Cefixime absorption kinetics after oral administration to humans

Cefixime (CFX) absorption kinetics after oral administration to humans was studied. Four distinct models, incorporating a delay of absorption and first-order elimination kinetics, i.e. first-order absorption (M1), zero-order absorption (M0), Michaelis-Menten type absorption (MM) and Michaelis-Menten type absorption with 'an absorption window' (MM-delta t) were used to fit concentration data of CFX in 10 Chinese men following an oral dose of 400 mg. r2 and AIC were selected as measures of goodness-of-fit. The results show that the MM-delta t model provided a better fit than the other three models. The kinetic parameters were estimated as follows: Vmax' = 10.80 +/- 3.80 mg.l-1.h-1; K(m)' = 88.31 +/- 2.75 micrograms.ml-1; delta t = 4.75 +/- 0.85 h; T1/2 = 4.20 +/- 0.92 h; Tmax = 5.20 +/- 0.92 h; and Cmax = 6.04 +/- 1.70 mg.l-1.

Microlamellar keratectomy for correction of high myopia

OBJECTIVE

To evaluate the preliminary results of high myopia correction by microlamellar keratectomy (MLK).

METHODS

Seventy-three eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00D to -32.00D (mean -18.45D +/- 6.18D). All the operations were performed with the special apparatus for MLK.

RESULTS

At 6 months after surgery, in the 73 eyes except 2 with new other symptoms, all the uncorrected visual acuity and corrected visual acuity were better than or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). No severe complications occurred during and after operation. The postoperative refractive status was stable.

CONCLUSIONS

MLK is effective to reduce high myopia and has some special advantages as compared with radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK). But influenced by several factors, the predictability of this procedure is merely fair. It is suggested that this kind of procedure must be done with excellent microsurgery equipments, microsurgical skills and much more clinical experience of managing corneal disorders.

Integrated approaches to the design of media and feeding strategies for fed-batch cultures of animal cells

Animal cell culture has become an important approach for the production of biologically functional proteins for human therapy. The quantity and quality of protein production are influenced by the culture environment, which is subject to change over the course of cell cultivation. Therefore, it is vital to design an optimal culture environment and control it within an optimal region to maximize the productivity. This requires that the factors affecting the culture environment (nutrient concentrations, by-product accumulation, pH and osmolality) and cell growth be integrated into the design of culture media for fed-batch animal cell cultures.

The natural history of borderline hypertension in a Chinese population

One hundred and thirty-one borderline hypertensive patients were followed up for 17 years. A cohort of normotensives strictly matched by age, sex, region and occupation served as controls (1:1). It was found that 64.6% of borderline hypertensive patients developed into established hypertensives after 17 years follow-up, 25.5% restored to normotensives and 13.8% remained unchanged. The total mortality rate of borderline hypertensives was higher than that of normotensives (27.9 vs 13.4/1000 person years), and the relative risk of total death in borderline hypertensives was 2.35. The main cause of death was stroke, accounting for 42.5% of the total death rate. The relative risk rates of occurrence and death associated with stroke were 8.3 and 11.6, respectively. It is concluded that the main complication of borderline hypertension was stroke rather than coronary heart disease, which was similar to that of established hypertension in this area. Part of the borderline hypertensives need to be treated to reduce the risk of cardiovascular complications.

Graphical evaluation of alkylation of myosin's SH1 and SH2: the N-phenylmaleimide reaction

Previous assertions about the effect of alkylation of SH1 and SH2 on the myosin high-salt calcium and EDTA ATPases have been summarized, and a simple procedure for obtaining the fractional labeling of SH1 and SH2 after treatment of myosin with alkylating agents has been derived. A simple graphical procedure for illustrating the degree of preference of a particular alkylating agent for SH1 over SH2 has also been developed. The procedures we developed were validated by applying them to two previously studied compounds, 4-(2-iodoacetamido)-TEMPO and 2,4-dinitrofluorobenzine, and then were used to determine a procedure for maximizing the extent of labeling of SH1 alone by N-phenylmaleimide, a compound not previously studied in this manner. It was found that approximately 80% of the SH1 sites could be alkylated without significant alkylation of SH2.

[A preliminary report of microlamellar keratectomy for correction of high myopia]

OBJECTIVE

To evaluate the preliminary results of high myopia corrected by microlamellar keratectomy (MLK).

METHODS

73 eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00 to -32.00 D (mean -18.45 +/- 6.18 D). All the operations were performed with a special apparatus made in America for MLK.

