Biomedical subjects
S M Hall
Publications and source records attributed to S M Hall.
Axonal regeneration through heat pretreated muscle autografts. An immunohistochemical and electron microscopic study.
We have compared the regeneration of axons through frozen-thawed or heated muscle autografts in the sciatic nerve of adult rats. Our results have shown that axons regenerate through muscle grafts which had been either frozen-thawed or heated to 60 degrees C prior to transplantation. However, axons failed to regenerate through muscle grafts which had been pre-heated to 80 degrees C. We speculate that this difference may be related to the thermal lability of components of muscle basal lamina, such as laminin and fibronectin, which are known to play an important role in axonal outgrowth.
Infantile axonal neuropathy in two siblings.
Two siblings presented with a recurrent axonal neuropathy associated with intercurrent infection. One child had mild global developmental delay. The CSF was normal and haematological and biochemical tests failed to reveal a metabolic disorder. Nerve conduction studies in both children showed a mixed sensory and motor axonal neuropathy. Sural nerve biopsies showed severe ongoing axonal degeneration. At post mortem examination peripheral nerves showed widespread axonal loss with a marked reduction of anterior horn and posterior root ganglion cells. Mild diffuse endoneurial cell inflammation was present in the peripheral nerves and some posterior roots. We believe that these siblings died from a genetically determined axonal neuropathy with central nervous system involvement.
Cognitive-behavioral intervention increases abstinence rates for depressive-history smokers.
This article describes the test of the hypothesis that a cognitive-behavioral mood management intervention would be effective for smokers with a history of major depressive disorder (MDD). The method was randomized trial; the assessments occurred at Weeks 0, 8, 12, 26, and 52. Ss were 149 smokers; 31% had a history of MDD. All received 2 mg of nicotine gum. Mood management was provided in 10 group sessions over 8 weeks. Standard treatment was provided in 5 group sessions over 8 weeks. Outcome was continuous abstinence. History-positive Ss were more likely to be abstinent when treated with mood management. Treatment condition differences were not significant for history-negative Ss. For history-positive Ss, less anger at baseline predicted abstinence. For history-negative Ss, more years smoked and higher baseline carbon monoxide (CO) predicted abstinence. Cognitive-behavioral therapy did not affect mood after quitting. Abstinence predictors differed as a function of baseline diagnosis.
Central demyelination induced in vivo by the calcium ionophore ionomycin.
The effects of injecting the calcium-selective ionophore, ionomycin, into myelinated tracts in the dorsal columns of adult rat spinal cords were examined electron microscopically. In vivo, ionomycin induced a primary vesicular demyelination, together with a variable degree of axonal degeneration, in a dose-dependent manner. The results are consistent with previous demonstrations that mature oligodendrocytes are more vulnerable to alterations in levels of [Ca2+]i than other glial cells. We speculate that demyelination induced by ionomycin in vivo occurs as a result of direct activation of endogenous Ca(2+)-dependent enzymes and/or as a consequence of oligodendrocyte injury mediated via astrocytes.
Are Schwann cells essential for axonal regeneration into muscle autografts?
When axons regenerate through frozen-thawed (FT) muscle grafts, they are accompanied by co-migrating Schwann cells derived from the nerve stumps. Although acellular, FT muscle grafts contain an internal scaffold of basal laminae rich in components capable of supporting neurite outgrowth in vitro such as laminin and fibronectin: it is not known whether Schwann cells are essential for axonal regrowth within these grafts. In this paper we test the hypothesis that sarcolemmal basal laminae will support axonal regeneration in the absence of Schwann cells. Two groups of 12 adult Wistar rats were used. All rats received a 0.5 cm FT muscle graft, and 12 rats also received a subperineurial injection of the anti-mitotic agent mitomycin C (400 micrograms/ml in physiological saline) prior to grafting. Previous studies have shown that this dose effectively depresses cell proliferation within the endoneurium for 3-4 weeks [17, 18, 28]. Rats were killed (n = 3) 1, 2, 3 or 4 weeks later. The spatio-temporal sequence of axonal regeneration into the grafts was assessed histologically, by immunofluorescence using antibodies against GAP-43; S-100; RT97; laminin and macrophages (ED1), and by transmission electron microscopy. Outgrowth of almost all axons from the mitomycin C-treated proximal stumps was delayed for up to 3 weeks, after which time vigorous regeneration occurred into the persisting tubes of sarcolemmal basal lamina. All axons regenerating within the grafts (irrespective of mitomycin C-treatment) were accompanied by co-migrating Schwann cells. The results suggest that Schwann cells play an important role in axonal regeneration across FT muscle autografts and that sarcolemmal basal laminae alone are insufficient to support axonal regeneration.
