Different types of visual cells in the photoreceptor layer of the retinae of the treeshrew (Tupaia belangeri chinensis) as revealed by scanning microscopy.

BACKGROUND: The retinae of treeshrew have never been evaluated by scanning electron microscopic studies. MATERIALS AND METHODS: This work described the visual cells in the photoreceptor layer of the retinae of treeshrew (Tupaia belangeri chinensis) living on the high plateau of Yunnan, China, via scanning electron microscopy. RESULTS: Results indicated five morphologically different types of cones, two of which contain oil droplets in their inner segments. To our knowledge, no prior studies have reported oil droplets in the visual cells of higher mammals, only in lower vertebrate and primitive mammals. In addition, this study revealed one type of degenerative visual cell without outer segments. CONCLUSIONS: The findings signal the needs for additional studies to understand the physiological functions and phylogenetic relationships of the diversity of visual cells in this group of mammal.

Evaluation of in-house and commercial genotyping assays for molecular typing of hepatitis C virus in Hong Kong.

This study aims to evaluate genotyping assays for hepatitis C virus (HCV). An in-house nucleic acid sequencing method is performed in parallel with the Roche Linear Array HCV genotyping test on 73 HCV-positive (66 clinical samples and seven proficiency testing quality control samples) and 12 HCV-negative samples (11 clinical samples and one proficiency testing sample). The performance of the in-house method was comparable with that of the Roche assay (concordance rate: 89.4%). Discordant results included four mixed infections missed by the in-house method, two false-negatives with the Roche assay, and three discrepant results. The in-house method exhibited a higher resolution (subtype vs. genotype level) at a lower running cost (25% of the commercial assay). The in-house method was also used to genotype 375 HCV clinical isolates to determine the genotypic distribution of HCV in Hong Kong between 2005 and 2008. A total of 441 (52.8%) clinical isolates proved to be genotype 1, which shows a poorer response to interferon therapy. Genotype 6 was the next most common (32.0%). Prevalence of genotypes 2 and 3 was 7.7% and 6.6%, respectively, and prevalence of genotypes 4 and 5 was 0.9% and 0%, respectively. Although the in-house nucleic acid sequencing method failed to detect a few cases of mixed HCV infection, its high resolution and low running cost make it suitable for surveillance and outbreak investigation.

The relationship between mediastinal lymph node attenuation with parenchymal lung parameters in silicosis.

OBJECTIVE: Attenuation changes on computed tomography (CT) in mediastinal lymph nodes (LN) may be related to lung alterations and functional impairment in silicosis. DESIGN: CT and clinical data of 41 (64.2 +/- 8.3 years) males with silicosis were retrieved. Attenuation type (calcified, hyperdense, normodense) and calcification pattern (central, eccentric, dense, eggshell, speckled) of mediastinal LN were evaluated; LN attenuation of uncalcified LNs quantified on CT in six LN stations. Nodular profusion (CT-NP) and progressive massive fibrosis (CT-PMF) were graded. Relationships between LN, CT, lung function and clinical parameters were determined. RESULTS: LN sites were paratracheal (n = 39), subcarinal (n = 39), tracheobronchial (n = 37), aortopulmonary (n = 37), hilar (n = 27), and peri-oesophageal (n = 21). LNs were calcified, hyperdense and normodense in 107, 85 and 54 LN stations, respectively. Uniformly calcified LN was most common, followed by speckled calcification. Central, eccentric and eggshell calcification was rare. CT-NP scores > or = 16 were associated with higher LN attenuation and number of calcified LN stations than CT-NP scores < 16. PMF had no influence over LN morphology or calcification pattern. LN attenuation correlated with CT-PMF (r = 0.36, P = 0.01), CT-NP (r = 0.54, P < 0.001) and DLCO/VA (r = -0.33, P = 0.02). CONCLUSION: Uniformly calcified and hyperdense LNs are common in silicosis, and eggshell LN calcification is rare. There are associations between LN attenuation and lung function impairment, and CT grades of nodular profusion and PMF.

Identification of differentially expressed genes from ovarian cancer cells by MICROMAX cDNA microarray system.

Using the MICROMAX cDNA microarray system, we were able to identify genes that are differentially overexpressed in ovarian cancer. A total of 30 putative genes, which are differentially overexpressed in ovarian cancer cell lines, were identified. The differential expression of some of these genes was further confirmed by real-time RT-PCR. Using this strategy, we have identified genes that either overexpress in all cancer cell lines or in only some cancer cell lines. Further characterization of these genes will allow them to be exploited in diagnosis, prognosis, anticancer therapy, and molecular classification of ovarian cancer.

Postnatal changes of vascular endothelial growth factor (VEGF) expression in the retinae of normal and hypertensive rats.

