Chemotherapy extravasation injuries beyond the immediate stage: A series of 15 cases treated according to a preset surgical algorithm based on time of presentation.

Chemotherapy extravasation can cause severe harm. There is a lack of evidence-based standardization on the surgical management of such injuries beyond the immediate stage. In an algorithm connecting presentation time post-injury with surgical treatment could help standardize future treatment. This study prospectively validated a preset standardized surgical algorithm based on presentation time in a consecutive series between October 2017 and October 2020. Chemotherapeutic agent, site and extent of injury, type of surgery and outcome at a minimum of 6 months' follow-up were collected. Seven thousand six hundred twelve individuals received chemotherapy during that period; 15 patients suffered extravasation injuries, 2 of whom were referred from outside our hospital. This algorithm distinguished: A) beyond the immediate stage and up to 2 days, treated with saline subcutaneous washout (SCWO) and vacuum-assisted closure (VAC) dressing; B) 2 to 5 days, open surgical decompression and VAC dressing; C) 5 to 10 days, non-operative management with surveillance; and D) more than 10 days, radical necrotic excision with or without VAC dressing and tissue reconstruction. In 2 patients in Group A and 3 patients in Group B, all vesicant symptoms resolved. Five of the 6 patients in Group C (3 vesicant, 3 non-vesicant) did not progress into necrosis or infection, and 1 case of vesicant extravasation progressed to a localized ulcer beyond this period and, as surgery was refused, led to a chronic ulcer with stiffness; 2 cases of non-vesicant extravasation developed a recall phenomenon but resolved after the third cycle. Of the 4 patients in Group D, all vesicant, 2 were treated with no complications, 1 had complex regional pain syndrome (CRPS) due to late presentation, and 1, referred with necrotizing fasciitis, underwent above-elbow amputation but died due to septic shock. This study demonstrated a uniform surgical approach in a series of 15 cases; larger studies are still needed to validate the efficacy of this protocol in reducing morbidity. LEVEL OF EVIDENCE: IV.

Specific inhibition of the rat ligand-gated ion channel P2X3 function via methoxyethoxy-modified phosphorothioated antisense oligonucleotides.

P2X3 is one receptor of a family of seven ligand-gated ion channels responding to purines. Increasing evidence indicates its involvement in neuronal signaling and in pain. However, there is currently no selective inhibitor known for this subtype. In order to obtain such a specific inhibitor, a variety of antisense oligonucleotides (ASO) against rat P2X3 was tested, and dose-dependent, sequence-specific downregulation of the rat P2X3 receptor (expressed in a Chinese hamster ovary cell line [CHO-K1]) on the mRNA, protein, and functional levels was observed. Using real-time quantitative PCR, a dose-dependent downregulation of P2X3 mRNA by ASO, as compared with untreated and mismatch controls, was demonstrated. Subsequently, downregulation by the two most potent ASO was confirmed at the protein level by Western blot. Sequence specificity was shown by titration of mismatches to the original selected oligonucleotide, and this correlated with progressive loss of P2X3 inhibition. The functional response of the P2X3 receptor was examined using whole-cell voltage clamping. Upon application of 10 microM of a nonspecific agonist, alpha,beta-methylene-ATP (alphabeta meATP), pretreatment with increasing amounts of the most active ASO 5037 correlated with a decrease in depolarization. The ability to specifically downregulate the P2X3 receptor by ASO treatment will allow investigation of the biologic role of this receptor in neuronal tissues and eventually in in vivo models of chronic pain.

Differential distribution of rat PDE-7 mRNA in embryonic and adult rat brain.

Currently not much is known about the distribution and function of the phosphodiesterase type 7 (PDE-7) enzyme. Therefore, we carried out an extensive distribution analysis of the rat and human PDE-7 by in situ hybridization as well as RT-PCR. We isolated a partial rat cDNA clone that is highly homologous to the sequence of the human PDE-7 gene. RT-PCR tissue distribution analyses revealed expression of the mRNA of the human and rat-enzymes in most of the examined tissues, like adult heart, lung, brain, and liver, as well as in several cell lines of the immune system. In situ hybridization with the rat PDE-7 showed a differential expression pattern during the late phases of the developing rat brain with higher levels of mRNA in cortical and telencephalic structures in d 16, 18, and 20 embryonic stages, whereas in adult rat brain, higher amounts of mRNA could only be detected in cerebellum and, to a lesser extent, in hippocampus and the olfactory system.

