Three-dimensional structure of human retinal vessels studied by vascular casting

A new casting technique for studying the three-dimensional structure of the human retinal vascular system on post mortem tissue was developed. The technique was designed to provide an overview presentation of the retinal vasculature such that localized areas with vascular pathology could be identified for further analysis of three-dimensional structure. The paper presents qualitative characteristics of three-dimensional structure in the normal human retinal vascular bed, to provide a basis for future studies on vascular impairment in retinal disease.

Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS

A ring chromosome 20 in a male infant with epileptic seizures, mental and somatic growth retardation, and behavioural disturbances is described. Conventional cytogenetics revealed the karyotype to be 46,XY,r(20)(pter-->qter) and no signs of mosaicism were found. Fluorescence in situ hybridisation using the clone p20Z1 identified the ring to be derived from chromosome 20. By counting 111 metaphases, only 7% were found to be missing the ring. The absence of telomeric sequences in the ring chromosome was demonstrated by multicolour PRINS: a three-step PRimed IN Situ labelling technique, using unlabelled primers. A terminal deletion of both arms thus seems to be the cause of the ring formation in the proband. Bivariate flow-analysis of chromosomes verified a deletion of the ring chromosome. The clinical and cytogenetic findings are compared with previous cases. A specific ring 20 syndrome seems justified.

Lateral growth and terminal differentiation during repeated epidermal regeneration in vitro

By incubating multilayered primary cultures of human epidermal keratinocytes in a low calcium medium, the suprabasal layers can be stripped off leaving a basal cell monolayer. When this monolayer is refed normal calcium medium a reproducible series of cell kinetic, morphological and biochemical changes take place resulting in the regeneration of a multilayered tissue. The stripping procedure seems to induce the selective proliferation of a cohort of basal cells that is committed to vertical migration and rapid terminal differentiation. In contrast, when the basal cells are allowed to regenerate in the presence of the strong mitogen, cholera toxin, lateral growth and continued proliferation are favoured at the expense of the capacity of the cells to differentiate. Repeated stripping of the same cultures disclosed a considerable heterogeneity in the capacity of the basal cells to regenerate the suprabasal layers. The number of times the basal cells could restore the suprabasal layers after repeated stripping varied from four to nine times. A negative correlation between donor age and regenerative capacity was observed. The experiments with repeated stripping of the same cultures also showed that the capacity to proliferate and to restore the multilayering was fully retained for at least four cycles of stripping-regeneration, whereas the capacity to terminally differentiate was rapidly lost. It is suggested that the present system of regenerating epidermal tissue cultures may serve as an experimental model for the study of epidermal tissue homeostasis and cellular aging.

Two novel nonradioactive polymerase chain reaction-based assays of dried blood spots, genomic DNA, or whole cells for fast, reliable detection of Z and S mutations in the alpha 1-antitrypsin gene

Two new nonradioactive polymerase chain reaction (PCR)-based assays for the Z and S mutations in the alpha 1-antitrypsin gene are presented. The assays take advantage of PCR-mediated mutagenesis, creating new diagnostic restriction enzyme sites for unambiguous discrimination between test samples from individuals who are normal, heterozygous, or homozygous for the mutations. We show that the two assays can be performed with purified genomic DNA as well as with boiled blood spots. The new assays were validated by parallel testing with a technique in which PCR is combined with allele-specific oligonucleotide (ASO) probes. In all cases tested the results obtained by the different techniques were in accordance. The new assays can be used for prenatal diagnostics and can be performed directly with boiled tissue samples. Because the new assays are easy to perform and reliable, we conclude that they are well suited for routine diagnosis.

Two Novel Nonradioactive Polymerase Chain Reaction-Based Assays of Dried Blood Spots, Genomic DNA, or Whole Cells for Fast, Reliable Detection of Z and S Mutations in the α1-Antitrypsin Gene

Two new nonradioactive polymerase chain reaction (PCR)-based assays for the Z and S mutations in the alpha 1-antitrypsin gene are presented. The assays take advantage of PCR-mediated mutagenesis, creating new diagnostic restriction enzyme sites for unambiguous discrimination between test samples from individuals who are normal, heterozygous, or homozygous for the mutations. We show that the two assays can be performed with purified genomic DNA as well as with boiled blood spots. The new assays were validated by parallel testing with a technique in which PCR is combined with allele-specific oligonucleotide (ASO) probes. In all cases tested the results obtained by the different techniques were in accordance. The new assays can be used for prenatal diagnostics and can be performed directly with boiled tissue samples. Because the new assays are easy to perform and reliable, we conclude that they are well suited for routine diagnosis.

