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Biomedical subjects

R A Low

Publications and source records attributed to R A Low.

At least 19 recordsLinked to original sources
PubMed1998

Parathyroidectomy via bilateral cervical exploration: a retrospective review of 866 cases.

INTRODUCTION: Parathyroidectomy via cervical exploration is an effective primary-modality treatment for hyperparathyroidism, with cure rates of greater than 95%. We retrospectively reviewed 866 consecutive parathyroidectomies performed by a single surgeon between 1960 and 1997. We attempted to describe the polymorphic variation in multiglandular disease, the anatomic locations of pathologic glands, and the operative strategy and techniques which we believed were important to minimizing morbidity and maximizing curative success. METHODS: The cases of 329 males and 537 females (age, 1-88 years) were reviewed. There were 766 operations performed: primary hyperparathyroidism (713), tertiary hyperparathyroidism (100), reoperations (53). The strategy for primary exploration includes a bilateral neck exploration, early recurrent laryngeal nerve skeletonization, and identification of at least four glands. RESULTS: Normocalcemia was achieved in 98.2% of cases after initial cervical exploration. Persistent hypercalcemia occurred in 7 patients (<1%). Nine patients (1%) suffered persistent postoperative hypocalcemia. Unilateral recurrent laryngeal nerve injury occurred in two patients (<1%). Other perioperative complications included: reoperation for hematoma, repaired carotid artery injury, unexplained dysphagia, pneumothorax, deep venous thrombosis, and aspiration pneumonia. There were two mortalities (<1%) attributable to severe, comorbid disease. Ectopic glands were found in 120 cases. The frequency of glands at these sites were as follows: mediastinal (4.9%), intrathymic (8.4%), intrathyroid (6.7%), and retroesophageal/retrotracheal (3.5%). Thyroid resections provided diagnosis of concomitant thyroid carcinoma in 8.0% of resected patients. The pathology of patients with primary hyperparathyroidism (PHPT) consisted of single adenomas (77.2%), hyperplasia (21.0%), normal glands (1%), double adenomas (<1%), and parathyroid carcinoma (<1%). The distribution of adenomas was as follows: left upper, 25.3%; left lower, 27.3%; right upper, 26.8%; right lower, 20.6%. Hyperplastic glands were found in ectopic positions as follows: intrathymic (7.5%), intrathyroid (11.3%), mediastinal (2.5%), and retroesophageal/retrotracheal (0%). The average volume difference between the largest and smallest hyperplastic gland of each case was 1.80 + 4.40 cm3. Reoperations were performed upon 53 referred patients and 7 patients after failed exploration. Normocalcemia was attained in 98.3% of cases. Glandular pathology was identified in the previous operative field in 52 patients (86.7%). Adenomas were identified in 56.0% (n = 23) and hyperplasia in 39.0% (n = 16). CONCLUSIONS: In our series, we were able to attain normocalcemia in 98.2% of cases after initial cervical exploration. We believe that identification of four glands, an exhaustive search of ectopic sites, bilateral exploration, and liberal use of biopsy and intraoperative frozen section were essential to curative success. The pathologist should identify parathyroid tissue in the specimen and differentiate the "abnormal" from "normal" gland. Morphologic criteria alone cannot be used because of polymorphic variation in hyperplasia in which pathologic glands may appear normal. Early identification of the recurrent laryngeal nerve allows for a safer neck exploration by alerting the surgeon to the location and course of the nerve. A bilateral approach does not contribute increased morbidity from recurrent laryngeal nerve injury.

Adolescent↗
PubMed1995

Neutrophil modulation results in improved pulmonary function after 12 and 24 hours of preservation.

