The locomotory activity patterns of a functionally complete colony of Cryptomys hottentotus hottentotus (Rodentia: Bathyergidae)

The locomotory activity patterns of a colony of eight field-captured mole-rats housed in a transparent burrow system were monitored for a total of 240 hours. Movement along the burrow system was recorded for all hours of the 24-hour chronological day for 10 days. Intermittent periods of activity were characteristic for all the mole-rats in the colony. The lack of a distinct sleeping period reflects the asynchrony of each mole-rat's activity cycle with that of other colony members. There are four major peaks of activity during the 24-hour cycle and an absence of a well-defined diurnal or nocturnal phase to the activity cycle.
The nest area is a focal point in the burrow system with individuals spending between 36 and 81% of the day there. There is a positive correlation between the size of a group of sleeping mole-rats in the nest and the frequency of occurrence.     

The changes in the dominance hierarchy over time of a complete field-captured colony of Cryptomys hottentotus hottentotus

The common mole-rat, Cryptomys h. hottentotus , is a social subterranean rodent occurring in colonies in which one female and one to three males are involved in reproduction and the remaining colony members are non-reproductive. Within each sex the reproductive animals are usually the largest and most dominant animals.
The dominance hierarchy amongst a field-captured colony was linear ( h = 0.95, calculated from Landau's linearity index) soon after capture. The non-reproductive females were ranked low in the dominance hierarchy; many were subordinate to non-reproductive males. The order of capture of mole-rats was not related to the position in the dominance hierarchy. The hierarchy became non-linear ( h = 0.56) after six months in captivity during which two juvenile animals became adult. The breakdown in the hierarchy may result from the lack of opportunity in captivity for animals to disperse and establish satellite colonies, or from colony members becoming co-dominant in the hierarchy as a result of a rise in rank by young animals.
Dominant mole-rats are involved in a greater proportion of interactive behaviours than subordinates. Popularity studies show that females tend to be more popular animals than males. The largest reproductive male was the least popular animal in the first study, whereas a beta male was the least popular animal in the second study period. The reproductive female was the most popular in both periods.     

Risk of second primary cancers after Hodgkin's disease by type of treatment: analysis of 2846 patients in the British National Lymphoma Investigation.

OBJECTIVE--To analyse the risk of second primary cancers during long term follow up of patients with Hodgkin''s disease. DESIGN--Cohort study. SETTING--The British National Lymphoma Investigation (a collaborative group of over 60 participating centres in Britain treating lymphomas). PATIENTS--2846 patients first treated for Hodgkin''s disease during 1970-87, for whom follow up was complete in 99.8%. MAIN OUTCOME MEASURES--Second primary cancers; uniform pathology reviews confirmed the diagnosis of Hodgkin''s disease and of second primary non-Hodgkin''s lymphomas. RESULTS--113 second primary cancers occurred. Relative risk of cancer other than Hodgkin''s disease was 2.7 (95% confidence interval 2.3 to 3.3) compared with the general population, with significant risk of leukaemia (16.0(9.1 to 26.0)); non-Hodgkin''s lymphoma (16.8(9.8 to 26.9)); and cancers of the colon (3.2 (1.4 to 6.2)), lung (3.8 (2.6 to 5.4)), bone (15.1 (1.8 to 54.7)), and thyroid (9.4 (1.1 to 33.9)). Absolute excess risk associated with treatment was greater for solid tumours than for leukaemia and lymphomas. Relative risk of leukaemia increased soon after treatment, reaching a peak after five to nine years. It was increased substantially after chemotherapy (27.9 (12.7 to 52.9)), combined treatment with radiotherapy and chemotherapy (21.5 (7.9 to 46.8)), and relative to number of courses of chemotherapy but was not significantly increased after radiotherapy (2.5 (0.1 to 14.1)). Relative risk of non-Hodgkin''s lymphoma increased in the first five years after treatment and remained high but showed no clear relation with type or extent of treatment. Relative risk of solid tumours was less raised initially but increased throughout follow up and for lung cancer 10 years or more after entry was 8.3 (4.0 to 15.3). The risk of solid tumours increased after treatments including radiotherapy and after chemotherapy alone. The risk after chemotherapy increased significantly with time since first treatment. CONCLUSION--The risk of solid cancer, not of leukaemia, is the major long term hazard of treatment for Hodgkin''s disease, and this seemed to apply after chemotherapy as well as after radiotherapy. These risks of second cancers are important in choice of treatment and in follow up of patients, but they are small compared with the great improvements in survival which have been brought about by modern therapeutic methods for Hodgkin''s disease.     