Absence of interaction between oxcarbazepine and erythromycin

When erythromycin (ERY) is co-administrated with the antiepileptic carbamazepine (CBZ), a drug interaction may cause an increase in CBZ plasma concentrations, which can result in CBZ related toxic symptoms. This cross-over study was designated to investigate whether ERY influences the pharmacokinetics of the new antiepileptic oxcarbazepine (OXC) and its metabolites. In 8 healthy volunteers there were no significant differences in AUC, peak plasma concentrations or time to peak concentration when OXC was administered either with or without ERY. The results of this study suggest that OXC may offer an important advantage over CBZ especially when concomitant therapy with ERY is required.

Insulin-like growth factor I in initial renal hypertrophy in potassium-depleted rats

We investigated insulin-like growth factor I (IGF-I) in the kidney during the initial renal enlargement induced by dietary K depletion in rats. Kidney weight increase was significant after 3 days of K depletion and amounted to 29% after 7 days compared with pair-fed controls [839 +/- 34 vs. 648 +/- 17 mg (SE), P less than 0.01]. The kidney growth occurred despite almost complete arrest in body weight gain in K-depleted animals (8 +/- 3 vs. 34 +/- 4 g/7 days in controls, P less than 0.01). Whole kidney protein, RNA, and DNA estimations indicated that cellular hypertrophy during the first 4 days was followed by hyperplasia. Immunoassayable kidney IGF-I concentration increased by 106% (673 +/- 30 vs. 327 +/- 14 ng/g, P less than 0.01) in K-depleted animals 24 h after induction of K depletion, stayed elevated until day 4, and returned to control levels on day 7. After K depletion for 24 h, IGF-I immunostaining was markedly increased in the medullary parts of the collecting ducts from K-depleted animals, whereas kidney IGF-I gene expression (IGF-I mRNA) had decreased by 36%. The increase in total kidney IGF-I concentration and immunostainable IGF-I in collecting ducts in kidneys from K-depleted rats precedes the renal hypertrophy and thereby suggests a renotropic role for IGF-I. The increase in kidney IGF-I concentration is not associated with increased IGF-I mRNA levels, indicating that non-transcriptional mechanisms may be responsible for the renal IGF-I accumulation.

Effects of dextropropoxyphene on the steady-state kinetics of oxcarbazepine and its metabolites

The effects of dextropropoxyphene on the steady-state kinetics of oxcarbazepine and its metabolites were investigated in eight patients with epilepsy or trigeminal neuralgia. One patient dropped out of the study, presumably due to side-effects of dextropropoxyphene. Dextropropoxyphene did not affect the plasma levels of the principal active metabolite, 10,11-dihydro-10-hydroxy-carbamazepine. Since dextropropoxyphene is known to increase the plasma levels of carbamazepine, leading to toxicity, the findings of this study suggest that oxcarbazepine is a useful alternative to carbamazepine when concomitant dextropropoxyphene therapy is required.

The influence of age on the pharmacokinetics of the antiepileptic agent oxcarbazepine

The disposition of oxcarbazepine was studied in 12 young and 12 elderly healthy male and 12 young and 12 elderly healthy female volunteers, with emphasis on the influence of age. Oxcarbazepine was administered as a single dose of either 300 mg (men) or 600 mg (women), followed by multiple-dose (300 mg) administration twice a day for 7 days (men) or 6 days (women). Semilogarithmic plasma concentration-time curves showed an increasing decline at decreasing concentrations. Accumulation of the pharmacologically active metabolite monohydroxycarbamazepine was found to be more than one would anticipate on the basis of linear and unchanged pharmacokinetics. Saturation did not seem to occur at the level of renal excretion. No apparent differences between male and female volunteers were observed. A significant higher maximum concentration, higher area under the curve parameters, and a lower elimination rate constant were observed in the elderly. These observations are in line with a smaller renal clearance of monohydroxycarbamazepine in the elderly group. In a clinical situation, these age-related differences are not likely to have important implications. In general, treatment with oxcarbazepine was well tolerated.

