Surgical and nonsurgical management of primary and metastatic liver tumors

The medical records of 267 patients who had liver tumors, primary and metastatic, from 1988 to 1995 were retrospectively reviewed. Two hundred thirteen patients (80%) had metastatic disease, and 54 patients (20%) had primary liver disease. Their clinical manifestations and laboratory values were evaluated as factors predictive of diagnosis and survival. There was a significant increase in the occurrence of upper abdominal pain, weight loss, extrahepatic symptoms due to the metastatic origin, and hepatomegaly. Metastases from colorectal primary lesions were synchronous in 34 patients and metachronous in 31 patients. Stomach, lung, and pancreatic primaries were more commonly synchronous. Breast metastases were more commonly metachronous. Elevated serum glutamic-oxaloecetic transaminase and alkaline phosphatase and decreased albumin were the most common liver test abnormalities at diagnosis. Carcinoembryonic antigen values were elevated in the majority of colon cancer patients. Eighty-one percent of patients with primary liver cancer had elevated levels of alpha-fetoprotein, 40 per cent were seropositive for hepatitis B, and 23 per cent were seropositive for hepatitis C. Seventy-nine patients (30%) underwent surgery for their cancer, 37 (47%) had resections, 38 (48%) were unresectable, and 4 (5%) underwent liver transplantation. The patients who underwent surgery had a 32 per cent 5-year survival rate compared to a 0 per cent 5-year survival in the patients who did not have surgery (p = 0.0001). The patients who had resections had a better survival rate than those deemed unresectable at surgery (62% versus 0% at 5-years with p = 0.0008). The perioperative morbidity rate was 16 per cent, with lobectomies having the best rate and trisegmentectomies having the worst. Perioperative mortality rate was zero for all liver resections. Hepatic resection and, in selected patients, liver transplantation are the only two available therapeutic modalities that produce long-term survival with a possible cure in patients with primary and metastatic liver tumor.     

A new pitheciin primate from the middle Miocene of Argentina

We report here a new fossil primate from the middle Miocene of Argentina. The material consists of isolated teeth, mandibular fragments, and a talus. The fossils were collected in the Collón Cura formation at Ca?adón del Tordillo in Neuquén Province. An age of 15.71 +/- 0.07 Ma has been reported for the Pilcaniyeu Ignimbrite, which lies just below the paleosols in which the fossils were found. This material is thus the youngest occurrence of fossil primates in Argentina (hitherto documented in the Santacrucian and older land mammal ages) but still is older than the middle Miocene platyrrhine primates from La Venta, Colombia, in particular the pitheciins Nuciruptor and Cebupithecia. The material is recognized as a new genus and species of Pitheciinae, Propithecia neuquenensis. The mesiodistally compressed, high-crowned incisors are specialized and similar to species in the tribe Pithecini and to the nonpitheciin Soriacebus (early Miocene, Patagonia). We rule out a phylogenetic relationship to the latter because of differences in molar morphology. Propithecia does, however, fit well into the pattern of pitheciin evolution, being more derived than the middle Miocene pitheciin Nuciruptor but not as much as another middle Miocene taxon, Cebupithecia. As such, this makes Propithecia the oldest taxon that can be confidently placed within this modern New World monkey subfamily. By analogy with the molar structures and diets of extant platyrrhines, Propithecia has a molar structure consistent with a variety of low-fiber diets ranging from fruit and gum to seeds. Its incisors suggest seed-eating in much the same way as extant pitheciins, like Pithecia. The talus resembles that of Callicebus, suggesting arboreal quadrupedal locomotion.     

Histopathological changes in Yucatan minipig skin following challenge with sulphur mustard. A sequential study of the first 24 hours following challenge

The importance of calcium in neuronal function has been amply demonstrated in recent years. The discovery of a class of proteins within neurons which bind calcium, therefore, has proven to be a catalyst for the generation of theories and hypotheses regarding mechanisms of neurotoxicity in the CNS. In addition, the distribution of certain calcium-binding proteins changes during neural development, suggesting that they may play a role in organization or pattern generation. We have examined the ontogeny of three related calcium-binding proteins, calbindin-D28, parvalbumin and calretinin, with respect to the ventral and dorsal compartments or tiers of the dopaminergic population in the ventral midbrain. Single and dual-label immunocytochemistry was employed to map the distributions of calcium-binding proteins and tyrosine hydroxylase from E18 through adulthood. The results show that each of the three proteins exhibits a unique developmental sequence and compartment preference, with calbindin D28 clearly related to the later-developing dorsal tier, and parvalbumin and calretinin to the ventral tier of the dopaminergic ventral mesencephalon.     

Outpatient laparoscopic cholecystectomy: safe and cost effective?

