Biomedical subjects
P Gordon
Publications and source records attributed to P Gordon.
Serious bacterial infections in children. When can outpatient treatment be used?
Several studies now support outpatient treatment of many serious bacterial infections in children, such as periorbital or buccal cellulitis, urinary tract infection, pneumonia, and abscess. However, an appropriate agent, that is, a third-generation cephalosporin with a long half-life, must be available and its effectiveness properly researched. In addition, children must be free of other illnesses and able to ingest fluids and maintain hydration, and their parents must be willing and able to cooperate with an outpatient treatment regimen. Family physicians can maintain the close patient and family contact needed to facilitate this form of therapy.
Conservation therapy for breast cancer following augmentation mammaplasty.
Breast conservation therapy (wide local excision, axillary lymph node dissection, and whole-breast irradiation) is an increasingly popular alternative to mastectomy for breast cancer patients. A sizable (and growing) number of breast cancers occur in women with prior augmentation mammaplasty. Augmented breast cancer patients are currently being treated with conservation therapy, but no study has investigated complications and cosmetic results of radiation therapy specifically in this group of women. Between 1981 and 1988, we used conservation therapy in 17 augmented breast cancer patients. Fifteen patients were available for follow-up. In 10 (67 percent), significant capsular contracture occurred in the irradiated breast an average of 12 weeks following completion of treatment. Four patients have undergone revisionary surgery to correct symptoms arising from contracture. This poor outcome contradicts the results reported in previously published studies. We conclude that irradiation of the breast for cancer in augmented women results in a high incidence of scar-tissue contracture and poor cosmetic results.
A new robust index for measuring isokinetic trunk flexion and extension. Outcome from a regional study.
The purpose of this study was 1) to provide normative data for isokinetic trunk strength as measured by peak torque, best work repetition, and a new composite variable, "muscle performance index"; and 2) to examine the effects of protocol velocity, subject age, gender, height, and weight on these measurements. A significant decrease in peak torque of extension for females (P less than 0.0001) was seen as protocol velocity increased, but no differences were seen in males. A statistically significant amount (0.5-0.7) of the variance in isokinetic measurements was explained by subject age, height, and weight. Multivariant analysis of covariance showed the effects of these variances to be significant on all measurements except for the muscle performance index, which was unaffected by protocol velocity and remained stable without adjustments for subject age, weight, or height.
The computerized Tower of Hanoi: a new form of administration and suggestions for interpretation.
A computerized version of the Tower of Hanoi with a new form of administration was administered to two different groups, 15 men and 22 women, who were university students reporting normal psychological histories, and 24 traumatically brain-injured patients (20 men and 4 women). Scores on this test for both groups can be interpreted as an index of ability to solve problems and of learning strategies. Men and women scored differently on the task, i.e., women used different strategies than men to solve problems.
Choosing the best camera system.
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A model of service.
General practice may become the focus for primary and community care, but strong community health services remain important. Pam Constantinides and Pat Gordon propose some scenarios for the 1990s.
Verb-based versus class-based accounts of actionality effects in children's comprehension of passives.
Several studies have shown that children perform worse on tests of passive comprehension when the verb is non-actional than when it is actional. Most existing accounts focus on the semantic characteristics of the class of non-action verbs in explaining this difference. An alternative is a "verb-based" account in which passives are initially learned verb by verb, and children hear fewer non-actional passives in their language input. An analysis of the passives heard by Adam, Eve and Sarah (Brown, 1973) found more actional than non-actional passives, consistent with the verb-based account. In a second study, children tested for passive comprehension were re-tested a week later. The verb-based account predicts that children should show a consistent pattern of responses for individual verbs on test and re-test. Such consistency was found, with some inconsistency due to improvement over the re-test. Further analyses showed no effects of affectedness in explaining children's problems with passives. Finally, we discuss whether a mixed model containing both verb-based and class-based mechanisms is required to explain the actionality effects.
A double-blind clinical study comparing the safety, tolerance and efficacy of ioversol and iohexol in intravenous urography.
