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Biomedical subjects

J L Hawk

Publications and source records attributed to J L Hawk.

At least 37 records · Page 2Linked to original sources
PubMed1999

F-chronodispersion in patients on thalidomide.

OBJECTIVES: To describe abnormalities of F-chronodispersion in patients treated with thalidomide. METHODS: We retrospectively studies F-wave latency, persistence and F-chronodispersion in 12 patients on thalidomide treatment and compared them with a control group of another 12 patients with similar dermatological conditions who did not receive thalidomide. Furthermore, we prospectively performed longitudinal neurophysiological studies in 4 patients before and during thalidomide treatment. RESULTS: Seven of 12 patients in the retrospective study had abnormal F-chronodispersion while this was normal in all patients of the control group (P = 0.014). All other neurophysiological parameters were similar in the two groups. Two of the thalidomide patients with abnormal F-chronodispersion later developed sensory neuropathy. In all 4 patients in the prospective study though F-chronodispersion was normal before thalidomide it became markedly abnormal after exposure to this drug. CONCLUSIONS: Thalidomide may affect smaller diameter motor nerve fibres even before changes in sural sensory nerve action potentials. F-waves and F-chronodispersion should be routinely monitored in patients on thalidomide treatment.

Adolescent↗
PubMed1999

Actinic prurigo and polymorphic light eruption: common pathogenesis and the importance of HLA-DR4/DRB1*0407.

Actinic prurigo (AP) and polymorphic light eruption (PLE) both belong to the group of idiopathic photodermatoses, but it remains controversial whether AP is a distinct photodermatosis or a variant of PLE. The aim of this study, by collecting data from 119 patients with features of these disorders, was to establish whether specific criteria could be used to distinguish AP from PLE prospectively. We found that presence of the eruption on both exposed and covered sites, its occurrence in winter, persistence of lesions beyond 4 weeks, mucosal and conjunctival involvement, excoriation and scarring of the skin were important features of AP which were not typical of PLE. On this basis, confident clinical diagnoses could be reached in 103 of 119 patients (87%), 57 with AP and 46 with PLE, supported by phototesting and negative lupus serology. HLA typing subsequently confirmed the strong association (90%) between AP and the DR4 allele, in particular with the rare subtype DRB1*0407 which was present in 60% of these patients. No HLA association was found in PLE. In the 16 remaining cases, however, clinical overlap meant that no definite diagnosis could be made; these patients were notionally described as having persistent PLE (PPLE). Demographic and HLA data in this group suggested that PPLE was perhaps most appropriately grouped with PLE. In addition to those patients who were difficult to classify, 35% of our typical AP patients also described clinical progression from PLE to AP, AP to PLE or coexistence of both AP and PLE. In conclusion, our study suggests that while AP and PLE are clinically distinct conditions in most cases, they may perhaps share a common pathophysiological basis. The AP phenotype may be determined by HLA and perhaps other factors in patients otherwise predisposed to PLE.

Adolescent↗
PubMed1999

Lichenoid tissue reaction in porphyria cutanea tarda.

We report a patient presenting with lichenoid plaques on exposed skin who had the metabolic features of porphyria cutanea tarda (PCT). Histology of lesional skin demonstrated a lichenoid inflammatory cell infiltrate in the upper dermis, while direct immunofluorescence revealed immunoreactive colloid bodies. Monochromator irradiation testing demonstrated photosensitivity in the visible spectrum consistent with porphyria. Solar-simulated irradiation induced a papular reaction with lichenoid histological changes. We propose that this atypical presentation of PCT may reflect a lichenoid tissue response to a porphyrin-mediated photochemical reaction.

Facial Dermatoses↗
PubMed1999

Polymorphic light eruption occurring solely on an area of naevoid telangiectasia.

We report the case of a 60-year-old woman presenting with polymorphic light eruption occurring solely on an area of acquired naevoid telangiectasia. We have hypothesized that increased blood flow in the telangiectatic skin may reduce the threshold for expression of photosensitivity by permitting enhanced inflammatory cell trafficking to the overlying tissue.

Estrogen Replacement Therapy↗
PubMed1999

Polymorphic light eruption occurring in common variable hypogammaglobulinaemia, and resolving with intravenous immunoglobulin therapy.

A 55-year-old woman with a past history of lower respiratory tract infections presented with a photosensitive eruption. Polymorphic light eruption (PLE) was diagnosed on the basis of the temporal relationship to sun exposure and the diagnosis was supported by positive monochromator irradiation tests in the ultraviolet A wavelength spectrum. Investigation of the patient's immune status identified low levels of all immunoglobulin (Ig) subtypes consistent with common variable hypogammaglobulinaemia. Intravenous Ig replacement therapy, instituted to minimize risks from bacterial infections, was commenced and over the ensuing months resulted in a complete resolution of the PLE. PLE is considered to represent a type IV hypersensitivity reaction directed against a cutaneous autoantigen induced by exposure to ultraviolet light. In PLE, nonspecific immunomodulatory mechanisms of intravenous Ig may be active, such as a reduction in the synthesis of cytokines and a blockage of the IgG Fc receptors on macrophages.