RESULTS

At 6 months after surgery, in the 73 eyes with complete data, all the uncorrected visual acuity and corrected visual acuity were betterthan or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). The correction of refraction in 63 eyes (86.30%) was within +/- 4.00 D of the intended correction. No severe complications occurred during and after operation. The postoperative status of refraction was stable.

CONCLUSIONS

MLK is effective in high myopia treatment and has some special advantages compared with radial keratotomy, photorefractive keratectomy, automated lamellar keratoplasty and excimer laser in situ keratomileusis. But the procedure is influenced by several factors, and the predictability of this procedure is merely fair. The authors suggest that this kind of procedure be done with excellent microsurgery equipment, microsurgical skills and much more clinical experiences in managing corneal disorders.

Assay of plasma homocysteine: light sensitivity of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid derivative, and use of appropriate calibrators

The recognition of homocysteine as a vascular risk factor has led to increased clinical interest in assaying plasma homocysteine concentrations. Our aim was to improve the reliability of a widely used assay based on HPLC of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid (SBD) derivative. We found that SBD derivatives of homocysteine, cysteine, and N-acetylhomocysteine were highly unstable in light but essentially stable in the dark for several hours at either 0 degree C or 25 degrees C. As our primary calibrator, we chose homocystine added to human serum for more consistent results than homocysteine or homocystine in an aqueous buffer. N-acetylcysteine was effective as an internal recovery standard. We observed a previously unreported peak with a prolonged elution time in some plasma samples from subjects who had ingested methionine. Our findings suggest improvements in this and other assay procedures for plasma homocysteine.

Assay of plasma homocysteine: light sensitivity of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid derivative, and use of appropriate calibrators

The recognition of homocysteine as a vascular risk factor has led to increased clinical interest in assaying plasma homocysteine concentrations. Our aim was to improve the reliability of a widely used assay based on HPLC of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid (SBD) derivative. We found that SBD derivatives of homocysteine, cysteine, and N-acetylhomocysteine were highly unstable in light but essentially stable in the dark for several hours at either 0 degree C or 25 degrees C. As our primary calibrator, we chose homocystine added to human serum for more consistent results than homocysteine or homocystine in an aqueous buffer. N-acetylcysteine was effective as an internal recovery standard. We observed a previously unreported peak with a prolonged elution time in some plasma samples from subjects who had ingested methionine. Our findings suggest improvements in this and other assay procedures for plasma homocysteine.

Diltiazem concentrations in plasma vs PR intervals on electrocardiogram in 8 men

AIM

To develop an acute tolerant model in describing relationship between diltiazem (Dil) concentrations in plasma and PR intervals on ECG in men.

METHOD

Both plasma concentrations of Dil and changes of ECG were simultaneously determined after po Dil 90 mg in 8 men.

RESULTS

A two-compartmental pharmacokinetic model with first-order input gave a good fitting for the plasma concentration of Dil. Corresponding pharmacokinetic parameters were estimated: t1/2 beta, 5.9 +/- 1.0 h; MRT, 15.9 +/- 1.0 h; t0, 0.38 +/- 0.07 h; tmax, 2.7 +/- 0.4 h, and Cmax, 161 +/- 60 micrograms.L-1. The good fittings for plasma concentration-effect data were obtained with tolerant model E = S x C/(1 + T/T50). The pharmacodynamic parameters were given as follows: S, 829 +/- 293 s.g-1.L; Kt0, 0.037 +/- 0.024 h-1 and T50, 10 +/- 4 micrograms.L-1.

CONCLUSION

Relationship between Dil concentrations in plasma and PR interval changes in men after po 90 mg was described using an acute tolerant model.

Weibull function fits to pharmacokinetic data of ribavirin in man

Weibull function C = Bts-1exp(-lambda ts) was used to describe plasma concentration-time data of ribavirin in 6 healthy subjects following an i.v. dose of 600 mg. A good fit was found in each of the subjects, where the coefficients of determination r2 were > 0.99. The parameters estimated were as follows: B, 5.90 +/- 1.86 micrograms.h1-s; lambda, 0.607 +/- 0.156 h-s; and s, 0.339 +/- 0.085, respectively. The results were compared with those by triexponential function. By providing lower values of AIC and SD, as well as higher values of r2, the Weibull function proved to be superior to triexponential function for data of 3 subjects. These results indicated that both Weibull function and triexponential function provided a good fit of plasma concentration-time data of ribavirin in man following an i.v. dose.

