After-cataract formation in newborn rabbits implanted with intraocular lenses

PURPOSE

Comparison of the after-cataract formation in newborn rabbits implanted with a heparin-surface-modified (HSM) intraocular lens (IOL), a silicone IOL, or no IOL.

METHODS

Two groups of 3-week-old rabbits were used. In Group 1 (n = 11), lensectomy was performed in both eyes. One eye was selected at random and an HSM IOL was implanted in the capsular bag; the other eye was left aphakic. In Group 2 (n = 13), lensectomy was performed in both eyes. An HSM IOL was implanted in one eye, a silicone IOL in the other. The wet mass of the dissected after-cataract was determined 3 months after surgery in both groups.

RESULTS

In Group 1, the wet mass of the dissected after-cataract was 17.0 +/- 6.5 mg (mean +/- SEM) in eyes implanted with an HSM IOL and 159.7 +/- 17.0 mg in aphakic eyes. This difference was statistically significant (P < .01). In Group 2, the wet mass of the dissected after-cataract was 18.3 +/- 4.3 mg in eyes implanted with an HSM IOL and 25.7 +/- 5.2 mg in eyes implanted with a silicone IOL. No statistically significant difference was found.

CONCLUSIONS

In young rabbits, implantation of an IOL in the capsular bag following lensectomy reduced cell proliferation.

Haemodynamic effects and pharmacokinetics of oral d- and l-nebivolol in hypertensive patients

OBJECTIVE

Nebivolol is a selective beta 1-adrenergic receptor blocker possessing an ancillary vasodilating effect. The objective of the present study was to study the haemodynamic and pharmacokinetic properties of nebivolol 5 mg once daily in a double-blind, placebo-controlled cross-over study.

METHODS

Fifteen patients, 12 men and 3 women, with essential hypertension were investigated. Blood pressure and peripheral circulation were determined after acute oral nebivolol administration, 5 mg daily, and after 4 weeks treatment.

RESULTS

The acute effect on blood pressure upon single-dosing was weak and non-significant. After 4 weeks both systolic blood pressure (152 vs 163 mmHg) and diastolic blood pressure (89 vs 97 mmHg) were significantly reduced after nebivolol treatment as compared to placebo. Following the first dose the venous volume was higher on placebo (5.88 ml.100 ml-1 tissue) as compared to active nebivolol treatment (5.17 ml.100 ml-1 tissue), while there were no statistically significant differences with regard to venous plethysmographic findings after 1 month on placebo (5.53 ml.100 ml-1 tissue) or on active treatment (5.97 ml.100 ml-1 tissue). Calculated peripheral resistance did not differ between active treatment (617 units) or placebo (548 units) after the first dose, whereas it was significantly lowered after 4 weeks of nebivolol treatment (483 units) as compared to placebo (593 units).

CONCLUSIONS

Oral nebivolol 5 mg once daily lowered blood pressure and heart rate during steady state compared to placebo. Moreover, venous volume was reduced during acute but not steady-state dosing, while peripheral resistance was unaffected in the acute phase but reduced during steady state. Plasma concentrations of the separate enantiomers plus hydroxylated metabolites after the first and last dose in hypertensive patients were similar to those in healthy subjects.

Evaluation of the effect on breast cancer mortality of population based mammography screening programmes

OBJECTIVE

To evaluate, by analysis of breast cancer mortality data from all the 26 Swedish counties for the years 1971 to 1990, whether the effect of the introduction of mammography screening in Sweden can be assessed by observation from existing mortality data.

METHODS

A Poisson regression model was used to study whether a decrease in breast cancer mortality among women aged 50-74 years was associated with the extent of mammography screening in different counties and periods.

RESULTS

In regions where mammography screening had been introduced, breast cancer mortality tended to be decreased, on average, compared with regions without screening. If a 10 year time lag between the start of screening and its full effect on mortality is assumed then the estimated reduction in breast cancer mortality associated with introduction of screening was 19% with a 95% confidence interval ranging from -3% to 37%.

CONCLUSIONS

The results suggest that the effect of mammography screening may be studied using existing routine mortality data and appropriate statistical modelling. This way of assessing the outcome of the screening is valuable when continuously monitoring a screening programme that has become a public health routine.

