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Biomedical subjects

K McClellan

Publications and source records attributed to K McClellan.

10 recordsLinked to original sources

Suppurative keratitis in rural Bangladesh: the value of gram stain in planning management.

External eye disease which result in corneal scarring are an important cause of blindness in Bangladesh and at the Chittagong Eye Infirmary and Training Complex (EITC) over 200 cases of suppurative keratitis are managed each year. We reviewed the records of 127 cases of microbial keratitis to determine the relative contributions of Gram stain and culture to diagnosis of the causative organism. There were 107 culture-proven cases of microbial keratitis amongst the 127 patients in this study. Gram stain was positive in 89 cases which represents 70% of the total and 83% of all culture-proven cases. Streptococcus pneumoniae and Pseudomonas sp were the commonest bacteria isolated and Aspergillus sp and Fusarium sp the commonest fungi. In 20 cases (16%) no organism was isolated on Gram stain or culture. Our results support the use of both Gram stain and culture in isolation of the causative organism in cases of suppurative keratitis in Bangladesh. However the low cost of Gram stain and its useful recovery rates for both bacteria and fungi support its use as an initial investigation for microbial keratitis at the secondary level of eye care in rural Bangladesh.

Anti-Bacterial Agents

Endophthalmitis following cataract extraction.

We describe a case of bacterial endophthalmitis complicating routine cataract extraction and intraocular lens implantation in a 91-year-old woman. The ocular and systemic factors that may have predisposed to intraocular infection in this case, and the possibility of predicting these pre-operatively, are discussed.

Adenocarcinoma

Acanthamoebic keratitis diagnosed by paracentesis and biopsy and treated with propamidine.

A previously healthy 53-year-old man had keratitis of the right eye for six months, unresponsive to topical medical therapy. Acanthamoeba was grown from tissue obtained by corneal biopsy and from aqueous from an anterior chamber tap. The patient was treated with propamidine isethionate 0.1% drops and dibromopropamidine isethionate 0.15% ointment, and after two and a half months the ocular inflammation was continuing to resolve. This case supports a role for the diamidines in the treatment of acanthamoebic keratitis.

Acanthamoeba

Microbiological diagnosis of suppurative keratitis in Bangladesh.

Experience in setting up an inexpensive microbiology laboratory in the Bangladesh National Society for the Blind Eye Hospital and Training Complex at Chittagong is presented, together with the results of a pilot study to identify organisms responsible in 33 consecutive cases of suppurative keratitis in the Chittagong area of Bangladesh. Of the 33 cases 21 were positively identified by means of Gram stain and/or culture. Two-thirds of the responsible organisms were bacteria, and one-third were fungi. The bacterial causes included Streptococcus pneumoniae and Pseudomonas aeruginosa. The fungi isolated were Aspergillus fumigatus, Aspergillus ochraceus, and Fusarium solani. Among the causes of failure to diagnose the organism was chronicity of infection and previous treatment. The value of the study in the planning of future treatment regimens, and the implications of setting up similar relatively cheap microbiology laboratory facilities in developing countries, are discussed.

Bacteria

Concurrent pineoblastoma and unilateral retinoblastoma: a forme fruste of trilateral retinoblastoma?

A 10-month-old boy who presented with strabismus and symptoms of intracranial hypertension was found to have a pineoblastoma and a unilateral ocular retinoblastoma. Despite enucleation of the eye, subtotal removal of the pineoblastoma, and craniospinal axis irradiation, the patient died 6 months later from disseminated intracranial neoplasm. As there was no clinical evidence of bilateral retinoblastoma, this case may represent a forme fruste of the trilateral retinoblastoma complex. The clinicopathological features of this unusual syndrome are reviewed.

Brain Neoplasms

Anemia of prematurity: determinants of the erythropoietin response.

This study was undertaken to determine the factors that are important in determining the erythropoietin response in low-birth-weight infants during the period of so-called anemia of prematurity. In the first weeks of life oxygen consumption in a group of 21 infants gradually increased as hemoglobin level fell. The magnitude of the erythropoietin response inversely varied with the central venous oxygen tension (P-vO2) (r = -0.55, P less than 0.001). When the P-vO2 declined to less than 30 torr, erythropoietin values were uniformly increased above the "normal" range (defined as the values associated with P-vO2 greater than 38 torr). Erythropoietin values varied inversely with hemoglobin but in general did not exceed the values observed for normal adult men. The erythropoietin values in the infants were remarkably lower at any given hemoglobin level when compared with those of older children with anemia resulting from bone marrow failure. In general, elevations of erythropoietin were seen when the hemoglobin concentration declined to less than 10.0 gm/dl. Change in heart rate did not appear to be a reliable indicator of the presence of anemia; rather, it correlated best with oxygen consumption.

Adult

Dextran 40-containing incubation media: effect on lens electrolyte and water balance.

The effect of dextran 40 on lens swelling and electrolyte balance in lenses stressed by incubation in Ca++-free media was studied. Dextran 40 substantially inhibited lens swelling, Na+ gain, and K+ loss caused by six-hour incubation in Ca++-free media. After an additional 12-hour incubation in Ca++-enriched media, the water and electrolyte balance in the dextran 40-incubated group was essentially the same as that of lenses that were never exposed to a Ca++-free media. Those lenses that were not incubated in dextran 40 demonstrated significant residual lens swelling and electrolyte imbalance. It is concluded that dextran 40, by virtue of its oncotic effect, inhibits colloidal osmotic swelling and exerts a protective effect on lens function under a stress situation.

Animals