with homozygous sickle cell (SS) disease aged 40-73 years. Cross-sectional analyses in 5-year age bands indicated age-related decreases in HbF (males only), total haemoglobin and platelet counts. Longitudinal studies within individuals confirmed the downward age-related trend in haemoglobin and platelets and also revealed a falling reticulocyte count, most significant when expressed as absolute values. Total nucleated cells also fell although the decline was significant only in females. These observations are consistent with a progressive bone marrow failure which is not explained by the commonly occurring renal impairment in older SS patients since the changes persisted in analyses confined to patients with normal creatinine levels. The mechanism of this bone marrow failure is currently unknown.

Adult↗
PubMed1991

The red cell distribution width in sickle cell disease--is it of clinical value?

The red cell distribution width (RDW) has been studied during the clinical steady state in 1121 patients with homozygous sickle cell (SS) disease, 344 with sickle cell-haemoglobin C (SC) disease, 68 with sickle cell-beta+ thalassaemia, 49 with sickle cell beta 0 thalassaemia and in 130 control subjects with a normal (AA) genotype. The mean RDW was moderately increased in S beta + thalassaemia and SC disease and markedly increased in S beta 0 thalassaemia and SS disease. In SS, SC and S beta 0 thalassaemia genotypes, lower RDW values occurred in females and with alpha thalassaemia. The RDW correlated negatively with total haemoglobin, mean cell haemoglobin concentration, mean cell volume, and fetal haemoglobin (HbF) and positively with reticulocyte count in SS disease. A low RDW was associated with higher weight and less frequent dactylitis, painful crisis, acute chest syndrome, acute splenic sequestration, and hospital admissions. A low RDW in SS disease is consistent with a high total haemoglobin, high HbF, low reticulocyte count, alpha thalassaemia, and a more mild clinical course.

Adolescent↗
PubMed1987

Calcification of Bruch's membrane in angioid streaks with homozygous sickle cell disease.

Histochemical and light and electron microscopic studies of two eyes of a patient with homozygous sickle cell disease and angioid streaks demonstrated heavy calcification and breaks in Bruch's membrane. We were unable to demonstrate iron deposition by histochemical techniques or transmission electron microscopy. These studies suggest that calcification rather than iron deposition is the major factor leading to brittleness of Bruch's membrane in patients with hemolytic anemia and angioid streaks.

Anemia, Sickle Cell↗
PubMed1987

Neodymium-YAG laser vitreolysis in sickle cell retinopathy.

Six patients with proliferative sickle cell retinopathy and vitreous bands were treated with the neodymium-YAG (Nd-YAG) laser to accomplish lysis of avascular traction bands or to clear the media in front of the macula. Transection of bands was possible in five of the six cases but in two of these the effect was only partial. Three cases were satisfactorily treated with the Nd-YAG laser application alone, two eventually required conventional vitreoretinal surgery, and one patient's condition stabilized despite failure of the treatment. Complications from the treatment occurred in three cases and included subretinal (choroidal) hemorrhage, preretinal hemorrhage, microperforation of a retinal vein, and focal areas of damage to the retinal pigment epithelium. Neodymium-YAG vitreolysis may be a useful modality in carefully selected patients with proliferative sickle cell retinopathy, but potentially sight-threatening complications may occur.

Adult↗
PubMed1984

A randomized clinical trial of feeder vessel photocoagulation of proliferative sickle cell retinopathy. II. Update and analysis of risk factors.

Follow-up of patients enrolled in a randomized prospective trial of feeder vessel photocoagulation for proliferative sickle cell retinopathy has shown that photocoagulation is effective in preventing vitreous hemorrhage and visual loss from vitreous hemorrhage. In addition, a reduction of visual loss from all causes in photocoagulated eyes approaches statistical significance. Analysis of control eyes shows that there are three independent risk factors for the occurrence of vitreous hemorrhage: (1) the presence of the SC genotype, (2) the presence of vitreous blood at the initial evaluation and, (3) the presence of greater than 60 degrees of perfused neovascularization.

Anemia, Sickle Cell↗
PubMed1983

A randomized clinical trial of feeder vessel photocoagulation of proliferative sickle cell retinopathy. I. Preliminary results.

A randomized prospective clinical trial of feeder vessel photocoagulation for proliferative sickle cell retinopathy was performed. In Chicago there were 34 argon laser-treated eyes and 30 control eyes. In Kingston there were 53 xenon arc treated eyes and 50 control eyes. Prolonged loss of visual acuity was rare in both photocoagulated and control eyes. Argon laser and xenon arc feeder vessel photocoagulation reduced the incidence of vitreous hemorrhage and visual loss from vitreous hemorrhage. However, photocoagulation was associated with an increased risk of choroidal neovascularization (xenon arc greater than argon laser) and retinal detachment (argon laser), although visual loss from these complications has not been seen in these patients so far.

Adult↗
PubMed1981

Salmon-patch hemorrhages after central retinal artery occlusion in sickle cell disease.

In two patients with sickle cell disease (one hemoglobin SC and one hemoglobin SS), central retinal artery occlusions developed. In one case, the occlusion followed a retrobulbar injection of lidocaine hydrochloride. Although the central retinal artery reperfused in each patient, many secondary peripheral retinal arteriolar occlusions remained. During the subsequent days, multiple salmon-patch hemorrhages developed in the distribution of these occluded arterioles. In one patient, the salmon-patch hemorrhages evolved into atrophic schisis cavities. These unusual cases allowed us to document the origin of salmon-patch hemorrhages after peripheral retinal arteriolar occlusions. The development of the hemorrhages was a delayed phenomenon that occurred hours to days after the initial vascular occlusion. Reperfusion of the damaged ischemic vessels with a blowout of the wall of the vessels seems the most likely explanation for this phenomenon.

Adult↗
PubMed1979

General anaesthesia in sickle-cell disease.

General anaesthesia was administered on 284 occasions to 200 patients with sickle-cell disease at one hospital during July 1958 to June 1978. No intraoperative but six postoperative deaths occurred. The management of anaesthesia may have contributed to two of the postoperative deaths. Clinically uneventful anaesthesia did not appear to provoke severe sickling crises or to be responsible for mortality, but a contribution to postoperative morbidity could not be excluded. A simple, careful anaesthetic technique and selective but not routine blood transfusion appears to be associated with minimal anaesthetic morbidity and mortality in patients with sickle-cell disease.

Adolescent↗