Rapid prenatal diagnosis of Hb Bart's hydrops fetalis in southeast Asia area by polymerase chain reaction

We used the polymerase chain reaction (PCR) to amplify the breakpoint area of alpha-thalassemia-1 of Southeast Asia type and several parts of the alpha-globin gene cluster to make a differential diagnosis between alpha-thalassemia-1 and Hb Bart's hydrops fetalis. The procedure involved three primers to detect the homozygote of alpha-thalassemia-1, then amplifies the other alpha-globin gene cluster with three other pairs of primers to double check the results. The PCR products were checked again by allele specific probes. Twenty-two cases were diagnosed prenatally, two were normal, 17 were alpha-thalassemia-1, and three Hb Bart's hydrops fetalis. All cases were confirmed either by Southern blot hybridization or follow-up by sonography or after delivery. No false positive or false negative results were obtained by our strigent procedure. We conclude it to be a rapid, accurate and economic method.

Detection of bcr/c-abl mRNA in chronic myelogenous leukemia by polymerase chain reaction to identify chromosome translocation

The hallmark of chronic myelogenous leukemia (CML) is the Philadelphia chromosome (Ph1) which is caused by a translocation of the c-abl gene from chromosome 9 to the breakpoint cluster region (bcr) on chromosome 22. Polymerase chain reaction (PCR) can be used to detect the chimeric bcr/c-abl mRNA as evidence of the translocation. We applied a very simple and quick method of isolating cytoplasmic RNA, as well as reverse transcription and PCR in detecting bcr/c-abl mRNA of seven CML patients in various stages. Our results showed that only a small amount of either peripheral blood or bone marrow material was required for the expression of the bcr/c-abl mRNA. This is a very fast and time-saving method since a one-step method of cytoplasmic RNA isolation is used instead of the several steps in total RNA isolation as published in other literature.

Detection of hemoglobin E heterozygotes by using polymerase chain reaction and direct DNA sequencing: report of a case

From an overseas Chinese born in Thailand, an extraordinarily high level of A2 + E band (20.2%) was found during routine cellulose acetate Hb electrophoresis. With a suspicion of Hb E, the beta-globin gene was studied by using the polymerase chain reaction (PCR) and direct DNA sequencing method. A 1.4 kb fragment covering the whole beta-globin gene was amplified by PCR. Sequence analysis of the amplified product revealed a GAG > AAG transversion at codon 26, which resulted in an amino acid substitution of lysine for glutamic acid. A normal sequence at the corresponding codon was noted in the other allele; hence, this patient is a heterozygote of Hb E. PCR and direct DNA sequencing provide a rapid method for detection of Hb E from a small amount of DNA.

Effect of dextran on predamaged corneal endothelium: an organ culture study

Dextran T500 was used as a supplement in organ culture medium to evaluate its effect on corneal endothelium with disseminated damage. After 1 week of culturing, the control group showed an intact endothelium throughout the entire cornea. However, in the dextran-supplemented group, multiple endothelial necroses were observed in 5 of 10 corneas. Besides, intracytoplasmic vacuoles and granules, deposits on the endothelial surface and widened intercellular spaces were quite numerous. The potential toxicity of dextran to degenerated corneal endothelial cells may be responsible for these findings.

The effects of epidermal growth factor and chondroitin sulfate on the animal corneal endothelial cell culture