Effect of captopril on intracellular free calcium ([Ca2+]i) of thymocytes in spontaneously hypertensive rats

Hypertension is associated with dysfunction of the immune system. Intracellular free calcium ([Ca2+]i) was reportedly increased in immune cells, such as lymphocytes and thymocytes, both in hypertensive patients and in animals. To evaluate if captopril has an effect on the immune system, [Ca2+]i in thymocytes was monitored during the development of hypertension from 4-24 weeks, and after treatment with captopril for 4 and 12 weeks in spontaneously hypertensive rats (SHR). SHR (n = 24) were treated with captopril at a dose of 20 mg/kg/day at 12 weeks of age after establishment of hypertension. Untreated SHR (n = 17) and normotensive Wistar Kyoto (WKY n = 14) served as control. [Ca2+]i of thymocytes was measured using Fura-2. It was found that [Ca2+]i of thymocytes decreased both in SHR and WKY from 4-12 weeks of age. From 12-24 weeks, [Ca2+]i in thymocytes remained at a constant level in WKY. However, [Ca2+]i in thymocytes increased significantly in SHR after 12 weeks. Captopril (CAP) treatment significantly lowered [Ca2+]i in thymocytes derived from SHR at 24 weeks. This treatment was associated with a moderate reduction in systolic blood pressure. Established hypertension in SHR is associated with increased [Ca2+]i in thymocytes. This may be indicative of immunological dysfunction. Captopril inhibits the increase in [Ca2+]i of thymocytes in SHR.

[An experimental study on epikeratophakia]

OBJECTIVE

The study was designed to investigate the corneal changes at various times after epikeratophakia performed on rabbit cornea.

METHODS

The process of epithelial repair, or interlayer healing, the changes of endothelial cells and Langerhans cells (LC) in corneal epithelium were observed at different intervals after surgery by using histochemistry technique.

RESULTS

The epithelial repair of the graft was completed by 4-12 postoperative days. The repopulation of keratocytes was seen firstly at peripheral and superior part of the lenticule at 7-14 postoperative days and completed to normal by postoperative 2 months. No changes were observed in the endothelial cells. The proliferation of LC was observed in the limbal epithelium at day 3, reached the peak by day 14 and recovered to normal at month 2 postoperatively.

CONCLUSION

Epikeratophakia is available and safe, The proliferation of LC might result from wound healing not from immune rejection.

Serial measures of plasma homocyst(e)ine after acute myocardial infarction

To determine whether plasma levels of homocyst(e)ine are affected by the acute phase response, we studied 10 subjects serially after acute myocardial infarction. Our data indicate that measurement of homocyst(e)ine in patients with myocardial infarction should ideally be deferred for 7 days if spuriously low levels are to be averted.

Reversible thermal denaturation of staphylococcal nuclease: a Fourier transformed infrared spectrum study

The secondary structures of staphylococcal nuclease (SNase) have been assigned and semiquantitatively estimated from the deconvoluted Fourier transformed infrared (FTIR) spectrum. The changes in the secondary structures accompanying unfolding and refolding of SNase during reversible thermal denaturation up to 70 degrees C are followed by FTIR measurements. Only slight perturbation was observed up to 35 degrees C. The unfolding transition temperatures of beta-structure and alpha-helix are almost the same at 48.0-48.5 degrees C. During refolding the formation of the beta-structure follows the same pathway but that of the alpha-helix does not, although it recovers its original content almost completely. The final thermally denatured state at high temperature (60-70 degrees C) contains nonrandom structures in the complicated interaction, energetically resembling many kinds of structures. The occurrence of local conformational change before the final cooperative transition to the unfolded state during thermal denaturation as judged by FTIR spectra indicates that the unfolding and refolding of SNase may not follow the typical two-state model.

A chemiluminescence immunoassay for evaluation of Cryptosporidium parvum growth in vitro

A chemiluminescence immunoassay (CLIA) was developed to detect Cryptosporidium parvum growth in Madin-Darby canine kidney (MDCK) cell cultures. Optimal results were obtained when MDCK cells were plated at a density of 1 x 10(4) cells/well (96-well plate) and maintained as a monolayer for 4 days prior to infection with 2 x 10(4) parasites/well. Two compounds (paromomycin and maduramicin) were evaluated and shown to have selective activity against C. parvum in a dose-dependent manner. There was excellent correlation between CLIA and immunofluorescence assay when assessing anti-C. parvum agents in MDCK cells. CLIA offers advantages over conventional enzyme-linked immunosorbent assay and immunofluorescence assay methods in that it is more sensitive and efficient. The combination of CLIA and MDCK culture provides an efficient tool for evaluating potential anti-cryptosporidial compounds prior to testing in animal models.

