Estimation of breeding population size using DNA-based pedigree reconstruction in brown bears

Robust estimates of demographic parameters are critical for effective wildlife conservation and management but are difficult to obtain for elusive species. We estimated the breeding and adult population sizes, as well as the minimum population size, in a high-density brown bear population on the Shiretoko Peninsula, in Hokkaido, Japan, using DNA-based pedigree reconstruction. A total of 1288 individuals, collected in and around the Shiretoko Peninsula between 1998 and 2020, were genotyped at 21 microsatellite loci. Among them, 499 individuals were identified by intensive genetic sampling conducted in two consecutive years (2019 and 2020) mainly by noninvasive methods (e.g., hair and fecal DNA). Among them, both parents were assigned for 330 bears, and either maternity or paternity was assigned to 47 and 76 individuals, respectively. The subsequent pedigree reconstruction indicated a range of breeding and adult (≥4 years old) population sizes: 128-173 for female breeders and 66-91 male breeders, and 155-200 for female adults and 84-109 male adults. The minimum population size was estimated to be 449 (252 females and 197 males) in 2019. Long-term continuous genetic sampling prior to a short-term intensive survey would enable parentage to be identified in a population with a high probability, thus enabling reliable estimates of breeding population size for elusive species.

Diel and monthly activity pattern of brown bears and sika deer in the Shiretoko Peninsula, Hokkaido, Japan

Mammals exhibit several types of diel activity pattern, including nocturnal, diurnal, crepuscular, and cathemeral. These patterns vary inter- and intra-specifically and are affected by environmental factors, individual status, and interactions with other individuals or species. Determining the factors that shape diel activity patterns is challenging but essential for understanding the behavioral ecology of animal species, and for wildlife conservation and management. Using camera-trap surveys, we investigated the species distributions and activity patterns of terrestrial mammals on the Shiretoko Peninsula, Hokkaido, Japan, with particular focus on brown bears and sika deer. From June to October 2019, a total of 7,530 observations were recorded by 65 camera-traps for eight species, including two alien species. The diel activity pattern of brown bears was diurnal/crepuscular, similar to that of bears in North America, but different from European populations. Bear observations were more frequent during the autumnal hyperphagia period, and adult females and sub-adults were more diurnal than adult males. In addition, bears inside the protected area were more diurnal than those outside it. These findings suggest that appetite motivation, competitive interactions between conspecifics, and human activities potentially affect bear activity patterns. Similar to other sika deer populations and other deer species, the diel activity patterns of sika deer were crepuscular. Deer showed less variation in activity patterns among months and sex-age classes, while adult males were observed more frequently during the autumn copulation period, suggesting that reproductive motivation affects their activity patterns.

Dining from the coast to the summit: Salmon and pine nuts determine the summer body condition of female brown bears on the Shiretoko Peninsula

Body condition in mammals fluctuates depending on energy intake and expenditure. For brown bears (Ursus arctos), high-protein foods facilitate efficient mass gain, while lipids and carbohydrates play important roles in adjusting dietary protein content to optimal levels to maximize energy intake. On the Shiretoko Peninsula, Hokkaido, Japan, brown bears have seasonal access to high-lipid pine nuts and high-protein salmon. To assess seasonal and annual fluctuation in the body condition of adult female brown bears in relation to diet and reproductive status, we conducted a longitudinal study in a special wildlife protection area on the Shiretoko Peninsula during 2012-2018. First, analyses of 2,079 bear scats revealed that pine nuts accounted for 39.8% of energy intake in August and salmon accounted for 46.1% in September and that their consumption by bears varied annually. Second, we calculated the ratio of torso height to torso length as an index of body condition from 1,226 photographs of 12 adult females. Results indicated that body condition continued to decline until late August and started to increase in September when salmon consumption increased. In addition, body condition began to recover earlier in years when consumption of both pine nuts and salmon was high. Furthermore, females with offspring had poorer body condition than solitary females, in particular in late August in years with low salmon consumption. Our findings suggest that coastal and subalpine foods, which are unique to the Shiretoko Peninsula, determine the summer body condition of female brown bears, as well as their survival and reproductive success.

Development of a noninvasive photograph-based method for the evaluation of body condition in free-ranging brown bears

Body condition is an important determinant of health, and its evaluation has practical applications for the conservation and management of mammals. We developed a noninvasive method that uses photographs to assess the body condition of free-ranging brown bears (Ursus arctos) in the Shiretoko Peninsula, Hokkaido, Japan. First, we weighed and measured 476 bears captured during 1998–2017 and calculated their body condition index (BCI) based on residuals from the regression of body mass against body length. BCI showed seasonal changes and was lower in spring and summer than in autumn. The torso height:body length ratio was strongly correlated with BCI, which suggests that it can be used as an indicator of body condition. Second, we examined the precision of photograph-based measurements using an identifiable bear in the Rusha area, a special wildlife protection area on the peninsula. A total of 220 lateral photographs of this bear were taken September 24–26, 2017, and classified according to bear posture. The torso height:body/torso length ratio was calculated with four measurement methods and compared among bear postures in the photographs. The results showed torso height:horizontal torso length (TH:HTL) to be the indicator that could be applied to photographs of the most diverse postures, and its coefficient of variation for measurements was <5%. In addition, when analyzing photographs of this bear taken from June to October during 2016–2018, TH:HTL was significantly higher in autumn than in spring/summer, which indicates that this ratio reflects seasonal changes in body condition in wild bears. Third, we calculated BCI from actual measurements of seven females captured in the Rusha area and TH:HTL from photographs of the same individuals. We found a significant positive relationship between TH:HTL and BCI, which suggests that the body condition of brown bears can be estimated with high accuracy based on photographs. Our simple and accurate method is useful for monitoring bear body condition repeatedly over the years and contributes to further investigation of the relationships among body condition, food habits, and reproductive success.

