Movements of the large intestine in the anuran larvae, Xenopus laevis

1. The contractile behavior of the large intestine of Xenopus laevis tadpoles was studied. 2. The large intestine is divided into a colon and rectum, and shows three types of movements: rhythmic ascending (antiperistaltic) waves of contraction originating at the anal end of the large bowel, rhythmic longitudinal contractions in the rectum and colon, and irregular contractions. The first two patterns occur in the large bowel in situ and thus appear mature. The last one occurred only in older preparations, and thus appeared pathological. 3. Antiperistaltic waves of contractions and longitudinal contractions are generated independent of each other, suggesting that circular muscles and longitudinal muscles contract separately. 4. Acetylcholine, adrenaline and noradrenaline augment motility. 5. The premetamorphic motility of the large bowel is similar to that seen in adult frogs. Comparable motility was not observed elsewhere in the larval alimentary tract. The large intestine appears to be the first portion of the anuran alimentary tract to acquire the adult physiological and morphological profile.     

Ivermectin inhibits molting of Wuchereria bancrofti third stage larvae in vitro

The effect of ivermectin or diethylcarbamazine (DEC) on Wuchereria bancrofti molting from the third to the fourth larval stage (L3 to L4) was evaluated in vitro. L3 larvae were harvested from laboratory-reared Aedes togoi 2 wk after feeding upon a microfilaremic human volunteer. The larvae were kept in an artificial medium (Franke's NI medium) with 10% human serum under an atmosphere of 5% CO2 for 20 days. Experimental tubes also contained ivermectin (0.1-1,000 ng/ml) or DEC (0.1-10,000 ng/ml). An estimated concentration of 50 ng/ml ivermectin inhibited molting in 50% of the larvae expected to molt. For DEC, this value was roughly 1,000 ng/ml. In this in vitro culture system, ivermectin inhibited the L3 to L4 molt of W. bancrofti and was roughly 20-fold more potent in this activity than DEC.     

Development of Ascaris suum larvae from the third to fourth stage, in vitro

Larvae of Ascaris suum recovered from the lungs of experimentally infected guinea pigs or rabbits, seven to ten days after infection, underwent the third moult in vitro to become fourth-stage larvae. Ecdysis was first observed on the first and second day of culture and was completed by the eighth day. The culture medium consisted of tissue culture Medium 199 supplemented with either guinea pig or porcine serum and glucose in a gaseous atmosphere of Nitrogen:Oxygen:Carbon dioxide (90:5:5). By the twelfth day in culture, early development of both the male and female reproductive systems was observed.     

Immunization of lambs against Oesophagostomum columbianum, using irradiated third stage larvae

The effect of gamma irradiation at doses of 40- and 50 kR on the development of third stage larvae of Oesophagostomum columbianum and the protection conferred by these irradiated larvae against the nematode, was studied in 6-8 week old male Kashmir Merino lambs. At 40- and 50 kR doses, the third stage larvae failed to develop to the adult stage in the intestine. Though single vaccination with 2000, 50 kR irradiated larvae failed to protect the animals against the infection, vaccination with the same number of 40 kR irradiated larvae conferred a partial protection. The presence of adult worms of O. columbianum in sites outside the intestine of 6-8 week old lambs have been demonstrated for the first time.     

Scanning electron microscopy of ciliary zones of the ciliate protozoa in the large intestine of the horse.

The surface structure of the ciliary zone in 13 species of ciliates found in the large intestine of the horse was observed by scanning electron microscopy. In Holophryoides ovalis many fine depressions considered to be a result of phagocytosis or pinocytosis in the naked cytostome were noticed. In Blepharocorys spp. a distinct section was present between the portion with cilia and that without cilia. It was not present, however, in some species of the family Buetschliidae, such as Bundleia postciliata and Didesmis spp. The species of Entodiniomorphida had a lip around the ciliary zone with cilia forming synciliary tufts. In Spirodinium equi and Tetratoxum unifasciculatum the ciliary zone revolved counter-clockwise in an en face view. Some differences in the surface structure of the ciliary zone between the entodiniomorphid and spirotrich ciliates are discussed.     

A third allele in the horse albumin system

Starch gel electrophoresis according to Gahne (1966) reveals three new phenotypes designated FI, I and IS in horse serum albumin. Family material comprising 97 sire families with a total number of 2742 foals and their dams and population material comprising 2867 adult horses representative of the Swedish Trotter breed were examined. The results were consistent with a genetic theory of three codominant, autosomal alleles F, I and S controlling the six albumin phenotypes observed. The gene frequencies were estimated to be 0.489, 0.049 and 0.462, respectively, for the F, I and S genes in the Swedish Trotter breed. The risk of making false exclusions in paternity controls in the albumin system, if the I allele is not considered, is discussed.     

Ontogeny and distribution of certain endocrine cells in the human fetal large intestine

