The Effect of Overlap between Monomers on the Determination of Fractal Cluster Morphology

Diffusion limited cluster aggregate (DLCA) morphology is studied as a function of monomeric particle overlap for finite sized clusters. The morphology is parameterized by both the fractal dimension D and the prefactor k0. For clusters created on a three-dimensional cubic lattice we find D = 1.80 ± 0.03 and k0 = 1.30 ± 0.07 when the spherical monomers are in point contact. Both these values increase as overlap increases. Also presented is an analysis of the two-dimensional projection of these clusters in order to facilitate electron micrograph images of real clusters. Quantitative relations between actual three-dimensional cluster parameters such as cluster radius of gyration, fractal dimension and number of monomers per aggregate, and measurable two-dimensional quantities such as longest lengths and projected area are given as a function of monomer overlap. Relationships between lengths can be explained only by use of the proper density correlation function and accounting for cluster anisotropy. Finally, we make an unsuccessful attempt to find the source of recent experimental discrepancies in the prefactor k0 in terms of a possible unknown degree of overlap. Copyright 1997Academic Press

Mitochondrial acyl carrier protein is involved in lipoic acid synthesis in Saccharomyces cerevisiae

The yeast gene, ACP1, encoding the mitochondrial acyl carrier protein, was deleted by gene replacement. The resulting acp1-deficient mutants had only 5-10% of the wild-type lipoic acid content remaining, and exhibited a respiratory-deficient phenotype. Upon meiosis, the lipoate deficiency co-segregated with the acp1 deletion. The role of ACP1 in long-chain fatty acid synthesis was studied in fast and fas2 null mutants completely lacking cytoplasmic fatty acid synthase. When grown on odd-chain (13:0 and 15:0) fatty acids, these cells showed less than 1% of C-16 and C-18 acids in their total lipids. Mitochondrial ACP is therefore suggested to be involved with the biosynthesis of octanoate, a precursor to lipoic acid.

Anal fissure. 20-year experience

PURPOSE

This study was designed to review a 20-year experience of the treatment of patients with anal fissure to identify possible etiologic factors and to explore effective preventative measures and the ideal treatment for this disease.

METHODS

From January 1972 to December 1991, 1,391 patients (700 males, 691 females; average age, 39 years) with chronic symptomatic anal fissures underwent surgical treatment using either open or closed techniques. The following procedures were performed: 1) internal sphincterotomy for 1,313 idiopathic fissures; 2) C-anoplasty for 36 cases of anal stricture; 3) debridement and sphincterotomy for 25 patients with postsurgical nonhealing wounds; 4) bilateral excision of the protruding internal sphincter for 17 patients with "subluxation." Acute superficial anal fissures were treated conservatively, with emphasis on anal hygiene.

RESULTS

Acute superficial and fissures responded well to conservative management. Over 95 percent of patients with chronic anal fissures treated by surgery had satisfactory relief of symptoms. Early complications included urinary retention (1.4 percent), bleeding (1.1 percent), and abscess and fistula formation (0.7 percent). Late complications manifested as flatus and liquid incontinence (1.5 percent), delayed wound healing (1.4 percent), recurrence of fissures (1.3 percent), and symptomatic itching and burning (1.1 percent). The complication rate was higher in the group that underwent closed sphincterotomy than in the group treated by open techniques.

CONCLUSIONS

Proper and hygiene is important in both prevention and initial conservative management of symptomatic anal fissures. For chronic intractable cases, open lateral internal sphincterotomy is strongly recommended. C-anoplasty should be done when strictures are present. Excision of the protruding internal sphincter is recommended in patients who present with an excessively elongated, tight anal canal with a partially protruding internal sphincter.

Anatomy of the external anal sphincter

The anatomy fo the external anal sphincter has been studied in 48 adult cadaveric and surgical specimens by anatomical dissection and histological sections in three-dimensional planes. The bilaminar and trilaminar concepts of external anal sphincteric anatomy are reviewed. The significant anatomical differences in the anterior portion of the external sphincter compared with the lateral and posterior portion are emphasized. The different configuration of the anterior part of the external sphincter in men and women is described. A new terminology is proposed, ‘superficial compartment’ (subcutaneous and superficial) and ‘deep compartment’ (deep and puborectalis), on the basis of the close anatomical relationship between each of these two pairs of muscles.