Neonatal meningitis in England and Wales: a review of routine national data.
The objective of this study was to describe trends in neonatal meningitis in England and Wales during the years 1975-91. Laboratory reports and, for the years 1983-91, data on statutory notifications and deaths from neonatal meningitis were reviewed. The mean annual total of laboratory reports of neonatal bacterial meningitis 1975-91 was 109 cases (range 69-133) with a slight upward trend apparent in the latter half of the study period. The mean annual number of reports of neonatal viral meningitis was only 14 cases with no trend apparent. The leading bacteria isolated were group B streptococci, Escherichia coli, and Listeria monocytogenes accounting for 34.1%, 28.5%, and 6.8% of reports, respectively. There was a change in the pattern of causative bacteria from 1981 onwards with the group B streptococcus displacing E coli as the leading cause. With respect to neonatal viral meningitis, echoviruses and coxsackie viruses accounted for 55.4% and 38.6% of cases, respectively. Neonatal meningitis was seriously undernotified; the ratio of laboratory reported cases to cases notified ranged from 12:1 in 1985 to 4:1 in 1989. The annual numbers of deaths ranged from 18 to 39. The laboratory reporting system provided the most useful data on secular trends and causative organisms for neonatal meningitis. The slight upward trend in the number of reports of bacterial meningitis merits continued surveillance.
Donor lung preservation: effect of cold preservation fluids on cultured pulmonary endothelial cells.
Pulmonary arterial (PA) endothelial cell morphology changes during cold preservation. In the present study, the efficacy of University of Wisconsin solution (UW), UW solution without colloid (modified UW), Euro-Collins (EC), Marshall's solution (MS), and medium 199 + 10% fetal calf serum [culture medium (CM)] in maintaining and regaining the cytoskeleton of cultured porcine PA endothelial cells kept at 4 degrees C and then rewarmed was compared. Features studied were actin, microtubules, vinculin, and talin, using immunofluorescence, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunoblotting; permeability of the cell sheet; wound healing; and phagocytic capacity. When cooled, microtubules depolymerized in all fluids but EC and MS reduced depolymerization of actin. Permeability decreased at 4 degrees C (P < 0.05), and wound healing and phagocytosis ceased. When rewarmed after EC, UW, and CM preservation, wound healing and phagocytosis started within 15 min and proceeded normally. Permeability returned to normal but was excessive following UW preservation. Microtubule repolymerization was fastest following UW preservation, and actin filament repolymerization was fastest after EC preservation. Thus the type of preservation fluid used influenced the rate of loss and recovery of specific cytoskeletal components, with EC giving the fastest structural and functional recovery.
Correlates of homelessness among substance abuse patients at a VA medical center.
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Treatment research with crack-cocaine-dependent male veterans: the efficacy of different recruitment strategies.
Crack cocaine dependence rapidly leads to physical deterioration and severe social consequences. There is no widely accepted standard of treatment. As such, it is important to attract broad samples of patients into treatment research to improve efficacy and to establish generalizability. Better understanding of what attracts different subgroups of cocaine users into treatment, particularly research-based treatment, is needed. This article assesses the efficacy of six different recruitment strategies for attracting different populations of male veterans into treatment for crack cocaine dependence. New directions are outlined for the examination of recruitment strategies.
Continuity of care and desipramine in primary cocaine abusers.
The objective of this research was to determine the efficacy of enhanced continuity of care and desipramine in increasing treatment attendance and abstinence from cocaine in primary cocaine abusers. Study design was a random assignment, placebo-controlled factorial with assessments at baseline and at 3 (first week of outpatient treatment), 8, and 12 weeks after start of study. Desipramine blood levels were taken at weeks 2 (inpatient), 3, and 8. Subjects (N = 94 men) were recruited on an inpatient ward and assigned to increased continuity of care or to standard treatment, and to active or placebo drug. Main outcome variables were toxicology-verified reports of cocaine use, and attendance at counseling sessions. Enhanced continuity of care increased abstinence from cocaine at week 3 and increased attendance at individual counseling sessions throughout the 12 weeks of the study. There were no main effects for desipramine. Blood levels above 123 ng/ml at week 2 predicted longer stays in outpatient. We conclude that enhanced continuity of care is a low cost intervention that improves early treatment outcome and attendance; desipramine effects do not warrant its therapeutic use.
Listeriosis surveillance: 1992.
The annual reported totals of cases of listeriosis in England, Wales and Northern Ireland have remained low over the last three years and a total of 108 cases was reported in 1992. The clinical and epidemiological features reported in 1992 were similar to those in previous years and in other countries, except for a shift in the seasonal peak to the summer (a pattern consistently seen before the upsurge in 1987) and a reduction in the case fatality rate of non pregnancy-associated cases.
