Biomedical subjects

A O Grobbelaar

Publications and source records attributed to A O Grobbelaar.

At least 37 records · Page 2Linked to original sources

PubMed2000

Can the carbon dioxide laser completely ablate basal cell carcinomas? A histological study.

Carbon dioxide laser ablation has been advocated as an alternative therapeutic modality for basal cell carcinoma. This study examined the limitations of carbon dioxide laser ablation for BCCs by the formal excision and histological examination of the tumour bed, following laser therapy. We evaluated the tumour type and ablation depth required to ablate the tumours completely. Fifty-one selected BCCs, ranging from 4 to 35 mm, were ablated with a carbon dioxide laser combined with a microprocessor controlled optomechanical flash scanner. Clinically there were 21 superficial, 28 nodular and 2 infiltrative types. Complete ablation at the deep margin was associated with ablation depth (P = 0.006) and with tumour type (P = 0.01). Overall, all tumours of superficial subtype (found most commonly on the trunk) could be completely ablated reliably, provided they were lasered to a depth of the middle dermis or deeper. In contrast, nodular tumours could not reliably be ablated by this method. A small subset of nodular tumours less than 10 mm diameter, however, were all completely ablated provided they were lasered to a depth of the lower dermis or deeper, however this may result in delayed healing and scarring. We conclude that this fast modality is useful for the treatment of some BCCs provided strict selection criteria are met. Laser ablation would be most beneficial for patients with multiple superficial BCCs.

Adult↗

PubMed2000

Chronic axillary hidradenitis--the efficacy of wide excision and flap coverage.

A number of different modalities of surgical treatment for axillary hidradenitis suppurativa have been suggested. This study compares three different methods of surgical excision. Fifty-nine patients (94 axillae) were treated over a 14-year period. There were 42 females and 17 males with an average age of 32 years (range 16-65 years). Twenty-six axillae had excision of only the diseased skin and recurrent disease occurred in seven. However, in 39 axillae that were treated by excision of all the hair bearing skin, only three developed recurrent disease, which is a significant reduction in the incidence of recurrent disease (P = 0.04, Fischer's exact test). Twenty-nine axillae were treated by wide local excision (2 cm beyond the hair bearing skin) and no recurrence occurred. However, there was no statistical difference (P = 0.18, Fischer's exact test) in disease recurrence between excision of all the hair bearing skin and wide local excision. This study suggests that excision of all the hair bearing skin is the preferred method of surgical treatment. Flap coverage was an effective method to achieve wound closure after adequate excision and can be achieved by random fasciocutaneous flaps for small or medium sized defects and parascapular flaps for large defects.

Adolescent↗

PubMed2000

Paralysis of the marginal mandibular branch of the facial nerve: treatment options.

Isolated paralysis of the marginal mandibular branch of the facial nerve results in an asymmetrical smile with elevation of the lower lip on the affected side. We discuss the surgical options for its correction and present a series of 26 patients who underwent either botulinum toxin injection, anterior belly of digastric transfer or free extensor digitorum brevis transfer as treatment. Botulinum toxin injection provided satisfactory results although these were temporary. Anterior belly of digastric transfer was the surgical procedure of choice. It yielded superior cosmetic results, less donor-site morbidity and required a shorter operating time. In more complex congenital facial hypoplastic syndromes, or following extensive surgery in the digastric triangle, the anterior belly of the digastric muscle may be absent or damaged. Extensor digitorum brevis transfer is the preferred option in these cases.

Adolescent↗

PubMed2000

Flexor tendon blood vessels.

The aim of this study was to assess rabbit long flexor tendon vascularity in a qualitative and quantitative manner using immunohistochemistry. The endothelial cell surface marker CD31 was targeted with a specific monoclonal mouse-anti-human antibody with good species cross-reactivity. Subsequent signal amplification and chromogen labelling allowed vessel visualization. Computer image analysis was performed. Values for vessel number and total vessel area per section, as well as the sections' cross-sectional tendon areas, were obtained. There was a consistent deep tendon avascular zone between the A2 and A4 pulley in the rabbit forepaw. This was not the case in the hindpaw, with dorsally orientated longitudinal vessels coursing the length of the intrasynovial tendon. The area of least vascularity in the hindpaw was around the metacarpophalangeal joint. We therefore recommend the use of hindpaw tendons when using the rabbit as a flexor tendon experimental model. This is because its vascular pattern is similar to that of the human flexor digitorum profundus.

