Characteristics of the inhibition of human promyelocytic leukaemia HL60 cell growth by S-D-lactoylglutathione in vitro

The mechanism of the inhibition of proliferation of human leukaemia 60 (HL60) cells by S-D-lactoylglutathione in vitro was investigated. The median inhibitory concentration IC50 value was 66 microM (95% C.I. 50-87 microM; n = 18). The inhibition of leukaemia cell growth required exposure of HL60 cells to S-D-lactoylglutathione (and metabolites) for 12 h, with maximum growth inhibition achieved after 24 h. Removal and replacement of culture medium within the initial 12 h of culture prevented inhibition of growth and toxicity. S-D-lactoylglutathione was consumed within the initial 3 h of culture. Pretreatment of culture medium containing 10% foetal calf serum for 3 h produced no subsequent inhibition of HL60 cell growth. Incubation of HL60 cells in culture medium with low serum content (5% v/v) produced a decreased rate of cell proliferation and a decreased response to S-D-lactoylglutathione. S-D-lactoylglutathione inhibited uptake of 3H-thymidine into DNA in the third hour of culture where the median inhibitory concentration IC50 value was 74 microM (95% C.I. 51-102; n = 10). The mechanism of inhibition of HL60 cell growth by S-D-lactoylglutathione is unknown but may be cell cycle related, mediated by inhibition of DNA synthesis and involve an active metabolite which may be removed and/or inactivated by a change in culture medium.

Gastrointestinal symptoms in Parkinson disease: 18-month follow-up study

In a recent study we identified abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction as those gastrointestinal (GI) symptoms associated with Parkinson disease (PD) and characterized their relationship to PD severity and therapy. In this study, we re-evaluated these symptoms and their relationship to parameters of PD 18 months later. Sixty-six percent of the original participants responded. Over the 18 months, 68% of originally untreated PD subjects commenced anti-PD therapy. Abnormal salivation, dysphagia, nausea, constipation, and defecatory dysfunction were again identified as those GI symptoms more common in PD. Constipation increased both in severity and frequency. Comparison of GI symptom scores and parameters of PD dysfunction failed to reveal significant progression of either GI symptomatology or PD dysfunction, or the development of new GI symptoms over the 18-month period. This study validates our GI dysfunction assessment system and confirms abnormal salivation, dysphagia, nausea, constipation, and defecatory function as those GI symptoms truly associated with PD. A direct relationship between PD and its related GI symptoms is again supported.

Treatment of cutaneous squamous cell carcinomas by intralesional interferon alfa-2b therapy

BACKGROUND AND DESIGN

Intralesional recombinant interferon alfa-2b has been shown to be effective in the treatment of actinic keratoses and basal cell carcinomas. This open-label study was designed to evaluate the effectiveness and cosmetic result of this therapy on actinically induced, primary cutaneous squamous cell carcinomas. Thirty-six squamous cell carcinomas (28 invasive lesions and 8 in situ lesions) ranging in size from 0.5 to 2.0 cm in the longest dimension were treated with interferon alfa-2b 1.5 million units injected intralesionally three times per week for 3 weeks. Eighteen weeks following therapy, the treatment sites were excised and examined for histologic evidence of remaining tumor.

RESULTS

Thirty-three (97.1%) of 34 evaluable lesions revealed an absence of squamous cell carcinoma histologically after therapy, although three biopsy specimens (8.8%) obtained after treatment showed actinic keratoses, for an overall complete response rate of 88.2%. The lesion not eliminated after treatment was an invasive squamous cell carcinoma. The investigators and patients independently judged 93.9% of cases to have a very good or excellent cosmetic result. Adverse reactions were limited to those influenzalike symptoms well recognized to occur with interferon therapy and these were well tolerated. Only one patient discontinued therapy due to side effects.

CONCLUSIONS

This trial demonstrates that intralesional interferon is effective in the treatment of small sun-induced squamous cell carcinomas with well-tolerated side effects and a highly acceptable cosmetic result.