Summary In 9 fetuses, 9 to 24 weeks-old, the occurrence and relative distribution of argentaffin cells, as well as of cells immunoreactive to somatostatin (SRIF), glucagon-like polypeptide (GLI), pancreatic polypeptide (PP) and substance P (SP) were studied in five segments of the colon (appendix, cecum, ascending colon, descending colon, and rectosigmoid). For each colonic segment, data concerned with the occurrence of endocrine cells were expressed either as mean absolute numbers of specific cells per entire mucosal section, or as cell densities per mm³ of mucosa after calculation of the mucosal volume of the sections. Argentaffin, GLI, SRIF and PP immunoreactive cells are all present in relatively large numbers, scattered along the entire length of the colonic mucosa as early as the 9th–10th week of gestation, whereas substance P-containing cells occur sporadically and first appear during the 14th–17th week. Until the 20th week, with progressing embryonic development, an increase was determined in absolute numbers per section of all types of endocrine cells in all segments of the colon. This observation is clearly related to the general growth of the colonic mucosa, since cell densities per mm³ of mucosa do not greatly change or even decrease during gestation. However, it is possible that densities of argentaffin, GLI and BPP cells increase in the appendix around the 14th–17th week of gestation. Between the 20th and 24th week, absolute numbers of cells per section remain stable or slightly increase, while cell densities tend rather to decrease in all segments. These data demonstrate that some endocrine cells are present very early in the human fetal colon, but their functional significance remains to be elucidated.This work was supported by the Institut National de la Santé et de la Recherche Médicale (INSERM)     

The Bristol third stage trial: active versus physiological management of third stage of labour.

OBJECTIVE--To compare the effects on fetal and maternal morbidity of routine active management of third stage of labour and expectant (physiological) management, in particular to determine whether active management reduced incidence of postpartum haemorrhage. DESIGN--Randomised trial of active versus physiological management. Women entered trial on admission to labour ward with allocation revealed just before vaginal delivery. Five months into trial high rate of postpartum haemorrhage in physiological group (16.5% v 3.8%) prompted modification of protocol to exclude more women and allow those allocated to physiological group who needed some active management to be switched to fully active management. Sample size of 3900 was planned, but even after protocol modification a planned interim analysis after first 1500 deliveries showed continuing high postpartum haemorrhage rate in physiological group and study was stopped. SETTING--Maternity hospital. PARTICIPANTS--Of 4709 women delivered from 1 January 1986 to 31 January 1987, 1695 were admitted to trial and allocated randomly to physiological (849) or active (846) management. Reasons for exclusion were: refusal, antepartum haemorrhage, cardiac disease, breech presentation, multiple pregnancy, intrauterine death, and, after May 1986, ritodrine given two hours before delivery, anticoagulant treatment, and any condition needing a particular management of third stage. INTERVENTIONS--All but six women allocated to active management actually received it, having prophylactic oxytocic, cord clamping before placental delivery, and cord traction; whereas just under half those allocated to physiological management achieved it. A fifth of physiological group received prophylactic oxytocic, two fifths underwent cord traction and just over half clamping of the cord before placental delivery. ENDPOINT--Reduction in incidence of postpartum haemorrhage from 7.5% under physiological management to 5.0% under active management. MEASUREMENTS AND MAIN RESULTS--Incidence of postpartum haemorrhage was 5.9% in active management group and 17.9% in physiological group (odds ratio 3.13; 95% confidence interval 2.3 to 4.2), a contrast reflected in other indices of blood loss. In physiological group third stage was longer (median 15 min v 5 min) and more women needed therapeutic oxytocics (29.7% v 6.4%). Apgar scores at one and five minutes and incidence of neonatal respiratory problems were not significantly different between groups. Babies in physiological group weighed mean of 85 g more than those in active group. When women allocated to and receiving active management (840) were compared with those who actually received physiological management (403) active management still produced lower rate of postpartum haemorrhage (odds ratio 2.4;95% CI1.6 to 3.7). CONCLUSIONS--Policy of active management practised in this trial reduces incidence of postpartum haemorrhage, shortens third stage, and results in reduced neonatal packed cell volume.     

Osteological development of the feeding apparatus in early stage larvae of the seabass,Lates calcarifer

The osteological development of the feeding apparatus was examined in early stage larvae of laboratory-reared seabass,Lates calcarifer. At initial mouth openings 40 hours after hatching, the larvae were equipped with the fundamental elements forming the oral cavity, such as the trabecular roof, the lower branchial and hyoid arches forming the floor, the quadrate and symplectic-hyomandibular cartilages making up the sides, and the maxilla and Meckel's cartilage bordering the jaws. The cleithrum appeared almost simultaneously. The mechanics of creating a negative pressure in the oral cavity, which results in a “sucking” mode of feeding, were elucidated from these elements. During a period from 50–60 to 100–110 hours after initial mouth opening (HAMO), new elements such as the premaxilla and jaw teeth appeared, and the ossification of existing elements started. The new elements apparently enabled the larvae to “grasp” food organisms, in addition to the already existing and increasing sucking ability, from 100–110 HAMO.     

The ontogeny of physiological response to temperature in early stage spiny lobster (Jasus edwardsii) larvae

The physiological response to temperature, in terms of oxygen consumption, nitrogen excretion and feed intake was examined in Jasus edwardsii larvae at mid-stages I-III. From stage I to stage III, the mass-specific oxygen consumption increased in a sigmoid pattern over the temperature range of 10-22 degrees C. The Q(10) value declined significantly from 14-18 to 18-22 degrees C range, indicating a reduced temperature dependence of larval metabolism at higher temperatures. At all stages, feed intake increased with increasing temperature but reached a plateau at the higher temperatures for stages I and II larvae. In contrast, nitrogen excretion increased linearly over this temperature range for all larval stages. Therefore, higher temperatures ( approximately 22 degrees C) may cause an energetic imbalance and reduce growth potential in early stage larvae. While the convection requirement index (quotient of feed intake and oxygen consumption) indicated an equivalent metabolic feeding efficiency from 14 to 22 degrees C, a consistent decline of the O/N ratio above 16-18 degrees C from stage I to stage III suggested that exposure to elevated temperatures may result in an increase in the amount of protein being diverted from growth to catabolic processes. Based on these results, a temperature of 18 degrees C is recommended for the culture of early stage J. edwardsii larvae.