In vitro anticryptosporidial activity of dinitroaniline herbicides

Despite the evaluation of over 100 antimicrobial drugs, the diarrheal disease cryptosporidiosis has remained refractory to treatment. We report the evaluation of five dinitroaniline herbicides including trifluralin, profluralin, nitralin, pendimethalin, and fluchloralin for anticryptosporidial activity in an in vitro cultivation model of Cryptosporidium parvum. All five compounds exhibited significant anticryptosporidial activities with no corresponding evidence of toxicity. The most active compound was pendimethalin with an IC50 of 0.19 microM while nitralin was the least active with an IC50 of 4.5 microM. These compounds should be evaluated further in an animal model of cryptosporidiosis.

Cataract extraction and intraocular lens implantation with anterior vitrectomy in children

OBJECTIVE

Extracapsular cataract extraction (ECCE) with selective intraocular lens (IOL) implantation has been the choice of the treatment for children with cataracts. With regard to surgical technique, ECCE with anterior segment vitrectomy has shown some success in reducing complications. Formation of a secondary membrane and opacity of the posterior capsule, however, are still major postoperative complications. To reduce these complications, we modified current surgical procedures with minimal incisions and manipulations.

PATIENTS AND METHODS

ECCE with anterior segment vitrectomy was performed using Storz Protage's system in 84 eyes of 58 children ranging in age from 14 months to 14 years. Of 70 eyes of children aged above 3 years, IOLs were implanted simultaneously. Vision improvement and incidence of postoperative complications were compared with other standard procedures to determine the benefits of the operation for children with cataracts. After the anterior capsule was opened by continuous circular capsulorhexis or envelope-form capsulectomy, the lens cortex was excised. Subsequently, the IOL was implanted into the bag.

RESULTS

Nine-30 months follow-up showed that all of the central area of the posterior capsule remained clear except one eye in which a secondary membrane was partially formed on the anterior surface of vitreous. No other operative or postoperative complications occurred.

CONCLUSIONS

The results indicate that the modified procedure is beneficial in the prevention of secondary cataract formation and other postoperative complications in a short term follow-up, however, a long-term follow-up is warranted to evaluate its role in pediatric cataract surgery.

[Penetrating keratoplasty in children]

OBJECTIVE

The study was designed to approach the operative techniques of penetrating keratoplasty (PKP) in children and the influential factors on the rate of graft clarity.

METHODS

PKP was performed on 33 eyes of 30 children whose corneal opacities resulted from various causes and they were followed for 6 months to 3 years.

RESULTS

The rate of graft clarity was 66.7% and 44.8% of these eyes were relieved from blindness. The poorest results achieved were in cases with congenital corneal opacity and the main cause of graft failure is endothelial immune rejection.

CONCLUSION

Although the surgical results in children are poorer than that in adults, from the concern of prevention of amblyopia and cosmetic problem, it is necessary to perform the operation earlier.

[A preliminary report on extracapsular cataract extraction with intraocular lens implantation in children]

Extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (IOL) implantation was performed on 94 eyes of children who were followed up for 6 approximately 30 months. IOLs were inserted in all of these eyes successfully with anterior vitrectomy used in several cases with traumatic cataract. The postoperative managements were similar to those in adults, but their complications were severer obviously than those of adults. Uveitis was the main postoperative complication which was characterized by severer anterior chamber reaction, longer duration and easier to form posterior iris synechiae and develop posterior capsular opacity. The follow-up results showed that the unilateral recovery rate from blindness is 90.1%, and 49.4% of these patients' corrected visual acuities were below 0.4. Because of the controversy on IOL implantation in children, it is the authors opinion that it should be cautious to perform IOL implantation on children and such an operation is not advocated for children under 3 years old. Children with unilateral cataract should be managed by experienced doctors, and it is very important to follow up carefully, to correct refractive error and carry out amblyopia treatment.