Vascular endothelial growth factor (VEGF) has been shown to have potent mitotic activity specific to vascular endothelial cells and has been related to vascular permeability, angiogenesis and cell proliferation in both normal and pathological situations. The present study aimed at elucidating the spatio-temporal changes in the postnatal expression pattern of VEGF in the retinae of both normal and hypertensive rats. In situ hybridization with a riboprobe showed that in the pre-hypertensive stage (2 weeks postnatal, prior to the increase of the blood pressure of the hypertensive rat), VEGF expressed strongly in the retinal pigment epithelium (RPE) and inner nuclear layer (INL) but weakly in the ganglion cell layer and nerve fiber layer in both the normal and hypertensive rats. During the early hypertensive stage (6 weeks postnatal, initial increase of the blood pressure of the hypertensive rat), similar expression pattern was maintained but the INL of the hypertensive rat was found to have more positive cells in clusters than that of the normal rat. When a sustained high blood pressure was developed (12 weeks postnatal, sustained hypertensive stage) in the hypertensive rat, the VEGF expression was much reduced in all layers of the retina although weak expression was still observed in the RPE of the normal rat and RPE and INL of the hypertensive rat. Western blot analysis however showed that VEGF protein expression in the retina was much stronger in the hypertensive rat than in the normal rat at 2 and 6 weeks postnatal. At 12 weeks, the VEGF protein returned to a level comparable to that found in the normal rat. It is speculated that the change of the VEGF protein expression pattern during the early phase of the development of hypertension may be related to the subsequent changes in the retinal vasculature of the hypertensive rat.

Noninvasive cardiac evaluation of patients receiving adriamycin-containing adjuvant chemotherapy (FAC) for stage II or III breast cancer.

Cardiac function was evaluated by noninvasive methods in 55 patients with stage II or III breast cancer treated with adjuvant Adriamycin containing combination chemotherapy (FAC). None of the 44 patients who remained free of disease for a median follow-up period of 36 months, or those who were retreated with Adriamycin up to a median cumulative total dose of 450 mg/m2 (nine patients), developed clinical evidence of cardiac decompensation. The median electrocardiographic QRS voltage and ejection fraction decreased by 11% and 5%, respectively, in the former and by 21% and 10% in the latter group at the conclusion of chemotherapy. These parameters tended to return to the baseline at the time of the last visit. The decreases in QRS voltage and ejection fraction were greater in patients who received radiotherapy and had prior cardiovascular disease than in those without such risks. The remaining two patients were retreated with higher total doses of Adriamycin. Both showed clinical evidence of cardiac decompensation and gradual deterioration of the noninvasively measured parameters of cardiac function. One patient was alive six months after the discontinuation of Adriamycin at a total dose of 842 mg/m2, and the other died of pulmonary embolism two months after receiving a total of 892 mg/m2. Our study shows that Adriamycin can be included in adjuvant therapy without inducing clinically significant alterations in cardiac function; however, patients who have additional risk factors should be monitored closely with noninvasive studies while they receive this drug.

Systemic d-phenylalanine and d-leucine for effective treatment of pain in the horse.

This study showed that subcutaneous injection of a solution of D-amino acids produced effective analgesia in horses. It is postulated that systemic D-phenylalanine and D-leucine may become one of the safe, effective and nonaddictive drugs for acute and chronic pain treatment. These D-amino acids cause analgesia by presumably preserving brain endorphins. They may bind reversibly to enkephalinases and prevent enzymatic degradation of enkephalins.

Monoaminergic mechanism of electroacupuncture analgesia.

We studied the effects of systemic injections of monoamine depletors, enhancers or receptor blockers on electroacupuncture analgesia (EAA) in mice. The following results emerged. (i) EAA is reduced by depletors of monoamines (tetrabenazine, TBZ depletes all monoamines; para-chlorophenylalanine, PCPA depletes serotonin; alpha-methyl-para-tyrosine, AMPT depletes catecholamines). However, depletion of noradrenaline and increase of serotonin by disulfiram enhances EAA. (ii) Replacement of depleted monoamines after TBZ treatment by their precursors (5-HTP or L-DOPA) restores EAA. (iii) EAA is enhanced by potentiating serotonin and dopamine by probenecid. EAA is also enhanced by the administration of monoamine precursors (L-DOPA for dopamine, 5-HTP for serotonin). The dopamine receptor stimulator, apomorphine, reduces EAA. (iv) EAA is also reduced by receptor blockade of catecholamines (by haloperidol), or blockade of noradrenaline (by yohimbine) or serotonin (by cinanserin). However, blockade of dopamine by pimozide has no significant effect on EAA. There are two main conclusions: (i) EAA results are similar to those previously reported for SPA for all drugs except apomorphine and pimozide; and (ii) EAA shows consistent results only with manipulations of serotonin: the data indicating that EAA (at 200 Hz) is mediated by serotonin. Since previous studies show that raphe or DLF (dorsolateral fasciculus) lesions abolish EAA, we postulate that descending axons from raphe release serotonin to inhibit trigeminal or spinal cord nociception during EAA.

Electroacupuncture treatment of morphine-dependent mice reduces signs of withdrawal, without showing cross-tolerance.

Morphine pellets (75 mg morphine base per pellet) were implanted subcutaneously in mice (B6AF1/J) and were surgically removed after 3 or 8 days. During morphine abstinence (7 h after pellet removal), the mice were treated with electroacupuncture (EA). The results indicate that EA analgesia shows no cross-tolerance to morphine. Additionally, EA reduced withdrawal behaviour (jumping) in 50% of the mice during morphine abstinence.