Neutrophils are important mediators of reperfusion injury, and suppression of neutrophil function or numbers can reduce reperfusion injury and improve long-term organ preservation in transplantation. NPC 15669, a leumedin, is a novel compound that prevents recruitment of neutrophils at inflammatory foci by inhibiting CD11b/CD18 adhesion molecule expression. NPC 15669 was used to inhibit neutrophil adhesion during reperfusion of isolated rabbit lungs after 12 and 24 hours of cold storage. Lungs (New Zealand White male rabbits, 2 to 3 kg) were flushed with 4 degrees C Euro-Collins (EC) solution, harvested en bloc, stored under various study conditions, and reperfused for 3 hours with fresh whole blood at 37 degrees C in an isolated perfusion system at constant flow and an inspired oxygen fraction of 1. Four groups (n = 6 each) were studied. Group I underwent immediate whole blood reperfusion. Group II were stored for 12 hours in 4 degrees C EC solution before reperfusion. Group III were stored for 12 hours in 4 degrees C EC solution and reperfused with whole blood containing NPC 15669 (10 mg/kg whole body weight). Group IV were stored for 24 hours in 4 degrees C EC solution and reperfused with whole blood containing NPC 15669 (10 mg/kg). Pulmonary artery and peak airway pressures were significantly lower and compliance higher in groups III and IV lungs after 3 hours of reperfusion (p < 0.05) compared with group I. Group I and III lungs had significantly less edema than group II (p < 0.05). The arterial partial pressure of oxygen was similar in all stored groups (II to IV).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Obstetric aspects of the use in pregnancy-associated hypertension of the beta-adrenoceptor antagonist atenolol.

The obstetric implications of the use of the beta-adrenoceptor antagonist atenolol have been evaluated in a prospective, randomized, double-blind, and placebo-controlled study involving 120 women with pregnancy-associated hypertension. The clinical interpretation of antenatal and intrapartum cardiotocographs was uninfluenced by atenolol. Human placental lactogen concentration fell in the atenolol group, but this was not an indicator of subsequent fetal distress. Other obstetric indices, such as urinary estriol excretion, were the same in both groups. Spontaneous premature labor occurred in five women receiving placebo but in none who received atenolol. Together with previously reported findings on pregnancy outcome, our study leads us to conclude that beta-blockers such as atenolol can appropriately be used in the management of hypertension during pregnancy.

Atenolol↗
PubMed1984

Danazol and prolactin status in patients with endometriosis.

A group of 55 women with endometriosis was studied before and during danazol therapy. An unexpectedly high proportion (36%) had a raised serum prolactin level before treatment which was reduced after 50 days of danazol (before treatment 783 +/- 333 mU/l; on danazol 243 +/- 113 mU/l, P less than 0.001). In contrast patients with normal serum prolactin levels showed no significant drop on danazol therapy. In all patients serum oestradiol was significantly reduced during treatment (before treatment 449 +/- 188 pmol/l; on danazol 207 +/- 117 pmol/l, P less than 0.001). In one patient with hyperprolactinaemia danazol reduced both basal and stimulated prolactin levels, whereas in 5 women with normal prolactin levels we could detect no gross alteration in metoclopramide or TRH stimulated prolactin levels associated with danazol therapy. The possibility that normalisation of raised prolactin levels may be secondary to reduced oestrogens and that patients with endometriosis have an increased sensitivity to oestrogen-induced prolactin secretion is discussed.

Danazol↗
PubMed1983

Placebo-controlled trial of atenolol in treatment of pregnancy-associated hypertension.

Atenolol was compared with placebo in a randomised and double-blind prospective study of 120 women with mild to moderate pregnancy-associated hypertension who were also initially managed conventionally by bed rest. Atenolol given once daily significantly reduced blood-pressure, prevented proteinuria, and reduced the number of hospital admissions. Loss of blood-pressure control leading to withdrawal from the study was commoner among the placebo group, whose babies had a high morbidity. Respiratory distress syndrome occurred only in the placebo group. Intrauterine growth retardation, neonatal hypoglycaemia, and hyperbilirubinaemia occurred with the same frequency in the two groups. Neonatal bradycardia was more common after atenolol but the systolic blood-pressure of the babies was the same in both groups. There was no difference between the groups in maternal symptoms which could have been attributed to beta-blocker therapy. Thus atenolol is more effective than conventional obstetric management in this form of hypertension and does not adversely affect mother or baby.

Adult↗
PubMed1983

Clinical pharmacological studies with prazosin during pregnancy complicated by hypertension.

