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Biomedical subjects

S Kennedy

Publications and source records attributed to S Kennedy.

At least 307 records · Page 17Linked to original sources

Experimental intrauterine inoculation of pregnant ewes with ureaplasmas.

The pregnancies of 13 ewes which were inoculated intrauterine with one of two strains of ovine ureaplasmas resulted in 9 normal and 3 abnormal births, and one ewe was found to be no longer pregnant on postmortem examination. Vaginal ureaplasma infection was detected in the majority of ewes only after lambing. Of the 12 ewes examined at postmortem, ureaplasmas were isolated from the uterus of 5 out of the 6 necropsied up to 21 days post-partum. The vulvar/preputial areas of the majority of lambs that survived were infected with ureaplasmas for the duration of the experiment, but infections of the nasal cavity and eye areas, detected at birth in 4 lambs, were resolved within 8 days post-partum. The only pathological effects detected that could possibly be attributed to ureaplasma infection were a placentitis in an ewe that aborted, and the resorption of the foetus in another.

Animals↗

Affective disturbance in eating disorders.

Thirty-three bulimic and 14 restrictive anorexics were compared on DSM-III diagnoses of affective and anxiety disorders, observer-rated and self-rated measures of depression and anxiety, and family history. A subgroup of 18 eating disorder subjects was administered the dexamethasone suppression test. The same 18 subjects were compared to 13 subjects with affective disorder on the Schedule for Affective Disorders and Schizophrenia. It was found that a large group with bulimia and restrictive anorexia nervosa was subject to a depressive disorder. Thirty-eight percent of the sample fulfilled criteria for a major depressive episode. The dysphoric experience seemed as intense in the bulimic and restricter group. There was a high incidence of dexamethasone nonsuppression (55%), which was found to be related to various measures of depression. Bulimics and restricters differed in their family history of affective disorder. While 61% of bulimics had a positive history of depression, this was found in only 23% of restricters (p less than .03).

Adolescent↗

Density-dependence of maximal expiratory flow and its correlation with small airway disease in smokers.

Density-dependence of maximal expiratory flow was measured in 110 patients prior to resection for peripheral coin lesions. The resected lung or lobe was examined morphologically and graded for emphysema, membranous bronchiolitis, and respiratory bronchiolitis. Density dependence did not decrease with increasing airway obstruction, and there was no relationship between density-dependence and peripheral airway abnormality or emphysema in the group as a whole. When patients were arbitrarily divided into those with forced expiratory volume in one second (FEV1) greater than 80% predicted (n = 80) and FEV1 less than 80% predicted (n = 30), density-dependence correlated significantly and negatively with membranous bronchiolitis in those with FEV1 greater than 80% predicted and significantly but positively in those with more advanced airway obstruction. We conclude that density-dependence of maximal expiratory flow is not an accurate predictor of peripheral airway abnormality in patients with mild to moderate air-flow obstruction.

Aged↗

The dexamethasone suppression test and suicidal patients.

The dexamethasone suppression test (DST) was used in an in-patient crisis unit to determine whether the test could identify suicidal patients who might benefit from tricyclic antidepressants. DST results, DSM-III diagnoses, and measures of symptom levels were obtained for 72 patients admitted for a 3-5 day period; 31 were non-suppressors. Abnormal DST results were not related to DSM-III diagnosis or to scores on measures of depression and symptom levels. Only three patients met DSM-III criteria for major depression with melancholia; 26 patients had a diagnosis of alcohol or substance abuse. The poor specificity of the DST in this patient population suggests that its routine use in such patients could be highly misleading.

Adolescent↗

Lymphadenopathy-associated virus antibodies and T cells in hemophiliacs treated with cryoprecipitate or concentrate.

Evidence for exposure to lymphadenopathy-associated virus (LAV) was investigated in 48 patients with hemophilia, 15 of whom had been treated exclusively with single-donor cryoprecipitate. The prevalence of antibodies to LAV in all patients was 53% in 1983 and 63% in 1984, while in patients treated only with cryoprecipitate, the prevalence was 31% in 1983 and 40% in 1984. Patients treated with any concentrate had a seroprevalence of 65% in 1983 and 77% in 1984. Seropositive patients were more likely to have a significant reduction in the ratio of helper to suppressor T cells, absolute numbers of helper T cells, and T cell function in vitro. Seven of 18 patients who were seronegative in 1983 had seroconverted by 1984. The relative risk of seroconversion for patients using any concentrate since 1981 compared with those using cryoprecipitate only was 3.9 (P = .04). Nevertheless, the rate of conversion in the latter group was 18% per year.

Acquired Immunodeficiency Syndrome↗

Akinesia and mutism following a methylphenidate challenge test.