Quantitative determination of IL-1 alpha-induced IL-8 mRNA levels in cultured human keratinocytes, dermal fibroblasts, endothelial cells, and monocytes

The presence of the leukocyte chemotactic cytokine interleukin 8 (IL-8) in psoriatic scales and in epidermal tissue overlying allergic patch test reactions suggests a role for this cytokine in certain inflammatory skin diseases. IL-8 can be produced by several cell types present in the skin. Their relative potentials for IL-8 expression has, however, not yet been studied, due to the lack of convenient methods for quantitative comparison of specific mRNA amounts in different cell types. Using a new method for quantification, we compared specific IL-8 mRNA amounts in cultures of keratinocytes, dermal fibroblasts, endothelial cells, and monocytes, stimulated with interleukin 1 alpha (IL-1 alpha). Endothelial cells produced very high, fibroblasts and monocytes intermediate, and keratinocytes low amounts of IL-8 mRNA. We also studied the time course of IL-8 mRNA levels in the four cell types following IL-1 alpha stimulation, and found a clear difference both in onset and stability of the response. We discuss the different strength of the response at different time points in the cell types analyzed in relation to their possible role in regulation of the normal response to stimulation.

Morphological differentiation and changes in polypeptide synthesis pattern during regeneration of human epidermal tissue developed in vitro

By incubating multilayered primary cultures of human keratinocytes in low-calcium medium the suprabasal cell layers can be stripped off leaving a basal cell monolayer. When this monolayer is re-fed normal calcium medium a reproducible series of cell kinetic, morphological, and biochemical changes takes place resulting in the reestablishment of a multilayered tissue. Analysis of cell-cycle-specific proteins indicated that, during regeneration, a large cohort of cells became synchronized undergoing DNA replication after 3 days. Examination of culture morphology at the ultrastructural level confirmed the capacity of the basal cell monolayer to gradually reestablish a multilayered, differentiated epithelium. The ultrastructural appearance at 7 days poststripping was similar to that of unstripped cultures and was indicative of a tissue in steady state. Quantitation of cornified envelope formation at different times during regeneration showed that an increasing proportion of the cells were able to undergo terminal differentiation. In general, the pattern of keratin synthesis in the original epidermal explant labelled in vitro was similar to the pattern observed in human epidermis in vivo; however, in contrast to epidermis in vivo the explant also synthesized the hyperproliferative keratins 6 and 16. The in vitro differentiated keratinocytes showed underexpression of several proteins identified as differentiation markers, whereas several basal cell markers were overexpressed compared to the original explant. In addition, the in vitro differentiated keratinocytes synthesized some new proteins, notably keratins 7, 15 and 19. The basal layer remaining after stripping mainly expressed basal cell markers; however, during recovery, some of the differentiation-specific markers (e.g. keratin 10 and 15) were again expressed together with keratin no. 19, which is also expressed during wound healing in vivo. It is suggested that the present system of regenerating epidermal tissue cultures may serve as an experimental model to investigate certain aspects of the regulation of epidermal tissue homeostasis.

Ultrasonographic, three-dimensional scanning for determination of intraocular tumor volume

Important prognostic information may be gained from knowing the volume of intraocular tumors, such as choroidal melanomas. To measure such volume, we developed an ultrasonographic 3-D scanning system, which operates by an axial, back and forth, half-turn rotation of a commercial sector scanning transducer, applied directly onto a closed eyelid. Control of movement, data acquisition, and image analysis are accomplished by means of a microcomputer and application-specific software. The elapsed time for scanning and digitizing 11 cross-sectional images across a human eyeball, is 4 sec. Outlines of specific structures are traced manually. The system was tested through repeated, in vitro measurements of known volumes of meat; the mean variation coefficient of these measurements was 2.8%. While accurate estimates were obtained on volumes between 0.01-0.25 ml, these are linearly dependent on gain setting. A patient with a choroidal melanoma was scanned repetitively. The procedures of scanning and tracing contributed about equally to the total variance. This method of scanning allows repeatable, reliable, and easily generated measurements of a tumor's volume and, thus, has great potential for use in the diagnosis and treatment of malignant, intraocular tumors.

