The morphology of the pecten oculi of the ostrich, Struthio camelus.

The pecten oculi is a structure peculiar to the avian eye. Three morphological types of pecten oculi are recognized: conical type, vaned type and pleated type. The pleated type has been well studied. However, there exists only scanty data on the morphology of the latter two types of pectens. The structure of the vaned type of pecten of the ostrich, Struthio camelus was investigated with light and electron microscope. The pecten of this species consists of a vertical primary lamella that arises from the optic disc and supports 16-19 laterally located secondary lamellae, which run from the base and confluence at the apex. Some of the secondary lamellae give rise to 2 or 3 tertiary lamellae. The lamellae provide a wide surface, which supports 2-3 Layers of blood capillaries. Pigmentation is highest at the distal ends of the secondary and tertiary Lamella where blood capillaries are concentrated and very scanty on the primary and the proximal ends of the secondary lamella where the presence of capillaries is much reduced. In contrast to the capillaries of the pleated pecten, the endothelium of the capillaries in the pecten of the ostrich exhibits very few microvilli. These observations suggest that the morphology of the pecten of the ostrich, a flightless ratite bird is unique to the pleated pecten and is designed to meet the balance between optimal vision and large surface area for blood supply and yet ensuring it is kept firmly erect within the vitreous.

Influence of a probiotic Enterococcus faecium strain on development of the immune system of sows and piglets.

The influence of the probiotic bacterium Enterococcus faecium SF68 on the immune system and the intestinal colonization of pigs were determined in a feeding experiment with sows and piglets. Mucosal immunity of the developing piglets was monitored by isolation and detection of intestinal lymphocyte cell populations from the proximal jejunal epithelium and the continuous Peyers patches by the use of flow cytometry. The levels of intestinal IgA in both groups of piglets were compared, as well as total IgG in the serum of sows and piglets. Feces of the sows and intestinal contents of the piglets were taken for determination of total anaerobe and coliform bacterial counts in both probiotic and control groups. Villus length and depth of the crypts were measured in the jejunum of sacrificed piglets to monitor the development of the intestinal mucosal surface amplification. Total serum IgG of the sows appeared to be unaffected. Piglets of both groups showed similar IgG levels up to 5 weeks after birth with a slight tendency toward lower values in the probiotic group. At an age of 8 weeks the total IgG levels of the probiotic animals were significantly lower (p<0.01). No differences were observed in the populations of CD4+ and CD8+ T cells in the Peyers patches. However, the levels of cytotoxic T cells (CD8+) in the jejunal epithelium of piglets of the probiotic group were significantly reduced. The depth of the jejunal crypts and length of the villi were similar in both groups, suggesting the relative T-cell population differences were not due to alterations in the epithelial cell numbers. The total anaerobe and coliform bacterial populations were not significantly affected by the probiotic treatment, either in sows or in the piglets. However, a remarkable decline in the frequency of beta-haemolytic and O141 serovars of Escherichia coli was observed in the intestinal contents of probiotic piglets, suggesting an explanation for the reduction in cytotoxic T-cell populations.

Morphology of the small intestine of weaned piglets and a novel method for morphometric evaluation.

The intestinal morphology of 7-week-old pigs was investigated by light (LM) and scanning electron microscopy (SEM). The piglets were fed either a semisynthetic or a cereal-based diet. The shapes of the intestinal villi and crypts of the duodenum, jejunum and ileum were examined. The villi were predominantly tongue-shaped. In the duodenum they were also ridged, branched and folded, and in the jejunum they were also leaf-like and ridged. At places with lymph follicles, the surface of the ileum was rugged with meandering fold-like villi. The crypts of the three segments of the small intestine were mainly coiled and sometimes branched. A novel morphometric evaluation method was introduced using the enlargement factors of each villus and crypt surface. The enlargement factor for the villus surface of the duodenum, jejunum and ileum was 3.13, 3.72 and 2.71, respectively. The factor for the crypt surface of the duodenum, jejunum and ileum was 9.07, 8.94 and 6.53, respectively. Furthermore, the relative proliferation rate and the epithelial renewal index were calculated for the first time. The relative proliferation rate of the duodenum, jejunum and ileum was 32.88, 34.78 and 50.77 proliferations per mm crypt perimeter, respectively. The diets consumed had an influence on the epithelial renewal index being higher for piglets fed the cereal-based diets.

