A prospective randomized controlled study of the effect of short coincubation of gametes during insemination on zona pellucida thickness.

A prospective, randomized study was conducted to evaluate the thickness, of zona pellucida (ZP) after brief or standard exposure of human oocytes to spermatozoa, and to determine the correlation between ZP thickness, fertilization rate and embryo quality. The mean ZP thickness 48 h after insemination was found to be significantly less in fertilized oocytes than in non-fertilized oocytes in all treated groups (13.72 +/- 3.0 microns and 15.08 +/- 2.5 microns, respectively; p < 0.007). Zona pellucida thickness correlated positively with embryo quality. Brief exposure of gametes was found to influence ZP thickness. The ZP was significantly thinner after brief and intracytoplasmic sperm injection (ICSI) exposure of oocytes to spermatozoa than after standard in vitro fertilization (IVF). The mean ZP thickness 24 and 48 h after fertilization was significantly greater in standard IVF (16.43 +/- 2.8 microns and 15.22 +/- 2.7 microns, respectively) than in either the brief exposure or ICSI groups (12.78 +/- 2.4 microns and 13.01 +/- 3.5 microns vs. 13.46 +/- 2.2 microns and 13.16 +/- 2.4 microns; p < 0.0001).

Whose evidence? Lessons from the philosophy of science and the epistemology of medicine.

OBJECTIVE: To demonstrate the inadequacies of empiricism as a scientific foundation for evidence-based approaches to psychiatry. METHOD: The principles of empiricism are reviewed in the light of developments in the philosophy of science and phenomenology. Case studies are selected from the history of physical sciences, biological science and clinical sciences (pathology, neuroscience, psychosocial science and psychopathology), paying particular attention to the role of observation in theory construction. RESULTS: The principles of empiricism, particularly its view of the nature of observation as the basis of evidence do not reflect the historical reality of scientific theorizing and practice. Science has constructed alternative models of its own activity that do justice to the complexities of its subject matter, including the world of human experience and mental illness. CONCLUSIONS: A failure to recognize both the limitations of empiricism in science and the conceptual richness of alternative formulations that accord more closely with the complexity of psychiatry's domain will result in a naïve model of science and inadequate understanding of the limitations of 'evidence' that guide the training, clinical practice and research in our profession. The consequences will be the intellectual, clinical and ethical impoverishment of psychiatry.

Multitude of ion channels in the regulation of transmitter release.

The presynaptic nerve terminal is of key importance in communication in the nervous system. Its primary role is to release transmitter quanta on the arrival of an appropriate stimulus. The structural basis of these transmitter quanta are the synaptic vesicles that fuse with the surface membrane of the nerve terminal, to release their content of neurotransmitter molecules and other vesicular components. We subdivide the control of quantal release into two major classes: the processes that take place before the fusion of the synaptic vesicle with the surface membrane (the pre-fusion control) and the processes that occur after the fusion of the vesicle (the post-fusion control). The pre-fusion control is the main determinant of transmitter release. It is achieved by a wide variety of cellular components, among them the ion channels. There are reports of several hundred different ion channel molecules at the surface membrane of the nerve terminal, that for convenience can be grouped into eight major categories. They are the voltage-dependent calcium channels, the potassium channels, the calcium-gated potassium channels, the sodium channels, the chloride channels, the non-selective channels, the ligand gated channels and the stretch-activated channels. There are several categories of intracellular channels in the mitochondria, endoplasmic reticulum and the synaptic vesicles. We speculate that the vesicle channels may be of an importance in the post-fusion control of transmitter release.

The doctor's troubled marriage.

BACKGROUND: Reports about the health of doctors have included claims of an increased risk of unhappy marital and family relationships. Recent studies cast doubt on these pessimistic conclusions but certain patterns of troubled marriages seem to exist as do certain stressors, to which doctors may be particularly susceptible. OBJECTIVE: To describe the individual and interpersonal dynamics of problematic marriages commonly encountered among medical practitioners and to review some common stressors in medical marriages in general. DISCUSSION: Three commonly encountered patterns of troubled marriages are described and the ways they develop in the context of medical training and practice. The large increase in the number of women doctors in the past 20 years has brought new challenges to women and men seeking to balance their family and professional commitments.

Diagnosis and serious mental illness.

We examine some limitations of the psychiatric diagnosis, particularly in the assessment of the seriousness of a patient's mental illness. The bureaucratic or technocratic use of the concept "serious mental illness' is contrasted with the perspective of the clinician who provides ongoing patient care. A decline in the clinical skills of psychiatrists is likely if proposed mental health reforms regulate psychiatric practice according to bureaucratic and technocratic definitions of serious mental illness rather than the realities of the clinical encounter between patient and doctor.

Working with the family: the role of values.

In this paper, we have examined that ethical aspect of working with families which stresses the relevance of values. Given that values are at the heart of both the family's and the therapists's view of the world, we see it as crucial for them to be addressed in the course of assessment and treatment. A variety of approaches have been adopted by clinicians ranging from those who regard ethics as a cornerstone of therapy to more compartmentalized positions, whereby specific sociopolitical themes like racism, poverty, and sexism are highlighted. Whatever model is preferred, the essential task is to accept that values are a necessary feature of therapeutic work and require negotiation. Failure to do so may have adverse repercussions on the therapist-family relationship, even to the point of jeopardizing therapy. Guidelines can be articulated to forestall such unfortunate consequences. We have attempted to identify these in the hope of clarifying for therapists the necessary steps they need to take to safeguard the family's interests and achieve an optimal ethical (and clinical) outcome.

Potential perils of the demonstration-consultation interview in family therapy: a case study of contextual confusion.

This article focuses on a specific aspect of consultation in contemporary family therapy, namely, problems that arise in the context of a consultation that simultaneously serves as a demonstration of a particular model of therapy. The demonstration-consultation interview is used widely in family therapy, but has received little attention in the literature. We use a case example of the apparent persistent deterioration in the clinical state of a patient following such a family interview with a visiting expert, and examine the possible contribution to the patient's deterioration that the demonstration-consultation context creates for the various participants. We offer provisional guidelines to minimize the risk of negative effects of the demonstration-consultation interview, pending empirical research into this phenomenon.

The effect of purified aminoaldehydes produced by polyamine oxidation on the development in vitro of Plasmodium falciparum in normal and glucose-6-phosphate-dehydrogenase-deficient erythrocytes.

Purified aminoaldehydes produced by polyamine oxidation were toxic to the malarial parasite, Plasmodium falciparum, cultured in human erythrocytes. There was a profound effect on young ring forms, and, during maturation, parasites became more sensitive to the aldehydes. Oxidation of the aldehydes abolished the lethal effect. The plasmodia within glucose-6-phosphate-dehydrogenase (G6PD)-deficient erythrocytes were more sensitive to mono- and di-aldehydes than were parasites in normal erythrocytes. G6PD-deficient erythrocytes were also more sensitive to pretreatment with the dialdehyde produced by the oxidation of spermine. Pretreatment prevented further invasion by the parasites.