Male reproductive input, breeding tenure, and turnover in high-density brown bear (Ursus arctos yesoensis) populations on the Shiretoko Peninsula, Hokkaido, Japan

Male reproductive behavior has not been thoroughly investigated in large, non-social mammals. We studied male reproductive input using field observations and microsatellite DNA data for the brown bear (Ursus arctos yesoensis Lydekker, 1897) population in a special wildlife protection area on the Shiretoko Peninsula in Hokkaido, Japan. We identified the father of 82 offspring born between 2006 and 2018 from 54 litters produced by 20 females and revealed that they were sired by a total of 19 males. Overall, paternity was distributed relatively evenly among different males, although litter production tended to be skewed to a few bears in some years. Male breeding tenure varied among individuals, but most tenures were within the range of 1 to 6 years. Human-caused mortality, mostly occurring near human residential areas, induced male turnover, indicating that the special wildlife protection area located in the inner part of the Shiretoko Peninsula is not free from human impact. The frequency of successful reproduction was highest in 10- to 14-year-old bears, which is consistent with the period when males reach physical maturity. These results contribute to an understanding of breeding systems in large solitary mammals and to appropriate conservation and management strategies for brown bear populations.

Frontiers in pediatric testicular torsion: An integrated review of prevailing trends and management outcomes

Testicular torsion remains the most frequent cause of testicular ischemia, especially in adolescents and young adults. Timely diagnosis and intervention are keys to saving the affected testicle. This review presents current trends in the diagnosis and treatment of torsion, potential pitfalls and consequent outcomes. Additionally, other salient issues surrounding testicular torsion are also discussed, including: pathogenesis of injury, legal ramifications, fertility outcomes, novel management techniques, and recent advances in diagnostic technology.

GPRC5A is a potential oncogene in pancreatic ductal adenocarcinoma cells that is upregulated by gemcitabine with help from HuR

GPRC5A is an orphan G-protein coupled receptor with an intriguing dual behavior, acting as an oncogene in some cancers and as a tumor suppressor in other cancers. In the pancreatic cancer context, very little is known about GPRC5A. By analyzing messenger RNA (mRNA) expression data from 675 human cancer cell lines and 10 609 samples from The Cancer Genome Atlas (TCGA) we found that GPRC5A's abundance in pancreatic cancer is highest (cell lines) or second highest (TCGA) among all tissues and cancer types. Further analyses of an independent set of 252 pancreatic normal and cancer samples showed GPRC5A mRNA to be more than twofold upregulated in primary tumor samples compared with normal pancreas (P-value<10⁻⁵), and even further upregulated in pancreatic cancer metastases to various organs (P-value=0.0021). Immunostaining of 208 cores (103 samples) of a tissue microarray showed generally low expression of GPRC5A protein in normal pancreatic ductal cells; on the other hand, in primary and metastatic samples, GPRC5A protein levels were dramatically increased in pancreatic ductal cells. In vitro studies of multiple pancreatic cancer cell lines showed that an increase in GPRC5A protein levels promoted pancreatic cancer cell growth and migration. Unexpectedly, when we treated pancreatic cancer cell lines with gemcitabine (2′,2′-difluorodeoxycytidine), we observed an increase in GPRC5A protein abundance. On the other hand, when we knocked down GPRC5A we sensitized pancreatic cancer cells to gemcitabine. Through further experimentation we showed that the monotonic increase in GPRC5A protein levels that we observe for the first 18 h following gemcitabine treatment results from interactions between GPRC5A's mRNA and the RNA-binding protein HuR, which is an established key mediator of gemcitabine's efficacy in cancer cells. As we discovered, the interaction between GPRC5A and HuR is mediated by at least one HuR-binding site in GPRC5A's mRNA. Our findings indicate that GPRC5A is part of a complex molecular axis that involves gemcitabine and HuR, and, possibly, other genes. Further work is warranted before it can be established unequivocally that GPRC5A is an oncogene in the pancreatic cancer context.

The mRNA-binding protein HuR promotes hypoxia-induced chemoresistance through posttranscriptional regulation of the proto-oncogene PIM1 in pancreatic cancer cells

Previously, it has been shown that pancreatic ductal adenocarcinoma (PDA) tumors exhibit high levels of hypoxia, characterized by low oxygen pressure (pO2) and decreased O2 intracellular perfusion. Chronic hypoxia is strongly associated with resistance to cytotoxic chemotherapy and chemoradiation in an understudied phenomenon known as hypoxia-induced chemoresistance. The hypoxia-inducible, pro-oncogenic, serine-threonine kinase PIM1 (Proviral Integration site for Moloney murine leukemia virus 1) has emerged as a key regulator of hypoxia-induced chemoresistance in PDA and other cancers. Although its role in therapeutic resistance has been described previously, the molecular mechanism behind PIM1 overexpression in PDA is unknown. Here, we demonstrate that cis-acting AU-rich elements (ARE) present within a 38-base pair region of the PIM1 mRNA 3'-untranslated region mediate a regulatory interaction with the mRNA stability factor HuR (Hu antigen R) in the context of tumor hypoxia. Predominantly expressed in the nucleus in PDA cells, HuR translocates to the cytoplasm in response to hypoxic stress and stabilizes the PIM1 mRNA transcript, resulting in PIM1 protein overexpression. A reverse-phase protein array revealed that HuR-mediated regulation of PIM1 protects cells from hypoxic stress through phosphorylation and inactivation of the apoptotic effector BAD and activation of MEK1/2. Importantly, pharmacological inhibition of HuR by MS-444 inhibits HuR homodimerization and its cytoplasmic translocation, abrogates hypoxia-induced PIM1 overexpression and markedly enhances PDA cell sensitivity to oxaliplatin and 5-fluorouracil under physiologic low oxygen conditions. Taken together, these results support the notion that HuR has prosurvival properties in PDA cells by enabling them with growth advantages in stressful tumor microenvironment niches. Accordingly, these studies provide evidence that therapeutic disruption of HuR's regulation of PIM1 may be a key strategy in breaking an elusive chemotherapeutic resistance mechanism acquired by PDA cells that reside in hypoxic PDA microenvironments.