Adjuvants, Immunologic↗
PubMed1999

Mutations in the translation initiation codon of the protoporphyrinogen oxidase gene underlie variegate porphyria.

Variegate porphyria (VP), one of the acute hepatic porphyrias, is characterized by a reduced catalytic activity of protoporphyrinogen oxidase (PPO), the penultimate enzyme in the porphyrin-haem biosynthetic pathway. VP has been linked to the PPO gene on chromosome 1q22-23, and several mutations underlying this disorder have been described recently. In this study, we identified two different missense mutations in the translation initiation codon of the PPO gene in two unrelated patients with VP. Mutation analysis was carried out using PCR, heteroduplex analysis, automated sequencing, and restriction enzyme digestion. In the first patient, the results revealed an A-to-T transversion (ATG --> TTG), resulting in the substitution of methionine by leucine (M1L). The mutation detected in the second patient was a T-to-C transition (ATG --> ACG), leading to the conversion of methionine to threonine (M1T). These mutations abolish the initiation of translation at the normal site, and consequently, translation of an abnormal messenger RNA (mRNA) would result in the synthesis of a truncated PPO protein lacking the amino terminus.

Adenosine↗
PubMed1998

Hydroa vacciniforme presenting in an adult successfully treated with cyclosporin A.

Hydroa vacciniforme (HV) is a rare photodermatosis first described by Bazin in the mid-nineteenth century. It typically presents in childhood and resolves during adolescence. Rarely, however, symptoms may persist into adult life.2,3 We now describe a patient with this condition presenting unusually for the first time at the age of 58 years and responding to treatment with cyclosporin A.

Cyclosporine↗
PubMed1998

A clinicopathological study of the effects of topical retinyl propionate cream in skin photoageing.

The clinical and histological effects of retinyl propionate cream (a retinyl ester) on extrinsic skin ageing (photo-ageing) in man were assessed in a double-blind randomized placebo-controlled study of 80 subjects, individual parameters of this being assessed for each treatment site (face, dorsal right forearm and hand, dorsal left forearm and hand) at intervals throughout the study, while skin surface replicas from sites of fine wrinkling around the eye and skin biopsies from the dorsal right forearm were also regularly reviewed throughout. Seventy-five subjects completed an initial 24-week study period, following which 60 elected to continue for a further 24 weeks. Although minimal trends towards improvement occurred, no statistically significant differences between the effects of the retinyl propionate cream and the placebo preparation were apparent for any of the clinical, histological or profilometric parameters of skin photoageing; however, in the very few subjects affected, actinic keratoses in the active group were reduced virtually to zero by week 48.

Administration, Cutaneous↗
PubMed1998

Impact of life events on the onset of vitiligo in adults: preliminary evidence for a psychological dimension in aetiology.

The present study retrospectively examines the role of stressful life events in the onset of vitiligo in adults. A matched clinical sample of patients with other forms of disfigurement or skin disease (dystrophic epidermolysis bullosa and naevi, not thought to be associated with stress) served as a control group. Newly diagnosed patients and matched controls were thus asked to complete the 12-month version of the Schedule of Recent Experience, a questionnaire which measures the frequency and number of stressful life events occurring over a specified period. The results suggest that such patients endure a significantly higher number of stressful life events than do controls, suggesting that psychological distress may have contributed to the onset of their condition. The implications of the results are discussed and suggestions made for future research.

Adult↗
PubMed1998

Homozygous variegate porphyria: identification of mutations on both alleles of the protoporphyrinogen oxidase gene in a severely affected proband.

Homozygous variegate porphyria is a severe skin and neurologic disease manifesting in early infancy, and characterized by markedly reduced levels of the penultimate enzyme in the heme biosynthetic pathway, protoporphyrinogen oxidase. We investigated the molecular basis of variegate porphyria, usually an autosomal dominantly inherited trait, in a severely affected female proband and her parents. The mutation detection strategy included heteroduplex analysis, automated sequencing, and allele specific oligonucleotide hybridization. We identified two underlying missense mutations in the protoporphyrinogen oxidase gene, consisting of a G-to-A transition in exon 6 (G169E), and a G-to-A transition in exon 10 (G358R). Our study establishes the molecular basis of "homozygous" variegate porphyria for the first time, in demonstrating that this patient is a compound heterozygote for two different missense mutations in the protoporphyrinogen oxidase gene.

Adult↗
PubMed1998

Sesquiterpene lactone mix contact sensitivity and its relationship to chronic actinic dermatitis: a follow-up study.

In a retrospective case note analysis over a 4-year period, 0.9% of all patients tested with a standard patch test series (65 of 7600) were demonstrated to have clinically relevant responses to a sesquiterpene lactone (SQL) mix. Of these patients, 11 (17%) also had a diagnosis of chronic actinic dermatitis. This group made up 25% of all patients diagnosed as suffering from CAD in this 4-year period. These figures differ somewhat from those reported by our group in an initial 4-year period immediately following the introduction of the mix into our standard patch test series, when 1.5% of all patients tested had a clinically relevant response to the SQL mix, including 36% of all patients with a diagnosis of CAD. It is not uncommon for the prevalence of sensitivity to an allergen to be overestimated immediately following its introduction into routine testing. Possible reasons for our findings are discussed.

Asteraceae↗