Stressful life events and impulsiveness in failed suicide.

The relationship of recent stressful life events with impulsiveness in triggering suicide attempts and how impulsiveness changes from one suicide attempt to another is unclear. This study used structured-interview tools and standardized measurements to examine the relationship between life stress and impulsiveness in a sample of patients who required hospitalization for a medically serious suicide attempt. After controlling for potentially confounding variables, the number of disrupted interpersonal relationships in the preceding year was a significant predictor of the impulsiveness of the suicide attempt, with three or more losses (but not other life stresses) associated with less impulsive attempts (T = 2.4, p = .02). Female gender (T = -1.98, p = .05) and lifetime DMS-III-R diagnoses (T = -2.45, p = .02) were significantly associated with more impulsive attempts. In 55 patients with at least two suicide attempts, impulsiveness, lethal intent, and communication of intent were significantly greater for the present compared to the prior attempt (p = 0.000). Certain stressful life events, gender, and total lifetime DSM-III-R diagnoses are associated with impulsiveness of failed suicide attempts; yet, impulsiveness is not necessarily consistent from one suicide attempt to another. This evidence supports and amplifies a stress-diathesis model of suicide behavior. Accordingly, efforts to increase personal resilience in individuals who have "failed suicide" may be more effective at preventing suicide morbidity than simple stress-reduction measures alone.

Safety and efficacy of low anterior resection for rectal cancer: 681 consecutive cases from a specialty service.

OBJECTIVE: To determine perioperative morbidity, survival, and local failure rates in a large group of consecutive patients with rectal cancer undergoing low anterior resection by multiple surgeons on a specialty service. The primary objective was to assess the surgical complications associated with preoperative radiation sequencing. SUMMARY BACKGROUND DATA: The goals in the treatment of rectal cancer are cure, local control, and preservation of sphincter, sexual, and bladder function. Surgical resection using sharp perimesorectal dissection is important for achieving these goals. The complications and mortality rate of this surgical strategy, particularly in the setting of preoperative chemoradiation, have not been well defined. METHODS: There were 1233 patients with primary rectal cancer treated at the authors' cancer center from 1987 to 1995. Of these, 681 underwent low anterior resection and/or coloanal anastomosis for primary rectal cancer. The surgical technique used the principles of sharp perimesorectal excision. Morbidity and mortality rates were compared between patients receiving preoperative chemoradiation (Preop RT, n = 150) and those not receiving preoperative chemoradiation (No Preop RT, n = 531). Recurrence and survival data were determined in patients undergoing curative resection (n = 583, 86%) among three groups of patients: those receiving Preop RT (n = 131), those receiving postoperative chemoradiation (Postop RT, n = 110), and those receiving no radiation therapy (No RT, n = 342). RESULTS: The perioperative mortality rate was 0.6% (4/681). Postoperative complications occurred in 22% (153/681). The operative time, estimated blood loss, and rate of pelvic abscess formation without associated leak were higher in the Preop RT group than the No Preop RT group. However, the overall complication rate, rate of wound infection, anastomotic leak, and length of hospital stay were no different between Preop RT and No Preop RT patients. With a median follow-up of 45.6 months, the overall actuarial 5-year recurrence rate for patients undergoing curative resection (n = 583) was 19%, with 4% having local recurrence only, 12% having distant recurrence, and 3% having both local and distant recurrence, for an overall local recurrence rate of 7%. The actuarial 5-year overall survival rate was 81%; the disease-free survival rate was 75% and the local recurrence rate was 10%. The overall survival rate was similar between Preop RT (85%), Postop RT (72%), and No RT (83%) patients (p = 0.10), whereas the disease-free survival rate was significantly worse for Postop RT (65%) patients compared with Preop RT (79%) and No RT (77%) patients (p = 0.04). CONCLUSION: The use of preoperative chemoradiation results in increased operative time, blood loss, and pelvic abscess formation but does not increase the rate of anastomotic leaks or the length of hospital stay after low anterior resection for rectal cancer. The 5-year actuarial overall survival rate for patients undergoing curative resection exceeded 80%, with a local recurrence rate of 10%.