Bioactive Molecules from Sea Hares

Sea hares, belonging to the order Opisthobranchia, subclass Gastropoda, are mollusks that have attracted many researchers who are interested in the chemical defense mechanisms of these soft and "shell-less" snails. Numbers of small molecules of dietary origin have been isolated from sea hares and some have ecologically relevant activities, such as fish deterrent activity or toxicity. Recently, however, greater attention has been paid to biomedically interesting sea hare isolates such as dolastatins, a series of antitumor peptide/macrolides isolated from Dolabella auricularia. Another series of bioactive peptide/macrolides, as represented by aplyronines, have been isolated from sea hares in Japanese waters. Although earlier studies indicated the potent antitumor activity of aplyronines, their clinical development has never been conducted because of the minute amount of compound available from the natural source. Recent synthetic studies, however, have made it possible to prepare these compounds and analogs for a structure-activity relationship study, and started to uncover their unique action mechanism towards their putative targets, microfilaments. Here, recent findings of small antitumor molecules isolated from Japanese sea hares are reviewed. Sea hares are also known to produce cytotoxic and antimicrobial proteins. In contrast to the small molecules of dietary origin, proteins are the genetic products of sea hares and they are likely to have some primary physiological functions in addition to ecological roles in the sea hare. Based on the biochemical properties and phylogenetic analysis of these proteins, we propose that they belong to one family of molecule, the "Aplysianin A family," although their molecular weights are apparently divided into two groups. Interestingly, the active principles in Aplysia species and Dolabella auricularia were shown to be L-amino acid oxidase (LAAO), a flavin enzyme that oxidizes an alpha-amino group of the substrate with molecular oxygen and liberates hydrogen peroxide, with a sequence similar to other known LAAOs, including snake venom. Possible antibacterial activity and cytotoxic activity mechanisms of these proteins are also discussed.

Cloning of the Microcystis aeruginosa M228 lectin (MAL) gene

We have cloned and characterized the gene encoding Microcystis aeruginosa (strain M228) lectin (MAL). The gene contains 1551 nucleotides and an open reading frame for a protein of 517 amino acids with a predicted molecular weight of 55,159 Da. The carboxy-terminal region of MAL has three tandemly repeated homologous domains composed of 61 amino acids. These regions show similarity to the corresponding regions of the alpha-amylase of Clostridium beijerinckii (23% identity). The mal gene lies adjacent to an ORF that display homology to cytochrome P-450 and polyketide synthase. Southern hybridization showed that the genomic DNA of the strain M228 contained, in addition to MAL gene (mal), at least two other mal like gene.

Development of a new inhibitor of glucosylceramide synthase

Analogs of the potent inhibitor of glucosylceramide (GlcCer) synthase, D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4), based on substitutions in the palmitoyl group were made by means of a stereo-selective synthetic method in order to elucidate the role of the hydrophobic portion in both the inhibitory action toward the enzyme and the biological effects. While P4 strongly inhibited GlcCer synthase with an IC(50) of 0.5 microM in vitro, it also inhibited cell growth by 50% at the concentration of 7 microM. The shorter N-acyl chain analogs including decanoyl, octanoyl, and hexanoyl groups showed similar IC(50) values for GlcCer synthase (around 2 microM) but the hexanoyl analog exhibited only a slight inhibitory effect on cell growth, showing the dissociation between GlcCer depletion and cell growth. Several compounds which exhibit similar hydrophobicity to the hexanoyl analog of P4 were subsequently designed. We found that D-threo-1-phenyl-2-benzyloxycarbonylamino-3-pyrrolidino-1-pr opanol (PBPP) was a most potent inhibitor, showing an IC50 of 0.3 microM. In cultured cells, PBPP was able to deplete glycosphingolipids without affecting cell growth or the ceramide level.

The D-galactose-binding lectin of the octocoral Sinularia lochmodes: characterization and possible relationship to the symbiotic dinoflagellates

A D-galactose binding lectin (SLL-2) was isolated from Sinularia lochmodes, an octocoral, by a combination of affinity chromatography on acid-treated agarose and FPLC on Superdex 200. SLL-2 agglutinated rabbit and horse erythrocytes while SLL-1, a minor component, reacted only with rabbit erythrocytes. SLL-2 is a glycoprotein with a molecular mass of 122 kDa and is composed of eight identical subunits (15 kDa). The sequence of the amino terminal region of SLL-2 did not show any apparent homology to the sequences of other animal and plant lectins. D-Galactose, N-acetyl-D-galactosamine, lactose, and melibiose were moderate inhibitors to the agglutination of rabbit erythrocytes. In contrast, horse erythrocytes were much more susceptible to agglutination by SLL-2, which was inhibited by sugars and glycoproteins such as D-galactose, N-acetyl-D-galactosamine, lactose, melibiose, and porcine stomach mucin. SLL-2 showed considerable tolerance to heating and kept its activity after heating at 80 degrees C for 60 min. In immuno-histochemical studies using an anti-SLL-2 antiserum and protein A gold conjugate, SLL-2 was found to be present in high amounts in the nematocysts. SLL-2 was also detected on the surface of symbiotic dinoflagellate, Symbiodinium sp. cells irrespective whether they were surrounded with or without host cells. These observations suggest the presence of lectin-mediated interaction between symbiotic dinoflagellates and S. lochmodes.

