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Biomedical subjects

G Ross

Publications and source records attributed to G Ross.

At least 145 records · Page 8Linked to original sources

Social competence and behavior problems in premature children at school age.

Social competence and behavior problems of 87 children born weighing less than 1501 g were measured using the Child Behavior Checklist when the children were 7 to 8 years old. Both premature boys and girls had significantly lower Social Competence scores than the normative samples of their respective sexes. Only premature boys had significantly higher Behavior Problems scores, with significantly higher scores on behaviors associated with conduct disorders. Premature children in each of three social class groups had significantly lower Social Competence scores and higher Behavior Problems scores than normative children. Furthermore, there was an interaction between prematurity and social class on Behavior Problems scores, with the greatest discrepancy in scores between premature and normative children in the lower-class group. Relative to other predictors, IQ score best explained Social Competence scores and family stability best explained Behavior Problems scores in the premature sample.

Child↗

Routine excretory urography in follow-up of superficial transitional cell carcinoma of bladder.

To determine cost-effective guidelines for the follow-up of patients with superficial transitional cell carcinoma of the bladder (STCCAB), we reviewed clinical histories, pathology reports, and intravenous pyelography results in 84 patients with Stage Ta or T1 disease. In 4 patients (4.8%) subsequent upper tract tumors developed with an average interval from initial presentation to the development of upper tract disease of 5.4 years. Three of these patients were treated successfully. We recommend upper tract surveillance in this group of patients with intravenous pyelography at diagnosis and every twenty-four months thereafter, or selection of those patients who are at high risk for development of upper tract disease (i.e., ureteral-vesical reflux) with voiding cystourethrography one month following each resection of tumors near a ureteral orifice. Refluxing patients should then either undergo surgical repair of their reflux or yearly pyelography.

Carcinoma, Transitional Cell↗

Pre- and post-treatment distribution pattern of 123I-MIBG in patients with phaeochromocytomas and paragangliomas.

123I-metaiodobenzylguanidine (MIBG) localizes in adrenergic neurones. A comparison of % washout of MIBG, during two time intervals, from various organs was carried out in seven normal volunteers and 11 patients with phaeochromocytoma and/or paraganglioma pre- and post-treatment using MIBG. % washout of MIBG during the time intervals of 30 min to 4 h were as follows: heart, controls 26.1 +/- 3.8 v. patients 51.5 +/- 9.1, (p less than 0.001), lungs, controls 36.5 +/- 5.3 v. patients 47.3 +/- 5.8, (p less than 0.05), liver, controls 26.5 +/- 5.7 v. patients 53.4 +/- 12.0 (p less than 0.01). Following treatment the % washout of MIBG from these tissues between 30 min and 4 h were similar in both groups of subjects. This observation coincided with the normalization of plasma catecholamine levels in most of the treatment group. There was no significant difference between the treatment and control groups, in the % washout of MIBG from these tissues during the 4 h and 22 h time intervals either before or after treatment. We conclude that quantitative scintigraphy 30 min to 4 h after MIBG administration is a useful technique to evaluate the pathophysiological effects of high circulating catecholamines in patients with phaeochromocytomas and/or paragangliomas.

3-Iodobenzylguanidine↗

Neuromotor development of preterm and full-term infants.

The Neuromotor Behavioral Inventory (NBI), a 16-category measure of muscle tone, developmental motor abilities, quality of movement, neurological reflexes and reactions, and neuromotor outcome was used with 38 infants divided into three groups: healthy preterm (HPT), sick preterm (SPT), and healthy full-term (HFT) infants. Infants were tested at five time points: 40 weeks postconception (newborn) and 3, 6, 9 and 12 months of age post-term. The intent of the study was two-fold: to determine whether there are developmental differences among the groups of infants and whether the differences persist during the first year of life. Results indicate that HFT and HPT infants score higher than SPT infants in the neuromotor categories of: muscle tone, upper extremity development, head control, and neuromotor outcome rating. HFT infants scored higher than both preterm groups in: trunk rotation, reaction to movement, visual and auditory attention, and fixing. Differences persisted among the groups during the first year of life in the following: the developmental motor ability of trunk rotation, fixing, adaptability, and the neuromotor outcome rating. It appears that neonatal health status is a contributing factor to infant neuromotor development, particularly in the quality of movement reactions.

Humans↗

Successful transplantation of blood group A2 kidneys into non-A recipients.