In order to investigate the effects of different culture media containing various concentrations of epidermal growth factor (EGF) and chondroitin sulfate (CDS) on the growth of cultured corneal endothelial cell, pig corneal endothelial cells were used for this study. The cells were divided into 7 groups and each group was cultured with a medium containing: 1. Eagle's minimal essential medium with Earle's salt (EMEM) only; 2. EMEM + EGF (10 ng/ml); 3. EMEM + EGF (100 ng/ml); 4. EMEM + CDS (1 mg/ml); 5. EMEM + CDS (25 mg/ml); 6. EMEM + EGF (10 ng/ml) + CDS (1 mg/ml); 7. EMEM + EGF (100 ng/ml) + CDS (25 mg/ml), respectively. The results are shown below: (1) High concentration of EGF (100 ng/ml) stimulated the growth of pig corneal endothelial cells, shortened doubling time and the cells reached confluence earliest in group 3. But a low concentration of EGF (10 ng/ml) showed no effects on the growth of pig corneal endothelial cells. (2) A high concentration of CDS (25 mg/ml) might retard the growth of pig corneal endothelial cell, but a low concentration of CDS (1 mg/ml) has no retarding effects on the growth of pig corneal endothelial cells. (3) A high concentration of EGF could "antagonize" the CDS induced growth retarding effects of endothelial cells. (4) Those cells cultured with a medium containing high concentrations of EGF had more mitotic activity, including many prominent binuclear and polynucleolar cells. (5) The cells cultured with a medium containing high concentrations of CDS showed a more flat-shaped morphology under observation with a phase contrast microscope.(ABSTRACT TRUNCATED AT 250 WORDS)

Optical coherence tomography

A technique called optical coherence tomography (OCT) has been developed for noninvasive cross-sectional imaging in biological systems. OCT uses low-coherence interferometry to produce a two-dimensional image of optical scattering from internal tissue microstructures in a way that is analogous to ultrasonic pulse-echo imaging. OCT has longitudinal and lateral spatial resolutions of a few micrometers and can detect reflected signals as small as approximately 10(-10) of the incident optical power. Tomographic imaging is demonstrated in vitro in the peripapillary area of the retina and in the coronary artery, two clinically relevant examples that are representative of transparent and turbid media, respectively.

[A self-made corneal graft marker made from disposable trephine]

A homemade corneal marker was contrived from a Pharmacia Superblade disposable corneal trephine by cutting away one arm of the trephine and then bending the single remaining arm to an angle of 45 degrees to the handle. The radii of the trephines ranged from 6.5mm to 8.5mm, at successive increments of 0.25mm. In optical corneal grafts, this marker can be used to pinpoint the center of the cornea, thus providing more accurate centralization of the area to be grafted. In therapeutic corneal grafts, the marker provides a more accurate determination of the most suitable area to be grafted. Unnecessary removal of healthy tissue or incomplete removal of diseased tissue are thus avoided. This marker is made easily and at no additional expense, and show itself to be a useful instrument to accurately determine the graft area in corneal surgery.

Micron-resolution ranging of cornea anterior chamber by optical reflectometry

Noncontact, high resolution measurements of anterior eye structures using optical coherence domain reflectometry are described. Distances between intraocular structures are measured by directing a beam of short coherence length light onto the eye and performing an interferometric measurement on the optical group delay of reflected signals. Measurements of corneal thickness, corneal excision depth, and anterior chamber depth are demonstrated in vitro, and the location of tissue boundaries is resolved to within +/- 2 microns. The full-width-half-maximum longitudinal resolution is 10 microns. Sensitivities to reflected signals as small as 10(-10) of the incident power are achieved by heterodyne detection.

High-speed photography of Er: YAG laser ablation in fluid. Implication for laser vitreous surgery

The mechanism of Er:YAG laser-induced long-range damage in intraocular surgery was investigated using high-speed photography. A short pulse of 2.94-microns radiation delivered by an optical fiber into an aqueous medium causes rapid localized heating and vaporization and creates a bubble at the tip of the fiber. The size of the bubble depends on the pulse energy and is about 1 mm at 1 mJ. The shape of the bubble has multiple lobes, which can be attributed to the spiky output of the laser pulse. The expanding bubble can cause thermal and mechanical damage to tissues. In addition, laser spikes propagating through the bubble can strike and damage tissue on the distal side of the bubble. In both mechanisms the damage zone approximates the bubble size and can be greater than 1 mm, ie, 1000 times the steady-state absorption length of water at 2.94 microns. The authors discuss ways to reduce the damage zone by bubble confinement.

