Hypertrophied Segment Research Articles

Specifics of Left Ventricular Hypertrophy and Characteristic of Phenotypic Variants in Patients with Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is characterized by genetic and phenotypic heterogeneity which manifests in different variants of localization and extent of myocardial hypertrophy.Aim: to evaluate specifics of left ventricular hypertrophy, the prevalence and characteristics of clinical and instrumental features of phenotypic variants of hypertrophic cardiomyopathy.Materials and methods. The study includes 295 patients with hypertrophic cardiomyopathy aged 18 to 88 years (60.3±13.4 years), 183 men (62 %), and women 112 (38 %). The diagnosis of which was established by 2D echocardiography. The severity, localization and extent of myocardial hypertrophy, the maximum thickness of the hypertrophied segment, left ventricular myocardial mass, left ventricular myocardial mass index, the presence and severity of mid-ventricular and left ventricular outflow tract obstruction were evaluated. Depending on the predominant localization and extent of hypertrophy, patients were divided into 8 groups according to the recommendations for hypertrophic cardiomyopathy of the Ministry of Health of the Russian Federation. The analysis and comparison of the obtained results are carried out.Results. The average duration of the disease is 10.5±7.52 years. The mean values of the body mass index in patients — 28.2±2.82 kg/m2. The phenotype with basal hypertrophy of the septum (n=130, 44.1 %), group 1 was most often noted. In 47 (15.9 %) patients, hypertrophy of the septum of “reverse curve” (2 group) was detected, in 41 (13.9 %) — “neutral septum” (3 group), in 36 (12.2 %) — symmetrical hypertrophy of the left ventricle (8 group), 11 (3.7 %) of patients had combined hypertrophy of the septum and other parts of the left or right ventricle (4 group) and the free left ventricular wall (7 group), in 10 (3.4 %) — middle ventricular hypertrophy of the left ventricle (6 group) and in 9 (3.1 %) — apical hypertrophy (5 group). The highest value of the maximum thickness of the myocardium was noted in patients of the 6th group 19.3 (1920.4 mm). Mid-ventricular obstruction was detected in group 6 (90 %), left ventricular outflow tract obstruction was more often registered in groups 4 and 8 (81.8 % and 77.8 %), and less often in group 5 (22.2 %) (p <0.01). In group 7, there were no cases of rest obstruction of left ventricular outflow tract. The maximum values of myocardial mass and left ventricular myocardial mass index were noted in group 8 — 402 (356-439) g and 195 (173218) g/m2, respectively (p <0.01).Conclusion. Echocardiography is an informative tool for assessing the presence, severity myocardial hypertrophy and determination of the phenotypic variant of hypertrophic cardiomyopathy. Variants of septal hypertrophy are most commonly registered one, among which the most frequent is the phenotype of basal septal hypertrophy. Each phenotype of hypertrophic expression is characterized by its echocardiographic parameters.

Reproductive Morphology of the Golden tree snake Chrysopelea ornata (Serpentes: Colubridae) from Ao Nang, Krabi Province, Thailand

We monitored the reproductive morphology of the female and male Golden tree snake, Chrysopelea ornata. The females and males were collected during a year from Ao Nang, Muang Krabi, Krabi province, a southern part of Thailand. We investigated the female and male reproductive systems via anatomical and histological approaches. The results demonstrated that the reproductive tracts of females and males were located above the kidney and its right tract was more anteriorly than the left tract. Ovarian follicles were classified into the previtellogenic, early vitellogenic, and late vitellogenic follicles. Previtellogenic follicles were contained three types of cells in the multi-layered granulosa layer: small, intermediate, and large pyriform cells. This such layer becomes the single layer in which the pyriform cells were disappeared in the vitellogenic follicles. Various stages including corpora lutea, gestation, oviposition, and birth were all observed in this study. The oviductal structure of the Golden tree snake was divided into four regions: anterior and posterior infundibulum, uterus, and vagina. The anterior oviductal wall was covered by ciliated and non-ciliated cuboidal epithelial cells and a thin muscularis layer while its posterior portion was contained by ciliated and non-ciliated cuboidal and columnar epithelial cell, and a thick muscularis layer. We found the tubular ciliated glands in the posterior infundibulum. Additionally, the hypertrophied uterine glands in the uterus were observed during the vitellogenic stage. The seminiferous tubules were active simultaneously with the hypertrophied sexual segment of the kidney.

