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Biomedical subjects

W P Maher

Publications and source records attributed to W P Maher.

12 recordsLinked to original sources
PubMed1992

Biocompatibility of retrograde filling materials in the ferret canine. Amalgam and IRM.

Periapical tissue response to retrograde fillings of amalgam and IRM were compared in the mandibular canine of the adult male ferret. Teeth were cleaned and shaped with a standard technique and obturated with gutta-percha. The root apex was then exposed and retrofillings were placed. The animals were grouped according to observation periods of 5, 10, and 15 weeks. At the proper time the animals were killed and the lower canine tooth along with the surrounding bone was removed. The tissue blocks were examined clinically, radiographed, and prepared for histologic examination. The clinical and radiographic examination indicated both materials to be well tolerated by periapical tissues. Microscopic examination of amalgam specimens showed a decrease in inflammation and the formation of a fibrous capsule over the 15-week period. IRM specimens showed persistent inflammation and slower healing potential.

Alveolar Process↗
PubMed1990

Palmar-digital arterial networks in fifty pairs of human fetal hands: arteriographic models for clinical consideration.

Arterial networks in 50 pairs of human fetal hands, made visible by perfusion with radiopaque media, were compared between right and left hands. The imaged primary arterial networks in the fetal hands were also compared with those in adult human and rhesus monkey hands. It was found that superficial arch configurations and their primary ramifications are bilaterally similar in human fetal hands. The configurations of the primary arterial networks are established very early in prenatal growth and may be maintained into adulthood. The similarities in the arterial network arrangements between fetal human and rhesus monkey hands suggest that the rhesus monkey hand could provide an appropriate model for studies of surgical neurovascular anastomosis.

Angiography↗
PubMed1988

Microvascular networks in tympanic membrane, malleus periosteum, and annulus perichondrium of neonatal mongrel dog: a vasculoanatomic model for surgical considerations.

India-ink-imaged blood-vessel networks in cleared tympanic membranes and adnexa from ten neonatal dogs were examined microscopically and photographed. The major significance of the study lies in documentation of a dual source of arterial supply, a bilaminar relationship of arterial and venous plexuses intrinsic to the tympanic membrane, and a consistent major venous pathway relative to a definite locus (pars flaccida of the membrane). Illustration of all three types of blood pathways (arteries, veins, and capillaries) provides new vasculoanatomic data that are essential to ear surgery, specifically--to myringotomies and myringoplasties. A comparison was made between dog and human tympanic membrane structures and their arterial supplies. Close similarities suggested that dog tympanic membrane might serve as a suitable model for development of innovative surgical procedures and as a model for rehearsal of difficult techniques. The results of this investigation provide a valuable caveat to otologists.

Animals↗
PubMed1986

Arterial venous and lymphatic pathways intrinsic to the palate and fauces (implicated routes for metastatic lesions).

Since metastatic lesions of the palate are known to spread primarily via lymphatics and secondarily via veins it would seem likely that knowledge of their distribution would be essential to clinico-pathologic interpretation. Arteries, veins and lymphatics intrinsic to human fetal and neonatal dog palates were ascertained by perfusing each vessel type with a different coloured dye. Stereomicroscopic observations determined that the three vessel types are so intricately intermingled that companionship in distribution does not exist. It was determined that the greater palatine and nerve enter the palatal area via the greater palatine foramen and are constant companions to one another as they ramify in the palatal mucoperiosteum. The palatal venous plexus converges in the posterior palate forming a single vein that descends to the pharynx where it joins the pharyngeal venous plexus. Hard and soft portions of the palate do not drain separately to infratemporal and pharyngeal venous plexuses. Arterial and venous networks form three strata (mucosal, submucosal and periosteal) but the lymphatic network forms only two strata (mucosal and submucosal). Images of blood and lymph vessels were observed coursing into the bony palate via canals of Volkmann but no images of lymph vessels were observed coursing into bone. The bony palate appears to be alymphatic. Fibrous connective tissue investing the bony palate (periosteum) and that surrounding neurovascular bundles (connective tissue sheaths) appears to function as a barrier to lymphatic ingrowth since both structures did not contain imaged lymphatic vessels. However, the fibrous connective tissue band at the palatal midline (median palatal raphe) does not present a barrier to lymphatic continuity since imaged lymphatic vessels were observed extending across the midline. Lymphatic afferentia exit the palatal area in stromata investing the palatoglossus and palatopharyngeus muscles and subsequently join lymphatic networks intrinsic to the tongue and pharynx. Hence arteries enter while veins and lymphatics exit the palatal area at separate locations in the posterior palate. Distribution of lymphatic vessels were found to coincide with clinical observations as to direction of spread of malignant lesions from the posterior palate and upper faucial area to the tongue and pharynx. The study also provided a vasculo-anatomic basis for surgical consideration specific to cleft palate reconstruction and palato-pharyngeal hiatus closure.