Comparison of the potencies of (+)- and (-)-2-ethylhexanoic acid in causing peroxisome proliferation and related biological effects in mouse liver

Male C57BL/6 mice were exposed to 1% (w/w) (+)- or (-)-2-ethylhexanoic acid or an equimolar mixture of these enantiomers in their diet for 4 or 10 days. A significant increase in liver weight and a 2- to 3-fold increase in the protein content of the mitochondrial fraction were seen in all cases. Peroxisomal palmitoyl-CoA oxidation was increased 2- to 3.5-fold after 4 days of treatment and 4- to 5-fold after 10 days, while the corresponding increases in peroxisomal lauroyl-CoA oxidase activity were 2- to 3-fold and 9- to 12-fold, respectively. Peroxisomal catalase activity was unchanged, whereas the microsomal and cytosolic activities were increased 2- to 3-fold and 6- to 16-fold, respectively. These treatments also induced microsomal omega-hydroxylation of lauric acid 7-fold and soluble epoxide hydrolase activity in the mitochondrial and cytosolic fractions, as well as microsomal epoxide hydrolase activity about 50-100%. The only significant differences observed between the effects of (+)-2-ethylhexanoic acid and its (-)-enantiomer were on peroxisomal palmitoyl-CoA oxidation and lauroyl-CoA oxidase activity after 4 days of treatment. In both these cases the (+)-enantiomer resulted in increases which were 50-75% greater than those seen with the (-)-form.

Effects of perfluoro fatty acids on peroxisome proliferation and mitochondrial size in mouse liver: dose and time factors and effect of chain length

1. Male mice were fed a diet containing perfluoro fatty acids of varying chain length (i.e. perfluoroacetic, -butyric, -octanoic and -decanoic acids) at different doses (0.02 or 0.1% w/w of diet) for different periods of time (2-10 days), and effects on liver weight, hepatic mitochondrial protein and hepatic peroxisomal palmitoyl-CoA oxidation, lauroyl-CoA oxidase and catalase were monitored. 2. The greatest effects were obtained with perfluoro-octanoic and perfluoro decanoic acids, while perfluoro acetic acid was inactive. The effects with 0.02% w/w of diet perfluoro-octanoic acid were at least as great as those observed with 0.1%. A more detailed dose-response investigation focused on perfluoro-octanoic acid revealed that maximal effects with this substance could be obtained with a dietary dose of 0.01% for 10 days and that significant changes were also observed with 0.001%. 3. Maximal effects with 0.02% w/w of diet perfluoro-octanoic acid were attained after 6-10 days of feeding. 4. As with other peroxisome proliferators, perfluoro fatty acids increase mouse hepatic peroxisomal fatty acid beta-oxidation more extensively than they increase catalase, thus increasing hepatic oxidative stress. 5. As with other peroxisome proliferators, perfluoro fatty acids increase mouse liver mitochondrial protein. This effect is due primarily to a redistribution of mitochondria from the nuclear to the mitochondrial fraction, caused by an apparent decrease in the mean size of hepatic mitochondria after treatment.

Salvage trial of trimetrexate-leucovorin for the treatment of cerebral toxoplasmosis in patients with AIDS

The clinical efficacy of trimetrexate, a dihydrofolate reductase inhibitor with potent in vitro antitoxoplasma activity, was assessed in 9 sulfonamide-intolerant patients with AIDS and biopsy-proven cerebral toxoplasmosis. The 9 patients were treated for 28-149 days with trimetrexate (30-280 mg/m2/day) plus leucovorin (20-90 mg/m2 every 6 h). Radiographic responses were documented in 8 patients, and clinical responses in 5 patients. Despite continued therapy, all patients deteriorated clinically and radiographically within 13-109 days of their initial improvement. Trimetrexate at very high doses for extended periods was not associated with serious toxicity. Trimetrexate alone had dramatic but transient activity in sulfonamide-intolerant patients and thus is not adequate as single-agent therapy for AIDS-associated toxoplasmosis.

