Search PubMed⌕ Search

Biomedical subjects

J C Anderson

Publications and source records attributed to J C Anderson.

At least 19 recordsLinked to original sources
PubMed1992

Synaptic connections of physiologically identified geniculocortical axons in kitten cortical area 17.

Single geniculocortical axons were recorded in the cortical white matter of kittens and adult cats by using micropipettes filled with horseradish peroxidase (HRP). Of 41 axons recovered in 4-5 week old kittens, three well-filled axons arborized in area 17; the remainder were incomplete or arborized in area 18. One axon had Y-like physiological properties, two were X-like. They were recovered from two 34-day-old kittens. All three axons formed clustered arborizations, mainly in layer 4A. Electron microscopic (EM) analysis of 50 boutons from kitten and 38 boutons from adult controls revealed that the boutons from kitten made synapses more frequently on spines (91% of targets) than did the boutons from the adult (71%). One X-like axon in kitten also had a collateral projection that made synapses in layer 1; this has not been seen in adult cats. In overall extent, the axons from kitten fell within the adult range.

Aging↗
PubMed1992

The neurons in layer 1 of cat visual cortex.

We have examined the morphology of neurons in layer 1 by injecting them intracellularly with lucifer yellow in lightly fixed brain slices (250 microns thick) taken from the medial bank of area 17 in adult cats. Of 22 neurons with well-filled dendrites, 16 had smooth dendrites, two had sparsely spiny dendrites (less than 200 spines) and, unexpectedly, four had spiny dendrites typical of pyramidal cells. The axon was generally not well filled. Computer reconstructions showed that parts of the dendritic tree had been lost in the sectioning. Nevertheless, measurements of the length of intact dendrites suggested an average diameter of the dendritic tree of 220 microns. The density of the neurons was such that the dendritic trees of about six neurons cover each point in layer 1. Thus, despite the very low density of neurons that characterizes layer 1, there are more than sufficient neurons to sample from the entire representation of the visual field in area 17.

Animals↗
PubMed1992

Transvaginal sonography of cervical width and length during pregnancy.

Transvaginal ultrasonography has been proposed as a reliable method of assessing dimensions of the cervix. The purpose of the current investigation was to establish normative data for cervical width and length during pregnancy. This information may be helpful in predicting patients at risk for preterm birth. A transvaginal 5 or 7.5 MHz transducer was used on 132 consecutive low-risk pregnant women undergoing evaluation for gestational dating purposes. Even in cases of patient obesity or an empty bladder, high resolution was possible and permitted cervical measurement in all but one case. The external cervical width at the vaginal fornices was found to increase with advancing gestation (R = 0.512, P < 0.005). The cervical length from internal os to external os was found not to change with advancing gestation (R = 0.11, P = 0.30). Using these normative data, investigation is recommended to determine whether measuring cervical width and length is useful in predicting preterm labor and delivery.

Anthropometry↗
PubMed1991

Outcome of 1500 consecutive chorionic villus samplings.

OBJECTIVE: To evaluate the clinical complications and diagnostic problems of chorionic villus sampling. DESIGN: A pragmatic retrospective analysis. SETTING: Tertiary obstetric referrals mostly to private practice; sampling carried out at Royal Prince Alfred Hospital; diagnostic analysis usually at Oliver Latham Laboratory, or the Clinical Immunology Research Centre, Royal Prince Alfred Hospital, New South Wales. PATIENTS: 1500 women in the first trimester of pregnancy requesting prenatal diagnosis because of a risk of chromosomal or inherited genetic disorder in the fetus. INTERVENTIONS: Ultrasound-guided passage of a catheter into the chorion through the cervix. MAIN OUTCOME MEASURES: Incidence of unintended abortion, preterm births, low weight infants and discrepant karyotypes. RESULTS: There were 42 unintended abortions (3.0%), about 0.4% higher than the background abortion rate in women of similar age. Abortion did not occur more frequently in women with vaginal bleeding earlier in that pregnancy. Rates of preterm births and birth of low birthweight infants did not differ from the general population. A second diagnostic test was required in 68 women (4.5%). Mosaicism and tetraploidy were usually confined to the chorion. CONCLUSION: Chorionic villus sampling is an acceptable diagnostic test. Amniocentesis should be offered to patients who show mosaicism or tetraploidy.

Abortion, Spontaneous↗
PubMed1991

Increased hyaluronate synthesis and changes in glycosaminoglycan ratios and molecular weight of proteoglycans synthesised by cultured cervical tissue from ewes at various stages of pregnancy.