The role of serum-supplements in organ culture for pre-damaged corneal endothelium

Thirty-six pig corneas were shaken in 0.18% NaCl to induce disseminated corneal endothelial damage. After treatment, the corneas were divided and cultured in 3 different combinations of media to study the effects of serum-supplements in corneal endothelial regeneration. There were MEM+10% FCS (FCS-group; n = 10); MEM+10% Nu-Serum (Nu-group; n = 10) and MEM only (control group; n = 16). After one week of culturing, most of the corneas in all 3 groups, despite the pre-damage, kept intact endothelia. This means that the endothelia were repaired whether the sera were supplemented or not. The cell densities of each were 2,454 +/- 450 cells/mm2, 2,776 +/- 476 cells/mm2 and 2,627 +/- 558 cells/mm2 respectively. The differences between each group were statistically insignificant. The morphological findings were also without much difference. When considering the risk of serum induced hypersensitivity, FCS can be replaced by Nu-Serum in the organ culture medium for corneal preservation. Since the advantage of serum-supplements in medium-term organ cultures seems limited, the necessity of serum supplements should be further reevaluated.

Detection of beta-globin gene from single hairs

DNA can be extracted from hair shafts and hair roots. The content of DNA in hairs is usually limited: the root end of hairs may contain 0.5 micrograms DNA and shed hairs contain less than 10 ng DNA. DNA analysis with restriction fragment length polymorphism (RFLP) requires microgram amounts of DNA. Such DNA cannot be obtained from such samples as single hairs or blood stains. Even with a little amount of DNA, specific genes of DNA can be greatly amplified to more than 10(6)-fold in vitro by polymerase chain reaction (PCR). We extracted the DNA from a half, 1, and 2 hair roots and 4 hair shafts and amplified the DNA with primer pairs (5'-GCACCATTCTAAAGAATAAC-3', 5'-GGATTGTAGCTGCTATTAGC-3') of the beta-globin gene, covering part sequences of the IVS-2 region by using the polymerase chain reaction for 50 cycles. The electrophoresis of the PCR product revealed a 131 base pairs band. Finally, we hybridized the PCR product with an IVS-2 probe (5'-GGGTTAAGGCAATAGCAAT-3'). A fragment of the IVS-2 extending from nucleotide 612 to 742 of the beta-globin gene can be demonstrated in the slot blot filter of hair roots and hair shafts, but not in the 1 microgram of blood which was not amplified by PCR. Detection of the beta-globin gene from single hairs by using the PCR may be useful for the diagnosis of thalassemia from single hairs.

Effects of fibroblast growth factor and chondroitin sulfate on predamaged corneal endothelium. An organ culture study

Fibroblast growth factor (FGF) and chondroitin sulfate (CDS) were used as supplements in organ culture medium to compare the regeneration ability of corneal endothelium with scattered damages. After 1 week of culturing, cell densities in both FGF-supplemented and FGF + CDS-supplemented groups were not higher than the densities of the control groups. Cells in both groups showed polymorphism. In both CDS-supplemented groups, the corneas were thinner. The cell density in the group supplemented with only CDS was higher than that of the control group, but in the CDS + FGF-supplemented group the cell density was not higher than that of the control and the morphology was even worse. Combining of FGF and CDS in culture medium appeared to be disadvantageous.

