Biomedical subjects

N A Monteiro-Riviere

Publications and source records attributed to N A Monteiro-Riviere.

62 records · Page 4Linked to original sources

PubMed1984

Ultrastructural characterization of the nasal respiratory epithelium in the rat.

This ultrastructural study of the respiratory epithelium of the rat nasal mucosa revealed six morphologically distinct cell types: goblet cells, basal cells, ciliated cells, nonciliated columnar cells, cuboidal cells, and brush cells. The latter three have not been previously characterized in the rat nasal mucosa by transmission electron microscopy. Cuboidal cells observed on the conchae and lateral wall had short apical microvilli which were less dense than the microvilli of the nonciliated columnar cells. Nonciliated columnar cells also identified on the conchae and lateral wall had short microvilli and an extensive network of smooth endoplasmic reticulum in the apical region. The brush cell had distinct ultrastructural features; it was pear-shaped, with the broad base adjacent to the basement membrane and large microvilli on the surface. Microfilaments, microtubules, vesicles, and paired cisternae were found in the apical cytoplasm. Brush cells occurred singly on the conchae and lateral wall but were not identified in the respiratory epithelium of the nasal septum. These findings indicate the complexity of cell types composing the rat nasal respiratory epithelium.

Animals↗

PubMed1981

Interfollicular smooth muscle in the skin of the domesticated pig (Sus scrofa).

An interfollicular smooth muscle that spans the triad of hair follicles has been identified in the skin of the domesticated pig (Sus scrofa). This muscle has been previously noted by other investigators and identified as an arrector pili muscle. However, it cannot be interpreted as such for the following reasons: 1) It lies opposite the arrector pili muscle on the follicle; 2) the orientation of its fibers is perpendicular to those of the arrector pili; 3) the two muscles are not continuous; their attachments are different; and 4) contraction of the interfollicular muscle would have little effect on erection of the hairs. Based on structural evidence, it is postulated that upon contraction the muscle draws the base of the three aligned follicles together into a triangular conformation. In so doing, it may rotate the outer two follicles of the triad. Its specific functional role is unknown.

Animals↗

PubMed1981

Light microscopic morphology of low resistance skin points in the guinea pig.

This study compares the light microscopic structure of low resistance skin points (LRSP) to high resistance skin points (HRSP) of the guinea pig, Previously, LRSP have been shown to coincide with acupuncture loci. Epidermal nuclei and dermal nuclei were counted at both LRSP and at control points or HRSP. In addition, hair follicles, blood vessels, and sebaceous nuclei were likewise quantitated. This data, collected in a blind manner, was then subjected to statistical analysis using a nested analysis of variance and a Student's "t" test. The former test indicated an increase in density of hair follicles at LRSP, while both demonstrated a decrease in dermal nuclei at LRSP. An interesting finding is that the epidermis at both LRSP and HRSP is indistinguishable at the light microscopic level. This was indicated by both statistical procedures. Finding of a Haarscheibe, an aggregation of Merkel cell-neurite complexes, only at HRSP tends to preclude its role as an acupuncture neurotransducer. Finally, there appeared to be no obvious qualitative differences between LRSP and HRSP observable at the light microscopic level.

Acupuncture Therapy↗

PubMedDate not supplied

Comparison of integrins in human skin, pig skin, and perfused skin: an in vitro skin toxicology model.

