Higher sociability leads to lower reproductive success in female kangaroos.

In social mammals, social integration is generally assumed to improve females' reproductive success. Most species demonstrating this relationship exhibit complex forms of social bonds and interactions. However, female eastern grey kangaroos (Macropus giganteus) exhibit differentiated social relationships, yet do not appear to cooperate directly. It is unclear what the fitness consequences of such sociability could be in species that do not exhibit obvious forms of cooperation. Using 4 years of life history, spatial and social data from a wild population of approximately 200 individually recognizable female eastern grey kangaroos, we tested whether higher levels of sociability are associated with greater reproductive success. Contrary to expectations, we found that the size of a female's social network, her numbers of preferential associations with other females and her group sizes all negatively influenced her reproductive success. These factors influenced the survival of dependent young that had left the pouch rather than those that were still in the pouch. We also show that primiparous females (first-time breeders) were less likely to have surviving young. Our findings suggest that social bonds are not always beneficial for reproductive success in group-living species, and that female kangaroos may experience trade-offs between successfully rearing young and maintaining affiliative relationships.

Evidence for scent marking in vervet monkeys?

We used data from two troops of free-ranging vervet monkeys (Chlorocebus aethiops) to assess the proposition that the conspicuous chest rubbing observed in this species constitutes scent-marking behavior. Our data indicate that chest-rubbing behavior is associated with higher-ranking males who are more likely to do so during the breeding season in areas where territorial encounters occur. We found no indication that chest rubbing was triggered directly by encounters between troops. We conclude that these data, in conjunction with reports of chest rubbing from other Old World monkeys, are sufficiently suggestive of scent marking to warrant further, directed research and support the suspicion that olfactory cues remain important to catarrhines in a number of domains.

Measurement of conformational changes in the structure of transglutaminase on binding calcium ions using optical evanescent dual polarisation interferometry.

The conformational changes occurring when the protein transglutaminase binds calcium ions have been studied using the optical evanescent technique of dual polarization interferometry (DPI) implemented via a dual slab waveguide structure. Immobilized transglutaminase layers of 4-5 nm in thickness were obtained, which when challenged with calcium ions underwent a contraction of approximately 0.5 nm (depending on the concentration of calcium) and an increase in refractive index of approximately 1 x 10-2. The affinity constant for the calcium binding was found to be in the range of 0.95 +/- 0.2 mM. The results reported are in good agreement with those found in the literature obtained by other techniques. It has also been shown that the structural changes occurring during the binding event are considerably larger than the mass changes that take place; thus, DPI offers a potentially valuable method to study real-time structural changes occurring to proteins when they bind metal ions.

Quantifying the effects of melittin on liposomes.

Melittin, the soluble peptide of bee venom, has been demonstrated to induce lysis of phospholipid liposomes. We have investigated the dependence of the lytic activity of melittin on lipid composition. The lysis of liposomes, measured by following their mass and dimensions when immobilised on a solid substrate, was close to zero when the negatively charged lipids phosphatidyl glycerol or phosphatidyl serine were used as the phospholipid component of the liposome. Whilst there was significant binding of melittin to the liposomes, there was little net change in their diameter with melittin binding reversed upon salt injection. For the zwitterionic phosphatidyl choline the lytic ability of melittin is dependent on the degree of acyl chain unsaturation, with melittin able to induce lysis of liposomes in the liquid crystalline state, whilst those in the gel state showed strong resistance to lysis. By directly measuring the dimensions and mass changes of liposomes on exposure to melittin using Dual Polarisation Interferometry, rather than following the florescence of entrapped dyes we attained further information about the initial stages of melittin binding to liposomes.

Rhabdomyolysis associated with the combined use of hydroxymethylglutaryl-coenzyme A reductase inhibitors with gemfibrozil and macrolide antibiotics.

The hydroxymethylglutaryl-coenzyme A reductase inhibitors (HMG-CoAs) are one of the most significant causes of medication induced rhabdomyolysis. The development of rhabdomyolysis is increased when the HMG-CoAs are used concurrently with certain other medications, specifically gemfibrozil and macrolide antibiotics. In this report, we describe a patient with rhabdomyolysis from the combined use of lovastatin, gemfibrozil, and clarithromycin and review the relevant literature.

Angiocentric T-cell lymphoma presenting as lethal midline granuloma.

BACKGROUND: Lethal midline granuloma (LMG) is a rare condition characterized by rapidly progressive midfacial destruction. Most LMG cases are angiocentric T-cell lymphomas and an association with Epstein-Barr virus (EBV) has been reported. Cutaneous involvement is poorly described and the prognosis not well documented. METHODS: We report a case of angiocentric T-cell lymphoma of the palate that presented as LMG with concurrent discrete skin lesions composed of two distinct morphologic appearances: indurated nodules and annular plaques. The English language literature for LMG-type angiocentric T-cell lymphoma is reviewed and a survival analysis of 58 cases with follow-up data (including our own case) is performed. RESULTS: The 1- and 5-year survival rates were 45% +/- 7% and 22% +/- 9%, respectively. Poor survival was associated with advanced age and stage. EBV DNA was detected in 16 out of 21 reported cases in which it was sought (including our case). CONCLUSIONS: We present photographic documentation of a broader spectrum of cutaneous lesions in the LMG-type angiocentric T-cell lymphoma than has previously been described, and have confirmed the association with EBV. The prognosis is poor. Aggressive therapy such as bone marrow transplantation should be considered early in the course.

