Differential reproductive plasticity under thermal variability in a freshwater fish (Danio rerio).

Human-driven increases in global mean temperatures are associated with concomitant increases in thermal variability. Yet, few studies have explored the impacts of thermal variability on fitness-related traits, limiting our ability to predict how organisms will respond to dynamic thermal changes. Among the myriad organismal responses to thermal variability, one of the most proximate to fitness-and, thus, a population's ability to persist-is reproduction. Here, we examine how a model freshwater fish (Danio rerio) responds to diel thermal fluctuations that span the species's viable developmental range of temperatures. We specifically investigate reproductive performance metrics including spawning success, fecundity, egg provisioning and sperm concentration. Notably, we apply thermal variability treatments during two ontogenetic timepoints to disentangle the relative effects of developmental plasticity and reversible acclimation. We found evidence of direct, negative effects of thermal variability during later ontogenetic stages on reproductive performance metrics. We also found complex interactive effects of early and late-life exposure to thermal variability, with evidence of beneficial acclimation of spawning success and modification of the relationship between fecundity and egg provisioning. Our findings illuminate the plastic life-history modifications that fish may undergo as their thermal environments become increasingly variable.

The family resemblance metaphor: some unfinished business of interpretive inquiry.

The rapidly expanding discipline of interpretive inquiry, especially in its narrative analysis form, has not been fully cognizant of certain crucial epistemological and methodological assumptions that form the ultimate basis of its purpose. Even after abandoning traditional positivist views, the related disciplines within the human sciences that are engaged in interpretive inquiry have still not discovered the core implicit assumptions that militate against a full acceptance of this form of inquiry. This article outlines the locus of these implicit assumptions and then argues that the legitimacy of these enterprises must be grounded in a well-known but heretofore undiscovered perspective, namely, Wittgenstein's notion of a family resemblance. It is argued that this metaphoric phrase is the key to unlocking the real and unique nature of narrative analysis.

Hearing discordant voices: some notes on using Bayes's theorem in interpretive inquiry.

The focus of these brief comments is to argue that Bayes's theorem may have conceptual and pedagogical applications for qualitative analysis. We suggest that the theorem is a salient alternative voice for the development of sensitizing concepts. It is also proposed that the theorem is a useful heuristic for raising deep-structure issues such as the nature of qualitative evidence and how such evidence becomes confirming for a given claim.

Pharmacologic considerations in the dental management of the patient with disorders of the renal system.

As reviewed in this article, the patient with ESRD presents a number of unique management challenges. A rapidly increasing number of patients are receiving renal transplants and undergoing dialysis, making it necessary for the dental practitioner to have a thorough understanding of the special treatment considerations that arise. Conservative medical management is designed to slow the progression of the disease and ameliorate the clinical consequences. Dialysis and transplantation provide renal replacement to sustain life and allow for the medical and social rehabilitation of the patient. When considering transplantation, oral examination is an essential part of the preoperative evaluation. Elimination of pathologic entities and restoring patient function are essential before the transplant and the immunosuppressive drug regimen. Any oral symptom or sign of infection must be examined immediately and treated aggressively in an immunosuppressed transplant recipient. Patients receiving hemodialysis and those with transplants should be considered for antimicrobial prophylaxis before dental treatment that induces bleeding to protect the function and patency of the vascular access site and the transplant. Drug therapy may need to be adjusted, depending on the degree of chronic renal failure, the patient's dialysis schedule, or the presence of a transplant. Therefore, the dentist must be familiar with the complexity of this interesting patient population and pay particular attention when prescribing and using various medications.

Where the kidney is concerned, how much mannitol is too much?

OBJECTIVE: To report a case of mannitol-induced acute renal failure (ARF). CASE SUMMARY: A 31-year-old woman who had been on long-term warfarin therapy for atrial fibrillation was admitted to the hospital with hemoptysis. Following reversal of her anticoagulation, she had a tonic-clonic seizure nine days after admission. An emergency computed tomography scan revealed cerebral edema, which was initially treated with hyperventilation and steroids. Two days later, a repeat scan showed progression of the cerebral edema with midline shift. Mannitol 550 g was infused over the next 28 hours, precipitating ARF. Despite prompt hemodialysis to reverse the renal failure, the patient died. This case of apparent mannitol-induced ARF illustrates several pathophysiologic effects of this agent. DISCUSSION: Case reports in the literature discussing mannitol-induced ARF are reviewed and compared. A relationship between dose and ARF and its reversal with hemodialysis is postulated. CONCLUSIONS: It is likely that sufficient doses of mannitol may lead to ARF. Limitation of dose may prevent and treatment with hemodialysis may reverse ARF in these instances.

Renal vasodilatory response to intravenous glycine in the aging rat kidney.