Reye's syndrome in the British Isles: report for 1990/91 and the first decade of surveillance.
The Reye's syndrome (RS) surveillance scheme for the British Isles, jointly organised by the British Paediatric Association and the PHLS Communicable Disease Surveillance Centre, was established in 1981. In the ten years that have followed, there has been a gradual decline in the number, and the age, of cases reported. However, the proportion of cases whose diagnosis was subsequently revised to that of an inherited metabolic disorder, has increased. These trends have been influenced by the change from 'passive' to 'active' case ascertainment in 1986; the aspirin warning issued by the Committee on Safety of Medicines in June 1986; the 1989 influenza epidemic; and the increasing awareness of conditions that mimic RS, particularly inherited metabolic disorders involving defects of fatty acid oxidation. The cases reported in 1990/91 showed the lowest annual incidence recorded so far and a median age of less than ten months (compared with 15 months in the first six years of surveillance). There was a reduction in the case fatality rate in 1990/91 (although still high at 38%) but it is of concern that two children had had pre-admission exposure to aspirin. Parents should be kept aware of the dangers of giving aspirin preparations to children with feverish illnesses.
Alport's syndrome and hereditary motor and sensory neuropathy type I--an unfortunate coincidence.
A 15-year-old boy with Alport's syndrome and hereditary motor and sensory neuropathy type I is described. An association between hereditary motor and sensory neuropathy and a nephropathy has been reported in 12 cases in the literature. Although showing features in common with Alport's syndrome and with a familial tendency, these 12 cases are clinically and histologically distinct from our patient who is the unfortunate inheritor of two genetic disorders, one maternally and one paternally derived. Recognition of an association between nephropathy and neuropathy, although rare, is important.
Observations on the progress of Wallerian degeneration in transected peripheral nerves of C57BL/Wld mice in the presence of recruited macrophages.
The first part of this study is a description of the effect of the intraneural injection of lysophosphatidyl choline into the sciatic nerves of C57BL/Wld mice. This mouse is unusual because its peripheral nerve fibres degenerate very slowly after transection, and few myelomonocytic cells are recruited into the endoneurium after traumatic injury. However, intraneural injection of lysophosphatidyl choline produced a typical demyelinating lesion in which recruited macrophages were active in removal of myelin. In the second part of the study, nerves were transected either before, at the same time as, or some days after, the intraneural injection of lysophosphatidyl choline into the distal stump; the changes within the endoneurium were compared with those seen in distal stumps which had not been injected with lysophosphatidyl choline. Immunohistochemical and ultrastructural examination during the period 1-4 weeks after transection showed that degeneration occurred in the portion of each nerve which had been injected with LPC (and which therefore contained exogenous macrophages) but failed to occur in the portion of nerve which was not penetrated by the injected bolus of lysophosphatidyl choline. It is suggested that the unusual property of sealing off of the tips of the transected axons within the distal stumps may be a significant factor in maintaining 'normal' Schwann cell-axon relationships along transected axons, even though the axons are separated from their cell bodies. Lysophosphatidyl choline destabilises the Schwann cell-axon relationship by initiating myelin breakdown within the Schwann cell. It is suggested that while the Schwann cells remain closely associated with the axons in the distal stumps, they do not behave as denervated cells and consequently may be incapable of signalling their damaged status.
Congenital sensory neuropathy in association with ichthyosis and anterior chamber cleavage syndrome.
Two patients with a congenital neuropathy are described. Both had atypical features including: ichthyosis and a mild anterior chamber cleavage syndrome. Both had severely reduced, or absent, sensation for light touch, vibration, position and temperature. Pain sensation was mildly reduced. There was some evidence of motor involvement but this was relatively minor compared with the sensory involvement. Nerve action potentials were small or absent and sural nerve biopsies showed almost complete absence of myelinated nerve fibres with multiple bundles of abnormally arranged axons and Schwann cell processes. These patients appear to have an undescribed syndrome in which the large sensory neurons and the anterior chamber of the eye did not develop properly. This may reflect a failure of migration, differentiation or proliferation of neural crest cells.
Nicotine, negative affect, and depression.
Depression, whether conceptualized as a trait, symptom, or as a diagnosable disorder, is overrepresented among smokers. Depressed smokers appear to experience more withdrawal symptoms on quitting, are less likely to be successful at quitting, and are more likely to relapse. This article documents these relationships and explores several potential links between smoking and depression. The potential efficacy of antidepressant therapy, cognitive-behavioral therapy, and nicotine replacement therapy for smokers with depressive disorders or traits is discussed. Clinical implications and the role of patient treatment matching are also discussed.