BOTOXR delivery by iontophoresis

We report two patients with severe palmar hyperhidrosis who responded to BOTOX delivered not by injection, the usual method of delivery, but by iontophoresis. The Botulinum molecule has been considered too large for delivery into the skin this way. However, other large peptides, both non-ionic and cationic, have been delivered successfully by this method, so we suspected that BOTOX could in fact be iontophoresed. Our saline-controlled treatment of these two patients with a small iontophoresis unit (Iomed Phoresor II) allowed small volumes of standard BOTOX dilutions to be used, and demonstrates that iontophoresis can indeed deliver BOTOX successfully. This has important therapeutic potential for the large number of patients with focal hyperhidrosis. They may be spared painful injections, and in more severe cases, invasive surgery.

Abnormal first-trimester ductus venosus blood flow: a risk factor for adverse outcome in fetuses with normal nuchal translucency

OBJECTIVES

First-trimester nuchal translucency thickness (NT) is a potent tool for assessment of fetal risks of aneuploidy and other adverse outcomes. When NT is increased, Doppler assessment of the ductus venosus (DV) enhances the prediction specificity for Down syndrome. This study assessed abnormal Doppler DV waveform as a predictor of adverse outcome when the NT is normal.

METHODS

This was a case-control study of 2,505 consecutive patients undergoing NT screening in our certified first-trimester screening program. First-trimester Doppler assessment of DV was performed and atrial systolic velocity was rated as antegrade (normal) or absent/reversed (DV-RAV; abnormal). Each case with normal NT (< 95(th) percentile) and DV-RAV was matched with two controls with respect to maternal age within 1 year, NT within 0.2 mm, crown-rump length within 3 mm, and closest calculated aneuploidy risk. Outcomes for paired variables were compared using t-test and Chi-square test.

RESULTS

Forty-seven (1.9%) patients had normal NT and DV-RAV. After exclusion of three cases with obvious first-trimester anomalies and two with incomplete outcome data, 42 remained for analysis. Adverse outcome included cardiovascular defects (n = 6), fetal growth restriction (n = 3), renal anomaly (n = 2), aneuploidy (n = 3) and multiple defects (n = 3), in a total of 11/42 cases (26.2%). Cardiac abnormalities, renal abnormalities and perinatal death were all significantly more common in the study group (all P < 0.05).

CONCLUSIONS

Abnormal first-trimester DV Doppler findings appear to predict adverse outcome independently of a normal NT. These patients need detailed mid-trimester assessment of fetal anatomy with formal echocardiography, and subsequent follow-up.

(-)-Deprenyl alters the survival of adult murine facial motoneurons after axotomy: increases in vulnerable C57BL strain but decreases in motor neuron degeneration mutants

The effect of (-)-deprenyl on the survival of axotomized adult murine facial motoneurons was investigated. Previously, (-)-deprenyl was shown to increase the number of rat facial motoneurons (FMns) surviving after axotomy at postnatal day 14, apparently by compensating for the loss of muscle-derived trophic factor. In the present study, three different strains of adult mice--A/J, C57BL/6J, and a congenic substrain of the C57BL/6J mice, the C57BL/Mnd mutants--underwent unilateral facial nerve transection. FMns were counted from serial sections taken through the entire length of the facial nuclei ipsilateral and contralateral to the facial nerve transections in animals sacrificed 21 days after axotomy. Subgroups of C57BL/6J and Mnd mutants were treated with either saline or 1.0 mg/kg (-)-deprenyl for 21 days. Another subgroup of Mnd mutants were treated with the metabolites of (-)-deprenyl, a mixture of (-)-amphetamine and (-)-methamphetamine, at a dosage equimolar to 1.0 mg/kg (-)-deprenyl. The number of surviving facial motoneurons in the A/J strain was 90% of unlesioned, control values which supports previous findings that adult FMns receive adequate trophic support and thus can survive loss of muscle-derived trophic support. In the C57BL/6J strain, the facial motoneuron survival was 35% and (-)-deprenyl increased the survival to 50.5%. Mnd mutants showed 62.4% survival; however, (-)-deprenyl decreased the number of motoneurons to 54.9% and amphetamine and methamphetamine treatment further decreased the motoneuron survival to 41.1%. These findings show that FMns in the Mnd mutants and their parental strain, C57BL/6J mice, show greater vulnerability to axotomy as compared to other adult strains of mice. The vulnerability is similar to that found in early postnatal life. (-)-Deprenyl increases the survival of the axotomized C57BL/6J FMns but its major metabolites, (-)-methamphetamine and (-)-amphetamine, further decrease FMn survival in the C57BL/Mnd mutants, possibly due to the induction of neurotoxic proteins causing programmed neuronal death. The efficacy of (-)-deprenyl in increasing the survival of damaged neurons would be expected to decrease as dosage increased above the dosage sufficient to induce maximum neuronal rescue (approximately 0.01 mg/kg) but would decrease as the dosage exceeded that necessary to produce toxic concentrations of the metabolites of (-)-deprenyl (1.0 mg/kg in this study).

