Teledermatology in Atopic Dermatitis: A Systematic Review

Telemedicine use has been increasing especially during the COVID-19 pandemic. Various studies have outlined benefits of telemedicine including improving health equity, reducing wait times, and cost-effectiveness. Skin diseases such as atopic dermatitis (AD) may potentially be managed via telemedicine. However, there are no evidence-based recommendations for best practices in telemedicine for assessing AD patients. The objective of this review is to assess and summarize current evidence on telemedicine modalities for AD. This review will assess patient outcomes from various telemedicine models for AD. A review protocol was developed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement. Two reviewers independently screened potential studies and extracted data. Studies were included if they evaluated any telemedicine assessment for AD. Of 2719 identified records, 5 reports were included. Two reports used the direct-access online model, 1 used web-based consultation, 1 used e-health through a personal eczema portal, and 1 used an online platform and mobile application. All models were variations of the asynchronous, store and forward model. In all the included reports, teledermatology for the follow-up of patients with AD was effective and equivalent when compared to in-person appointments or standard treatment for their respective key outcome measures. However, it is unclear what the most effective teledermatology model is due to significant heterogeneity between studies. Teledermatology may serve as an important tool for triaging and follow-up of patients with AD. More studies are needed to determine which teledermatology models are most effective for virtual assessment of AD.

A case report of therapeutically challenging chronic actinic dermatitis

Chronic actinic dermatitis is a difficult to treat photodermatitis. Treatment is not standardized and involves topical corticosteroids and immunomodulators, and systemic immunosuppressive agents. We present a case with partial response to dupilumab, a monoclonal antibody approved for atopic dermatitis. In recalcitrant cases, systemic agents such as methotrexate, azathioprine, mycophenolate mofetil, and thalidomide, extracorpeal electrophoresis, and low-dose psoralen and ultraviolet A can also be considered.

Aesthetic Dermatologic Surgery Training in Canadian Residency Programs

BACKGROUND:

The public and other physicians expect dermatologists to be experts on aesthetic dermatology services. In Canada, current challenges may limit residents from achieving competency in aesthetic dermatology during their training. This may adversely affect patient safety, create medicolegal risks, and deter graduates from offering aesthetic procedures.

OBJECTIVES:

The objective of this article is to characterize the curriculum, hands-on learning opportunities, and perceptions of aesthetic dermatologic training in Canadian dermatology residency training programs.

METHODS:

An online survey of faculty and residents within Canadian dermatology residency programs was performed. The main outcome measures were the hours of formal aesthetic dermatology teaching, the frequency of hands-on dermatology resident training with injectables and devices, and comparing faculty and resident perspectives regarding resident aesthetic dermatology training.

RESULTS:

Thirty-six faculty members (40%) and 47 residents (34%) responded to the survey. Lasers, fillers, neuromodulators, and mole removal were most commonly taught in the 10 hours or fewer of formal instruction. Residents commonly observed rather than performed procedures. High dissatisfaction among residents was reported with the quality and quantity of aesthetic dermatology training. Faculty and resident respondents supported increasing aesthetic dermatology education, and approximately 70% of residents plan to offer aesthetic services. Discounted pricing or resident-led clinics were felt to be ways to increase resident hands-on experience.

CONCLUSIONS:

The standardization of core competencies in aesthetic dermatologic procedures is essential to ensure patient safety and practitioner competence. At present, formal aesthetic dermatology training in residency may be insufficient for hands-on training. The majority of dermatology faculty and resident respondents support increasing aesthetic dermatology training.

Persistency of Biologic Therapies for Plaque Psoriasis in 2 Large Community Practices

BACKGROUND

Biologics have transformed the management of moderate to severe psoriasis. The persistency of biologics lacks real-world data.

OBJECTIVES

To quantify drug survival of infliximab (IFX), adalimumab (ADA), etanercept (ETA), and ustekinumab (UST) and to identify potential factors affecting drug survival.

