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Biomedical subjects

P Laidler

Publications and source records attributed to P Laidler.

At least 55 records · Page 3Linked to original sources
PubMed1988

Acquired Brown's syndrome in a patient with combined lichen sclerosus et atrophicus and morphoea.

A 49-year-old woman with generalised lichen sclerosus et atrophicus and morphoea developed bilateral Brown's syndrome. Some of the skin lesions were in the vicinity of the trochlea. A characteristic feature of morphoea is subcutaneous fibrosis, so we postulate that the cause of the Brown's syndrome was mechanical tethering of the superior oblique tendon by deep subdermal fibrosis. Histopathological diagnosis was made from biopsies of similar lesions on the patient's face.

Female↗
PubMed1988

The prognostic significance of tumor vascularity in intermediate-thickness (0.76-4.0 mm thick) skin melanoma. A quantitative histologic study.

The vascularity of 20 primary skin melanomas was assessed histologically. These cases were selected from patients with intermediate thickness melanomas (0.76-4.0 mm thick) treated surgically to provide two groups of ten patients. One group had no evidence of recurrence with a minimum follow-up of 9 years. The second group of ten patients developed locoregional or systemic metastasis under follow-up, and seven of these patients died of disseminated melanoma. Age, sex, Breslow's tumor thickness, and Clark's level of invasion were similar in the two groups. Vascular quantitation was carried out by image analysis after vascular definition by Ulex europaeus-I agglutinin staining. The percentage vascular area at the tumor base in the recurrence group was more than twice that in the recurrence-free group. This study suggests that increased vascularity at the tumor base may have prognostic significance in intermediate thickness melanomas.

Blood Vessels↗
PubMed1986

Neovascularization in human cutaneous melanoma: a quantitative morphological and Doppler ultrasound study.

A study of tumour blood flow in 36 patients with 38 malignant melanomas using Doppler Ultrasound flowmetry has shown that tumour blood flow can be detected in most melanomas more than 0.9 mm thick, and is absent in most melanomas less than this thickness. Histological quantitation of blood vessels using lectin staining to delineate vascular endothelium and automated image analysis has shown a high degree of correlation between vascularity at the tumour base and tumour thickness. Since it is likely that the development of a vascular plexus at the tumour base is a prerequisite for dissemination, the development of these blood vessels may prove to be an independent prognostic factor for thin melanomas. This work also provides a new model for dynamic, in vivo investigation of the vascularity of human tumours.

Adult↗
PubMed1986

Can late recurrence of melanoma be predicted at the time of primary treatment.

A cohort of patients followed post-operatively in the Department of Surgery at the University of Wales College of Medicine has been studied to determine whether there were specific factors associated with late recurrence of malignant melanoma. The incidence of late recurrence (beyond 5 years after primary treatment) was 6.1%, seen predominantly in females with lesions of intermediate thickness. No more specific criteria could be defined to identify this small group of melanoma patients, and which might be useful in selecting patients requiring longer term careful follow-up. Since most late recurrence is loco-regional, self-examination by the patient may be the best pragmatic approach to facilitate early diagnosis of recurrent disease without imposing a heavy burden on the follow-up services of the health system.

Adult↗
PubMed1985

Malignant melanoma of the hand and foot: diagnosis and management.

Forty-six patients with melanoma of the hand (5) and foot (41) studied prospectively between 1972-84 have been reviewed to determine guidelines for diagnosis and management. The clinical appearance is varied and the lesions are often misdiagnosed as warts or fungal infections. Clinical assessment of tumour thickness on the sole is difficult because of the nature of the plantar skin. Incision rather than excision biopsy is indicated because of the functional consequences of large excisions on the hand and foot. Melanoma of the toe was treated by local metatarsophalangeal amputation. Plantar melanomas were excised with a 3 cm margin. Dorsum melanomas were treated by a selective policy of 1, 2 or 3 cm margins according to clinical assessment of tumour thickness. These policies have resulted in only one case of local recurrence. An in situ Silastic foam mould facilitates immediate application of split skin grafts to irregular areas. The functional results of split skin grafts on sole and heel have been satisfactory. Toe lesions were thickest, dorsum thinnest, sole and heel intermediate. The prognosis related to these groupings of tumour thickness. Simultaneous clinical nodal involvement carried a hopeless prognosis, and most patients developing nodes within 2 years die--unless treated by prophylactic dissection. The role of prophylactic dissection is still not defined, but it is likely that it will be used more frequently in the future. Early diagnosis offers most hope of improving the outlook. Many elderly patients with nodular lesions have had moles for many years. Younger patients are now being seen with thin lesions, even on the toe.

Adult↗
PubMed1985

What's new in Osmosin and intestinal perforation?

New formulations of drugs may have unexpected side effects. Osmosin is a new osmotic-pump controlled-release formulation of Indomethacin, designed to prevent gastrointestinal irritation. However, in a small number of cases the use of Osmosin has coincided with perforation of the small and large intestine, probably because passage of the tablet through the gastrointestinal tract was impeded.

Aged↗
PubMed1984

Pineal germinoma with syncytiotrophoblastic giant cells: a case with panhypopituitarism and isosexual pseudopuberty.

