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Biomedical subjects

A Hennig

Publications and source records attributed to A Hennig.

At least 19 recordsLinked to original sources
PubMed2004

Contact angle hysteresis: study by dynamic cycling contact angle measurements and variable angle spectroscopic ellipsometry on polyimide.

The phenomenon of contact angle hysteresis was studied on smooth films of polyimide, a polymer type used in the microelectronic industry, by dynamic cycling contact angle measurements based on axisymmetric drop shape analysis-profile in combination with variable angle spectroscopic ellipsometry (VASE). It was found that both advancing and receding contact angles became smaller with increasing the number of cycles and are, therefore, not a property of the dry solid alone. The changes of the wetting behavior during these dynamic cycling contact angle measurements are attributed mainly to swelling and/or liquid retention. To reveal the water-induced changes of the polymer film, the polyimide surface was studied before and after the contact with a water droplet by VASE. Both the experimental ellipsometric spectrum for Delta and that for Psi as well as the corresponding simulations show characteristic shifts due to the contact with water. The so-called effective medium approximation was applied to recover information about the thickness and effective optical constants of the polymer layer from the ellipsometrically measured values of Delta and Psi. On the basis of these results, the swelling and retention behavior of the polyimide films in contact with water droplets were discussed.

Journal Article↗
PubMed2004

[Stenosing gastric laryngitis in infancy].

A 2 month old female infant presented an aphonic voice and increasing inspiratory stridor due to a stenosing granulating laryngitis. A pathologically elevated gastroesophageal reflux was measured by means of 24-h pH-metry. After antireflux therapy (Cisaprid, sodium alginate and upright body positioning), the laryngitis was completely healed. This case confirms that an elevated gastroesophageal reflux in infants can cause chronic inflammatory diseases of the upper respiratory tract, especially of the larynx.

Alginates↗
PubMed2003

Sutureless cataract surgery with nucleus extraction: outcome of a prospective study in Nepal.

AIM: To report the short and medium term outcome of a prospective series of sutureless manual extracapsular cataract extractions (ECCE) at a high volume surgical centre in Nepal. METHODS: Cataract surgery was carried out, on eyes with no co-existing diseases, in 500 consecutive patients who were likely to return for follow up. The technique involved sclerocorneal tunnel, capsulotomy, hydrodissection, nucleus extraction with a bent needle tip hook, and posterior chamber intraocular lens (PC-IOL) implantation according to biometry findings. Surgical complications, visual acuity at discharge, 6 weeks, and 1 year follow up, and surgically induced astigmatism are reported. RESULTS: The uncorrected visual acuity at discharge was 6/18 or better in 76.8% of eyes, and declined to 70.5% at 6 weeks' follow up, and 64.9% at 1 year. The best corrected visual acuity was 6/18 or better in 96.2% of eyes at 6 weeks and in 95.9% at 1 year. Poor visual outcome (<6/60) occurred in less than 2%. Intraoperative complications included 47 (9.4%) eyes with hyphaema, and one eye (0.2%) with posterior capsule rupture and vitreous in the anterior chamber. Surgery led to an increase in against the rule astigmatism, which was the major cause of uncorrected visual acuity less than 6/18. Six weeks postoperatively, 85.5% of eyes had against the rule astigmatism, with a mean induced cylinder of 1.41 D (SD 0.8). There was a further small increase in against the rule astigmatism of 0.66 D (SD 0.41) between 6 weeks and 1 year. The mean duration of surgery was 4 minutes and the average cost of consumables, including the IOL, was less than $10. CONCLUSION: Rapid recovery of good vision can be achieved with sutureless manual ECCE at low cost in areas where there is a need for high volume cataract surgery. Further work is required to reduce significant postoperative astigmatism, which was the major cause of uncorrected acuity less than 6/18.

Aged↗
PubMed2002

[Morphological and functional results of Palisade Cartilage Tympanoplasty].

