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Biomedical subjects

L Gordon

Publications and source records attributed to L Gordon.

At least 145 records · Page 8Linked to original sources
PubMed1990

Utility of Tc-99m DTPA aerosol inhalation scans following perfusion lung scans in the diagnosis of pulmonary embolism.

The authors report their experience with the use of Tc-99m DTPA aerosol following a perfusion lung scan. The study includes 422 consecutive patients with suspected pulmonary embolism. The final diagnosis was determined by (a) clinical follow-up for 2 months or more, (b) pulmonary angiography, or (c) autopsy. There were 79 patients (19%) who had a normal or near-normal perfusion study and in whom no aerosol study was required. Interpretation groups were classified and divided as follows: Normal or low probability 281 (66.5%) High probability 75 (18.0%) Intermediate 60 (14.0%) Technically inadequate 6 (1.5%) There was autopsy or angiographic confirmation of 72 patient studies with confirmation of the scan diagnosis in 29 of 31 classified as normal or low probability and 24 of 25 classified as high probability. The background perfusion albumin activity was not computer-subtracted from the combined aerosol-perfusion image. Technical improvements included the use of eight standard views for both the perfusion and the subsequent aerosol scan, and the use of 75 mCi (2,775 MBq) of Tc-99m DTPA in the radioaerosol nebulizer. This allowed for easy accumulation of more than three times the count rate in a posterior aerosol image when compared with the previous posterior perfusion image. The authors' experience shows that the perfusion lung scan followed by this radioaerosol technique is a reliable means to evaluate suspected pulmonary embolism.

Administration, Inhalation↗
PubMed1990

A single gel for determining genetic variants of equine erythrocyte carbonic anhydrase (CA) and catalase (Cat).

We describe a method for agarose IEF under acid conditions in which a single gel can be used to diagnose from equine red cell lysates genetic variants for carbonic anhydrase (CA) and catalase (Cat). Family and population data for 4801 horses of 27 breeds and seven trap sites of Great Basin feral horses are presented to support the presence of a sixth CA allele, CAE, which has been recognized previously, but not described by published data. Allelic frequencies for the two systems suggest it may be appropriate to use this gel for parentage verification programmes or to obtain population data for studies of the genus Equus.

Alleles↗
PubMed1990

Health, growth and sexual development of teenagers exposed in utero to medroxyprogesterone acetate.

General health, growth and sexual development were evaluated in 74 teenage boys and 98 girls who had been exposed to medroxyprogesterone acetate (MPA) in utero, and 385 boys and 448 girls not exposed. In this 17-year prospective study, the ascertainment of the end points was 'double blind' in that neither the interviewer nor the subject was aware of our interest in MPA. On average, girls exposed to MPA reported reaching the menarche 4 months earlier than the comparison group. This difference disappeared, however, in a multiple regression analysis taking into account social class, the mother's age at menarche and height of the girl's mother and father. Boys exposed to MPA reported their growth spurt to have occurred an average of 6 months earlier and voices to have broken 5 months earlier than unexposed boys. Again, the differences between them and the comparison group disappeared after controlling for confounding variables. There were no significant differences between the MPA-exposed and comparison groups in a wide variety of indices of health reported by the teenagers' mothers. These findings are consistent with the hypothesis that intrauterine exposure to MPA, in the doses used for pregnancy maintenance or for contraception, poses no threat to the long-term health and development of the progeny.

Adolescent↗
PubMed1990

Immunohistochemical demonstration of human cardiac innervation before and after transplantation.

Knowledge about the distribution and origins of peptide-containing nerves in the innervated and transplanted heart is lacking. Immunohistochemical and histochemical techniques were used to visualize human cardiac innervation before and after transplantation. In the recipient heart cardiac nerve fibers and fascicles displayed immunoreactivity for general neural (protein gene product 9.5 and synaptophysin) and Schwann cell markers (S-100). A major proportion of cardiac nerves displayed neuropeptide tyrosine and tyrosine hydroxylase immunofluorescence staining. Subpopulations of nerves contained somatostatin, vasoactive intestinal polypeptide, calcitonin gene-related peptide, substance P- or neurokinin-like immunoreactivity, and acetylcholinesterase activity. Tissues from cardiac allografts (5 weeks to 63 months after transplantation) contained nerves and ganglion cells that were acetylcholinesterase positive and immunoreactive for the general neural markers. These nerves were less numerous than in recipient hearts and rarely displayed neuropeptide immunostaining. Atrial natriuretic peptide immunoreactivity was localized to myocardial cells in transplanted hearts as well as explanted recipient and postmortem hearts. While most human cardiac allografts remain functionally extrinsically denervated, they appear to contain viable intrinsic nerves, and myocardial cells retain the capacity to produce atrial natriuretic peptide.

