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PubMed1988

Developmental studies on the rat vomeronasal organ: vascular pattern and neuroepithelial differentiation. I. Light microscopy.

The origin and the developmental sequence of the rat vomeronasal organ and its vascular supply are followed by means of India ink injection in serial sections of celloidin-embedded embryos from the eleventh day of gestation up to birth. The anlage of the vomeronasal organ has been established by the twelfth day of gestation (E 12). It appears as a shallow longitudinal impression of the medial wall of the nasal pit. At day E 14, it separates from the epithelium of the primary nasal cavity, forming a tube. The lumen of the organ remains continuous with the nasal cavity frontally, but ends blindly at the edge of the primary palate dorsally. From day E 16 to E 18 the lateral surface of the tubular vomeronasal organ invaginates toward the lumen forming a wide longitudinal furrow. The lumen is bordered by the developing neuroepithelium and receptor-free epithelium by this time. The vomeronasal organ receives a separate arterial blood supply arising from septal tributaries of the olfactory artery, a branch of the anterior cerebral artery from the earliest stage of development. Blood from the vomeronasal complex is collected in the vomeronasal vein lying in the longitudinal furrow next to the receptor-free epithelium. The typical vascular pattern of the vomeronasal organ is established by the eighteenth day of gestation. At this time, the first capillary loops appear within the neuroepithelium and the vomeronasal vein can already be seen to extend along the long axis of the organ.

Animals↗

PubMed1988

Direct evidence that complex experience increases capillary branching and surface area in visual cortex of young rats.

Rats housed in complex environments with toys and other rats generate new synapses, and the expanding neuropil tends to spread apart existing blood vessels. Previous work demonstrated that weanling rats kept in complex environments had more closely packed capillaries, suggesting that new capillaries had sprouted into the newly added neuropil. The present study directly investigates the issue of new branching by using india ink perfusions of weanling rats kept for 30 days in a complex environment (EC), paired in standard caging (SC), or individual cages (IC) to examine the density of capillary branch points and the capillary surface area per unit tissue volume. EC rats had a greater density of branch points than the SC and IC littermates, a finding consistent with increased capillary sprouting. Capillary surface area per unit tissue volume and the number of branch points per unit of capillary surface area were also higher for EC rats. This suggests that blood vessels of EC rats branch off more often than those of animals kept in more standard conditions, and provides further evidence that complex experience can increase angiogenesis in cerebral cortex of postweanling rats.

Animals↗

PubMed1989

Vascularization of fetal cell suspension grafts in the excitotoxically lesioned adult rat thalamus.

Several studies have considered the establishment of vascularization in intracerebral solid transplants of neural tissue. The widely supported interpretation of the results is that the vascular network of the solid grafts is already present before implantation into the host brain. The situation is different when dissociated fetal tissue is transplanted as a cell suspension because in these conditions the fetal vascular network is disrupted. The present study has, therefore, been undertaken to follow the angiogenesis in a transplant of dissociated fetal cells implanted into the excitotoxically neuron-depleted thalamus. The vascular network is compared to that observed in the intact and in the lesioned thalamus both in terms of morphology of the capillaries and of the function of the blood-brain barrier (BBB). In the transplant, capillaries, stained by Indian ink, are very few in number and have very fine calibers during the first 20 days after grafting. Some structures can be identified as immature blood vessels at the electron microscopic level. The blood vessels are progressively more numerous in the graft and they demonstrate mature ultrastructural features 2 months after grafting. Last, there is no leakage of the BBB for peroxidase. The vascularization seems to follow a pattern of maturation comparable to that described during development in the literature. In contrast, in the lesioned area, there is a reactive angiogenesis: 10 days after the excitotoxic injection (shortest time studied), there are many wide caliber vessels with expanded perivascular spaces engorged with mesodermal cells. A microvascularization also develops transiently during the first two months. Capillaries are abnormal from the functional point of view, since there is a leakage of the BBB to macromolecules. The use of an experimental model in which transplant had to grow in a lesioned area permits to determine two types of vascularization: an apparently normal developmental timetable, normal morphological and functional characteristics, in the transplant; a reactive angiogenesis, in the lesioned area.

Animals↗

PubMed1994

A 13C solid-state NMR study of the structure and auto-oxidation process of natural and synthetic melanins.