[Solvent action of sodium hypochlorite on fresh and formalin fixed tissue: a biochemical approach]

Debridement of the root canal system has long been recognized as the critical phase of success in endodontic therapy. Because of the morphological complexity of most root canals, complete removal of the pulp tissue during the mechanical preparation of these root canals is often impracticable. Sodium hypochlorite is thus currently favored by most endodontists as the routine irrigant on account of its antimicrobial action and its capacity to dissolve fresh tissue together with necrotic tissues. Formocresol is another common medicament for endodontic treatment and is usually used for pulpotomy, pulpectomy and intracanal medication. Nevertheless, it was empirically believed that formocresol may interrupt the action of sodium hypochlorite in the dissolution of residual tissue. Therefore, the present study was undertaken to testify whether formocresol can substantially retard the solvent action of sodium hypochlorite by comparing the effectiveness of 5% sodium hypochlorite on fresh and formalin-fixed tissues. Connective tissue from the abdominal wall of Sprague-Dawley rats was cut into pieces weighing 0.05 g and measuring about 2 x 10 x 10 mm. A total of 20 pieces of tissue were collected and divided into two groups: 10 pieces were used immediately as the fresh-tissue group; the other 10 pieces were fixed in 10% formalin for 7 days as the fixed-tissue group. Each group was then immersed in 5 ml of 5% sodium hypochlorite for 60 seconds, and 1 ml was aspirated from each for assay. Dialysis was performed using 2 liters of double distilled water for a period of 4 hours with the water changed hourly.(ABSTRACT TRUNCATED AT 250 WORDS)

A model to induce scattered cell damage in the corneal endothelium

A model to induce scattered cell damage in the corneal endothelium was set up by shaking a pig cornea in a glass bottle with 0.18% NaCl. Disseminated endothelial-cell losses, whose amounts correlated with the durations of treatment, were observed in the corneas which were shaken for less than 8 min. Following organ culturing for 1 week, most of the corneas still possessed intact endothelia which means that even after the treatment the endothelium still keeps a normal regenerative ability. With this method of design, a good model is provided to study the regeneration of the corneal endothelium.

Size and genetic composition of long terminal repeat sequences in the mouse intracisternal A-particle gene 81

The intracisternal A-particle (IAP) genome is a retrovirus-like gene family. Over 1000 copies of IAP genes are dispersed throughout the mouse genome. The purpose of this study was to determine the nucleotide sequence of both ends of the long terminal repeat (LTR) units which bind the IAP gene 81. The results obtained showed that, whereas the structural domain and several genomic characteristics of the IAP 81 LTR units and other LTR structures of a given IAP gene were almost identical, the nucleotide sequences of these LTR units associated with different IAP gene were sometimes very different from each other. In the comparisons of different LTR structures, the transcriptional signals for promotion, initiation, polyadenylation and termination as well as several characteristic sequences of the Z-DNA region, enhancer core sequence and glucocorticoid-responsive element were all found to be present in IAP 81 LTRs. The possible roles of the primary nucleotide sequence of an LTR structure are discussed.

In vitro detection of plant mycoplasmas by immunofluorescent staining with monoclonal antibodies

Hybridoma techniques have been applied to develop specific monoclonal antibodies (McAbs) against spiroplasmas and mycoplasma-like organisms (MLOs). Advantages of the McAbs have been clearly demonstrated in the detection of aster yellows (AY) MLO by indirect enzyme-linked immunosorbent assay (ELISA) and immunofluorescent staining, compared with conventionally produced polyclonal antibodies. McAbs have also been applied in the in vitro detection and identification of spiroplasmas and AY MLOs on membrane filters using modified direct-count immunofluorescent staining. Organisms were fixed with glutaraldehyde and treated with McAbs and fluorescein isothiocyanate (FITC)-conjugated antimouse immunoglobulin, by incubating and concentrating them in a microcentrifuge tube before collecting them on polycarbonate membrane. This procedure best conserves the helical integrity of spiroplasmas without altering the configuration of surface antigens recognized by McAbs. This method could be valuable in monitoring the fastidious mycoplasmas during purification or cultivation attempts.