Studies were performed in the awake, chronically catheterized male Sprague-Dawley rat to investigate renal hemodynamics in the baseline state and also in response to a large intravenous (IV) amino acid (glycine) load. Studies were performed in young adult rats (age 3 to 4 months), old rats (age 18 months), and senescent rats (age 22 to 24 months). Histologic evaluation of the kidney permitted a correlation between structural and functional changes with aging. Histology showed progressive glomerular damage (sclerosis) with aging. In 18-month-old rats, the glomerular filtration rate (GFR) was normal, which, considering the level of glomerular injury (only 64% normal glomeruli), must indicate heterogeneity of glomerular function, with some hyperfunctioning glomeruli. By 22 to 24 months of age (at which time approximately 50% mortality has occurred in males of this strain), GFR is substantially reduced, as is renal plasma flow rate (RPF). Severe glomerular damage was observed histologically (only 34% normal glomeruli), indicating widespread heterogeneity of glomerular function. Young adult rats displayed a substantial renal vasodilation in response to acute IV glycine infusion, which resulted in approximately 25% increases in GFR and RPF. The renal vascular responsivity to glycine was diminished at 18 months and was completely absent in 22- to 24-month-old rats. This altered renal vasodilatory response to glycine probably reflects both structural changes associated with aging and also the compensatory vasodilation of intact hyperfunctioning remnant nephrons as other nephrons are lost due to aging.

The mechanisms of proteinuria in aging rats.

Aging is associated with the appearance of a selective proteinuria which cannot be attributed to any specific underlying renal disease. The present studies were conducted in conscious, chronically catheterized young (3-4 months), non-proteinuric male rats and old (22-25 months), proteinuric males to determine the mechanism(s) of the proteinuria. Compared with young males, old proteinuric rats had increased blood pressure, reduced glomerular filtration rate (GFR) and renal plasma flow and heavy proteinuria. Fractional clearance of neutral dextran (D) and anionic dextran sulfate (DS) were both significantly increased at the 36 A molecular radius in old rats; the increase in DS fractional clearance being greater than the increase in D fractional clearance. The proteinuria of aging is therefore due to moderate increases in glomerular permeability and, more importantly, to loss of fixed glomerular polyanion. Striking glomerular morphologic changes were also evident in the old rats including thickening of the glomerular basement membrane and extensive glomerular sclerosis.

Hydrolytic enzyme activities of the nervous system.

The activities of five hydrolytic enzymes (acid and alkaline phosphatase, hexosaminidase [N-acetyl-beta-D-glucosaminidase], beta-galactosidase, and beta-glucorinidase) were measured in reconstituted homogenates of lyophilized human brain tissue and primary and metastatic tumors. The linearity of reaction, with respect to incubation time, and optimal pH of each enzyme and in tumor tissues were comparable to those in normal brain tissue. Total enzyme activities of hexosaminidase, beta-glucuronidase, and beta-galactosidase were significantly higher in tumors than in normal cerebral white matter. The ratio of hexosaminidase activity to beta-glucuronidase activity was significantly lower for metastatic than for primary tumors or normal white matter. When histological observations do not clearly establish if a brain tumor is primary or metastatic, this ratio may help. Alteration of hydrolytic enzyme activities as demonstrated here may be indicative of "ket enzymes" that are essential for maintaining the metabolic advantages of tumors.

Hydrolytic enzymes in meningiomal subtypes.

Estimation of activity of five hydrolytic enzymes was made in foru histologically different types of human meningiomas derived from surgery. The hydrolytic enzymes examined in 13 tumors included four lysosomal enzymes: beta-glucuronidase, N-acetyl-beta-D-glucosaminidase (hexosaminidase), beta-galactosidase, and acid phosphatase. The fifth enzyme studied was alkaline phosphatase. The one papillary-type meningioma examined appeared to contain generally greater activities of the lysosomal enzymes than the other tumor types. Alkaline phosphatase was decidedly greater in transitional type meningiomas. The correlation of histological types with alkaline phosphatase activity is discussed with regard to previous observations.

Health care professionals: a model for teaching the components of society-culture-personality in the delivery of care.

In recent years, the behavioral sciences have contributed tremendously tot he education of future physicians, dentists, nurses, and other health care professionals. With the inclusion of the behavioral sciences component in the National Board Examination (1972), many medical schools have revised their curricula to include sociology in the training of the future physician. However, the tremendous shortage of qualified social scientists made it difficult to meet the needs of medical schools and health programs in the country.In view of this problem, this paper will present a single conceptual model that can be used as an organizational device for teaching some basic social science concepts to health care students and to assist them in the comprehension of the impact of society-culture-personality (SCP) on the health care institution as a whole. Uses of this model have been presented elsewhere.(1,2)

A model for teaching health care professionals the components of the family.

With the inclusion of the behavioral sciences component in the National Board Examination (1972), many medical schools have revised their curricula to include sociology in the training of the future physician. In dentistry, the behavioral sciences group of the International Association for Dental Research has increased in membership over the past years. In nursing, courses such as sociology, psychology, and anthropology have already been included in the curricula of various schools. However, the tremendous shortage of qualified social scientists who are capable of relating the behavioral sciences to the health care institution makes it difficult to meet the needs of graduate and professional schools everywhere. In view of this problem, this article will present a simple conceptual model that can be used as an organizational device for teaching the components of the family in relation to the health care institution.