Isolation and characterization of a mannan-binding lectin from the freshwater cyanobacterium (blue-green algae) Microcystis viridis

Microcystis viridis NIES-102 strain, a unicellular freshwater bloom-forming cyanobacterium, showed transient hemagglutinating activity in laboratory culture during stationary phase under nonaeration conditions. However, the hemagglutinating activity which was inhibited with yeast mannan could not be observed during culture with aeration. A mannan-binding lectin named MVL was isolated with the assay of the hemagglutinating activity against rabbit erythrocytes from the cyanobacterium by successive hydrophobic and gel filtration chromatography. MVL was composed of a single polypeptide of 13 kDa. The gene (mvl) for MVL was cloned from a genomic DNA of NIES-102 strain as a template, and its sequence was determined. The deduced amino acid sequence showed that MVL consisted of 113 amino acid residues and was composed of two tandemly repeated homologous domains of 54 amino acid residues. MVL showed no sequence homology to any other lectins or proteins.

Late cyst convolution after gamma knife radiosurgery for cerebral arteriovenous malformations

Although many series of patients with cerebral arteriovenous malformations (AVMs) treated radiosurgically have been published, there has been little information on cysts appearing several years after irradiation. Herein, we discuss the incidence, mechanisms and predictability of late cyst formation based on our personal experiences, as well as reported patients. The incidence of this complication, though generally considered to be 0.5% or less, may be higher than assumed. Although a breakdown of the blood-brain barrier is likely to play a major role in the formation process, the hematoma cavity itself may have the potential to become a cyst. A radiation-induced lesion appearing several years after irradiation and persisting for several years thereafter may be a warning sign of late cyst formation. Long-term follow-up, particularly using neuroimaging techniques, is necessary even after the 'treatment goal' has been achieved.

Chemical modification of beta-glucocerebrosidase inhibitor N-octyl-beta-valienamine: synthesis and biological evaluation of N-alkanoyl and N-alkyl derivatives

Several N-alkanoyl 4a-d and N-alkyl derivatives 5a-g of the potent beta-glucocerebrosidase inhibitor N-octyl beta-valienamine (3) were synthesized in order to elucidate a role of hydrophobic portion in the inhibitory action. Although the former lacked inhibitory potency, the latter were strong beta-glucocerebrosidase inhibitors (cf. N-decyl-N-octyl-beta-valienamine 5d: Ki 6.6 x 10(-8) M). Furthermore, when being prescribed into mouse-derived B16 melanoma cells, N-butyl-N-octyl-beta-valienamine 5a and 5d were shown to change the amount of GlcCer and GM3, which suggests that they are possibly introduced into cells and influence glycolipids biosynthesis.

Synthesis and evaluation of morpholino- and pyrrolidinosphingolipids as inhibitors of glucosylceramide synthase

This paper describes the new synthesis and evaluation of some morpholino- and pyrrolidinosphingolipids and mimics as inhibitors of glucosylceramide synthase. It was found that the pyrrolidino derivatives are generally more active than the morpholino derivatives and the best one was shown to be a nanomolar inhibitor.

Inhibitory effects of catecholamines and maternal stress on aromatase activity in the fetal rat brain

OBJECTIVE

Aromatization in the the fetal brain is thought to be involved both in sex differentiation during early development and in adult sexual behavior. Although recently the relationship between aromatase and catecholamine has been discussed, the effect of stress on aromatase in the fetal brain has not been clarified. Therefore, in the present study, localization of aromatase and the inhibitory effects of catecholamines and maternal stress on aromatase activity in the fetal rat brain were examined.

METHODS

Localization of aromatase cytochrome P-450 using a specific polyclonal antiserum against human placenta aromatase was examined, and the inhibitory effects of dopamine and norepinephrine on aromatase activity in vitro were studied. Further, the influences of intrauterine stress on aromatase activity in the prenatal rat brain were evaluated in vivo.

RESULTS

Aromatase-immunoreactive neurons are located principally in the medial amygdaloid nucleus. Aromatase activity in the fetal rat brain was competitively inhibited by dopamine and norepinephrine, with Ki values of 120 microM and 100 microM, respectively. Aromatase activity in the fetal brain was significantly lower in stressed rats given 1.5% salt water (89.2 +/- 17.5 fmol/mg/hr; n = 4) (p < 0.05) than in the control group (123.1 +/- 10.0 fmol/mg/hr; n = 4).

CONCLUSION

Aromatase activity in the prenatal rat brain is influenced by catecholamine metabolism during intrauterine stress.

A synthetic ceramide analog (L-PDMP) up-regulates neuronal function

To address the role of brain gangliosides in synaptic activity, the ceramide analogs, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) and its enantiomer, L-PDMP, were used to inhibit and stimulate ganglioside biosynthesis in cultured cortical neurons. Prolonged treatment with both PDMP isomers exhibited opposite effects on functional synapse formation measured by spontaneous synchronized oscillatory activity of intracellular Ca2+ between the neurons: suppression by D-PDMP and facilitation by L-PDMP. Up-regulation of synaptic activity by L-PDMP could be correlated with the slow but robust activation of p42 mitogen-activated protein kinase. Treatment with L-PDMP after transient forebrain ischemia in rats ameliorated the deficit of a well-learned spatial memory by an 8-arm maze task, suggesting a new potential therapeutic approach for neurodegenerative disorders.

Conservative management of acoustic neurinomas: prospective study of long-term changes in tumor volume and auditory function

Recently reported retrospective analysis on the natural courses of acoustic neurinomas have disclosed that 26-86% of tumors show very slow, or no, growth for many years. To our knowledge, however, there have been no prospective analyses of the natural course of these tumors. We prospectively analyzed tumor growth as well as auditory function changes in 12 patients (13 tumors) managed conservatively. All 12 patients were advised to undergo both pure tone audiometry and magnetic resonance imaging at 3-4 month intervals for the first follow-up year and at 1-2 year intervals thereafter. Then, in the event of either significant tumor growth (> 20% volume increase) or hearing deterioration (> 10 dB), a decision would be made as to whether the patient should undergo either surgery or radiosurgery. A significant increase in tumor volume was confirmed in seven of the 13 tumors during the mean observation period of 564 days (88-1269 days). In another patient, though neither tumor growth nor worsening of auditory acuity was significant, the patient complained of subjective change in the symptoms. Therefore, we decided to treat eight (62%) of the 13 tumors. In contrast, neither tumor growth nor worsening of auditory acuity has as yet occurred in the remaining five tumors (38%) which have been observed for a mean period of 627 days (342-1377 days). Careful follow-up of these five patients is ongoing. Although further long-term follow-up is clearly necessary, conservative treatment appears to be a reasonable alternative to immediate treatment for selected patients with acoustic neurinomas.