Distribution of 5-HT4 receptor mRNA in the rat brain.

We have analyzed the brain distribution of the rat 5-HT4 receptor mRNA. A receptor specific probe was used for in situ hybridization of rat brain sections. Abundant expression of the 5-HT4 receptor mRNA was observed in the olfactory system, striatum, medial habenula and the hippocampal formation, while faint or no specific signals could be detected in most other areas of the brain. Several brain areas which display strong ligand binding do not contain mRNA, suggesting an axonal localization of the 5-HT4 receptor.

Inhibitors of type IV phosphodiesterases reduce the toxicity of MPTP in substantia nigra neurons in vivo.

The neuropathology of Parkinson's disease is characterized by the degeneration of dopaminergic neurons in the substantia nigra. We have recently shown that the activation of protein kinase A improves the survival of dopaminergic neurons in culture and, furthermore, protects them from the dopaminergic neurotoxin, 1-methyl-4-phenylpyridinium ion (MPP+) in vitro. We have now analysed the potential of phosphodiesterase inhibitors to increase cAMP levels in dopaminergic neurons, to improve their survival in culture and to protect them from the toxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in vivo. Increasing intracellular cAMP with phosphodiesterase type IV-specific inhibitors enhanced the survival of dopaminergic neurons in culture. Inhibitors of other phosphodiesterase types were not active. In vivo, phosphodiesterase type IV inhibitors reduced the MPTP-induced dopamine depletion in the striatum of C57BL/6 mice. Furthermore, the loss of tyrosine hydroxylase-immunopositive neurons in the substantia nigra of these animals was diminished. After Nissl staining, a similar reduction of the MPTP-induced loss of neurons was observed in the substantia nigra. The protective effect of protein kinase A activation did not appear to be due to the blocking of MPP+ uptake into dopaminergic neurons. This was not decreased after treatment with forskolin or 8-(4-chlorophenylthio)-cAMP. Thus, protein kinase A regulates the survival and differentiation of dopaminergic substantia nigra neurons in vivo, implicating a therapeutic potential for substances which regulate cAMP turnover in these neurons.

Brain distribution of four rat homologues of the Drosophila dunce cAMP phosphodiesterase.

We have analyzed the brain distribution of the rat cAMP-specific phosphodiesterases (rPDEIV) which are closely related to the defective gene products of the drosophila melanogaster learning and memory mutant dunce. PCR analysis of rat brain cDNA was performed on the four known dunce-like cAMP PDE rat isogenes (rPDE-IV-A, -B, -C, -D). High expression of three of these isogenes (rPDEIV-A, -B, -D) highlighted their involvement in regulation of cAMP in the brain. Specific probes for all four isogenes were then used for in situ hybridization of rat brain sections. Distinct but overlapping expression patterns were observed for rPDEIV-A, rPDEIV-B, and rPDEIV-D. Abundant expression of these subtypes was observed in the olfactory system, the hippocampus and the cerebellum, while no specific signals could be detected in most areas of the brain for the subtype rPDEIV-C.

The toxic pathophysiology of retinol hypervitaminosis and norethisterone enantate in rats.

The use of the long acting contraceptive was accompanied by clinically overt toxic manifestations on the liver, glucose tolerance, in addition to the danger of carcinogenicity. Also chronic hypervitaminosis "A" leads to a variety of toxic manifestations of obscure mechanism. The objective of this experimental work was directed to study the toxicity of the isolated and combined augmented doses of the two therapeutic agents on the female albino rat. The results of the present study evidenced that the long acting contraceptive norethisterone enantate is potentially hepato- and nephro-toxic. More damage to the liver; and luteinization of theca and stroma cells of the ovaries occurred as a result of retinol hypervitaminosis. The brunt of toxicity and damage on the test organs after coadministration of both chemicals proved to be synergetic except on the ovarian tissues.