The ABO subgroup A2 has been reported to be less reactive with the anti-A1 antibody naturally occurring in the serum of group O and B recipients and to occur in approximately 20% of group A individuals. Between March 1986 and February 1987, the Midwest Organ Bank (MOB) in Kansas City, screened all group A renal donors for the A2 subgroup. A total of 190 cadaverdonor kidneys were retrieved during this time, of which 68 were subgroup A1 and 16 were subgroup A2 (incidence of A2 = 19% of As and 8.5% of all donors). Of the subgroup A2 kidneys, 13 were transplanted into 9 group O and 4 group B recipients. One group O recipient received an HLA-identical A2 living-related graft. Recipients were not preselected or modified by splenectomy, plasmapheresis, or other means, and were treated with cyclosporine, steroids--and, in most cases, azathioprine, after transplantation. There was one hyperacute rejection and there were 5 acute cellular rejection episodes, 3 of which were reversed. One additional patient died at 2.5 months with a functioning graft. Including the successful living-related graft, 10 of 14 patients (71%) have functioning grafts, with a follow-up of 5 to 14 months, and a mean creatinine of 1.7 mg/dl. We find that the A2 subgroup represents a small but important minority of A donors, and that transplantation into non-A recipients can generally, but not universally, be safely accomplished. We recommend the screening of A donors for the A2 subgroup in both the cadaver-donor and living-related groups, and suggest that the utilization of A2 donors in non-A patients may contribute to the transplantation of group O and highly sensitized patients--and, in some cases, improve the degree of HLA matching.

ABO Blood-Group System↗

Randomized clinical trial of testosterone replacement therapy in hypogonadal men.

We have compared the pharmacokinetics and pharmacodynamics of the three commonly used testosterone formulations in a prospective, randomized cross-over clinical trial. Plasma free and total testosterone and their ratio (proportion of unbound testosterone), sex hormone-binding globulin (SHBG), oestradiol, LH and FSH were measured in 15 hypogonadal men (nine hyper- and six hypogonadotrophic) who underwent, in a randomized sequence, three treatment periods each separated by an intervening washout period. The treatments were: (i) intramuscular injection of 250 mg mixed testosterone esters at 2-weekly intervals, (ii) oral testosterone undecanoate 120 mg bd, and (iii) subcutaneous testosterone pellets (6 x 100 mg). Pellet implantation gave the most prolonged effect with free and total testosterone levels being elevated for up to 4 months. This was accompanied by prompt and sustained suppression of plasma LH and FSH, an increase in plasma levels of oestradiol but no change in SHBG levels. In contrast, intramuscular injections induced marked but reproducible week-to-week fluctuations in free and total testosterone, which resulted in a small decrease in plasma SHBG levels, less marked suppression of LH and FSH and a smaller increase in plasma levels of oestradiol. Oral testosterone undecanoate produced the most variable plasma levels of free and total testosterone with a peak in the first treatment week and a fall thereafter and, despite maintenance of testosterone levels within the physiological range, there was no significant suppression of plasma levels of LH and FSH, and oestradiol levels were unchanged but levels of SHBG and total cholesterol were decreased. Free testosterone levels were increased disproportionately during testosterone treatment as the proportion of unbound testosterone was increased by all three treatments. All three testosterone preparations lowered plasma levels of urea and all were without biochemical or haematological toxicity. Reported sexual function was better maintained and side-effects were fewer with parenteral compared with oral treatments. The marked decrease in SHBG and cholesterol levels during oral testosterone undecanoate, when compared with parenteral treatments, occurred despite lesser androgenic effects (suppression of gonadotrophin levels and reported sexual function), which suggests that the liver is exposed to excessive androgenic load via the portal vein during oral treatment with testosterone esters. It is concluded that testosterone pellets give the closest approximation to zero-order (steady-state) delivery conditions for up to 4 months after a single insertion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

Modulation of the actions of tyrosine by alpha 2-adrenoceptor blockade.

1. Eight normal subjects were given, in double-blind, random order L-tyrosine 50, 250 and 500 mg kg-1 and placebo orally. Plasma tyrosine concentrations rose in a dose-dependent manner, without affecting the concentrations of the other large neutral amino acids. Tyrosine stimulated the secretion of prolactin and thyrotrophin (TSH) but had no effect on the plasma concentrations of adrenocorticotrophic hormone (ACTH), cortisol, growth hormone or the gonadotrophins. 2. The lack of a stimulant effect of tyrosine on ACTH secretion was presumed to be due to activation of one of the negative feedback mechanisms that control the rate of synthesis and release of the catecholamines, and this hypothesis was tested by examining the effects of the alpha 2-adrenoceptor antagonist idazoxan on the actions of tyrosine. 3. Seven normal males were given on 6 separate occasions tyrosine 250 and 500 mg kg-1 and placebo orally following pretreatment with saline and idazoxan (0.1 mg kg-1 i.v.). Following pretreatment with idazoxan, tyrosine stimulated the secretion of ACTH and noradrenaline in a dose-dependent manner, although neither tyrosine nor idazoxan on their own had any effect on the secretion of either substance. 4. The lack of effect of tyrosine when given on its own appears to be due, to partly, to activation of alpha 2-adrenoceptors, which inhibit the release of noradrenaline. Idazoxan caused a small increase in systolic blood pressure, both when given on its own and in combination with tyrosine. Neither tyrosine nor idazoxan had any significant effect on the state of behavioural arousal, as measured by visual analogue scales, or on the secretion of growth hormone or the gonadotrophins.