METHODS

An observational, retrospective 2-centre study consisting of 906 patients from private practices in Ontario between July 2003 and June 13, 2016, was conducted, including patients with plaque psoriasis receiving commercial treatment with ADA, ETA, IFX, and UST. Paper and electronic records of each patient were reviewed.

RESULTS

Median survival times for UST, IFX, ADA, and ETA were respectively, in months, 68, 23, 33, and 28. Female sex was determined to be a statistically significant positive predictor of drug survival. Our study was consistent with the literature in that UST had the highest survival rate compared to the other biologics, and the shape of our drug survival curve suggested that loss of drug efficacy is a stochastic occurrence. Compared to other studies, our data exhibited lower survival rates at various time points for all the biologics studied, and female sex did not predict drug survival in other studies. We also investigated potential reasons for differences in biologic survival times between different practices; the main differentiator was drug dosage, as higher dosages were associated with greater survival.

CONCLUSION

UST has a higher drug survival rate than ADA, ETA, and IFX, as observed in other studies. When practice patterns are compared, dosage difference is the main factor that may cause differing survival rates.

Experimental Study of the Pathogenicity of Pasteurella multocida Capsular Type B in Rabbits

The increased frequency of isolation of Pasteurella multocida capsular type B from rabbitries in north-western India prompted this investigation into the role of this organism in inducing disease in rabbits. Ten rabbits were divided into two groups of five animals. Group I rabbits were infected intranasally (IN) with 1 ml of inoculum containing 2 × 10(5) colony forming units/ml, while rabbits in group II were given 1 ml phosphate buffered saline IN. The rabbits in group I developed respiratory distress, increased rectal temperature and severe dyspnoea, with death occurring 24-48 h post infection. The main pathological findings were severe congestion and haemorrhage in the trachea, fibrinopurulent pneumonia, bacteraemia and septicaemia. The nasal secretions of all group I animals contained P. multocida. These observations indicate that in addition to P. multocida capsular types A and D, P. multocida capsular type B can also be highly pathogenic for rabbits.

Development of OMP based indirect ELISA to gauge the antibody titers in bovines against Pasteurella multocida

Pasteurella multocida (P. multocida) is an important pathogen of various domestic animals. The outer membrane proteins (OMPs) play a major role in pathogenesis and immunogenicity of P. multocida. The aim of the study was to develop indirect enzyme linked immuno sorbant assay (ELISA) based on OMPs to ascertain the antibody titers in animals post-infection or to gauge the potency of vaccine. The OMPs were extracted and purified from P. multocida P:52 (vaccine strain) and P. multocida B:2 isolated from natural outbreak of Haemorrhagic septicaemia (HS) and analyzed on SDS PAGE and through western blot. The OMPs profile of the vaccine strain and the isolate from the natural outbreak of HS were found to be similar. Optimization of various components viz. coating antigens, anti-species conjugate, etc. were carried out against both anti-P. multocida hyper immune and pre immune serum. Validation of OMP based indirect ELISA assay to measure immune response against P. multocida in bovine revealed 91% diagnostic sensitivity (DSN) and about 100% diagnostic specificity (DSP) at 25% cut off. OMP based indirect ELISA was found to be more specific, but less sensitive as compared to WCL based assay.

Bifid mandibular condyle with temporomandibular joint ankylosis: report of two cases and review of literature

Bifid mandibular condyle is an uncommon entity with a controversial etiology. It can be developmental or acquired and rarely may be associated with temporomandibular joint (TMJ) ankylosis. Although the patient may be asymptomatic, the radiologist should be aware of this entity and its clinical implications. We report two cases of BMC, one developmental and the other secondary to trauma. Both were diagnosed using computed tomography, which additionally revealed the associated ankylosis of TMJ in both the patients.

Various methods of caries removal in children: a comparative clinical study

An in vivo study comparing the different methods of caries removal was done in children of age group 6-9 years. Among these patients a total number of 150 carious deciduous teeth were selected. Caries removal was done by hand instruments, airotor and carisolv. The efficacy, time taken and pain experienced by the patient during caries removal was evaluated. The results showed that airotor was the most efficient method (mean value 0.38), while carisolv was the least painful (mean value 0.080) and the most time consuming method (534.8 seconds).

