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Biomedical subjects

T Norman

Publications and source records attributed to T Norman.

At least 19 recordsLinked to original sources
PubMed2005

Pharmacokinetics of imipenem-cilastatin following intravenous administration in healthy adult horses.

In two studies, six healthy adult horses were given imipenem-cilastatin by slow intravenous (i.v.) infusion at an imipenem dosage of 10 mg/kg (study 1) and 20 mg/kg (study 2). The same horses were used in each dosage schedule, with a 2-week washout period between studies. In each dosage group, serial blood and synovial fluid samples were collected for 6 h after completion of the infusion. HPLC was used to determine the imipenem concentration in all samples. Imipenem was well tolerated by all horses at both dosages; no adverse effects were noted during the study period or during the 24-hour postinfusion observation period. The pharmacokinetic profiles of imipenem in the plasma and synovial fluid indicate that an imipenem dosage of 10-20 mg/kg by slow i.v. infusion q6h (every 6 h) is appropriate for most susceptible pathogens.

Animals↗
PubMed2004

Cefotaxime kinetics in plasma and synovial fluid following intravenous administration in horses.

Cefotaxime powder was diluted with sterile water to a concentration of 100 mg/mL. The volume of solution was adjusted for each experimental horse to provide a total dose of 15, 20, and 25 mg/kg and was administered by infusion through a jugular vein catheter over a 10-min period. All three doses were administered to each of the six experimental horses at three different times. Cefotaxime concentrations in plasma and synovial fluid samples were measured by high-performance liquid chromatography (HPLC). Standard compartmental analysis techniques and the WinSAAM modeling program were used to determine standard pharmacokinetic parameters for cefotaxime. The plasma and synovial fluid data from the five horses administered the 25 mg/kg dose was analyzed. Plasma cefotaxime concentrations appeared to be linearly related to dose infused and declined in parallel, suggesting linear drug kinetics. Moreover, cefotaxime concentrations declined monotonically suggesting that its disposition kinetics could essentially be described by a one-compartment model rather than the fact that sampling occurred after the infusion was discontinued. Maximum concentration of cefotaxime in plasma occurred immediately after cessation of the infusion. Minimum inhibitory concentrations were determined for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, common isolates from septic arthritis in horses. Based on our pharmacokinetic data, a regimen of 25 mg/kg administered i.v. every 6 h appears appropriate for susceptible joint infections in adult horses.

Animals↗
PubMed2003

In vitro performance of intramedullary cement restrictors in total hip arthroplasty.

Contemporary cementing techniques in total hip arthroplasty include the use of a cement restrictor to occlude the intramedullary canal. As there are many different designs currently available it was the aim of our study to compare the stability of eight different systems. We investigated the displacement and the ability to occlude the femur of these cement restrictors during standardised cementing of artificial and fresh frozen femora. The maximal intramedullary pressures and the displacement of the plugs were continuously recorded and statistically evaluated. The results revealed significant differences between the tested cement restrictors. The expandable REX Cement Stop and the Exeter Plug achieved the highest stability and the least cement leakage. The more rigid designs (Palacos Plug, BUCK, Universal) in contrast showed inferior performance. Our biomechanical study emphasises the importance of cement restrictor selection, which can have a crucial influence on the fixation of a cemented total hip replacement.

Aged↗
PubMed1999

The evaluation of depression in inpatients with HIV disease.