Focal right ventricular apical hypertrophy or apical muscular ventricular septal defect

A 28-year-old male patient was referred to our imaging center with the differential diagnosis of a right ventricular (RV) apical mass. He was a known case of the ventricular septal defect (VSD) with a history of spontaneous closure at the age of 2 years. His chief complaint was chest pain and palpitation. He was referred with a transthoracic echocardiography report of RV apical hypertrophy with almost apical obliteration or RV apical mass. Cardiovascular magnetic resonance imaging demonstrated few intramyocardial crypts of basal anteroseptal left ventricular (LV) segment. There was no evidence of concomitant LV apical hypertrophy. Indeed, there was a small conical- and tunnel-shaped serpiginous apical-infundibular muscular VSD (3.6 mm RV side's diameter and 7.6 mm LV side's diameter) resulted in a localized and severely hypertrophied RV apical segment and no significant shunt (QP/QS: 1.16). There was no evidence of other cardiac mass.

Value of Anterior Band of the Inferior Glenohumeral Ligament Area as a Morphological Parameter of Adhesive Capsulitis

Objective Thickened inferior glenohumeral ligament (IGHL) is considered as one of the major morphological parameters of adhesive capsulitis (AC). Previous studies reported that the anterior band of inferior glenohumeral ligament thickness (aIGHLT) is correlated with shoulder capsular contracture, luxatio erecta humeri, and AC. However, the thickness varies from the measured angle. To reduce this measurement error, we devised a new morphological parameter, called the anterior band of inferior glenohumeral ligament area (aIGHLA). Methods The aIGHL samples were collected from 54 patients with AC and from 50 control subjects who underwent shoulder magnetic resonance imaging (MRI) without any evidence of AC. Coronal T2-weighted MRI images were obtained at the shoulder level from each patient. We measured the aIGHLA and aIGHLT at the maximal view of the IGHL in the coronal plane using our picture archiving and communication system. The aIGHLA was measured at the whole cross-sectional area of the IGHL in the most hypertrophied segment of the coronal MR images. The aIGHLT was measured at the thickest point of the IGHL. Results The average aIGHLA was 55.58 ± 14.16 mm2 in the control group and 83.71 ± 28.45 mm2 in the AC group. The average aIGHLT was 3.47 ± 0.99 mm in the control group and 4.52 ± 1.02 mm in the AC group. AC patients showed significantly greater aIGHLA (p < 0.001) and aIGHLT (p < 0.001) than control subjects. Receiver operating characteristic (ROC) curve analysis showed that the optimal cut-off score of the aIGHLA was 63.37 mm2, with 79.6% sensitivity, 80.0% specificity, and AUC of 0.84 (95% CI, 0.76–0.92). The optimal cut-off point of the IGHLT was 3.81 mm, with 74.1% sensitivity, 74.0% specificity, and AUC of 0.77 (95% CI, 0.68–0.86). Conclusions Although the aIGHLA and aIGHLT were both significantly associated with AC, the aIGHLA was a more sensitive diagnostic parameter.

Identification of Myocardial Disarray in Patients With Hypertrophic Cardiomyopathy and Ventricular Arrhythmias