A scanning electron microscope study of the luminal surface specializations in the blood vessels of the pecten oculi in a diurnal bird, the black kite (Milvus migrans).

The luminal surface of the pecten oculi of the black kite (Milvus migrans), a diurnally active bird of prey, was examined by scanning electron microscopy. In this species the blood vessels are generally of two types, the small-calibre capillaries and the large-calibre afferent and efferent vessels. The luminal surface of the efferent blood vessels possesses a few low microplicae. Conversely, the luminal surface of the afferent blood vessels is characteristically smooth except at the cell junctions and at the point of entry into the capillaries. The cells junctions are marked by low ragged ridges while the luminal surface is studded with low sparse pleiomorphic microprojections at the point of capillary emergence. The luminal surface of the blood capillaries is characterised by a labyrinth of closely disposed microplicae that projects into the lumen. These microplicae show no particular orientation with respect to either the longitudinal or transverse axis of the capillary. Instead, they are diffusely orientated. It is conjectured that such a heterogeneous design of the endothelium in the blood vessels of the pecten oculi has developed in order to augment the role of the pecten in the transport of nutrients to the avascular neural retina by an energy saving diffusion process. The process through which the design of the microfolds affects haemodynamics and their putatite role in facilitating the delivery of nutrients are discussed in the perspective of the available data.

Surface specialization of the capillary endothelium in the pecten oculi of the chicken, and their overt roles in pectineal haemodynamics and nutrient transfer to the inner neural retina.

The structure of the capillary endothelium in the pecten oculi of the domestic fowl was investigated by scanning and transmission electron microscopy. Scanning electron microscopy results demonstrated the existence of a vast array of irregular microplicae that projected from the luminal surface of the capillary endothelium. In between these microplicae were numerous crevices. The microplicae were closely packed and showed no preferred orientation regarding either the longitudinal or transverse plane of the capillaries. Transmission electron microscopy revealed the section profiles of the microplicae: their tortuity, branching, interdigitations and the magnitude of the crevices contained. The endothelial cytoplasm exhibited a few mitochondria and micropinocytotic vesicles. The apparent set-up of the luminal plasmalemmal infoldings seemed to be designed for effecting impedance to the pectineal blood flow and thereby facilitating passive permeation of blood-borne nutrients to the inner neural retina. The reasons of such passive transport operation mediated by the endothelial microplicae of the avian pecten oculi are discussed in the perspective of the existing literature.

Does continuity of care increase HMO patients' satisfaction with physician performance?

BACKGROUND: This study describes the relation between patient satisfaction with physician performance and seeing one's "own doctor" for a recent office visit. METHODS: A cross-sectional, randomized, computer-assisted telephone interview survey was performed at an urban health maintenance organization; 1146 responses were analyzed. RESULTS: Patients seeing their own physicians were significantly more satisfied than patients seeing another physician, even after controlling for effects of patient age, sex, reason for visit, clinic attended, satisfaction with appointment making, and interval between scheduling and making the visit. The interaction between getting one's choice of provider and seeing one's own physician was a significant predictor of satisfaction (P = 0.003). Among patients who got their choice of provider, seeing one's own physician had a more significant effect on satisfaction than seeing any other physician (P = 0.0009 compared with P = 0.04). Patients who did not receive their choice of provider but who did see their own physician had the highest satisfaction scores (P = 0.007). CONCLUSION: To increase patient satisfaction with physician performance, health maintenance organizations should ensure that patients see their "own doctor" whenever possible for routine office visits.

HMO family physicians: men and women differ in their work.