Choroidal detachment following retinal detachment surgery: an analysis and a new hypothesis to minimize its occurrence in high-risk cases

PURPOSE

To determine factors predisposing to the development of choroidal detachment following conventional retinal detachment surgery, to evaluate its clinical course, and to identify possible measures to reduce its occurrence.

METHODS

Analysis of 25 consecutive cases of choroidal detachment following retinal detachment surgery out of a total of 510 cases undertaken at a tertiary care referral eye center over a period of 15 months.

RESULTS

The incidence of developing choroidal detachment was 4.9%. The mean age was 61 years (range 28 to 76 years) and there was no sex predilection. Hypertension was present in 16% (n=4). A total of 44% (n=11) of patients had myopia and with respect to the lens status, 44% (n=11) were phakic, 36% (n=9) were pseudophakic, and 20% (n=5) were aphakic. Redetachment of the retina was observed in 12% (n=3) of cases. Elevated intraocular pressure developed in 12% (n=3). In one patient with an anterior chamber intraocular lens and "kissing" choroidal detachment, drainage of the choroidals was undertaken to prevent corneo-lenticular touch and corneal decompensation. In two patients with redetachment, anatomic settlement of the retina was achieved only following vitreoretinal surgery.

CONCLUSIONS

The following preoperative and intraoperative factors are associated with a significantly increased risk of choroidal detachment following retinal detachment: higher age, myopia, posteriorly placed explants even if its extent is less, anteriorly placed explants whenever its extent is large, drainage of subretinal fluid, and intraoperative hypotony. Choroidal detachment may also occur in patients with only a radial sponge. Designing a notch intraoperatively in the region of the explants overlying the vortex veins may help to reduce the risk of choroidal detachment following conventional retinal detachment surgery.

LASIK after retinal detachment surgery

AIM

To assess the efficacy and safety of laser in situ keratomileusis (LASIK) for correction of myopic refractive errors in eyes which have previously undergone retinal detachment surgery.

METHODS

In a prospective, non-comparative case series, 10 eyes of nine patients who had a myopic refractive error and had previously undergone retinal detachment surgery underwent LASIK surgery according to the standard surgical protocol. The surgery could be completed in eight eyes and in two eyes it was aborted intraoperatively. The parameters evaluated included the uncorrected visual acuity, best corrected visual acuity, refraction, detailed fundus evaluation with indirect ophthalmoscope, slit lamp biomicroscopy, and corneal pachymetry. Any intraoperative or postoperative complications were recorded. Follow up visits were scheduled at day 1, 1 week, 1 month, 3 months, and 6 months after LASIK.

RESULTS

Eight eyes underwent successful LASIK surgery. The mean spherical equivalent before surgery was -5.436 (SD 1.6) dioptres (D), which was reduced to +0.42 (0.65) D, -0.07 (1.32) D, -0.06 (1.39) D, and -0.06 (0.65) at 1 week, 1 month, 3 months, and 6 months respectively after LASIK. The uncorrected visual acuity improved in all the eyes and the best corrected visual acuity improved or remained same in all the eyes. There was no retinal complication after LASIK.

CONCLUSION

LASIK may be used to correct refractive errors in eyes that have undergone retinal detachment surgery. However, scarred conjunctiva in such cases may prevent generation of optimal suction for the microkeratome.

Posterior vitreous wick syndrome: a potential cause of endophthalmitis following vitreo-retinal surgery

Endophthalmitis following pars-plana procedures such as a vitrectomy vitreo-retinal procedures has been infrequently reported in literature. The cited incidence is about 0.1% to 0.2%. In the 8 cases of endophthalmitis that have been reported in literature, the prognosis has been indicated as very poor due to a delay in diagnosis (1-3). Also, no possible source of an inoculum of the pathogenic organism reaching the vitreous cavity has been considered in these reports. We have encountered a few cases of endophthalmitis following vitreo-retinal surgeries at our tertiary eye care centre. Here again not being able to identify the possible source of infectious spread, we now report for the first time in literature, a new entity, the 'posterior vitreous wick syndrome'. This potential source of infectious spread, to the best of our knowledge, has not been considered earlier. We describe the patho-mechanism of the 'posterior vitreous wick syndrome' and also suggest methods of reducing its occurrence during vitreo-retinal procedures. This could also be the patho-mechanism of endophthalmitis following inadvertent loss of scleral integrity during extraocular surgeries like retinal detachment surgery and strabismus surgery (4,5).

