Stability of allopurinol suspension compounded from tablets

The stability of allopurinol as an extemporaneous suspension compounded form tablets was studied. The allopurinol suspension (20 mg/mL) was prepared by incorporating pulverized 300-mg allopurinol tablets into the suspending vehicle containing sodium carboxymethylcellulose and magnesium aluminum silicate (Veegum). Lycasin (a syrup vehicle that is 75% maltilol was added to this mixture. Appropriate antioxidants, preservatives, sweeteners and flavoring agents also were used. Samples of the suspension were stored in amber-colored glass bottles at 50 deg, 60 deg, 70 deg, and 80 deg C. At various times during the 97-day study period, the concentration of allopurinol in each sample was determined by a stability-indicating high performance liquid chromatography assay procedure. At the same time, samples were inspected visually for signs of caking or settling and evaluated for redispersibility and pourability. The aqueous solubility of allopurinol as a function of temperature also was studied. It was found that the aqueous solubility of allopurinol increased with an increase in the temperature. A zero-order reaction was assumed for the suspension. The kinetics of degradation were determined and the energy of activation and shelf-life were calculated using the Arrhenius plot. During the study period all samples remained homogenous and showed no signs of caking or settling. The allopurinol suspension compounded from tablets was found to be pharmaceutically acceptable and easily pourable and redispersible. The energy of activation for the suspension was found to be 21.92 kcal/mol. The shelf-life (t90) of the suspension was found to be 8.3 years at room temperature.

Epstein-Barr virus nuclear antigen (EBNA)3C is an immortalizing oncoprotein with similar properties to adenovirus E1A and papillomavirus E7

Epstein-Barr virus (EBV) requires six genes to efficiently immortalize human B cells. We have shown that one of these, EBNA3C, can cooperate with activated (Ha-)ras in co-transfection assays to immortalize and transform rat embryo fibroblasts (REFs). EBNA3C also augmented transformation by (Ha-)ras and a mutant p53 to a similar extent as human papilloma virus E7. As with E7 this effect was not inhibited by cotransfection with the cyclin-dependent kinase inhibitor (CDKI), a p16INK4A, which can normally activate the retinoblastoma protein (pRb) and induce growth arrest. Also like E7/ras and E1A/ras transformed cells the EBNA3C/ras transformants are very susceptible to apoptotic cell death. In vitro EBNA3C binds to pRb in a manner which is dependent on the integrity of the pocket domain; this suggests that EBNA3C, even though it lacks the LXCXE pRb binding motif found in E7 and E1A, may interact with pRb in vivo. We conclude that EBNA3C functions as an oncoprotein which directs cell cycle progression through the G1 phase restriction point when conditions might signal arrest. For the first time this demonstrates that EBV encodes a protein, functionally but not necessarily mechanistically, similar to the pRb-neutralizing nuclear antigens encoded by the 'small' DNA tumor viruses.

Sperm competition games: external fertilization and "adaptive"' infertility

We develop a model of a continuous fertilization process in which eggs and sperm are shed simultaneously, and in which the eggs are fertilized at a rate proportional to sperm density surrounding the egg mass. The model derives the ESS size and number of sperm in an ejaculate of an externally-fertilizing animal such as a fish species, in which the probability or intensity of sperm competition varies. It also predicts the ESS level of infertility (eggs remaining unfertilized after all sperm have died). Sperm size is assumed to increase sperm competitive ability (e.g. by increasing speed) and is also assumed to affect sperm longevity (either positively or negatively). Ejaculate expenditure is traded off against expenditure on obtaining further spawnings, and size and number of sperm can vary independently. The model predicts that the ESS ejaculate expenditure (product of sperm size and number) should increase, and that the ESS infertility should decrease with sperm competition intensity measured across species. Other results depend on the way that sperm size affects longevity. The available biological evidence suggests that longevity decreases with sperm size, probably because the main increase is in tail length which increases sperm energy expenditure. In this case, sperm size should increase with sperm competition intensity from an optimum at zero competition which maximizes the total distance travelled by the entire ejaculate in its lifetime, to an optimum for maximum sperm competition which maximizes the product of speed and sperm number. However, if longevity increases with sperm size, then the non-competitive optimal sperm size is greater than that for maximum competition, so that sperm size decreases with sperm competition intensity. Sperm numbers typically increase with sperm competition intensity, and always so if sperm competition is high enough, though decreases are possible over a range of low sperm competition intensity if (i) sperm longevity decreases with sperm size, and (ii) infertility is high enough.

