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Biomedical subjects

D M Albert

Publications and source records attributed to D M Albert.

At least 145 records · Page 8Linked to original sources
PubMed1990

Relative survival rates after alternative therapies for uveal melanoma.

Survival in a group of 556 patients with uveal melanoma treated by proton beam irradiation with a median follow-up of 5.3 years was compared with that of 238 patients enucleated during the same 10-year period as irradiated patients (July 1975 to December 1984) with a median follow-up of 8.8 years, and 257 patients enucleated during the preceding 10 years (January 1965 to June 1975) with a median follow-up of 17.0 years. Adjustments were made for known prognostic factors including age, tumor location, tumor height, and clinical estimate of tumor diameter (for enucleated patients this was estimated in a regression equation relating histologic to clinical measurement). The overall rate ratio for all cause mortality was 1.2 (95% confidence interval, 0.9-1.6) for the concurrent enucleation series versus proton beam, and 1.6 (95% confidence interval, 1.2-2.1) for the earlier enucleation series versus proton beam. Relative rates of metastatic death, cancer death, and all cause mortality comparing alternative treatments were found to vary with time after treatment. Interval-specific rate ratios were evaluated using proportional hazards models fitted to separate time intervals after treatment. For all three outcomes, rate ratios were over two and statistically significant for the first 2 years after treatment and closer to one and nonsignificant after year 6 comparing the two enucleation groups with proton beam. Results suggest that treatment choice has little overall influence on survival in patients with uveal melanoma.

Adult↗
PubMed1990

Histopathologic verification of Verhoeff's 1918 irradiation cure of retinoblastoma.

The authors studied an eye obtained postmortem from the first patient with a successfully irradiated retinoblastoma. This patient, first treated by Verhoeff in 1917, had been followed for 71 years. Ophthalmoscopy disclosed a depressed chorioretinal scar, approximately 3 disc diameters (DD) in size, with baring of the sclera temporal to the macula. This case is historically significant, in that Verhoeff and Reese debated as to whether this tumor regressed spontaneously or secondary to irradiation. Results of histopathologic, immunohistochemical, and ultrastructural examination showed a chorioretinal, neuroglial scar without evidence of calcification, necrotic tumor cells, or residual retinoblastoma. The authors discuss the clinical and histopathologic findings in spontaneously regressed retinoblastoma, retinoma/retinocytoma, and irradiated retinoblastoma. They believe that Verhoeff was correct in his belief that x-ray therapy had cured this patient.

Aged↗
PubMed1990

Tracheal stenosis in infants and young children.

Eight cases of intra-thoracic tracheal stenosis presenting to the ENT department at the Hospital for Sick Children, Great Ormond Street, over the past 10 years are reported. The varied aetiology and presentation of these cases is discussed and the frequency of associated cardio-pulmonary anomalies emphasized. Difficulties in diagnosis and investigation are outlined, in addition to an overview of current management. While the overall outlook for many of these children remains poor there is reason to believe that a balance of conservative management and surgical reconstruction in selected cases will result in improved survival figures.

Child, Preschool↗
PubMed1990

[Sub-choroidal implanted Greene melanoma: an animal experiment model for malignant choroid melanoma].

A modified technique for subchoroidal transplantation of amelanotic Greene melanoma cells and the intraocular growth patterns of this tumor in rabbit eyes are described. Tumor fragments were implanted via a scleral tunnel in 71 rabbit eyes, with 64 successful tumor growths, producing a prominent, circumscribed choroidal mass within 12-14 days of surgery. Choroidal Greene melanoma in rabbits resembles human epithelioid uveal melanoma in both its growth patterns and morphologic characteristics. The authors' implantation technique guarantees reliable growth of choroidal tumors with easily reproducible size and location. The experimental choroidal melanoma model is particularly valuable in clinical studies where a large number of tumors, with limited variation, is necessary for different experimental groups.

Animals↗
PubMed1990

Functional assessment of the paediatric laryngeal airway.

After resolution of conditions necessitating tracheostomy in children, decannulation may be extremely difficult and associated with significant morbidity. Endoscopy and radiography can identify anatomical abnormalities preventing decannulation. Physiological abnormalities are, however, more difficult to assess. A system has been developed whereby functional upper airway resistance can be calculated in children with a tracheostomy. The instrument used was a modified Mercury Electronics rhinomanometer. A probe was placed through the tracheostome and another probe was situated in an occluding anaesthetic face mask. Upper airway resistance was derived from the differential pressure and flow changes recorded in anaesthetized children who were breathing spontaneously. Studies in 26 children have revealed low airway resistance in all those successfully decannulated. Further studies will hopefully allow identification in advance of children who will have decannulation difficulties.

