Biomedical subjects
Publications and source records attributed to A B Harris.
A case of lipomatous (lipoblastic) meningioma is described. Atypical radiographic features of low density on computed tomography scanning and high intensity on T1-weighted magnetic resonance imaging corresponded to the presence of adipose tissue within the tumor. A review of the literature indicates few similar reported cases.
Immunocytochemical localization of glutamic acid decarboxylase (GAD), the synthesizing enzyme for the neurotransmitter gamma-aminobutyric acid (GABA), has been used to study the time course of the decrease in putative GABAergic synaptic terminals that occurs in an alumina gel-induced model of focal epilepsy. Monkeys were studied at progressive intervals following unilateral application of alumina gel to sensorimotor cerebral cortex, and were categorized into 3 different experimental groups depending upon their clinical status. These groups respectively exhibited: (1) no abnormal bioelectrical (EEG and ECoG) activity; (2) abnormal bioelectrical activity, but no clinical seizures; and (3) both abnormal bioelectrical activity and clinical seizures. Normal and sham-operated monkeys were also studied. The amounts of GAD-positive terminal-like structures were determined on control and experimental sides of motor cortex (layer V) of all specimens with an image analysis system. This quantitative study revealed that monkeys from the 3 experimental groups showed reductions of GAD-positive terminals on the experimental cortical side, with greater losses occurring at progressively longer times following alumina gel implants. Statistical tests showed that there were no significant cortical side differences for the normal and sham groups, but that cortical side variations were significantly different for each of the 3 experimental groups. Conventional electron microscopy of an early experimental stage revealed degenerating axon terminals in layer V of motor cortex, as well as phagocytosis of degenerating material and astrogliosis. Similar findings were obtained from a chronically epileptic specimen, except that degenerating terminals were observed less often and fibrous astrocytic scarring was more prevalent, especially surrounding the somata of pyramidal neurons. The main conclusion drawn from the results of this investigation is that significant decreases of GAD-positive terminals occur prior to the onset of clinical seizures, and this is consistent with a causal role for a loss of GABAergic innervation in the development of seizure activity in this primate model of focal epilepsy.
A toxicologic-pathologic study of isobutyl-2-cyanoacrylate (Bucrylate) was carried out first in dogs and then in humans whose arteriovenous malformations were infused with this embolic agent. The canine specimens obtained at 7, 18, 28, and 147 days after embolization showed the development of a mild histiocytic giant cell reaction, which evolved to end-state sclerotic arteritis. The response was confined to the vessels and did not involve contiguous parenchymal tissues. Ten human specimens, obtained from 1 hr to 7 years after treatment, showed a similar bland reaction with no evidence of suppuration or premalignant changes.
We evaluated the superoxol (catalase) test as a means of differentiating gonococci from related species of organisms which were cultured from a variety of anatomical sites. An isolate was almost certainly not a gonococcus if it gave a negative superoxol test result, as all but one of 596 available gonococci gave positive test results. However, a proportion of the non-gonococcal neisseriae and isolates of Branhamella catarrhalis, also gave positive test results. The superoxol test is thus a useful addition to the techniques available for the characterisation of gonococci, but additional procedures are needed to confirm the identities of isolates giving positive results.
Among patients attending a clinic for sexually transmitted diseases, women without gonorrhoea were significantly less likely to be colonised with meningococci than were women with gonorrhoea, men with gonorrhoea and men without gonorrhoea: the respective carriage rates (per cent) for groupable plus non-groupable meningococci were 16, 26, 23 and 31. Considering groupable and non-groupable meningococci separately it was found that women without gonorrhoea were also significantly less likely to be colonised with groupable meningococci but there were no significant differences in the carriage rates of non-groupable meningococci. The association between ano-genital gonorrhoea and meningococcal colonisation of the pharynx observed previously with certain groups of patients most likely results from increased mouth-to-mouth contact in 'high-risk' patients rather than individual susceptibility to neisserial infection. The possibility that there is a difference in the predominant means of spread of groupable and non-groupable meningococci is discussed.
Genetic transformation, an indirect sandwich enzyme-linked immunosorbent assay (ELISA) and the Limulus amoebocyte assay were used to indicate the presence of products of Neisseria gonorrhoeae in vaginal and uterine cervical aspirates from 37 women attending a Department of Genito-Urinary Medicine. In parallel with these tests, qualitative and quantitative assessments of the microbial content of aspirates were made. There was wide variation in the numbers of gonococci cultured. The mean viable count for cervical aspirates was 1 x 10(6) cfu/ml and the range was (5 x 10(3))-(8 x 10(6)) cfu/ml; the mean count for vaginal aspirates was 8.4 x 10(4) cfu/ml and the range (1 x 10(2))-(1 x 10(6)) cfu/ml. Viable counts of organisms other than gonococci in vaginal aspirates were two to tenfold greater than the corresponding counts for cervical aspirates. Of 20 patients with gonorrhoea confirmed by conventional diagnostic cultures, aspirates from 15 (75%) gave a positive transformation result, and 12 (60%) a positive ELISA result; 16 (84.2%) out of 19 of these aspirates tested by the Limulus lysate assay were positive at a dilution of 1 in 100.