Phototoxic retinopathy

Although the occurrence of iatrogenic light-induced retinal toxicity is beyond doubt, several issues remain to be studied further. These include conflicting reports regarding the wavelength of light that is most hazardous; what mechanism contributes more significantly in the pathogenesis of light-induced retinal toxicity-photochemical or photothermal; why does it occur in only some patients; and what is the protective role of UV absorbing chromophores in intraocular implants. Nevertheless, it is important for all ophthalmic surgeons to be aware of this complication and take measures that could decrease the risk of its occurrence.

Comparative study of vitrectomy for dropped nucleus with and without the use of perfluorocarbon liquid. Clinical, electrophysiological and visual field outcomes

PURPOSE

To compare pars plana vitrectomy for dropped nucleus with and without perfluorocarbon liquid.

METHODS

24 eyes with dropped nucleus were randomized to undergo PPV with perfluorodecalin, (study, n=12) and without it (control, n=12). Visual acuity, IOP, visual evoked response and electroretinography were noted at study entry and up to 3 months after PPV. Humphrey perimetry was done at 3 months.

RESULTS

Final visual acuity was >20/60 in 75% of study eyes and 41.6% of controls. The two groups were statistically comparable with regard to the above parameters before PPV and during follow-up. The timing of vitrectomy did not significantly influence the final visual acuity. A higher rate of complications was seen in the control group.

CONCLUSIONS

Perfluorodecalin facilitated the procedure and possibly minimized complications, and was found to be safe for intraoperative use in terms of recovery of visual acuity, stable ERG and VER, and normal visual fields.

Antioxidants: Basis concepts in relation to the eye

Antioxidants are a small group of substances that protect living cells from the destructive consequences of powerful oxidizing intermediates that can be formed from oxygen. Situations in which pro-oxidant mechanisms within the body are more active than the antioxidant mechanisms (oxidative stress) predispose and contribute to the pathogenesis of several ailments in various organs of the body. In the eye, pro-oxidant factors have been blamed for the causation of diseases such as age related macular degeneration and senile cataract. The role of pro-oxidants in the genesis of certain diseases is well established however, the effectivity of antioxidants provided to the body by dietary supplementation is inconclusive. In this article we provide a review on the basic concepts of antioxidant-pro-oxidant interaction in relation to its effects on the eye.

New approaches in the management of choroidal neovascular membrane in age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly population. The prevalence is reported to be 1.2-1.4% in several population-based epidemiological studies. Currently 25-30 million people worldwide are blind due to AMD. With the aging world population it is bound to increase significantly, and could become a significant public health problem in next two decades, with serious socio-economic implications. Several strategies are today available to treat the wet form of AMD, which is responsible for significant visual loss. These were until recently confined to laser photocoagulation, and subretinal surgery, but today two other modalities, namely, radiation and photodynamic therapy, are available. These treatment modalities however, are aimed at preservation of vision only, and not at reversing the process of the disease. Further research on antiangiogenic drugs and gene therapy could significantly help AMD patients.

Combined hamartoma of the retina and retinal pigment epithelium with full thickness retinal hole and without retinoschisis

Combined hamartoma of the retina and retinal pigment epithelium has been described as a rare, benign tumor formed by an overgrowth of several constituents of the retina such as the retinal pigment epithelial cells, vascular elements, and glial components.1 Despite its varied clinical appearance it is important to recognize this tumor as it is known to simulate intraocular malignancies like retinoblastoma and choroidal melanoma.