BACKGROUND AND OBJECTIVE: The application of cartilage in tympanoplasty has been generally accepted, because cartilage as a bradytrophic tissue allows stable and functionally reliable reconstruction of the eardrum even in difficult pathological conditions (such as subtotal defects, tympanosclerosis etc.). A special surgical technique using small cartilaginous chips for the reconstruction of the eardrum has been developed by J. Heermann, who introduced it as Palisade Cartilage Tympanoplasty (PCT). Although being increasingly applied in otosurgery, this technique has to date neither been evaluated regarding morphological and hearing results nor regarding its combination with titanium ossicular reconstruction prostheses. PATIENTS AND METHODS: Therefore we reviewed 84 of 94 ears (92 patients, 58 female, 34 male) 12 to 36 months after PCT. RESULTS: A recurrent defect was seen in 2 ears (1 adhesive otitis, 1 subtotal defect). There were no extrusions of prostheses. Preoperatively an ear-bone-gap of 0-10 dB was seen in 2 ears, 11-30 dB in 48 and 31-59 dB in 34 ears. Postoperatively the corresponding numbers were 25, 50 and 9 ears. CONCLUSIONS: The low rate of recurrent tympanic membrane defects (2.4%) shows that palisade cartilage tympanoplasty is particularly appropriate for the management of difficult indications in middle ear surgery. Further, it could be demonstrated that the PCT can be combined safely with titanium ossicular reconstruction prostheses. Regarding postoperative hearing results the negative preselection of pathological conditions has to be considered.

Adolescent↗
PubMed2001

Long term clinical outcome of a randomised controlled trial of anterior chamber lenses after high volume intracapsular cataract surgery.

BACKGROUND: Age related cataract remains the major cause of blindness throughout the world. In many countries, the majority of cataract surgery continues to be done by the intracapsular cataract extraction (ICCE) method. The results of a large randomised controlled trial of multiflex open loop anterior chamber intraocular lenses (ACIOL) were reported from a busy eye hospital in Nepal. METHODS: There was a randomised controlled trial of 2000 people with bilateral cataract reducing vision to less than 6/36. Interventions were ICCE with an ACIOL compared with ICCE with aphakic spectacles (+11 dioptres). Participants were followed at discharge, 6 weeks, 1 year, and 1 1/2-5 years after surgery. Visual acuity and clinical outcome were measured. A poor outcome was defined as vision <6/60. RESULTS: Visual outcome was comparable in the two groups. More of the control group experienced functional blindness due to loss of aphakic spectacles at 1 year. The majority of cases of poor outcome occurred in the first year after surgery. There was no indication of any lens related problems after 1 year. CONCLUSION: Multiflex open loop anterior chamber lenses are safe for up to 1 year of follow up when used by experienced surgeons, and the available evidence of 2-5 years of follow up suggests that the complication rate is reasonably low. An ACIOL at the time of cataract surgery offers benefits over routine ICCE surgery with aphakic spectacle correction as it avoids the problem of replacing lost and broken spectacles.

Adult↗
PubMed2001

A prospective study of 413 cases of lens-induced glaucoma in Nepal.

PURPOSE: To determine the frequency and types of lens-induced glaucoma (LIG), reasons for late presentation and outcome of current management. METHODS: Prospective case series of 413 patients/eyes with LIG over a 12-month period in 1998; 311 of these patients underwent cataract surgery. Visual acuity and intraocular pressure (IOP) were pre- and postoperatively assessed. RESULTS: Four hundred and thirteen (1.5%) of 27,073 senile cataracts seen in the outpatient department of Sagarmatha Choudhary Eye Hospital, Lahan, Nepal presented with LIG. There were 298 (72%) phacomorphic cases and 115 (28%) phacolytic glaucoma. Pain for more than 10 days was reported by 293 (71%) patients. The majority, 258 (62.4%), travelled a distance of more than 100 kms to the hospital. The major reasons for late presentation were "no escort" in 143 (34.6%) and "lack of money" in 128 (31.0%) cases. At presentation the IOP was more than 30 mm Hg in 327 (79%) eyes. Following cataract surgery, 251 (80.7%) had 21 mm Hg or less at discharge. The visual acuity was hand-movement or less before surgery in all eyes; at discharge 120 of 311 operated eyes (38.6%) achieved 6/60 or better, 97 (31.2%) less than 6/60, and 94 (30.2%) less than 3/60. The main causes for poor outcome in 94 cases were optic atrophy in 32 (34%) eyes, uveitis in 25 (26.6%)eyes and corneal oedema in 24 (25.5%) eyes. CONCLUSION: The results highlight the importance of early diagnosis and treatment of visually disabling cataract. There is a need to educate both the patient and the cataract surgeon of the dangers of lens-induced glaucoma and of the poor outcome if treatment is delayed.