A previously healthy boy, aged 12 years, developed hypopituitarism due to suprasellar metastases from a pineal germinoma with syncytiotrophoblastic giant cells (SGC). Despite the hypopituitarism, the patient showed pubertal development, which was associated with abnormal levels of human chorionic gonadotropin (hCG) in the cerebrospinal fluid. This case adds support to the theory that precocious puberty in children with pineal germinomas may be due to the secretion of hCG by SGC, a minor component of the germinoma. It also illustrates the point that, although abnormal levels of circulating hCG in children with pineal tumors may indicate a diagnosis of choriocarcinoma with its encumbent poor prognosis, other pineal germ cell tumors may also secrete hCG. Although this patient had abnormal levels of hCG, his cerebral tumor exhibited behavior more commonly associated with pineal germinoma than with choriocarcinoma.

Adolescent↗
PubMed1982

The hemolytic activity of (Fab-Fc) recombinant immunoglobulins with specificity for the sheep red blood cells.

Antibody-like molecules were formed by artificial recombination of proteolytic IgG fragments (Fab' with anti-SRBC activity, and Fc) and used for studies concerning the complement fixation. Such molecules, when composed of single Fab' bound to Fc fragment appeared inactive, while species containing two Fab' fragments revealed the hemolytic activity. The results were discussed and interpreted, assuming that the interaction of Fab domains with CH2 domains in the Fc fragment is a main structural effect influencing the binding of the complement.

Animals↗
PubMed1978

Ultrastructure of carotid body in rats living at a simulated altitude of 4300 metres.

We studied the ultrastructure of the carotid body of three normal rats and three rats living in a hypobaric chamber at a pressure of 460 mm Hg for 27, 28 and 35 days respectively. The type I cells of the carotid bodies of our hypoxic rats were enlarged due to an increase in the volume of their cytoplasm. Many of their dense core vesicles were vacuolated and the core was displaced eccentrically to become adherent to the limiting membrane of the vesicle. The concentration and distribution of dense core vesicles remained unaltered and there were no obvious changes in the mitochondria, ribosomes or Golgi apparatus. There was pronounced capillary dilatation in the carotid bodies of all three rats exposed to chronic hypoxia. This change was accompanied by attenuation of capillary endothelial cells and increased frequency of endothelial fenestrations. There were no structural changes in the type II cells.

Altitude↗
PubMed1978

Synthesis of combined protein antigens. Cross-linking of Hg-(p-chloromercuribenzoate) and--SH(thiolactone) substituted proteins.

The method of coupling of -Hg (p-chloromercuribenzoate) substituted proteins with protein substituted by -SH (thiolactone) groups was designed to obtain AnBm type copolymers not associated with An or Bm homopolymers. Reaction of p-chloromercuribenzoate with human serum albumin (HSA) was performed in 1.47 M imidazole. The conjugate was treated with thiolated proteins (human immunoglobulin G or human serum albumin). Disulfide linking of thiolated proteins was negligible under the conditions used. The total yield of polymerization reached the value 35%-75% of proteins taken for the reaction. It depended on the amount of reactive groups substituted and ratio of proteins A/B, used for cross-linking. The results were confirmed by theoretical calculations based on Bernoulli distribution.

Antigens↗
PubMed1975

A quantitative morphological study of the carotid bodies of rats living at a simulated altitude of 4300 metres.

A quantitative histological study was carried out on the carotid bodies of 10 normal rats and 10 rats living in a hypobaric chamber at a pressure of 460 mm Hg from 25 to 96 days. In the chronically hypoxic rats there was a four-fold increase in the mean combined volume of the carotid bodies. Morphometric analysis disclosed a three-fold increase in the mean volume of specialised glomic cells and a ten-fold increase in the mean volume of capillaries, although the proportion of glomic cells was actually significantly decreased. In all our hypoxic rats there was evidence of both right and left ventricular hypertrophy. However, there was no linear relation between total carotid body volume or volume of glomic cells on one hand and the right and left ventricular weight, on the other hand. Although there was no linear relation between combined total carotid body volume and duration of hypoxia, the linear relation between glomic cell volume and duration of hypoxia was significant at the 5 per cent. level. The increase in vascularity of the hypoxic carotid body may be a mechanism to increase blood flow and thus oxygen transport to a hypoxic organ with increased metabolic activity. Small quantities of an amorphous hyaline material of unknown nature were found in relation to capillaries and type I cells in all the hypoxic rats.

Adaptation, Physiological↗
PubMed1975

The effect of chronic hypoxia on the number and nuclear diameter of type I cells in the carotid bodies of rats.

We measured the number and nuclear diameter of type I cells in the carotid bodies of 10 normal rats and in 10 rats living in a hypobaric chamber at a pressure of 460 mm Hg for 25 to 96 days. In normal rats, the number of type I rats, the number ranged from 15.92 to 30.77 times 10-3 with a mean of 40.79 times 10-3 which differed significantly from that in the control group. In 5 hypoxic rats the number of type I cells was less than the highest figure in the control group. The mean diameter of the nuclei of type I cells of hypoxic rats (5.5 mu) was greater than that of the controls (5.0 mu). The largest type I nuclei were seen in those rats which had been subjected to hypoxia for the shortest time.

Animals↗