[Stereomorphometric studies of capillaries and nerve cells in the normal brain of the aged subject and in Alzheimer's disease]. / Etudes stéréomorphométriques des capillaires et des cellules nerveuses du cerveau normal chez le sujet âgé et dans la maladie d'Alzheimer.

Stereological investigations of putamen, frontal gyrus and precentral gyrus in Alzheimer's disease and in age-matched controls were performed with an optical electronic image analysis system (Leitz). In all layers of the frontal cortex, a significant atrophy of neuronal perikarya is observed in Alzheimer's disease compared with normally aged specimen. In putamen, a non significant decrease is measured in the area of nerve cells. The morphometric results of the capillary measurements show a 40% increase of the capillary volume in the brain cortex of the Alzheimer group compared with the controls. These results which are probably localized in cortex represent gross atrophy of the frontal brain in senile dementia of the Alzheimer type. No changes of this kind can be observed in young individuals (19-45 years) or the normal aged group (85-95 years).

[Quantitative-morphological changes of capillaries and neurons in the aging human putamen (author's transl)]. / Quantitativ-morphologische Altersveränderungen von Kapillaren und Neuronen im menschlichen Putamen.

Stereological investigations (Classimat) of the capillary net of 4 age-groups, ranging between 19 and 94 years, revealed significant increase of capillary volume and total length, and decreased intercapillary distances in the aging putamen. Neuronal size and shape measurements (Texture-Analyzer-System) of the same brain region showed significant changes between the young (19-44 y.) and oldest (85-94 y.) group, indicating senile atrophy of the neuronal perikarya. Quantitative image-analysis facilitates to evaluate new morphometrical data of the aging process in the human brain, which are important for a pharmacological concept of treating cerebral insufficiency symptoms.

The aging human cerebral cortex: a stereological characterization of changes in the capillary net.

Capillaries in the cerebral cortex of six age groups, ranging between 19 and 94 years (= 34 human brains) were stereologically investigated. Capillary parameters such as diameter, volume fraction, specific surface area, mean intercapillary distances and total length per unit cortex volume in patients older than 75 years were similar to those in young ones, 19 to 44 years old. Aged subjects between 64 and 74 years revealed increased capillary diameter, volume and total length per unit cortex volume, as well as decreased specific surface area. Frequency distributions in the same age indicate a real increase of capillary diameter and volume, as also an increase of these parameters on the level of blood vessels with diamteres greater than 8 micrometer, probably arterioles. The results of this study argue against the wide-spread assumption of a decreased blood supply in the cerebral cortex during old age. On the contrary, the capillary net is able to respond to changed metabolism and blood pressure.

[Stereological investigation in the cerebral cortex of aging subjects (author's transl)]. / Stereologische Untersuchungen am Grosshirncortex des alternden Menschen.

Involving cortical regions, capillaries of the human cerebrum of two 19 and 27 years old men, a 69 years old woman and a 72 years old man were stereologically investigated by optical-electronic image-analysis. The cortical capillary net work was demonstrated by the alkaline phosphatase activity. Each cortex region comprised a determination of the stereological parameters diameter, projected area, specific surface area, capillary distances in linear direction of TV-lines and total length per unit cortex volume. A comparison between different cortex regions revealed a good correlation between increased values of the diameter and the projected area, a decreased specific surface area and diminished capillary distances, which entail a shortened distance of oxygen diffusion through the cortical tissue. During aging a diminished capillary surface area, which results from increased values of diameter and projected area is compensated by shortened capillary distances. Presumably an augmented capillary length is due to a condensation of the capillary net per unit cortex tissue. The behaviour of the registered stereological parameters seems to be an accommodation of the capillary net in the human cerebrum to metabolic and circulatory changes during aging.

Quantitative studies in the cerebral cortex of aging humans.

The capillary network of the human cerebral cortex was morphometrically investigated in a young, aged and aged hypertonic group. In the aging cortex, augmented values of capillary diameter and volume are accompanied by smaller distances between capillaries and an extended length per unit cortex volume. An increased capillary diameter of the aged hypertonic group is probably due to a high blood pressure. The regulating influence of the surrounding astroglia and the extracellular fluid on capillaries seems to lack. In comparison to normotonic brains, higher distances between capillaries and a decreased capillary length were measured.