OBJECTIVES: The aim of this paper is: to compare the utility of four approaches to the diagnosis of depression in patients with human immunodeficiency virus (HIV) disease; to examine the utility of four rating scales to assess the presence and severity of depression; and to devise a set of substitutive criteria that would be appropriate in patients with HIV disease. METHOD: A group of inpatients was assessed using standard clinical interview. Patients found to have major depression using DSM-III-R (aetiological) criteria were assessed using inclusive, substitutive and exclusive criteria for the diagnosis of depression. Severity was assessed using the Hamilton Depression Rating Scale (HDRS), the Montgomery Asberg Depression Rating Scale (MADRS), the Beck Depression Inventory (BDI), and the Centre for Epidemiological Studies Depression Rating Scale (CES-D). A group of control patients were matched for age and severity of HIV illness. RESULTS: Seventeen patients met DSM-III-R (aetiological criteria) for major depression. All were male; they had a mean age of 40.6 years and one-third had acquired immune deficiency syndrome (AIDS). Using alternative approaches to the diagnosis of depression, up to five additional 'depressed' patients were identified ('false positives'). All 17 patients meeting the DSM-III-R criteria also met the substitutive and exclusive criteria but only 15 exclusive criteria. Of the 17 controls (not meeting DSM-III-R criteria), two met substitutive, five inclusive and one exclusive criteria for depression. The mean (+/- SD) scores for the patients and controls were significantly different on all four rating scales. Analysis of individual items on the rating scales revealed that a number did not show significant differences between the depressed and nondepressed groups: on the MADRS the items lassitude and inner tension; on the HDRS the three items depicting anxiety symptoms, loss of libido, hypochondriasis, loss of weight, and maintenance of insight; on the BDI a sense of being punished, disappointed in self, being self-critical, a feeling of looking unattractive, fatigue, weight loss, worried about health and loss of libido; on the CES-D I felt just as good as others, hopeful, talk less, people unfriendly and felt people dislike me. CONCLUSIONS: The aetiological approach used by clinicians familiar with the features of HIV disease, was found to be useful. All four rating scales differentiated equally well between depressed and non-depressed groups.

Adult↗
PubMed1998

Platelet paroxetine binding in post-traumatic stress disorder.

Sixty-two subjects, 45 with post-traumatic stress disorder (PTSD) and 17 healthy control subjects, were examined in a study of serotonin function measured by [3H]paroxetine binding to platelet membranes. Subjects were selected from male combat exposed veterans. The mean (+/- S.D.) Kd was 0.078 +/- 0.045 nM for the PTSD patient group and 0.064 +/- 0.037 nM for the control group. The mean Bmax was 934 + 238 fmol/mg protein for the PTSD patient group and 1011 +/- 363 fmol/mg protein for the control group. There was no significant difference between the groups for either Kd or Bmax before or after controlling for season of sampling. There were no significant differences between subjects with current PTSD and those with PTSD in the past, or between PTSD subjects with or without concurrent major depressive disorder. This study finds no relationship between PTSD, major depressive disorder and peripheral serotonin function measured by [3H]paroxetine binding to blood platelets.

Adult↗
PubMed1998

Negative symptoms, depression, and parkinsonian symptoms in chronic, hospitalised schizophrenic patients.

BACKGROUND: Negative symptoms of schizophrenia are often confounded by overlapping depressive and parkinsonian symptoms. The role of medication as an aetiological factor in the development of these symptoms is an important issue for prevention and treatment. METHODS: A total of 45 inpatients in chronic wards who met RDC criteria for schizophrenia were assessed with the Hamilton depression rating scale (HDRS) and negative symptom rating scale (NSRS) and the targeting abnormal kinetic effect scale (TAKE). RESULTS: No significant correlation was found between the total scores on the vegetative superfactor of the HDRS and the NSRS. Duration of neuroleptic treatment was positively correlated with depressive symptoms (r=0.299, P < 0.05) and negative symptoms (r=0.443, P < 0.001). Dose of antipsychotic was also correlated positively with negative symptoms (r=0.260, P < 0.05). Age was negatively correlated with depressive symptoms as assessed by the HDRS (r=0.306, P <0.05). CONCLUSION: The data suggest that depressive and negative symptoms can be separated in chronic schizophrenia, while pointing to a possible role of antipsychotic medication in the aetiology. LIMITATIONS: The study was conducted in a small chronically hospitalised population treated with relatively high doses of antipsychotics. It is not clear that the results obtained here would be applicable to an acute patient population.

Adult↗
PubMed1997

Aggressive behaviour and platelet 3H-paroxetine binding in schizophrenia.