Adrenergic alpha-Antagonists↗

Variation in the lymphocyte transformation assay. Slope analysis of cell dose-response curves.

Blood samples from a single sheep were cultured at a number of different cell concentrations and stimulated with three lymphocyte mitogens, phytohaemagglutinin, concanavalin A and pokeweed mitogen. The response to stimulation, measured as log thymidine uptake (log cpm) was found to be a linear function of log cell concentration (log cell dose). Samples taken on different dates, varied significantly in the gradients of the log cpm: log cell dose plots. These alterations of gradient constituted the major source of variation of cpm in cultures at optimum cell concentration. It is concluded that the optimal mitotic response of lymphocyte cultures is determined more by the relative proportions of interactive cell types in the response than by the frequency of responder units. Also this proportion is subject to wide, spontaneous variation in the normal animal.

Animals↗

Observations on the function of normal adrenomedullary tissue in patients with phaeochromocytomas and other paragangliomas.

123I-MIBG is a norepinephrine analogue used for imaging phaeochromocytomas and other paragangliomas. In this study 7 normal volunteers and 31 subjects with high or borderline high plasma catecholamine and urinary metanephrine and VMA levels were investigated. In the normals the uptake by the adrenal medulla was in the range of 0.01%-0.21% of the injected dose at 22 h. In 22 subjects there was no evidence for any paraganglioma, with the uptake by the adrenal medulla in the range of 0.01%-0.22% of the injected dose at 22 h. In nine patients there was evidence of a paraganglioma on imaging which was confirmed on surgery. The uptake by the tumours was in the order of 0.001%-0.14% of the injected dose per gram of tumour tissue. In all nine cases the non-tumorous adrenal medulla could be visualized; the uptake in the adrenals was in the range of 0.01%-0.21% of the injected dose. This study shows that in the presence of elevated plasma catecholamines of tumour origin the unaffected adrenal medullary tissue retains the capacity for 123I-MIBG uptake. In the two cases also studied by adrenal venous sampling, catecholamine release was also within the normal range.

3-Iodobenzylguanidine↗

Relaxation induced by KCl, NaCl and sucrose in rabbit coronary arteries.

Contractions induced in isolated ring segments of rabbit coronary arteries by 2-(2-aminoethyl)-pyridine (AEP) were transiently relaxed when KCl, NaCl or sucrose were added to the bathing solution without osmotic correction. When these solutes were added with osmolarity changes minimized by reducing the concentration of another constituent of the medium the relaxations were reduced or abolished. AEP contraction was associated with depolarization and solute-induced relaxation with a lessening of the depolarization. Ouabain depolarized the vessel and diminished both the relaxation and repolarization induced by hyperosmolar addition of NaCl and sucrose to AEP-contracted segments. Sucrose and NaCl also relaxed potassium-induced contractions and their effect was greater at [K]o 25 mM than at [K]o 60 mM. Hyperosmolar relaxation still occurred but was significantly smaller in vessels subjected to prolonged sodium pump inhibition produced by cold storage followed by re-warming in K-free or ouabain-containing solution. It is concluded that hyperosmolar relaxation is mainly due to hyperpolarization and is influenced by the level of membrane potential. The inhibition of hyperosmolar relaxation by ouabain may be due to its depolarizing action.

Animals↗

Hand preference of four-year-old children: its relationship to premature birth and neurodevelopmental outcome.

Information was obtained at age four years on the hand preference of 98 children who had been born prematurely with a very low birthweight and of 54 children born at term with no birth complications. Data were also collected on the hand preference of their parents. The preterm children had been assessed at age three years for IQ, expressive language, speech articulation and neurological status. A significantly lower proportion of preterm than of term children used their right hand for unimanual activities. Furthermore, those preterm children who were not right-handed were significantly more likely to have lower IQs, expressive language delays and articulation problems. Among preterm children with IQs greater than or equal to 85, language and speech problems were no more likely to occur in those who preferred the left hand or who used both hands than in those who preferred the right. The findings of this study support the theory that birth complications lead to cerebral insult which may alter hand preference, and at the same time affect mental and motor development.