Adolescent↗
PubMed1990

Myocardial localization and isoforms of neural cell adhesion molecule (N-CAM) in the developing and transplanted human heart.

Neural cell adhesion molecule (N-CAM) has been implicated in cellular interactions involved in cardiac morphogenesis and innervation. Immunohistochemical techniques and Western blot analysis were used to determine the localization and isoforms of N-CAM in the developing and extrinsically denervated human heart. Myocardial and conducting cells in the fetal heart (7-24 wk gestation) exhibited sarcolemmal immunoreactivity, the major desialo N-CAM isoforms being 150, 145, 120, 115, and 110 kD. N-CAM expression appeared to be downregulated in the myocardium during adult life, with relatively little sarcolemmal immunoreactivity being detected in normal donor tissues. In contrast to the temporal changes observed in the myocardium, both the developing and mature cardiac innervation displayed N-CAM immunofluorescence staining, localized to neuronal cell bodies, nerve fascicles and fibres. Extrinsically denervated cardiac allografts, obtained 2 d to 91 mo after transplantation, showed extensive sarcolemmal and intercalated disc immunostaining and expression of 125-, 120-, and 115-kD isoforms. Tissues from explanted recipient hearts and atrial appendage samples obtained during coronary bypass graft operations were also examined and displayed varying amounts of N-CAM immunoreactivity. We conclude that the expression of N-CAM immunoreactivity and isoforms in the human heart is developmentally regulated and may be modulated by factors such as cardiac innervation and myocardial hypertrophy.

Adult↗
PubMed1990

The Edinburgh-ORLAU prosthetic system to provide reciprocal locomotion in children and adults with complete transverse lower limb deficiency.

A novel prosthetic system to provide reciprocal locomotion in children and adults with complete transverse lower limb deficiency is described. This is based on the hip joints from the ORLAU ParaWalker, a system with a proven record of success in the orthotic management of paraplegic patients. The fitting of the prototype system to an eight year old girl is described. This experience shows that the orthotic principles of the ParaWalker, which provides reciprocal locomotion for the paraplegic, is equally applicable to the prosthetic situation. Developments are therefore continuing to improve the design and to enable further fittings.

Artificial Limbs↗
PubMed1990

Persistence of antibody and booster responses to reimmunization with Haemophilus influenzae type b polysaccharide and polysaccharide diphtheria toxoid conjugate vaccines in children initially immunized at 15 to 24 months of age.

To evaluate the persistence of antibody after Haemophilus influenzae type b polysaccharide vaccine (PRP) and H influenzae type b polysaccharide diphtheria toxoid conjugate vaccine (PRP-D), a group of 141 infants initially immunized between 15 and 24 months of age were studied 1 year later. One month after immunization with PRP, the man anti-PRP antibody level was 0.27 microgram/mL and 1 year later was 0.29 microgram/mL (not significant). In the group immunized with PRP-D, the levels were 1.34 micrograms/mL and 1.20 micrograms/mL (not significant), respectively. To evaluate immunogenicity and safety of a booster immunization 1 year after initial vaccination, subjects were randomly assigned to receive saline, PRP, or PRP-D. In addition, 73 age-matched previously unimmunized subjects were vaccinated with PRP or PRP-D. In all groups, adverse reactions were minor and resolved by 48 hours. Subjects receiving booster immunization with PRP or PRP-D had significantly greater antibody responses than children of the same age receiving their first dose of vaccine. The highest antibody levels were achieved in children initially immunized with PRP-D, regardless of whether the booster vaccine was PRP (112.8 micrograms/mL) or PRP-D (122.0 micrograms/mL) (not significant). Antibody levels after booster vaccine were significantly lower in those initially given PRP compared with those initially given PRP-D but significantly higher than in age-matched previously unimmunized control subjects (PRP booster 3.16 micrograms/mL vs control of 0.62 microgram/mL [P less than .05]; PRP-D booster 12.31 micrograms/mL vs control 2.31 micrograms/mL [P less than .01]).