Formation of free radicals during phacoemulsification

During phacoemulsification cavitation bubbles are formed. These bubbles are believed to be one source of damage to corneal endothelium seen after phacoemulsification. Free radicals are induced whenever cavitation bubbles implode. The aim of this study was to confirm the initiation of free radicals by phacoemulsification and to correlate the power of ultrasound in the phacoemulsification process to the amount of free radicals formed, using both in vitro and in vivo techniques. The formation of free radicals was determined by adding luminol to a buffer and measuring the chemoluminescence in vitro and in rabbit eyes (Lumacounter 2080 or a single-photon-counting apparatus) during phacoemulsification. The data obtained show that free radicals are formed during phacoemulsification and that the amount of free radicals correlates with the power of ultrasound. Furthermore, the radical formation could be inhibited by the radical scavengers SOD, Healon and Healon GV. These results were achieved both in vitro in the test tube and in vivo in rabbit eyes. By showing that the addition of SOD to the irrigation buffer during phacoemulsification decreases the corneal endothelial cell damage, we show that free radicals could have a role in postoperative complications seen clinically.

Multiple genes encode the major surface glycoprotein of Pneumocystis carinii

The major surface antigen of Pneumocystis carinii, a life-threatening opportunistic pathogen in human immunodeficiency virus-infected patients, is an abundant glycoprotein that functions in host-organism interactions. A monoclonal antibody to this antigen is protective in animals, and thus this antigen is a good candidate for development as a vaccine to prevent or control P. carinii infection. We have cloned and sequenced seven related but unique genes encoding the major surface glycoprotein of rat P. carinii. Partial amino acid sequencing confirmed the identity of these genes. Based on Southern blot studies using chromosomal or restricted DNA, the major surface glycoproteins are the products of a multicopy family of genes. The predicted protein has an M(r) of approximately 123,000, is relatively rich in cysteine residues (5.5%) that are very strongly conserved, and contains a well conserved hydrophobic region at the carboxyl terminus. The presence of multiple related msg genes encoding the major surface glycoprotein of P. carinii suggests that antigenic variation is a possible mechanism for evading host defenses. Further characterization of this family of genes should allow the development of novel approaches to the control of this pathogen.

Glycosylation of the major human Pneumocystis carinii surface antigen

It has recently been shown that the major rat P. carinii surface antigen is important for initial host-organism attachment, possibly through binding to fibronectin, mannose-binding protein, or surfactant protein A. Since a carbohydrate/lectin interaction may be involved in adhesion, we undertook this study to characterize the glycosylation of the major human P. carinii surface glycoprotein (gp95). We have used purified gp95 as a source of antigen, and in lectin binding and deglycosylation studies it was found that approximately 9% of gp95 consists of N-linked carbohydrates of mainly high-mannose and bisected complex-type glycans. Using a polyclonal antibody raised against purified gp95 and crossed affinoimmunoelectrophoresis and the lectins Con A and WGA, gp95 exhibited carbohydrate-dependent microheterogeneity. We therefore suggest that gp95 is composed of subtypes which differ in N-linked glycosylation.

Antibody response to a major human Pneumocystis carinii surface antigen in patients without evidence of immunosuppression and in patients with suspected atypical pneumonia

IgG and IgM antibodies to a purified human Pneumocystis carinii surface antigen (gp95) were measured in 694 serum specimens from two different population groups using an EIA technique. In a population of 441 patients with no evidence of immunosuppression, the percentage of persons positive for IgG antibodies to gp95 was significantly lower in the age group 1 to 9 years (30%, 23/77) compared to persons 10 to 19 years old (56%, 49/88). In the age group 1 to 14 years there was a significant correlation between the percentage of persons with IgG antibodies to gp95 and age. In 106 consecutive patients under evaluation due to atypical pneumonia, 76 patients showed no change in the titre of antibodies to Legionella spp. or Mycoplasma pneumoniae in two consecutive serum samples. Three of these 76 patients (4%) demonstrated an increase in the level of IgG antibodies to gp95 in the paired samples. One of these patients had a verified Pneumocystis carinii pneumonia, and the two others were elderly men in whom no microbiological diagnosis of the pneumonia was established. Thus, it is concluded that IgG antibodies to gp95 develop in the majority of nonimmunosuppressed persons before the age of 13. Furthermore, Pneumocystis carinii pneumonia should be considered in the differential diagnosis in patients suspected of having atypical pneumonia.