Forty schizophrenic patients were included in a study of the relationship between serotonin function as measured by 3H-paroxetine binding to platelet membranes and aggressive behaviour. Patients classified as either aggressive or non-aggressive were paired by age, sex and duration of illness. 3H-Paroxetine binding variations were avoided by taking samples for each pair between 09:00 and 11:00 h, within 4 days of each other, and by assaying pair of samples together. The mean Kd for the aggressive group was 0.193 +/- 0.126 nM and the mean Kd for the non-aggressive group was 0.176 +/- 0.164 nM. The mean Bmax for the aggressive group was 1451 +/- 386 fmol/mg protein while the mean for the non-aggressive group was 1549 +/- 375 fmol/mg protein. There was no significant difference between the groups for either parameter, Kd or Bmax. There were no significant correlations between psychopathology rating including positive and negative symptoms, depression, suicidal thoughts, impulse control, as well as both past and present history of aggression, hostility and irritability traits, psychopathic deviance and either Bmax and Kd. This study finds no relationship between aggressive behaviour and peripheral serotonin function as measured by 3H-paroxetine binding to platelet membranes.

Adult↗
PubMed1992

Patient satisfaction with pharmacologic erection program.

One hundred seventy-two patients on a pharmacologic erection program for male erectile dysfunction were sent a detailed questionnaire regarding their satisfaction using intracorporeal injection with vasoactive drugs. Sixty-seven percent of patients responded. Eighty-five percent of respondents said their sex life was improved. Eighty-eight percent would recommend penile self-injection to a friend whose complaint is impotence. Despite this, 49 percent of respondents were no longer using self-injections. The results from our detailed questionnaire suggest that the majority of the patients are quite satisfied with the erections achieved with intracorporeal injection of vasoactive drugs. The high dropout rate associated with such a program may be due to reasons other than the quality of erection achieved and sexual satisfaction derived from pharmacologic erections.

Adult↗
PubMed1992

Relationship of symptomatology of schizophrenia and tardive dyskinesia.

The role of drug factors and patient factors in the development of tardive dyskinesia (TD) was examined in 31 TD patients and 31 non-TD patients matched by age and sex. TD patients achieved significantly lower total scores on the anxiety-depression factor of Brief Psychiatric Rating Scale (BPRS) (5.2 +/- 1.4 vs. 6.5 +/- 2.2; less than P) and significantly higher total scores on the activation factor (6.4 +/- 2.2 vs. 5.3 +/- 2.5; less than P). The finding that TD patients were less depressed may be explained by a hypermonoaminergic state developing in TD. Based on the findings of this study it is suggested that catatonic schizophrenic patients are more vulnerable to the development of TD.

Adolescent↗
PubMed1991

Fenfluramine augmentation of clomipramine treatment of obsessive compulsive disorder.

Recently, much research interest has been directed to demonstrating a possible biological basis to obsessive compulsive disorder. In particular, dysregulation in brain serotonin is suggested to be important. Two cases are described in which fenfluramine, a presynaptic 5 HT-releasing agent and 5HT-reuptake inhibitor was used to augment clomipramine treatment for OCD.

Adult↗
PubMed1989

Reproductive hormones in menstrual blood.

