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Biomedical subjects

J Versteeg

Publications and source records attributed to J Versteeg.

16 recordsLinked to original sources
PubMed1990

Tissue-localizing properties of some photosensitizers studied by in vivo fluorescence imaging.

Using fluorescence imaging, the tissue-localizing properties of five photosensitizers were studied in vivo in tumours in 'sandwich' observation chambers and in tumours growing on thigh muscle. The preliminary results indicate that of the three photodynamically active dyes tested (haematoporphyrin derivative, Photofrin II and aluminium phthalocyanine tetrasulphonate), the phthalocyanine possesses the best tumour-localizing properties. This makes it possible to combine tumour fluorescence detection and photodynamic therapy with reduced skin photosensitivity. The two photodynamically inactive dyes tested (uroporphyrin I and acridine red) may be useful for application in fluorescence imaging to localize superficial tumours without inducing skin photosensitivity. In particular, acridine red has remarkable tumour-localizing properties, but is rather toxic.

Animals↗
PubMed1990

Wavelength dependence of hematoporphyrin derivative photodynamic treatment effects on rat ears.

The in vivo wavelength dependence of hematoporphyrin derivative (HpD) photodynamic treatment (PDT) has been studied. Ears of 136 rats were treated at six red and four blue-green laser wavelengths (615-635, 488-514.5 nm). Hematoporphyrin derivative was administered intraperitoneally (15 mg/kg) and 24 h later both ears were irradiated, at different wavelengths, for t = 6.5, 10 or 15 min at 60 mW/cm2. Four parameters (thickness, average erythema, eschar and loss of tissue) were quantified and a combined score (CS) of effects was established statistically. The maximum combined score during follow-up was taken as a measure for the biological effect. The light distribution in rat ears during irradiation with red and blue-green light was estimated from in vivo measurements and the transport theory. Statistical analysis of the combined score data yielded values for the relative biological effectiveness (RBE). Relative biological effectiveness maxima occurred at 501.7 and 625 nm. Analyzing erythema and loss of tissue separately yielded maxima at the same wavelengths. Quantitative agreement between the latter two sets of relative biological effectiveness values was obtained only when they were referred to the actual light energy fluence in tissue, rather than to the incident fluence. These relative biological effectiveness values are about 2.3 at 501.7 nm and 1.35 at 625 nm, taking relative biological effectiveness = 1 at 630 nm.

Animals↗
PubMed1989

Fetal pathology in human parvovirus B19 infection.

In a current Netherlands study on the effects on mother and child of infection with the human parvovirus B19 during pregnancy, 10 pregnancies have been reported. Three of them ended before term: two in fetal death and one by elective abortion. In two of these fetuses B19 infection in cells other than those of the erythroid series was demonstrated, and in the one terminated, ocular malformation and extensive inflammatory reactions in all fetal and placental tissues were found. The presence of B19 DNA was demonstrated by dot hybridization in placental and fetal tissues. In the third no gross fetal abnormalities were found, although B19 DNA was detected in several fetal tissues by in-situ hybridization. Of the remaining seven pregnancies, six ended at term in the birth of apparently healthy babies. The other child was born near term with a low birthweight and multiple congenital malformations, but with no proof of intrauterine B19 infection. It is concluded that B19 infection in pregnancy can interfere with organ development and may lead to intrauterine fetal death.

Abortion, Induced↗
PubMed1989

Effect of etching glass-ionomer cements on bond strength to composite resin.

The use of glass-ionomer cement in restorative dentistry has seen a revival because of its capacity for being etched and bonded to composite resin. Past investigators compared an etched cement surface with an unetched surface that was set against a smooth surface. Clinically, however, a glassy smooth surface is not produced when the cement is used as a base. Using Scotchbond bonding resin, we developed this two-part study to evaluate the tensile bond strengths of P-30TM composite resin to several glass-ionomer cements that were (a) unetched but allowed to set in air and (b) etched for 30 s with orthophosphoric acid, and to compare them with the cohesive strength of the respective cement. Using a silver nitrate staining technique, we also evaluated the microleakage of class V cavities restored with SiluxTM composite resin under a base of etched or unetched Ketac Bond cement. Although there were significant differences among three cements between their cohesive strength and the resin bond strength after the two surface treatments (p less than 0.01), the bond to the unetched surface was generally similar to that of the etched surface of the cement. The remaining groups showed no statistical difference. The microleakage was similar in the two groups. SEM micrographs showed a rough topography of the unetched cement that resembled that of the etched surface. This in vitro study suggests that acid-etching a glass-ionomer base for resin-bonding may not be necessary for specific materials. Further clinical evaluation is recommended to validate this observation intra-orally.

