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Biomedical subjects

M S Davis

Publications and source records attributed to M S Davis.

At least 19 recordsLinked to original sources
PubMed1998

Clinical assessment of gas exchange in mature horses.

There are limited methods of assessing pulmonary function in horses at rest. We developed clinical techniques to measure gas exchange efficiency in horses and evaluated 3 groups of horses that were 1) asymptomatic based on auscultation with rebreathing, transtracheal aspirate cytology, and thoracic radiographs (n = 6), 2) asymptomatic at rest but symptomatic with rebreathing (n = 11) and 3) symptomatic at rest (n = 9). Blood samples were obtained from the transverse facial artery and jugular vein. Maximal end-tidal CO2 tension (PETCO2) was measured by an infrared capnograph through a facemask. Alveolar O2 tension, dead space fraction (V(D)/V(T)), and physiological shunt fraction (Q(S)/Q(T)) were calculated using standard formulae. Arterial O2 tension in Group 1 horses (mean +/-s.d.103+/-3 mmHg) was significantly higher than in Group 2 or Group 3 horses. Q(S)/Q(T) in Group 1 horses (0.37+/-0.98%) was significantly lower than in Group 2 and Group 3 horses. Mean +/-s.d.V(D)/V(T) in Group 1 horses (-18.2+/-3.1) was significantly lower than Group 3 horses but not Group 2 horses.

Aging↗
PubMed1998

Phaeohyphomycosis caused by Phaeoacremonium inflatipes.

Phaeoacremonium inflatipes, one of three species previously classified as strains of Phialophora parasitica, was identified as the causal agent of a subcutaneous infection of the left foot of an 83-year-old woman from South Carolina. The patient had a granulomatous growth over the anteromedial aspect of her left foot. It was surgically excised, which led to complete healing without complications. Tissue sections of the excised mass stained with hematoxylin and eosin and Gomori's methenamine silver strains showed many septate hyphal elements of various lengths, some exhibiting brownish pigment in the cell walls of the hyphae. Portions of the tissue, when cultured, yielded many colonies which were initially glabrous, off white becoming velvety, greyish brown on aging. Microscopically, their hyphae were septate, branched, and phaeoid and bore lateral and terminal, erect, septate conidiophores. The conidiogenous cells (phialides) were terminal or lateral, mostly monophialidic, subcylindrical to spinelike in shape, and constricted at their bases and bore funnel-shaped, inconspicuous collarettes at their tips. The conidia were subhyaline, oblong, and ellipsoid to allantoid.

Aged↗
PubMed1997

Videothoracoscopic treatment of hepatic hydrothorax.

Hepatic hydrothorax occurs frequently in ascites arising from communications in the diaphragm between peritoneal and pleural cavities. Numerous treatments have been described but are of limited utility due to invasiveness and poor success rate. We describe a case of hepatic hydrothorax in which the pore in the diaphragm was documented photographically and in which successful resolution was achieved with videothoracoscopic suture ligation and talc pleurodesis.

Ascites↗
PubMed1997

Effects of spatial frequency of a vertically striped rotating drum on vection-induced motion sickness.

PURPOSE: The present study investigated the effects of differential spatial frequencies of a vertically striped, horizontally rotating drum on the observer's frequency of eye nystagmus, perceived velocity of self-motion, and symptoms of motion sickness. METHODS AND RESULTS: Two experiments were conducted. In Experiment 1, each of 10 subjects viewed 1 min of an optokinetic rotating drum at the speed of 10 rpm covered with 6, 12, 24, 48, and 96 pairs of black and white stripes, presented in counterbalanced order. The results indicated that subjects perceived significantly stronger circular vection (p < 0.05) and generated significantly higher frequencies of eye nystagmus (p < 0.05) when they were viewing 24 pairs of black and white stripes than when they were viewing any of the other combinations of 6, 12, 48, or 96 black and white stripes. In Experiment 2, 100 highly susceptible subjects viewed 16 min of an optokinetic rotating drum covered with one of the five different numbers of black and white stripe pairs: 6, 12, 24, 48, and 96. The results indicated that subjects in the group viewing 24 moving contrasts perceived significantly stronger circular vection (p < 0.001), reported significantly more severe symptoms of motion sickness (p < 0.001), and showed significantly greater ratios of EGG 4-9 cycles per minute spectral intensity between drum rotation and baseline periods (p < 0.004) than those in the groups of viewing 6, or 96 moving contrasts. CONCLUSION: These results demonstrated that the severity of vection-induced motion sickness is affected by differential spatial frequencies of the stripes of the rotating drum and may be affected by number of horizontal eye movements.

Adolescent↗
PubMed1997

Effects of toothbrush design and brushing proficiency on plaque removal.