Ataxia associated with lymphosarcoma in a dog

A 4-year-old English Springer Spaniel with ataxia was examined because of progression of neurologic signs. Complete physical examination and results of CBC and serum biochemical analysis revealed no other abnormalities. The dog developed respiratory arrest and was euthanatized during recovery from general anesthesia, which had been performed to obtain a CSF sample. Results of CSF analysis were within reference limits. Necropsy revealed a single, well-circumscribed mass in the cerebellum, which was diagnosed as lymphosarcoma. The dog had no peripheral lymphadenopathy or organomegaly suggestive of the generalized form of the disease.

Liver lesions in rats associated with wrapping of the torso

Liver lesions were noted in control and dosed rats from a percutaneous toxicity study that involved wrapping of the torso to prevent oral ingestion following dermal application of test articles. Further investigation in a follow-up study revealed that the liver lesions were related to wrapping of the torso rather than to test-article administration because the liver lesions only appeared in wrapped animals, including sham-treated controls, but not in naive control animals. The liver lesions, which included centrilobular coagulative necrosis, inflammatory cell infiltration around biliary tracts, histiocytosis, fibrosis, and granulomatous inflammation, were compatible with infarction and associated inflammatory and reparative changes. There was no discernible pattern of involvement of specific hepatic lobes or regions of lobes. Many of the lesions were sufficiently severe to be considered life-threatening. This potentially significant complication should be considered when developing study protocols that involve wrapping of the torso of rats, and consideration should be given to inclusion of a naive control group that is not wrapped.

Dimensionless invariants from foraging theory's marginal value theorem

Copula duration (t) decreases, and proportional rate of sperm transfer (c) increases, with larger male body size in dung flies, so their dimensionless product (c. t) is approximately constant (approximately 2.2). The most recent copulating male fertilizes about 89% of the eggs laid (= 1 - e(-c.t) = 1 - e(-2.2)), independent of his body size. The conditions under which natural selection favors this phenotypic invariance are studied with fitness optimization models. The dimensionless rules for optimal patch residence times are then generalized to cover phenotypic variation in other foraging cases.

Punishment in animal societies

Although positive reciprocity (reciprocal altruism) has been a focus of interest in evolutionary biology, negative reciprocity (retaliatory infliction of fitness reduction) has been largely ignored. In social animals, retaliatory aggression is common, individuals often punish other group members that infringe their interests, and punishment can cause subordinates to desist from behaviour likely to reduce the fitness of dominant animals. Punishing strategies are used to establish and maintain dominance relationships, to discourage parasites and cheats, to discipline offspring or prospective sexual partners and to maintain cooperative behaviour.

Legal responsibilities of the pathologist

Pharmaceutical companies exist today in a hostile legal and regulatory environment. The threat of product liability in the pharmaceutical industry has risen to the point where it stifles research and development, especially for contraceptive and psychotropic drugs. Regulatory sanctions against the industry are more likely now than in the past since the Food and Drug Administration (FDA) has placed significant emphasis on regulatory inspection and enforcement. Industrial pathologists play a critical role in defending their company in product liability litigation and from regulatory sanctions. In-house and contract pathologists should be prepared to give expert testimony in court and ensure that an effective document retention policy is implemented. Pathologists should know the limits of the FDA's inspection authority and be aware of the "pitfalls" of the FDA's new Fraud Policy. In addition to keeping abreast of science, industrial pathologists today can best serve the pharmaceutical industry if they maintain an awareness of legal issues that pose a threat to the future success of the industry.