Acid Etching, Dental↗
PubMed1979

Nervous system complications of herpes zoster: immunofluorescent demonstration of varicella-zoster antigen in CSF cells.

In nine out of 11 patients with herpes zoster and neurological symptoms varicella-zoster antigen was demonstrated in CSF cells by indirect immunofluorescent staining. Cerebrospinal fluid cytology was in most cases highly suggestive of viral infection. This study demonstrates the value of both immunofluorescent staining on CSF cells and CSF cytology, as corroboration of an otherwise exclusively serologically based virological diagnosis.

Adolescent↗
PubMed1979

ECHO 25 focal encephalitis and subacute hemichorea.

ECHO virus 25 focal encephalitis was documented for the first time in a 5-year-old boy with unequivocal hemichorea. Hemichorea caused by enterovirus CNS disease has never been reported. ECHO virus antigen in cerebrospinal fluid (CSF) cells was demonstrated by the indirect immunofluorescent technique and typed by a significant rise in neutralizing antibodies against ECHO virus 25. Sequential computerized tomographic (CT) studies with digital analysis demonstrated the evolution of a focal process in the head of the left caudate nucleus, ultimately leading to replacement of tissue by a CSF-containing cyst. In the unclarified pathogenesis of cerebral disease in enterovirus infection, this case suggests a focal inflammatory process rather than vasculitis, occlusion, and infarction. Finally, the near-complete recovery of our patient demonstrated that the mere loss of neostriatal tissue was not decisive in itself, because the tissue loss was permanent and the symptoms were transient.

Antibodies, Viral↗
PubMed1978

Varicella and acute cerebellar ataxia.

In two cases of varicella-associated cerebellar ataxia, varicella-zoster antigens in CSF cells were shown by an indirect immunofluorescent technique. Direct viral invasion in CNS disease complicating varicella plays an important part in pathogenesis and rules out a single immune-mediated mechanism.

Antigens, Viral↗
PubMed1978

Viral meningoencephalitis and head injury.

Among 162 children referred with head injury (in a 3-year period) a viral meningoencephalitis was proven to be present in seven cases. Only one patient showed symptoms of infection before the accident. On admission classical signs of viral meningoencephalitis were absent or mixed with the complications of head injury. A diagnosis of viral meningitis/meningoencephalitis was documented by immunofluorescent demonstration of viral antigens in CSF cells and/or pattern of CSF cytology and/or conventional serological methods. Whether the trauma and the infection are coincidental or causally related can not be decided definitively. A hypothesis is presented suggesting diminished alertness in subclinical viral meningoencephalitis, leading to accident proneness.

Antigens, Viral↗
PubMed1975

A local outbreak of paralytic rabies in Surinam children.

A rapidly fatal encephalomyelitis, which was in most cases characterized by ascending paralysis, developed in seven children of the age of 3 to 10 years in a bushnegro village in the interior of Surinam. Rabies virus was recovered from the central nervous system of three autopsied children. Although the source of infection has not been detected, there is an indication that, at least in some cases, the disease has been transmitted by rat-bite rather than by vampire bats. During the same period a few cases of minor febrile illness occurred in the same community. Since virological and serological evidence of a wide-spread distribution of Coxsackie A virus type 4 was obtained, the latter illness may presumably be attributed to this virus.

Animals↗
PubMedDate not supplied

Is aciclovir prophylaxis necessary after bone marrow transplantation?

To assess the cost-effect relationship of aciclovir prophylaxis versus early treatment, we performed a retrospective study in 44 allogeneic bone marrow transplant recipients, who had only received aciclovir for therapeutic purposes. After bone marrow transplantation 18 herpes simplex infections occurred in 15 of the 33 patients who were seropositive for herpes simplex virus. In ten patients without clinical signs, routine viral cultures yielded herpes simplex virus. Aciclovir was given intravenously to the patients with mucocutaneous herpes infection. All infections responded rapidly. It can be calculated that restricting the drug to therapeutic use reduced the amount of aciclovir used, which in turn diminished the cost of treatment and the risk of aciclovir resistance.

Acyclovir↗
PubMedDate not supplied

The anterior eye segment in virus induced primary congenital aphakia.

Nine aphakic eyes from human embryos infected with Rubella or Parvovirus B19 during early pregnancy were histologically examined. One of the eyes conformed with the classical description of primary congenital aphakia (PCA), namely, that no structures of the anterior eye segment are present. However, the other eight eyes did reveal such structures. In these eyes embryological development and differentiation of the anterior eye segment had taken place, despite the fact that no lens had formed previously. On the basis of this study it is concluded that PCA is not necessarily associated with aplasia of the anterior eye segment.

Anterior Eye Segment↗