Adult↗
PubMed2001

Postoperative astigmatism after intracapsular cataract surgery: results of a randomised controlled trial in Nepal.

PURPOSE: Postoperative astigmatism following intracapsular cataract extraction with or without anterior chamber intraocular lens implantation is reported as an outcome from a randomised controlled trial. METHODS: Five hundred and two of 1002 eyes randomised to intracapsular cataract extraction with anterior chamber intraocular lens (ICCE/AC IOL) and 417 of 998 eyes to intracapsular cataract extraction with aphakic spectacles (ICCE/AS) were seen for objective refraction one year after surgery. The prevalence and axis of astigmatism were evaluated using univariate analysis. Logistic regression was used to compare the postoperative astigmatism between the groups. RESULTS: Acceptable astigmatism (-0.5 to 0.0 DCyl) in the AC IOL group was found in 60 (12.0%) patients (95% CI 9.1%-14.9%) and in the aphakic spectacles group (AS) in 69 (16.5%) patients (95% CI 12.9%-20.1%), moderate astigmatism (-1.0 to-1.5 DCyl) was found in 153 (30.4%) patients (95% CI 26.4-34.6%) in ACIOL group and in 288 (69.1%) patients (95% CI 64.6%-73.6%) in AS group; and large astigmatism (-2.0 to - 8.0 D Cyl) was found in 289 (57.6%) patients (95% CI 53.1%-61.6%) in ACIOL group and in 60 (14.4%) patients (95% CI 11.0% 17.8%) in AS group. Large astigmatism was approximately four times more common in the ICCE/AC IOL group compared to ICCE/AS group. In both groups, most patients had "against-the-rule" astigmatism, 446 (88.8%) (95%CI 86.0%-91.6%) in AC IOL group and 348 (83.5%) (95%CI 79.9%-87.1%) in AS group. CONCLUSION: Astigmatism is common after intracapsular cataract extraction. Insertion of an anterior chamber IOL increases the risk of astigmatism.

Adolescent↗
PubMed1998

[Value of anterior chamber lenses in developing countries. Results of a clinical study].

UNLABELLED: There are estimated to be 20 million people blinded by cataracts, 80-90% of whom live in rural areas of developing countries where expert surgical resources are scarce. The majority of all cataract operations are still intracapsular extractions (ICCE). Aphakic correction using spectacles is problematical in developing countries. This study was undertaken to evaluate the safety of multiflex open loop anterior chamber intraocular lenses (AC IOLs). METHODS: A total of 2000 people attending Lahan Eye Hospital, South-east Nepal, with bilateral cataract were randomly allocated to receive in their first eye either ICCE with AC IOL (AC IOL group) or ICCE with aphakic correction (control group). All operations were performed by two ophthalmologists using a standardized technology and 4.5 x operating loupe magnification. Functional and best corrected vision was recorded. The primary outcome measure was poor vision after surgery, which was defined as a visual acuity of less than 6/60 at 1 year follow-up (WHO definition for severe visual impairment and blindness). FINDINGS: The median time needed to perform ICCE was 4.1 min and to perform ICCE with AC IOL 6 min. Of all study patients 91% were examined after 1 year. Five percent of the AC IOL group and 5.4% of the control group had a functional visual acuity of less than 6/60. Causes of reduced vision in the AC IOL group versus the control group were: correctable refractive error (22 vs 29), uveitis/secondary glaucoma (13 vs 2), endophthalmitis (4 vs 7), pre-existing eye diseases (4 vs 5), retinal detachment (0 vs 4), and corneal decompensation (0 vs 1). Of the control group, 24 patients were found to be functionally blind in the operated eye (vision < 3/60) because they did not wear their aphakic spectacles. Normal vision (WHO definition: > or = 6/18) was achieved best corrected in 89.9% of the AC IOL group and 93.2% of the control group. Analysis of additional long-term follow-ups (2-5 years post-operatively) has not yet been completed. INTERPRETATION: This study provides evidence that in developing countries well-manufactured multiflex open loop AC IOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction.