Patient discharge planning documentation in an Australian multidisciplinary rehabilitation setting

This article, drawing on data from 17 case studies, addresses problems in documentation of discharge planning in an Australian multidisciplinary rehabilitation center and the ways these were, or could be, overcome. The problems identified in the case studies were not specific to one discipline; they were due to inadequately defined guidelines and responsibility and poorly designed forms, and they possibly reflected the tendency for members of practice-oriented disciplines to see documentation as low on their list of priorities.

Vulvar cicatricial pemphigoid as a lichen sclerosus imitator. A case report

Because vulvar lichen sclerosus is very common, a clinician confronted with hypopigmentation and agglutination of the labia minora is tempted to make a diagnosis of the disease without the benefit of a skin biopsy or a careful examination of other epithelial surfaces. Unfortunately, that clinical picture is also consistent with the end stage of several other diseases, including cicatricial pemphigoid (benign mucous membrane pemphigoid), as demonstrated by a case of cicatricial pemphigoid affecting the vulva.

Reiter's syndrome of the vulva. The psoriasis spectrum

BACKGROUND

Reiter's syndrome is a disease characterized by crusted, scaling, acral and genital plaques; urethritis or cervicitis; and arthritis, which occur in genetically susceptible patients in response to any of many infections. This disease rarely occurs in women, and specific characterizations of vulvar and cervical lesions are rare.

OBSERVATIONS

We describe a 39-year-old woman with a history of mucocutaneous candidiasis that was refractory to oral ketoconazole therapy. She presented with well-demarcated, erythematous, crusted plaques over the vulva, hands, and feet, as well as with cervical lesions and a history of conjunctivitis and iritis. Following the biopsy of characteristic skin lesions, recognition of systemic signs, and cultures that were negative for yeast, her condition was diagnosed as Reiter's syndrome.

CONCLUSIONS

Reiter's syndrome of the vulva, vagina, and cervix may not be recognized because of its uncommon occurrence in women and the physician's consequent unfamiliarity with its clinical appearance in the genital area. This disease and pustular psoriasis share many common features and exist on a spectrum. A high index of suspicion and correlation of the many facets of the disease will better enable the clinician to make this diagnosis.

Selective memory for sensory and affective information in chronic pain and depression

Mood congruity effects in induced mood states and affective disorders are well established. Recent evidence suggests that a similar process occurs in chronic pain patients, although the extent to which the memory bias is a consequence of the affective or sensory state of the subject in this group is unknown. In this study selective memory for sensory and affective pain-related information was investigated in depressed and non-depressed chronic pain patients and depressed psychiatric patients. A recall test comprising sensory, affective and neutral adjectives matched for frequency was followed by a recognition task, where the words of the recall test were randomized with an equal number of new adjectives matched for word type and frequency. Comparison of the three patient groups with normal controls revealed specific recall biases directly related to pain and depression in both chronic pain groups and the controls. Contrary to expectations, the depressed psychiatric patients failed to show a recall bias for affective adjectives: the possibility of cognitive avoidance as an explanation for this is discussed. Signal detection analysis of the recognition results suggested that selective memory in chronic pain and depression may to some extent be accounted for by differences in 'true memory', the contribution of response bias remaining less clear.

Desquamative vulvitis

The typical appearance of inflammatory and bullous diseases may be changed when they occur on the vulva. The moist, warm, occluded environment produces a tendency for the thin skin of the vulva to erode and scar, resulting in a common final appearance often characterized by loss of the labia minora and agglutination of the clitoral hood. The most common diseases that may produce desquamative vulvitis include lichen sclerosus, lichen planus, immunobullous diseases, contact dermatitis, erythema multiforme, lupus erythematosus, and squamous cell carcinoma in situ. The differentiating characteristics and treatment of these diseases are discussed in this article.