BackgroundMyocardial disarray is a likely focus for fatal arrhythmia in hypertrophic cardiomyopathy (HCM). This microstructural abnormality can be inferred by mapping the preferential diffusion of water along cardiac muscle fibers using diffusion tensor cardiac magnetic resonance (DT-CMR) imaging. Fractional anisotropy (FA) quantifies directionality of diffusion in 3 dimensions. The authors hypothesized that FA would be reduced in HCM due to disarray and fibrosis that may represent the anatomic substrate for ventricular arrhythmia. ObjectivesThis study sought to assess FA as a noninvasive in vivo biomarker of HCM myoarchitecture and its association with ventricular arrhythmia. MethodsA total of 50 HCM patients (47 ± 15 years of age, 77% male) and 30 healthy control subjects (46 ± 16 years of age, 70% male) underwent DT-CMR in diastole, cine, late gadolinium enhancement (LGE), and extracellular volume (ECV) imaging at 3-T. ResultsDiastolic FA was reduced in HCM compared with control subjects (0.49 ± 0.05 vs. 0.52 ± 0.03; p = 0.0005). Control subjects had a mid-wall ring of high FA. In HCM, this ring was disrupted by reduced FA, consistent with published histology demonstrating that disarray and fibrosis invade circumferentially aligned mid-wall myocytes. LGE and ECV were significant predictors of FA, in line with fibrosis contributing to low FA. Yet FA adjusted for LGE and ECV remained reduced in HCM (p = 0.028). FA in the hypertrophied segment was reduced in HCM patients with ventricular arrhythmia compared to patients without (n = 15; 0.41 ± 0.03 vs. 0.46 ± 0.06; p = 0.007). A decrease in FA of 0.05 increased odds of ventricular arrhythmia by 2.5 (95% confidence interval: 1.2 to 5.3; p = 0.015) in HCM and remained significant even after correcting for LGE, ECV, and wall thickness (p = 0.036). ConclusionsDT-CMR assessment of left ventricular myoarchitecture matched patterns reported previously on histology. Low diastolic FA in HCM was associated with ventricular arrhythmia and is likely to represent disarray after accounting for fibrosis. The authors propose that diastolic FA could be the first in vivo marker of disarray in HCM and a potential independent risk factor.

First Ever Robotic Stage One ALPPS Procedure in India: for Colorectal Liver Metastases.

Twenty five percent of total liver volume (TLV) is considered as the ideal functional liver remnant (FLR) in major liver resections. In patients with macro-vesicular steatosis, early cirrhosis, and post-neoadjuvant chemotherapy (NACT), hepatocellular injury is common. In such instances, up to 40% of FLR may be required. So in cases of marginal FLR, pre-operative portal vein (PV) embolization or two-stage hepatectomy with PV occlusion is used. Both of which take up to 14weeks between stages and 30% of patients fail to reach the second resection either due to inadequate FLR growth or disease progression. Associated liver partition and portal vein ligation (ALPPS) procedure has become the gold standard for those cases. A 57-year-old male presented with rectosigmoid growth + multiple right liver and segment 4B metastases. Post-NACT MRI showed interval progression of lesions. Preoperative CT (computed tomography) volumetric scan showed a FLR/TLV (future liver remnant/total liver volume) of 22%. Since patient received 10 cycles of NACT, ALPPS procedure was planned ahead of direct liver resection. Robotic ALPPS stage 1 sparing left lateral segment and 4A + anterior resection was done. We transected the parenchyma between the FLR and the diseased part of the liver with concomitant right portal vein ligation done robotically. CT abdomen done on POD7 showed hypertrophied left lateral segment. Second stage was performed on the eighth post-operative day with FLR/TLV increasing to 37%. Robotic ALPPS procedure for stage one is a safe and feasible technique in experienced centers with advanced robotic skills.

Coexistence of apical hypertrophic cardiomyopathy and endomyocardial fibrosis with calcification: diagnosis using multimodality imaging.

A 48‐year‐old man from West Africa was evaluated for dyspnea. Echocardiography showed an echolucent mass at the left ventricular apex surrounded by a dense ridge of tissue, suggesting endomyocardial fibrosis (EMF). Doppler echocardiography showed restrictive hemodynamics and intramyocardial coronary blood flow at the hypertrophied apex, suggesting apical hypertrophic cardiomyopathy (ApHCM) with calcified thrombus. Cardiac magnetic resonance imaging showed a thickened myocardium with apical cavity obliteration and endomyocardial calcification, and gadolinium contrast demonstrated marked bright subendocardial and diffuse patchy intramyocardial hyperenhancement in the hypertrophied apical wall segment, confirming coexistence of EMF and ApHCM. Workup for known disorders of calcification was negative.