[An experimental study on HSV-1 corneal latency by in situ nucleic acid hybridization]

An experimental study was performed on animal models for evaluation of the possibility of herpes simplex virus-1 (HSV-1) corneal latency by in situ nucleic acid hybridization. 20 normal New Zealand white (NZW) rabbits were used, and 3 x 10(6) PFU/ml of McKrae strain HSV-1 was inoculated bilaterally into the corneal stroma in 14 rabbit eyes. Of the 28 eyes, 22 developed typical herpes simplex keratitis (HSK). On the postoperative 60th day, 4 corneas with latent infection were transplanted into one unilateral eyes of each 4 non-infected NZW rabbits respectively and removed 2 weeks postoperatively. The corneal buttons were individually detected for the presence of HSV-1 antigen and nucleic acid sequences by using clonal IgG HSV-1 antibody and biotinylated HSV-1 DNA probe respectively. The results showed that the HSV-1 DNA sequences retained only within the corneal stromal layer with negative HSV-1 antigen staining. These results strongly suggest that the cornea be capable of harboring latent HSV-1.

A study on HSV-1 corneal potential infection by in situ nucleic acid hybridization

PURPOSE

To evaluate the possibility of HSV-1 corneal latency by in situ nucleic acid hybridization in animal models.

METHODS

20 normal New Zealand White (NEW) rabbits were used, 14 of them were inoculated bilaterally with 3 x 10 PFU/ml of McKrae strain HSV-1 by intrastromal injection. 22/28 eyes developed typical herpes simplex keratitis (HSK) diseases. At 60 day postoperation (PI), 4 latent corneas were transplanted to one eye of 4 noninfected NZW rabbits and removed 2 weeks PI. Corneas at all time intervals of infection and two weeks after PKP were detected for presence of HSV-1 antigen and nucleic acid sequences by using clonal IgG HSV-1 antibody and biotinylated HSV-1 DNA probe individually.

RESULTS

The results showed that the HSV-1 DNA sequences were retained within the corneal epithelium and anterior stromal keratocytes during acute diseases, while the corneas during latent infection and postoperation, the HSV-1 DNA sequences were retained only within the stromal layer with negative HSV-1 antigen staining.

CONCLUSIONS

These results strongly suggest that the cornea may be capable of harboring latent HSV-1.

[A preliminary report of small incision cataract surgery by phacoemulsification]

The results of 34 cases with cataract extracted by phacoemulsification were preliminarily reported. Postoperatively, they achieved corrected visual acuities > 1.0 in 24 eyes (70.59%) in one week and in 25 eyes (73.53%) after 3 months. The post-operative astigmatism showed a tendency of change from with-the-rule shifting to against-the-rule. The rate of the corneal endothelial cell loss was 13.28%. No severe intra- and post-operative complications were found. It is concluded that the small incision, slight post-operative reaction and fast visual rehabilitation inherent in phacoemulsification procedures are more beneficial to patients than the conventional extracapsular cataract extraction.

Anti-AIDS (acquired immune deficiency syndrome) agents. 17. New brominated hexahydroxybiphenyl derivatives as potent anti-HIV agents

Sixteen biphenyl derivatives were synthesized and evaluated for their inhibitory activity against HIV-1 replication in acutely infected H9 cells. 3-Bromo- (4) and 3,3'-dibromo-4,4'-dimethoxy-5,6,5',6'-bis(methylenedioxy)-2,2'- bis(methoxycarbonyl)biphenyl (5) demonstrated potent anti-HIV activity with EC50 values of 0.52 and 0.23 micrograms/mL and therapeutic index values of > 190 and > 480, respectively. A comparison of the anti-HIV activity of these biphenyl derivatives suggested that the types of substituents on the phenolic hydroxy groups rather than the number of bromine(s) on the aromatic rings are important to the enhanced anti-HIV activity. Compounds 4 and 5 also showed potent inhibitory activity against HIV-1 reverse transcriptase in a template-primer dependent manner. The site of inhibition of HIV could be related to inhibition of this enzyme. Compounds 4 and 5 did not induce virus expression from the chronic HIV-1-infected cell lines ACH-2 and U1. Furthermore, these two agents did not inhibit an increase in virus production from the chronic HIV-1-infected cell lines when the phorbol ester PMA was present.

Comparative studies of the conformation of the N-terminal fragments of staphylococcal nuclease R in solution

In order to elucidate the folding of nascent peptide, five peptide fragments of staphylococcal nuclease R starting from N-terminal end and of different chain lengths are made by deletion of 47, 39, 28, 14 and 8 amino-acid residues from its C-terminal end, respectively. Changes in conformation of the N-terminal fragments have been compared by using Fourier-transform infrared spectra, far-ultraviolet circular dichroism spectra and analysis of surface hydrophobicity. The experiments indicate that all the five fragments have certain amounts of residual structure; in general, with increasing the peptide chain, the contents of secondary structure and the enzyme's activity of the peptide increase, and the exposed hydrophobic side chains brought about by the deletion of C-terminal residues are gradually buried in the interior of the nuclease. However, the ordered secondary structures do not always increase with increasing the peptide chain. Further growth of the length of the peptide chain could have an important effect on the conformation of the peptide fragment already synthesized, suggesting some structural adjustments should be necessary in order for the newly synthesized polypeptide to attain its final native conformation. These results support Tsou's nascent peptide folding hypothesis (Tsou, C.-L. (1988) Biochemistry 27, 1809-1812).