Therapeutic response to somatostatin analogue, BIM 23014, in metastatic prostatic cancer

Metastatic prostate cancer is well known to respond to hormonal manipulations, but once progression occurs new treatment modalities are required. Specific and systemic antitumour therapy is preferable to local treatments such as radiotherapy in such patients. The finding that somatostatin analogue, BIM 23014, inhibits prostatic tumour growth in animal models is of great interest. We treated 25 poor risk patients with progressive metastatic prostate cancer. Sixteen had also failed to respond to 'total androgen blockade'. Two patients have achieved a partial remission, one of which is maintained at over 30 months, and three had stable disease for over 6 months. Side effects have consisted of mild diarrhoea and abdominal cramp in the first few days of treatment in a minority of the patients. These results are encouraging and further randomized studies are in progress.

Acceleration of alveolar type II cell differentiation in fetal rhesus monkey lung by administration of EGF

To examine the effect of epidermal growth factor (EGF) on lung parenchymal maturation in fetal rhesus monkey, recombinant human EGF was administered intraperitoneally (IP) at 66 mg/kg body wt over a 7-day period into the fetal peritoneal cavity alone or IP and into the amniotic fluid (AF) simultaneously. The saline carrier was injected IP and AF into control (CO) fetuses. The body weights of the IP + AF group were significantly larger than CO. Overall lung growth, measured as wet lung weight or fixed volume of the right cranial lobe, was unchanged. Fixed lung volume per gram body weight was significantly lower for both IP + AF and IP compared with CO. Morphogenesis of lung parenchyma, measured as percent parenchymal airspace or airspace size, was unchanged. Alveolar type II cell ultrastructure was significantly altered by EGF treatment; volume fraction of cytoplasmic glycogen was 50% less and lamellar bodies threefold greater for IP + AF and IP groups compared with CO. Total phospholipid content of AF was not altered, but relative percentages of different phospholipids were changed by EGF treatments; phosphatidylinositol was significantly reduced, and phosphatidylglycerol was significantly elevated. The lecithin-to-sphingomyelin ratio was unchanged. Surfactant apoprotein A concentration in AF was significantly elevated and was detected by immunoperoxidase in more cuboidal alveolar cells in EGF-treated animals when compared with CO. We conclude that exogenous EGF administered in the last trimester of pregnancy accelerates structural and functional cytodifferentiation of the alveolar type II cell in fetal primates. These maturational changes occur in the absence of significant alterations in overall lung growth or morphogenesis of the gas exchange area.

Intralesional interferon therapy for basal cell carcinoma

In a clinical trial of 172 patients at four medical centers, interferon alfa-2b (1.5 x 10(6) IU) or a placebo was injected directly into biopsy-proved noduloulcerative or superficial basal cell carcinomas three times weekly for 3 weeks, for a cumulative dose of 13.5 million IU. Efficacy of treatment was determined at 16 to 20 weeks by examination of biopsy specimens that demonstrated cure of lesions in 86% of interferon-treated patients and in only 29% of placebo-treated patients. During the treatment course and follow-up, an initial inflammatory response was observed at the treatment sites, followed by diminished erythema, improvement in overall appearance, and a decrease in size of lesions. Side effects of treatment, mainly flu-like symptoms, were usually mild and transient and occurred more commonly in the interferon-treated group. Only three patients, all in the interferon-treated group, discontinued therapy because of side effects. One year after initiation of therapy, 81% of interferon recipients and 20% of those given the placebo remained tumor free. Noduloulcerative and superficial lesions were equally responsive to treatment with interferon. For some patients with noduloulcerative or superficial basal cell carcinomas, intralesional interferon alfa-2b may be an alternative, effective treatment.