Antibody Formation↗
PubMed1990

Cystic neoplasms of the pancreas.

Cystic neoplasms of the pancreas can be easily misdiagnosed and mistreated by the surgeon unfamiliar with the pathology, natural history, and operative strategy specific to these uncommon tumors. The authors have treated nine patients over a seven-year period involving four cystadenocarcinomas, two mucinous cystadenomas, two serous cystadenomas, and one solid and papillary epithelial tumor. Our experience illustrates the inaccuracies in both clinical and pathologic diagnosis. Suspected cystic neoplasms are optimally managed by resection. Their slow growth and late metastasis permits curative surgery after a previous drainage or bypass procedure. An aggressive surgical approach is therefore warranted, and multimodal treatment with radiation and chemotherapy may be clinically applicable to large, invasive cystadenocarcinomas.

Adult↗
PubMed1990

Postatelectatic ventilation-perfusion mismatch simulating a pulmonary embolus.

Ventilation-perfusion imaging was performed on a patient with chronic intermittent atelectasis of the right lung and revealed a mismatch simulating a pulmonary embolus in the right lung. A pulmonary arteriogram revealed no evidence of embolic disease; however, there was reduced capillary phase opacification of the right lung and increased pulmonary artery pressure. The findings are consistent with an isolated right pulmonary artery hypertension secondary to prolonged atelectasis causing an apparent mismatch on the ventilation-perfusion scan.

Adolescent↗
PubMed1989

Neural cell adhesion molecule (N-CAM) expression during cardiac development in the rat.

Neural cell adhesion molecule (N-CAM) expression was examined in the rat heart using immunohistochemical and immunochemical techniques. N-CAM immunoreactivity was displayed by myocardial cells from embryonic day E12 and by cardiac nerves when first identified at day E18. Myocardial immunostaining increased up until about postnatal day 1 and then declined rapidly thereafter whereas neural immunoreactivity persisted in the adult. N-CAM cardiac isoforms also exhibited developmental changes from the main embryonic moieties (105 and 145 kDa) to the principal postnatal (125 and 155 kDa) and adult isoforms (125 kDa). Cardiac N-CAM expression is therefore subject to temporal regulation and may modulate cellular interactions in the developing heart.

Animals↗
PubMed1989

Influence of body habitus and race on bone mineral density of the midradius, hip, and spine in aging women.

Osteoporosis and fractures of the hip are less common in black women and in obese white women than in nonobese white women. To determine the effects of race, age, and body weight on bone mineral density (BMD), BMD of the lumbar spine, trochanter, and femoral neck were determined by dual-photon absorptiometry in 131 nonobese white women and 34 nonobese black women, all of whom were within 30% of their ideal body weight, and in 24 obese white women and 27 obese black women, all of whom weighed more than 30% of their ideal body weight and were in the same age range as the nonobese women. All of them were 51 years of age or older, and most of them were postmenopausal. BMD of the midradius was measured by single-photon absorptiometry. Whereas body weight was significantly higher in the black as compared to the white women, the ages of the two groups were not different from each other. BMD declined with age and increased with body weight in both the black and white women at each of the four sites measured. After adjusting for age and weight by covariate analyses, black women had greater BMDs than white women at the midradius, lumbar spine, and femoral neck (p less than 0.001), but not at the trochanter (p = 0.18). The increases in BMD observed in the obese and black women in the present study are consistent with the previous findings that osteoporosis and fractures of the hip are less common in black and in obese white women than in nonobese white women.

Aged↗
PubMed1989

Neural cell adhesion molecule is expressed by smooth muscle cells during the development of the rat vascular system.

The presence and distribution of neural cell adhesion molecule (N-CAM) was examined by light and electron microscopical immunocytochemistry in the descending thoracic aorta, the superior mesenteric artery and mesenteric arteries from fetal and adult rats (embryonic day 15 to post-natal day 90). In embryonic and early post-natal rats, N-CAM immunoreactivity was localized in perivascular nerves, in the smooth muscle cell plasma membrane and basal lamina. In nerves, N-CAM-immunoreactive sites were found associated with both the axon and Schwann cell membranes. N-CAM immunoreactivity was also found associated with the surface of adventitial fibroblast-like cells and with collagen fibrils, in regions where these fibrils were in contact with smooth muscle cells. In mature vessels N-CAM immunoreactivity was found to be restricted to the perivascular innervation and the surface of fibroblast-like cells. These observations indicate that N-CAM is expressed transiently in rat vascular tissues during development and is localized not only on the surface of smooth muscle cells but also in association with extracellular matrix components.