[A clinical observation on intraocular lens implantation in high myopic eyes with cataract]

Extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation was performed on 124 high myopic eyes with cataract of 101 cases whose mean period of follow-up was 16.4 months. Post-operatively, 95.97% of these eyes were relieved from blindness and 75.00%, from visual handicap. The incidence of posterior capsular opacity was 22.58% and only did 1.61% of the eyes occur retinal detachment. Intraoperatively, posterior capsular rupture occurred in 5.65% of the eyes. The results indicate that ECCE with IOL implantation performed on eyes with high myopia and cataract is effective.

The impending Canadian prostate cancer epidemic

PURPOSE

To model and forecast prostate cancer incidence and mortality in Canada to the year 2016.

METHODS

Bivariate multiplicative models of prostate cancer incidence and mortality for Canadian men aged 45 years or older, linear in time and Weibull in age, were fitted using weighted non-linear regression.

RESULTS

The number of incident cases of prostate cancer is forecast to increase from 11,355, observed in 1990, to 26,900 by the year 2010 and to 35,200 by the year 2016. The number of deaths are estimated to climb from 3,424, observed in 1991, to an estimated 6,300 by the year 2010, and to 7,800 by the year 2016.

CONCLUSIONS

The dramatic increase in prostate cancer rates with age, coupled with the expected large increase in the elderly Canadian male population and steadily increasing prostate cancer incidence rates will produce very large increases in the number of men who will have prostate cancer over the next 20 years. This has important implications for health care delivery in the future.

[An investigation on therapeutic results of extracapsular cataract extraction and intraocular lens implantation in diabetics]

44 cases (50 eyes) with diabetes and cataract were followed up for 6-30 months after extracapsular cataract extraction (ECCE) with intraocular lens implantation (IOL). No severe intra- and post-operative complications were found and 84% of eyes obtained post-operative corrected visual acuities > or = 0.5. The results suggest that the pre-operative hyperglycemia alone be not a contraindication of the operation. Pre-operatively, if the diabetes of patients with cataract can be controlled by diet or hypoglycemic agent, their glucose level in the blood remains normal and stable for a period of time and there are no other systemic and ocular complications, ECCE with IOL can be performed on such patients and the therapeutic results of the operation can be safe and reliable.

A molecular-based magnet test for malaria

The molecular-based magnet test for malaria is shown to be more sensitive than the thin blood film test. The globally used thin blood film test is less sensitive because it uses preparation steps that result in the reduction of the absolute number of diagnostically pertinent erythrocytes. Several reports of diagnostic error with the thin film test and the thick film test have appeared in the literature. In marked contrast to the commonly accepted tests, the magnet test concurrently partitions and concentrates the infected erythrocytes present in the initial sample. The magnetic test permits a brief and sensitive microscopic-based enumeration of the malaria-infected erythrocytes in the enriched sample. Diagnostically pertinent hemozoin is simply identified through two of its specific molecular properties: paramagnetism and birefringence. The former property mediates the capture and enrichment of malaria-infected erythrocytes within the magnetic flux and the latter property manifests the characteristic birefringence demonstrated by polarized light.

[An experimental study on cultivation of human trigeminal ganglionic cell in vitro and its sensitivity to infection of herpes simplex virus type 1]

We firstly report an experimental study on the sensitivity of primary cultural human trigeminal ganglionic cells infected by herpes simplex virus type 1 (HSV-1) in different time-points. The results indicate that the neuron of human trigeminal ganglia is the most sensitive cell type, the antigen of HSV-1 replicates rapidly within the cytoplasm and cell nucleus, the fibroblasts and glia cells are infected partly by the virus. Therefore, perhaps the neuron is the main harboring cell type.