Radiation-related adverse effects observed on neuro-imaging several years after radiosurgery for cerebral arteriovenous malformations

BACKGROUND

To our knowledge, there are no reported arteriovenous malformation (AVM) series in which detailed long-term follow-up results after radiosurgery were described based on the whole patient group.

METHOD

We performed a detailed long-term follow-up study of 53 patients with cerebral AVMs treated with gamma knife (GK) radiosurgery, with emphasis on radiation-related adverse effects detected on neuro-imaging after a long post-irradiation latency period (3-10 years). The post-GK follow-up period was 40-232 months excluding two mortalities, the mean being 112 and the median being 111 months.

RESULTS

Three patients (5.6%) have, as yet, refused all neuro-imaging follow-up studies. Complete nidus obliteration was confirmed angiographically in 32 patients (60.4%) between 1 and 5 post-GK years. In the other 18 patients (34%), despite significant nidus shrinkage being angiographically demonstrated, complete obliteration was not achieved during a 2-7 year follow-up period. There were two mortalities, one AVM-related (massive re-bleeding during the latency period) and the other angiography-related. There were five radiation-related morbidities (9.4%), three of which-hemi-Parkinson syndrome, hemiparesis, and visual field disturbances attributable to delayed cyst formation-manifested at 5.5, 7 and 7 post-GK years, respectively. We also experienced five patients (9.4%) in whom, despite remaining asymptomatic to date, radiation-related adverse effects were seen on neuro-imaging: middle cerebral artery stenosis at 3 post-GK years in one patient; dural arteriovenous fistula at 7 post GK-years in one; delayed cyst formation in two, at 5 and 10 post-GK years; and a small cavitation at 9 post-GK years.

CONCLUSION

Long-term follow-up, particularly with neuro-imaging modalities, is essential even after the "treatment goal" has been attained.

Purification and characterization of Microcystis aeruginosa (freshwater cyanobacterium) lectin

Microcystis aeruginosa, strain M228, a laboratory culture of freshwater cyanobacterium, showed hemagglutinating activity against rabbit, horse and human ABO erthrocytes. Crossed absorption tests revealed the presence of a single type of lectin in the extract of M228 strain cells. The lectin, termed MAL, was purified in combination with the affinity chromatography on acid-treated agarose gel and the gel permeation chromatography in an electrophoretically pure form. MAL was a glycoprotein containing 7.8% neutral sugars and was composed of a single polypeptide having a molecular weight of 57 kDa. Isoelectric point was estimated to be pH 6.4. Hemagglutinating activity of the lectin was inhibited effectively by N-acetyl-D-galactosamine and by glycoproteins. D-galactose and lactose also showed moderate inhibitory activity. The destruction of the hemagglutinating activity by a 2-mercaptoethanol treatment suggests the presence of intra-chain disulfide bond(s) essential for the activity in the molecule. The sequence of the amino-terminal region of MAL was determined as Val-Leu-Ala-Ser-Leu-Val-Ser-Thr-Ser-Gln-Ala-Gly-Ser-Leu-Glu-Leu-Leu- Ala [corrected].

Development of a 3D CT-scanner using a cone beam and video-fluoroscopic system

We describe the design and implementation of a system that acquires three-dimensional (3D) data of high-contrast objects such as bone, lung, and blood vessels (enhanced by contrast agent). This 3D computed tomography (CT) system is based on a cone beam and video-fluoroscopic system and yields data that is amenable to 3D image processing. An X-ray tube and a large area two-dimensional detector were mounted on a single frame and rotated around objects in 12 seconds. The large area detector consisted of a fluorescent plate and a charge coupled device (CCD) video camera. While the X-ray tube was rotated around the object, a pulsed X-ray was generated (30 pulses per second) and 360 projected images were collected in a 12-second scan. A 256 x 256 x 256 matrix image was reconstructed using a high-speed parallel processor. Reconstruction required approximately 6 minutes. Two volunteers underwent scans of the head or chest. High-contrast objects such as bronchial, vascular, and mediastinal structures in the thorax, or bones and air cavities in the head were delineated in a "real" 3D format. Our 3D CT-scanner appears to produce data useful for clinical imaging and 3D image processing.

A diffuse white matter ischemic lesion appearing 7 years after stereotactic radiosurgery for cerebral arteriovenous malformations: case report

OBJECTIVE AND IMPORTANCE

Little information is available about radiation-induced complications occurring more than 5 years after radiosurgical treatment for arteriovenous malformations.

CLINICAL PRESENTATION

We present a patient with arteriovenous malformations who experienced hemimotor weakness caused by a diffuse white matter necrotic lesion developing 7 years after gamma knife radiosurgery. The original nidus had been too large (24.1 cm3) to be totally covered and irradiated with a peripheral dose of 20 to 25 Gy. Therefore, the lower half of the nidus, which was adjacent to the major feeding artery, had been partially covered with a 30% isodose volume using two target points with an 18-mm collimator. A central dose of 70 Gy was used to obtain 21 Gy at the periphery. Complete nidus obliteration was angiographically confirmed 38 months after radiosurgery. After a 6-year uncomplicated period, this patient experienced a convulsive seizure and then mild right hemiparesis.

INTERVENTION

Computed tomography demonstrated a diffuse hypodense area in the left white matter, which had not been revealed by the previous examination. With steroid treatment, this patient achieved clinical improvement, although there was no significant improvement in the computed tomography-demonstrated white matter lesion.