Osseous choristoma of the choroid

Osseous choristoma of the choroid, also called choroidal osteoma, is a very rare and unusual form of intraocular ossification. We report a case of choroidal osteoma in a young healthy male that to the best of our knowledge is the first report from India.

Comparative evaluation of early vs. deferred vitrectomy in Eales' disease

METHODS

40 cases of vitreous haemorrhage secondary to Eales' disease were taken up for vitrectomy. Depending upon duration of vitreous haemorrhage patients were divided into two groups: Group I (20 eyes) - early vitrectomy group with duration between 3-6 months; Group II (20 eyes) - deferred vitrectomy group with duration of more than 6 months. All patients were followed up for a minimum period of 3 months following vitrectomy.

RESULTS

Eyes in Group I showing a preoperative ultrasonic picture of complete posterior vitreous detachment, less mobility of organised vitreous haemorrhage and mid vitreous organisation on kinetic echography achieved a final visual acuity of 6/9 or better in 13 (65%) eyes as compared to 4 (20%) eyes in Group II (p<0.01). Poor visual outcome in the deferred group was secondary to cystoid macular oedema, macular scar, macular pucker formation and macular degeneration.

CONCLUSION

Improved visual outcome in the early vitrectomy group was probably because the haemorrhagic blood and its toxic products had less time to damage the macula, a lesser incidence of macular traction and cystoid macular oedema.

Mononucleotide microsatellite instability and germline MSH6 mutation analysis in early onset colorectal cancer

Germline mutations in the MSH2 and MLH1 mismatch repair genes account for most cases of hereditary non-polyposis colon cancer syndrome (HNPCC). In addition, germline MSH2 and MLH1 mutations have been detected in patients with non-HNPCC early onset colorectal cancer. Germline MSH6 mutations appear to be rare in classical HNPCC families, but their frequency in young colorectal cancer cases has not been studied previously. In a population based study of early onset colorectal cancer (<50 years) investigated for tumour microsatellite instability (MSI), we identified a subgroup of tumours with MSI for mono- but not dinucleotide repeat markers (m-MSI+ group). In contrast to tumours with classical MSI for dinucleotide markers (d-MSI+), the m-MSI+ group cancers were mainly left sided (6/7). As MSH6 mutations in yeast and human cell lines are associated with weak (and preferential mononucleotide) MSI, the complete MSH6 gene coding region was sequenced in blood DNA from the five m-MSI+ cases available for analysis. A germline nonsense mutation was identified in an isolated case of early onset colorectal cancer (age 43 years). These results support previous findings that germline MSH6 mutations may not be associated with classical MSI and suggest a role for germline MSH6 mutations in isolated early onset colorectal cancer.

Combined central retinal artery and central retinal vein occlusion following pars plana vitrectomy

Combined occlusion of the central retinal artery and central retinal vein is an infrequently encountered clinical entity. Although there are reports in the literature of a combined occlusion of the central retinal artery and vein, its occurrence following pars plana vitrectomy has not been described. We report the case of an elderly patient who developed this unusual occurrence following an uneventful pars plana vitrectomy for a posteriorly dislocated IOL.

Surgical removal of a free floating cyst of the iris pigment epithelium causing disturbing visual symptoms

Pigmented cysts in the anterior chamber, fixed or free floating, are considered to be unusual but not very infrequent. However, most of these cases usually do not need any treatment other than a periodic observation. We report the surgical removal of an iris pigment epithelial cyst floating freely in the anterior chamber. The reason for surgical removal was, disturbance in near vision being caused by movement of the cyst across the visual axis. This specific symptom of disturbed near vision, to the best of our knowledge, is a rare indication for surgery that has not been pointed out earlier. Histopathological confirmation of the clinical diagnosis was also obtained.

Optic neuritis following albendazole therapy for orbital cysticercosis

PURPOSE

To report the occurrence of optic neuritis following oral albendazole therapy for orbital cysticercosis.

METHODS

Two patients having definitively diagnosed orbital cysticercosis at the orbital apex developed an acute visual loss 1 week after initiation of oral albendazole. Ultrasonography and magnetic resonance imaging determined that the cause was optic neuritis due to disorganization of the cyst with inflammation of the adjacent optic nerve.