[The prognostic characteristics of hypertensive left ventricular hypertrophy in a rural population]

One hundred and twenty-six rural hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed up for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.59 +/- 1.00mmol/L). A cohort of age, sex, region and occupation matched hypertensives without LVH (HT, n = 163) and normotensives (NT, n = 275) served as controls. The major cause of death in rural hypertensives with ECG LVH in this study was stroke (56.8%). After stratification of BP, no significant difference of stroke risk was found between patients with LVH and hypertensives without LVH, while cardiovascular risk in the patients with LVH plus ST segment depression persisted. LVH per se seems not to be an independent factor for stroke. The high stroke rate in patients with LVH may be ascribed to the coexisting higher level of BP. After adjustment of coexisting hypertension, ECG LVH based on voltage only was not an independent risk factor of stroke and cardiovascular events, while LVH plus ST segment depression was closely related to cardiovascular events. In this low level, plasma cholesterol did not affect the mortality rate of stroke.

Applications of improved stoichiometric model in medium design and fed-batch cultivation of animal cells in bioreactor

In our previous work (Xie and Wang, 1994a), a simplified stoichiometric model on energy metabolism for animal cell cultivation was developed. Fed-batch experiments were performed in T-flasks using this model in supplemental medium design (Xie and Wang, 1994b). In this work, the major pathways of glucose and glutamine metabolism were incorporated into the stoichiometric model. Fed-batch culture was conducted in a 2-liter bioreactor with appropriate process control strategies. Nutrient concentrations, especially glucose and glutamine, were maintained at constant but low levels through the automated feeding of a supplemental medium formulated using the improved stoichiometric model. The formation of toxic byproducts, such as ammonia and lactate (Hassell et al., 1991), was greatly reduced. The specific lactate production rate was decreased by 62-fold compared with batch culture in bioreactor and by 8-fold compared to fed-batch culture in T-flask using the previous stoichiometric model. Ammonia formation was also decreased compared with both the batch and fed-batch cultures. Most importantly, the monoclonal antibody concentration reached 900 mg l-1, an increase of 17- and 1.6-fold compared with the batch and fed-batch cultures respectively.

The prognostic characteristics of hypertensive left ventricular hypertrophy in a population with low prevalence of hypertension and low plasma cholesterol

One hundred and twenty-six hypertensive patients with ECG left ventricular hypertrophy (HT-LVH) were followed for 10 years to investigate the prognostic characteristics in a population with low prevalence of hypertension (2.93%) and low plasma cholesterol (4.26 +/- 0.91 mmol/L). A cohort of age-, sex-, region- and occupation-matched, randomized hypertensives without ECG-LVH (n = 163) and normotensives (n = 275) served as controls. HT-LVH was found to be associated with an increased risk of overall death, stroke mortality and cardiovascular mortality. The major cause of death in rural hypertensives with ECG-LVH was stroke (56.8%). After adjusting BP and BP stratification, no significant difference of stroke risk was found between patients with and without LVH, while cardiovascular risk persisted in patients with LVH plus ST segment depression. LVH per se did not appear to be an independent factor for stroke death. Higher stroke mortality in patients with LVH may be ascribed to the coexisting higher level of BP. Furthermore, after adjusting for the coexisting hypertension, ECG-LVH in terms of voltage only was not related to the prognosis of stroke and cardiovascular death. The mortality rate of stroke was not affected by plasma cholesterol levels, as the levels seen were in a low range.

Comparison of secondary structures of insulin and proinsulin by FTIR

Although the structure of insulin is known in great detail, that of proinsulin has been little investigated, except for a few CD and NMR studies. The secondary structures of human proinsulin are now compared with those of insulin by Fourier Transformed Infrared (FTIR) studies. The deconvolved and second derivative spectra of proinsulin and insulin in the amide I' band region are closely similar with peaks corresponding to alpha-helix, irregular helix, and 3(10) helix at nearly identical positions. For both proteins, the relative contents of the above structures as calculated from the peak areas are in good agreement with the values obtained from the known structure of crystalline porcine insulin. However, compared with insulin, proinsulin has markedly more unordered structures as indicated by the area under the peak at 1643.4 cm-1. In addition, both peak positions and relative areas for turn structure of the prohormone are different from those for insulin. It appears from the above that the A-and B-chain segments of proinsulin and insulin are similar in their secondary structures, especially in helices. The C-chain segment is largely unordered except in a few beta-turns.