CONCLUSION

Although the evaluation of this patient may not be sufficient and further examinations may be necessary, we tentatively conclude that the computed tomography-demonstrated hypodense lesion in this patient is a radiation-related necrotic lesion. Long-term follow-up is crucial, even after the "treatment goal" has been achieved.

Up-regulation of ganglioside biosynthesis, functional synapse formation, and memory retention by a synthetic ceramide analog (L-PDMP)

To address the role of brain gangliosides in synaptic activity, the ceramide analogs, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) and its enantiomer, L-PDMP, were used to inhibit and stimulate ganglioside biosynthesis in cultured cortical neurons. Prolonged treatment with both PDMP isomers exhibited opposite effects on functional synapse formation measured by spontaneous synchronized oscillatory activity of intracellular Ca2+ between the neurons: suppression by D-PDMP and facilitation by L-PDMP. Up-regulation of synaptic activity by L-PDMP could be correlated with the slow but robust stimulation of ganglioside biosynthesis through activating GM3, GD3 and GQ1b synthases. In a similar time course, the activity of p42 mitogen-activated protein kinase was also enhanced by L-PDMP. To evaluate the efficacy of this drug in long-term memory, rats were trained for 2 weeks using an 8-arm radial maze task, and then forebrain ischemia was induced by 4-vessel occlusion. Treatment with L-PDMP starting 24 hours after the transient ischemia ameliorated the deficit of a well-learned spatial memory, demonstrating the potential therapeutic intervention of the ceramide analog for neurodegenerative disorders.

Middle cerebral artery stenosis caused by relatively low-dose irradiation with stereotactic radiosurgery for cerebral arteriovenous malformations: case report

OBJECTIVE AND IMPORTANCE

There have been occasional reports of stenosis or occlusion of major cerebral arteries occurring several years after stereotactic radiosurgery for cerebral arteriovenous malformations. Nevertheless, little information is available regarding the actual irradiation dose to which the affected artery had been exposed.

CLINICAL PRESENTATION

We present a patient with arteriovenous malformations who, although asymptomatic, developed remarkable stenosis of the middle cerebral artery trunk (M1) 3 years after gamma knife radiosurgery. The nidus was covered with a 50% isodose volume. A central dose of 36 Gy was used. A gradual decrease in nidus volume had been suggested by 1- and 2-year postradiosurgical neuroimaging examinations. Three-year postradiosurgical angiography revealed severe segmental stenosis of the M1, as well as remarkable nidus shrinkage.

INTERVENTION

The actual irradiation dose delivered to the affected portion of the artery, as retrospectively determined using a highly accurate three-dimensional analysis technique, was estimated to be 5.1 to 9.8 Gy.

CONCLUSION

This case suggests that a normal major artery, if located close to the target volume, may be affected by low-dose irradiation (10 Gy or even slightly less) delivered with radiosurgery, although a decrease in blood flow through the M1 because of nidus shrinkage or associated stenosis of the distal middle cerebral artery, as well as other unknown factors, may also contribute to proximal M1 stenosis.

Spontaneous regression of primary intracranial germinoma. A case report

BACKGROUND

Testicular seminomas are well known to regress spontaneously at a higher incidence than other tumors. To date, there have been no reports of spontaneous regression of an intracranial germinoma, although these tumors are histologically identical to testicular seminomas.

METHODS

The authors present a patient with a primary intracranial germinoma that regressed spontaneously.

RESULTS

A 21-year-old man was admitted to the study facility with acute onset of headache and vomiting. He had a 3-year history of polydipsia and polyuria. Computed tomography (CT) demonstrated a large tumor in the third ventricle, accompanied by hydrocephalus. He underwent ventriculoperitoneal shunt placement on the second day of hospitalization. A CT scan obtained on the fifth postoperative day demonstrated a remarkable decrease in tumor size. Because serial magnetic resonance imaging (MRI) demonstrated a gradual decrease in tumor size, tumor resection was not performed at that time. The patient was discharged and followed with MRI. The tumor continued to regress for more than 2 months. The patient was readmitted due to tumor regrowth, confirmed by MRI 4 months after the initial admission, despite the absence of symptom exacerbation. Two weeks later, the suprasellar portion of the tumor was resected through a right frontotemporal craniotomy. The histopathologic diagnosis was a germinoma. No concurrent tumors were found on whole body examination. The residual tumor gradually regressed after conventional radiation therapy and there has been neither tumor recurrence nor metastasis to date.

CONCLUSIONS

Although the precise cause of the transient partial regression is unknown, this case indicates that, like their testicular counterparts, intracranial germinomas may on occasion spontaneously regress.

Tumor cell counting using an image analysis program for MIB-1 immunohistochemistry

A cell counting method for MIB-1 immunohistochemistry, using an image analysis program, NIH Image, on a personal computer, has advantages over manual cell counting by microscopy. MIB-1 slides were photographed at a magnification of x 50 on 24 x 36 mm color films and the photographs were then enlarged to adequate size for observation. The MIB-1-positive cells, on the enlargements, were marked with a white pen, and negative cells with a black pen. Subsequently, the image of an enlargement was converted into data that can be processed by the program using a flatbed image scanner. Threshold levels were adjusted according to the respective white and black markings, and the program automatically counted the number of MIB-1-positive and negative tumor cells. Our method has the following significant advantages: Once cells had been marked and the image converted into the NIH Image data, the cell count process was completed within a few minutes; in contrast to manual microscopic cell counting, count overlapping or cells missed by the observer are eliminated; overlapping nuclei could be separated by the marking procedure; our method required no elaborate and costly image analysis system. The present method may be recommended to researchers undertaking cell kinetic studies utilizing immunohistochemical methods.

