Biomedical subjects

T Verschoor

Publications and source records attributed to T Verschoor.

12 recordsLinked to original sources

PubMed2002

Constitutive active GTPases Rac and Cdc42 are associated with endoreplication in PAE cells.

The Rho-like guanine triphosphate (GTP)ases become activated by extracellular ligands and regulate a wide variety of biological processes, including cell motility, spreading of cells, cytoskeletal organisation and transcriptional activity. We studied the effect of expression of WtRac and Cdc42 and of their constitutive active V12 variants on cell cycle transition using the isopropylthiogalactoside (IPTG) inducible Rac and Cdc42 transfectants of porcine aortic endothelial (PAE) cells. Expression of V12Rac or V12Cdc42 resulted initially in an enrichment of cells in G2/M, followed by the appearance of multinucleated cells with some of the nuclei still being able to incorporate bromodeoxyuridine (BrdU). By fluorescent activated cell sorter (FACS) analysis, these cells appeared as polyploid cells. Prolonged activation of V12Rac or V12Cdc42 resulted in genomic instability and these cells finally detached from the culture plate. These findings indicate that induction of the constitutive active V12 forms of Rac and Cdc42 results in 'mitotic slippage', where endoreplication takes place irrespective of the exit from cytokinesis.

Animals↗

PubMed2001

Further offences by discharged psychiatric patients--can somebody be held liable?

The decision to release a state patient who is unfit to stand trial and/or not criminally responsible, who had been committed to a mental institution in terms of the Criminal Procedure Act or who was held in terms of section 28 of the Mental Health Act, may have harmful or even fatal consequences. The multi-professional team at Oranje Hospital will only institute discharge procedures regulated in terms of section 29 of the Mental Health Act when it is of the opinion that a state patient's mental illness is stable and well-controlled and his clinical picture is such that he qualifies to be discharged. In this discussion focus will be placed on: a. the two discharge procedures applied in South Africa. b. four case studies which will be presented dealing with the observation period, admission, offence, diagnosis, treatment, hospitalisation, leave periods, discharge on certain conditions, re-admission and further offences. c. the question of whether the State may be held liable for the negligent or wrongful discharge or release of a state patient who subsequently commits a serious crime.

Crime↗

PubMed1999

Cyclin D1 overexpression enhances radiation-induced apoptosis and radiosensitivity in a breast tumor cell line.

Overexpression of cyclin D1, a G1 cell cycle regulator, is often found in many different tumor types, such as breast carcinoma and squamous cell carcinoma of the head and neck. The overexpression of this protein is, in several cases, associated with a poor prognosis. In this study, the effect of cyclin D1 on radiosensitivity was investigated in a breast tumor cell line, MCF7, containing a cyclin D1 gene construct under the control of a tetracycline-sensitive regulator. MCF7 cells cultured without tetracycline resulted in a 6-fold increase in the cyclin D1 protein. Cyclin D1-overexpressing MCF7 cells were more sensitive to ionizing radiation than the nonoverexpressing counterparts. The cyclin D1-overexpressing cells also exhibited a higher induction of apoptosis. Treatment with a dose of 5 Gy resulted in a rapid increase of p53 and p21 in the cyclin D1-overexpressing cells. Nonoverexpressing cells showed a more transient expression of these proteins after ionizing radiation. A pronounced G2-M block was observed in both cell lines. The cyclin D1-overexpressing cells were, however, released earlier from the block than the control cells. These data suggest that overexpression of cyclin D1 alters sensitivity toward ionizing radiation by modulating gamma-radiation-induced G2-M transition.

Apoptosis↗

PubMed1999

CD40 engagement modulates the production of matrix metalloproteinases by gingival fibroblasts.

Chronic periodontitis is a destructive inflammatory disease linked with unbalanced production between matrix metalloproteinases (MMPs), such as interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3) and their endogenous tissue inhibitors of MMPs (TIMPs). In addition to aberrant MMP-1 and MMP-3 expression, periodontal lesions are characterized by dense infiltrations of activated T lymphocytes which may interact with CD40-expressing gingival fibroblasts in the connective tissue via the CD40L-CD40 pathway. In this study we investigated whether CD40 cross-linking influenced MMP production by gingival fibroblasts. Therefore, we analysed the CD40L-induced MMP production by these fibroblasts in the presence of cytokines that are increased in periodontal lesions, such as IL-1beta, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). We show that CD40 ligation on gingival fibroblasts resulted in a decrease of their MMP-1 and MMP-3 production, while MMP-2 and TIMP-1 production were unaffected as determined by Western blot. This down-regulatory effect of CD40 engagement on MMP-1 and MMP-3 production by gingival fibroblasts was also present when MMP production was up-regulated by IL-1beta and TNF-alpha or down-regulated by IFN-gamma. These results suggest that CD40 ligation on gingival fibroblasts leads to a restraining of MMP-1 and MMP-3 production by gingival fibroblasts and thereby may be an important mechanism in the retardation of further periodontal tissue damage.

Adult↗

PubMed1997

Epilepsy and the law.

Epilepsy, and the treatment thereof, has effects on many aspects of life, with far-reaching implications for the patient, his family and the community. Epilepsy causes a great deal of social difficulties and restrictions due to the associated stigma and prejudice. It is not a rare condition and is associated with many other conditions, such as schizophrenia, mental retardation, autism, and terminal Alzheimer's disease. Other associated disorders may include cognitive difficulties, personality disturbances or psychoses of various types and durations. Only by the 1850's was epilepsy defined as a "neurological" disease.

Automatism↗

PubMed1996

Criteria for fitness to stand criminal trial.