Physiologic pineal region, choroid plexus, and dural calcifications in the first decade of life

BACKGROUND AND PURPOSE

Calcifications of the pineal, habenula, choroid plexus, and dura are often physiologic. In the modern CT era with thin-section images and multiplanar reformats, intracranial calcifications have become more conspicuous. We aimed to discover the CT prevalence of pineal region, choroid plexus, and dural calcifications in the first decade of life.

MATERIALS AND METHODS

Five hundred head CTs from different patients (age range, 0-9 years) encountered during a consecutive 6-month period at a single academic children's hospital were reviewed retrospectively after excluding examinations with artifacts and pineal region masses/hemorrhage. All studies were performed on a 320-detector CT, with 0.5-mm collimation and a 512 × 512 matrix. Five-millimeter reformatted axial, sagittal, and coronal images were analyzed for location and extent of intracranial calcifications.

RESULTS

The mean age was 3.5 ± 5.7 years (range, 0-9 years). There were 285 males (57%) and 215 females (43%). Pineal calcifications were present in 5% (n = 25; age range, 3.2-8.9 years; median, 7 years). Habenular calcifications were found in 10% (n = 50; age range, 2.8-8.8 years; median, 7 years). Twelve percent (n = 58) had choroid plexus calcifications, (age range, 0.1-8.8 years). Dural calcifications were rare, present in 1% (n = 6; age range, 2.9-8.7 years).

CONCLUSIONS

Physiologic intracranial calcifications may be found in the first decade, principally in children older than 5 years. Most epithalamic calcifications are habenular. Pineal and habenular calcifications were never present in children younger than 3 and 2 years, respectively. Choroid plexus calcifications may be present in the very young. Dural calcifications are rare.

Surgical treatment of tumors of the distal rectum with sphincter preservation

One hundred one patients with villous adenoma or invasive carcinoma of the distal rectum treated with local excision or coloanal anastomosis were studied. Twenty-three (45%) of the 51 patients with villous adenomas had transanal excision, another 23 (45%) had a posterior proctotomy, and five (10%) had a coloanal anastomosis. Only two patients with a villous adenoma developed a recurrence requiring repeat local excision. Fifteen (30%) of the 50 patients with invasive cancer were treated by transanal excision. All had tumors confined to the submucosa or superficial muscularis. Eighteen (85%) of 21 patients having posterior proctotomy also had tumors with similar depth of invasion. Six (43%) of the 14 patients having coloanal anastomosis had Dukes' B tumors, six (43%) were Dukes' C, and another two (14%) underwent palliative resection. The overall actuarial 5-year survival was 77%. Only four patients treated by transanal excision or posterior proctotomy died of metastatic disease. In the coloanal group, two of 12 patients undergoing curative resection died of recurrent cancer, and another has a pelvic recurrence. Villous adenomas of the distal rectum and selected carcinomas may be treated with local excision and coloanal anastomosis with preservation of sphincter function with good results.