MIB-1 staining index and peritumoral brain edema of meningiomas

BACKGROUND

Growth rates and tumor aggressiveness of meningiomas are thought to be closely related to brain edema development. However, histopathologic data alone are not consistently accurate predictors of the behavior and clinical course of a meningioma.

METHODS

The authors examined 57 histologically proven intracranial meningiomas to identify factors, including growth fractions determined by MIB-1 immunostaining, that may influence the development of meningioma-associated peritumoral brain edema. There were 54 benign, 2 atypical, and 1 anaplastic meningiomas. The MIB-1 staining index (SI) percentage was defined as the number of MIB-1 positive cells divided by the total number of tumor cells in a 1.037-square millimeter area on the slide. The extent of peritumoral brain edema was determined using preoperative magnetic resonance imaging. The extent of edema was classified as Grade 0,1, or 2 (GR0, GR1, or GR2), in order of increasing severity.

RESULTS

The MIB-1 SIs of the 57 cases ranged from 0.06-6.8% (median, 0.80%). There were 26 GR0, 20 GR1, and 11 GR2 edema cases. The MIB-1 SI rose in order of increasing edema severity. There was a statistically significant correlation between the MIB-1 SI and the extent of brain edema (P<0.0001), and also between the tumor size and the extent of brain edema (P=0.001). Meningothelial and atypical/anaplastic meningiomas were associated with peritumoral brain edema more often than any other subtype (P<0.005).

CONCLUSIONS

Growth fractions, as determined by MIB-1 immunostaining, rise with increasing severity of peritumoral brain edema, indicating a close relationship between tumor aggressiveness and edema development.

Perioperative antimicrobial prophylaxis in neurosurgery: clinical trial of systemic flomoxef administration and saline containing gentamicin for irrigation

The efficacy of a new protocol consisting of a prophylactic antibiotic regimen of peri- and postoperative intravenous administration of flomoxef and irrigation of the operative field with saline containing gentamicin was assessed by comparing infection rates in two consecutive series of patients who underwent neurosurgical procedures. Group A received postoperative flomoxef administration, with saline containing no antibiotics for irrigation, from July 1988 to December 1989. Group B received the new protocol from January 1990 to December 1991. For further evaluation, this protocol was continued in most patients who underwent surgery from January 1992 through December 1993 (Group C). Only adult or adolescent patients who underwent clean neurosurgical procedures were included. The number of patients and procedures in each group were: 76 patients (97 procedures) in Group A, 103 (133) in Group B, and 107 (137) in Group C. There were no significant differences between Groups A and B in age, sex, clinical category, coexistent disease, clinical outcome, surgical procedures, general anesthesia, emergency operation, steroid administration, and the timing (season), duration, and frequency of surgery. Meningitis developed in three patients and subcutaneous infection in one in Group A. None of the patients in Group B experienced postoperative infection. This difference in infection rates (4.1% vs. 0%) was statistically significant (p = 0.0305). Furthermore, no postoperative infections developed in the Group C patients. The most appropriate interval for multiple dose administration was determined by analyzing intraoperative time-related changes in the serum flomoxef concentration during surgery in 21 recent patients. Serum flomoxef concentrations fell below therapeutic levels (3.0 micrograms/ml) by the 6th post-administration hour in 70% of patients. We conclude that this antibiotic regimen significantly reduces the postoperative infection rate following neurosurgical procedures. Multiple dose administration of flomoxef is recommended when the duration of surgery is 6 hours or more.

Gamma knife radiosurgery for brain tumors: postirradiation volume changes compared with preradiosurgical growth fractions

The postradiosurgical volume changes were compared with preradiosurgical growth fractions defined as the tumor doubling time and/or MIB-1 staining index in 14 patients who underwent gamma knife radiosurgery for treatment of various brain tumors. The mean preradiosurgical observation period using neuroimaging techniques was 750 days (range 80-2967 days), and the mean follow-up period after radiosurgery was 664 days (range 328-1100 days). There were four neurinomas, three meningiomas, two craniopharyngiomas, two gliomas, one hemangioblastoma, one pituitary tumor, and one intracranially infiltrative lacrimal gland tumor. The mean patient age at the time of radiosurgery was 52 years (range 8-81 yrs). There were eight males and six females. Following gamma knife radiosurgery, the mean tumor half time was estimated to be 789 days (range 124-2101 days), and the volume reduction against the preradiosurgical tumor volume ranged from 6.3% to 76.1%. This study demonstrates that gamma knife radiosurgery can control tumor growth despite the lack of a correlation with preradiosurgical tumor growth or staining indices for MIB-1. Analyses of this type are essential to show that an "unchanged tumor volume" as demonstrated by postradiosurgery follow-up neuroimaging can be regarded as showing successful radiosurgery.

Gamma knife radiosurgery for arteriovenous malformations: long-term follow-up results focusing on complications occurring more than 5 years after irradiation

The detailed long-term follow-up results of 40 patients treated for cerebral arteriovenous malformations with gamma knife radiosurgery are presented, with special reference to postradiosurgical complications that can develop many years after irradiation. The follow-up period after radiosurgery was 54 to 205 months, excluding one mortality, with a mean and a median of 106 and 97 months, respectively. One patient (2.5%) has, to date, refused all neuroimaging follow-up examinations. Complete nidus obliteration was angiographically confirmed in 26 patients (65%) between 1 and 5 years after radiosurgery. In the remaining 13 patients (32.5%), although significant shrinkage of each nidus was angiographically demonstrated, complete obliteration was not attained during a 3- to 7-year period of follow-up after radiosurgery. Among these 13 patients, 1 underwent surgical extirpation of the nidus and 5 underwent second courses of gamma knife radiosurgery between 3 and 6 years after initial treatment; in 3 of the 5 patients, complete nidus obliteration was angiographically confirmed between 1 and 3 years after the second course of radiosurgery. There were no radiation- or arteriovenous malformation-related mortalities. However, we did experience one angiography-related mortality. We also experienced one morbidity (probably caused by hemorrhagic stroke), which developed 5 years after 2-year postradiosurgical angiography had demonstrated complete obliteration, and three radiation-related morbidities, two of which (hemiparkinsonian syndrome and visual field disturbances caused by delayed cyst formation) occurred 5.5 and 7 years, respectively, after irradiation. Furthermore, we observed another two patients who, although asymptomatic to date, showed delayed cyst formation on magnetic resonance imaging 5 and 10 years after irradiation, respectively. In total, 3 (23%) of 13 patients who underwent computed tomography and/or magnetic resonance imaging more than 5 years after radiosurgery showed delayed cyst formation. In conclusion, long-term follow-up, particularly with the use of neuroimaging techniques, is necessary even after the treatment goal has been achieved.