This paper presents a 13C CP/MAS NMR study of the melanin pigments obtained through natural and synthetic origins: sepia-melanin from squid ink and three synthetic 5,6-dihydroxyindole-melanins prepared using different non-enzymatic oxidation pathways. The synthetic pigments can be distinguished from natural melanin by the absence of aliphatic carbons, thereby confirming the unreacted 3,4-dihydroxyphenylalanine and the proteinaceous origins of the aliphatic resonances in natural eumelanin. The spectra of selected non-protonated carbon resonances and those with only protonated carbon signals led to a quantitative analysis. An auto-oxidative experiment using a synthetic melanin, over a period of 130 h, has shown an unusually slow disappearance of hydrogen peroxide formed in situ. The 13C-NMR spectrum of the insoluble oxidized synthetic melanin compared to that before auto-oxidation clearly demonstrates that the oxidation process is associated with chemical changes within the pigment; i.e., carbonyl functional group formation and an increase of the non-protonated carbons fraction.

Animals↗

PubMed1993

Vascular morphometry of KHT and RIF-1 murine sarcomas.

Although tumor oxygenation and vascular structure have been studied extensively, previous work has most often been qualitative in nature. To clarify underlying physiological mechanisms, a more quantitative approach is needed. The current work considers two murine tumor lines of differing radiobiological hypoxic fraction (HF), the RIF-1 and the KHT fibrosarcomas. Following intravascular injection of India ink, histological sections were prepared and quantitated in terms of anatomical blood vessel-tumor cell distance distributions and vessel diameters. Vessel diameters increased with increasing tumor volume for RIF-1 tumors, while not changing significantly for the KHT. The fraction of the tumor within a given distance of the nearest blood vessel, varied as a function of: (i) tumor line, (ii) distance from tumor surface, and (iii) tumor volume. For small-volume tumors, intertumor differences in vessel-tumor cell distances correlated with differences in radiobiological HF, while for large-volume tumors, vessel-tumor cell differences were not significantly different between tumor lines. Combining current findings with previously determined intravascular oxyhemoglobin distributions in the same two tumor lines, it was apparent that not only is a substantial portion of the tumor volume beyond the expected oxygen diffusion limits of blood vessels, but, in addition, a relatively low percentage of these vessels is capable of supplying oxygen.

Animals↗

PubMed1995

Effect of intra-peritoneal fludarabine on rat spinal cord tolerance to fractionated irradiation.

The effect of fludarabine (9-beta-D-arabinosyl-2-fluoroadenine-5'- monophosphate), an adenine nucleoside analogue, on the tolerance of the spinal cord to fractionated irradiation was studied in a rat model. Anesthetized female Fisher 344 rats received irradiation to 2 cm of the cervical spine with a telecobalt unit (dose rate 1.14 Gy/min). Radiation was administered in two, four or eight fractions spread over a 48-h period with or without fludarabine. Animals assigned to combined therapy received two daily intraperitoneal injections of fludarabine (150 mg/kg) given 3 h prior to the first daily radiation fraction. It was found that fludarabine reduced the iso-effect dose required to induce leg paresis at 9 months after irradiation for all fractionation schedules. Dose modification factors of 1.23, 1.29 and greater than 1.27 were obtained for two, four and eight fractions, respectively. Fitting the data with the direct analysis method of Thames et al. with an incomplete repair model [18] showed that the potentiating effect of fludarabine may be mediated through reduction in the number of 'tissue-rescuing units' (InK). Alpha and beta values were slightly but not significantly decreased, whereas the alpha/beta ratio was unchanged. These features suggest that fludarabine did not significantly inhibit cellular repair processes but rather reduced the spinal cord tolerance by a fixed additive toxic effect on the same target cells. In rodent models, the combination of fludarabine and fractionated radiation has previously been found to yield a therapeutic gain, i.e., the drug enhanced tumor response to a greater extent than it reduced normal tissue tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Distribution of microorganisms with particular reference to encapsulated bacteria in kefir grains.

Propagable and non-propagable kefir grains in a form resembling cauliflower florets were observed by scanning electron microscopy (SEM) and light microscopy. In propagable grains short and long rod-shaped bacteria and yeasts formed separate colonies on the outside surface and inside. Internally, filaments which derived from capsules around the cells extended radially from a population of long rod-shaped bacteria. In non-propagable grains long rod-shaped bacteria with filamentous appendages were not observed, but only short rod-shaped bacteria and yeasts. Indian ink preparations showed presence of encapsulated bacteria in propagable grains and absence of these in non-propagable ones. The above results suggest that encapsulated bacteria are responsible for propagation of kefir grains.

Animals↗

PubMed1991

On the morphology of the terminal microvasculature during endochondral ossification in rats.

The investigation was carried out on the proximal tibia metaphysis by means of India ink-injection, reconstruction, corrosion casting combined with scanning electron microscopy, and transmission electron microscopy of thin sections. The terminal vasculature during endochondral ossification proved to be a labyrinth of interconnected sinusoidal complexes with bulbous buds invading the chondrocyte cavities of the growth plate. This system of vessels was canalized throughout. A special feature was the existence of endothelial pockets. The formation of the terminal microvasculature as a labyrinthine cavity during endochondral ossification, together with the still incompletely developed bone could be a weak point for compression injuries.