A double-blind trial in 80 patients showed no significant difference in the efficacy, tolerance and safety for intravenous urography between the new contrast medium Ioversol (Optiray Mallinckrodt Inc.) and the well established medium Iohexol (Omnipaque, Nycomed [UK] Ltd). Minor transient rises in AST/ALT were noted in approximately 10% of each group which were regarded as clinically insignificant. Both media were well tolerated with no significant side-effects.
The effect of HIV-1 infection on the lipid fatty acid content in the membrane of cultured lymphocytes.
Elevations in the levels of unsaturated fatty acids (FAs) in membrane lipids lead to an increase in cell membrane fluidity and may also be involved in cell fusion and death through the loss of normal membrane function and integrity. Since the infection of susceptible cells with HIV leads to cell fusion and subsequent loss of viability, the present study was undertaken to see whether HIV infection can alter the relative content of unsaturated FAs in the host cell membrane and to determine whether this change correlates with cell death. Peripheral lymphocytes (PBLs) of a healthy donor and two CD4+ cell lines were chosen: MT-4, which is killed following HIV infection, with significant cell death being observed 5 days postinfection, and H9 which is not killed. Measurements of FA content of the two cell lines and PBLs, either before or at 6, 24, and 48 h after infection, showed a significant rise in the concentration of unsaturated FAs followed by a drop in the concentration of saturated FAs in the MT-4 cell line. With regard to the H9 cell line similar results were obtained at 6 h from infection. However, at 24 and 48 h the concentrations of saturated FAs returned to preinfection levels while the concentrations of unsaturated FAs dropped to levels even lower than those obtained at zero time. No significant changes in FA composition were found with PBLs.
Communication strategies in caring for the underserved.
Physicians face numerous challenges in caring for underserved patients. These include both structural barriers, such as the increasing ranks of the uninsured, and contextual barriers. Contextual problems are embedded within the communication between doctors and patients. Communication between doctors and poor patients fails principally because of inadequately shared information and a power asymmetry in the relationship. This paper addresses specific strategies which practitioners and educators can use to improve communication with poor patients and assist in their empowerment. These strategies include employing attentive patient care, attending to the use of jargon, and using self-empowering language.
Effect of long-term inhibition of gonadotrophin secretion by the gonadotrophin-releasing hormone agonist, buserelin, on sex steroid secretion and ovarian morphology in polycystic ovary syndrome.
In order to investigate the effect of long-term suppression of the gonadotrophin axis in polycystic ovary syndrome, eight affected subjects were given s.c. infusions of gonadotrophin-releasing hormone (GnRH) agonist buserelin for 12 weeks. Hormone measurement and ultrasound studies were carried out weekly, from 6 weeks before to 12 weeks after administration of buserelin. An overnight dexamethasone-suppression test was carried out before and after treatment. Maximal suppression of LH to below the lower limit of that in normal subjects occurred after 6 weeks of treatment with buserelin. Plasma testosterone and androstenedione fell to normal levels during the infusion but reached pretreatment levels during the follow-up period. There was no effect of buserelin on plasma dehydroepiandrosterone sulphate or sex hormone-binding globulin. Ovarian size decreased significantly during the infusion with the disappearance of cysts in six subjects. After cessation of buserelin therapy, there was rapid and spontaneous ovulation which occurred within 3 weeks in all subjects. The results suggest that treatment with this GnRH agonist facilitates ovulation in this condition.
Lentigo maligna.
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Intrathecal fibrinolytic therapy after subarachnoid hemorrhage: dosage study in a primate model and review of the literature.