Histopathologic features and post-surgical sequelae of 57 cutaneous neoplasms in ferrets (Mustela putorius furo L.)

The study of the signalment, histomorphologic features, and post-surgical clinical progress of 57 cutaneous neoplasms in 55 domestic ferrets (Mustela putorius furo L.) was based on diagnostic pathologic accessions (1987-1992) from 142 ferrets. Mean age of the group was 4.3 years; 31/54 (57%) were female and 23/54 (43%) were male. Thirty-three (58%) of the cutaneous neoplasms were basal cell tumors. The mean age of ferrets with basal cell tumor was 5.2 years, and 23/33 (70%) were female. Histologically, the basal cell tumors were composed of well-differentiated basaloid epithelial cells with various degrees of squamous and sebaceous differentiation, similar to those seen in basal cell neoplasms of dogs. Nine of the 57 (16%) cutaneous neoplasms were mastocytomas. The mean age of ferrets with mastocytoma was 4.1 years; four were male, four were female, and the sex of one was unrecorded. Histologically, the mastocytomas were composed of well-differentiated mast cells with few eosinophils, similar to cutaneous mastocytomas of domestic cats. The mast cells had a small number of metachromatic cytoplasmic granules, and in six of eight neoplasms the granules had an affinity for conjugated avidin-peroxidase. Six of the cutaneous neoplasms (11%) were fibromas. The mean age of ferrets with fibroma was 2.7 years; 5 (83%) were male. Two cutaneous hemangiomas (4%) were in females, which were 4 and 5 years of age. There was one each hemangiosarcoma, cutaneous polyp, anal gland adenocarcinoma, lymphosarcoma of the prepuce and inguinal lymph node, and adenocarcinoma of the prepuce.

Sperm competition games: sperm size and sperm number under adult control

Evolutionary games of sperm competition in which two males mate with the same female have previously considered sperm size to be fixed at some (small) constant level. Although male gametes in multicellular organisms are typically small compared with ova, they vary greatly both between and within groups, and sperm size sometimes correlates with the probability of sperm competition. This paper examines 'raffle principle' sperm competition games in which both size and number of gametes can be varied strategically under control of the diploid parent. If ejaculate investment trades off against the number of matings that a male can achieve, the evolutionary stable strategy (ESS) ejaculate expenditure (as a fraction of reproductive effort per mating) approximates to p/4 when the probability, p, of sperm competition is low. Sperm size may either: (i) increase a sperm's competitive weight (a measure of its advantage in the fertilization raffle), or (ii) influence its mortality rate in the female tract. On the simplest model, size is optimized after the marginal value theorem, and may be large or small depending on how size influences competitive weight or survivorship. Further, sperm size is independent of the risk of sperm competition, and only sperm numbers increase with this risk. However, some recent studies show sperm size to increase with sperm competition. The present analysis offers the following possibilities: (i) there are unidentified constraints on sperm number, so that ejaculate mass can increase only by increase in sperm size; (ii) competitive benefits of size become more important as sperm numbers increase; (iii) size mainly increases survivorship, and sperm competition risk increases with the mean duration between mating and fertilization; and (iv) size increases competitive ability at the expense of survivorship, and sperm competition risk decreases with time between mating and fertilization. These conclusions relate to advantages conferred by size on sperm before fertilization; they do not affect the prediction of previous models that no component of sperm size should evolve for provisioning the zygote.

