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Biomedical subjects

D R Cahill

Publications and source records attributed to D R Cahill.

15 recordsLinked to original sources
PubMed1989

Sectional anatomy of the larynx: implications for the transcutaneous approach to endolaryngeal structures.

A transcutaneous, transcricothyroid membrane approach to endolaryngeal structures is used for several techniques such as placement of electrodes for laryngeal electromyography and transcutaneous Teflon injection of the paralyzed vocal fold. The purpose of this study is to examine the sectional anatomy of the larynx with respect to the cricothyroid membrane and describe a suitable transcutaneous approach to endolaryngeal structures. Sixteen whole organ cadaveric larynges were frozen in clear gelatin to facilitate sectioning. Specimens were sectioned in the transaxial, sagittal, and coronal planes as well as 30 degrees, 45 degrees, and 60 degrees from the transaxial plane. For clinical orientation, the transaxial plane was defined as 90 degrees from the most anterior plane of the cricothyroid membrane. Sections were examined and angles and depths of penetration were measured with respect to the transcutaneous approach to endolaryngeal structures.

Female↗
PubMed1988

Magnetic resonance imaging of the wrist: normal cross sectional imaging and selected abnormal cases.

Using a small surface coil and limited field of view, the authors have generated 13 contiguous, 3 mm, transverse sections of the wrist of a cadaver. The identity of the structures recorded has been established by subsequent dissection of the cadaver. The article presents the 13 MR sections together with drawings identifying the recorded structures at each level. These anatomic sections are amplified by 7 transverse MR images showing alterations of the normal anatomy in clinical examples of wrist pathology.

Giant Cell Tumors↗
PubMed1988

Developmental changes in the extracellular matrix of the dental follicle during tooth eruption.

Eruption of the third and fourth mandibular premolars in the dog begins at 15 weeks of age, is dependent upon the dental follicle, and is complete by 23 weeks. Our study covered the period from 12 to 20 weeks, and revealed several changes in extracellular matrix structure and organization of the follicle which correlate with specific physiological events in eruption. First, the average DNA content per follicle reached a maximum at 14 weeks. Two weeks later, follicle size had increased 1.3- to 2.4- times. Second, the collagen content of follicles increased 2.5-fold over the study period, with two-thirds of this increase over the last four weeks. Type I collagen was the major collagen at all stages of follicular development. The amount of proteoglycan rose 45% from 16 to 20 weeks of age. Third, the ultrastructure of the dental follicle prior to eruption (12 weeks) indicated a disorganized interstitial connective tissue matrix; during eruption, two size classes of fibrils were observed which clustered together in linearly aligned bundles. Fourth, gel electrophoretic analyses resolved more than twenty follicle proteins with the major species a Mr = 95k glycoprotein. Immunoblotting demonstrated only one minor component was derived from serum. Comparison of noncollagenous proteins from different aged follicles indicated that three small polypeptides (Mr = 20-25 k) were present primarily at 16 weeks, the same time at which root elongation begins. A different sequence of changes was exhibited by two other proteins of Mr = 13 and 15 k. These findings may serve as biochemical markers of stages of dental follicle development and facilitate a search for local control mechanisms.

Aging↗
PubMed1988

Obturator hernia.

Obturator hernias are relatively rare. In the past 15 years at the Mayo Clinic, eight patients underwent nine operations for repair of 11 obturator hernias, which represented 0.073 per cent (11 of 15,098) of all hernias repaired at this institution. Elderly women with chronic disease were most frequently affected. Symptoms were usually intermittent; mechanical small intestinal obstruction was the most common presenting condition, followed by pain in the thigh or groin area. The Howship-Romberg sign was found in only two patients, and a correct preoperative diagnosis was made in only one patient. Midline abdominal incisions were made in all patients. Incarcerated ileum was the most frequently encountered organ in the hernia sac. Surprisingly, foci of endometriosis in the obturator defect accounted for symptoms in two patients with three obturator hernias. Right-sided obturator hernias outnumbered left, and bilateral obturator hernias were found synchronously in two instances and metachronously in one instance. The often debilitated state of the patients with obturator hernia and the frequent delay of diagnosis combined to produce significant operative morbidity and mortality rates.

Adult↗
PubMed1987

Prostate shape, external striated urethral sphincter and radical prostatectomy: the apical dissection.

In an anatomical study of 64 gross specimens the external striated urethral sphincter was reconfirmed to extend as a single unit from the proximal penile urethra to the bladder base. The configuration of the external striated urethral sphincter was variable and was related to the shape of the apical prostate. Two basic prostatic shapes were recognized, distinguished by the presence or absence of an anterior apical notch. Whether a notch existed depended upon the degree of lateral lobe development and the position of its anterior commissure. In radical prostatectomy knowledge of the variation in the shape of the prostatic apex can help the surgeon to achieve optimal urethral transection with maximal preservation of the external striated urethral sphincter and other tissues of the continence mechanism.