OBJECTIVE: The goal was to identify differences in the type of work and amount of work performed by male and female family HMO physicians. DESIGN: Data were collected by self-administered physician surveys, retrospective analysis of encounter forms, ambulatory care group (ACG) analysis of physicians' patient panels, and participant observation. SETTING: A large HMO-based clinical facility. PARTICIPANTS. Family practitioners (n = 21) at one HMO clinic. MAIN OUTCOME MEASURES: Measures included patient encounters/day, self-assessed and encounter-form-based workload, ambulatory care group panel evaluation and qualitative observation of practice patterns and team functioning. RESULTS: These data show that the kind of work male and female physicians did at this site differed, when compared on the basis of encounter-form-based diagnoses, ambulatory care group panel assessments and participant observation. However, the amount of work performed by each gender did not appear to different when evaluated by age-sex-adjusted panel size, patient encounters per unit time, a subjective magnitude estimation workload questionnaire and an encounter-form-based workload assessment. CONCLUSION: In this study, multiple measures for evaluating physician workload revealed distinct differences in the kind of clinical work performed by male and female HMO family physicians. These findings have implications for clinicians, managers, planners, researchers and educators.

The role of physicians' personal knowledge of the patient in clinical practice.

BACKGROUND: Primary care physicians' personal knowledge of their established patients has not been investigated systematically, and its role in clinical practice has not been characterized empirically. METHODS: A qualitative study used an iterative, grounded theory method for thematic analysis of transcribed, semistructured long interviews. Subjects were family physicians in stable employment and in continuous clinical practice for at least 2 years at a staff-model health maintenance organization. RESULTS: Personal knowledge of the patient clearly influenced the use of time in the examination room, the recognition of changes in baseline status, and the ability to verbalize medical information in terms that have unique meaning for particular patients. Personal knowledge fostered a sense of predictability in personal interactions; facilitated the creation of trust; served as an organizing scheme for data collection, recall, and interpretation; counterbalanced impersonal professional principles such as compulsiveness, duty, and responsibility; shaped ability to communicate effectively about issues related to quality of life and functional status; influenced choices of consultants; but also had the potential to interfere with diagnosis or with patient presentation of new information. CONCLUSIONS: Personal knowledge of patients was an important influence on physicians' daily clinical practice in this setting.

A scanning electron microscope study of the pecten oculi of the black kite (Milvus migrans): possible involvement of melanosomes in protecting the pecten against damage by ultraviolet light.

The pecten oculi of the black kite (Milvus migrans), a diurnally active bird of prey, has been examined by scanning electron microscopy. In this species the pecten consists of 12 highly vascularised pleats, held together apically by a heavily pigmented 'bridge' and projects freely into the vitreous body in the ventral part of the eye cup. Ascending and descending blood vessels of varying calibre, together with a profuse network of capillaries, essentially constitute the vascular framework of the pecten. A distinct distribution of melanosomes is discernible on the pecten, the concentration being highest at its apical end, moderate at the crest of the pleats and least at the basal and lateral margins. Overlying and within the vascular network, a close association between blood vessels and melanocytes is evident. It is conjectured that such an association may have evolved to augment the structural reinforcement of this nutritive organ in order to keep it firmly erectile within the gel-like vitreous. Such erectility may be an essential prerequisite for its optimal functioning, as well as in its overt use as a protective shield against the effects of ultraviolet light, which otherwise might lead to damage of the pectineal vessels.

The personal knowledge of family physicians for their patients.

The physician-patient relationship has always been of interest to family physicians. This paper describes a component of the physician-patient relationship in family medicine, originally identified by Michael Balint, that operates parallel to and in conjunction with the biopsychosocial model: the family physician's personal knowledge of patients. The physician's personal knowledge of patients is a personal information network about particular patients who the physician has cared for over a series of encounters spanning several years. It is a detailed portrait painted with layers of fact, intuition, and experience and is comprised of a mix of clinical art, science, psychodynamics, and ethics. It may be factual, intuitive, or contain components of countertransference; it differs from Kleinman's concept of explanatory model in that it belongs to the physician and is employed for the benefit of the patient. It is neither paternalistic nor static. The family physician's personal knowledge for his or her patients is a seldom-measured but common component of the process of making medical, ethical, and pragmatic patient care decisions. The presence of this knowledge and its skillful use may mark one difference between novice and seasoned clinicians. Qualitative methods are most appropriate for exploring the breadth and depth of this concept, while quantitative methods are useful for studying its implications for clinical decision making and quality of care in family practice.