The sexual segment of hemidactylus turcicus and the evolution of sexual segment location in squamata

The kidneys of the Mediterranean Gecko, Hemidactylus turcicus (Gekkonidae), were investigated using light and electron microscopy with the primary focus placed on morphology of the sexual segment of the kidney. The nephrons of male H. turcicus are composed of five distinct regions: 1) a renal corpuscle and glomerulus, 2) a proximal convoluted tubule, 3) an intermediate segment, 4) a distal convoluted tubule, and 5) the sexual segment of the kidney/collecting duct. Female H. turcicus is similar but lack a sexual segment of the kidney. The sexual segment of the kidney is hypertrophied during the months of March through August, which corroborates previous reports of reproductive activity. During inactive months, the sexual segment of the kidney is nondiscernable from the collecting ducts. The sexual segment consists of tall columnar epithelial cells with basally positioned nuclei. Perinuclear Golgi complexes and rough endoplasmic reticulum are present. Secretory granules, which fill the apices of the epithelial cells, are electron dense and released into the lumen by a merocrine secretory process. Narrow intercellular canaliculi separate each epithelial cell and are sealed by tight junctions at the luminal aspect. Basally, leukoctyes are observed within the intercellular canaliculi and outside the basal lamina. Mast cells can be found just outside the basal lamina in close association with renal capillaries. The sexual segment of the kidney of H. turcicus is similar to that of three unrelated lizards for which ultrastructure was investigated with secretion mode being the major difference Also, H. turcicus is similar to most other lizards in that complete regression occurs during reproductive inactivity, but differs in this trait from the skink, Scincella lateralis, and most snakes which display a hypertrophied sexual segment of the kidney throughout the entire year. Although some unique similarities appear during the optimization, no direct patterns or directions are observed, and only the molecular based phylogeny resolves the ancestral condition of the Squamata as the sexual segment of the kidney being observed in the distal convoluted tubule, collecting duct, and ureter.

Abnormal Myocardial Capillary Density in Apical Hypertrophic Cardiomyopathy Can Be Assessed by Myocardial Contrast Echocardiography

Myocardial ischemia and dysfunction can occur in hypertrophic cardiomyopathy (HCM) because of the high muscle-to-blood ratio, even without significant coronary artery disease. Microbubbles reside only in the intravascular space and myocardial video-intensity during systole results mostly from microbubbles within capillaries. The hypothesis explored in the present study was that an abnormal capillary density in apical HCM (ApHCM) can be demonstrated using myocardial contrast echocardiography (MCE). The 56 patients were investigated (31 males, age 58 ± 9 years; 33 ApHCM, 9 hypertensive left ventricular hypertrophy [LVH], 14 controls). MCE was performed with low-mechanical-index power modulation imaging. Tissue Doppler imaging to assess myocardial contractile function was obtained at the mitral annulus (S'), and (99 m)Tc-MIBI SPECT was also performed. All ApHCM patients exhibited perfusion defects at the hypertrophied segments in the systolic phase during MCE, whereas SPECT showed normal or rather increased perfusion at those sites. The cyclic variation of video-intensity was exaggerated in ApHCM when compared with the LVH or control group (% of [systolic video-intensity]/[diastolic video-intensity]: 33.0 ± 12.3%, 88.3 ± 19.2% and 79.4 ± 13.9%, respectively [P<0.05]). Concurrently, MCE cyclic variation and perfusion defect size were related to decreased S' (P<0.05 for all). A perfusion defect at the hypertrophied segment, representing abnormal myocardial capillary density, was observed in ApHCM patients during MCE. The extent of MCE cyclic variation and the perfusion defect size both correlate with decreased myocardial contractile property in ApHCM.