Aged↗
PubMed1987

Anatomy of the sural nerve complex.

The anatomy of the sural nerve complex in 20 cadaveric limbs was determined by dissection. The nerve usually consists of four named components: the medial sural cutaneous nerve, the lateral sural cutaneous nerve, the peroneal communicating branch, and the sural nerve. In most instances (80%), the sural nerve is formed in the distal portion of the leg by the union of the medial sural cutaneous nerve and the peroneal communicating branch. In 20% of cases, the peroneal communicating branch is absent. In such cases, the sural nerve is derived from the medial sural cutaneous nerve alone. The lateral sural cutaneous nerve is laterally situated and usually divides into medial and lateral branches. In a few cases, its medial division may contribute to the sural nerve through the peroneal communicating branch. The peroneal communicating branch can be of substantial caliber and may be useful as a source of nerve graft without complete sacrifice of the sural nerve. We describe a technique of isolation of the peroneal communicating branch for use as a nerve graft.

Humans↗
PubMed1987

Regional control by the dental follicle of alterations in alveolar bone metabolism during tooth eruption.

Tooth eruption is a localized, bilaterally symmetrical series of events which involves resorption and formation of alveolar bone on opposite sides of the tooth and requires the presence of the dental follicle. We examined the effect on eruption of selective surgical removal of parts of the follicle. Removal of either the basal or coronal halves of the follicle prevented eruption. Bone resorption and formation of an eruption pathway did not occur after removal of the coronal part of the follicle and bone formation did not occur after removal of the basal part of the follicle. Exposure and incisions of the follicle had no effect on eruption. We interpret these data to mean that the polarized resorption and formation of alveolar bone that occur around a tooth during eruption are regulated by the adjacent parts of the dental follicle.

Alveolar Process↗
PubMed1986

Cross-sectional anatomy of the pericardial sinuses, recesses, and adjacent structures.

Detailed drawings of four cross sections through the mediastinum which pass through the sinuses and recesses of the pericardial cavity, are presented. The drawings depict the location and extent of the pericardial sinuses, recesses, and their closely associated extrapericardial structures. Two previously unnamed recesses within the serous pericardium are defined and named, one the inferior aortic recess of the transverse sinus and the other, the right pulmonic recess of the transverse sinus. The terminology of the pericardial sinuses and recesses has been inconsistent, and the authors propose a nomenclature for standardizing the names of the recesses of the serous pericardium. Important anatomic pericardial relationships with regard to pericardial effusions and lymphadenopathy are discussed.

Diagnosis, Differential↗
PubMed1986

Lymphocytes capable of mediating delayed-type hypersensitivity reactions accumulate within sponge matrix allografts.

The rejection of sponge matrix allografts across H-2 barriers has generally been found to contain specifically sensitized cytotoxic T cells to donor alloantigen. There is one exception: sponge matrix allografts that differ only with respect to class II alloantigens do not contain specifically sensitized cytotoxic T cells. We therefore investigated the capacity of infiltrating cells removed from sponge matrix allografts to generate delayed hypersensitivity reactions after exposure to fresh alloantigen in a footpad assay. Cells infiltrating class I and II allografts were equally capable of eliciting delayed footpad reactions when injected with specific donor alloantigen into the footpads of naive responder strain mice. Allosensitized T-lymphocyte clones of helper or cytotoxic type were also capable of initiating delayed-type hypersensitivity (DTH) reactions in vivo. We conclude that rejecting allografts across class I or II alloantigenic barriers are infiltrated by cells capable of effecting DTH reactions, in addition to their capacity to exert specific helper or specific cytotoxic reactions. The results also support that both helper and cytotoxic T cells can participate in allospecific DTH reactions.

Animals↗
PubMed1975

The deceptive aortic root.

Coronal, horizontal, and sagittal sections through the mid-line are excellent ways of depicting the anatomical position of the aortic root and for studying its topographical relationship to the surrounding vascular structures. Minimal radiographic abnormalities or no abnormalities at all may be present with an enlarged ascending portion of the thoracic aorta. Thus, frontal chest roentgenograms obtained with high kilovoltage, fluoroscopy and left anterior oblique projections should be utilized routinely for the evaluation of the ascending aorta. Calcification of the aortic valve and of the coronary arteries and the study of aortic valve prosthesis also demand a dynamic study and the use of complementary views, such as lateral and both oblique projections.

Aorta, Thoracic↗