The mating pair formation system of plasmid RP4 defined by RSF1010 mobilization and donor-specific phage propagation.

Transfer functions of the conjugative plasmid RP4 (IncP alpha) are distributed among distinct regions of the genome, designated Tra1 and Tra2. By deletion analyses, we determined the limits of the Tra1 region, essential for intraspecific Escherichia coli matings. The Tra1 core region encompasses approximately 5.8 kb, including the genes traF, -G, -H, -I, -J, and -K as well as the origin of transfer. The traM gene product, however, is not absolutely required for conjugation but significantly increases transfer efficiency. To determine the transfer phenotype of genes encoded by the Tra2 core region, we generated a series of defined Tra2 mutants. This revealed that at least trbB, -C, -E, -G, and -L are essential for RP4 conjugation. To classify these transfer functions as components of the DNA transfer and replication (Dtr) or of the mating pair formation (Mpf) system, we analyzed the corresponding derivatives with respect to mobilization of IncQ plasmids and donor-specific phage propagation. We found that all of the Tra2 genes listed above and the traG and traF genes of Tra1 are required for RSF1010 mobilization. Expression of traF from Tra1 in conjunction with the Tra2 core was sufficient for phage propagation. This implies that the TraG protein is not directly involved in pilus formation and potentially connects the relaxosome with proteins enabling the membrane passage of the DNA. The proposed roles of the RP4 transfer gene products are discussed in the context of virulence functions encoded by the evolutionarily related Ti T-DNA transfer system of agrobacteria.

[The conjunctival epithelium of dogs. Light and electron microscopic investigations]. / Das Konjunktivalepithel des Hundes. Licht- und elektronenmikroskopische Untersuchungen.

The conjunctiva of the dog has a smooth surface on the inside of the upper and lower lid and of the bulbus oculi. In these areas the conjunctiva is covered by a stratified squamous epithelium, the polygonal surface cells of which have microvilli and microplicae which are different in number and show a great variety of shapes. In the passage towards the fornix conjunctivae a stratified cuboidal epithelium is to be discerned. In the fornix itself, the conjunctiva is arranged in small folds which are protruded by goblet cells and the openings of lacrimal glands. Here a stratified cuboidal or columnar epithelium can be observed which at the electron microscopic level shows in all epithelial layers--mostly however in the stratum superficiale--morphological signs of enhanced metabolic activities. The bulbar surface of the third eyelid which is covered by a stratified squamous epithelium has a three-dimensional moulded pattern of pads and grooves. The structure of the conjunctival epithelium to some extend is age dependent.

Patient sex role and preference for a male or female physician.

A study was undertaken to test whether a patient's sex role, as measured by the Bem Sex Role Inventory, is associated with preference for a male or female physician. One hundred ninety-three patients completed a physician preference survey and the Bem Sex Role Inventory. Thirty-six percent of patients preferred a physician of a specific sex. For women, sex role was associated with preference for a female physician (chi 2 = 16.14, P less than .01). Women with an androgynous sex role who gave a preference always chose a female physician; three fourths of women with an undifferentiated sex role who gave a preference always chose a female physician. Regardless of sex role, men who gave a preference always chose a male physician. For women, these findings support the hypothesis that sex role is associated with preference for a female physician.

Development of gastrin-and somatostatin-containing cells in the pyloric gland region of the bovine abomasum.

The ontogeny of gastrin- and somatostatin-containing cells in the pyloric gland region of the abomasum was studied in bovine fetuses, newborns and adults, using immunohistochemical techniques. A clear-cut developmental increase in the two kinds of endocrine cells could not be observed. The region of the lesser curvature displays more D and G cells than the greater curvature. Cells of both open and closed types are found from the earliest stages examined and continue to be present throughout the complete differentiation of the pyloric mucosa.