Histological distribution and developmental changes of tropomyosin isoforms in three chicken digestive organs

Histological localization of tropomyosin isoforms in three digestive organs from embryonic and adult chickens was performed by using rabbit antisera against chicken skeletal muscle tropomyosin and against low-Mr-type tropomyosin from chicken small intestine mucosa. The former antiserum (named TM-SH) reacted with alpha, beta, and high-Mr-type isoforms, and the latter (named TM-HL) reacted with alpha, beta, high-Mr-type and low-Mr-type isoforms, alpha and beta Isoforms were detected in muscle cells of the muscular layer and the muscularis mucosa. Low-Mr-type isoforms, however, were detected along the cell membrane and cytoplasm of almost all nonmuscle cells, especially in terminal webs of epithelial cells. Developmental changes of tropomyosin isoforms in digestive organs were studied by two-dimensional gel electrophoresis and image analysis. The relative amounts of alpha and beta isoforms increased in the course of development, but those of low-Mr-type and high-Mr-type isoforms decreased.

Effect of dizocilpine maleate on cerebral anoxia and ischemic damage in rodents

The Protective effects of dizocilpine maleate (DM) against anoxia in mice and ischemic damage in rats of 4-vessel occlusion (4-VO) were studied. DM 0.5 or 1.0 mg.kg-1 ip significantly prolonged the survival time of mice in closed containers. DM 0.5 and 1.0 mg.kg-1 ip 30 min prior to 4-VO obviously accelerated the electroencephalographic recovery, reduced the neuronal loss in the hippocampus, and increased the survival rate after 72-h reperfusion. These effects followed a dose-dependent manner. Our results indicate that selective non-competitive N-methyl-D-aspartate receptor blocker DM protects against anoxic and ischemic cerebral damage.

Effect of dizocilpine maleate on monoamines and their metabolites in rat brain

Systemic (ip) injection of dizocilpine maleate (DM, 0.1 and 0.5 mg.kg-1) increased the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid but did not bring about any noticeable change in the dopamine (DA) level in the striatum and limbic area. DM also increased the levels of norepinephrine in the limbic area and 5-hydroxyindoleacetic acid in the hippocampus. Amphetamine increased DA level and reduced DOPAC level in the striatum and limbic area. The behavioral manifestations revealed that DM predominantly evoked circling behavior and ataxia. The results indicate that the mechanism of the behavioral effect of DM may be different from that of amphetamine.

The pairing of the separated A and B chains of insulin and its derivatives, FTIR studies

From the amide I bands of their deconvolved FTIR spectra, the S-thiomethyl derivatives of the insulin A, B, despentapeptide(26-30) B and desoctapeptide(23-30) B chains all contain significant amounts of ordered secondary structure. The intact B chain is considerably more ordered than either the A or the truncated B chains. Comparison of the spectra of the separated and mixed intact chains of insulin suggests further folding upon mixing of the chains leading to significant increases in ordered secondary structures, presumably because of stabilization by interaction of the chains. The interactions of the A chain with the DPI B chain appear to be weaker as compared to that with the intact B chain. The above results suggest that only the intact A and B chains contain sufficient structural information to recognize each other and interact to form a native-like structure which make the correct formation of the disulfide linkages possible.

Effect of intrahippocampal quinolinic acid infusion on the amygdala kindling in rat

The effect of intrahippocampal infusion of quinolinic acid (Quin), an endogenous excitatory amino acid, was studied on the amygdala kindling. Quin 120 nmol injected intrahippocampally 2 wk prior to the beginning of amygdala kindling significantly not only produced dorsal hippocampal pyramidal and granule cell loss but also decreased the number of stimuli to trigger the stage 5 seizures of amygdala kindling. In kindled rats, intrahippocampal 20 nmol Quin infusion fully inhibited the stage 5 of amygdala-kindled seizures. The inhibitory effect of Quin was antagonized by dl-2-amino-7-phosphonoheptanoic acid, a selective antagonist of N-methyl-D-aspartate (NMDA) type receptors. The results suggest that NMDA-type receptors in the hippocampus may play a role in the control of the seizure threshold in the amygdala.

Identification and distribution of tropomyosin isoforms in chicken digestive canal

Two-dimensional gel electrophoresis of eight digestive organ extracts from 60-day-old chicks was performed. Judging from the similarity of their protein maps, the organs were classified into the following four types: 1) esophagus type, 2) proventriculus type, 3) gizzard type, and 4) intestine type. In four representative organs of these types, the distribution of tropomyosin isoforms was examined, and four high- and five low-Mr-type isoforms in addition to alpha and beta isoforms were detected in the embryonic organs. In the adult organs, however, there were three high- and four low-Mr-type isoforms, which were restricted to the mucous membrane, in addition to alpha and beta isoforms. Immunoblot analysis indicated that the high- and low-Mr-type isoforms in the embryo corresponded with those in the adult mucous membrane, but differences in the number and amount of the isoforms were found between the embryo and the adult mucous membrane.