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Epileptic and normal Macaca mulatta monkey cortex was investigated using ligand binding techniques. Subpial injections of aluminum hydroxide gel into the left sensorimotor cortex produced stable seizure frequencies over a two year period and resulted in specific biochemical and receptor abnormalities. Pair matched CSF samples comparing epileptic and non-epileptic hemispheres showed a significant decreased GABA concentration over the epileptic side. The epileptic cortex demonstrated markedly reduced GABA receptor binding and diminished tissue GABA concentration and GAD activity. Two patterns of receptor loss were observed: nonspecific local cellular drop out involving multiple neurotransmitter receptors; and distal receptor loss which was specific for the neurotransmitter intervention pattern of the cortex. GABAergic receptor loss was more marked than receptor losses for the other neurotransmitter and was more widespread. Scatchard plot analysis demonstrated that the diminished GABAergic receptors within the focus were due to receptor loss and not affinity changes. Spearman rank correlations showed a significant correlation only between the degree of GABAergic receptor loss or decrease in GAD activity and the seizure frequency. Epilepsy appears to be a multifactoral disorder with multiple neuroreceptor abnormalities, the most notable of which are the destruction of GABAergic neurons and GABA receptors.
The membrane-bound enzyme Na+ + K+-ATPase was measured in serially excised specimens of cerebral cortex in epileptic and control monkeys. Experimental chronic epileptic cortex showed significantly lower values than controls, as is seen in some other models and human epilepsy, but is different from the increased enzyme values in cobalt and freezing lesion epilepsy.
Ureaplasma urealyticum was detected in the cervix of 49·9% and in the urine of 47·7% of women attending a department of genitourinary medicine. Isolation of U urealyticum was not related to diagnosis, nor was there any association between the presence of the organism and any symptoms or signs of genital tract disease. Fewer organisms were detected in the cervix of women who had a concurrent infection with Chlamydia trachomatis than in women who had not. A pathological role for U urealyticum has not been established.
Beta-haemolytic streptococci were isolated from throat swabs from 49 (10.5%) of 466 patients undergoing cultural examination for gonorrhoea. Although beta-haemolytic streptococci were isolated more frequently from patients with genital or anorectal gonorrhoea (15.9%) than from those without (9.2%), the difference was not statistically significant. When groupable (A, B, C, or G) and other (non-A, -B, -C, or -G) beta-haemolytic streptococci were analysed separately, as statistically significant association between non-A, -B, -C, or -G streptococci and gonococci was observed but not between groupable beta-haemolytic streptococci and gonococci.
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Using an immunocytochemical method for the localization of the gamma-aminobutyric acid (GABA) synthesizing enzyme, glutamic acid decarboxylase (GAD), we have observed GABAergic nerve terminals distributed throughout all layers of normal monkey sensorimotor cortex. These terminals displayed ultrastructural characteristics that suggested that they arose from aspinous and sparsely spinous stellate neurons. In monkeys (Macaca mulatta and M. fascicularis) made epileptic by cortical application of alumina gel, a highly significant numerical decrease of GAD-positive nerve terminals occurred at sites of seizure foci indicating a functional loss of GABAergic inhibitory synapses. A loss of such inhibition at seizure foci could lead to epileptic activity of cortical pyramidal neurons.
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Specimens from genital, anorectal, and pharyngeal sites from 1671 men and 1419 women were cultured for Neisseria gonorrhoeae. Pharyngeal specimens were also cultured for Neisseria meningitidis, N. gonnorrhoeae was isolated from a genital site 2.7 times more often in men and 1.8 times more in women who also carried meningococci in their pharynx than from those who did not; the meningococcus was isolated 3.4 times more often from men and 2.0 times more often from women with genital gonorrhoea than from those without. In both men and women the association of each organism with the other was statistically significant (p less than 0.001) and may be related to sexual behaviour rather than to individual susceptibility to neisserial infection.
The number of gonoccal infections detected by each of three sets of diagnostic cultures from the urethra, cervix, rectum and occasionally the throat, were calculated for 1976 when Thayer Martin (TM) medium was used and for 1977 when Modified New York City (MNYC) medium was used. In 1977, 98.7 per cent (451/457) of the total infections diagnosed were confirmed by culture compared with 88.3 per cent (324/367) of infections diagnosed in 1976 (P less than 0.001). The first set of diagnostic tests detected 97.6 per cent (440/451) of culture-positive infections in 1977 compared with only 88.9 per cent (228/324) in 1976 (P less than 0.001). The efficiency of screening with a single endocervical culture was also calculated. This procedure would have detected 90.2 per cent (407/451) of culture-positive infections in 1977 when MNYC medium was used compared with only 78.1 per cent (253/324) in 1976 when TM medium was used (P less than 0.001). It is suggested that the statistically significant improvement in the culture results for 1977 resulted from the introduction of MNYC medium since all other diagnostic procedures were identical to those in 1976. Other advantages associated with the use of MNYC medium are discussed.
An infertile patient with amenorrhea-galactorrhea syndrome lost vision during a pregnancy occurring after Bromocryptine treatment. A pituitary adenoma was removed, vision recovered, and the pregnancy completed successfully. Two prior episodes of visual loss had occurred during oral contraceptive treatment, an association not heretofore reported. Intrasellar and parasellar tumors made manifest by hormonal influences of pregnancy may become more common as treatment of infertility becomes more refined and successful.