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Biomedical subjects

J Carter

Publications and source records attributed to J Carter.

At least 235 records · Page 13Linked to original sources
PubMed1984

Lateral subluxation of the atlas in rheumatoid arthritis: a case report and post-mortem study.

The atlantoaxial joints of a patient with lateral subluxation of the atlas were studied post mortem by dissection. There was severe erosion of the left lateral atlantoaxial joint and an asymmetrical erosion of the cartilages of the median atlantoaxial joint which prevented reduction of the lateral subluxation. The atlantoaxial ligaments were remarkably intact. It is emphasised that osseous factors rather than ligaments confer lateral stability to the atlantoaxial joints and that destruction of these leads to lateral subluxation.

Arthritis, Rheumatoid↗
PubMed1984

Cranial dystonia: double-blind crossover study of anticholinergics.

In patients with cranial dystonia, we compared the effects of central anticholinergic, peripheral anticholinergic, and placebo treatments in a double-blind crossover study. One of the nine patients who completed the study improved markedly with central anticholinergic therapy. The three treatments were indistinguishable in the other eight patients except for the higher incidence of central and peripheral anticholinergic side effects with trihexyphenidyl.

Adult↗
PubMed1984

Idiopathic unilateral disc edema. The big blind spot syndrome.

Unilateral edema of the optic disc without any evidence of increased intracranial pressure or optic nerve dysfunction is an uncommon problem. We describe two patients with "the big blind spot syndrome" who presented with unilateral disc edema and normal optic nerve function except for an enlarged blind spot. The course was self-limited in both patients. The presenting neuro-ophthalmologic signs and symptoms were similar to those of intracranial hypertension. It can be distinguished from other causes of a unilateral swollen disc by the lack of intracranial hypertension, normal optic nerve function, and the absence of marked venous engorgement or peripapillary hemorhages. Its early recognition may spare the patient unnecessary diagnostic procedures.

Adolescent↗
PubMed1984

Automated objective refractometers.

We have shown how the modern-day analysis of the aerial image produced by an indirect ophthalmoscope forms the basis for automated objective refraction. Objective automated optometers present with the advantages that they: record rapidly, thereby minimizing the effects of accommodative fluctuation and/or fixation instability, demand only low-level technical skill on the part of the operator, demand little of the patient beyond passive cooperation. Refractive findings obtained using objective automated refractors are counterparts of retinoscopic prescriptions and correlate about as well with subjective findings as do those obtained by the proficient retinoscopist.

Ophthalmoscopy↗
PubMed1983

Parental reproductive problems and gestational hormonal exposure in autistic and schizophrenic children.

The incidence of infertility and two or more spontaneous abortions was significantly increased in the parents, compared to that reported for the general population, in this pilot survey of 61 patients evaluated for major childhood psychoses. In addition, 18% of our patients had a history of early gestational exposure to progesterone/estrogen compounds (9 patients) and to cortisone (2 patients). This frequency of gestational hormoné exposure was significantly increased over that in normal infants from three published surveys. However, in 5 of the 11 patients with gestational hormonal exposure, the medication was prescribed because of prior parental reproductive problems or bleeding during the current pregnancy. Therefore, it cannot be concluded that the gestational hormonal exposure was causally related to the psychoses present in these patients. In order to obtain more conclusive data, there will need to be continued monitoring of parental reproductive histories and gestational environmental exposures in autistic and schizophrenic children.

Autistic Disorder↗
PubMed1983

Relationship of adrenergic and electrical brain stimulation induced feeding responses.

Electrical and adrenergic brain stimulation can induce eating in satiated animals. This report explores the interrelationship of brain feeding systems mediating eating in response to norepinephrine and electrical stimulation of the hypothalamus in rats. It was found that simultaneous adrenergic and electrical brain stimulation resulted in a significant increase in food intake as compared to each stimulation condition alone. Furthermore, pharmacological blockade of the alpha-adrenergic receptors in the hypothalamus attenuated feeding in response to adrenergic, but not electrical brain stimulation. Results are interpreted to suggest that these feeding systems are independent at the level of the diencephalon. The role of the vagus nerve as an efferent link through which these brain systems may influence feeding behavior is discussed.

Animals↗
PubMed1983

Dopamine, dobutamine, and phentolamine effects on pulmonary vascular mechanics.