Application of fluorescence in situ hybridization techniques in clinical genetics: use of two alphoid repeat probes detecting the centromeres of chromosomes 13 and 21 or chromosomes 14 and 22, respectively

Two cloned DNA fragments, one derived from an alpha satellite subfamily common to chromosomes 13 and 21, and the other derived from a similar subfamily common to chromosomes 14 and 22, have been used as biotinylated probes in in situ hybridization studies. Under high stringency conditions, chromosome specific centromeric labelling can be obtained. The applications of this technique in clinical situations are illustrated on metaphases from a fetus with trisomy 21, a fetus with trisomy 13, and a child with clinical features of cat-eye syndrome.

Effects of extra- and intracellular calcium concentration on DNA replication, lateral growth, and differentiation of human epidermal cells in culture

Variation in the extra- and intra-cellular concentration of calcium ([Ca]e and [Ca]i) affected the 3H-thymidine labeling pattern of sorted S-phase cells in human epidermal cultures. A lowering of [Ca]e resulted in retarded lateral growth but, unless [Ca]e was extremely low, caused an increase in the proportion of strongly labelled (rapidly cycling) S-phase cells. An increased desquamation of superficial cells due to a reduced cellular cohesiveness was also observed in low calcium medium. Thus, a lowering of [Ca]e might stimulate the proliferation of a pool of cycling cells destined for rapid terminal differentiation and tissue regeneration, whereas proliferation destined for lateral growth is inhibited. Attempts to decrease the [Ca]i with the calcium chelator quin-2 at low [Ca]e seemed to elevate the proportion of strongly labelled S-phase cells, whereas an increased [Ca]i obtained with the ionophore A23187 caused a dramatic decrease in the proportion of S-phase cells that showed strong 3H-thymidine incorporation. This implies that variation in both [Ca]i and [Ca]e may play a role in the regulation of proliferation and differentiation, in keratinocytes.

Synthetic epidermal pentapeptide and related growth regulatory peptides inhibit proliferation and enhance differentiation in primary and regenerating cultures of human epidermal keratinocytes

A pentapeptide that inhibits proliferation of mouse epidermal keratinocytes in vivo and in vitro has been purified from mouse skin extracts. In the present study the effect of a synthetic analog of the epidermal pentapeptide on proliferation and differentiation of cultured human epidermal keratinocytes was investigated. In young, rapidly growing primary cultures the pentapeptide caused a dramatic decrease in mitotic activity and also induced pronounced changes in the balance between kinetically defined subpopulations of proliferating cells. A dipeptide derived from the pentapeptide was found to be at least as potent. A serine derivative of a hemoregulatory peptide also seemed to be active. When tested in epidermal cultures regenerating after removal of the suprabasal cell layers, both the pentapeptide and the dipeptide were shown to cause a delay in the proliferative response. Both peptides were also able to stimulate early (increase in cell size) and late (cornified envelope formation) events in the differentiation pathway of the keratinocyte. The apparent stimulatory effect on differentiation was most clearly seen in regenerating cultures, whereas the effect on primary cultures varied with the experimental set-up. It is suggested that homologous epidermal peptide(s) may play a major role in the regulation of human epidermal homeostasis.

Pharmacokinetic comparison of two carbamazepine slow-release formulations

In a single-blind pharmacokinetic study patients being treated with conventional carbamazepine (CBZ) in a t.i.d. regimen were randomly allocated to identical doses of two CBZ slow-release formulations (Trimonil Retard and Tegretol Retard) administered once daily. Statistical analysis involved the following parameters: AUC, Cmin, Cmax and Fluctuation Index (FI). With regard to Cmin and FI statistically significant differences in favour of Tegretol Retard were observed.

High-frequency transfection of cultured human epidermal basal cells that differentiate to form a multilayered tissue

Primary cultures of human keratinocytes form a multilayered tissue. By incubating the tissue cultures in Ca2(+)-free medium the differentiated cell layers can be stripped off leaving a basal cell monolayer. We have developed a method for high-frequency transfection of these epidermal basal cells with genes inserted into Epstein-Barr virus-based expression vectors. Using the Escherichia coli lac z gene as a marker gene, the transient and long-term expression and the fate of the transfected cells were studied. During regeneration of the multilayered tissue most of the transfected basal cells enlarge and undergo differentiation, but a minor population remains as basal cells. Incubation with the tumor promotor 12-O-tetradecanoylphorbol-13-acetate results in an increase in the proportion of transfected keratinocytes that are small, suggesting a relative expansion of the immature cell pool.