Aging↗
PubMed1989

Tutorial on large deviations for the binomial distribution.

We present, in an easy to use form, the large deviation theory of the binomial distribution: how to approximate the probability of k or more successes in n independent trials, each with success probability p, when the specified fraction of successes, a identical to k/n, satisfies 0 less than p less than a less than 1.

Amino Acid Sequence↗
PubMed1989

The effects of muscle-building exercise on bone mineral density of the radius, spine, and hip in young men.

We previously demonstrated that muscle-building exercise is associated with increases in serum Gla-protein, serum 1,25(OH)2D, and urinary cyclic AMP. These studies were interpreted to mean that this form of exercise increases bone formation and modifies the vitamin D-endocrine system to provide more calcium for bone. The present investigation was carried out in normal young adult white men to determine the effects of exercise on bone mineral density at weight-bearing and nonweight-bearing sites. Twelve men who had regularly engaged in muscle-building exercises (use of weights, exercise machines, or both) for at least 1 year and 50 age-matched controls (aged 19-40 years) were studied. The body weights of the two groups were not different from each other (78 +/- 2 vs. 74 +/- 1 kg, NS). Bone mineral density (BMD) of the lumbar spine, trochanter, and femoral neck was measured by dual-photon absorptiometry, and BMD of the midradius was measured by single photon absorptiometry. It was found that muscle-building exercise was associated with increased BMD at the lumbar spine (1.35 +/- 0.03 vs. 1.22 +/- 0.02 g/cm2, P less than 0.01), trochanter (0.99 +/- 0.04 vs. 0.86 +/- 0.02 g/cm2, P less than 0.01), and femoral neck (1.18 +/- 0.03 vs. 1.02 +/- 0.02 g/cm2, P less than 0.001) but not at the midradius (0.77 +/- 0.02 vs. 0.77 +/- 0.01 g/cm2, NS). These studies provide additional evidence that muscle-building exercise is associated with increases in BMD at weight-bearing sites but not at nonweight-bearing sites.

Adult↗
PubMed1989

Left ventricular dysfunction in symptomatic mitral valve prolapse.

Idiopathic MVP is characterized by a late systolic click or murmur from myxomatous mitral valvular dysfunction. It may be complicated by atypical chest pain, ventricular arrhythmias, and ECG changes that can mimic the symptoms of coronary artery disease. We prospectively performed radionuclide cineangiograms before and after stress tests in MVP patients with chest pain compared with asymptomatic MVP patients and symptomatic normal control patients. In ten patients with MVP, chest pain, and normal coronary anatomy, the LVEF remained essentially unchanged (increase of -0.5 +/- 4 percent) after exercise. In ten patients with MVP and no chest pain and in nine with normal cardiovascular system and chest pain, the exercise LVEF increased by 11.5 +/- 2 percent (p less than 0.05) and 17.4 +/- 3 percent (p less than 0.005), respectively. The resting LVEF was significantly lower (p less than 0.02) in the symptomatic MVP patients (59 +/- 3 percent) than in the asymptomatic MVP (76 +/- 5 percent) or symptomatic normal patient control subjects (70 +/- 3 percent). Patients with MVP and chest pain had a lower resting LVEF and an abnormal left ventricular functional response to exercise compared with asymptomatic MVP patients or symptomatic normal subjects. Therefore, exercise radionuclide ventriculography may not adequately differentiate between chest pain due to MVP or coronary artery disease.

Cineangiography↗
PubMed1989

Revealing hidden competencies: a new method for studying language comprehension in children with motor impairments.

Pilot work on a new method to assess language comprehension in children with motor impairments was presented. The paradigm is based on the premise that children will prefer to watch a video event that matches a linguistic stimulus rather than an event that does not match the linguistic stimulus. Two experiments, one on noun comprehension and one on verb comprehension, were conducted on young children having cerebral palsy and other neurological pathology associated with motor deficits. The potential advantages of this method over existing methods to assess language comprehension in handicapped as well as nonhandicapped populations were described.

Aptitude↗