A case of akinesia and mutism is described in a menopausal, depressed woman with onset following a mood challenge with 40 mg of methylphenidate taken orally over a 3-hour period. Various diagnoses are considered with preference given on clinical grounds to conversion disorder precipitated by drug-induced dysphoria. It is suggested that increased susceptibility to dysphoria may have been related to prior clomipramine administration and hypoestrogenism.

Adult↗

Experimental 3-nitro-4-hydroxyphenylarsonic acid toxicosis in pigs.

Five times the recommended dose of 3-nitro-4-hydroxyphenylarsonic acid (187.5 mg kg-1) induces a pathognomonic clinical syndrome in pigs. The main clinical features are not continually present but are inducible only by exercise. From day 11 on the experimental diet a nervous syndrome was inducible. This manifested as muscle tremors and clonic convulsive episodes. Paraparesis developed by day 22 and paraplegia by day 33. Liver arsenic levels plateaued at 5.4 +/- 1.3 mg kg-1. The experiment confirms field observations that 3-nitro produces a characteristic toxicological syndrome, which is distinct from that of arsanilic acid. It also confirms that 3-nitro has a higher absolute toxicity than arsanilic acid in pigs as well as a lower margin of safety.

Animals↗

The detection of small airways disease.

In order to investigate the relationship between pulmonary function and disease of the membranous and respiratory bronchioles, we studied 96 patients who required lobectomy for removal of a solitary pulmonary nodule. A subgroup of patients with forced expiratory volume in one second (FEV1) greater than 80% predicted were further analyzed to determine if abnormalities in tests designed to detect peripheral airways disease actually correlated with the pathology found in these airways. Analysis of the data shows that inflammation in both respiratory and membranous bronchioles, goblet cell metaplasia of the epithelium in membranous bronchioles, and decreasing muscle in the respiratory bronchioles are the pathologic features that are associated with deterioration of the FEV1. When the FEV1 is greater than 80% of the predicted value, inflammation of the respiratory bronchioles and fibrosis of both membranous and respiratory bronchioles increase with decreasing FEV1. Tests of specialized pulmonary function appear to correlate with epithelial pathologic parameters of membraneous bronchioles and inflammation and fibrosis of respiratory bronchioles. When patients with FEV1 greater than 80% predicted were subdivided according to the number of abnormal tests of small airways function, there was a significant increase in inflammation of the walls of respiratory bronchioles when 2 tests were abnormal and increases in both airway wall and intralumenal inflammatory cells as well as increased wall fibrosis when 3 tests were abnormal. We conclude that when the FEV1 is greater than 80% predicted, abnormalities in the tests for small airway disease reflect pathologic changes in the respiratory bronchioles.

Adolescent↗

Risk factors for depression in Canadians.

In a matched controlled study 72 Canadian patients with a major depressive episode were compared with non-depressed and never depressed orthopedic patients. Significantly more of the depressives had parental loss before 17 years of age, a poor marriage before the onset of depression and a family history of depression.

Adolescent↗

Differential diagnosis of emotional disorders that cause weight loss.

Recently, anorexia nervosa has received much attention in the scientific and lay press. As a result there is a danger that the other emotional disorders that can present with weight loss and vomiting will be overlooked. Case examples are presented for anorexia nervosa, conversion disorder, schizophrenia and depression. The presentation and treatment of these four disorders are compared.

Adolescent↗

Immunodot assay for determining the isotype and light chain type of murine monoclonal antibodies in unconcentrated hybridoma culture supernates.

We describe a procedure for determining immunoglobulin isotype and light chain class of murine monoclonal antibodies. Isotype and light chain-specific antibodies are immobilized as dots on a strip of nitrocellulose filter paper. The immobilized antibodies retain binding specificity, and the strips are used in a type of 'sandwich' immunoassay wherein murine monoclonal immunoglobulins bound to the appropriate anti-isotype dot are detected with a peroxidase-conjugated anti-mouse immunoglobulin reagent. The immunodot isotyping assay is specific and sensitive enough to detect mouse immunoglobulin present in ng/ml concentrations. It is as easy or easier to set up and perform than conventional isotyping techniques. It has the added advantages that it greatly conserves antisera reagents and can be performed on hybridoma culture supernates without the need to concentrate, expand, or purify them.

Animals↗

Determination of isosorbide dinitrate and its mononitrate metabolites in human plasma by high-performance liquid chromatography-thermal energy analysis.

An accurate and sensitive method for the simultaneous determination of isosorbide dinitrate and its 2- and 5-mononitrates in human plasma has been developed. Following extraction of 3.0 ml of plasma with 12.0 ml of dichloromethane-ethyl acetate (1:1) the extract is subjected to high-performance liquid chromatography employing a Zorbax NH2 column. The eluent stream is introduced into a thermal energy analyser, employing chemiluminescence as a specific means of detection. The minimum quantifiable level of the compound in plasma is 200 pg/ml allowing the quantitation of isosorbide dinitrate in human plasma following single oral administration. Nitroglycerin is employed as internal standard.