Animals↗

PubMed2000

Reducing postoperative morbidity after the insertion of gold weights to treat lagophthalmos.

Paralysis of the orbicularis oculi muscle leads to an unopposed action of the levator of the upper eyelid (lagophthalmos) in facial nerve palsy. The resultant exposure of the cornea may lead to keratitis, corneal ulceration, and eventual blindness. Although many surgical options exist in the treatment of lagophthalmos, upper lid loading with a gold weight implant has become one of the preferred methods to reduce the complications that may follow. The problems encountered after gold lid loading and methods to reduce postoperative morbidity are not well documented. The objective of this study was to determine the range of morbidity seen after gold weight insertion and to evaluate the effect of supratarsal fixation on subsequent morbidity. After retrospective reviews by questionnaire and case note analysis, supratarsal fixation was found to noticeably reduce the rate of implant ulceration and extrusion. This study demonstrates upper lid loading to be an effective method for the treatment of lagophthalmos, and it supports fixation of gold weights in reducing surgical morbidity.

Adolescent↗

PubMed2000

The abnormal nucleus as a cause of congenital facial palsy.

BACKGROUND: Congenital facial palsy (CFP) is clinically defined as facial palsy present at birth. It is associated with considerable disfigurement and causes functional and emotional problems for the affected child. The aetiology of the majority of cases however, remains elusive. AIMS: To investigate the role of a neuroanatomical abnormality as a cause of unilateral CFP. METHODS: Magnetic resonance imaging (MRI) scans were performed on 21 patients with unilateral CFP. Fifteen patients had unilateral CFP only; six suffered from syndromes which can include unilateral CFP. RESULTS: Of the 15 patients with unilateral CFP only, four (27%) had an abnormal nucleus or an abnormal weighting of this area on the MRI scan, compared to one (17%) of the remaining six patients. CONCLUSION: Developmental abnormalities of the facial nucleus itself constitute an important, and previously ignored, cause of monosymptomatic unilateral CFP.

Adolescent↗

PubMed1999

Ruby laser-assisted hair removal reduces the coarseness of regrowing hairs: fallacy or fact?

There have been anecdotal reports that hairs that regrow after ruby laser-assisted hair removal are finer in appearance. If true, this phenomenon adds to the improved aesthetic effect of laser treatment of unwanted hair. It is the aim of this study to determine whether this phenomenon indeed occurs, and if so, assess its permanence and its mode of action. In this prospective clinical study, 71 patients with 94 treatment sites were treated with the Chromos 694 Depilation Ruby Laser. Hair diameter was measured pre-treatment, and at 3 and 7 months post-treatment. In addition, ex vivo scalp skin was used to assess if the ruby laser selectively damaged coarser hairs. Laser-treated and matched untreated skin samples were histologically assessed and the diameters of hair shafts (normal or obviously damaged) were measured. Results of this study were analysed using Kruskal-Wallis one-way analysis. There was no statistically significant difference between the hair diameter of non-lasered specimens and the hair diameter of the normal hair in lasered specimens. However, a statistically significant difference was seen between the hair diameter of non-lasered specimens and diameters of damaged hair in lasered specimens (P < 0.05). There was a statistically significant difference (P < 0.05) between pre-treatment and 3 month hair diameters, but no statistically significant difference was found between pre-treatment and 7 month hair diameters. In conclusion, ruby laser-assisted hair removal results in a temporary reduction in hair diameter of regrowing hair. This is not due to the selective targeting of larger hair follicles.

Adolescent↗

PubMed1999

Measurement of c-myc oncogene expression provides an accurate prognostic marker for acral lentiginous melanoma.

