Ultrastructure and 3D transmission electron tomography of collagen fibrils and proteoglycans of swollen human corneal stroma.

BACKGROUND: The transparency of the cornea is regulated by the unique organization of collagen fibrils (CFs) which is maintained by proteoglycans (PGs). The interlacing of CF lamellae in the anterior stroma provides the biomechanical properties of the cornea. OBJECTIVE: To investigate the alterations of CFs and PGs in the swollen cornea, with special reference to the anterior stroma by using electron microscopy and 3D ultrastructural tomography. METHOD: Nine healthy normal scleral corneal rings (age from 40 to 65 years) were hydrated individually in deionised water to induce swelling in the cornea. Three of them were hydrated for 2hr whereas the other three were hydrated for 48hr. The remaining three scleral normal corneal rings were used as a control.The corneas were processed for electron microscopy (EM) to study the CFs and PGs. Ultrathin sections were observed using transmission electron microscopy (JOEL 1400) and digital images of CFs, PGs and lamellae were captured using a bottom mounted Quemesa camera and iTEM Soft Imaging System. The software program 'Composer-x64, version 3.4.2.0' was used to construct individual 3D images from 120 digital images taken from -60 to + 60 degree angles. RESULTS: The 3D tomography showed the degeneration of microfibrils within the CFs of the swollen cornea. The CF diameter was significantly reduced and the interfibrillar spacing significantly increased in both the 2hr and 48hr hydrated corneas compared to the normal cornea. Within the hydrated corneas, the CF diameter was smaller and the interfibrillar spacing was increased in the middle and posterior stroma compared to the anterior stroma. The PG area in both the 2hr and the 48hr hydrated cornea was reduced in the anterior stroma, whereas it was increased in middle and posterior stroma compared to the normal cornea. The density of the PGs in both the 2hr and the 48hr samples, was reduced compared to the density of PGs in the normal cornea. CONCLUSION: The CFs, PGs and lamellae had degenerated, caused by swelling. 3D imaging demonstrated that the impairment of the microfibrils and PGs within the CF, is caused by the excessive hydration or swelling in the anterior as well as in the middle and posterior stroma. The lamellae of the anterior stroma which provides the biomechanical strength in the normal cornea, had degenerated in the swollen corneas due to the presence of the damaged CFs and PGs.

Tea tree oil: in vitro efficacy in otitis externa.

OBJECTIVE: The purpose of this study was to determine the susceptibility of organisms causing otitis externa (OE) to the essential oil of Melaleuca alternifolia, or tea tree oil (TTO). METHODS: Fifty-seven swabs were taken from the ears of 52 patients with OE for culture and sensitivity. A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of TTO for each organism. RESULTS: In 51 percent of the swabs taken, pathogenic organisms were cultured. Of these cultures 71 percent, both bacteria and yeast, were susceptible to TTO 2 percent or less. The only organism showing resistance to TTO was Pseudomonas aeruginosa; however 25 percent of these bacteria were sensitive. CONCLUSION: Tea tree oil may have a role to play in the treatment of OE. However, more work needs to be done to enhance the anti-pseudomonal effect and to assess ototoxicity.

Cerebral aneurysm associated with an intracranial tumour: staged endovascular and surgical treatment in two cases.

Two cases are reported in which an anterior communicating artery aneurysm was associated with an intracranial tumour. The tumour was a suprasellar meningioma in one case and an optic chiasm/hypothalamic astrocytoma in the other. In both cases, the aneurysm was successfully embolized using Guglielmi detachable coils. Subsequently craniotomy was performed with complete excision of the meningioma and subtotal removal of the astrocytoma. Endovascular techniques can be employed to make the surgical excision of an intracranial tumour co-existing with an incidental aneurysm safer.

Age at menarche and nutritional supplementation.

Retrospective data on age at menarche were collected for 832 Guatemalans 15-30 y in age to test whether exposure to a high energy and high protein supplement (Atole: 163 kcals/682 kJ and 11.5 g protein per cup or 180 mL) during childhood led to earlier menarche than did exposure to a low energy, no protein supplement (Fresco: 59 kcals/247 kJ in 180 mL). Mean age at menarche was similar in Atole (13.75 +/- 1.22 y; mean +/- SD) and Fresco (13.74 +/- 1.36 y) groups. The corresponding value for immigrants (n = 144), subjects not exposed to the supplements, was 13.55 +/- 1.20 y. Year of birth as well as socioeconomic status (SES) were associated with age at menarche. Age at menarche declined by 0.69 y over the 15-y period and menarche occurred earlier in higher SES households. Significant positive interactions between supplement type and SES and between supplement type and year of birth were found, but plausible explanations for them could not be advanced.

Effects of age misstatement on the utility of age-dependent anthropometric indicators of nutritional status in rural Bangladesh.

We report the effects of age error on use of weight-for-age and height-for-age for assessing and screening malnutrition, and for identifying factors of malnutrition in 679 children aged 22-59 months in Companiganj, in rural Bangladesh. Overreporting and random error in age and correlation of age error with each of the anthropometric indices are observed. As a result, the proportion of children having less than or equal to 60 per cent of median weight-for-age is overestimated by five percentage points and the proportion having less than 80 per cent of median height-for-age is overestimated by six points. Loss in sensitivity (proportion of malnourished children correctly identified) for the above cutoff points is 20 per cent for weight-for-age and 28 per cent for height-for-age, compared to the situation in the absence of age error. Although mother's education is not a significant determinant of weight-for-age and height-for-age, age error makes mother's education appear artifactually significant in the analysis of variance.