Animals↗

PubMed1991

Pityrosporum folliculitis in the Philippines: diagnosis, prevalence, and management.

Sixty-eight typical cases were studied to define the course of Pityrosporum folliculitis in a tropical setting. Contrary to reports in the literature, we found Pityrosporum folliculitis to be polymorphic. The "molluscoid" comedopapule was the most characteristic and common lesion, and it yielded consistently high spore counts. The face was commonly involved. To establish the diagnosis, we used direct microscopy of potassium hydroxide/Parker blue-black ink mounts of the lower poles of comedonal plugs. Pityrosporum folliculitis is common in the Philippines, although our adult controls had a low incidence of skin carriage of Pityrosporum orbiculare on the face compared with those reported in the West. Pityrosporum folliculitis coexisted with acne vulgaris in 56% of patients, and the addition of antimycotics to the acne regimen produced dramatic clearing of lesions.

Acne Vulgaris↗

PubMed1992

Verification of a formula for determination of preexcision surgical margins from fixed-tissue melanoma specimens.

BACKGROUND: Recently our group reported on the shrinkage of 199 malignant melanoma surgical-excision specimens. In that report, a multivariate analysis revealed that the age of the patient was the only factor that significantly affected the percentage shrinkage of a surgical specimen. In addition, a formula was presented that extrapolates the actual surgical margins (in vivo) from the (contracted) fixed-tissue pathology report measurement and the reported in vivo lesion diameter. OBJECTIVE: The goals of this study are to verify that shrinkage of surgical specimens is approximately 20% and that the margin formula can be successfully applied to a different group of patients. METHODS: Four hundred seven patients with malignant melanoma were prospectively enrolled to measure preexcision (outlined with ink) surgical margins, fixed-tissue (contracted) surgical margins, and overall specimen shrinkage. RESULTS: It is verified that overall shrinkage of cutaneous surgical specimens is approximately 20%. Surgical specimens from patients younger than 50 years of age have approximately 25% shrinkage. Those specimens from patients 50 to 59 years of age have approximately 20% shrinkage and those from patients 60 years of age or older have about 15% shrinkage. The surgical margins predicted by the margin formula were within +/- 3.5 mm of the actual measured surgical margin 86.5% of the time. CONCLUSION: The actual surgical margins (in vivo) of a malignant melanoma can be reasonably estimated from the fixed-tissue pathology measurement via the margin formula. The shrinkage of a surgical specimen is 15% to 25% depending on the patient's age.

Adolescent↗

PubMedDate not supplied

Effect of the secretin family of peptides on gastric emptying and small intestinal transit in rats.

We have compared the effects of the secretin family of peptides and their synthetic fragments on gastric emptying (GE) and small intestinal transit (SIT) using an unanesthetized rat model which simultaneously measures the GE and SIT of both solids and liquids. The meal consisting of 5% polyethylene glycol w/v, 5% Indian ink v/v and 20 non-digestible plastic beads was given intragastrically 10 minutes after the intraperitoneal injection of 0.5 ml of saline or peptides (2 and 5 micrograms/kg). Plasma secretin and the immunospecificity of secretin fragments were determined. In control rats, the t1/2 for the GE of both solids and liquids were 56 +/- 3.8 and 19 +/- 2.3 minutes, respectively. Liquids emptied faster than the solids and liquids travelled ahead of the solids in the intestine. Secretin (5 micrograms/kg) inhibited GE of both solids and liquids by 33-37%. Secretin delayed the SIT of the meal by approximately 35%. Fragments of secretin and of VIP had no effect on GE and SIT of both solids and liquids. The whole molecule of secretin was required to inhibit GE and to delay SIT of solids and liquids. Glucagon, PHI and growth hormone releasing factor (GHRF1-44) inhibited GE and SIT of both solids and liquids. For all peptides tested, the inhibition of SIT was proportional to the inhibition of GE suggesting that the prolongation of SIT was secondary to delayed GE. These observations indicate that the peptides of the secretin family inhibit GE and prolong SIT. Thus, the structural requirement required for the secretin family of peptides to effect their motor actions on the stomach is similar to that required for pancreatic enzyme secretion.

Animals↗

PubMed1984

Determining the recipient site for a sensory island pedicle.

When performing a sensory island transfer for restoration of sensibility to an area of pinch, one must be accurate in determining the recipient site. We present a simple and precise means of determining the recipient site for a sensory island transfer by ink-blotting the areas of contact of the thumb and index finger.

Amputation, Traumatic↗

PubMed1987

Blood supply of the subcutaneous tissue of the upper limb and its importance in the subcutaneous flap.

