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Biomedical subjects

D Hawkins

Publications and source records attributed to D Hawkins.

At least 91 records · Page 5Linked to original sources
PubMed1990

A method for determining lower extremity muscle-tendon lengths during flexion/extension movements.

A study was conducted to examine the relationship between muscle-tendon lengths of 16 lower extremity muscles and the flexion angle(s) of the joint(s) they cross. Anthropometric data from six subjects were obtained. Various lower extremity joint flexion angle combinations were simulated for each subject using computer software. For each simulated lower extremity position, muscle origin and insertion locations were determined based on averaged cadaveric origin/insertion information and individual anthropometric parameters. Corresponding muscle-tendon lengths were computed and normalized to segment lengths. Regression equations were derived which allow normalized muscle-tendon lengths to be estimated from known joint flexion angles. The regression equations obtained for biarticular muscles fit the data quite well giving correlation coefficients greater than 0.92. The correlation coefficients for the equations describing normalized single joint muscle-tendon lengths range from 0.77 to 0.97. The equations were then validated by comparing predicted lengths to those reported by previous investigations. Confirming the utility of the equations, the comparisons were excellent for both uniarticular and biarticular muscles. Used in conjunction with velocity data (obtained by differentiating the length data) and electromyogram recordings, these equations enable a detailed analysis of muscle function.

Adult↗
PubMed1990

Neuropsychological and psychiatric changes following treatment of ARC patients with zidovudine.

Six homosexual men with a diagnosis of acquired immunodeficiency syndrome (AIDS)-related complex (ARC- CDC IVA/C2) were assessed with a series of neuropsychological and psychiatric tests prior to commencing treatment with zidovudine and again after 5-6 months. Significant improvements were seen in cognitive functioning, mental state and physical health at the second assessment.

AIDS-Related Complex↗
PubMed1989

Clinics for HIV-positive patients.

There are marked regional differences in the organisation of services for HIV-positive patients. A successful method for one London based specialist centre is a combination of walk-in clinics, organised outpatients and day ward care.

Day Care, Medical↗
PubMed1989

Zidovudine treatment of patients with acquired immune deficiency syndrome and acquired immune deficiency syndrome-related complex: St Stephen's Hospital experience.

Zidovudine was used in an open uncontrolled study for treatment of 145 human immunodeficiency virus (HIV) patients, 102 with acquired immune deficiency syndrome (AIDS) and 43 with symptomatic HIV disease (acquired immune deficiency syndrome related-complex, ARC). The mean period of follow-up was 6 +/- 2.5 months. The median survival time of AIDS patients on zidovudine was 4.5 times longer when compared to a historical zidovudine untreated AIDS group (1657 vs. 370 days). This should be interpreted with reserve regarding improvements in treatment of all aspects of HIV infection and heightened awareness of AIDS which may have led to earlier diagnosis in the zidovudine treated groups. Pneumocystis carinii pneumonia (PCP) was very rarely a cause of death in zidovudine-treated patients (4.8%), while it was responsible for the death in 46.2% of historical controls (P less than 0.001). Extensive Kaposi's sarcoma was equally the cause of death in treated as well as in historical patients. Median T4 cell counts increased on zidovudine reaching a peak at the end of the fourth month of therapy in the ARC group and at the end of the first month in the AIDS group with a subsequent fall. Sixty per cent (53 of 87) patients were p24 viral antigen positive at the start of treatment and 19% of them had a fall of more than 50% in antigen level in three months while 32% became antigen negative within 2.5 months. Survival in patients where the antigen disappeared or in whom there was a major (greater than 50%) fall in antigen level was significantly higher than in those for whom there was no change in antigen level or in whom the antigen was negative at the start of the study (P less than 0.05). Forty-seven of the 145 zidovudine treated patients needed to be transfused because of anaemia. The mortality was significantly higher in this group of patients, particularly in those transfused prior to zidovudine therapy. Neutropenia occurred in four subjects. Platelets rose after the start of zidovudine but subsequently fell to thrombocytopenic levels in eight patients.

AIDS-Related Complex↗
PubMed1989

Oesophageal symptoms, their causes, treatment, and prognosis in patients with the acquired immunodeficiency syndrome.