The disposition and effect of orally administered prazosin have been studied in eight women with hypertension which was uncontrolled by beta-adrenoceptor blockade during the last trimester of pregnancy. Results were compared with healthy men of similar age. The median time to peak concentration was 165 min during pregnancy and 120 min in the men (P less than 0.04). Area under the concentration vs time curve was 3914 ng l-1 min in pregnancy and 2439 ng l-1 min in the men (P less than 0.06). Mean elimination half-life was 171 min in the pregnant women and 130 min in the men (P less than 0.01). Blood pressure was lowered by prazosin in both supine and standing positions. Blood pressure control remained satisfactory in six of the eight women and the median prolongation of pregnancy was 22 days. Neonatal outcome was satisfactory and all babies are developing normally. We conclude that prazosin is more slowly, but apparently more completely, absorbed during pregnancy and that its half-life is slightly prolonged. Prazosin appears to be both effective and safe when used during the last trimester to control blood pressure.

Adolescent↗
PubMed1983

Atenolol elimination in the neonate.

The elimination of the cardioselective beta-adrenoceptor antagonist atenolol has been studied in 35 neonates by measuring drug concentration in cord blood and in blood obtained at 24 h by heel stab. Elimination rate was assessed by calculating the slopes of lines joining these two concentration points. The slopes had a mean of 0.043 h-1 (equivalent to a half-life of 16 h) and were normally distributed with 95% of values being in the range 0.02-0.066. There was no relationship between slope and neonatal weight or skinfold thickness, but most babies were at term and the range of these indices was narrow. Babies who developed a bradycardia had cord atenolol concentrations and slopes which did not differ significantly from those in babies without bradycardia. We conclude that atenolol elimination in the neonate is reduced when compared to adults. This prolonged elimination is consistent with the physiological characteristics of this age group and with previous observations on drugs eliminated by renal excretion.

Atenolol↗
PubMed1982

Atenolol in the treatment of essential hypertension during pregnancy.

Atenolol has been studied prospectively in the management of ten patients with essential hypertension during pregnancy. Median supine BP fell significantly from 156/98 mmHg before treatment to 128/82 mmHg at term. Atenolol did not suppress cardiotocographic signs of foetal distress. Although there was one intrauterine death, the remaining nine babies had a median Apgar score at birth of 9 and a median weight which was 82% of the gestational mean. There were no cases of neonatal bradycardia or respiratory depression and the only case of hypoglycaemia was in a dysmature baby. These findings justify a formal study of beta-adrenoceptor blocker therapy in hypertensive diseases of pregnancy.

Atenolol↗
PubMed1979

The contribution of drinking water lead to maternal blood lead concentrations.

The association between domestic water lead concentrations and blood lead concentrations has been examined in 232 mothers at delivery. The blood lead was found to vary significantly with the cube root of the water lead. This association was stronger for first flush water lead rather than for running water lead. This study emphasises the danger to mothers and to their children of environmental lead over-exposure in areas of soft acid plumbosolvent water.

Adolescent↗
PubMed1979

Prenatal and postnatal maternal leucocyte ascorbic acid concentrations.

Leucocyte ascorbic acid was measured in 79 pregnant women in the 34th to 38th week of gestation and on the first, and third or fifth days post partum. No differences were found for time of year or age of the subjects. There was a significantly lower vitamin C status in social classes IV and V. The leucocyte ascorbic acid concentration fell significantly on the first day post partum and rose again to initial values by the fifth day. In late pregnancy 40 per cent of all subjects had leucocyte ascorbic acid concentrations less than the lower limit of normal (100 nmol/10(8) leucocytes). This rose to 75 per cent on the first day post partum.

Adolescent↗
PubMed1977

Pregnancy and the acute porphyrias.

An analysis is presented of the obstetric histories of 50 women with acute porphyria, comprising 39 with acute intermittent porphyria, 3 with variegate porphyria and 8 with hereditary coporporphyria. Fifty-four per cent of the women with acute intermittent porphyria had an acute attack of porphyria in pregnancy and/or the puerperium. Only one maternal death was recorded. One patient with variegate prophyria and two with hereditary coproporphyria had an attack related to pregnancy. The total fetal wastage was 13 per cent. The babies born to mothers with acute intermittent porphyria, who experienced an acute attack during pregnancy, were smaller than those in which no such attack occurred (P less than 0.001). In 13 non-porphyric primigravidae there was a rise in urinary excretion of delta-aminolaevulinic acid, porphobilinogen and coproporphyrin up to the 28th week of gestation. It is probable that pregnancy has some deleterious effects in acute prophyria but the prognosis of the porphyric pregnancy is much better than the literature suggests.

Acute Disease↗