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Biomedical subjects

L Howe

Publications and source records attributed to L Howe.

27 records · Page 2Linked to original sources
PubMed1998

The effect of biological substrates on the ultrafast excited-state dynamics of zinc phthalocyanine tetrasulfonate in solution.

Zinc phthalocyanine tetrasulfonate (ZnPcS4), a potential photosensitizer for photodynamic therapy (PDT), has been studied using femtosecond laser spectroscopy. The excited-state dynamics in water have been found to be fast (< 80 ps) and dominated by intermolecular aggregation. Since the proposed mechanism for PDT is energy transfer from the triplet excited state of the photosensitizer to triplet O2 creating singlet O2, the short lifetime is expected to be unfavorable for producing singlet O2. This leads to the suggestion that the presence of biological substrates may have an effect on the excited-state dynamics. To test this hypothesis, the lifetimes of the excited states of ZnPcS4 have been directly measured in the presence of a model membrane, n-hexadecyltrimethylammonium bromide (CTAB). The excited-state dynamics of ZnPcS4 in buffer solutions and with human serum albumin (HSA) have also been measured. The presence of HSA and CTAB increases the excited-state lifetime significantly relative to that observed in water. The longer lifetime of ZnPcS4 in CTAB (> 1 ns) indicates that the micellar surface favors monomer formation. By increasing the excited-state lifetime, the surface substantially increases the photosensitizing potential of ZnPcS4.

Blood Proteins↗
PubMed1997

Dental twinning.

Dental twinning anomalies influence tooth alignment and interdigitation, arch symmetry, appearance, and associated periodontal tissues. This case report presents a patient with twinning defects involving the maxillary central incisors. The aetiology of dental twinning using traditional nomenclature is also reviewed.

Adolescent↗
PubMed1996

ICG and AMPPPE.

Explore the source record for details and available documents.

Acute Disease↗
PubMed1989

The use of a caries detector dye in cavity preparation.

The aim of this study was to compare the conventional visual and tactile method of detecting carious dentine during cavity preparation using a mirror, probe and excavator with a visual method enhanced by a dye. The dye, 1% acid red in propylene glycol, was used on 100 cavities prepared by dental students and passed as clinically satisfactory by their teachers. Results showed dye stain at the enamel-dentine junction in 57 cavities (57%) which had been assessed as caries-free in this area using conventional visual and tactile means. Subsequent laboratory work on extracted carious teeth confirmed histologically that the dye stains demineralised dentine. If clinicians consider it important to render the enamel-dentine junction caries-free, it might be prudent to use the dye as an aid to diagnosis in this area.

Coloring Agents↗
PubMedDate not supplied

Personality and alcohol/substance-use disorder patient relapse and attendance at self-help group meetings.

This study evaluated the role of personality in the short-term outcome of alcohol/substance-use disorder patients. Detoxifying alcohol/substance-use disorder patients were administered the Myers-Briggs Type Indicator (MBTI), the Tridimensional Personality Questionnaire (TPQ), the Michigan Alcohol Screening Test (MAST), the CAGE Questionnaire, and the Beck Depression Inventory (BDI). These patients were subsequently evaluated over a 1-month period for relapse and attendance at self-help group meetings. High TPQ Persistence scale scores predicted abstinence. When the Thinking and Feeling groups were considered separately, and when these two groups were combined into a single group, high scores for the individual groups and the combined group (i.e. Thinking and Feeling types together) predicted abstinence. High TPQ Persistence scale scores and low Shyness with Strangers and Fear of Uncertainty subscale scores predicted attendance at self-help group meetings. High MBTI Extroversion and high MBTI Thinking scores also predicted attendance at self-help group meetings. When the Extroverted and Introverted types and the Thinking and Feeling types respectively were combined, as with abstinence, high scores predicted attendance at self-help group meetings. Age, gender, CAGE, MAST, and BDI scores did not predict outcome. The above information suggests that specific personality variables may predict abstinence and attendance at self-help group meetings in recently detoxified alcoholics, and this may have prognostic and therapeutic significance.

Adult↗
PubMedDate not supplied

Underlying personality differences between alcohol/substance-use disorder patients with and without an affective disorder.

The Myers-Briggs Type Indicator (MBTI), a popular personality test, was used to profile the personalities of in-patient alcoholics/substance-use disorder patients who had, and those who did not have, a concurrent affective disorder diagnosis. The MBTI divides individuals into eight categories: Extroverts and Introverts, Sensors and Intuitives, Thinkers and Feelers, and Judgers and Perceivers. Alcohol/substance-use disorder patients with no affective disorder differed from a normative population only in being significantly more often Sensing and significantly less often Intuitive single-factor types. The Extroverted/Sensing/ Feeling/Judging four-factor type was also significantly over-represented in this group, compared to a normative population. In contrast, mood-disordered alcohol/substance-use disorder patients were significantly more often Introverted, Sensing, Feeling, and Perceiving and significantly less often Extroverted, Intuitive, Thinking, and Judging single-factor types. They were also significantly more often Introverted/Sensing/ Feeling/Perceiving and Introverted/Intuitive/Feeling/Perceiving four-factor types. 'Pure' alcohol/ substance-use disorder patients differed from alcohol/substance-use disorder patients with a mood disorder in that they were significantly more often Extroverted and Thinking and significantly less often Introverted and Feeling single-factor types; and significantly less often were an Introverted/Sensing/ Feeling/Perceiving four-factor type. The above results may have psychogenetic, diagnostic, and psychotherapeutic implications.

Adult↗
PubMedDate not supplied

Anterior ischaemic optic neuropathy in Wegener's granulomatosis.

Is reported a case of Wegener's granulomatosis originally presenting with a clinical picture of temporal arteritis. The presentation included an arteritic anterior ischaemic optic neuropathy occurring with no demonstrable orbital inflammation. The treatment of these two systemic vasculitides is quite different, however, and this case emphasizes the importance of questioning the original diagnosis if the clinical course of the disease does not progress as anticipated.

Female↗