Anterior Chamber↗
PubMed1998

Posterior capsular plaque: a common feature of cataract surgery in the developing world.

PURPOSE: To study the histopathologic findings of posterior capsular plaque, a lesion that is discovered frequently in eyes undergoing cataract surgery in the developing world. METHODS: Two hundred human crystalline lenses removed from 200 eyes of 200 patients who underwent intracapsular cataract extraction at Sagarmatha Choudhary Eye Hospital in Nepal were analyzed histopathologically. RESULTS: Forty-nine lenses (24.5%) had a posterior capsular plaque. We confirm that the posterior plaques are composed of collagen that stains positively for Masson trichrome stain and that forms after pseudofibrous metaplasia of lens cells along the posterior capsule. The plaques form in a fashion analogous to a healing process. CONCLUSIONS: We postulate that posterior capsular plaques result from posterior migration of epithelium and pseudofibrous metaplasia of lens epithelium. Most of the posterior capsular plaques are minute and not likely to affect vision. However, a small percentage of plaques are thicker and are likely to impair vision after extracapsular cataract surgery.

Adult↗
PubMed1998

Prevalence of rhinosporidiosis of the eye and its adnexa in Nepal.

This study describes the clinical features, diagnosis, and treatment of rhinosporidiosis of the eye and its adnexa in a series of 76 cases in Nepal and six originating in India. The disease caused by the fungus Rhinosporidium seeberi was seen most frequently in young children between eight and 10 years of age. Males were infected more than females (2.5:1). The conjunctiva was the most common site of infection in 76 (92.68%) of the cases. The lacrimal sac was affected only in six (7.32%) cases. Simple total excision of the conjunctival polyps gave highly satisfactory results in cases of conjunctival sac infections. Except for one patient, there were no recurrences in the 76 cases. Meticulous excision of polyps provided a satisfactory result in the treatment of six cases with lacrimal sac infection. Recurrence was noted in one of these six cases followed up to two and a half years after surgery. The conditions diagnosed clinically were confirmed by histopathology. This review of 82 cases is the first such report of rhinosporidiosis from Nepal.

Adolescent↗
PubMed1997

Randomised controlled trial of anterior-chamber intraocular lenses.

BACKGROUND: There are an estimated 16 million people blind in both eyes with cataracts. Most live in rural areas of developing countries where surgical resources are scarce. There is no consensus on the most appropriate type of intraocular lens in situations where high-volume low-cost surgery is required. This study was undertaken to evaluate the safety of multiflex open-loop anterior-chamber lenses (ACIOLs). METHODS: 2000 people attending Lahan Eye Hospital, southern Nepal, with bilateral cataracts reducing vision to 6/36 or less were randomly allocated to receive standard surgery--intracapsular extraction (ICCE) with aphakic correction--or ICCE with an ACIOL in their first operated eye. The primary outcome was a visual acuity of less than 6/60 in the operated eye at 1 year follow-up. Visual acuity was measured for 91% of the cohort at 1 year. The sample size was estimated to detect a doubling in poor visual outcome from an estimated rate of 4% in the standard surgery (control) group. FINDINGS: The median (range) time taken to do the surgery was 6.0 (3.0-17.2) min for the ACIOL group and 4.1 (2.4-10.3) min for the control group. 1 year after surgery, 5.0% of the ACIOL group and 5.4% of controls had functional vision less than 6/60 (OR 0.93 [0.60-1.43], p = 0.71). The causes of poor vision in the ACIOL and control groups were: correctable refractive error (22 and 29), uveitis/secondary glaucoma (13 and two), endophthalmitis (four and seven), pre-existing eye disease (four and five), retinal detachment (none and four), cystoid macular oedema (two and none), corneal ulcer (one and one), and corneal decompensation (none and one). INTERPRETATION: This study provides evidence that, in rural areas of developing countries, multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction. Further follow-up is planned.