Adolescent↗
PubMed1990

Effect of laryngeal stenting in a rabbit model.

A short length of oversize endotracheal tube was sutured in the undamaged subglottis of 22 rabbits to explore the effect of laryngeal stents. The stent was secured to lie beneath the vocal cords. The histologic changes were minimal irrespective of the type of tube used and how long it remained in situ. These findings are consistent with the theory that tube movement is necessary to produce stenosis and are encouraging given the widespread use of stents in pediatric laryngeal reconstruction. The role of gastric acid in producing subglottic stenosis is discussed.

Animals↗
PubMed1990

The otologic significance of cleft palate in a Sri Lankan population.

The otologic findings from 197 subjects with repaired and unrepaired clefts and 121 noncleft controls are presented. All data were collected in Sri Lanka during a 3-week period attached to the Sri Lanka Project in 1986. Subjects were examined otoscopically and also tested audiometrically if they were able to perform a pure-tone audiogram, a performance test, or a distraction test. Subjects with clefts of the palate were found to have fewer otoscopically normal ears than the controls. A comparison between subjects with unrepaired and repaired palates revealed a similar rate of otoscopically normal ears in subjects older than 10 years of age. Comparisons for younger ages could not be performed because of a lack of subjects less than 10 years of age who had repaired palates. The impedance data were used to verify the accuracy of otoscopy in detecting effusion.

Acoustic Impedance Tests↗
PubMed1990

S100 immunophenotypes of uveal melanomas.

To determine whether ocular melanomas are immunophenotypically identical to cutaneous melanomas, 34 primary and metastatic choroidal melanomas representing all major histotypes defined by the Callender's classification, plus one melanoma of the iris and one conjunctival melanoma, were subjected to a panel of immunostains designed to distinguish anaplastic biopsies of cutaneous melanomas from carcinomas and lymphomas. All ocular melanomas were found to express the intermediate filament vimentin but not keratin, and all but 2 were melanotic by immunostaining. Thirty-three of 34 (97%) choroidal melanomas were strongly stained with a rabbit polyclonal antibody (P-S100) developed against the S100 protein family. In contrast, none of 14 spindle cell type primary lesions was stained with a monoclonal antibody (MAB-079) specific for both S100 alpha and S100 beta, the best-characterized S100 polypeptides. Furthermore, only 2 of 5 epithelioid and 3 of 10 mixed-cell-type melanomas were weakly reactive. Overall, 14.7% (5 of 29) were stained. In comparison, MAB079 stained 85% of all cutaneous melanomas. Five metastases of choroidal melanomas (spindle B, epithelioid, and mixed cell types) from different organ sites also were stained by P-S100 but not by MAB079. These findings were corroborated by immunostaining with another monoclonal antibody (MAB4D4) specific for S100 beta. Differential staining by the polyclonal but not the monoclonal antibodies suggests the possible presence of a variant S100 polypeptide(s) in choroidal melanomas. Since S100 alpha, S100 beta, and related proteins appear to be physiologically important, additional studies of these S100 proteins may shed light on the etiology or pathology of choroidal melanomas.

Antibodies, Monoclonal↗
PubMed1990

Immunofluorescent characteristics of the diabetic cornea.

In view of the increasing awareness of corneal abnormalities in diabetes, five diabetic and five nondiabetic post-mortem corneas were investigated. Indirect fluorescent antibody techniques were used for the detection of immunoglobulin, complement components, fibrinogen, and fibronectin, as some of these had already been found in the kidney, pancreas, and skin of diabetic patients. There was no obvious difference in the deposition of IgG, IgA, IgM, fibrinogen, or fibronectin between diabetic and control corneal specimens. Five diabetic specimens versus three control specimens demonstrated positive staining at 1:50 dilution for complement components Clq, C3, and C4. This staining was primarily present in the epithelium. Of greater interest was the finding that complement components were present in the basement membrane of two diabetic patients, but were not found in nondiabetic patients. In conclusion, diabetic corneas demonstrate unusual staining for complement components in the epithelial basement membrane.

Adult↗
PubMed1990

In vitro toxicity of gentamicin to corneal epithelial cells.