RESULTS

Oral corticosteroids (prednisolone 1 mg/kg per day) given for a period of 4 weeks led to resolution of the optic neuritis, with full visual recovery.

CONCLUSION

Corticosteroids should be given in addition to albendazole in the treatment of orbital cysticercosis when cysts are in close proximity to the optic nerve.

Rapid and simple prenatal DNA diagnosis of Down's syndrome

BACKGROUND

Prenatal diagnosis of chromosomal abnormality requires cytogenetic analysis of amniotic fetal cells. The necessary culture time delays diagnosis, is expensive, and requires substantial scientific expertise. In a masked prospective study, we investigated the feasibility of PCR amplification of chromosome 21 markers for the prenatal diagnosis of Down's syndrome.

METHODS

The study population consisted of 2167 pregnant women, undergoing amniocentesis for prenatal diagnosis. In this cohort at least 1.5 mL amniotic fluid was available surplus to the requirements for traditional diagnostic methods. DNA was extracted from the surplus amniotic fluid and amplified in fluorescence-based PCR reactions, with three small-tandem-repeat markers located on chromosome 21. The products of the reactions were analysed on a DNA sequencer to identify the presence of two or three copies of chromosome 21.

FINDINGS

In 2083 (97.4%) of 2139 samples of amniotic fluid that were not macroscopically blood-stained, two DNA markers gave an informative and correct result, identifying 2053 fetuses as normal and 30 as having trisomy 21 Down's syndrome (as confirmed by cytogenetic analysis). An extra marker was informative in 32 of 41 other clear samples. Thus a total of 99.6% informative results was achieved with these three markers. Macroscopically blood-stained samples (28 [1.3%]) were unsuitable for DNA testing. They gave a typical but non-informative result. There were no false-positive or false-negative results.

INTERPRETATION

The PCR-based DNA diagnostic test has great potential for improved prenatal diagnosis of Down's syndrome, with the advantage that results may be available within a day.

Efficacy of diode laser for managing diabetic macular oedema

PURPOSE

To evaluate the effect of photocoagulation for diabetic macular oedema using Diode laser in a prospective randomized fashion and comparing its effects with the Argon green laser.

METHODS

40 eyes with focal and diffuse oedema were randomly treated with Diode and 40 eyes were treated with Argon green. Following investigations were performed: visual acuity, fundus evaluation, flourescein angiography and visual fields.

RESULTS

79% treated with Diode had partial to complete regression of oedema and so also 82% with Argon green at six months post laser.

CONCLUSIONS

There was no difference in improvement or worsening of visual acuity between the two lasers. This study is of importance as it has been the first prospective randomized study of its kind using Diode laser in diabetic macular oedema.

Retinopathy after solar eclipse, 1995

BACKGROUND

Visual damage following direct sighting of the solar eclipse is a well established clinical entity. In spite of warnings in the media, a number of people attempted to observe the solar eclipse. Consequently, some developed visual damage.

METHODS

Twenty-one patients were referred to the Solar Eclipse Cell at our centre. Their demographic and clinical features were evaluated.

RESULTS

Foveal findings correlated with the duration of exposure and frequency of watching the eclipse. Six patients had used protective devices for viewing the eclipse. More than 47% eyes had discernible fundus lesions.

CONCLUSION

Lasting visual damage can follow a solar retinal burn with little or no protection from the viewing devices. Prevention remains the best treatment and there is a need to educate the public in this regard.

A follow-up study on visual outcome after camp-based intracapsular cataract extraction

The visual outcome of 164 intracapsular cataract extractions (ICCE) performed in 158 patients at an eye-camp was evaluated. 93.3% had a preoperative visual acuity of less than 3/60. On the 4th/5th post-operative day, 39.3% had a visual acuity between 6/18 and 6/36; 84.7% had vision better than 3/60. Six weeks post-operatively, 44.1% had visual acuity better than 6/18 and a total of 84.1% better than 3/60. The vision of 40.7% improved between the 4th/5th post-operative day and the follow-up visit at 6 weeks. 46.4% of patients had post-operative corrected visual acuity better than 6/18, 24.3% had vision between 6/18 and 6/36, and a total of 84.3% had vision better than 3/60. The patients' satisfaction in terms of improvement in mobility and ability to do housework at 6 weeks after the operation correlated better with the improvement in vision in terms of the number of Snellen's lines than with the actual post-operative visual acuity.

