Hemispheric asymmetry of synapses in chick medial hyperstriatum ventrale following passive avoidance training: a stereological investigation

A stereological analysis was made of synapses in the left and right hemispheres of chick medial hyperstriatum ventrale (MHV) 24h after passive avoidance training (PAL) and in water trained controls (W-control). The synaptic parameters examined were (D), the mean length of the postsynaptic thickening; (NV.syn), the number of synapses per unit volume of neuropil; (VV.syn), the volume density of the pre-synaptic bouton; (NV.ves), the number of synaptic vesicles per unit volume of neuropil and (ves.syn), the mean number of synaptic vesicles per pre-synaptic bouton. No significant differences exist in NV.syn between the left or right hemispheres of W-control and trained chicks, nor is NV.syn influenced by training. However, in W-control chicks D in the right MHV is significantly greater (12%) than in the left MHV and this difference disappears on training. There are no differences in VV.syn between left and right hemispheres of W-control chicks but following training VV.syn is 22.7% greater in the left MHV than in the right MHV. Training als influences the number of synaptic vesicles; in W-control chicks NV.ves in the right MHV is 12.25% greater than in the left MHV but following training these differences are reversed. When the data are expressed as numbers of vesicles per synapse (ves.syn), values for the left hemisphere of trained chicks exceed those in the right hemisphere by a staggering 61.38%. These results are discussed in the context of biochemical and electrophysiological studies which suggest that there is lateralization of the memory trace.

Paired cervical smears: a method of reducing the false-negative rate in population screening

Cervical smears taken by the wooden Ayre spatula (widely used in the United Kingdom) and by a plastic spatula (Armovical) were compared for their ability to detect dysplastic cervical epithelium and endocervical cells. At the same time, the value of taking duplicate smears was assessed. Paired cervical smears were obtained at a single attendance from 21,352 women, using the 2 types of spatulas in 4 different sequences. Although individually the Armovical proved superior to the Ayre spatula for the collection of endocervical epithelial material, this advantage was not complemented by any marked improvement in its detection of cervical dysplasia. Paired smear sampling, however, was clearly more rewarding in this respect and also allowed the introduction of laboratory quality control, as each preparation of any given pair was examined by a different screener. The false-negative rate was 18.5%: it comprised 11.1% sampling error and 7.4% screening error. It is concluded that paired smear sampling in population screening would significantly reduce the false-negative rate.

The value of the electromagnetic flow probe in experimental and clinical microvascular anastomosis

The Gould Statham Blood Flowmeter Model SP 2204 has been used to assess microanastomosis in 25 superficial femoral arteries of rabbits. When a pulsatile wave form has been achieved this correlates with a satisfactory anastomosis and vice versa. The digital read out of estimated volume flow past the anastomosis made by this instrument will need further evaluation. We are persisting with the electromagnetic flow probe in the assessment of our clinical microvascular anastomoses at operation.

The medicalization and legalization of child abuse

Certain symptoms of family crisis and childhood injury are being "medicalized," "legalized," and called "child abuse"--to be processed and dealt with by a range of professionals who derive their social legitimacy and support in the process. Professional conflicts are considered, and the effects of the system on treatment interventions are discussed. Guidelines are offered to minimize the abuse of power of the professional definers.

Platelet monamine oxidase in schizophrenia. An investigation in drug-free chronic hospitalized patients

Platelet monoamine oxidase (MAO) activity was investigated in a series of 60 patients with chronic schizophrenic illnesses free from neuroleptic medication, and 70 normal controls. No significant differences in platelet MAO activity or in substrate preference were detected between patients and controls, using tryptamine and tyramine as substrates. Platelet MAO activity did not distinguish patients with positive symptoms from those with negative symptoms alone and did not show any relationship with severity of disease or with a number of clinical features. These findings suggest that low platelet MAO activity cannot be regarded as a genetic marker for schizophrenia. Important determinants of platelet MAO activity yet to be discovered may have contributed to the discrepancies in recent observations of platelet MAO activity in schizophrenia.

Ureteric vascular and muscle coat innervation in the rat. A quantitative ultrastructural study

The application of a quantitative ultrastructural approach to the study of the innervation of the smooth muscle in the wall of the ureter of the rat has revealed major differences in the structure of the nerves in the muscle coat and in the walls of the arterioles. The high density of adrenergic terminals in the periarteriolar nerves is consistent with the distribution of many of the postganglionic sympathetic axons that run in the ureteric nerves to blood vessels and the low density of both adrenergic and cholinergic terminals in the intramuscular nerves implies that the autonomic nervous system plays only a secondary role in controlling the activity of the muscle. The mean size of the intramuscular nerves corresponds to that of the nerves in the submucosa and terminals of the kind that occur in the submucosal nerves are numerous. The function of axons with such terminals and their possible involvement in the transmission to the central nervous system of pain impulses is discussed.

Trial of new cervical spatula

A trial comparing the relative values of the 'Armovical' and Ayre's spatulae showed a significant improvement of the former over the latter in sampling endocervical epithelium. No such difference was found in their ability to detect epithelial atypia. However, it was confirmed that if (at each attendance of a patient) the cervix was sampled twice instead of once the incidence of atypical smears was increased.

Innervation of the muscle of the bladder in the rat

A quantitative ultrastructural analysis of the organisation and terminal density of the nerves associated with the muscle of the body of the bladder was undertaken in the rat. The results obtained were suggestive of the organisation of the intramuscular plexuses into 2 separate and possibly functionally distinct networks. The nerves ramifying within the muscle fascicles mostly contained between 1 and 3 axons and on the basis of counts made in 12 animals, appeared to provide the muscle with only a moderate level of innervation. Although adrenergic terminals were frequently seen in the perivascular plexuses, they were rarely encountered in the nerves within the muscle fascicles. The majority of the terminals in the intrafascicular nerves were similar to those normally classified as cholinergic and, in many, the exposed parts of the axonal membrane were closely related to that of adjacent muscle cells. In addition to clear vesicles and large dense-cored vesicles, many of these terminals contained scattered small dense-cored vesicles. It was suggested that the involvement of the material present in the small dense-cored vesicles with acetylcholine in impulse transmission might account for the atypical features of such transmission in the bladder and in particular its resistance to blockade by atropine. The nerves forming the interfascicular networks contained few axons with cholinergic terminals, and were characterised by much larger numbers of a morphologically distinctive type of terminal. Some of these were indistinguishable from those recently defined as the terminals of purinergic axons but their distribution in the nerves suggests that they represent the terminals of afferent axons and is consistent with the concept that, together with those observed in other tissues, such axons are involved in pain perception.

Ultrastructure of the submucous nerves of the rat ureter

The fine structure and distribution of the nerves in the submucosa of the middle part of the ureter were studied in the adult rat. As in the rabbit, the nerves were concentrated on the inner surface of the muscle and beneath the epithelium. The nerves beneath the epithelium were smaller than those on the surface of the muscle, but they were much more numerous. They gave off small branches which ran for only short distances in the subepithelial connective tissue before terminating. Axonal varicosities were common and almost all appeared to represent the terminals of a single type of axon. The varicosities contained clusters of clear vesicles and variable numbers of larger dense-cored vesicles. The dense-cored vesicles were unaffected by short-term treatment with 6-OHDA and in this and other respects compared well with those of the terminals classified by Burnstock (1972) as purinergic. The possibility that the axons are sensory, and are the source of impulses which are recognized as being painful in nature, is discussed.