Menstrual and peripheral blood samples were collected from 19 regularly cycling women on days 1-3 of the menstrual cycle. Menstrual samples were collected with a soft silicone rubber menstrual cup. Hematocrit, PRL, LH, FSH, estradiol (E2), and progesterone (P4) were measured in all samples. Validation studies were carried out for RIAs of PRL, LH, and FSH in menstrual plasma. The menstrual plasma PRL level was significantly higher than its peripheral blood level on day 1 (63.3 +/- 14.7 and 12.1 +/- 2.9 micrograms/L, respectively; t = 3.331; P less than 0.01), and menstrual PRL was significantly higher on day 1 than on day 2 (t = 3.340; P less than 0.01). There was a strong negative correlation between log menstrual PRL concentration and time of onset of menstruation (r = -0.596; P less than 0.01). Menstrual plasma FSH levels were significantly lower than peripheral levels on each of days 1-3 (day 1:t = 4.787; P less than 0.001), and there was a significant positive correlation between menstrual and peripheral levels (r = 0.607; P less than 0.01). By contrast, menstrual plasma LH was significantly higher than the peripheral level on days 1 and 2 (day 1:t = 3.105; day 2:t = 3.180; P less than 0.01), with no correlation between menstrual and peripheral levels. Menstrual E2 was slightly lower than and significantly positively correlated with peripheral E2 (r = 0.646; P less than 0.01). Menstrual P4 was lower than but showed no correlation with peripheral levels. As expected, the menstrual blood hematocrit was less than 0.20 and highly significantly lower than that of peripheral venous blood. These results suggest that PRL is released in substantial amounts from secretory endometrium into the menstrual flow during the first day of menstrual breakdown. LH may also be released in small amounts from menstrual endometrium, while menstrual FSH, E2, and P4 probably arise entirely from the peripheral circulation.

Adult↗
PubMed1987

Single oral dose pharmacokinetics of tiapride in patients with Huntington's disease.

The pharmacokinetic properties of a single oral dose of 100 mg of tiapride were studied in six patients with Huntington's disease. The results for five patients were consistent with a two compartment open model. Peak plasma concentrations were observed within 2 h following drug administration with a mean value of 0.92 micrograms/ml being recorded. The drug was rapidly eliminated as unmetabolised tiapride in the urine, 51% of the dose was recovered in 24 h. The plasma elimination half-life was 5.3 h and the average apparent plasma clearance was 16.6 l/h.

Administration, Oral↗
PubMed1984

A study of the dexamethasone suppression test in hospitalized depressed patients.

90 patients with a primary depressive illness, admitted consecutively to one psychiatric ward were studied. All patients had the dexamethasone suppression test (DST) done before initial treatment. First treatment response was correlated with the DST results. The non-suppressors, as a group, improved with treatment better than the suppressors. However, unlike in previous studies, no relationship was found between non-suppression and poor response to antidepressant medication.

Adjustment Disorders↗
PubMed1983

The pharmacokinetics of mianserin in elderly depressed patients.

The pharmacokinetics of mianserin were examined in eight elderly depressed patients following a single oral dose of 60 mg. Plasma concentrations were measured by gas chromatography/mass spectrometry and the data analyzed using a two-compartment open model. Mean (+/- SD) estimates were: absorption half-life 0.8 +/- 1.0h, peak concentration 117 +/- 23 micrograms/l, peak time 2.2 +/- 1.3h, distribution half-life 3.4 +/- 1.2h, elimination half-life 33 +/- 15h, apparent volume of distribution 20.2 +/- 7.9 1/kg, and oral clearance 0.49 +/- 0.21 l/kg/h. These parameters were not significantly different from those found in healthy volunteers. The absorption lag time (0.6 +/- 0.2h) and area under the curve (2009 +/- 566 micrograms/l/h) were significantly different in the elderly. The clinical implications of these differences for the treatment of elderly depressed patients are discussed.

Age Factors↗
PubMed1982

Ligand binding and platelet uptake studies of loxapine, amoxapine and their 8-hydroxylated derivatives.

Loxapine, amoxapine and their 8-hydroxylated derivatives were studied by means of [3H]imipramine binding to rat cortical membranes, [3H]spiperone binding to rat striatal membranes, and the inhibition of serotonin uptake by human platelets. As inhibitors of [3H]imipramine binding: amoxapine greater than hydroxyamoxapine greater than loxapine = hydroxyloxapine; as inhibitors of platelet serotonin uptake: hydroxyamoxapine greater than amoxapine greater than hydroxyloxapine greater than loxapine; and as inhibitors of [3H]spiperone binding: loxapine greater than amoxapine greater than hydroxyamoxapine greater than hydroxyloxapine. The antipsychotic properties of loxapine and amoxapine were supported by the binding results, which also indicated the probable antipsychotic activities of the metabolites. All 4 compounds may possess dual action of antidepressant effect as well as antipsychotic effect.

Amoxapine↗