The effect of an intralesional sustained-release formulation of interferon alfa-2b on basal cell carcinomas

Intralesional interferon alfa-2b has been proven effective in the treatment of basal cell carcinomas. Because nine injections over a 3-week period have been necessary to produce clinically significant cure rates, a sustained-release protamine zinc chelate interferon formulation has been developed. In this study, 65 basal cell carcinomas were treated in one of two dosing schedules with intralesional sustained release interferon alfa-2b (10 million IU per injection). Thirty-three patients received a single injection and 32 patients received one injection per week for 3 weeks. At study week 16, 80% of evaluable tumors treated with three injections and 52% treated with one injection were cured histologically. Two patients discontinued injections because of side effects. A sustained-release protamine zinc preparation of interferon alfa-2b shows promise as a practical, effective, and cosmetically elegant treatment for basal cell carcinoma.

What on earth are we drinking?

During the past few years there has been a considerable increase in the number and variety of still and carbonated bottled drinking waters, which have an enormous variation in calcium content ranging from 0 to over 500 mg/l. Patients with upper urinary tract stones are often advised to maintain a high fluid intake in order to achieve an increased urinary output. If they find tap water unpalatable and drink bottled water instead, they could significantly increase their daily calcium intake by as much as 1.5 g. The majority of bottled waters presently available in this country, together with tap water samples from throughout the British Isles, have been analysed and the results suggest that there are some waters which stone formers should avoid.

Midnight removal: an improved approach to removal of catheters

There is no recognised policy regarding the timing of urethral catheter removal, although early morning removal is commonly practised. Removing the catheter at midnight allows patients to return to a normal voiding pattern more rapidly and to leave hospital earlier.

The effect of topical interferon alpha 2b on actinic keratoses

As a result of the known effects of intralesional interferon alfa 2b (Intron A) on actinic keratoses, we have now examined the effects of topical interferon alfa 2b gel on actinic keratoses. Twenty-four subjects each treated three actinic keratoses with either interferon gel 30 million IU/gm or a placebo preparation applied topically 4 times a day for 4 weeks. Although more lesions treated with the active interferon showed clinical improvement, this difference was not statistically significant.

The effect of intralesional interferon gamma on basal cell carcinomas

This open label study evaluated the effect of nine intralesional injections of two different doses of interferon gamma on basal cell carcinomas in 29 patients. One group of 15 patients received interferon gamma, 0.01 mg (20,000 IU), intralesionally three times a week for 3 weeks. Fourteen patients received interferon gamma, 0.05 mg (100,000 IU), intralesionally in the same dosage schedule. Excisional biopsy specimens 12 weeks after therapy showed no evidence of tumor remaining in 7 of 14 patients (50%) treated with the higher dose of interferon gamma, whereas only 1 of 15 patients (7%) treated with low-dose interferon gamma was cured according to histologic criteria (p = 0.025). Seventy-six percent of patients reported at least one adverse reaction, but most were considered mild by the patient and the investigator.

Vulvar lichen planus

The clinical presentation of lichen planus of the vulva spans a spectrum from subtle, fine, reticulate papules to severe erosive disease accompanied by scarring and loss of the normal vulvar architecture. The end result may mimic other diseases. Because cutaneous lichen planus is usually absent and oral disease may be asymptomatic, the diagnosis can be easily missed unless the clinician has a high index of suspicion. Although treatment for vulvar lichen planus is suboptimal, a correct diagnosis may end the patient's search for an answer and help to prevent unnecessary procedures and therapies.

Effect of oral isotretinoin on dysplastic nevi

We previously reported a favorable histologic response of dysplastic nevi to topical tretinoin in three patients. To investigate the anticancer and cancer preventive effects of retinoids we have examined the effect of systemic isotretinoin on dysplastic nevi. After confirmatory baseline biopsies, eleven patients with the dysplastic nevus syndrome were treated with oral isotretinoin, 40 mg twice a day for 4 months. At completion of therapy, at least three previously identified and photographed clinically typical dysplastic nevi were rephotographed and removed for histologic evaluation. Eight patients completed the full course of medication. There were no clinical changes in the dysplastic nevi in these patients. Posttherapy biopsy specimens in six volunteers revealed most of the remaining lesions to be dysplastic nevi. The majority of lesions biopsied in two subjects showed normal, benign nevi only. This proportion of clinically typical dysplastic nevi that prove to be normal nevi histologically (28%) is not significantly different from that reported by others. Oral isotretinoin does not appear to have a significant biologic effect on the clinical or histologic appearance of dysplastic nevi in the treatment schedule employed.