Significance of increased secretion of glucocorticoids in mice and rats injected with bacterial endotoxin

Injection of mice or rats with lipopolysaccharide (LPS) is associated with an increased secretion of glucocorticoids. The high level of mortality following injection of LPS that is noted in adrenalectomized rats can be reversed by dexamethasone or corticosterone. That histamine may be an endogenous mediator of the release of corticosterone caused by LPS is suggested by an attenuation of this corticosterone response by promethazine, an H1 antihistamine. Additional support that LPS-dependent glucocorticoid secretion is mediated, in part, by histamine, is suggested by spleen cell transfer studies revealing differences in the induction of histidine decarboxylase (HDC) synthesis and corticosterone release by the C3H/HeN and C3H/HeJ strains of mice that are differentially sensitive to LPS effects. These and other data on increased levels of histamine and HDC during mitogen-induced lymphocyte blastogenesis, as well as experiments revealing immunomodulatory effects of histamine and histamine agonists and antagonists on lymphocyte blastogenesis, are consistent with the hypothesis that following infection with gram-negative bacteria, the histamine-induced increase in glucocorticoid secretion results in inhibition of HDC in splenocytes, a concomitant attenuation of histamine production, and a resulting return to immune homeostasis.

Blockade of both D1- and D2-dopamine receptors inhibits amphetamine-induced ascorbate release in the neostriatum

In vivo recordings with electrochemically modified microvoltammetric electrodes revealed that several neuroleptic drugs, including haloperidol, clozapine, and thioridazine, blocked the rise in extracellular ascorbate produced by amphetamine in the neostriatum of urethane-anesthetized rats. This effect was also observed in animals that received a combined injection of Sch-23390 and sulpiride, but not when either of these drugs were administered alone or in combination with the 5-HT2 blocker, ritanserin. These results indicate that a combined blockade of D1- and D2-dopamine receptors blocks amphetamine-induced ascorbate release.

Isolation and characterization of a lytic Myoviridae bacteriophage PAS-1 with broad infectivity in Aeromonas salmonicida

To search for candidate control agents against Aeromonas salmonicida subsp. salmonicida infections in aquaculture, one bacteriophage (phage), designated as PAS-1, was isolated from the sediment samples of the rainbow trout (Oncorhynchus mykiss) culture farm in Korea. The PAS-1 was morphologically classified as Myoviridae and possessed approximately 48 kb of double-strand genomic DNA. The phage showed broad host ranges to other subspecies of A. salmonicida as well as A. salmonicida subsp. salmonicida including antibiotic-resistant strains. Its latent period and burst size were estimated to be approximately 40 min and 116.7 PFU/cell, respectively. Furthermore, genomic and structural proteomic analysis of PAS-1 revealed that the phage was closely related to other Myoviridae phages infecting enterobacteria or Aeromonas species. The bacteriolytic activity of phage PAS-1 was evaluated using three subspecies of A. salmonicida strain at different doses of multiplicity of infection, and the results proved to be efficient for the reduction of bacterial growth. Based on these results, PAS-1 could be considered as a novel Aeromonas phage and might have potentiality to reduce the impacts of A. salmonicida infections in aquaculture.

Anoplasty for anal stricture

Twelve patients with anatomic anal stricture were treated with C-anoplasty in the past six years. Anal stricture was caused by previous hemorrhoidectomy in ten, fistulectomy in one, and fissurectomy in one. All patients had had conservative treatment from four to 22 years but failed to respond. Eleven patients obtained satisfactory results from C-anoplasty; one required three anal dilatations postoperatively because of restricture. C-anoplasty is advantageous because it extends the pedicle without compromising vascular supplies; suture-line tension can be controlled by extending the incision; and the size of the graft is easily adjustable to anal size.

Intrastriatal infusions of ascorbate antagonize the behavioral response to amphetamine

Compared to saline, bilateral infusions of ascorbate (AA) into the neostriatum of freely moving rats attenuated rearing, head bobbing, and sniffing at various times after systemic amphetamine administration. Comparable AA infusions into overlying cerebral cortex failed to alter the amphetamine behavioral response. Intrastriatal AA also enhanced the ability of haloperidol to antagonize amphetamine-induced forepaw shuffling and locomotion. Voltammetric measurements in separate animals revealed a linear increase in neostriatal AA that remained within reasonable physiological limits over the course of the AA infusion. Thus, endogenous AA may modulate behavior via mechanisms intrinsic to the neostriatum.