The hypercoagulability of polycythemia vera.

Thrombosis is the most common cause of death in patients with this myeloproliferative syndrome. Phlebotomy, hydroxyurea, and antiplatelet agents are the mainstays of therapy but may not stave off a lethal embolism.

Elevated prostate markers in metastatic small cell carcinoma of unknown primary.

Numerous ectopic hormones and markers have been described in small cell carcinoma of the lung as well as in extrapulmonary small cell carcinomas. The authors report a case of a patient with metastatic small cell carcinoma of unknown primary who had very high prostatic acid phosphatase (PAP) and prostatic specific antigen (PSA) levels. Results of multiple prostate examinations, as well as blind biopsies, were normal. His course was significantly longer than that of the usual patient with extensive small cell carcinoma. At autopsy the prostate showed only mild benign prostatic hypertrophy. There are no previous reports in the literature of abnormal prostate markers in small cell carcinomas. Physicians should be aware of the increasing complexity and the unusual biologic markers associated with neuroendocrine carcinomas. In some of these cases, the tumors ability to produce an ectopic product may portend an improved prognosis.

Radiocontrast-associated renal dysfunction: incidence and risk factors.

Contrast-induced nephropathy is a potentially serious untoward reaction to radiologic contrast media. The incidence of this nephropathy and the predisposing conditions are not well established, possibly because of methodologic differences between studies. We evaluated the incidence of contrast-induced nephropathy after femoral arteriography in 394 patients by using multiple definitions (different increases in serum creatinine or blood urea nitrogen levels at various times). When an increase in the level of serum creatinine of greater than 0.3 mg/dl and greater than 20% on day 1, 2, or 3 and on day 5, 6, or 7 was used to define the disorder, the incidence in our group of patients was 10% for nonazotemic patients vs 30% for azotemic patients (p less than .001); 2% for nondiabetic, nonazotemic patients vs 16% for diabetic, nonazotemic patients (p = .003); and 38% for patients who were both diabetic and azotemic vs 16% for diabetic, nonazotemic patients (p = .022). Baseline renal insufficiency and diabetes mellitus (especially when insulin dependent) were significant predisposing factors. The effects of dehydration and increased volume of contrast medium on the incidence of contrast-induced nephropathy were not clear; the age and sex of the patient were not important risk factors. The incidence of contrast-induced nephropathy depends on the definition used. Although contrast-induced nephropathy may develop in any patient, diabetes, renal insufficiency, and, possibly, dehydration and dose of contrast medium are risk factors.

Radiocontrast-associated renal dysfunction: a comparison of lower-osmolality and conventional high-osmolality contrast media.

Nephropathy is an established untoward event associated with intravascular administration of conventional high-osmolality contrast media (HOM). It has not been shown previously that lower-osmolality contrast media (LOM) are less nephrotoxic in a clinical setting. We evaluate the ability to replace HOM with LOM (in lower-extremity angiography) to reduce the incidence of nephropathy. We use multiple definitions for contrast-induced nephropathy (six different magnitudes of rise of serum levels of creatinine or blood urea nitrogen in various periods). The incidences of nephrotoxic effects with LOM vs HOM in patients with presumed risk factors, including preexisting renal insufficiency and diabetes, are evaluated also. When all patients are considered, the incidence of contrast-induced nephropathy for LOM vs HOM (defined as an increase in serum creatinine level greater than 0.3 mg/dl and greater than 20% on day 1, 2, or 3 and on day 5, 6, or 7, is 7% vs 26% (p = .001). When only patients with preangiography azotemia are considered, the incidence of contrast-induced nephropathy for LOM vs HOM is 10% vs 41% (p = .017); for diabetic patients, regardless of preangiography creatinine level, the incidence is 10% vs 31% (p = .012). Although contrast-induced nephropathy may develop even in a patient with no risk factors who receives LOM, LOM is associated with a decreased incidence of this condition, to various degrees, depending on the presence of risk factors.

Isolated left carotid artery in CHARGE association: diagnosis and repair.

Isolation of the left carotid artery is extremely rare. We report a case of isolation of the left carotid artery with CHARGE association. Aortic arch abnormalities should be looked for in all children with CHARGE association. The technique of repair involved implantation of the isolated left carotid artery to the ascending aorta.

5-Fluorouracil-associated cardiotoxicity.

Cardiotoxicity manifested as myocardial ischemia is not generally recognized as a side effect of 5-fluorouracil. However, there have been at least 35 cases reported since 1975. In only one of these cases was a somewhat detailed evaluation done to rule out underlying coronary disease. The case reported here of 5-FU cardiotoxicity included an extensive cardiac evaluation to rule out underlying coronary disease and to assess spasm. The literature on 5-FU cardiotoxicity is also reviewed, and its possible mechanisms are analyzed.