168 double J (pigtail) ureteric catheter insertions: a retrospective review

The medical records of 116 patients who had 168 ureteric double J (pigtail) catheters inserted over a 6-year period between 1981 and 1987 were reviewed. Eighty-five patients had pigtails inserted for benign conditions and 31 for malignant disease. The pigtail catheters were inserted cystoscopically in 88 patients, percutaneously in 7 patients and by open surgery in 21 patients. Of 168 pigtail catheters used, 147 were soft (silicone, multilength) and 21 hard (polyurethane). No mortality was attributable to the use of these catheters but certain complications were commonly encountered. Loin discomfort occurred after 32 (19%) insertions; 27 of 147 (18%) soft catheters and 5 of 21 (24%) hard catheters. Trigonal irritation, confirmed cystoscopically was reported in 26 of 147 (18%) insertions of soft catheters and in 6 of the 21 (29%) with hard catheters (chi 2, P = 0.37). Urinary tract infection (confirmed by urine microscopy and culture) occurred after 46 (31%) soft catheter insertions and after 13 of 21 (61%) hard catheter insertions (chi 2 test, P = 0.01). Stent migration occurred in five patients and obstruction in two. Pigtail catheters are safe ureteric stents which are easy to insert and their use is supported by this study. The complications of associated infection, trigonal irritation and loin discomfort are relatively common and still occur even with soft catheters. Careful monitoring of all patients with pigtail catheters in position is recommended.

Desquamative vaginitis: lichen planus in disguise

A principal cause of desquamative vaginitis is erosive lichen planus. We report five cases to illustrate the classic oral and vaginal findings, describe the histology, and relate the therapeutic response of the disease. Early recognition of the disorder and prompt use of corticosteroids and vaginal dilators may prevent the common sequelae of adhesion formation and vaginal stenosis.

Competition of milrinone, a non-iodinated cardiac inotropic agent, with thyroid hormone for binding sites on human serum prealbumin (TBPA)

Milrinone [2-methyl-5-cyano-(3,4'-bipyridin)-6(1H)-one] is a positive cardiac inotropic agent recently shown to have thyromimetic activity in vitro in a rabbit myocardial membrane Ca2+-ATPase system [K. M. Mylotte et al., Proc. natn. Acad. Sci. U.S.A. 82, 7974 (1985)]. In the present studies, milrinone was examined for activity as an inhibitor of iodothyronine binding by human serum thyroid hormone transport proteins, thyroxine-binding globulin (TBG), prealbumin (TBPA) and albumin. Polyacrylamide gel electrophoresis at pH 9.0 of sera equilibrated with [125I]thyroxine showed that milrinone competed with L-thyroxine (T4) for binding sites on TBPA (10 and 100 microM milrinone caused 61 and 73% reductions, respectively, in T4 binding to TBPA, P less than 0.01); T4 displaced from TBPA was bound by TBG and albumin. Comparable reductions in T4 binding to TBPA were observed in electrophoretic studies conducted at pH 7.4. Binding of triiodo-L-thyronine (T3) to TBPA was electrophoretically confirmed and shown to be decreased in the presence of milrinone. Electrophoresis of purified TBPA also demonstrated that [14C]milrinone co-migrated with this transport protein and that milrinone displaced tracer T4 from TBPA. Amrinone, the 2-H-5-NH2 analog of milrinone, had less than 5% of the activity of milrinone as an inhibitor of T4 binding in electrophoretic studies. Scatchard analysis of T4 and milrinone binding to purified TBPA, measured by equilibrium dialysis, showed two classes of binding sites, with association constants, respectively, of 6.1 X 10(7) M-1 and 1.6 X 10(6) M-1 for T4, and 1.7 X 10(6) M-1 and 8.9 X 10(2) M-1 for milrinone. Computer graphic modeling of the binding of milrinone to the T4 site in the crystal structure of TBPA showed that milrinone best occupied this site when the substituted bipyridine ring overlapped the phenolic ring of T4. In this orientation the 5-cyano group, which has an electronegativity similar to that of iodine, occupied the same volume as the 5'-iodine of T4. The 5-amino group of amrinone lacks these characteristics. In this orientation, the keto function of milrinone overlapped the T4 4'-hydroxyl and could participate in similar intermolecular interactions. Thus, milrinone, a non-iodinated bipyridine, and thyroid hormone share structural and biochemical homologies and compete for the same binding site on TBPA.