Sperm competition games: sperm size and number under gametic control

This paper examines sperm competition games in which both size and number of gametes in an ejaculate can be varied strategically, but under the control of the haploid sperm. It is a companion to the previous paper (Parker (Proc. R. Soc. Lond. B 253, 245 (1993))) for the case where the strategic control is by the diploid parent. Under haploid control, the optimal balance between size and number of sperm in an ejaculate becomes quite different from that predicted for diploid control; there is a conflict between parental and gametic interests over sperm size and number. This occurs because both intra-ejaculate and inter-ejaculate sperm competition are present with haploid control, whereas intra-ejaculate competition is absent under diploid control. The magnitude of this conflict is affected by the risk of inter-ejaculate sperm competition, and by the fact that gametic interests depend on the nature of available mutations. If ejaculate expenditure trades off against numbers of matings achieved, with haploid control there is escalation towards maximal expenditure on the ejaculate. If the ejaculate expenditure is fixed by the diploid parent, but there is a size-number trade-off under haploid control, solutions depend on the mode of action of the mutation affecting sperm size or number. If mutant-bearing sperm deviate entirely at the expense of non-mutant sperm, any increase in size or number will spread. If mutant sperm deviate entirely at their own expense, the evolutionarily stable strategy (ESS) is the same as for diploid control; there is no conflict.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of procainamide hydrochloride syrups compounded from capsules

The stability of procainamide hydrochloride in two oral syrups, one prepared with sucrose and the other with maltitol, was studied. A syrup containing powder from 500-mg procainamide hydrochloride capsules, simple sucrose syrup, and other additives was prepared; the theoretical initial concentration of procainamide hydrochloride was 50 mg/mL. Three samples each were stored at 40, 50, 60, and 70 degrees C. Drug concentration was measured with high-performance liquid chromatography at times ranging from 2 to 107 days. In a second study, a syrup containing powder from 500-mg procainamide hydrochloride capsules, a maltitol-based syrup vehicle, and other additives was prepared; the theoretical initial drug concentration was 50 mg/mL. Three samples each were stored at 40, 50, 60, and 70 degrees C. Drug concentration was measured at times ranging from 7 to 187 days. For the sucrose-based syrup, there was apparent first-order degradation of procainamide hydrochloride at all temperatures. An Arrhenius plot was used to calculate a shelf life of the syrup of 456 days at 25 degrees C. Most samples turned brown over time, and pH values were constant. For the maltitol-based syrup, drug degradation appeared to be biphasic; an initial period during which concentrations remained at nearly 100% was followed by apparent first-order degradation. Arrhenius plotting gave a shelf life of 97 days at 25 degrees C. Most samples turned brown over time, and pHs remained constant. Arrhenius plots indicated that in a maltitol-based oral syrup, procainamide hydrochloride was more stable than in a sucrose-based syrup when the storage temperature was above 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of hydralazine hydrochloride syrup compounded from tablets

The stability of hydralazine hydrochloride in an oral syrup and with various adjuvants that might be used in a liquid formulation was studied. A syrup containing triturated hydralazine hydrochloride 50-mg tablets, a maltitol-based syrup vehicle, and other additives was prepared; the theoretical initial concentration of hydralazine hydrochloride was 1.25 mg/mL. Three samples were each stored at 5, 40, 50, 60, and 70 degrees C. Drug concentration was measured with high-performance liquid chromatography at times ranging from 2 to 23 days. In a second study, five 50-mL solutions were prepared: (1) hydralazine 1% with no pH adjustment, (2) hydralazine 1% with pH adjusted to 6.33, (3) hydralazine 1% and edetate disodium 1% with no pH adjustment, (4) hydralazine 1% and edetate sodium 1% with no pH adjustment, and (5) hydralazine 1% and sodium bisulfite 1% with no pH adjustment. Drug concentration was determined after storage for one week at 50 degrees C. There was apparent first-order degradation of hydralazine hydrochloride at all temperatures. An Arrhenius plot was used to calculate a shelf life of the syrup of 5.13 days at 25 degrees C. There were no changes in pH or physical appearance. In the second study, hydralazine hydrochloride solution turned yellow immediately after edetate sodium [corrected] was added; at one week the loss of drug was 29%. Addition of sodium bisulfite caused a more intense yellow coloration, and loss of drug at one week was 80%. Changes in pH were minimal. An Arrhenius plot showed that hydralazine hydrochloride was relatively unstable in an oral syrup at room temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Mucinous biliary cystadenoma: a case report and review of the literature

Mucinous biliary cystadenomas are rare neoplasms with protean manifestations. In most cases the mucinous material is retained within the cyst itself. We describe an asymptomatic case of a mucin secreting biliary cystadenoma in which the mucin presented as an amorphous intraluminal filling defect in the common hepatic duct on endoscopic retrograde cholangiopancreatography (ERCP). The neoplasm itself was confined to the posterior segment of the right hepatic lobe and was treated by formal right hepatic lobectomy. This case prompted a review of mucinous biliary cystadenomas.