In a prospective study of 154 AIDS patients, 48 (31%) complained of pain on swallowing both liquids and solids and 32 (21%) of these also had dysphagia. While candidiasis was the most common cause of symptoms (26 patients), discrete ulceration of the oesophagus occurred in 12 instances in 10 patients (four cytomegalovirus, four herpes simplex virus, three aphthous ulcer, one peptic ulcer). One patient had a diffuse oesophagitis caused by Mycobacterium avium intracellulare. No cause was found for the oesophageal symptoms in four patients. Kaposi's sarcoma (KS) was found in seven patients associated with other pathology in four. All 26 patients with oesophageal candidiasis only, also had oral involvement. All the patients with herpes simplex virus (four) and aphthous ulcers (three) had obvious perioral involvement. Three of the four patients with cytomegalovirus ulceration had evidence of disease elsewhere (colon or retina). All patients with Kaposi's sarcoma lesions had skin and buccal cavity involvement. The cause of oesophageal disease was usually obvious at endoscopy. The appearance of candidiasis was typical and the various ulcerating lesions also had different macroscopic configurations. Cytomegalovirus infection produced deep linear ulcers in the distal oesophagus, herpes simplex oesophagitis is similar in appearance to the typical perioral lesions of fluid filled vesicles. Diagnostic radiology was not helpful in most patients. In nine of 17 patients with candidiasis, the barium swallow examination performed within 24 hours of presentation was normal. In only three of seven patients with oesophageal ulceration (three cytomegalovirus, two herpes simplex virus, one aphthous, one peptic) was there evidence of an abnormality. Treatment produces symptomatic relief. All patients with candidiasis responded to ketoconazole, the four with herpes simplex virus to acyclovir and one of three with aphthous ulceration had a dramatic response to thalidomide. The three patients with cytomegalovirus infection who were treated with foscarnet had a prolonged remission of symptoms. The overall prognosis of patients with oesophageal symptoms is poor, with an average survival time from a definitive diagnosis of five months (range one to 13).

Acquired Immunodeficiency Syndrome↗
PubMed1989

The effects of high extracellular Ca2+ and Mg2+ concentrations on the levels of inositol 1,3,4,5-tetrakisphosphate in bovine parathyroid cells.

We examined the effects of calcium (Ca2+), magnesium (Mg2+), and fluoride ion (F-) on inositol phosphate accumulation in bovine parathyroid cells prelabeled with [3H] inositol to determine whether these agents might modulate cytosolic Ca2+ through accumulation of intracellular inositol 1,3,4,5-tetrakisphosphate (IP4), which has been postulated to be a mediator of the influx of extracellular Ca2+. Both Ca2+ and Mg2+ produced dose-dependent increases in IP4 in the presence of Li+, with maximal 19- and 4-fold increases with 5.0 mM Ca2+ and 20 mM Mg2+, respectively. A 50% rise in IP4 was evident within 1 min in response to 5.0 mM Ca2+. In the absence of Li+, a 2-fold increase in IP4 was seen with 5.0 mM Ca2+ only after 15 min. Fluoride ion generated a dose-dependent increase in IP4, with a 48% rise at 10 mM F-, presumably by activating phospholipase-C through a guanine nucleotide regulatory (G) protein-dependent process. We conclude that inositol 1,4,5-trisphosphate generated in response to high extracellular Ca2+ and Mg2+ concentrations can be converted to IP4 in parathyroid cells. The slow kinetics for the increase in IP4 with high Ca2+ in the absence of Li+, however, do not support a role for IP4 in the early phase of the sustained increase in cytosolic Ca2+ produced by high extracellular Ca2+ concentrations.

Animals↗
PubMed1989

The efficacy and toxicity of azidothymidine (AZT) in the treatment of patients with AIDS and AIDS-related complex (ARC): an open uncontrolled treatment study.

The efficacy and toxicity of oral azidothymidine has been studied in 145 patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC). The median survival time of AIDS patients on azidothymidine was 4.5 times higher when compared to a historical AIDS group who had not received the drug. This result must be interpreted with caution because of changes in treatment of HIV infection and growing awareness of AIDS which may have led to earlier diagnosis in the group treated with azidothymidine. The mortality was significantly higher in those patients who received transfusions and was particularly high in those who were transfused before azidothymidine. There was a significant difference in the occurrence of opportunistic infections in the patients who received transfusions compared with those who did not. AIDS patients treated immediately after an episode of Pneumocystis carinii pneumonia survived significantly longer than those in whom treatment was delayed for three months or more, and longer than those who were treated with azidothymidine because of another opportunistic infection or Kaposi's sarcoma. The T4 cell median counts increased in patients treated with azidothymidine reaching a peak at the end of the fourth month of treatment in the ARC group and at the end of the first month in the AIDS group with a subsequent fall in both groups. Sixty per cent of patients were p24 viral antigen positive at the start of treatment and 19 per cent of these patients had a fall of more than 50 per cent in antigen level while 32 per cent became antigen negative following treatment with azidothymidine. The mortality in the patients where the antigen disappeared or in whom there was a major fall of more than 50 per cent in antigen level was significantly less than in those where there was no change in antigen level. Twenty-nine patients were treated with azidothymidine because of skin Kaposi's sarcoma and in 17 tumour regressed or was stable. Thirty-two per cent of patients treated with azidothymidine became anaemic. Neutropenia occurred in 3 per cent of patients. Platelets increased initially after treatment but subsequently fell to thrombocytopenic levels in eight patients. Nine of 12 patients with thrombocytopenia before azidothymidine was commenced responded with an increased platelet count.