OBJECTIVE: To identify criteria whereby triability can be determined. DESIGN: Questionnaire survey. The final rating was decided on the basis of a structured psychiatric interview. SETTING: Oranje Hospital, Bloemfonteln. PARTICIPANTS: A total of 736 questionnaires was sent to 176 judges of the Supreme Court, 480 magistrates and 32 attorneys-general and state advocates in South Africa and Namibia, and 33 psychiatrists and 15 clinical psychologists working in forensic psychiatric units in South Africa. With the information from the completed questionnaires, rating criteria were compiled. The rating criteria were applied by means of a structured interview to 100 persons referred in terms of section 77(1) of the Criminal Procedure Act 51 of 1977. A multiprofessional psychiatric team was requested to evaluate the same 100 observandi independently. RESULTS: A total of 298 (40.5%) of the questionnaires were returned. From the data of the completed questionnaires, 19 legal items, 17 psychiatric items, 2 special laboratory tests and 2 psychosocial items were identified as the most important and clear diagnostic indications for the evaluation of triability. The similarity between the findings of the researchers and those of the multiprofessional psychiatric team was meaningful to 1% of significance. For the proper application of the criteria a cut-off point of 31 was determined. A score of 31 or higher therefore indicates that a patient is unfit to stand trial, while a score of less than 31 indicates triability. CONCLUSIONS: The application of the proposed final rating criteria as a single method of rating is at the very least just as reliable as the multiprofessional team in evaluating fitness to stand trial. The proposed criteria, used as a single rating instrument, are cost-effective in terms of time and staff, avoid unnecessary hospitalisation and ensure that mentally ill accused will have a fair trial.

Humans↗

PubMed1995

The creation and development of an instrument to determine fitness to stand trial.

A research team, consisting of a jurist and a psychologist, created and developed an instrument which could be used to effectively assess the fitness to stand trial of an accused person. A questionnaire was compiled and sent out to 736 members of both the legal and mental health professions. The information received from the response group was used to compile the fitness instrument. This instrument was applied to 100 observandi, committed to Oranje Hospital in terms of the Criminal Procedure Act, by way of a semi-structured interview. The same 100 observandi were evaluated by a multi-disciplinary team of the hospital and the results of the two groups were compared. This comparison showed a significant resemblance and it was concluded that the instrument could successfully be used as a single method of evaluating triability.

Criminal Psychology↗

PubMed1995

The protection of personal and medical data--a call for confidentiality.

Personal data and privacy are increasingly being threatened by a boom in technological development--the replacement of conventional networks of communication with the perfected combination of computer and telecommunications. The subsequent high degree of transparency has the potential to damage the individual's right to 'informational self-determination'. The most common ways of unlawfully entering a computer data system, the reasons why an individual's information is treated as confidential and the ethical issues involved, international and local statutory instruments that protect such personal information, and ways to stop the outflow of personal information are discussed.

Confidentiality↗

PubMed1995

Law and psychology: a historical perspective (1).

In this first of a series of three articles, the relationship between law and psychology is discussed from a historical perspective. The article is divided into four sections: First, the early developments are described. Secondly, the use of medical knowledge and experts in Roman law is discussed. Thirdly, attention is devoted to the legal status of the mentally ill during the Middle Ages and how the thirteenth century appears to have been a turning-point in this regard. Lastly, important medicolegal developments during the Renaissance and the replacement of the belief in witchcraft by a more scientific approach are described.

Europe↗

PubMed1995

Expert evidence: the emergence of psychiatry and psychology (2).

In this second of a series of three articles, attention is devoted to the developing role of psychiatrists and psychologists as expert witnesses. As far as psychiatry is concerned, the first recorded use of psychiatric evidence in an English court dates back to the first half of the eighteenth century, but it was not until the nineteenth century that psychiatry was recognized as a field that could contribute significantly to the law. Developments in South Africa regarding forensic psychiatry followed a similar pattern. As for psychology, immediately after its emergence as an autonomous science late in the nineteenth century, it interacted with law. Developments from the stormy early years to the present in the United Kingdom are discussed.

Expert Testimony↗

PubMed1994

Possible reasons why certain epileptics commit unlawful acts during or directly after seizures.

Courts have accepted that epileptics sometimes commit unlawful acts as a result of an epileptic seizure. Reasons for this unlawful behaviour may be found in the interictal, ictal and post-ictal phases of the seizure. Interictal aspects which are relevant to the form of epileptic automatism may be the person's natural tendencies, the same psychodynamic factors which determine the contents of dreams, the person's social background of violence and the contents of a person's thoughts immediately before a seizure. Ictal aspects include the specific part of the brain from which the seizure originates, the loss of integration of incoming sensorial stimuli with motor-emotional output, the loss of higher control associated with a reversion to primitive automatic behaviour and the emergence of repressed feelings and aggressive instincts. Post-ictal violent behaviour may stem from the epileptic's misinterpretation of well-meant attempts by bystanders to protect him or her against the consequences of his or her confused conduct--and is usually characterized by a clouded consciousness, paranoid ideas and hallucinations.

Automatism↗

PubMed1992

Cooperation between experts in fitness proceedings.

The handling of the mentally ill offender involves the law as well as psychiatry and it is, therefore, essential that a good relationship exists between the jurist and the psychiatrist. The answering of questions of law by the courts needs the assistance and cooperation of mental health experts. This cooperation between the law and mental health professions is inevitable and necessary because the court is not an expert in the field of psychiatry. The duty of the psychiatric expert is to furnish the judge with necessary scientific criteria for testing the accuracy of the conclusions, so as to enable the court to form its own independent judgment by the application of these criteria to the facts proved in evidence.

Cross-Cultural Comparison↗