[Transabdominal chorion villus biopsy following abnormal ultrasonic findings in the second trimester]

If oligohydramnios, growth retardation or foetal malformations are demonstrated by ultrasonic scanning in the second or third trimesters, this implies that the risk of chromosome anomalies is significantly increased. In cases such as these, determination of the foetal karyotype may therefore be indicated. Until recently, amniocentesis has been employed for this but the results of the chromosome investigation are not available until two to three weeks after the intervention. The delay between amniocentesis and the result of chromosome investigation imposes a mental strain on the pregnant woman. Three patients with abnormal ultrasonic findings in the second trimester were, therefore, submitted to transabdominal chorion villus biopsy and, in all three cases, a karyotype was available within 48 hours. Chorion villus biopsy in the second (and third) trimester is indicated in pregnancies in which oligohydramnios, growth retardation or foetal malformations have been demonstrated by ultrasonic scanning, in cases where referral for antenatal diagnosis is very late and when chromosome investigation after amniocentesis proves unsuccessful and repeated amniocentesis would result in an unacceptably late result.

The incidence of herniated disc and varicella zoster virus infection in lumboradicular syndrome

121 patients suffering from lumboradicular syndrome were examined for the presence of varicella zoster virus (VZV) infection. Lumbar myelography was carried out on all. VZV-antibody determination in blood, as well as in spinal fluid, was by indirect ELISA. In 40% of cases lumbar myelography revealed no signs of a herniated disc; none had raised antibody titre in spinal fluid. VZV-antibody titre in blood indicated VZV infection in only 3.

[Molecular biology of keratins and their significance in the clinical diagnosis of tumors]

Keratins are the most heterogenic class of intermediary filament molecules and form tonofilaments in all types of epithelial cells. At least 19 different human keratins have been demonstrated. On the basis of biochemical and immunological criteria, these may be subdivided into two subtypes (type I and type II). Recent molecular biological investigations have provided considerable insight into the construction of the keratin molecule and the tonofilament structure and the corresponding gene structure. The basic structure in the tonofilament is a dimer composed of one type I and one type II molecule which is the background for the coordinated paired expression of type I and type II keratins which are observed in all epithelial cells. A given epithelial cell type expresses a constant pattern of keratin pairs which serve as markers for the cell type concerned. In general, the characteristic keratin pattern is retained in neoplastic differentiation of the epithelial cell. With the production of monospecific antikeratin antibodies, it is now possible to identify carcinomata immunologically which improves the possibilities of determine the degree of differentiation and the source. Employment of antikeratin antibodies in tumour diagnosis may be anticipated to be of significance for assessment of the prognosis and monitoring and choice of therapy.

Retroperitoneal varicose veins simulating lymph nodes

A case of retroperitoneal varicose veins simulating neoplastic masses in a patient with unknown portal hypertension is presented. The radiological modalities of choice in differential diagnosis are briefly discussed. The use of contrast-enhanced computed tomography is recommended.

Low Ca2+ stripping of differentiating cell layers in human epidermal cultures: an in vitro model of epidermal regeneration

An in vitro model of the epidermal regeneration process is described. Incubation of multilayered, keratinizing cultures of human epidermal cells in Ca2+-free medium for 72 h results in a complete stripping of all suprabasal layers. When the Ca2+ stripped cultures are refed normal Ca2+ medium a reproducible series of morphologic and cell kinetic changes takes place. It is suggested that these changes represent a general pattern of regeneration after epidermal wounding. After an initial lag phase the regenerative response is principally effected by a recruitment to the proliferating pool of cells with a high rate of DNA synthesis. The cells seem to be programmed to rapid differentiation. Studies with cholera toxin suggest that this adenylate cyclase-stimulating agent is able to induce significant changes in the regenerative process causing a prolonged, but less intense, proliferative response leading to lateral growth rather than to rapid differentiation.