IgM response to a human Pneumocystis carinii surface antigen in HIV-infected patients with pulmonary symptoms

We have developed an ELISA to detect IgM antibodies to a major human Pneumocystis carinii surface antigen (gp95), and investigated the IgM response in 128 HIV-infected patients who underwent bronchoscopy for evaluation of pulmonary symptoms. Only 5 (4%) patients had IgM antibodies to P. carinii gp95. Four of the 5 patients with IgM antibodies also had IgG antibodies to gp95 and microbiologically proven P. carinii pneumonia (PCP). In 76/128 patients for whom serial samples were available, changes in antibody response were determined. In 3 patients we demonstrated an increase in IgM antibody response to gp95. These patients also showed an increase in IgG antibodies to gp95 and had microbiologically proven PCP. Prior to the development of the IgM response, IgG antibodies to gp95 were detectable in all 3 patients. Thus, HIV-infected patients with PCP seldom produce IgM antibodies to the major human P. carinii surface antigen. The increase in IgM response during the course of PCP observed in 3 patients suggests either reinfection with a new strain, or antigenic drift of an already acquired strain of P. carinii.

The involvement of selenium in peroxisome proliferation caused by dietary administration of clofibrate to rats

The effects of dietary treatment with clofibrate (0.5% w/w for 10 days) on the livers of selenium-deficient male rats were examined. The peroxisome proliferation (as determined by electron microscopy) in the livers of selenium-deficient animals was much less pronounced than in the case of selenium-adequate rats and no increase in peroxisomal fatty acid beta-oxidation (assayed both as antimycin-insensitive palmitoyl-CoA oxidation and lauroyl-CoA oxidase activity) was observed in the deficient animals. On the other hand, in selenium-deficient rats clofibrate caused increases in the specific activity of microsomal lauric acid omega- and omega-1-hydroxylation and an apparent change in mitochondrial size, seen as a redistribution of mitochondria from the 600 x g(av) pellet to the 10,000 x g(av) pellet, which were approximately 50% as great as the corresponding effects on control animals. Obviously, then, these three different effects of clofibrate are not strictly coupled and may involve at least partially distinct underlying mechanisms. Initial experiments demonstrated that peroxisome proliferation could be obtained by exposing primary hepatocyte cultures derived from selenium-deficient rats to clofibric acid (an in vivo hydrolysis product of clofibrate which is the proximate peroxisome proliferator), nafenopin or mono(2-ethylhexyl)phthalate. This finding suggests that selenium deficiency does not have a direct influence on the basic process(es) underlying peroxisome proliferation, but rather has indirect effects, influencing, for example, the pharmacokinetics of clofibrate and/or hormonal factors.

Cellular reaction following cataract surgery with implantation of the heparin-surface-modified intraocular lens in rabbits with experimental uveitis

The inflammatory response after cataract surgery and intraocular lens (IOL) implantation was studied in rabbits with endotoxin-induced uveitis. On days 1, 3, 7, 14, and 30 postoperatively the rabbits were sacrificed and the number of white blood cells in the aqueous humor and cellular deposits on the IOLs were estimated. On days 14 and 30 the rabbits also had slitlamp examination to study the clinical outcome of the surgery. At day 1 after lens extraction and IOL implantation, the number of white blood cells in the aqueous humor was significantly lower (P < .05) in eyes with heparin-surface-modified (HSM) IOLs (795.2 +/- 262.9; mean +/- SEM) than in eyes with poly(methyl methacrylate) (PMMA) lenses (1386.5 +/- 247.9). No differences were seen at day 3, 7, 14, or 30 postoperatively. The choice of IOL material had no effect on the amount of cell deposits on the IOL surface or on clinical parameters such as anterior synechias, posterior synechias, fibrosis, and posterior capsular opacification. There was a trend toward a greater number of cellular deposits on the PMMA lenses, but this was not statistically significant. This study provides further evidence of improved biocompatibility of the HSM PMMA lens, as demonstrated by a decreased acute inflammatory response.