AIDS-Related Complex↗
PubMed1989

Protective HLA-DR phenotypes in rheumatoid arthritis.

In a study of HLA-DR phenotypes in patients with rheumatoid arthritis (RA) and controls from the Saskatoon area and in Newfoundland, we found that certain phenotypes occurred more frequently in the patients than in healthy controls in both populations ("increased risk phenotypes"). The reverse was also true: certain phenotypes were reduced or excluded from patients with RA compared with controls. Three increased risk phenotypes with twice the expected frequencies or more were HLA-DR1,DR4; DR4 and DR4,DR5. Four "protective" phenotypes with half or less the expected frequencies were HLA-DR1, DR5; DR2; DR2,DR3 and DR3,DR7. We speculate that at least for the DR3,DR7 phenotype, the protective effect may be due to a hybrid DQw2 molecule.

Arthritis, Rheumatoid↗
PubMed1988

Expression of human adenosine deaminase in murine hematopoietic cells.

Multiple replication-defective retrovirus vectors were tested for their ability to transfer and express human adenosine deaminase in vitro and in vivo in a mouse bone marrow transplantation model. High-titer virus production was obtained from vectors by using both a retrovirus long terminal repeat promoter and internal transcriptional units with human c-fos and herpes virus thymidine kinase promoters. After infection of primary murine bone marrow with one of these vectors, human adenosine deaminase was detected in 60 to 85% of spleen colony-forming units and in the blood of 14 of 14 syngeneic marrow transplant recipients. This system offers the opportunity to assess methods for increasing efficiency of gene transfer, for regulation of expression of foreign genes in hematopoietic progenitors, and for long-term measurement of the stability of expression in these cells.

Adenosine Deaminase↗
PubMed1988

Homosexual and heterosexual sex-role orientation on six sex-role scales.

A comparison was made of the sex roles of homosexual and heterosexual men and women on the Bem Sex Role Inventory, Personality Attributes Questionnaire, Personality Research Form Androgyny Scale, Adjective Checklist Masculinity and Femininity Scales, Extended Personality Attributes Questionnaire and Undesirable Characteristics Scale. The results indicated that homosexuals and heterosexuals differ in their response to different aspects of sex roles. The most consistent difference was the greater femininity of male homosexuals in respect to male heterosexuals. Other differences were scale-specific and the low interscale comparability indicated such scales should not be used interchangeably. Differences between results of studies comparing sex roles of the homosexuals and heterosexuals appear attributable to sample heterogeneity and distinctions between sex-role scales.

Adult↗
PubMed1984

Development and evaluation of a selective medium for an anaerobe associated with non-gonococcal urethritis.

The purpose of the study was to develop a selective medium for the isolation of an anaerobe that is associated with non-gonococcal urethritis. This was achieved by determining the sensitivity of 64 strains of the NGU-associated anaerobe to 20 antibiotics and three dyes by the disc-diffusion method. Then the MIC of eight of these antimicrobial agents for ten of the strains was determined by a tube dilution method. The results led to the formulation of a selective agar medium based on the incorporation of polymyxin (0.15 IU/ml), trimethoprim (10 micrograms/ml), vancomycin (10 micrograms/ml) and methyl green (32 micrograms/ml). This medium supported growth of the NGU-associated anaerobe but did not support growth of the other anaerobes tested. The selective nature of the medium made possible the recovery of the NGU-associated anaerobe from 13 of the 25 specimens from men with NGU, compared with isolation from only 8 of these men when using a non-selective medium.

Anti-Bacterial Agents↗
PubMed1982

Predictive value of radionuclide joint scintigrams.

Twenty-two patients with normal or "noninflammatory" 99mtechnetium-labeled polyphosphate (TPP) peripheral joint scintigrams taken between 1974 and 1976 were reevaluated clinically. Retrospective chart review revealed that all initially had persistent polyarthralgia of more than 3 months duration. At followup, a mean of 3.6 years later, none had evidence of inflammatory joint disease, although 1 patient had systemic lupus erythematosus and 2 had polymyalgia rheumatica. A noninflammatory joint scintigram as part of a thorough rheumatologic evaluation may be a useful procedure in excluding inflammatory joint disease in selected patients with chronic persistent polyarthralgia.

Adult↗