Formal hepatic resection of colorectal liver metastases. Ploidy and prognosis

Fifty consecutive patients who underwent 52 formal hepatic resections (excluding isolated wedge resections) for metastatic colorectal cancer were analyzed to determine whether DNA content was of prognostic significance. The Dukes' stages of the colorectal primaries were: A (10%), B (20%), C (40%), D (28%), and unknown in 2%. Four patients whose liver metastases were discovered at the time of resection of the primary bowel cancer underwent concomitant liver resection, and the remaining patients underwent delayed resections. The hepatic resections performed were right lobectomy (50%), extended right lobectomy (19%), left lobectomy (13%), left lateral segmentectomy (6%), left lobectomy and right wedge (6%), extended left lobectomy (4%), and right lobectomy and left wedge (2%). The overall morbidity rate was 29%. The in-hospital mortality rate was 9%. As of November 1991, 36 patients have recurred. The 5-year actuarial survival was 28%. Flow cytometry could be performed on 37 archival specimens, 15 of which were found to be diploid whereas 22 were aneuploid. All metastases from Dukes A colorectal primaries demonstrated a diploid DNA content. In addition, there was no difference in actuarial survival between diploid and aneuploid tumors. These data suggest that in selected patients, formal hepatic resection of colorectal liver metastases can be performed with an acceptable morbidity rate, mortality rate, and survival, but ploidy of the resected tumor is not of prognostic significance.

Evaluation of sodium hyaluronate therapy in induced septic arthritis in the horse

This study was conducted to determine the efficacy of sodium hyaluronate (SH) with antibiotic therapy and joint lavage for reducing acute inflammatory and degenerative changes induced by septic arthritis. Septic arthritis was induced in six adult horses by inoculating the tarsocrural joints with 1 x 10(4) colony-forming units of Staphylococcus aureus. When clinical signs appeared, trimethoprim-sulphamethoxazole (30 mg/kg bodyweight [bwt] daily) and phenylbutazone (4.4 mg/kg bwt sid) were administered and continued until termination of the study (Treatment Day 18). Twenty-four hours post inoculation, all joints were lavaged with sterile lactated Ringer's solution. Following lavage, one joint of each horse was injected with 10 mg of SH, and the contralateral joint served as the control. Sodium hyaluronate treated joints showed significant reductions in lameness, tarsal circumference and synovial fluid protein and WBC concentrations. The synovial membrane of the SH-treated joints contained less cellular infiltrate, less granulation tissue formation and retained a more normal villous structure compared with controls. The total glycosaminoglycan loss from the articular cartilage in the SH treated joints was consistently less than that from the control joints; however, this difference was not statistically significant. Sodium hyaluronate with joint lavage appears to be more beneficial than lavage alone for treatment of septic arthritis.

Intrathecal 5-fluorouracil in the rhesus monkey

Because meningeal spread of both leukemia and solid tumors remains a difficult therapeutic problem, there is a compelling need to develop new agents for intrathecal administration. 5-Fluorouracil (5FU), an active anticancer agent, penetrates into the central nervous system to some degree following intravenous dosing. Significant systemic toxicity, however, is associated with this route of administration. Therefore, the pharmacokinetic behavior of 5FU following its intrathecal administration was studied in a rhesus monkey model. After a 10-mg intraventricular dose, the disappearance of the drug from ventricular cerebrospinal fluid was monoexponential, the half-life being 51 min; the area under the concentration-time curve (AUC) being greater than 18 mM h-1; and the peak ventricular 5FU concentrations ranging between 10 and 15 mM. After a 1-mg intralumbar dose, the AUC was 1235 microM h-1. No toxicity was observed following intraventricular administration of 5FU. After intralumbar administration of either a 10-mg or a 1-mg dose, however, local toxicity was observed in the lumbar spinal cord. These findings suggest that intrathecal administration of 5FU is not presently a feasible means of achieving cytotoxic cerebrospinal fluid concentrations.