Acral lentiginous melanoma is a particularly aggressive tumour with a worse prognosis than other varieties of primary cutaneous melanoma. In order to study the biology of this disease, the activity of the c-myc oncogene was studied in tumours from 45 patients using flow cytometry. High levels of oncoprotein were found in all tumours and exceeded that documented in other varieties of cutaneous melanoma. Survival analysis with stratification of patients according to oncogene activity provided a useful prognostic marker with shorter disease free interval (Log-Rank test, chi 2 = 16.7, P < 0.0001) and overall survival (Log-Rank test, chi 2 = 8.9, P = 0.002) in tumours with high oncoprotein levels. Multivariate analysis revealed c-myc oncogene expression to be more accurate in predicting clinical outcome than all existing clinicopathological parameters including the Breslow depth (Cox's proportional hazards model, P = 0.0011). This study provides biological evidence to explain the aggressive behaviour of acral melanoma and supports the application of oncogene measurement as an accurate prognostic marker.

Adult↗

PubMed1999

The removal of unwanted hair using a ruby laser.

A ruby laser has been developed to remove unwanted hair. Melanin within the hair is used as a natural chromophore. It is postulated that photothermal damage destroys the hair itself and also key cells surrounding the hair follicle to prevent regrowth. A prospective study of laser depilation in 116 patients or 175 sites was performed over a period of 18 months. All the patients had tried other methods of hair removal and found them to be unsatisfactory. Hair counts (follicles/cm2) were used to judge the outcome. The mean follow-up time was 23.25 weeks (range 12-76 weeks). After a mean number of treatments of 1.92 (range 1-20) there was a 56.4% reduction in hair density. Comparing pre- and post-treatment hair density, there was a highly significant reduction (paired t-test: P < 0.00001). Laser removal of hair is now a realistic treatment option.

Adolescent↗

PubMed1999

Ruby laser-assisted hair removal: an ultrastructural evaluation of cutaneous damage.

Ruby laser-assisted hair removal is thought to act via selective photothermolysis of melanin in the hair follicles. Although initial clinical trials of permanent hair removal using ruby lasers are promising, the exact mechanisms of hair destruction and the potential damage to other structures of skin are not known. The aim of this study was to evaluate the cutaneous ultrastructural changes following ruby laser hair removal. Nineteen healthy Caucasian patients with dark (brown/black) hair were treated with the ruby laser and biopsies taken after 0, 2, 3, 5, 7, 14 and 21 days. Specimens were examined by light and electron microscopy. Laser-treated specimens showed widespread coagulation and charring of subcutaneous hair shafts. These obviously damaged follicles were randomly dispersed amongst intact follicles within the same treatment sites. Microscopic changes were also seen in the basal epidermis where melanin was concentrated, irrespective of any obvious macroscopic damage. A low level of inflammatory response seen up to 2 weeks after treatment always followed laser treatment. Suprabasal epidermal necrosis was only seen in patients with blister formation after treatment. Ruby laser irradiation results in selective damage to the hair follicles, with microscopic changes to the basal epidermis. The damage is probably compounded by the inflammatory response to the damaged hair. The normal appearance and distribution of collagen in the dermal layer supported the clinical evidence that laser-assisted hair removal, if performed correctly, does not lead to scar formation.

Biopsy↗

PubMed1999

Is Dupuytren's disease caused by an imbalance between proliferation and cell death?

Dupuytren's contracture shares certain properties with malignant tumours, characterized by proliferation and lack of apoptosis, which may be induced by the c-myc oncogene. Because of these similarities, the relationship between the c-myc oncogene expression, bcl-2 oncogene (anti-apoptotic gene) and proliferation was investigated in Dupuytren's disease. Proliferation was assessed by immunohistochemical staining of the mib-1 antibody. Results were compared with those from fibrosarcoma specimens, representing a related malignant tumour. Non-diseased fascia from Dupuytren patients and flexor retinaculum from patients undergoing carpal tunnel release without Dupuytren's disease were used as controls. Expression of c-myc was elevated in primary Dupuytren's disease and fibrosarcoma specimens, whilst recurrent Dupuytren's disease, non-diseased Dupuytren fascia and flexor retinaculum exhibited significantly lower levels. Neither bcl-2 nor mib-1 were detected in Dupuytren's disease, non-diseased fascia or flexor retinaculum, in contrast to fibrosarcoma. The imbalance between proliferation and apoptosis, producing malignant growth was thus confirmed for fibrosarcoma, but not for Dupuytren's disease.