Child Development↗

Effect of adrenaline on basal and ovine corticotrophin-releasing factor-stimulated ACTH secretion in man.

Six normal male subjects were given, in single blind random order on six separate occasions, i.v. bolus doses of synthetic ovine corticotrophin-releasing factor-41 (oCRF-41; 25 and 50 micrograms) with and without adrenaline (3 micrograms/min) i.v. for 150 min, the adrenaline infusions alone and saline placebo. The adrenaline infusions resulted in plasma adrenaline concentrations of 4.33 +/- 0.82 (S.E.M.) nmol/l and were associated with an increase in blood glucose, heart rate and systolic blood pressure and a reduction of diastolic blood pressure. Despite these evident biological effects at several sites, there was no stimulation of plasma ACTH or cortisol by adrenaline in comparison with the effect of saline, and no enhancement of the stimulatory effect of either dose of oCRF-41 on ACTH or cortisol secretion. The ACTH response to 50 micrograms oCRF-41 was greater than that to 25 micrograms, indicating that the 25 micrograms dose of oCRF-41 was submaximal and capable of further enhancement. As the plasma adrenaline concentrations during the adrenaline infusions reached the upper limit of the physiological range of plasma adrenaline in man, yet failed to enhance the ACTH or cortisol responses to a submaximal dose of oCRF-41, we conclude that circulating adrenaline neither exerts a direct stimulatory effect on pituitary corticotrophs nor enhances the effect of CRF under physiological circumstances. The adrenaline infusions attenuated the ACTH and cortisol responses to oCRF-41 and were associated with a transient reduction of basal concentrations of both hormones.

Adrenocorticotropic Hormone↗

Temperament of preterm infants: its relationship to perinatal factors and one-year outcome.

We studied preterm infants to determine whether they have more difficult temperaments than term infants, and whether temperament is related to perinatal factors and to later performance on infants tests. Parents of 98 preterm and 89 full-term infants completed the Toddler Temperament Scale (TTS) when their children were 12 months post-term. Ninety-five of the 98 preterm infants also received the Bayley Scales of infant Development and were diagnosed as to the presence and severity of cerebral palsy (CP) at one year post-term. Preterm and full-term infants did not differ significantly on overall temperament type or on any of nine temperament dimensions. Degree of respiratory distress was correlated significantly with premature infants' receiving scores significantly different from normal on some temperament dimensions. Poorer performance on the Bayley Mental Scales was significantly associated with temperament characteristics of lower adaptability, lower persistence, and more withdrawal from new stimulation.

Female↗

Uptake of iodine-123 MIBG by pheochromocytomas, paragangliomas, and neuroblastomas: a histopathological comparison.

The percentage uptake of [123I]metaiodobenzylguanidine (MIBG) by tumors of the paraganglion system is compared with the number of neurosecretory granules (assessed by both light and electron microscopy) in the subsequently resected tumors in six patients. Iodine-123 MIBG was injected intravenously; the tumor uptake of [123I]MIBG varied between 0.001% and 0.14% of the injected dose per gram of tumor tissue at 22 hr. The number of neurosecretory granules in tissue sections was scored on a scale of I-III. A direct proportional correlation was found between the percentage uptake of [123I]MIBG by the tumor and the number of neurosecretory granules in the tissue sections but not with plasma or urinary catecholamines. This technique for imaging reflects the storage status of the tumor better than plasma and urinary catecholamine measurements.

3-Iodobenzylguanidine↗

Quantitation of iodine-123 MIBG uptake by normal adrenal medulla in hypertensive patients.

Eighteen hypertensive patients with a clinical suspicion of pheochromocytoma and raised or borderline raised plasma catecholamine and urinary vanillyl mandelic acid (VMA) levels were studied by scintigraphy using 123I-labeled metaiodobenzylguanidine (MIBG). None of these patients had any scintigraphic evidence of pheochromocytoma at the time of study or on subsequent clinical follow-up. A quantitative approach was taken to calculate the adrenal medullary uptake of [123I]MIBG in these patients. Three different methods of quantitation were evaluated using data acquired from an anthropomorphic phantom and analysed by three independent observers. In the patient studies 34 out of 35 adrenal medullas were visualized with uptake in the range of 0.01-0.22% of the administered dose 22 hr postinjection which was calculated using the preferred quantitation method. This is an appropriate control group range for comparison with patients who have proven norepinephrine and epinephrine secreting tumors. A quantitative approach to [123I]MIBG imaging provides an important tool for studying adrenomedullary pathophysiology.

3-Iodobenzylguanidine↗