Vascularization of the subcutaneous tissue of the upper extremity is described. Injection of coloured latex or India ink and gelatine solution showed the principal sources of the blood supply. Microdissection and transclarification of Spalteholz allowed for the study of the direct and indirect arterial branches which form the principal network of the subcutaneous tissue. The findings are of practical importance since the subcutaneous tissue can be used as a separate flap for covering soft tissue defects of the forearm and hand.

Adult↗

PubMed1989

Documentation of the first web space angle.

We describe a new method of measuring adduction contractures of the thumb by using stent mould casts of the first web, which are sectioned sagittally to give an accurate clinical angle at their cut section. This can be recorded from ink impressions. This method has been used successfully in 65 cases and appears more accurate than other methods.

Casts, Surgical↗

PubMed1988

Detection of neovascular signals in a 3 day Walker 256 rat carcinoma by CW Doppler ultrasound.

An animal model was used to study tumor blood flow by the Doppler CW technique. The objective was to determine when neovascularity could be detected as a function of tumor size and time since transplantation. A Walker 256 carcinosarcoma tumor was inoculated into the flank of 17 Sprague-Dawley rats. Doppler examinations, using a 9 MHz CW probe, were performed daily from day 0 to day 7. The contralateral flank was used as a control. No signals were detected from the control side nor from the inoculated side until day 3. By day 3, Doppler signals could be easily detected in all tumor implants with a minimum weight of only 50 mg. These signals showed a mean systolic frequency shift of 3.3 +/- 0.47 kHz at 3 days and 3.46 +/- 0.58 kHz at 7 days. The diastolic Doppler shifted frequency was 1.78 +/- 0.31 kHz at 3 days and 1.88 +/- 0.23 kHz at 7 days giving a Pourcelot index of 0.47 +/- 0.1 at 3 days and 0.46 +/- 0.09 at day 7. These figures indicate the presence of low impedance vessels with high velocity flow such as has been reported in many human tumors. The vascular morphology was further evaluated by digital angiography which demonstrated coincidence between the site of the high velocity Doppler signals and the presence of arteriovenous anastomoses manifested by simultaneous arterial and venous filling. Further infusion techniques using India ink or Microfil showed the chaotic arrangement of tumor vessels located around the growing edge of the tumor implant. The development of such vascularity is a well-recognized prerequisite for tumor growth and invasion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗

PubMed1984

Pathogenesis of hypoxic-ischemic brain injury in a perinatal rodent model.

Exposure of immature rats to 8% oxygen after unilateral carotid artery ligation (UCL) causes metabolic, neurochemical and histopathological changes in the ipsilateral forebrain that resemble those in human perinatal hypoxic-ischemic encephalopathy. Regional cerebral perfusion in this model was examined by visual analysis of India ink trapped in cerebral vessels and measurement of [14C]iodoantipyrine [( 14C]IAP) and [3H]flunitrazepam extraction into the brain. UCL alone reduced [14C]IAP accumulation in the ipsilateral hemisphere by 20% and hypoxia superimposed on UCL progressively reduced ipsilateral hemisphere perfusion by 71% at 2 h. Hypoxia probably injures neurons in this model by causing a critical reduction in cerebral perfusion, an effect which also appears to be important in the human disorder.

Animals↗

PubMed1985

Maintenance of the integrity of the blood-brain barrier in the rat during an in situ saline-based perfusion.

Integrity of the blood-brain barrier to the small polar tracer mannitol was maintained for up to 30 min during an in situ perfusion of the brain with a saline-based solution containing the metabolic inhibitor 2,4-dinitrophenol. The patency of the capillary bed after perfusion was demonstrated by injecting a solution of Indian ink and gelatin, and ultrastructural examination showed the microvasculature to be well preserved. These findings suggest that the blood-brain barrier can be studied under conditions that are independent of normal cerebral function and metabolism.

2,4-Dinitrophenol↗

PubMed1988

Structural modifications in biosynthetic melanins induced by metal ions.

A number of transition metal ions with a wide distribution in biological systems, e.g., Cu2+, Co2+ and Zn2+, are shown to affect markedly the chemical properties of melanins formed by the tyrosinase-catalysed oxidation of dopa. Acid decarboxylation and permanganate degradation provide evidence that melanins prepared in the presence of metal ions contain a high content of carboxyl groups arising from the incorporation of 5,6-dihydroxyindole-2-carboxylic acid (DICA) into the pigment polymer. Naturally occurring melanins from cephalopod ink and B16 mouse melanoma were found to be much more similar to melanins prepared in the presence of metal ions than to standard melanins prepared in the absence of metal ions. These results suggest that the presence of carboxylated indole units in natural melanins is probably due to the intervention in the biochemical pathway of metal ions which, as recently shown, catalyse the formation of DICA versus 5,6-dihydroxyindole in the rearrangement of dopachrome.

Animals↗