A single-blind, short-term cross-over clinical trial compared the plaque removal performance of three commercially available manual toothbrushes. A sample of 25 dental hygiene students, 19 to 42 years old, served as participants. On 3 separate occasions, participants were instructed to refrain from toothbrushing or flossing for 24 hours before clinical trials. A prebrushing plaque index using disclosing solution was performed on each participant. One of the 3 test brushes was then randomly dispensed to each participant, and they were allowed to brush for 90 seconds without the aid of a mirror. A postbrushing plaque index was then performed on each participant. This procedure was repeated 2 more times at 2-week intervals so that each participant was tested with all 3 toothbrushes. Previous studies of this kind using random participant samples have suggested that brush design does indeed affect the efficacy of plaque removal. This study used participants who were well versed on efficient toothbrushing technique to determine if improved brushing skills would overshadow advantages in toothbrush design. No significant differences in performance were detected between the test brushes for any of the three scored areas.

Adult↗
PubMed1996

Occupational hazards of operating: opportunities for improvement.

The emergence of hepatitis C virus compels us to refocus on protecting ourselves, our coworkers, and our families from potential illness, disability, or death. As blood-borne pathogens continue to evolve and mutate, the best option available is to prevent exposure. Surgeons have the opportunity to prevent the majority of exposures by utilizing currently available technology and knowledge. Surgeons should see, use, and evaluate a variety of safety-engineered devices, because their feedback can lead to improvements in technology. Education, communication, and access to safer technology will motivate surgeons to adopt safer behavior patterns. Provided with information and tools, we can change through self-motivation.

Attitude of Health Personnel↗
PubMed1996

Chromoblastomycosis caused by Exophiala spinifera.

We report the second case of chromoblastomycosis caused by Exophiala spinifera; this is the first known case in the United States. Examination of biopsied tissue showed thick-walled, internally septated, chestnut brown muriform cells (sclerotic bodies) within multinucleated giant cells present in the dermis that were characteristic of chromoblastomycosis. The individual cells within the muriform cells disarticulated from the outer wall of the parent cell and from each other to form endoconidia within the outer walls of the parent cells. After fracture of the outer walls, the endoconidia were released. This unique process of endoconidial formation in vivo for the propagation of muriform cells was observed for the first time. Initial treatment with itraconazole and 5-fluorocytosine followed by treatment with itraconazole and heat resulted in marked improvement in the patient's lesions. This infection reiterates the fact that the dematiaceous fungus E. spinifera, a well-known etiologic agent of phaeohyphomycosis, can cause more than one type of infection and supports earlier observations that chromoblastomycosis and phaeohyphomycosis represent extremes of a continuum of infections.

Antifungal Agents↗
PubMed1995

Mycoleptodiscus indicus: a new etiologic agent of phaeohyphomycosis.

Mycoleptodiscus indicus, a dematiaceous hyphomycete, was identified as the causal agent of subcutaneous infection in the knee of a 72-year-old male gardener residing in coastal South Carolina. The patient had Wegener's granulomatosis and immunodeficiency. Synovial fluid and biopsy tissue sections from the prepatellar bursa stained with hematoxylin and eosin, periodic acid-Schiff, and Gomori methenamine silver stains revealed branched, septate hyphae and many moniliform hyphal elements. When tissue sections were stained by the Fontana-Masson procedure, melanin pigment in the hyphal cell walls and at the septa was evident. A velvety, dematiaceous mold was isolated from both synovial fluid and the biopsy tissue. Sporulation was induced by exposure of slide cultures on potato dextrose agar to UV light for 12 h at 25 degrees C followed by incubation of the slide cultures at 25 degrees C in the dark for 4 weeks. Clypeate sporodochia consisting of ampulliform, compressed, phialidic conidiogenous cells produced curved, hyaline, one-celled conidia with setulae at one or both ends. Initial treatment with fluconazole for 7 days was not effective, and cultures were positive after treatment. Treatment with amphotericin B with concomitant irrigation and debridement of the affected area followed by treatment with itraconazole resulted in resolution of the infection.

Aged↗
PubMed1994

Small bowel endometriosis masquerading as regional enteritis.

A 35-year-old female presented with recurrent right lower quadrant pain, nausea, and vomiting. She was afebrile with diffuse abdominal tenderness. Plain x-ray of abdomen revealed small bowel obstruction. A barium x-ray of the small bowel showed stricture of the terminal ileum. A CT scan of the abdomen showed a 6-cm mass in right lower quadrant. She was empirically managed as having Crohn's disease. She underwent laparotomy after failure of medical management with high-dose steroids. There was ulceration and narrowing of terminal ileum. Frozen sections revealed endometriosis. Ileocecectomy was performed. Histopathology of resected specimen confirmed the diagnosis of endometriosis, and there was no evidence of chronic inflammatory bowel disease or neoplasia. Ileal endometriosis should be considered in the differential diagnosis of Crohn's disease in menstruating females presenting with perimenstrual symptoms.

