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Biomedical subjects

J C Anderson

Publications and source records attributed to J C Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Collagen in dissecting aneurysms of the human thoracic aorta. Increased collagen content and decreased collagen concentration may be predisposing factors in dissecting aneurysms.

Biochemical investigations were made into dissecting aneurysms of the thoracic aorta by taking samples at 12 specific sites from aortas of 10 patients who had dissected with fatal results in comparison with samples from 10 matched controls. When sites actually involved in dissection were compared with corresponding sites in controls, there were highly significant increases in dry weight, amount of collagen, and total protein (all p less than 0.001) and a significant decrease in collagen concentration (p = 0.016). In contrast, when samples from sites within dissected aortas, but not involved in dissection, were compared with corresponding sites in controls, there were no significant differences. We therefore conclude that in dissecting aneurysms of the thoracic aorta, there is localized expansion of the aortic matrix, due to deposition of collagen and other proteins, which decreases the concentration of matrix constituents, including collagen. Clearly, the deposition of collagen could be a cause but not a consequence of dissection. The altered composition means that the aortic wall becomes weaker and less able to withstand the mechanical stresses constantly imposed upon it.

Aged↗
PubMed1990

Uterine and fetal Doppler flow changes from a single dose of a long-acting intranasal decongestant.

Oxymetazoline, an alpha-adrenergic agent, is the active vasoconstrictor in long-acting intranasal decongestants. This investigation studied the effects of oxymetazoline on the maternal and fetal circulations. Twelve healthy gravid patients in the third trimester (27-39 weeks) underwent flow velocity measurements by the same sonographer using a pulsed Doppler system (ATL Ultramark 4 machine). Maternal and fetal indices were recorded 15 minutes before dosing, immediately thereafter, and at 15-minute intervals during the first 2 hours after the drug was given. No significant changes were found in either the maternal blood pressures or pulse rates. Blood flow velocities did not change significantly from baseline for the uterine arcuate artery, fetal aorta, or umbilical artery circulations. In no case did absolute blood flow velocity decrease significantly or systolic/diastolic ratios elevate to worrisome values. For uncomplicated pregnancies, we conclude there are no significant acute changes in the maternal and fetal circulations after a single dose of intranasal oxymetazoline.

Administration, Intranasal↗
PubMed1989

Dystocia in late labor: determining fetal position by clinical and ultrasonic techniques.

A failure of adequate progression during late labor occurs often and may prohibit an accurate determination of the fetal head position from scalp edema or caput formation. This investigation was undertaken to determine whether ultrasonic evaluation could confirm or correct the digital examination impressions of the fetal head position. Eighty-six attempted vaginal deliveries had recent evidence for arrested cervical dilation after 7 cm or more. An occiput transverse position in 24 (28%) cases was diagnosed accurately, with the need for additional ultrasonic information only in the presence of scalp edema. Distinguishing between a persistent occiput posterior (15 cases, 17%) or anterior (47 cases, 55%) position was often inexact by palpation alone. Combined clinical and ultrasonic impressions allowed for a significantly more precise diagnosis. Ultrasonic imaging allowed for more security while waiting, more confidence with midforceps application, or a prompter decision for cesarean section, depending on the head position.

Adult↗
PubMed1989

Neurosonographic findings in infants treated by extracorporeal membrane oxygenation (ECMO).

Extracorporeal membrane oxygenation (ECMO) is an approved therapy for some neonates who have respiratory failure that is due to hyaline membrane disease, meconium aspiration, persistent pulmonary hypertension, congenital diaphragmatic hernia, or sepsis. The major complication of this therapy is hemorrhage, with intracranial hemorrhage having the highest morbidity and mortality. Seizures, incisional bleeding and bleeding in the pleural space, hypoxic-ischemic encephalopathy, renal failure, and cardiovascular complications account for most of the other complications. Cranial sonography provides an ideal imaging modality for baseline evaluation and daily follow-up; however, computed tomography and magnetic resonance imaging, because of better sensitivity, are important for assessment after ECMO. The changes in intracranial blood flow related to ECMO can be noninvasively evaluated by Doppler ultrasound modalities.

Cerebral Hemorrhage↗
PubMed1989

Ultrasonography of post-traumatic soft-tissue lesions.

This article highlights the varied uses of ultrasound for detection of trauma to soft tissues. The emphasis is on the diagnosis of tendon and muscle disruptions. Detection of soft-tissue foreign bodies by ultrasound, an important recent innovation, is also reviewed. Miscellaneous potential applications of ultrasound for diagnosing meniscal injuries, cartilage integrity, epidermoid cysts, and traumatic vascular malformations are discussed briefly. Ultrasound is efficacious because of its low cost, noninvasiveness, wide availability, and accuracy.