Scalp distribution of visual evoked potentials to foveal pattern and luminance stimuli

Scalp potentials elicited by pattern reversal, pattern onset, and flash stimulation have been studied in normal subjects by means of a 16-channel brain mapping system. In two groups of experiments the topography of the major positive component in each response was compared with 4 degrees full- and lateral half-field stimuli and, for more detailed exploration of the pattern components by M-scaled stimuli selected to activate 1 cm2-patches of striate cortex and associated extrastriate re-projections. The 4 degrees stimuli were found to elicit scalp distributions for the pattern reversal P100 and the pattern onset C1 consistent with striate and extrastriate visual cortical origins respectively. Data on the flash P2 component suggest that stimulation was not localized accurately; this may have been due to lateral spread of neural activity in the retina. Predictably, the M-scaled stimuli showed extensive inter- and intraindividual variations depending on stimulus type and location relative to fixation. The manner in which, in some subjects, the region of maximal activity on the map appears to migrate with change of stimulus position possibly reflects local retinotopic order in visual evoked potential generator areas. However, data are neither extensive nor detailed enough to be conclusive.

Donor age-dependent decline in response of human red cell Ca2+-ATPase activity to thyroid hormone in vitro

The effect of increasing donor age on the susceptibility of human red blood cell Ca2+-ATPase activity to stimulation in vitro by thyroid hormone was studied in 26 normal subjects, aged 15-81 yr. Basal enzyme activity (no added thyroid hormone) was unaffected by donor age. Group analysis, young (less than or equal to 50 yr) vs. elderly (greater than 60 yr old), revealed a 23% decrease in responsiveness of the enzyme to L-T4 (P less than 0.001). Regression analysis confirmed an age-dependent decline in thyroid hormone stimulability of Ca2+-ATPase [r = -0.42 (T4 effect) and -0.38 (T3 effect); P less than 0.01]. Red cell membrane Na,K-ATPase activity was not affected by donor age. Plasma T4 and T3 concentrations in these normal subjects also did not change with age. Possible contributions of the following mechanisms to this age-correlated change in enzyme activity were examined: altered responsiveness to calmodulin of membrane Ca2+-ATPase; membrane content of endogenous calmodulin, endogenous plasma T4 and T3 concentrations, and plasma glucose concentrations. Calmodulin responsiveness is required for iodothyronine action on the enzyme, but the calmodulin responsiveness of cells from elderly donors was not significantly different from that of cells from younger donors (P greater than 0.10). There was no relationship between membrane immunoassayable calmodulin and donor age or membrane calmodulin and Ca2+-ATPase activity. There were positive correlations between donor plasma T4 level and basal enzyme activity (P less than 0.05) and between donor plasma T3 concentration and hormone-responsive Ca2+-ATPase (P less than 0.01), but these did not contribute to the age effect. Plasma glucose previously was found to modulate red cell Ca2+-ATPase activity, but did not correlate with decreased hormone responsiveness of the enzyme in elderly donors. In conclusion, we found that the susceptibility of human red cell Ca2+-ATPase to in vitro thyroid hormone stimulation declined significantly with advancing donor age. Several possible calmodulin-dependent mechanisms for this age-dependent change were excluded, and thus, we postulate that the altered hormone sensitivity of the enzyme is membrane phospholipid mediated.