Ovarian endodermal sinus tumor in a postmenopausal woman

BACKGROUND

Ovarian endodermal sinus tumor is rare in postmenopausal women.

CASE

We report the case of a 75-year-old woman with a pure endodermal sinus tumor of the ovary.

CONCLUSION

We believe this to be the oldest patient reported with an ovarian endodermal sinus tumor. The histogenesis of this entity in older patients may be different than when it occurs in young women.

Molecular mechanism of activation and superactivation of Ret tyrosine kinases by ultraviolet light irradiation

The catalytic activities of Ret tyrosine kinases as the products of oncogene RET with multiple endocrine neoplasia type 2A (Ret-MEN2A) or 2B (Ret-MEN2B) mutations and the hybrid gene from c-RET and RFP (Rfp-Ret) were higher than those of c-Ret. We demonstrated that ultraviolet light (UV) irradiation induced activation of c-Ret and superactivation of genetically mutated, and thereby constitutively activated, Ret-MEN2A, Ret-MEN2B, and Rfp-Ret. We found that small proportions of c-Ret and Ret-MEN2B and a large proportion of MEN2A were dimerized due to disulfide bonds and that high kinase activity resided in these fractions. The UV-induced activation of c-Ret and superactivation of Ret-MEN2A and Ret-MEN2B were then shown to be closely associated with promotion of the disulfide bond-mediated dimerization of the Ret proteins. Furthermore, we showed that a large proportion of Rfp-Ret was dimerized or polymerized and that almost all kinase activities resided in the highly polymerized but not dimerized fraction. The UV-induced superactivation of Rfp-Ret was also found to be closely associated with promotion of polymerization but not with dimerization of Rfp-Ret. Further experiments revealed that UV induced intracellular dimerization and activation of the extracellular domain-deleted mutant Ret (Ret-PTC-1). Most importantly, the levels of basal kinase activity and dimerization of Ret-TPC-1-C376A, in which cysteine 376 in the tyrosine kinase domain of Ret-TPC-1 was replaced with alanine, were low and were not increased by UV irradiation. These results suggest that the cysteine at this position works as the primary target of dimerization of Ret proteins inside the cell for both the maintenance of the basal kinase activity and its promotion by UV, possibly in co-operation with the cysteine(s) in the extracellular domain of Ret-MEN2A and Rfp-Ret, which is the target of dimerization and polymerization outside the cell. The potential biological significance of the UV-mediated superactivation of mutant Ret through the newly proposed mechanism in oncogenesis is discussed.

The transsphincteric approach to mild and low rectal villous adenoma: Anatomic basis of surgical treatment

Images

A compartmental model for the ocular pharmacokinetics of cyclosporine in rabbits

Studies were conducted in rabbits to determine the ocular distribution and elimination of cyclosporine, with the objective of developing a comprehensive pharmacokinetic model. Following a bolus dose into the anterior chamber, drug levels were measured in the aqueous humor, cornea, iris/ciliary body, lens, sclera, and conjunctiva. Cyclosporine was rapidly eliminated from the aqueous, but drug levels in ocular tissues persisted for in excess of 48 hours, particularly in the cornea and iris/ciliary body. The terminal elimination half life from these tissues was 45 hr and 30 hr, respectively, providing evidence that these tissues could act as a reservoir for the drug. It was found that a compartmental model accurately described the experimental data. A single compartment was used for each of the tissues and fluids sampled, except for the cornea, which was subdivided into two compartments, representing its tissue and aqueous regions.

Attitudes and perceptions regarding skin cancer and sun protection behaviour in an Irish population

BACKGROUND

Although people seem to be well educated on the harmful effects of the sun, they continue to intentionally expose themselves without adequate protection.

AIMS

To ascertain baseline knowledge regarding skin cancer and review the sun protection behaviours in an Irish population and the effect of doctor-based education on these behaviours.

METHODS

Two hundred participants were recruited for a questionnaire-based study on their perceptions regarding skin cancer and their sun protection behaviour. They were divided into two groups, with one group receiving doctor-based education following the initial survey, and a follow-up questionnaire was carried out within 3 months.