A multiyear comparison of the male reproductive biology of the brown treesnake (Boiga irregularis) from Guam and the native range

Previous studies have suggested that reproduction in the brown treesnake (Boiga irregularis) is reduced on Guam because of elevated stress hormones caused by limited food availability. This study examined the reproductive anatomy of male brown treesnakes on Guam over a 15-year period (1985–99) to determine whether the size at maturity and development of the testis and sexual segment of the kidney varied between years and to compare these data to those for snakes collected from the native range. On Guam, the average snout–vent length and body mass of B. irregularis has decreased from its high in 1985 and remained stable from 1989 to 1999. The snout–vent length at maturity was similar between years. Mean diameters of the seminiferous tubule and the sexual segment of the kidney were not significantly different between years. However, the number of sexual segment tubules hypertrophied per snake varied greatly. Snakes from the native range matured at smaller snout–vent lengths and had significantly more hypertrophied sexual segment tubules per kidney than populations on Guam. These data suggest that elevated plasma levels of corticosterone, potentially due to an increase in male–male interactions as a result the explosive population growth experienced on Guam, may be negatively influencing male reproduction.

Ventricular arrhythmias in apical hypertrophic cardiomyopathy: association with late gadolinium enhancement

Methods 26 consecutive patients (pts), aged 38 ± 11 years-old, 15 men, with AHCM, were included. Diagnosis was established by CMR using accepted criteria All underwent complete CMR LV assessment using a 17-segments model: a) SSFP short-axis LV volumes and ejection fraction; b) SSFP 2, 3, 4-chambers for thickness measurement; c) LV segmental LGE (segmented inversion-recovery fast gradientecho sequence, 10-15 mn after 0.2 mmol/kg of Gd-DTP); the presence and amount of LGE was assessed. A 24 hours-Holter monitoring was obtained in less than twoweeks interval and the number of repetitive ventricular arrhythmias was assessed (pairs, triplets, ventricular tachycardia). Results Maximal apical thickness was 21 ± 4 mm (13-30), left ventricular end-diastolic volume was 56 ± 8 ml/m2 (39-73) and ejection fraction was 68 ± 5% (59-80). LGE was detected in 15 pts, localized at the midwall apical region, filling all this segment in 12 pts and nodular in the remaining three. No hypertrophy or LGE was detected in other LV segments. The presence of repetitive ventricular arrhythmias was significantly different in patients with and without LGE (p = 0.0001). Patients with LGE, showed 10 to 143 repetitive episodes in the Holter monitoring. There was no correlation between the number of ventricular arrhythmias and the amount of LGE (LGE volume/ hypertrophied apical segment volume), the apical thickness, LV volume or ejection fraction.

9321 Metastatic uveal melanoma, clinical characteristics and survival: a single center experience on 58 patients

Patients with bilobar colorectal cancer metastases to the liver present a unique problem in terms of resection. They sometimes require a staged approach to resection that takes advantage of the liver's ability to regenerate, as well as the newer chemotherapeutic agents (e.g., oxaloplatin, irinotecan (CPT-11), and bevacizumab) that have become available. In cases of multiple bilobar metastases, if segment IV is clear of tumor, a left lateral segmentectomy (LLS) can be performed, followed several months later by a formal right hepatectomy. The remnant liver composed of the hypertrophied segment IV is drained by the middle hepatic vein (MHV). In this context, patients with lesions between the origin of the MHV and the inferior vena cava (IVC) present a particularly difficult problem. Conventional excision would require an extended hepatectomy and division of the MHV along with either the right or left hepatic veins (RHV, LHV). This would make it impossible to continue with a formal resection of the remaining lesions in the contralateral liver without sacrificing the sole remaining hepatic vein. We present a novel two-step hepatectomy for lesions between the MHV and the IVC that allows the MHV to be preserved and all lesions to be resected.

A case of coronary cameral fistula

An 85-year-old woman underwent transthoracic echocardiography for the investigation of breathlessness and atypical chest discomfort. Clinical examination was unremarkable. A standard 12 lead ECG demonstrated anterior T wave inversion, but was otherwise normal. Transthoracic echocardiography demonstrated a normally functioning left ventricle with hypertrophy and trabeculation of the apical and lateral segments. Imaging with colour flow Doppler demonstrated blood flow from the epicardial surface into the left ventricular cavity through the hypertrophied segment of myocardium during diastole. A diagnosis of multiple, diffuse coronary-left ventricular fistulae predominantly of a large diagonal branch of the left anterior descending artery was made at coronary angiography. The patient responded well to oral beta-blockade, reporting an improvement in symptoms 2 months later in the outpatient clinic. The echocardiographic appearances of coronary fistulae may cause diagnostic confusion, particularly in the presence of myocardial hypertrophy and trabeculation.

