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Biomedical subjects

B Gordon

Publications and source records attributed to B Gordon.

At least 127 records · Page 7Linked to original sources

Simultaneous analysis of furosemide and bumetanide in horse plasma using high performance liquid chromatography.

A high performance liquid chromatographic method is described for the simultaneous determination of furosemide and bumetanide in horse plasma. The C8 (3 microns) reversed phase column (4.8 x 150 mm) provided clear separation of furosemide and bumetanide with other components present in the horse plasma. The detection limit for both the drugs was 10 ng/mL. Both drugs were stable in plasma (at natural or acidic pH) for up to 24 h. The method is sufficiently sensitive to detect furosemide levels in plasma obtained from horses receiving a therapeutic dose of furosemide.

Animals↗

Local cerebral glucose abnormalities in mild closed head injured patients with cognitive impairments.

Mild-moderate closed head injury (CHI) can be followed by neuropsychological impairments in recent memory and attention, despite the absence of discernible structural abnormalities in a significant number of patients. To determine whether CHI may result in cerebral glucose metabolic abnormalities, we used fluorodeoxyglucose (FDG) technique with PET imaging to measure local cerebral metabolic rates for glucose (LCMRGlu) in three CHI patients and three matched normal controls. The CHI patients were between 3-12 months post-injury. All had deficits in attention and recent memory shown by neuropsychological testing. CT, MRI, EEG and drug screens were negative at the time of PET scanning. Subjects were engaged in a vigilance task throughout the initial 30 min following FDG administration. Group comparisons were made using t tests. There were no significant group differences found in global glucose metabolic rate. Nevertheless, the CHI group exhibited significantly decreased LCMRGLu in medial temporal, posterior temporal, and posterior frontal cortices, as well as in the left caudate nucleus. LCMRGlu was significantly increased, relative to controls, in anterior temporal and anterior frontal cortices. These results suggest that CHI patients can have regional glucose metabolic abnormalities, indicative of altered neuronal function, despite the absence of discernible anatomic abnormalities.

Brain↗

6-Hydroxydopamine treatment and beta adrenergic receptor binding in kittens. Relation to visual cortical plasticity.

Under some circumstances intraventricular administration of 6-OHDA decreases visual cortical plasticity of kittens; the mechanism for this change is not known, but depletion of norepinephrine (NE) is not the entire explanation. We have examined the effects of 6-OHDA treatment on beta adrenergic receptor binding in kitten visual cortex. Subjects were given vehicle solution alone, a low dose of 6-OHDA which depleted cortical NE without affecting visuocortical plasticity, or a higher dose of 6-OHDA which depleted cortical NE and decreased visuocortical plasticity. Drugs were administered in single daily injections via intraventricular cannulas. Saturation assays were performed on homogenates of visual cortical tissue using 125I-pindolol (30-400 pM) along w/ isoproterenol (237 microM) as a cold competitor. We measured radioactivity bound to tissue and retained on filters and analyzed the data using the EBDA computer program (McPherson 1983, 1985); we determined the affinity constant (Kd) and receptor density (Bmax) in multiple assays for each animal. Despite 75-90% NE depletion in both experimental groups, only the group receiving the lower dose of 6-OHDA showed any evidence of supersensitivity. The Kds did not differ among the groups. The data suggest that the effects of 6-OHDA on visuocortical plasticity are not secondary to beta adrenergic supersensitivity.

Animals↗

Family members' perspectives on psychiatric hospitalization and discharge.

Families of currently hospitalized patients in an extended-care psychiatric facility were interviewed concerning their views of hospitalization and discharge. Although most were sad that their relative was hospitalized, only a third felt that they would rather be caring for their relative at home. Families felt communication with hospital staff was poor and many of their needs were unmet. Families indicated a number of concerns around discharge. If clients were to be discharged soon, most families felt the clients needed a highly structured supervised living arrangement.

Adult↗

Comparison of outpatient care of discharged state hospital and non-hospitalized psychiatric emergency room patients.

The present article compares a cohort discharged from two state hospitals in a large urban area with a cohort referred for outpatient services from a psychiatric emergency room. Both cohorts were referred into the same community mental health system of services. The two cohorts are examined in terms of clinical and social demographic characteristics, in part to consider how distinct the two populations appear to be. In addition, patterns of initial contact and the nature and amounts of community services received by each group are compared. Based on these comparisons, some conclusions are drawn regarding the way in which these two groups are served by the community system.

Adolescent↗

Outpatient compliance of psychiatric emergency room patients by presenting problems.