Major histocompatibility complex class I expression on neurons in subacute sclerosing panencephalitis and experimental subacute measles encephalitis

Lack of major histocompatibility class I antigens on neurons has been implicated as a possible mechanism for viral persistence in the brain since these antigens are required for cytotoxic T-lymphocyte recognition of infected cells. In subacute sclerosing panencephalitis (SSPE), measles virus (MV) persists in neurons, resulting in a fatal chronic infection. MHC class I mRNA expression was examined in formalin-fixed brain tissue from 6 SSPE patients by in situ hybridization. In addition MHC class I protein expression in MV-infected neurons was examined in experimental Subacute Measles Encephalitis (SME) by double immunohistochemistry. MHC class I mRNA expression was found to be upregulated in SSPE tissues studied, and in 5 out of 6 cases the expression was definitively seen on neurons. The percentage of neurons expressing MHC class I mRNA ranged between 20 to 84% in infected areas. There was no correlation between the degree of infection and expression of MHC class I molecules on neurons. Importantly, the number of neurons co-expressing MHC class I and MV antigens was markedly low, varying between 2 to 8%. Similar results were obtained in SME where 20 to 30% of the neurons expressed MHC class I but <8% co-expressed MHC class I and MV antigens. Perivascular infiltrating cells in the infected regions in SME expressed IFNgamma immunoreactivity. The results suggest that MV may not be directly involved in the induction of MHC class I on neurons and that cytokines such as IFNgamma may play an important role. Furthermore, the paucity of neurons co-expressing MHC class I and MV antigens in SSPE and SME suggests that such cells are either rapidly cleared by cytotoxic T lymphocytes (CTL), or, alternatively, lack of co-expression of MHC class I on MV infected neurons favors MV persistence in these cells by escaping CTL recognition.

Plasticity in the adult human oligodendrocyte lineage

Preoligodendrocytes have been described in cultures and tissue prints of adult human white matter (Armstrong et al., 1992). To characterize further these precursors of human oligodendrocytes, we have investigated whether they express genes playing a critical role in oligodendrocyte development. In the intact human brain, platelet-derived growth factor receptor alpha (PDGF alpha R) and myelin transcription factor 1 (MyTI) transcripts are expressed in 1-2% of cells of the oligodendrocyte lineage (OL), and clusters of such cells can be found in the periventricular region. Myelin basic protein transcripts containing exon 2 information (exon 2+ MBP), which are characteristic of the premyelinating stage, are detected in 15-20% of OL cells in vivo. When OL cells are separated from human white matter and allowed to regenerate in vitro, a much larger proportion of these cells express developmentally regulated genes, while exon 2- MBP and proteolipid protein (PLP) transcripts characteristic of mature OL cells appear transiently downregulated. Basic fibroblast growth factor (bFGF), even in the presence of PDGF, does not promote DNA synthesis in these cultured OL cells. Yet bFGF induces human oligodendrocytes to regenerate their processes rapidly in vitro and to express O4 antigens as well as exon 2+ MBP, MyTI, and PLP transcripts. While bFGF accelerates early regenerative processes, it also maintains high expression of exon 2+ MBP transcripts in OL cells for up to 2 weeks in vitro. In contrast, high levels of insulin in the absence of bFGF allow accumulation of exon 2- MBP and PLP transcripts in most OL cells at 2-3 weeks in vitro. We propose that the myelinated human brain harbors a small pool of precursors of oligodendrocytes and that growth factor-regulated phenotypic plasticity rather than mitogenic potential accounts for the regeneration of oligodendrocytes in the initial stages of demyelinating diseases such as multiple sclerosis.