We report morphologic and viability changes in the rabbit corneal epithelium exposed in vitro to gentamicin sulfate. Rabbit corneal epithelial cells (3 x 10(5)) were seeded in replicate 24-well plates at their first in vitro passage, and gentamicin in concentrations of 0, 50, 250, 500, 1,000, or 5,000 micrograms/ml was added to the tissue culture medium beginning 7 days after subculture. By phase contrast microscopy, changes in cell morphologic appearance, particularly increased cytoplasmic granularity, were observed in the 5,000-micrograms/ml groups as early as 24 h after introduction of the drug. At 48 h, similar findings were observed in the 250-micrograms/ml group and at all higher concentrations. The cytoplasmic granularity was not noted in the 0- or 50-micrograms/ml groups. By electron microscopy, these observations correlated with ultrastructural findings of increased accumulations of intralysosomal bodies beginning in the 250-micrograms/ml group after 48 h of exposure to gentamicin. Furthermore, a statistically significant difference (p = 0.001) was demonstrated between the total number of viable cells in the low-dose group (50-micrograms/ml) and the high-dose groups (greater than or equal to 250-micrograms/ml) for exposure periods of 48 h or more. These findings demonstrate aminoglycoside toxicity to corneal epithelial cells in vitro similar to that seen in the human kidney and conjunctiva.

Animals↗
PubMed1989

Identification and significance of multinucleate tumor cells in retinoblastoma.

Multinucleate tumor cells were observed in a case of a retinal tumor suspected to be a retinoma (retinocytoma). On electron microscopy, these cells had characteristics of retinoblastoma. Similar cells were observed in an irradiated model of retinoblastoma grown in a nude mouse. We suggest that the presence of these cells indicates differentiation and/or regression of the tumor.

Animals↗
PubMed1989

A perfusion system developed for 31P NMR study of melanoma cells at tissue-like density.

A perfusion culture system has been developed for 31P NMR study of human uveal melanoma metabolism by adapting the Vitafiber I cartridge system (Amicon). 31P NMR spectra collected weekly during periods of up to 10 weeks demonstrated increasing levels of phosphorus metabolites as the anchorage-dependent cells grew to tissue-like density.

Equipment Design↗
PubMed1989

Malignant transformation of an iris melanocytoma. A case report.

A 34-year-old Caucasian woman was diagnosed as having a pigmented iris tumor showing recent growth and satellite lesions. The tumor was associated with pigmentation of the anterior chamber angle and secondary unilateral glaucoma. After local excision, histopathologic studies revealed the plump polyhedral cells typical of melanocytoma. However, the examination of additional sections showed evidence of malignancy. The diagnosis of a melanocytoma that transformed into malignant melanoma was made and later confirmed by electron microscopic studies. Following surgical excision of the tumor, the eye maintained normal intraocular pressure. There was no evidence of recurrence 4 years after surgery.

Adult↗
PubMed1989

The use of alcohol-stored cartilage in experimental laryngotracheal reconstruction.

Alcohol-stored homograft ear cartilage was used to reconstruct the larynx in an animal model. When sacrificed after one month the cartilage was incorporated in a stable position with mucosa on the luminal surface. Some resorption of implanted cartilage occurred, particularly where surgical trauma or sutures allowed granulation tissue to penetrate into the matrix. This paper emphasises the role that cartilage damage plays in resorption and strives to improve results in laryngotracheal reconstruction by highlighting the situations in which graft damage can be significant.

Absorption↗
PubMed1989

Johan Lorenz Odhelius and cataract extraction in Sweden.

In 1775, Johan Lorenz Odhelius presented a lecture to the Royal Academy of Science at Stockholm describing his preferred operation for cataract. Odhelius generally endorsed the technique described by Daviel (1753) 22 years earlier, but included additional observations and modifications based on his own experience. This address was published in Swedish (Odhelius 1775) in the same year and is one of the earliest ophthalmological monographs by a Swedish author. Odhelius' publication is now translated into English and put into its historical perspective.

Cataract Extraction↗
PubMed1989

Congenital corneal keloid.

The clinical course and pathological findings in an infant with a congenital corneal opacity, aniridia, and cataract of the right eye and anophthalmia of the left orbit are reviewed. Although the lesion was thought to represent a dermoid pre-operatively, the keratoplasty specimen revealed disorganized and vascularized connective tissue, with thickened, keratinized epithelium. Bowman's and Descemet's membranes as well as the endothelium were absent. These histopathologic findings were felt to represent a congenital corneal keloid. The co-existence of aniridia in the involved eye and anophthalmia of the contralateral socket are hypothesized to be evidence that a primary ocular developmental disorder, rather than a reparative process, resulted in the corneal alteration. The difficulties of penetrating keratoplasty in lesions of this sort are examined.

Corneal Opacity↗