Radiosurgery for acoustic neurinoma with rapid growth and relatively high staining indexes for proliferating cell nuclear antigen and MIB-1

A 54-year-old female presented with a rapidly growing acoustic neurinoma. The tumor doubling time was 216 days or less before surgery and staining indexes for proliferating cell nuclear antigen (PCNA) and MIB-1 were relatively high (4.1% and 2.1%, respectively). The tumor was partially removed, but regrowth was detected with a tumor doubling time of 205 days. She underwent gamma knife radiosurgery for the residual tumor. The periphery of the tumor was irradiated with a dose of 15 Gy. Magnetic resonance imaging 30 months later demonstrated significant tumor shrinkage. The tumor half time following irradiation was determined to be 401 days. Neither surgery nor radiosurgery produced any additional neurological deficit or complications. Gamma knife radiosurgery can control neurinoma growth even when the tumor shows rapid growth and a relatively high growth fraction indicated by high staining indexes for PCNA or MIB-1.

Comparison of early and late start of antihypertensive agents and baroreceptor reflexes

Along with arterial blood pressure reduction, maintenance of the integrity of baroreceptor reflex function contributes to preserving end-organ function in the treatment of hypertensive patients. The purpose of this study was to investigate the effects of antihypertensive agents (trichlormethiazide, atenolol, nicardipine, and enalapril) on baroreceptor reflex function by comparing early and late starts of treatment. We administered each agent to spontaneously hypertensive rats (SHR) as early-start groups from 10 to 36 weeks of age and as late-start groups from 28 to 36 weeks of age. We evaluated the gain of the reflex control of renal sympathetic nerve activity and heart rate using ramp infusions of phenylephrine and nitroglycerin in untreated SHR at 10, 28, or 36 weeks of age and in treated SHR at 36 weeks of age. In 28- and 36-week-old untreated SHR, the renal sympathetic nerve activity gain was not altered and the heart rate gain was decreased (from -2.3 +/- 0.3 to -1.3 +/- 0.3 and -1.2 +/- 0.3 beats per minute [bm]/mm Hg, P < .05, respectively) compared with 10-week-old SHR. Early and late start of therapy produced arterial pressure reductions (-18 +/- 4 and -12 +/- 5 mm Hg, P < .05, respectively). In the early-start groups, the renal sympathetic nerve activity gain was improved markedly in nicardipine- and enalapril-treated SHR (-4.2 +/- 0.2% and -4.9 +/- 0.2% of control/mm Hg, P < .01, respectively), and the heart rate gain was improved markedly in atenolol- and enalapril-treated SHR (-4.1 +/- 0.2 and -4.4 +/- 0.2 bpm/mm Hg, P < .01, respectively). In the late-start groups, the renal sympathetic nerve activity gain was improved moderately in nicardipine- and enalapril-treated SHR (-3.8 +/- 0.2% and -2.9 +/- 0.2% of control/mm Hg, P < .05, respectively). The heart rate gain was improved slightly only in nicardipine-treated SHR (-1.9 +/- 0.2 bpm/mm Hg, P < .05). These results demonstrate that an early start of antihypertensive treatment improves baroreceptor reflex function markedly compared with a late start of treatment. This supports the hypothesis that a possible critical phase sensitive to intervention with antihypertensive treatment exists during the development of hypertension and indicates that the early start of antihypertensive treatment would be required in clinical practice.

Neuroimaging studies of postobliteration nidus changes in cerebral arteriovenous malformations treated by gamma knife radiosurgery

BACKGROUND

Following radiosurgical treatment, the majority of patients with arteriovenous malformations (AVMs) are periodically examined by means of computed tomography (CT) and magnetic resonance imaging (MRI) to assess the attainment of nidus obliterations, as well as adverse radiation effects in the surrounding brain. However, few neuroimaging studies of the long-term results following complete obliterations, confirmed by angiography, have been published to date.

METHODS

CT, MRI, magnetic resonance (MR) angiographic and angiographic images, obtained after angiographic confirmation of complete nidus obliteration, were reviewed in 11 AVM patients treated with gamma knife radiosurgery. The period between angiographic confirmation of nidus obliteration and these most recent examinations was 12-84 months (mean, 29 months).

RESULTS

In ten patients who were assessed by CT, the obliterated nidus was shown to be isodense (eight cases). A significant time-related decrease in contrast enhancement was observed within 1 to 2 postobliteration years (five/seven cases). Eight patients were evaluated by MRI. On T1-weighted imaging, the nidus was shown to be hypointense (six cases) or a mixture of hypointense and isointense areas (two cases). On T2-weighted imaging, nidus intensity varied more than than observed on T1-weighted imaging, and time-related intensity increases were observed (two/seven cases). No flow-signal void was demonstrated in any of these cases. In four of the seven cases, in which serial postobliteration follow-up MRI studies were conducted, significant gadolinium enhancement persisted 3 years or more after obliteration (maximum of 7 years). No vascular abnormalities were demonstrated in seven patients who were assessed by conventional angiography and/or MR angiography.

CONCLUSIONS

Radiosurgery-induced changes in a nidus may continue for several years after angiography has shown complete AVM obliteration.