In the present study, a cohort of patients who came to a psychiatric emergency room in a general hospital, and were not referred for hospitalization, were analyzed in regard to the amount and rate of subsequent contact with community mental health and substance abuse agencies. Patterns of service receipt and the differential impact of service use on hospitalization and/or return visits were analyzed by three major problem types: (1) psychiatric; (2) psychiatric/substance abuse; and (3) substance abuse. The analysis of these subgroups yielded valuable information about how the service system and/or different groups of patients in crisis respond to the system.

Adolescent↗

Preserved learning of novel information in amnesia: evidence for multiple memory systems.

Four of five patients with marked global amnesia, and others with new learning impairments, showed normal processing facilitation for novel stimuli (nonwords) and/or for familiar stimuli (words) on a word/nonword (lexical) decision task. The data are interpreted as a reflection of the learning capabilities of in-line neural processing stages with multiple, distinct, informational codes. These in-line learning processes are separate from the recognition/recall memory impaired by amygdalohippocampal/dosomedial thalamic damage, but probably supplement such memory in some tasks in normal individuals. Preserved learning of novel information seems incompatible with explanations of spared learning in amnesia that are based on the episodic/semantic or memory/habit distinctions, but is consistent with the procedural/declarative hypothesis.

Adolescent↗

Metabolic changes in Alzheimer's disease.

Patients with Alzheimer's disease (AD) and matched controls fasted for 24 hours, and serial glucose, pyruvate, lactate, beta-hydroxybutyrate, acetoacetate, insulin, and glucagon levels were measured. Patients with AD showed a glucose insulin correlation pattern over the 24 hours that differed from the control group. These differences may be secondary to weight loss or to other metabolic or nutritional factors affecting the AD patients.

3-Hydroxybutyric Acid↗

Use of stapling instruments to aid in the removal of ovarian tumours in mares.

Ovarian granulosa theca cell tumours were removed surgically in 10 mares. Stapling instruments were used to facilitate haemostasis of the ovarian pedicle in five out of 10 cases and as a sole method of haemostasis in the remaining five cases. Postoperative haemorrhage from the ovarian pedicle was suspected in only one case. All cases survived long term follow-up from six months to four years. Results from this series of cases indicate that stapling instruments provide a rapid, easy and efficient means of ligating ovarian pedicles when performing ovariectomy in the mare.

Animals↗

Language dysfunction in early- and late-onset possible Alzheimer's disease.

Disproportionate involvement of language has been claimed to be a distinguishing feature of Alzheimer's disease (AD) with onset before age 65. We tested this hypothesis in a group of 133 patients with possible AD by NINCDS criteria. Sixty-one had onset of symptoms prior to age 65; the remaining 72, at 65 or later. The two groups were well matched on overall dementia severity as measured by the Mini-Mental State Exam. Using standardized tests, we did not find any significant differences in the severity of language dysfunction between the two groups, particularly after controlling for greater attention/concentration deficits in the early-onset group. Previous reports of differences in language dysfunction between early- and late-onset AD may have been due to small sample sizes and nonstandardized testing.

Age Factors↗

Magnetic resonance imaging of cerebral lesions in patients with the Sjögren syndrome.

Thirty-eight patients with the primary Sjögren syndrome, 16 with active neuropsychiatric manifestations and 22 without clinical evidence of central nervous system involvement had magnetic resonance (MR) imaging. Eight patients had focal neurologic deficits (6 of these also had psychiatric, or cognitive dysfunction), and 8 had psychiatric or cognitive abnormalities alone. Magnetic resonance imaging showed abnormal results in 12 of 16 (75%; 95% CI, 48 to 93) patients with active central nervous system disease (67 focal lesions predominantly within the subcortical and periventricular white matter), and in 2 of 22 (9%; 95% CI, 1 to 29) patients without clinical evidence of central nervous system disease (P less than 0.0001). Seven of eight patients with focal neurologic deficits and 5 of 8 patients with psychiatric or cognitive dysfunction alone had abnormal results on MR imaging. Magnetic resonance imaging was more sensitive in the subgroup with focal deficits, (sensitivity, 88%; 95% CI, 44 to 97) than computerized axial tomography or cerebral angiography. Magnetic resonance imaging detects focal cerebral lesions in patients with the Sjögren syndrome and central nervous system involvement, including patients with psychiatric and cognitive dysfunction alone.

Adult↗

Periodate and recombinant interleukin-2-activated autologous leukocytes can induce regression of metastases of renal cancer.