Chromatography, High Pressure Liquid↗

Experimental models for nutritional myopathy.

Nutritional myopathy is a disease affecting young ruminants. The aetiological factors and their relative importance in disease development have been explored. A theoretical model has been developed and tested experimentally. The disease can be produced consistently using a recently developed vitamin E- and selenium-deficient diet. Disease can occur spontaneously in animals maintained on this diet alone over an extended period. Alternatively, myopathy can be induced in deficient animals by feeding polyunsaturated fatty acids such as linoleic and linolenic acid from corn and linseed oils respectively. For ruminants the oils are protected to prevent hydrogenation in the rumen. Because a similar protective mechanism appears to occur with normal ruminant forages such as grass, and the development of disease is so similar to that occurring naturally, polyunsaturated fatty acids are thought to play a major role in the development of the disease. The experimental disease reproduces extensive and consistent lesions of skeletal and cardiac myopathy. Hyaline necrosis occurs in the skeletal muscle fibres of many major muscle groups. In the heart the accumulation of droplets of lipofuscin-like pigment in Purkinje fibres is the initial lesion, followed by necrosis of Purkinje fibres and peri-Purkinje fibrosis. The accumulating pigment has been characterized by fluorescence spectroscopy and histochemical techniques. The cardiac pathology results in detectable electrocardiographic abnormalities and sudden death.

Animals↗

Expression of a cloned Staphylococcus aureus alpha-hemolysin determinant in Bacillus subtilis and Staphylococcus aureus.

A DNA sequence encoding Staphylococcus aureus alpha-hemolysin, which had been previously cloned and mapped in Escherichia coli K-12, was introduced into Bacillus subtilis BD170 and several strains of S. aureus by using plasmid vectors, some of which could replicate in all three organisms. The determinant was cloned on a 3.3-kilobase pair DNA fragment into B. subtilis by using the vector plasmid pXZ105 to form the hybrid plasmid pXZ111. B. subtilis cells harboring pXZ111 produced large zones of alpha-hemolysis after 18 h of growth at 37 degrees C on rabbit blood agar plates, and alpha-hemolysin activity was detected in supernatants prepared from growing cultures of this strain. The alpha-hemolysin was apparently secreted across the B. subtilis cell envelope. Polypeptides of molecular weights 34,000 and 33,000 were precipitated with anti-alpha-hemolysin serum from lysates prepared from BD170 cells harboring pXZ111. A hybrid replicon which could replicate in both E. coli and S. aureus was constructed in E. coli by ligating a HindIII fragment encoding the replication functions and chloramphenicol resistance genes of S. aureus plasmid pCW59 to the pBR322 alpha-hemolysin hybrid plasmid pDU1150. The DNA of this plasmid, pDU1212, was prepared in E. coli and used to transform protoplasts prepared from a non-alpha-hemolytic, nonrestricting strain of S. aureus RN4220. Some of the transformants contained plasmids which had suffered extensive deletions. Some plasmids, however, were transformed intact into RN4220. Such plasmids were subsequently maintained in a stable manner. pDU1212 DNA was prepared from RN4220 and transformed into alpha-hemolytic S. aureus 8325-4 and two mutant derivatives defective in alpha-hemolysin synthesis. All three strains expressed alpha-hemolysin when harboring pDU1212.

Bacillus subtilis↗

Morphology of peripheral airways in current smokers and ex-smokers.

To investigate the effect of smoking status on pulmonary function and pathologic changes in the peripheral airways, we studied 97 patients who underwent thoracotomy for coin lesions. The patients were divided into 4 groups: nonsmokers (n = 9), current smokers (n = 51), and those who had ceased smoking for less than (n = 18) or more than (n = 19) 2 yr prior to surgery. We found that current smokers had evidence of air-flow obstruction with abnormal lung volumes when compared with nonsmokers. Ex-smokers had lung volumes similar to those of nonsmokers, but showed evidence of obstruction, with the FEV1/FVC between the values found for nonsmokers and current smokers. Examination of the small airways showed that the membranous bronchioles of current smokers and ex-smokers displayed only increased goblet cell metaplasia when compared with those in nonsmokers; the respiratory bronchioles of current and ex-smokers showed increases in intraluminal and airway wall inflammatory cells, wall fibrosis, and pigment deposition. We conclude that patients who currently smoke cigarettes have reduced lung function that is associated with abnormalities of airway structure. Although those who have stopped smoking have function that is closer to the nonsmoking group, there is no apparent difference in structural change between current and ex-smokers.

Aged↗