Culture of cervical tissue with radiolabelled precursors showed that, in pregnant ewes, net hyaluronate synthesis increased between days 120-140 but that the marked polydispersity of hyaluronate remained unchanged. In the less sulphated of two proteoglycan populations, the proportion of heparan sulphate increased and that of dermatan sulphate decreased, while the less polydisperse more highly sulphated species showed a significant increase in molecular weight with pregnancy.

Animals↗
PubMed1991

Uterine and fetal Doppler flow changes after intravaginal prostaglandin E2 therapy for cervical ripening.

Nineteen patients received prostaglandin E2 as a 2.5 mg gel (seven cases), 3.3 mg chip (five cases), or 10 mg controlled-release pessary (seven cases) for preinduction cervical ripening. Blood flow velocities did not change significantly for the uterine arcuate artery, fetal aorta, and umbilical artery circulations after any of the treatments. In no case did systolic/diastolic ratios consistently elevate above baseline values.

Blood Circulation↗
PubMed1990

Outpatient gamete intrafallopian transfer: a clinical analysis of 710 cases.

From February 1986 to June 1989 445 infertile couples were treated with a total of 710 treatment cycles involving laparoscopic gamete intrafallopian transfer (GIFT). The median age of the female partner was 33.5 years (range, 24 to 49 years) and the median duration of infertility was 4 years (range, 2 to 20 years). The final outcome of all 217 clinical pregnancies is known. There were 150 live births among which all but one baby survived, comprising 112 singleton births, 28 twin births, nine triplet births and one quadruplet birth. There were no still births, but there were two premature, multiple live births (one triplet, one quadruplet) among which no babies survived the neonatal period. Overall, 40 of the 152 potentially viable pregnancies were multiple (26.3%). Three of 206 potentially viable babies were born with congenital anomalies (1.5%). There were 50 clinical spontaneous abortions (24.8% of uterine pregnancies), one termination of pregnancy for Down's syndrome, and 14 ectopic pregnancies rate was 30.6% per laparoscopy and, among 740 initiated cycles, a live and surviving birth-per-initiated-cycle rate of 20.2%, or 33.7% to date per couple entering the programme. The 710 laparscopies resulted in two serious complications (0.3%), one of which required laparotomy. Eight other patients were admitted to hospital for rest and observation because of painful ovarian enlargement in the luteal phase. The total inpatient admission rate was 1.4%. Outpatient laparoscopic GIFT under general anaesthesia is a safe and effective procedure when conventional treatment for infertility has been unsuccessful.

Abortion, Spontaneous↗
PubMed1990

Effect of a single dose of oral pseudoephedrine on uterine and fetal Doppler blood flow.

Pseudoephedrine, a stereoisomer of ephedrine with alpha- and beta-adrenergic properties, is the active ingredient in over-the-counter oral decongestants. Its safety during pregnancy has not been studied adequately. The purpose of this investigation was to evaluate the effects of pseudoephedrine on uterine and fetal Doppler blood flows. Twelve healthy pregnant women between 26-40 weeks' gestation ingested a standard 60-mg dose of pseudoephedrine. A pulsed Doppler system was used to perform blood flow measurements of the uterine arcuate artery, fetal aorta, and umbilical artery before dosing, immediately thereafter, and at 15-minute intervals during the first 3 hours after drug ingestion. Blood flow velocities were not altered significantly after dosing in either the maternal or fetal circulation. In no case did absolute fetal or uterine blood flow velocities decrease significantly or systolic/diastolic ratios persistently elevate to abnormal values. We conclude that no significant alterations in the uterine or fetal circulations occur after the ingestion of a single dose of oral pseudoephedrine by healthy pregnant patients in the third trimester.

Administration, Oral↗
PubMed1990

Sonography of the musculoskeletal system.

Improved technology and the development of high-resolution transducers have made sonography of the structures of the musculoskeletal system possible. The vast majority of scientific reports on the value of sonography for imaging musculoskeletal abnormalities have been written only in the last decade. Sonography has several inherent advantages: it is relatively inexpensive, allows comparison with the opposite normal side, uses no radiation, and can be performed at bedside or in the operating room if necessary. The advent of MR imaging has revolutionized musculoskeletal imaging and may be used in many instances rather than sonography for evaluating the same abnormalities or anatomic structures. It is important, however, to keep in perspective what the different imaging techniques have to offer, and, if one is just as efficacious as the other, the least invasive and least expensive should be chosen whenever possible. The goal of this article is to review the applications of sonography to the evaluation of musculoskeletal disorders including tendon disease, soft-tissue masses, identification of foreign bodies, osteomyelitis, cellulitis, and certain joint abnormalities.

Aneurysm↗
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↗