Nucleotide sequence analysis of cellular flanking regions of intracisternal A-particle gene 81

The cellular nucleotide sequences flanking the mouse intracisternal A-particle gene 81 were determined. The results indicated that they were made of many small oligonucleotide repeats both direct and indirect in orientation. These two different kinds of repeating sequences were often found to be overlap. The overall base composition of this region is relatively A + T rich. The most important feature of the sequences determined was that it consists of several repeated dinucleotide tracts containing a (CA)16 repeating cluster in the 5' end flanking region of one strand and another repeating dinucleotide cluster, (GT)16, in the 3' end flanking region of the same strand of this gene. In addition, the existence of two clusters of 9 continuous 5-bp repeat units, GCTTT, was found in the 3' end flanking region. The possible roles of such repeating sequence were discussed.

Comparison of control diets containing various protein levels for determining net protein utilization by rats

The objective of this study was to explore the commonly used method of Miller and Bender for determination of the net protein utilization (NPU). Eight test diets of different protein quality from both animal and vegetable sources were studied at 10% protein level with the protein content of the control diets being 0, 1, 2, 3 or 4% whole egg protein. At the end of the 10-d feeding period body nitrogen of the rat carcasses (test and control groups) was analyzed. Comparison of the body weight was also made. Rats fed either 2 or 3% egg protein maintained initial body weight and body nitrogen at the end of the feeding period. The absence of a significant difference between the NPU values of the test proteins calculated with the 1, 2, 3 or 4% egg protein group as the control and the NPU values obtained by the method of Miller and Bender (which uses the protein-free group as the control) demonstrated that the relative nutritive value for different proteins could be correctly determined by the traditional NPU method.

Monoclonal Antibodies Against the Aster Yellows Agent

Hybridoma clones secreting specific monoclonal antibodies against the aster yellows agent, a mycoplasma-like organism, were produced by using partially purified salivary gland preparations from infected leafhopper vectors as the immunogen. After 3947 hybridomas from 20 independent fusions were screened for specific antibody against the aster yellows agent, two table clones were obtained. With these monoclonal antibodies the aster yellows agent in diseased lettuce, periwinkles, and inoculative insects was specifically identified by enzyme-linked immunosorbent assay. The aster yellows agent was serologically differentiated from the mycoplasma-like organisms associated with ash yellows, loofah witches'-broom, paulownia witches'-broom, sweet potato witches'-broom, peanut rosette, maize bushy stunt, and elm phloem necrosis.

[Determination of malignancy of cartilaginous tumors (2). Determination of malignancy by nuclear DNA contents and their distribution patterns in cartilaginous tumors]

In 40 different types of cartilaginous tumors, the number of binuclear cells was calculated and DNA content was examined using fluorescent Feulgen cytophotometric technique. In 7 enchondromas and 1 synovial chondromatosis, the DNA content was diploid in 7 and hypotetraploid in 1, and showed a unimodal normal distribution. The number of binuclear cells was 0.1-0.45%, and the mean DNA content was below 4. These cases showed no evidence of disease after curettage and bone graft. The follow-up period was from 4 years 6 months to 7 years 1 month, averaging 6 years 2 months. In 2 enchondromatoses and 2 benign chondroblastomas, the DNA content was diploid and showed a unimodal normal distribution. One chondromyxoid fibroma showed a broad-unimodal tetraploid distribution, and one benign chondroblastoma showed a broad-aneuploid distribution. The nuclear DNA content was sometimes histologically similar to that of chondrosarcoma in some benign cartilaginous tumors. In 5 secondary chondrosarcomas, the DNA content was hypo- or hypertetraploid, hexaploid, and showed broad-unimodal or broad-bimodal distribution. The number of binuclear cells was from 13% to 23%. Although the size of the nucleus was small, the number of binuclear cells was evidently numerous. The preferred treatment for secondary chondrosarcoma is principally wide resection, but amputation is sometimes indicated in cases of recurrence and large tumor size. The follow-up period was from 2 years 2 months to 18 years 11 months, averaging 9 years 11 months. All 5 patients were surviving at the time of follow-up. The DNA content in chondrosarcoma was mostly hypo- or hypertetraploid, hexaploid, or octaploid and showed broad-unimodal, broad-bimodal or broad-aneuploid distribution. The number of binuclear cells was 0.55-3.5%. The mean DNA content was proportional to the number of binuclear cells, the positive correlation between the mean DNA content and the number of binuclear cells was found (p less than 1%).