Adult↗

PubMed1999

The effect of ruby laser light on ex vivo hair follicles: clinical implications.

Several clinical studies on the efficacy of ruby laser-assisted hair removal have reported that regrowth of hair after treatment is common. One of the reasons for the regrowth of hair is the incomplete destruction of germinative hair cells due to the insufficient penetration of the ruby laser in the skin. It was the aim of this study to estimate the extent of damage to the hair follicles after one ruby laser treatment and to determine whether the ruby laser destroyed the bulbs and the bulge regions of hair follicles. The extent of laser damage in hair shafts was determined by serial examination of six specimens of ex vivo scalp skin lasered with the Chromos 694 Depilation Ruby Laser at 14 J per square centimeter and 20 J per square centimeter. Another nine specimens of ex vivo scalp skin were similarly lasered, and monoclonal antibody LP2K was used to identify the bulge regions of the hair follicles using the immunoperoxidase technique. Damage to the bulge region was assessed from consecutive specimens, which were stained with hematoxylin-eosin stain. The mean depth of laser damage sustained by hair follicles was 1.34 mm (14 J per square centimeter) and 1.49 mm (20 J per square centimeter) underneath the skin surface. Most of the laser damage involved the bulge regions but fell short of the hair bulbs. The laser damage did not seem to extend far enough down the hair shafts to result in permanent hair destruction. The clinical implications of this finding are discussed.

Hair Follicle↗

PubMed1999

Ruby laser-assisted hair removal: a preliminary report of the correlation between efficacy of treatment and melanin content of hair and the growth phases of hair at a specific site.

An unpredictable response, even in patients with dark hair, often undermines successful ruby laser hair removal. A prospective clinical study was carried out to evaluate the roles of melanin content and growth phases of hair in treatment efficacy. Thirty-six volunteers with white skin and dark hair were recruited for the study, and were all treated using the Chromos 694 Depilation Ruby Laser. The overall efficacy of treatment was assessed at the end of 3 months. The efficacy of laser treatment is not due solely to the proportion of hair in the growing or static phase of the hair cycle. There is a lack of correlation between the melanin content and the overall efficacy of laser hair removal in those treated once, but patients with darker hair responded better after repeated treatments. The proportion of hair in the growth phase and the melanin content of hair do not contribute solely to the efficacy of ruby laser hair removal.

Hair↗

PubMed1999

The effect of ruby laser light on cellular proliferation of epidermal cells.

In ruby laser-assisted hair removal, microscopic damage is often seen in the basal epidermal cells, where melanosomes are concentrated. It is not known whether this treatment leads to cellular hyperproliferation. It was the aim of this study to investigate this. Ten white patients were treated with the Chromos 694-nm Depilation Ruby Laser, and biopsies taken before and after treatments to assess the presence of cell hyperproliferation, which normally accompanies epidermal damage, with immunohistochemical staining of keratin 16 and Ki67. No evidence of cell hyperproliferation was seen in all specimens examined after ruby laser irradiation. The authors conclude that despite the possible microscopic damages seen in the basal epidermis after laser hair removal, there is no evidence of cellular hyperproliferation. This is in contrast to ultraviolet-irradiated cell damage, in which increased basal cell turnover is seen.

Cell Division↗

PubMed1999

Ruby laser-assisted hair removal success in relation to anatomic factors and melanin content of hair follicles.