Integrins alpha2beta1, alpha3beta1, and alpha6beta4 are expressed in the epidermis, and play an important role in wound healing and/or epidermal-dermal interaction. These integrins may provide a new perspective into the understanding of wound healing and vesication. The isolated perfused porcine skin flap (IPPSF) has been shown to be an in vitro model for chemical-induced vesication. In order to determine whether the IPPSF could be utilized to study skin diseases mediated by integrins, the expression of integrins alpha2beta1, alpha3beta1, and alpha6beta4 was studied in human skin, pig skin, and the IPPSF using immunohistochemical staining. Immunostaining of both alpha2beta1 and alpha3beta1 was primarily located at the periphery of the basal keratinocytes in human skin. Similarly, alpha2beta1 was expressed in the stratum basale layer of the epidermis in both pig skin and the IPPSF after 8 h of perfusion. These antibodies defined the periphery of the pig basal keratinocytes more diffusely than that of human cells. However, the alpha3 antibody outlined the keratinocytes in all epidermal layers of the IPPSF and in the pig skin. In human skin, pig skin, and the IPPSF, alpha6beta4 stained exclusively at the basal pole of the basal keratinocytes, and showed a continuous linear labeling along the epidermal-dermal junction. The IPPSF showed stronger immunoreactivity with the antibody against beta4. Furthermore, the distribution of alpha6beta4 in 5.0 mg/ml of bis-(2-chloroethyl) sulfide (sulfur mustard, HD)-induced blisters was examined in the IPPSF. The alpha6beta4 staining was exclusively located on the epidermal side (roof) of the blister. In addition, alpha6beta4 staining was not linear but disrupted and patchy. These findings suggest that any destruction of alpha6beta4 may weaken the epidermal-dermal junction, thereby leading to HD-induced vesication. This study demonstrates that the IPPSF expresses similar integrins to those of human skin, and the distribution of alpha6beta4 in the IPPSF blisters caused by HD is comparable to that of some human basement membrane blistering diseases. Therefore, the pig and the IPPSF prove to be ideal models to study the role of integrins in wound healing and blistering diseases occurring at the epidermal-dermal junction.

Animals↗

PubMedDate not supplied

Immunohistochemical characterization of the basement membrane epitopes in bis(2-chloroethyl) sulfide-induced toxicity in mouse ear skin.

Sulfur mustard (bis(2-chloroethyl) sulfide (HD)), a potent cutaneous vesicant and bifunctional alkylating agent, produces significant time-dependent histopathological changes in the skin of the mouse. The right ears of male CD1 mice were exposed topically to 5.0 microl of 195 mM (0.16 mg) HD in dichloromethane and harvested at 6, 12, 18 and 24 h. The left ear control was dosed with 5.0 microl of dichloromethane. In all controls and HD-treated mouse ear, moderate immunofluorescence staining was seen at the epidermal-dermal junction with bullous pemphigoid (BP), epidermolysis bullosa acquisita (EBA) and laminin (Lam), and light staining was observed with bullous pemphigoid 180 (BP180), fibronectin (Fn) and type IV collagen (Coll IV). Mouse anti-human monoclonal antibodies for GB3, L3d and 19-DEJ-1 (Uncein) did not cross-react. In microvesicles, BP, BP180 and Fn showed areas of light focal epidermal staining and homogeneous dermal staining, and EBA, Lam and Coll IV showed moderate dermal staining. Both BP and Fn exhibited weak, inconsistent staining with time. Immunoelectron microscopy (IEM) revealed similar results, with an increase in cell damage from 6 to 24 h, which corresponded to a decrease in staining intensity. Cell proliferation, expressed as the growth fraction of proliferating cell nuclear antigen (PCNA), showed an increase in cell damage. The growth fraction was lower in the inner ear and showed time-dependent differences. The immunofluorescence and IEM results indicate that HD causes an undulating inconsistent separation in the uppermost lamina lucida with focal cleavage into the lower portion of the basal keratinocytes just above the plasma membrane. Although this pattern of separation differs from other in vivo models in which the split occurs exclusively within the lamina lucida, this should not preclude its role as a screening model to study the effects and development of specific prophylactic and therapeutic strategies.

Animals↗

PubMedDate not supplied

Use of methyl salicylate as a simulant to predict the percutaneous absorption of sulfur mustard.

Exposure to chemical vesicants such as sulfur mustard (HD) continues to be a threat to military forces requiring protectant strategies to exposure to be evaluated. Methyl salicylate (MS) has historically been the simulant of choice to assess HD exposure. The purpose of this study was to compare the percutaneous absorption and skin deposition of MS to HD in the isolated perfused porcine skin flap (IPPSF). The HD data were obtained from a previously published study in this model wherein 400 microg cm(-2) of ](14)C[-MS or ](14)C[-HD in ethanol were topically applied to 16 IPPSFs and experiments were terminated at 2, 4 or 8 h. Perfusate was collected at increasing time intervals throughout perfusion. Radioactivity was determined in perfusate and skin samples. Perfusate flux profiles were fitted to a bi-exponential model Y(t) = A(e(-bt) - e(-dt)) and the area under the curve (AUC), peak flux and time to peak flux were determined. Sulfur mustard had more pronounced and rapid initial flux parameters (P < 0.05). The AUCs determined from observed and model-predicted parameters were not statistically different, although the mean HD AUC was 40--50% greater than MS. The HD skin and fat levels were up to twice those seen with MS, but had lower stratum corneum and residual skin surface concentrations (P < 0.05). Compared with other chemicals studied in this model, HD and MS cutaneous disposition were very similar, supporting the use of MS as a dermal simulant for HD exposure.