OBJECTIVE: Reports on the aetiology and risk of occupational rhinitis in different occupations are scarce. METHOD: The purpose of this study was to find the occupations with an increased risk of occupational rhinitis. Age and gender differences in occupational rhinitis and occupational asthma were also compared, and the most common causes of occupational rhinitis were analysed. DESIGN: This study covered the cases of occupational rhinitis and asthma reported to the Finnish Register of Occupational Diseases during the years 1986-1991. The cases on the Register were linked to the longitudinal census data file from the Finnish censuses. RESULTS: During 1986-1991, 1244 new cases of occupational rhinitis (474 women and 497 men) and 1867 new cases of occupational asthma (916 women and 951 men) were reported to the Register. Animal dander, flours, wood dusts, textiles, phthalic acid anhydrides and storage mites were important causes of occupational rhinitis. The highest relative risk of occupational rhinitis was among furriers, the age-standardized rate ratio (SRR) was 30.0. Bakers and livestock breeders had also a markedly elevated relative risk (SRR = 22.0). Men had the highest incidence of occupational rhinitis at the age of 25-29 years and among women the incidence gradually increased and reached the peak in the group 40-44 years of age. CONCLUSION: Furriers, bakers, and livestock breeders had the most elevated relative risk of occupational rhinitis. Occupational rhinitis cases reported at a younger age than asthma, suggesting that rhinitis often precedes asthma.     

Pharmacodynamics of (-)-beta-2',3'-dideoxy-3'-thiacytidine in chronically virus-infected woodchucks compared to its pharmacodynamics in humans

The pharmacodynamics of (-)-beta-2',3'-dideoxy-3'-thiacytidine (3TC) was studied in chronically woodchuck hepatitis virus-infected woodchucks and compared to that in previous studies in hepatitis B virus (HBV)-infected humans. Net depletion rates of serum virus DNA in woodchucks receiving 3TC were modeled as a sum of an exponentially declining virus input and a first-order elimination. Preceding shoulders and pseudo-first-order virus half-lives in serum ranged from 1 to 7 days and were dose dependent. Higher plasma 3TC concentrations were needed in woodchucks for virus depletion similar to that attained in humans. Human HBV depletion curves from a previous clinical study with 3TC (>/=100 mg per day) were described by a biexponential relationship. The average half-life value in humans, normalized to fraction of area under the serum virus load-time curve, was similar to the average half-life value observed in woodchucks given the highest 3TC dose (2.4 and 2.0 days, respectively). On cessation of therapy, virus load rebounds in woodchucks were dose dependent and resembled posttherapy virus "flares" reported to occur in humans. The estimates of drug exposures that could lead to optimal antiviral effects presented indicate that 3TC should not be underdosed and compliance should be monitored. The study of chronically infected woodchucks may prove useful for optimizing drug regimens for hepadnavirus infections.     

Estimating multiple temporal mechanisms in human vision

When studying human ability to perceive temporal changes in luminance it is customary to estimate either temporal impulse response shapes or temporal modulation transfer functions, the representation of the impulse response in the frequency domain. The advantages and limitations of previous methods are summarized. We then describe an approach based on use of an impulse response basis set that resolves some of those limitations. We next present psychophysical results for spatiotemporal signal detection in spatiotemporal noise, together with an economical model of performance. The model is based on accepted notions of psychophysical detection mechanisms and the filter basis set described in the first part of the paper. The best-fitting model requires only eight parameters, as opposed to the 198 parameters required to separately fit each psychometric function, and captures both qualitative and quantitative properties of the psychophysical data. Finally, the best-fitting model indicates that only two temporal filters are necessary to describe the performance of each of three subjects under the specific stimulus conditions employed here.     

Solute washout experiments for characterizing mass transport in hollow fiber immunoisolation membranes

The transport characteristics of immunoisolation membranes can have a critical effect on the design of hybrid artificial organs and cell therapies. However, it has been difficult to quantitatively evaluate the desired transport properties of different hollow fiber membranes due to bulk mass transfer limitations in the fiber lumen and annular space. An attractive alternative to existing methodologies is to use the rate of solute removal or "washout" from the annular space during constant flow perfusion through the fiber lumen. Experimental washout curves were obtained for glucose and a 10 kD dextran in two different hollow fiber devices. Data were analyzed using a theoretical model which accounts for convective and diffusive transport in the lumen, membrane, and annular space. The model was in good agreement with the experimental results and provided an accurate measure of the effective membrane diffusion coefficient for both small and large solutes. This approach should prove useful in theoretical analyses of solute transport and performance of hollow fiber artificial organs.     

Brain opioid receptor measurements by positron emission tomography in normal cycling women: relationship to luteinizing hormone pulsatility and gonadal steroid hormones

The regulation of central mu-opioid receptors in women during the menstrual cycle was explored with positron emission tomography and the selective radiotracer [11C]carfentanil. Ten healthy women were studied twice, during their follicular and luteal phases. Plasma concentrations of estradiol, progesterone, testosterone, and beta-endorphin were determined immediately before scanning. LH pulsatility was measured over the 9 h preceding each of the two positron emission tomography scans. No significant differences in the binding potential of mu-opioid receptors (binding capacity/Kd) were observed between phases of the menstrual cycle. However, significant negative correlations were observed between circulating levels of estradiol during the follicular phase and mu-receptor binding measures in the amygdala and hypothalamus, two regions thought to be involved in the regulation of GnRH pulsatility. LH pulse amplitude was positively correlated with mu binding in the amygdala, whereas LH pulse number was negatively correlated with binding in this same region. No significant associations were noted between LH pulse measures and the hypothalamus for this sample. These results suggest that amygdalar mu-opioid receptors exert a modulatory effect on GnRH pulsatility, and that circulating levels of estradiol also regulate central mu-opioid function.