Animals↗
PubMed1985

Arterial, venous and lymphatic pathways in dorsal mucosa of dog tongue (implicated routes for metastatic lesions).

Because metastatic lesions of the tongue are known to spread primarily via lymphatics and secondarily via veins, it would seem likely that knowledge of their distribution would be essential to clinico-pathologic interpretation. Although there is unaminity of opinion regarding lymphatic afferent pathways from the tongue to regional lymph nodes, unanimity of opinion is lacking regarding distribution of lymphatics and veins in the dorsal mucosa. Pivotal questions are: Do lymph vessels in the dorsal lingual mucosa extend across lines of fusion of embryonic lingual processes (lingual raphe and sulcus terminalis)? Do anterior and posterior portions of the tongue drain separately? To resolve these problems and to clearly delineate arteries, veins and lymphatics, each vessel type was perfused with a different colored perfusate. Imaging techniques provided by perfusion methods demonstrated precisely that the lymphatic network extends uniformly throughout the mucosa from tip to base crossing the sulcus terminalis in route and from border to border crossing the median lingual raphe. Mucosal veins are peltate in form anteriorly, but are pennate in form forward to the vallate papillae. The distribution characteristics of these vessel types provides opportunities for multidirectional spread of metastatic lesions. Because spread via both routes is rapid and multidirectional, it becomes clear that chemotherapy and radiotherapy may be preferable to surgery. The latter is frequently mutilating and sometimes the patient is left without capabilities of phonation and deglutition. Furthermore, radical surgical procedures do not provide assurance that the patient has been entirely separated from the malignancy.

Animals↗
PubMed1981

Artery distribution in the prenatal human maxilla.

Differing opinions concerning the human maxilla and its morphogenesis lead to different concepts concerning the intrinsic arterial supply to the anterior portion of the maxilla and its incisors. Microscopic and radiographic analyses of appropriately perfused infraorbital and posterior superior alveolar arteries in more than 100 human fetuses from six months to term reveal that the posterior superior alveolar artery courses to the facial midline, supplying branches to the incisors and to the posterior teeth. This observation differs clearly from the classical description that the anterior superior alveolar artery, a branch of the infraorbital artery, supplies the anterior maxillary segment and its incisors as seen in the postnatal life.

Alveolar Process↗
PubMed1977

Distribution of palatal and other arteries in cleft and non-cleft human palates.

Cleft lip and cleft palate are two possible effects of fusion failure of embryonic facial processes. Aberrant facial morphogenesis suggest aberrant arterial distribution. Prompted by surgical need, studies detailing major branches of the third or pterygopalatine portion of the maxillary artery acquire practical significance. Therefore postomortem arteriographic studies were undertaken to ascertain location of these major arteries and their branches in twelve near-term human fetuses. Comparison was made between arterial distributions in three cleft and nine non-cleft fetal palates. The question of bilateral symmetry was examined. It is known that these major branches are commonly present on both sides, but the study revealed numberous variations in each facial half in both cleft and non-cleft palates. Variation implies morphologic contradiction with sterotype presentations. So numberous are the variations that occasionally they may account for sudden and unexpected hemorrhage during surgery/and retarded healing or sphacelus of flaps following surgery.

Alveolar Process↗