A model of constant random sperm displacement during mating: evidence from Scatophaga

This paper extends the sperm displacement model of Parker et al. (Behav. Ecol. Sociobiol. 27, 55 (1990)), in which sperm displacement is viewed as a process in which one unit of sperm introduced displaces one unit of sperm from the female's sperm stores. Here this process is envisaged in terms of the change in density of sperm in the sperm stores. In matings with virgin females, only sperm store fluid is displaced at the start of sperm transfer, but if there is swift random mixing of seminal and sperm store fluid, the fluid displaced will contain sperm at the same average density as that in the sperm stores (random displacement). In mating of the same female by two or more males, the sperm density of the last male to mate is assumed to be independent of the presence of previous sperm; P2 (the proportion of eggs fertilized by the last male) thus equals the density of the last male's sperm divided by the current total density of sperm in the sperm stores. Once the sperm stores have reached the asymptotic density (equivalent to the input density, i.e. the density of sperm in the seminal fluid), the present model becomes equivalent to that of Parker et al. (1990). Predictions for this model are tested using all available data from the dung fly, Scatophaga stercoraria. They are based on the assumption that sperm are transferred at a constant rate with copulation time. The data concur with this model, and we conclude that it is better than various other simple alternatives for explaining P2 in Scatophaga.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of methods used in the Florida Department of Agricultural and Consumer Services' Chemical Residue Laboratory

Very few methods for detecting residues of pesticides in food or agricultural samples have undergone rigorous colloborative study and possess official AOAC status. The Chemical Residue Laboratory has formalized a method validation scheme to use when incorporating or developing new, unofficial methods. These methods are validated by assessing certain performance parameters: scope, specificity, linear range, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). For accuracy and precision assessment, 12 replicate fortifications must yield recoveries within the range of 70-120% with a coefficient of variation (CV) that compares favorably to the Horwitz CV. LOD and LOQ are equivalent to 3 and 10 times, respectively, the background signal contributed by a sample matrix blank. This criterion that we use for LOD/LOQ is not universal. In fact, because of differing definitions, we have encountered difficulties in enforcing a tolerance by using a registrant's method. This paper also presents an example of our method validation scheme, using a recent method development project for detecting sulfamethazine in raw milk. The sulfamethazine project also revealed unanticipated personnel problems, underscoring the importance of the human factor in quality assurance.

Stability of acetazolamide in suspension compounded from tablets

The stability of acetazolamide in an extemporaneous suspension compounded from tablets was studied. Acetazolamide 25-mg/mL suspension was prepared by levigating the comminuted 250-mg tablets with 70% sorbitol solution. The mixture was incorporated into a suspension vehicle containing magnesium aluminum silicate and carboxymethylcellulose sodium. Appropriate sweeteners, flavoring agents, preservatives, humectants, and pH adjusters were then added. The suspension was stored in amber glass bottles at 5, 22, 30, 40, and 50 degrees C. Samples were analyzed for the concentration of acetazolamide by stability-indicating high-performance liquid chromatography on days 3, 7, 11, 18, 24, 32, 42, 54, and 79. For batches stored at 5, 22, and 30 degrees C, the initial acetazolamide concentration was maintained during the entire 79 days of the study. However, the concentrations in the batches stored at 40 and 50 degrees C were below 90% of the initial value after 79 and 32 days, respectively. The Arrhenius plot was used to predict a shelf life of the suspension at room temperature of 371 days. Acetazolamide oral suspension 25 mg/mL was stable for at least 79 days at 5, 22, and 30 degrees C. The formulation should be maintained at pH 4-5 and stored in amber glass bottles.