Adult↗
PubMed1994

Hepatic vein obstruction due to Swan-Ganz catheter placement.

Complications from Swan-Ganz catheters during insertion, long-term placement, or removal have been known since its development. I describe the unusual presentation of a pacing Swan-Ganz catheter mispositioned into the hepatic vein producing vascular obstruction, yet with adequate cardiac pacing.

Aged↗
PubMed1992

Natural family planning.

Natural family planning includes the calendar (rhythm), basal body temperature, ovulation (mucus), and sympto-thermal methods. Reliability of such methods often is underestimated, but effectiveness of various methods has been reported. Correct understanding and use of proper techniques, primarily abstinence during fertile periods, is imperative for effectiveness. New methods being studied may heighten awareness of fertile times and shorten required periods of abstinence or use of back-up methods.

Adolescent↗
PubMed1990

Use of a camp setting to provide medical information to siblings of pediatric cancer patients.

It has been reported that siblings of children with cancer often lack information and understanding about their brother's or sister's disease and treatment. The purpose of this paper is twofold: (1) to describe a camping program for siblings, which was designed, in part, to provide these children with age-appropriate medical information; and (2) to report the results of a study which examined how this intervention influenced siblings' knowledge and understanding of their brother's or sister's disease. Ninety siblings between the ages of 6 and 17 who completed a pre/post camp medical information questionnaire participated in this investigation. The results revealed that younger (6- to 11-year-old) siblings attending camp for at least the second time and older (12- to 17-year-old) siblings attending camp for the first time experienced significant (p less than .05) improvement in their overall knowledge and understanding of their brother's or sister's cancer. The results also revealed positive changes in the desired direction with respect to siblings' fear or their friends' fear about catching their brother's or sister's cancer. The results of this study provide a conceptual model for other pediatric cancer facilities engaged in developing intervention programs for siblings.

Adolescent↗
PubMed1989

Cohesion, alliance and outcome in group psychotherapy.

Cohesiveness has been viewed as the group psychotherapy equivalent of the therapeutic alliance in individual treatment. Although researchers have attempted to study the concept of cohesion in group treatment, understanding of this so-called "curative" group factor remains quite primitive. In this study of 12 time-limited psychotherapy groups, with a total of 90 nonpsychotic outpatients, we explore the relationships between cohesion, alliance and treatment outcome. Our cohesion measure is a new instrument, the Harvard Community Health Plan Group Cohesiveness Scale, developed for use with group therapy videotapes. To measure alliance we have modified the Penn Helping Alliance Scale (Group Alliance Scale) to be scored from videotapes of group sessions. Both of these instruments use trained observers to make ratings for the group-as-a-whole. The outcome battery for patients in these groups included a widely varied set of measures, enabling us to view change from a number of perspectives. Our findings indicate that cohesion and alliance as measured here are related concepts. We also find that both cohesion and alliance appear to have strong relationships with improved self-esteem and reduced symptomatology for patients in these groups. In addition, it appears that outcome is most related to cohesion in the first 30 minutes of a group session. Implications of these and other findings are discussed.

Adult↗
PubMed1987

Structural characterization of peptides derived from prosomatostatins I and II isolated from the pancreatic islets of two species of teleostean fish: the daddy sculpin and the flounder.

The primary structures of three peptides from extracts from the pancreatic islets of the daddy sculpin (Cottus scorpius) and three analogous peptides from the islets of the flounder (Platichthys flesus), two species of teleostean fish, have been determined by automated Edman degradation. The structures of the flounder peptides were confirmed by fast-atom bombardment mass spectrometry. The peptides show strong homology to residues (49-60), (63-96) and (98-125) of the predicted sequence of preprosomatostatin II from the anglerfish (Lophius americanus). The amino acid sequences of the peptides suggest that, in the sculpin, prosomatostatin II is cleaved at a dibasic amino acid residue processing site (corresponding to Lys61-Arg62 in anglerfish preprosomatostatin II). The resulting fragments are further cleaved at monobasic residue processing sites (corresponding to Arg48 and Arg97 in anglerfish preprosomatostatin II). In the flounder the same dibasic residue processing site is utilised but cleavage at different monobasic sites takes place (corresponding to Arg50 and Arg97 in anglerfish preprosomatostatin II). A peptide identical to mammalian somatostatin-14 was also isolated from the islets of both species and is presumed to represent a cleavage product of prosomatostatin I.

Amino Acid Sequence↗