Anterior Chamber↗
PubMed1996

S103L reactive chondroitin sulfate proteoglycan (aggrecan) mRNA expressed in developing chick brain and cartilage is encoded by a single gene.

A large chondroitin sulfate proteoglycan (CSPG) identified in embryonic chick brain, and synthesized exclusively by neurons in a developmentally expressed pattern that coincides with migration and establishment of neuronal nuclei, reacts with a monoclonal antibody (S103L) developed against the cartilage-specific CSPG, aggrecan. The relationship of the brain and cartilage S103L CSPGs was established by chemical, biosynthetic and molecular analyses. Significant posttranslational differences (absence of keratan sulfate (KS), less CS, and different sulfation patterns) distinguish the brain S103L species from the cartilage S103L species. However, quantitative and qualitative Northern analysis, cassette RT-PCR and direct cloning and sequencing of the entire brain-specific S103L CSPG coding sequence, all indicate that the brain and cartilage core proteins are identical. Thus, although the S103L CSPG synthesized by chick brain and cartilage are the product of a single gene, they are clearly biochemically distinct and differentially expressed proteoglycan products, suggesting tissue specific roles for these proteoglycan homologs.

Aggrecans↗
PubMed1995

The biochemically and immunologically distinct CSPG of notochord is a product of the aggrecan gene.

Using the monoclonal antibody S103L, which reacts specifically with an epitope in the chondroitin sulfate-rich domain of the chick cartilage chondroitin sulfate proteoglycan (CSPG) core protein, we have identified the predominant CSPG expressed by notochord. This large notochord CSPG is first detected immunohistochemically as early as stage 16, long before chondrogenesis occurs, and is expressed continuously during the time of active neural crest migration and through the onset of sclerotomal differentiation. Because of the cross-reactivity of both notochord and cartilage CSPGs with the S103L antibody, extensive molecular and biochemical analysis of the two CSPGs was carried out. Striking differences distinguish the notochord and cartilage (aggrecan) CSPGs at the level of posttranslational modification. Notably, cartilage aggrecan carries a significant content of keratan sulfate (KS) chains, while the notochord CSPG is devoid of KS. In contrast, cartilage aggrecan lacks the HNK-1 epitope, while the notochord CSPG has a high content of HNK-1. Three different approaches were used to establish the relationship of the two CSPGs at the molecular level. Northern blot analysis, using aggrecan probes, detected same-sized messages from notochord and cartilage RNA. Overlapping fragments, generated by RT-PCR using primers covering 98% of the entire coding sequence from the known cartilage structure, were of identical size in notochord and cartilage. Taking advantage of our recent studies, which demonstrated a single base change in the aggrecan gene resulting in conversion of Glu to a STOP codon in exon 12 of chick aggrecan as the molecular basis of the defect nanomelia, we demonstrated that the same mutation was present in notochord mRNA from nanomelic chicks. These results provide evidence that the chick aggrecan gene is expressed very early in development in notochord and confirm that the core proteins expressed in chick notochord and cartilage are derived from the same gene. These findings strongly support the hypothesis that the final structural characteristics of each proteoglycan are determined not only by the core protein but also by tissue-specific, developmentally regulated posttranslational mechanisms, functioning within the context of the requirement for specific extracellular matrices.

Aggrecans↗