Breast carcinoma growth rate described by mammographic doubling time and S-phase fraction. Correlations to clinical and histopathologic factors in a screened population

BACKGROUND

In a retrospective study, correlations among mammographic doubling times (DT), clinicopathologic prognostic factors, and cytometric predictors were examined.

METHODS

One hundred fifty-eight patients with the possibility to calculate mammographic tumor DT were selected and the tumors were histologically reexamined and flow cytometric analysis for ploidy and S-phase fraction (SPF) was performed.

RESULTS

The tumors were Stage I in 68%, and 45% were detected by mammographic screening. DT ranged from 0.6 months to an indefinite time (median, 9.0 months). Short DT was significantly correlated to large tumor size (P = 0.01) and advanced pathologic tumor stage (P = 0.016), but there was no correlation between DT and histologic grade. Ploidy analysis indicated that there were 57% aneuploid and 7% tetraploid tumors. There was a significant overrepresentation of euploid tumors among tumors smaller than 10 mm (P = 0.02). Ploidy was correlated to histologic grade (P less than 0.001) and DT (P = 0.009). SPF was calculated in 122 cases. SPF correlated significantly with pathologic stage (P = 0.002), tumor size (P = 0.037), histologic grade (P = 0.001), the presence of axillary lymph node metastases (P = 0.046), DT (P = 0.02), and DNA ploidy (P less than 0.001). Compared with interval carcinoma, screening-detected carcinoma showed favorable characteristics concerning size, stage, DT, ploidy, and SPF but not regarding histologic grade and axillary lymph node metastases.

CONCLUSIONS

DT shows great variations. Factors related to tumor biology (i.e., DT, DNA ploidy, and SPF) are strongly correlated with one another, but they have no correlation with axillary lymph node metastases. Cancer detected by screening is discovered at an early stage and shows favorable characteristics concerning DT, ploidy, and SPF.

Mammographic growth rate, DNA ploidy, and S-phase fraction analysis in breast carcinoma. A prognostic evaluation in a screened population

BACKGROUND

The authors examined prognostic factors in 158 cases of breast carcinoma with known mammographic tumor volume doubling times (DT).

METHODS

The tumors were retrospectively reexamined histologically and flow cytometric analysis of DNA ploidy and S-phase fraction (SPF) was performed on archival paraffin-embedded material in each case. Life tables and Cox multivariate analyses were used for statistical evaluation of prognostic factors.

RESULTS

In univariate analysis of survival data, clinical and pathologic stage, histologic grade, the presence of axillary lymph node metastases, and SPF were significant prognostic predictors, but mammographic DT and DNA ploidy were not. SPF also contributed prognostic information in the subgroup of carcinoma cases detected by screening. In a Cox multivariate analysis, SPF, the presence of axillary lymph node metastases, and Stage II-III disease (as opposed to Stage I disease) were independent significant predictors of survival. In univariate analyses of distant disease-free survival, clinical and pathologic stage, tumor size, histologic grade, the presence of involved axillary nodes, DT, and SPF all were significant prognostic factors.

CONCLUSIONS

SPF, stage, and lymph node status were important prognostic factors in this patient material with predominantly small and node-negative breast carcinomas, whereas DNA ploidy and mammographic DT provided less prognostic information. The prognosis of carcinoma detected during screening did not differ significantly from that of breast carcinoma discovered otherwise in this selected patient group.