Achilles Tendon↗
PubMed1988

Intracranial arterial duplex Doppler waveform analysis in infants.

Duplex sonography of the brain was performed on 130 pediatric patients: 53 with normal brains, 22 with intracranial hemorrhage, 15 with hypoxic-ischemic encephalopathy, 29 with hydrocephalus requiring ventricular shunting, and 11 with ventriculomegaly without hemorrhage or shunting. Doppler arterial waveforms from the Circle of Willis showed increased pulsatility in 82% of patients with intracranial hemorrhage, 53% of patients with hypoxic-ischemic change, and in only 31% of patients with hydrocephalus requiring shunt and 36% of patients with ventriculomegaly without shunt or hemorrhage. Mean pulsatility was increased (p less than 0.05) in all groups except ventriculomegaly without hemorrhage or shunt. No statistical difference was found in the diagnostic efficiency of three indices of pulsatility (frequency index profile, pulsatility index, systolic to diastolic ratio).

Brain Ischemia↗
PubMed1988

Duplex ultrasonography as a noninvasive technique for assessing portal hemodynamics.

Duplex ultrasonography was evaluated as a noninvasive, quantitative technique of assessing portal hemodynamic characteristics. Portal blood flow measured by duplex ultrasonography was significantly decreased in patients with portal hypertension (450 +/- 86 ml/min) compared with control subjects (874 +/- 44 ml/min; p less than 0.001). Quantitative assessment of portal blood flow by duplex ultrasound correlated with qualitative portal perfusion grading by angiography, and direction of flow was always accurately determined by duplex ultrasonography. Although the angiographic portal perfusion grade did not change significantly in the early postoperative period after distal splenorenal shunting, a decrease in mean portal blood flow of more than 50 percent was documented by duplex ultrasonography. Duplex ultrasonography appears to be at least as accurate as angiography and is an acceptable alternative to this more invasive technique for the longitudinal assessment of portal blood flow.

Adult↗
PubMed1988

Pregnancies after ultrasound-guided fallopian insemination with cryostored donor semen.

Twenty-nine patients, previously treated unsuccessfully with a median 9.5 cycles of conventional intracervical donor insemination, were offered fallopian catheterization on the side of the dominant follicle and direct insemination at the presumed site of fertilization, the ampullary-isthmic junction. Forty-five of 50 cycles were associated with successful tubal catheterization and 6 of these cycles were conceptional. Five viable intrauterine pregnancies resulted. We conclude: (1) that direct sperm transfer to the fallopian tubes is possible without the need for anesthesia or operation; and (2) that at the time of ovulation, the fallopian tube isthmus can be catheterized without later interfering with ovum or embryo transport to the uterus. Optimum timing for fallopian catheterization in relation to ovulation and the risk of side effects both remain to be established.

Clinical Trials as Topic↗
PubMed1988

Increased collagenase activity is not detectable in cervical softening in the ewe.

Cervical tissue from ewes at various stages of pregnancy was examined for evidence that collagenase is involved in the process of cervical softening. Collagenase activity was detected in medium after 2-3 days culture of ovine cervical explants, but there was no significant difference in total enzymic activity produced by explants from non-pregnant, early pregnant or late pregnant animals when expressed as units/mg wet weight of tissue over five days in culture. Oestradiol infusion into ewes prior to parturition did not alter the enzyme activity subsequently produced in explant culture. However, the DNA concentration, and hence the number of cells per unit volume, decreased significantly with length of pregnancy, this effect being due to expansion of cervical tissue which occurs late in pregnancy. Thus, if collagenase activity is expressed relative to DNA and hence cell number, there is evidence for increased production per cell in order to keep the tissue concentration constant. However, as the concentration of collagen in cervix remains constant during pregnancy, the ratio of collagenase activity to collagen is also constant. It is therefore concluded that there is no evidence of a role for increased collagenase activity in cervical softening in the ewe.

Animals↗
PubMed1988

Glomerular basement membrane proteoglycans are derived from a large precursor.