Quantitative autoradiographic analysis of [I]-human CGRP binding sites in the dorsal horn of rat following chronic constriction injury or dorsal rhizotomy

Quantitative receptor autoradiography was used to examine the binding of [¹²⁵I]-human CGRP in the dorsal horn of the L4 spinal segment of rats with a chronic constriction injury (CCI) of the sciatic nerve or unilateral dorsal rhizotomies of spinal segments L1–L6. At the times selected for study, we found no change in the amount of CGRP binding in any areas examined following CCI. In contrast, our results showed a temporally related increase in the amount of CGRP binding in areas within laminae I–II and in lateral lamina V of the dorsal horn ipsilateral to the rhizotomies. These results indicate that CGRP binding sites are regulated, most likely, by changes in the release of CGRP. Further, our results suggest that the release of CGRP from primary afferent neurons is unchanged in animals with a CCI.     

Assumption validity in human optimal foraging: The Barí hunters of Venezuela as a test case

Optimal foraging theory is being used increasingly as a means of understanding human foraging behavior. One of the central assumptions of optimal foraging theory is that prey items or patches are encountered sequentially and as a Poisson process. Using empirical data gathered on the Barí hunters of Venezuela, we assess the validity of this central assumption. We compare our observed distribution of encounter frequencies with an expected Poisson distribution, utilizing chisquare tests and graphic representations. The results are strikingly consonant with the expected Poisson distribution and lend support to the applicability of optimal foraging models to human hunting behavior.     

Isolation and characteristics of Thiopedia rosea (neotype)

Four new strains of Thiopedia rosea were isolated in pure culture from blooms of platelet-forming purple sulfur bacteria in the top layers of the anoxic hypolimnia of two freshwater lakes. Individual cells of the new strains as well as of T. rosea strain 4211 were spherical to oval, nonmotile and contained gas vesicles in the central part. The predominant photosynthetic pigments were bacteriochlorophyll a and okenone. All strains were strictly anaerobic and obligately phototrophic. Optimal growth occurred at low light intensities of 100 E · m^-2 s^-1 (tungsten lamp); intensities above 150 E · m^-2 s^-1 inhibited growth completely. Photoautotrophic growth was possible at sulfide concentrations up to 0.6 mM; higher concentrations were inhibitory. Acetate, butyrate and valerate supported photoorganotrophic growth in the presence of bicarbonate and sulfide concentrations below 1 mM. Sulfide was required as a source of cellular sulfur because assimilatory sulfate reduction is lacking. All strains were assigned to the species Thiopedia rosea with strain 4211 as a neotype.Dedicated to Prof. Dr. H. G. Schlegel on the occasion of his 66th birthday     

Linkage data suggesting allelic heterogeneity for paramyotonia congenita and hyperkalemic periodic paralysis on chromosome 17

Summary Paramyotonia congenita (PC), an autosomal dominant non-progressive muscle disorder, is characterised by cold-induced stiffness followed by muscle weakness. The weakness is caused by a dysfunction of the sodium channel in muscle fibre. Parts of the gene coding for the -subunit of the sodium channel of the adult human skeletal muscle (SCN4A) have been localised on chromosome 17. To investigate the role of this gene in the etiology of PC, a linkage analysis in 17 well-defined families was carried out. The results (z=20.61, =0.001) show that the mutant gene responsible for the disorder is indeed tightly linked to the SCN4A gene. The mutation causing hyperkalemic periodic paralysis (HyperPP) with myotonia has previously been mapped to this gene locus by the same candidate gene approach. Thus, our data suggest that PC and HyperPP are caused by allelic mutations at a single locus on chromosome 17.Dedicated to Professor P. E. Becker on the occasion of his 83rd birthday.