We present the results of a pilot study that determined the effects of both intermittent injections of periodate and recombinant interleukin-2 (rIL-2)-activated leukocytes and continuous infusions of low doses of rIL-2 on metastases of nine patients with stage IV renal cancer. Four patients experienced regressions, two patients stabilized, and only three patients did not respond. The responses of individual lesions in six patients were heterogeneous with regard to both the degree (ranging from cessation of growth to regression to undetectability) and the duration (ranging from less than 3 to up to 8 months). Survival times from the time of diagnosis and from the time of start of the protocol treatment ranged from 12 to 20 months and 6 to 12 months, respectively, for three patients who expired and from 10+ to 28+ months and 6+ to 12+ months, respectively, for six patients who are alive. Only one patient experienced a grade 4 toxicity (transient renal failure requiring hemodialysis). All other toxicities (grades 1-3) were easily controlled and resolved completely after 7 days. This pilot study deserves clinical testing on a larger scale, since it combines regression inductions in a hitherto treatment-resistant cancer with little complicating toxicity.

Adult↗

Effect of desmethylimipramine on norepinephrine content and plasticity of kitten visual cortex.

Because norepinephrine (NE) reuptake inhibitors have been reported to block 6-hydroxydopamine (6-OHDA) induced NE depletion, we wondered whether a reuptake inhibitor would block 6-OHDA's effects on visual cortical plasticity. We found, however, that desmethylimipramine (DMI) did not reduce 6-OHDA-induced NE depletion at 6-OHDA doses sufficient to prevent the effects of monocular deprivation. We also found that DMI itself induced transient NE depletion. We used this last result to further examine the NE hypothesis of depletion. In contrast to 6-OHDA-induced NE depletion, DMI-induced NE depletion was not accompanied by changes in visual cortical plasticity.

Animals↗

Adoptive immunotherapy for stage IV renal cell carcinoma: a novel protocol utilizing periodate and interleukin-2-activated autologous leukocytes and continuous infusions of low-dose interleukin-2.

In a pilot study involving 13 patients with advanced stage IV renal cell carcinoma, anti-tumor effects and toxicity of a novel form of adoptive immunotherapy were determined. The protocol utilizes infusions of autologous mononuclear leukocytes treated with the oxidizing mitogen sodium periodate (IO4-) and cultured in medium containing human recombinant interleukin-2 (IL-2), and continuous infusions of low-dose IL-2 (mean +/- SD dose = 39.5 +/- 8.6 X 10(3) U/kg/24 hours). Leukocytes (5 to 10 X 10(9] were removed by leukapheresis three times per week, mononuclear cells were separated, activated with IO4- and cultured in medium containing IL-2 (500 U/ml) for 48 to 72 hours. The cells were re-infused following the next leukapheresis procedure. IL-2 was administered five days per week. Treatment was continued for two three-week cycles. An increase in peripheral blood mononuclear cells bearing the natural killer cell (NK) surface marker, Leu 11, an increase in NK- and antibody-dependent cell-mediated cytotoxicity, and a slight increase in spontaneous cytotoxicity for non-NK targets were noted. Regressions (more than 50 percent decrease in tumor mass) of pulmonary, liver, bone, or soft tissue metastases were induced in six patients. Severe fluid retention did not develop in any patient and no patient required treatment in the intensive care unit. Five of the patients who showed a response have experienced a relapse at 5.2 +/- 1.0 (mean +/- SD) months. These observations indicate that IO4-/IL-2-activated killer cells plus continuous infusions of low-dose IL-2 can result in regression of metastatic renal cell carcinoma.

Adult↗

Timing of 6-hydroxydopamine administration influences its effects on visual cortical plasticity.

We recorded from the visual cortex of 4 groups of monocularly deprived kittens. Three groups were treated with intraventricular 6-hydroxydopamine (6-OHDA) at different times relative to monocular deprivation (MD). One group received only vehicle solution and MD. 6-OHDA caused the greatest decrease in plasticity in the kittens receiving 6-OHDA throughout the deprivation period; that is, these kittens were the least affected by MD. 6-OHDA caused a smaller decrease in plasticity in kittens receiving 6-OHDA just prior to eyelid suture and a still smaller decrease in kittens waiting a week between 6-OHDA treatment and eyelid suture. The kittens in all groups receiving 6-OHDA were equally depleted of norepinephrine (NE). We conclude that 6-OHDA decreases plasticity in the visual cortex; however, the time course of this decrease is better related to the time course of the 6-OHDA treatment than to the time course of NE depletion.

Age Factors↗

Follow-up of outpatient referrals from a psychiatric emergency room.

This article reports on the findings of a follow-up study of a cohort of 114 patients who were evaluated at a psychiatric emergency room and were referred to community mental health and substance abuse agencies. Two-thirds subsequently made contact with these agencies, but fewer made contact with the agency to which they were specifically referred. Few kept their scheduled appointment. Prior experience with an agency, as was a client's diagnosis, were related to agency contact. Considerations for social workers to increase patients' ability to complete referrals for treatment are addressed.

Adult↗