The pressure-flow (P-Q) relationship of the pulmonary vasculature, in an isolated canine lobe perfused under classical zone II conditions, can be characterized by a rectilinear segment at high flow, a curvilinear segment at low flow, and a pulmonary arterial pressure (Ppa) that exceeds alveolar pressure at zero flow. This demonstrates the presence of critical closure in the pulmonary vascular bed. Effects of drugs on pulmonary vascular resistance (PVR) must take the normal P-Q relationship into account. We examined the effect of dopamine (D) and dobutamine (DB), alone and in combination with phentolamine (P), on the slope of the rectilinear segment of the P-Q curve (equivalent to vascular conductance), the extrapolated Ppa intercept (Ppai), and the Ppa at zero flow (Ppaz). Low-dose D (0.4-0.8 mg) and DB (1.0-5.0 mg) did not significantly alter any parameter from control. Higher-dose D (1.2-6.8 mg) and DB (13-38 mg) decreased vascular conductance 32.3 +/- 12.1 (SE) to 50.45 +/- 5.6% (P less than 0.05), and P alone increased conductance 12.0 +/- 2.6% (P less than 0.01) from control with no significant effect on Ppai or Ppaz. The change in conductance with D and DB alone was abolished when either drug was given in combination with P. Ppaz and Ppai decreased significantly from control with DB in combination with P when no significant effect on vascular conductance was noted. The results suggest that lung vessels determining changes in flow resistance are pharmacologically distinct from those subserving critical closure in the pulmonary vascular bed.

Animals↗
PubMed1983

Bone marrow necrosis in acute leukemia.

2 patients with premortem marrow necrosis in acute leukemia are discussed. A review of the course of each patient plus those in the literature suggests that premortem marrow necrosis may not be a poor prognostic sign in acute lymphoblastic leukemia but generally precedes a prolonged and fatal pancytopenia in acute myelogenous leukemia. The technetium-99m rhenium sulfur colloid marrow scan was found to be of value in assessing the extent and degree of necrosis of the marrow as well as in documenting and predicting marrow recovery following chemotherapy.

Aged↗
PubMed1983

Digital angiography in the pediatric patient with congenital heart disease: comparison with standard methods.

Digital subtraction angiography (DSA) permits high-resolution cardiac imaging with relatively low doses of contrast medium and reduced radiation exposure. These are potential advantages in children with congenital heart disease. Computer-based DSA (30 frames/sec) and conventional cutfilm angiography (6 frames/sec) or cineangiography (60 frames/sec) were compared in 42 patients, ages 2 months to 18 years (mean 7.8 years) and weighing 3.4 to 78.5 kg (mean 28.2 kg). There were 29 diagnoses that included valvular regurgitant lesions, obstructive lesions, various shunt abnormalities, and a group of miscellaneous anomalies. For injections made at a site distant from the lesion and on the right side of the circulation, the mean dose of contrast medium was 60% to 100% of the conventional dose given during standard angiography. With injections made close to the lesion and on the left side of the circulation, the mean dose of contrast medium was 27.5% to 42% of the conventional dose. Radiation exposure for each technique was markedly reduced in all age groups. A total of 92 digital subtraction angiograms were performed. Five studies were suboptimal because too little contrast medium was injected; in the remaining 87 injections, DSA and conventional studies resulted in identical diagnoses in 81 instances (p less than .001 vs chance). The remaining six injections made during DSA failed to confirm diagnoses made angiographically by standard cutfilm angiography or cineangiography. We conclude that DSA usually provides diagnostic information equivalent to that available from cutfilm angiography and cineangiography, but DSA requires considerably lower doses of contrast medium and less radiation exposure than standard conventional methods.

Adolescent↗
PubMed1983

Changes in T and B lymphocyte populations in the lymph nodes draining the uterus in pregnant mice.