Actual nitrogen deposition in mature adult rats fed moderate to high protein diets

Comparison between the positive N balance data and the actual N deposition in the same adult animals was made. In experiment 1, 24 mature 9-month old male rats were divided into three groups. One group was killed on day zero and served as the control. The two other groups were fed 25 or 49% casein diet for 8 weeks. Body weight was kept relatively constant by regulating the dietary intake. The N balance study (including body hair N loss) was conducted thrice intermittently, and body N was determined at the end of the experiment. It was found that the mean total-body N of the 49% casein groups was 967 mg higher than the 25% casein groups and 885 mg higher than the day-zero control group (P less than 0.01). The calculated N retention during the experimental period was 1876 mg for the 49% casein group. In experiment 2, a similar study was conducted except that the 25 and 49% casein diets were fed ad libitum, and body weight gain was allowed. The total-body N values of both test groups at the end of the feeding period were very close to each other, but significantly higher than that of the day-zero control group (P less than 0.01).

Protein requirements of young Chinese male adults on ordinary Chinese mixed diet and egg diet at ordinary levels of energy intake

With a total of 28 normal, healthy male adults, N balance studies with both Chinese mixed diet and egg diet were conducted at four protein levels with the former (0.45, 0.55, 0.65 and 0.75 g . kg-1 . day-1) and at three protein levels with the latter (0.35, 0.45 and 0.55 g . kg-1 . day-1) at ordinary levels of energy intake. By regression analysis, the mean maintenance N requirement (PRm) of the mixed Chinese diet calculated was 127.0 mg . kg-1 . day-1 (0.79 g protein . kg-1 . day-1). Estimate a allowance for individual variation to cover the 97.5% population (PR0.975) was 188.1 mg . kg-1 . day-1 (1.18 g protein . kg-1 . day-1). As for the egg diet series, PRm and PR0.975 were 98.2 mg N . kg-1 . day-1 (0.61 g protein . kg-1 . day-1) and 141.6 mg N . kg-1 . day-1 (0.89 g protein . kg-1 . day-1), respectively. Net protein utilization (NPU) of egg diet protein was significantly higher than that of the Chinese mixed diet protein (P less than 0.01), with mean values of 56 versus 43. True digestibility of the mixed diet and egg diet proteins was 96.5 and 98%, respectively. The efficiency of utilization of the Chinese mixed diet protein was 73-77% of the egg protein, based on relative N requirements.

Protein requirements of normal infants at the age of about 1 year: maintenance nitrogen requirements and obligatory nitrogen losses

With 34 normal, healthy male infants aged 9-17 months, a total of 61 nitrogen (N) balance studies was conducted with N intake between 12 and 180 mg/kg/day. By regression analysis, the crude N maintenance requirements, either with whole egg or cow's milk protein, were estimated to be about the same, 106 and 103 mg/kg/day, respectively. The 97.5% confidence limits for the requirements were 128 (egg) and 142 (milk) mg/kg, respectively. Sums of the obligatory urinary and fecal N for the egg and milk protein series were 75 and 71 mg/kg as compared with 76 mg/kg of actually measured figure. Ratio of the maintenance N requirement to the obligatory N loss was 1.4. In another 15 N balance study, for which N intake from milk formulae ranged between 220 and 320 mg/kg/day, the mean apparent N retention was 25% of the intake. Total integumental N losses (skin + hair + nail) of infants fed 217-522 mg N/kg/day amounted to 7.8 +/- 2.9 mg/kg daily. Egg protein had somewhat higher digestibility than cow's milk protein, 92 versus 87%, but has lower biological value, 76 versus 82. Net protein utilization (NPU) estimated from the regression line was about the same for both proteins, 71 and 69, respectively.