The basement membrane heparan sulfate proteoglycan produced by the Englebreth-Holm-Swarm (EHS) tumor and by glomeruli were compared by immunological methods. Antibodies to the EHS proteoglycan immunoprecipitated a single precursor protein (Mr = 400,000) from [35S]methionine-pulsed glomeruli, the same size produced by EHS cells. These antibodies detected both heparan sulfate proteoglycans and glycoproteins in extracts of unlabeled glomeruli and glomerular basement membrane. The proteoglycans contained core proteins of varying size (Mr = 150,000 to 400,000) with a Mr = 250,000 species being predominant. The glycoproteins are fragments of the core protein which lack heparan sulfate side chains. Antibodies to glomerular basement membrane proteoglycan immunoprecipitated the precursor protein (Mr = 400,000) synthesized by EHS cells and also reacted with most of the proteolytic fragments of the EHS proteoglycan. This antibody did not, however, react with the P44 fragment, a peptide situated at one end of the EHS proteoglycan core protein. These data suggest that the glomerular basement membrane proteoglycan is synthesized from a large precursor protein which undergoes specific proteolytic processing.

Animals↗
PubMed1988

Humoral immunity to link protein in patients with inflammatory joint disease, osteoarthritis, and in non-arthritic controls.

Cartilage link protein of high purity was prepared and used in an enzyme linked immunosorbent assay (ELISA). Antibodies to link protein were sought in the sera of 98 patients with rheumatic disorders; 38 with rheumatoid arthritis (RA), 29 with osteoarthritis (OA), 13 with psoriatic arthritis (PA), nine with ankylosing spondylitis (AS), nine with systemic lupus erythematosus (SLE), and in 83 healthy controls. Antibodies were detected in all groups with the following prevalences: 21/83 normals, 9/38 RA, 7/29 OA, 7/13 PA, 3/9 AS, and 4/9 SLE. No statistically significant differences existed between the groups with regard to either prevalence or mean titre of anti-link antibodies. Serum antibodies to proteoglycan link protein appear to be no more common in patients with rheumatic disorders than in healthy controls.

Arthritis↗
PubMed1988

Effects of meal frequency on energy utilization in rats.

The effects of differences in meal frequency on body weight, body composition, and energy expenditure were studied in mildly food-restricted male rats. Two groups were fed approximately 80% of usual food intake (as periodically determined in a group of ad libitum fed controls) for 131 days. One group received all of its food in 2 meals/day and the other received all of its food in 10-12 meals/day. The two groups did not differ in food intake, body weight, body composition, food efficiency (carcass energy gain per amount of food eaten), or energy expenditure at any time during the study. Both food-restricted groups had a lower food intake, body weight gain, and energy expenditure than a group of ad libitum-fed controls. In conclusion, these results suggest that amount of food eaten, but not the pattern with which it is ingested, has a major influence on energy balance during mild food restriction.

Animals↗
PubMed1988

The evolution of ischemic cerebral infarction in infancy: a sonographic evaluation.

Cranial sonography provides a noninvasive, portable method for imaging the infant brain. This study describes the time-dependent, sonographic findings of infantile cerebral infarction, as well as computed tomographic (CT) scan and neuropathologic confirmation. Three hundred ninety-five infants under 18 months of age were sonogrammed over a period of 18 months. Three infants were diagnosed by cranial sonography and confirmed by CT scan and/or autopsy to have acute ischemic cerebral infarcts. The cases were followed with serial cranial sonograms for up to 18 months of age. The acute sonographic findings included a hyperechoic zone around the infarcted tissue. The subacute infarct had a checkerboard pattern, while the chronic infarcts were anechoic.

Cerebral Infarction↗
PubMed1988

Collagenase inhibitor concentration in cultured cervical tissue of sheep is increased in late pregnancy.

An inhibitor of collagenase was released from cultured cervical tissue of sheep and the amounts released were greatest from tissue in late pregnancy (145-146 days). The molecular weights of material with inhibitory activity, estimated by gel filtration of extracted inhibitor, at different stages of pregnancy were different, i.e. 20,000 from extracts of late-pregnant and post-partum samples and 29,000 from extracts of non-pregnant samples. Inhibitor from culture supernatants had a molecular weight of 42,000. We conclude that the inhibitor has binding characteristics and molecular weights similar to those of the tissue inhibitor of metalloproteinase.

Animals↗
PubMed1988

Artifacts and diagnostic pitfalls on magnetic resonance imaging: a clinical review.

High field MRI of the brain occasionally exhibits imaging artifacts; most artifacts are obvious and easily recognized, but some are subtle and mimic disease. A thorough understanding of brain MRI artifacts is important to avoid potential diagnostic pitfalls. Some imaging techniques or procedures could be utilized to remove or identify artifacts. These include additional projections, different pulse sequence, and 90 degree shift of phase-encoding gradient. The use of respiratory gating or cardiac gating may also improve image quality by reducing some of the motion-related artifacts.

Adolescent↗