RESULTS

Ninety per cent of participants knew that sun exposure was the major risk factor for skin cancer, and 95% knew that sun beds were not a safe way to tan. Despite this, < 20% used regular sunscreen, and 30% had used or were currently using sun beds in order to tan.

CONCLUSION

Our study indicated that although the participants' knowledge of skin cancer and risk of sun exposure is high, their sun-protective attitudes were not influenced by education in the clinical setting.

Characterization, expression pattern and chromosomal localization of the spermatogenesis associated 6 gene (Spata6)

We report the cloning and characterization of the spermatogenesis associated 6 gene (Spata6) encoding a predicted protein of 488 amino acids. It exhibits similarity with the motor domain of kinesin related proteins and with the Caenorhabditis elegans neural calcium sensor protein (NCS-2). The gene encodes three mRNAs of approximately 2.6, approximately 1.8 and approximately 1.2 kb. The expression of the 2.6 kb mRNA is detected at low levels in testis, ovary, thymus and placenta, while the 1.8 and 1.2 kb transcripts are exclusively expressed in testis. The 1.8 and 1.2 kb transcripts are specifically expressed in haploid germ cells. Data from in situ hybridization experiments suggested that mRNA expression of Spata6 in spermatids is higher than in spermatocytes and spermatogonia. RT-PCR analysis and whole mount in situ hybridization demonstrate that the Spata6 transcript is expressed during embryonic development and is localized in neural tube, somites and limb buds of mouse embryo. The Spata6 gene consists of 15 exons ranging in size between 40 and 596 bp. The 2.6 and 1.8 kb transcripts have different 5' untranslated sequences but have the same translational initiation site and therefore may encode the same protein with a predicted molecular weight of 49.7 kDa. The 1.2 kb transcript is derived from a proximal promoter between exons 7 and 8, and contains a translation initiation codon AUG, which is in frame with initiator AUG codon of the 2.6 and 1.8 kb transcripts. Therefore, the 1.2 kb transcript may code for a truncated protein of 32 kDa. Western blot analysis with the antiserum raised against a synthetic peptide from the C-terminal of the deduced Spata6 protein detects only a single protein of 53 kDa in all tissues studied. The Spata6 gene was localized to chromosome 5, region q34-35 in the rat and to chromosome 1, region p32-35 in the human. In an effort to determine the function of Spata6, we inactivated the mouse gene in embryonic stem cells through homologous recombination. Although the heterozygous mutant cells were able to generate low coat colour chimeric mice, all chimeras did not transmit the targeted allele to their progeny suggesting that a high contribution of Spata6(+/-) cells lead to the lethality of the chimeric embryos.

Clinical association between serum γ-glutamyltransferase levels and the development of insulin resistance in Korean men: a 5-year follow-up study

AIMS

In recent years, γ-glutamyltransferase has emerged as a predictor of cardiovascular disease, Type 2 diabetes mellitus, the metabolic syndrome and hypertension. However, it is not yet certain whether γ-glutamyltransferase is a predictor for insulin resistance. The aim of this study was to examine the longitudinal association between baseline γ-glutamyltransferase level and the development of insulin resistance in Korean men.

METHODS

We performed a prospective cohort study, involving 22 931 healthy Korean men without baseline insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR < 2.7) for 5 years. We checked the HOMA-IR serially to monitor the development of insulin resistance (incidence of HOMA-IR ≥ 2.7). A Cox proportional hazards model was used to determine hazard ratios for insulin resistance by quartile groups of baseline serum γ-glutamyltransferase levels.

RESULTS

During 81 208.6 person-years of follow-up, 3856 (16.8%) cases of insulin resistance developed between 2006 and 2010. After adjusting for multiple covariates, including baseline HOMA-IR, the hazard ratios (95% CI) for incident insulin resistance comparing the second to the fourth quartile of baseline serum γ-glutamyltransferase levels with the first quartile were 1.19 (1.06-1.33), 1.38 (1.23-1.53) and 1.58 (1.41-1.77), respectively (P for trend < 0.001).

CONCLUSIONS

Our findings show that serum γ-glutamyltransferase level could be a predictor of the development of insulin resistance in Korean men.