Administration, Cutaneous↗

PubMedDate not supplied

The isolated perfused equine skin flap. Preparation and metabolic parameters.

A model for the study of equine cutaneous physiology, pharmacology, and toxicology was developed. Four 4 x 12 cm and twenty-one 6 x 12 cm single-pedicle axial pattern skin flaps based on the caudal superficial epigastric artery, and eight 6 x 12 cm flaps based on the saphenous artery and medial saphenous vein, were raised and sutured in a tubed configuration. On day 2, each flap was removed, the artery was cannulated, and the flap was perfused with a modified Krebs-Ringer's albumin-based medium for at least 6 hours. Flap viability was assessed by glucose use, lactate production, and histologic examination at the end of the perfusion period. The 4 x 12 cm flaps had evidence of skin necrosis, but the 6 x 12 cm flaps remained histologically viable. Results were compared to those previously reported from perfusion of porcine skin flaps based on the caudal superficial epigastric artery. While the ratios of glucose use to lactate production were similar, equine flaps used less glucose and produced less lactate per gram of tissue than similar pig flaps. Equine skin flaps perfused by saphenous vessels used more glucose and produced more lactate than flaps perfused by caudal superficial epigastric vessels. These results indicate that conclusions drawn from cutaneous physiology studies should not be extrapolated across species lines and that site-specific skin should be used for cutaneous physiology, pharmacology, and toxicology studies. The identified skin flaps may have applications in equine reconstructive surgery.

Abdomen↗

PubMedDate not supplied

Indirect immunohistochemistry and immunoelectron microscopy distribution of eight epidermal-dermal junction epitopes in the pig and in isolated perfused skin treated with bis (2-chloroethyl) sulfide.

Sulfur mustard (bis [2-chloroethyl] sulfide, HD) is a potent cutaneous vesicant that causes gross blisters by separation of the epidermal-dermal junction (EDJ). The EDJ of the skin is a highly specialized and complex structure composed of several components and plays a major role in the integrity of the skin. The isolated perfused porcine skin flap (IPPSF) was dosed with 0.2 mg/ml (n = 4), 5.0 mg/ml (n = 4), and 10.0 mg/ml (n = 5) HD or ethanol (n = 4) for 8 hr (dose-response study) and 10.0 mg/ml HD or ethanol for 1, 3, 5, and 8 hr (n = 4/treatment) (time-response study). Successful EDJ mapping was carried out in normal pig skin (NPS), ethanol-treated IPPSFs, and HD-treated IPPSFs using the following antibodies: laminin, type IV collagen, fibronectin, GB3 (Nicein), bullous pemphigoid (BP), and epidermolysis bullosa acquisita (EBA). Two mouse anti-human monoclonal antibodies, L3d and 19-DEJ-1 (Uncein), did not cross-react with the EDJ of the pig. Antibody staining in NPS, ranging from very intense for laminin and type IV collagen to weak for fibronectin, was generally more discrete than in the IPPSF. No differences in staining were noted between the ethanol and nonblistered areas of the HD-treated IPPSFs. In HD-blistered areas, BP stained only the epidermal hemidesmosomes, and laminin, fibronectin, and GB3 stained primarily the dermis with fragments attached to the basal pole of the stratum base cells, while type IV collagen and EBA stained only the dermis. Mapping of these epitopes determined that the precise plane of EDJ separation in the HD-treated skin occurred beneath the hemidesmosomes within the upper portion of the lamina lucida. The conservation of human epitopes in the EDJ of the pig further emphasizes the similarities between human skin and pig skin. Therefore, pig skin and the IPPSF may be used to study HD-induced vesication and blistering diseases.

Animals↗