Using indirect immunofluorescence and fluorescence microscopy, changes in the proportion of T and B lymphocytes in the para-aortic lymph nodes draining the pregnant uterus and the brachial nodes from the same animal were examined at 8, 15, 17 and 19 days of pregnancy and 2 and 6 days post partum. Syngeneic and allogeneic matings of CBA and C57BL10.ScSn mice were examined. There was a dramatic increase in the level of B cells in the para-aortic nodes after 15 days. This peaked around the time of parturition and did not fall until 6 days post partum. There was no change in the level of B cells in the brachial nodes. There was an indication from syngeneic and allogeneic matings of CBA mice that the percentage of T cells dropped during the second half of pregnancy. It is concluded that allogenicity, seminal plasma, implantation, multiparity, the placenta and the male fetus were not responsible for the observed increase in the level of B lymphocytes.

Animals↗
PubMed1983

FACS analysis of changes in T and B lymphocyte populations in the blood, spleen and lymph nodes of pregnant mice.

Using the fluorescence-activated cell sorter (FACS), the percentages of T and B lymphocytes in the peripheral blood, spleen and lymph nodes of CBA syngeneic and allogeneic pregnancies were determined. At 19 days of syngeneic pregnancy, the level of T cells in the blood had decreased and that of B cells had increased. In the spleen, a decrease in both T and B cells occurred earlier in pregnancy and had returned to control levels by 19 days. During the last few days of pregnancy, the para-aortic lymph nodes (PALN) draining the pregnant uterus of syngeneically mated mice showed a 1 . 7-fold increase in the level of B cells over that in virgin controls. The T-cell level dropped at the end of pregnancy by approximately 10%. There was no change in T- or B-cell status in the brachial (underarm) nodes taken from the same animals.

Animals↗
PubMed1983

Pregnancy induces an increase in the number of immunoglobulin-secreting cells.

The effect of pregnancy on the immune status of CBA mice has been measured in terms of Ig-secreting cells. Reversed plaque assays show that there is a considerable increase in numbers of IgG- and, to a lesser extent, IgM-secreting cells in the para-aortic lymph nodes. Similar but muted responses were observed in the spleen and among the lymphocytes of the peripheral blood. Analysis of cells sorted for intensity of staining for surface Ig in a fluorescence-activated cell sorter (FACS), shows that Ig-secreting cells are confined to a population of very weakly staining cells. The 'response' in syngeneic pregnancies (CBA x CBA) is at least as great as that seen in allogeneic pregnancies (CBA x C57). Active immunity to a xenogeneic erythrocyte antigen is potentiated by pregnancy.

Animals↗
PubMed1982

Turnover of the molecular forms of acetylcholinesterase in the rat diaphragm.

The turnover of acetylcholinesterase (AChE) and its molecular forms was measured by following the loss of enzyme activity in the right hemidiaphragms of Sprague-Dawley rats treated with cycloheximide, 20 mg/kg, every 4 h. This treatment inhibited 96% of the incorporation of [3H]leucine into muscle protein. After 8 h of treatment, the total AChE activity of the diaphragm decreased by 17% (P less than 0.01). Assuming first-order exponential kinetics, a half-life of 30 h and an hourly turnover of 180 units were calculated. The measured accumulation of AChE activity at a ligature on the phrenic nerve indicated that axonal transport contributed trivially to this turnover. Sucrose density gradient experiments showed that the cycloheximide-induced low of AChE activity was restricted to the 4S enzyme, which had an apparent half-life of 6.2 h.

Acetylcholinesterase↗
PubMed1982

Effect of alphavirus infection on mouse embryos.

Seven strains and mutants of the alphaviruses, Semliki Forest virus and Sindbis virus, differed in their lethality for mouse embryos and their mothers. The A7 strain and the neurovirulence mutant M103 of Semliki Forest virus were selected for detailed comparison. A7 produced 100% lethality of mouse embryos but was avirulent for their mothers. M103 did not kill embryos or their mothers but did induce postnatal immunity. This immunity could be induced in utero or by suckling to an immune mother. Infectious virus could be recovered from the brain, blood, and embryos of mice infected with A7. Mice infected with M103 developed a viremia of similar titer, but virus could not be recovered from brain or embryos. Electron microscopy showed multiplying virus in trophoblast and fetal tissue after infection with A7, but no virus could be detected in such tissue after infection with M103. Cultures of ectoplacental cone trophoblast cells incubated in the presence of A7 or M103 showed multiplying A7 in the giant cells, but no M103. It is concluded that A7 can traverse both the blood-brain barrier and the placenta, whereas M103 can traverse neither.

Animals↗