Ruby laser-assisted hair removal is thought to work via selective photothermolysis, which relies on light reaching the deeper layers of skin, and the absorption of light by the target chromophore, melanin. It is therefore possible that efficacy of treatment is affected by anatomic factors that determine the amount of light reaching the hair bulbs (i.e., skin color, depth of intracutaneous hair, epidermal thickness and dermal density) and the melanin content of hair. To examine this hypothesis, a prospective study was performed. Forty-eight volunteers were treated with the Chromos 694 Depilation Ruby Laser at a single standard fluence of 11 J/cm2. Treatment efficacy was determined by measuring hair density at 3 and 7 months after treatment. Epidermal depth and dermal density were measured from 2-mm biopsies taken before treatment, and the intracutaneous hair length was determined from plucked hair. Skin color was assessed using a spectrophotometer, and melanin content of dissolved hair was assessed using spectrophotometry. Efficacy of treatment for each patient was compared with the patient's age, intracutaneous hair length, epidermal depth, dermal density, skin color, and total melanin content and relative eumelanin content of hair. No correlation was found between the efficacy of treatment and age and the various anatomic factors. Patients with higher eumelanin content in their hair had better long-term results (Spearman rank test, p = 0.00219). The results suggested that the efficacy of treatment did not depend solely on the amount of laser light penetrating the skin but correlated well with the eumelanin content of hair. The clinical implication of this finding is discussed.

Adolescent↗

PubMed1998

Measurement of invasive potential provides an accurate prognostic marker for giant cell tumour of tendon sheath.

Giant cell tumours of tendon sheath vary from solitary nodules to a multinodular variety that exhibits local infiltration. Recent advances in molecular oncology have defined a gene, nm23, expressed in normal cells which is responsible for inhibiting infiltration. The aim of this study was to investigate the expression of nm23 in a series of 52 giant cell tumours using immunohistochemistry and to assess its prognostic potential. nm23 expression was absent in 21%, of tumours and this was associated with a highly significant risk of local recurrence (P<0.0001). Multivariate analysis of outcome showed nm23 expression to be more reliable than other clinicopathological parameters for predicting outcome. This immunohistochemical test for nm23 is easily performed on standard paraffin sections and is recommended as an accurate prognostic marker for giant cell tumours of tendon sheath.

Adolescent↗

PubMed1998

Camptodactyly: a unifying theory and approach to surgical treatment.

Camptodactyly is an isolated congenital flexion deformity of the proximal interphalangeal (PIP) joint. Surgical experience with 16 patients (18 fingers) between June 1983 and December 1994 is reported. Skin, fascia (retinaculum cutis), tendon sheaths, flexor digitorum superficialis tendon, lumbricals and interossei (particularly the lateral bands), joint surfaces, neck of the proximal phalanx, and central slip insertion were involved in all cases, although the degree of involvement can vary. Surgery must address all of these structures. Postoperative splinting is important. Fifteen patients had good or excellent results after surgery, with a mean gain in motion of 57 degrees (range, 0 degrees-90 degrees). Surgery should be aimed at prevention of progressive deterioration and is probably not indicated in minor degrees of the deformity. Surgery should be reserved for patients with a preoperative PIP joint contracture of more than 60 degrees.

Child↗

PubMed1998

Cellular proliferation characteristics do not account for the behaviour of horrifying basal cell carcinoma. A comparison of the growth fraction of horrifying and non horrifying tumours.

This study compared the clinical features, histological subtype, growth fraction (by Ki67 immunohistochemistry) and proliferation pattern of 22 clinically defined horrifying basal cell carcinoma compared to 81 non horrifying lesions. Late presentation was associated with half of the horrifying tumours. The other half developed horrifying tumours despite early intervention. The horrifying tumours exhibited a variety of histological growth patterns. A total of 50% were infiltrative, 23% nodular and 18% micronodular. There was no difference in the growth fraction or proliferation pattern between horrifying and non horrifying tumours of similar growth pattern (P = ns), although infiltrative tumours in either group exhibited a significantly higher growth fraction than nodular tumours (P < 0.01). This suggests that there is no intrinsic biological difference between horrifying and non horrifying tumours to account for their behaviour. We conclude that late presentation, failed or inadequate early management especially of infiltrative tumours (and other subtypes) determines the development of horrifying tumours.

Adult↗