Because of the naturally low fibrinolytic activity of CSF many erythrocytes entrapped in subarachnoid blood clot undergo hemolysis in situ, releasing vasogenic oxyhemoglobin (OxyHb) in high concentrations around the basal cerebral arteries. In order to promote more rapid clearance of erythrocytes from the basal subarachnoid cisterns we are currently investigating intrathecal thrombolytic therapy with human, recombinant, tissue plasminogen activator (rt-PA) in a primate model of subarachnoid hemorrhage (SAH) and cerebral vasospasm (VSP). In the present study 16 monkeys were divided into 4 groups of 4, and each group received a different dose of sustained-release gel rt-PA at the time of experimental SAH. Cerebral angiography seven days later showed that whereas no VSP occurred in the groups receiving 0.5 or 0.75 mg of rt-PA, mild to moderate VSP occurred in the groups receiving 0.125 or 0.25 mg of rt-PA. Analysis of the combined 2 smaller dosage groups revealed significant (P less than 0.05) reduction of lumen caliber in the clot-side internal carotid (C3 and C4), proximal anterior cerebral (A1) and middle cerebral (MCA) arteries. Gross subarachnoid clot remained in all of the animals in the 0.125 and 0.25 mg dose groups, in 2 of the animals in the 0.5 mg dose group, and none of the animals in the 0.75 mg dose group. It was concluded that 0.75 mg of gel rt-PA is sufficient to completely lyse a 4.25 ml SAH and prevent VSP in our primate model. The literature on fibrinolysis and erythrocyte clearance in cerebrospinal fluid (CSF) is reviewed.
Safety and efficacy of intrathecal thrombolytic therapy in a primate model of cerebral vasospasm.
To test the safety of a large intrathecal dose of human recombinant tissue plasminogen activator (rt-PA), 6 cynomolgous monkeys were given 10 mg of rt-PA (mean, 2.7 mg/kg) through an Ommaya reservoir after craniectomy and dissection of the basal cisterns. Bleeding occurred briefly at the incision in 2 animals; otherwise the clinical condition of all 6 remained normal throughout the postoperative period. Systemic fibrinolysis did not occur, and gross and microscopic examination of the brain and meninges revealed no abnormality. Next, we evaluated the efficacy of unilateral administration of rt-PA suspension (0.5 mg) plus slow-release gel rt-PA (1.25 mg) in lysing a bilateral subarachnoid clot and preventing vasospasm in a randomized, placebo-controlled trial. Sixteen monkeys were divided randomly into 2 equal groups, each of which underwent baseline cerebral angiography, followed by frontotemporal craniectomy and induction of subarachnoid hemorrhage on the left side and then on the right. Before closure on the right side either rt-PA or an equal volume of placebo was injected into the subarachnoid space. On day 7 angiography was repeated, and the animals were killed under anesthesia for necropsy. One of the animals in the placebo group developed a cerebral infarction on day 5. In the placebo group significant vasospasm occurred in all major right and left-sided anterior cerebral vessels (P less than 0.01). No vasospasm occurred in the rt-PA-treated animals. Whereas gross subarachnoid clot was found in all animals in the placebo group (mean clot weight 1.13 g), only a small fragment of clot was found in a single rt-PA-treated animal.(ABSTRACT TRUNCATED AT 250 WORDS)
Percutaneous transtracheal high frequency jet ventilation as an aid to difficult intubation.
A case is described where prophylactic high frequency jet ventilation through a percutaneous transtracheal cannula was performed. This guaranteed adequate ventilation of a patient who was known to be difficult to intubate, enabling a paralyzing dose of succinylcholine to be given and intubation to be performed safely in a well oxygenated patient scheduled for coronary artery bypass grafting.
The effect of nonviral liver damage on the T-lymphocyte helper/suppressor ratio.
In the present investigation an attempt was made to ascertain whether nonviral liver impairment in rats affects the THelper/TSuppressor ratio. Two hepatotoxic agents were used: (i) galactosamine (GA), which causes a drug-induced hepatitis-like damage, and (ii) orotic acid (OA), which induces fatty changes. Since these two substances act as antidotes to one another they were administered to rats either separately or simultaneously. GA caused severe liver damage documented by a 104-, 48-, and 1.6- fold rise in the plasma concentrations of ALT, AST, and ALP and by multiple foci of hepatocyte necrosis. This was followed by a drop in TH/TS ratio from 2.25 observed in the controls to 0.89 in the GA-treated rats. All of these phenomena were prevented by concurrent administration of GA and OA. OA alone did not show an effect on the liver with respect to changes in plasma enzyme concentrations and by light microscopic analysis. However, OA caused a drop in the TH/TS ratio from 2.25 to 1.55. Neither GA nor OA produced a change in TH/TS ratios in in vitro experiments.
Count/mass category acquisition: distributional distinctions in children's speech.
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