Orchiectomy versus long-acting D-Trp-6-LHRH in advanced prostatic cancer

One hundred and four patients were randomised for the study. Fifty-five were entered into the D-Trp-6-LHRH group and 49 into the orchiectomy group. All pre-treatment patient characteristics were similar and testosterone levels at 1 month or later were in the castrate range in both groups. Forty-six patients (83%) in the D-Trp-6-LHRH group and 40 (82%) in the orchiectomy group had a partial remission or stable disease at 3 months or later. There was no significant difference between the groups for response or survival. Three patients in the D-Trp-6-LHRH group had a disease "flare" in the first 10 days of treatment. The flare symptoms resolved by the end of 4 to 8 weeks. The incidence of flushing, decreased libido and impotence was similar in both groups. Although there was less psychological morbidity in the D-Trp-6-LHRH group the difference did not reach statistical significance. Our results indicate that long-acting D-Trp-6-LHRH offers a safe and highly effective alternative to orchiectomy.

Evidence for a retinal projection to the midbrain raphe of the cat

Nineteen abnormal temporomandibular joints (TMJs) imaged with high-field-strength surface-coil MR are presented to illustrate specific changes associated with disk derangement, trauma, and previous surgery. Cases were selected from a series of 248 TMJ MR studies in 144 patients (9–68 years old, 130 females and 14 males) performed during a 5-month period. Surgical findings were available for correlation in 44 of the 248 joints studied. Increased signal caused by myxoid degeneration within the degenerating meniscus was seen, as were pathologic changes including atrophy, fibrosis, and contracture of masticatory muscles occurring with internal degrangements. Advantages and limitations of MR are discussed with reference to arthrography and videofluoroscopy. High-resolution and partial-flip-angle images of a normal joint are provided for comparison.

In most clinical circumstances, MR is the procedure of choice when examining the TMJ, because it provides contrast resolution of soft-tissue structures superior to that of conventional imaging techniques.

Complementary components and local variations of the pattern electroretinogram

Pattern electroretinograms have been presumed to arise from a combination of luminance and pattern detection activities. Since the responses at low spatial frequencies are linearly related to contrast and contain negligible pattern specific components, it is proposed that a retinal illuminance response for higher spatial frequencies can be computed from the optical transfer function of the eye. These computed responses are subtracted from pattern electroretinograms to reveal a pattern-specific response with a marked bandpass characteristic. The peak spatial frequency of the bandpass curve declines with increasing peripheral angle. For central vision, the peak amplitude of the pattern-specific response is larger than the retinal illuminance response, but, in the peripheral retina, the two responses are found to be almost equal. The possible origins of these signals are discussed, and it is concluded that the technique provides a method of obtaining separated illuminance and pattern responses from retinal regions having different properties of spatial selectivity.

Role of topical tretinoin in melanoma and dysplastic nevi

The retinoids have been investigated extensively as chemopreventive and therapeutic agents in a variety of neoplasms. They have been shown to inhibit the proliferation of transformed cell lines in vitro and transplanted tumors in vivo. In cultured murine melanoma cells, retinoids inhibit proliferation and induce differentiation. Human melanoma cell lines have shown a mixed response. The clinical experience with retinoids in melanoma has been limited. Previously we investigated the activity of topical B-all-trans-retinoic acid (Retin-A, vitamin A acid, retinoic acid, and tretinoin) against intracutaneous metastases from malignant melanoma. We saw complete remission of multiple lesions in one individual and regression of several lesions in a second patient. This experience led us to conduct the present pilot trial of topical tretinoin in dysplastic nevus syndrome. The latter is a precursor of malignant melanoma. We saw regression of some of the treated lesions to benign nevi showing minimal or no dysplasia. Thus topical tretinoin appears to possess some activity against melanoma and at least one of its precursor conditions. In view of these preliminary results, more extensive trials are warranted to better define the role of tretinoin in the chemoprevention of malignant melanoma in high-risk lesions.