Effects of perfluoro fatty acids on xenobiotic-metabolizing enzymes, enzymes which detoxify reactive forms of oxygen and lipid peroxidation in mouse liver

Male mice were exposed via their diet to perfluoro fatty acids of various chain-lengths (2-10 carbon atoms) at different doses (0.02 and 0.1% weight) and for different periods of time (2-10 days). Thereafter, we monitored effects on liver and body weights and a number of hepatic parameters, including mitochondrial protein content, microsomal contents of cytochromes P450 and b5, NADPH-cytochrome P450 reductase activity [measured as NADPH-cytochrome c reductase (EC 1.6.2.3)], microsomal and cytosolic epoxide hydrolase (EC 3.3.2.3) activities, cytosolic DT-diaphorase (EC 1.6.99.2), glutathione transferase (EC 2.5.1.18), glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities, and levels of thiobarbituric acid-reactive material (as an indicator of lipid peroxidation) in the mitochondrial subfraction. The most dramatic changes observed were a 5-9-fold increase in mitochondrial protein, a 3-6-fold increase in the microsomal content of cytochrome P450, a 3-10-fold increase in cytosolic DT-diaphorase activity, an approximately 2-fold increase in cytosolic epoxide hydrolase activity and as much as a 60% decrease in the level of thiobarbituric acid-reactive compounds in the mitochondrial fraction. Smaller increases in microsomal epoxide hydrolase activity and decreases in cytosolic glutathione peroxidase activity were also observed. Of the perfluoro fatty acids tested, perfluorooctanoic acid caused the largest changes in the parameters examined here. Dietary exposure of mice to a 0.02% dose of this substance for 10 days results in a maximal or near-maximal effect in most cases.

Is the cytosolic catalase induced by peroxisome proliferators in mouse liver on its way to the peroxisomes?

Dietary treatment of male C57B1/6 mice with clofibrate, nafenopin or WY-14.643 resulted in a modest (at most 2-fold) increase in the total catalase activity in the whole homogenate and mitochondrial fraction prepared from the livers of these animals. On the other hand, the catalase activity recovered in the cytosolic fraction was increased 12- to 18-fold, i.e. 30-35% of the total catalase activity in the hepatic homogenate was present in the high-speed supernatant fraction after treatment with these peroxisome proliferators. A study of the time course of the changes in peroxisomal and cytosolic catalase activities demonstrated that the peroxisomal activity both increased upon initiation of exposure and decreased after termination of treatment several days after the increase and decrease, respectively, in the corresponding cytosolic activity. This finding suggests that the cytosolic catalase may be on its way to incorporation into peroxisomes.

Antibody responses to a major Pneumocystis carinii antigen in human immunodeficiency virus-infected patients with and without P. carinii pneumonia

Antibody responses to a major purified human Pneumocystis carinii surface antigen (gp95) were determined by ELISA in human immunodeficiency virus (HIV)-infected patients. Serum IgG directed against gp95 was measured in 129 consecutive HIV-infected patients who underwent bronchoscopy for evaluation of pulmonary symptoms. Significantly more patients with P. carinii pneumonia (PCP) had detectable antibodies compared with HIV-infected patients without PCP and with HIV-negative controls (50 [66%] of 76 vs. 18 [34%] of 53 and 7 [35%] of 20, respectively; P less than .001), and the level of antibody response was higher (mean optical density ratio: 0.6 vs. 0.23 and 0.2, respectively; P less than .01). Changes in antibody response were investigated in 78 patients for whom serial serum samples taken around the time of bronchoscopy were available. Of the 47 patients with verified PCP, 20 (43%) mounted an antibody response, compared with only 1 (3%) of 31 patients without PCP (P less than .001). This patient had PCP on the basis of clinical criteria, including response to therapy. Thus, despite severe immunosuppression, a proportion of HIV-infected patients with PCP can mount a specific IgG-mediated antibody response to P. carinii.

Fibrinous reaction on implanted intraocular lenses. A comparison of conventional PMMA and heparin surface modified lenses

We studied the fibrinous reaction after intraocular lens (IOL) implantation in the posterior chamber of cynomolgus monkeys. In 50% of the eyes, we implanted an IOL made of conventional poly-(methyl methacrylate) (PMMA); in the remaining eyes we implanted a PMMA IOL with a heparin modified surface. Two, 4, 8, and 18 weeks after surgery the eyes were examined by slitlamp for fibrinous reactions on and around the IOL surface. At weeks 4, 8, and 18 there was a marked decrease in fibrinous reaction in the eyes with a heparin surface modified IOL. The results of this study accord with earlier findings that heparin surface modification improves the biocompatibility of the IOL.