Evaluation of an innovative school eye health educational mode

An innovative mode of using school children as health educators for transmitting messages on eye health care in the school environment was evaluated. Fifty children were evaluated at baseline and immediately after the educational session. A significant change in cognitive aspects of eye care was demonstrated (p < 0.001). Knowledge on vitamin A related aspects and childhood ocular trauma improved substantially compared to all other aspects of eye care.

Eye casualty department

A retrospective analysis of all new patients attending our eye casualty department was carried out during the 1 year period, from January to December 1987. During this time the casualty unit saw and treated 4905 new patients. Of these 40.61% were traumatic in origin, 30.52% comprised various ocular infections and the remaining 28.87% had miscellaneous ocular problems. On average, 13 new patients and seven consultations from other departments were seen and treated daily. Apart from the management of ocular emergencies, other functions provided by our department included glaucoma screening, donor eye collection, attending to referrals from other departments and eye health education.

Ocular ethambutol toxicity: is it reversible?

Delayed onset ocular ethambutol toxicity is usually considered to be reversible following prompt withdrawal of the drug. However, in a series of seven consecutive patients with severe visual deficit due to ethambutol toxicity, only 42.2% (3 of the 7 patients) achieved a visual recovery of better than 20/200 after an average follow-up of 8.3 +/- 2.1 months after stoppage of the drug. On fluorescein angiography, three cases (42.2%) progressed to optic atrophy during the follow-up with permanent visual damage. There were no predisposing or risk factors to contribute toward the poor visual gain. In this background, we recommend discontinuation of ethambutol from the antituberculous regimen. As an additional sidelight, the value of visually evoked potential in the monitoring of patients on ethambutol, especially in cases with early periaxial neuritis, has been emphasised.

Peribulbar anesthesia in retinal reattachment surgery

We prospectively evaluated the effectiveness of peribulbar anesthesia in retinal reattachment surgery. Of the 24 patients studied, 2 required retrobulbar supplementation during the latter part of the surgery. Our results show that peribulbar anesthesia can be effectively used for retinal reattachment surgery and probably should be the preferred form of local anesthesia for this surgery, since the eyes involved have a relatively high incidence of axial myopia and posterior staphyloma.

Echographic measurement of extraocular muscle thickness in proptosis

Echographic extraocular muscle thickness was measured in 102 eyes of 51 patients with proptosis of varied etiology. That of vascular origin was associated with extraocular muscle enlargement in all cases. Enlargement of the medial rectus was found to be statistically significant in thyroid orbitopathy. Sixty percent of cases with nonspecific orbital inflammatory disease had enlarged extraocular muscles. We discuss the supportive role of determining echographic measurements of extraocular muscle thickness in proptosis and highlight the uniform extraocular muscle enlargement found in proptosis of vascular origin.

Cryopexy in pars planitis

Cryotherapy has been reported to be of benefit in pars planitis. We studied 16 eyes with classic pars planitis unresponsive to corticosteroid therapy. Eight eyes continued with systemic and periocular steroid therapy, and in the remaining eight eyes transconjunctival cryopexy of the peripheral retina and vitreous base was done as an additional procedure. At 6 months four of the eyes that received cryopexy showed an improvement in Snellen visual acuity, and in the other four the acuity was unchanged; none of the eyes showed any vitreous base neovascularization. Among the eyes that received steroid therapy only, the acuity was unchanged in five, improved in one and reduced in two.

Peribulbar anesthesia and optic nerve conduction

Serial recordings of distance visual acuity and visually evoked potentials (VEPs) after peribulbar anesthesia in three patients are reported. Visual acuity was not markedly affected but the latency and amplitude of VEPs were. This study concludes that optic nerve conduction is not significantly affected by peribulbar anesthesia.

Iris neovascularization in Sturge-Weber syndrome

An unusual case of Sturge-Weber syndrome with raised intraocular pressure is presented. The slit lamp examination and anterior segment fluorescein angiography were consistent with iris neovascularization. Cause and effect relationship of iris neovascularization with glaucoma in this syndrome is discussed.