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Biomedical subjects

N Lawrence

Publications and source records attributed to N Lawrence.

52 records · Page 3Linked to original sources
PubMed1989

Neonatal lupus in twins.

Neonatal lupus erythematosus (NLE) is a syndrome characterized by one or all of the following elements: cutaneous LE lesions, systemic disease, and congenital heart block. SS-A/Ro and SS-B/La have been implicated in the etiology of NLE, but because NLE is not uniformly manifested in all offspring of SS-A and SS-B autoantibody positive mothers, and because of the wide range of clinical manifestations associated with NLE, other contributing etiologic factors are being explored. HLA studies have revealed that infants of SS-A/Ro and SS-B/La positive mothers bearing HLA-A1, B8, DR3, DQ2, and DR52 are at greater risk of having NLE. Haplotyping in our dizygous twins supports these material HLA associations.

Antibodies, Antinuclear↗
PubMed1988

Exogenous ochronosis in the United States.

Two middle-aged black women reported hyperpigmentation of the face after using bleaching creams containing hydroquinone. Both noted initial lightening of facial pigmentation followed by progressive darkening of the areas to which the cream was applied. After biopsy, they were found to have exogenous ochronosis. These are the fifth and sixth cases of exogenous ochronosis reported in the United States. In this article we review the literature and discuss the possible pathogenesis of exogenous ochronosis.

Adult↗
PubMed1985

Isolation and differentiation of herpes simplex virus and Trichomonas vaginalis in cell culture.

During the period January 1982 to January 1985, 2,234 specimens were cultured for isolation of herpes simplex virus (HSV). HSV was isolated from 23% of these, Trichomonas vaginalis was isolated from 1.6%, and 75.3% were negative. In 0.2% of these, HSV and T. vaginalis were isolated from the same specimen. Cytopathic effects produced by HSV were identified by their sensitivity to arabinosylthymine, whereas those produced by T. vaginalis were identified by their lack of sensitivity to arabinosylthymine and by observation of motility. Cytopathic effects produced by T. vaginalis were reproduced by trophozoites from axenic cultures of T. vaginalis as well as by lysates of T. vaginalis added to serum-free BHK cells.

Animals↗
PubMed1978

Late endocrine effects of administering monosodium glutamate to neonatal rats.

Rats were injected with monosodium 1-glutamate (MSG) daily for the 1st 5 days of life and allowed to mature. This is known to cause selective destruction of neurons in the retina and in the arcuate nucleus of the hypothalamus. The adult animals had a significant increase in body fat without an increase in weight, a marked reduction in pituitary, thyroid, adrenal, gonadal and prostate weights. Pituitary, hypothalamic and serum thyrotropin (TSH) were significantly reduced in the males. Serum growth hormone (GH) was markedly reduced in both sexes and the serum prolactin (Prl) was increased significantly in females. FSH did not appear to be abnormal and the LH may have been increased in the males. Serum T4 was significantly reduced in females. The fertility of the females was normal, but treated males mated with normal females showed a marked reduction in fertility and, although the litter sizes of the offspring were normal, the birth weights of the pups of both sexes were significantly reduced. These persistent alterations in neuroendocrine function indicate that lesions produced by neonatal MSG treatment provide a convenient model for studying hypothalamic function.

Animals↗
PubMed1976

Inhibition of transplanted sarcomas mediated by BCG in rats with a defined immunological deficit.

Experiments were undertaken to test the hypothesis that a major component of BCG contact-induced inhibition of syngeneic tumour growth in rats is not dependent on the participation of thymus-processed (T) cells. Hosts were deprived of T cells by thymectomy followed by either lethal irradiation (850 rad) and bone marrow reconstitution, or repeated whole body irradiation to a total dose of 1,000 rad. After 6 weeks had elapsed to allow for bone marrow restitution, rats were challenged with trypsinized sarcoma cells admixed with Glaxo strain BCG. For sarcoma P7, host T-cell deprivation did not significantly diminish the capacity of BCG to prevent the progressive development of this neoplasm from an inoculum of one million cells. Under similar conditions, the incidence of sarcoma CC5 development in maximally deprived hosts was significantly greater (7/19) than in normal controls (1/16) (P is less than 0.05), but the majority of rats (58%) did not succomb to tumour outgrowth. In the case of a third neoplasm--a spontaneously metastasizing fibrosarcoma (P8)--the effect of BCG on primary tumour development was comparable in normal and deprived recipients and was limited to temporary arrest as distinct from complete inhibition. Assessment of the influence of BCG on lung metastases was more complex since the extent of metastatic disease from subcutaneous tumour cells alone was greater in deprived rats than in normal rats. It is concluded that T-cell participation is not a major requirement for BCG contact-induced inhibition in this system and some implications for the mechanism of action are discussed.

Animals↗
PubMed1975

Tumour inhibition mediated by BCG in immunosuppressed rats.

Two rat sarcomas (CC5 and P7) which grow progressively on transplantation into normal syngeneic hosts failed to develop when injected in admixture with the Glaxo strain of Bacillus Calmette-Guérin (BCG). Under comparable conditions, the local development of a third neoplasm (P8) was temporarily inhibited and the number of pulmonary metastases significantly reduced. Experiments were undertaken to determine the extent to which the anti-tumor action of BCG required an immunocompetent host. Rats were immunosuppressed by sub-lethal whole-body irradiation (450 R), with or without prior thymectomy and challenged with inocula of mixed BCG and tumour cells when their capacity to respond to bacterial, tumour and unrelated antigens was maximally depressed. In non-sensitized immunosuppressed rats, the ability of BCG to limit tumour outgrowth was abrogated only in the case of sarcoma CC5. For this neoplasm, immunogenic in syngeneic hosts by conventional criteria, there was a statistically significant difference in the number of tumours in immunosuppressed rats (51%) compared with non-sensitized immunocompetent controls (6%). Presensitization to either bacterial or tumour antigens, prior to thymectomy and/or irradiation, fully restored the tumour-inhibitory capacity of BCG. By contrast, sarcoma P7 was not significantly less susceptible to BCG-induced regression in non-sensitized immunosuppressed rats than in nonsensitized normal rats; and sarcoma P8 similarly failed to reveal any significant differences in susceptibility to BCG affecting primary or secondary tumour development. It is concluded that tumours may vary widely in their sensitivity to host reactions aroused by BCG. Certain neoplasms, exemplified by sarcoma CC5, require participation of an immune reaction of delayed hypersensitivity type for optimal destruction at BCG sites, while for others (e.g. sarcoma P7) an immunoreactive component of this type is not essential. By contrast, a third category of tumour (e.g. sarcoma P8) is relatively resistant to host reactions induced by the mycobacteria. An important component of BCG-mediated tumour inhibition is not dependent on an immunologically intact host.

Animals↗