Novel Two-Step Resection for Lesions Between the Middle Hepatic Vein and Vena Cava Which Allows the Middle Hepatic Vein to Be Preserved

Patients with bilobar colorectal cancer metastases to the liver present a unique problem in terms of resection. They sometimes require a staged approach to resection that takes advantage of the liver's ability to regenerate, as well as the newer chemotherapeutic agents (e.g., oxaloplatin, irinotecan (CPT-11), and bevacizumab) that have become available. In cases of multiple bilobar metastases, if segment IV is clear of tumor, a left lateral segmentectomy (LLS) can be performed, followed several months later by a formal right hepatectomy. The remnant liver composed of the hypertrophied segment IV is drained by the middle hepatic vein (MHV). In this context, patients with lesions between the origin of the MHV and the inferior vena cava (IVC) present a particularly difficult problem. Conventional excision would require an extended hepatectomy and division of the MHV along with either the right or left hepatic veins (RHV, LHV). This would make it impossible to continue with a formal resection of the remaining lesions in the contralateral liver without sacrificing the sole remaining hepatic vein. We present a novel two-step hepatectomy for lesions between the MHV and the IVC that allows the MHV to be preserved and all lesions to be resected.

Use of pulsed Doppler tissue imaging to assess regional left ventricular diastolic dysfunction in hypertrophic cardiomyopathy

In this study, regional diastolic patterns and their relations with transmitral Doppler inflow were investigated in hypertrophic cardiomyopathy (HC) by pulsed Doppler tissue imaging (DTI). Doppler echocardiography and DTI of basal septum and lateral wall (apical 4-chamber view) were performed in 20 patients (15 men and 5 women) with HC and in 10 healthy subjects (7 men and 3 women). Diabetes, hypertension, coronary artery and valvular disease, mitral regurgitation, New York Heart Association functional classes III to IV, sinus tachycardia, atrial fibrillation, and inadequate echocardiograms were exclusion criteria. Peak velocity and time-velocity integral of early and late waves and their ratios, and deceleration and isovolumic relaxation times were determined by standard Doppler and by DTI at the septal and lateral wall levels. The 2 groups were comparable for age, heart rate, blood pressure, and ejection fraction. Transmitral peak velocity and time-velocity integral E/A ratios were reduced (both p <0.05) and deceleration and isovolumic relaxation times prolonged (both p <0.00001) in HC. Septal DTI showed lower peak velocity and time-velocity integral e/a ratios (p <0.00001 and p <0.001, respectively) and lengthened regional deceleration (p <0.01) and isovolumic (p <0.001) relaxation times. DTI of the lateral wall showed a prolongation of deceleration and isovolumic relaxation times (both p <0.01). By dividing HC according to transmitral E/A, 8 patients with E/A <1 had lower DTI septal e/a ratio (p <0.01) and prolonged septal deceleration and isovolumic relaxation times (both p <0.01) but no changes in DTI pattern of lateral wall than 12 patients with E/A >1. In conclusion, DTI is useful and complementary to standard Doppler imaging to characterize diastolic properties in HC, reflecting a typical pattern of intramyocardial impaired relaxation at the level of hypertrophied septum and also providing information about the degree of this regional impairment. The lateral wall presents minor changes in diastolic times, which indicate how diastolic asynchrony is not confined to the hypertrophied segment in HC.

Hypertrophic Cardiomyopathy and Myocardial Ischemia with Normal Coronary Arteries

The case reported herein illustrates an unusual form of nonobstructive hypertrophic cardiomyopathy which was associated with Wolff-Parkinson-White syndrome, myocardial ischemia and necrosis despite normal coronary arteries. The patient is unique since the hypertrophied myocardial segment was localized exclusively to the posterolateral free wall. Quantitative thallium-201 scintigraphy demonstrated reversible ischemia that corresponded precisely with this region of posterolateral hypertrophy. While the exact mechanism for ischemia in patients with hypertrophic cardiomyopathy and normal coronary arteries remains controversial, a functional rather than anatomic disturbance of blood flow seems likely.

Anomalohimalaya lama, New Genus and New Species (Ixodoidea: Ixodidae), a Tick Parasitizing Rodents, Shrews, and Hares in the Tibetan Highland of Nepal1

ANOMALOHIMALAYA lama, new genus and new species, is described from adults, nymphs, and larvae. This parasite was taken in 3 localities in the Tibetan alpine desert biotope at 12,500 feet altitude in Mustang District of Nepal, first during winter from rodents trapped in snow-covered runways, and later in spring. Hosts were voles, Alticola sp.; field mice, Apodemus sp.; shrews, Sorex sp.; and a woolly hare, Lepus oiostolus subsp. This parasite appears to have evolved from protorhipicephaline stock but to have developed structurally and biologically along a unique line differing significantly from Rhipicephalus and related genera. Thus a new generic category is proposed. Exceptional biological adaptations have been combined with arrested development or progressive degeneration through successive developmental stages of certain characteristic rhipicephaline structures and with hypertrophy of palpal segment 1. The larva is rhipicephalid-like and possesses eyes, but unlike in Rhipicephalus, eyes are lost in the nymph and adult. The male basis capituli resembles that of certain nymphal Rhipicephalus . Lack of both adanal and accessory shields on a crinkly, membranous male ventral integument is unique among rhipicephalid-related genera. The male is exceptionally large in comparison to the female. The adult leg segments distad of the coxae are like those of the nymph rather than the adult Rhipicephalus . The female palpi, as in nymphs, are elongate (short and compact in female Rhipicephalus ). The remarkably hypertrophied adult palpal segment 1 is more or less similar to that of adult and/or immature stages of certain Ixodes species, most of which parasitize small burrowing mammals or marine birds. No adult Rhipicephalus possess an equally hypertrophied palpal segment 1 though a vestige of this adaptation occurs in the nymph of a few species. The palpal structure is discussed. The hypertrophied segment 1 functions are possibly to prevent the elongate hypostome of the relatively large tick from penetrating unfavorably deeply into the small-size host and to permit formation of a large cement cone around the hypostome, thus preventing easy dislodging from the small host of the large, otherwise superficially attached tick. The collecting region, north of the Himalayas, differs ecologically and zoogeographically from the rest of Nepal. Characteristic tick parasites of domestic animals in this highland area are Dermacentor everestianus Hirst and Hyalomma marginatum turanicum Pomerantzev. The former species is recorded from only 1 locality in Nepal outside of Mustang District, the latter is unknown elsewhere in Nepal.

Congenital Megacolon. A Comparison of the Spastic and Hypertrophied Segments with Respect to Cholinesterase Activities and Sensitivities to Acetylcholine, DFP and the Barium Ion

Summary 1.The distal spastic segments and the proximal hypertrophied segments of five fresh surgical specimens of the colon from cases of congenital megacolon have been compared with respect to (a) thresholds of response to acetylcholine (ACh), di-isopropylfluorophosphate (DFP) and BaCl 2 , (b) specific and nonspecific cholinesterase (ChE) activities and (c) the histochemical distributions of the ChE's. 2.The hypertrophied segments had lower thresholds of response to ACh, whereas the thresholds of the two types of segment to DFP and BaCl 2 were practically identical in all cases. The latter observation indicates that BaCl 2 acts directly on the smooth muscle fibers of the human colon rather than on the ganglion cells. 3.Both the specific and non-specific ChE activities were considerably higher in the spastic than in the hypertrophied portions. Histochemical studies indicated that the greater specific ChE activity of the former was associated with the large number of non-myelinated nerve fibers in the ganglion cell-free myenteric plexus. The lower non-specific ChE activity of the hypertrophied segment appeared to be the result of a thinning-out of the muscularis mucosae and other regions where the enzyme is concentrated. 4.The present findings suggest that the chief anatomical abnormalities in congenital megacolon may consist of a central displacement of the cholinergic neurons and an absence or paucity of the adrenergic neurons of the myenteric plexus of the spastic distal segment.