Mycobacterium bovis (BCG) infection of the lymph nodes of normal, immune, and cortisone-treated guinea pigs

Strain-2 inbred guinea pigs were infected intradermally with 10(5)-10(7) viable BCG (Pasteur) organisms by means of multiple scarifications of shaven midflank skin. The spread of the BCG to the draining lymph nodes and on to the spleen was followed quantitatively for 28 days. The population of bacilli at the inoculation site increased as much as tenfold the first 14 days. The number of viable BCG organisms recovered from the primary draining superficial dorsal axillary and inguinal lymph nodes varied from 0.1 to 1.0% of the inoculum, with a further tenfold to 100-fold drop in counts for the secondary subclavian and lumbar lymph nodes. The bacterial counts for the various nodes increased substantially the first 14 days. By 28 days, as many as 1,000 viable bacilli were recovered from the spleen. Increasing the inoculum size or the number of inoculation sites increased the primary node counts and promoted a more extensive and rapid spread by the BCG population to the secondary lymph nodes and spleen. Prior vaccination of the host with living BCG decreased the spread of the BCG inoculum from the scarification site to the various draining lymph nodes. Multiple injections of cortisone tended to reverse this effect.     

Appearance of airway absorption and exudation tracers in guinea pig tracheobronchial lymph nodes

This study examines the fate of extravasated plasma in inflammatory stimulus-challenged large tracheobronchial airways of ketamine-xylazine-anesthetized guinea pigs. Entry of plasma tracers into the airway lumen was determined by a validated noninjurious airway lavage technique. Removal by airway lymphatics was assessed by tracheobronchial lymph node levels of plasma tracers. Mucosal challenges with histamine (5 nmol), bradykinin (5 nmol), capsaicin (0.4 nmol), or allergen (ovalbumin, 3 pmol) increased the appearance of a plasma tracer (131I-labeled albumin previously injected intravenously) in the airway lumen within 10 min (10-20 times control; P < 0.001), whereas the contractile agent carbachol (8 nmol) was without exudative effect. The mediators were without effect, and capsaicin and allergen only slightly increased the lymph node level of plasma exudation tracer (1.5 times control; P < 0.05). Hence, removal via the lymphatic route of plasma macromolecules may be negligible in the acute and postacute phases of an airway exudation response. Experiments were also carried out with luminally applied macromolecular tracers. These were absorbed from the mucosal surface into the circulation, but a small portion was also transported to the lymph nodes, demonstrating the interconnections between the mucosa and the sampled nodes. Only capsaicin produced an increased node level of absorption tracer. Immunohistochemistry showed that the tracheobronchial tissue and lymph nodes are endowed with nerve fibers containing substance P, the release of which may have mediated lymph transport, vascular, and exudative effects of capsaicin in the present studies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Polyamine changes in the vestibular nuclei of guinea pigs following labyrinthectomy

Vestibular compensation is a process of behavioral recovery from ocular, motor and postural disorders following unilateral damage to the vestibular end-organ. Although restoration of the normal resting discharge rate in the ipsilateral vestibular nuclei is important in compensation, the biochemical and molecular mechanisms mediating recovery are largely unknown. The ornithine decarboxylase polyamine pathway is activated in the nervous system following axotomy or denervation. The authors postulate that changes in polyamines mediate vestibular compensation. Within 150-micron brain stem coronal section micropunches analyzed by high performance liquid chromatography techniques, the polyamine spermidine was significantly increased in the ipsilateral lateral vestibular nucleus 8 hours following labyrinthectomy in the guinea pig model. Because naturally occurring polyamines modulate excitatory amino acid receptors (N-methyl-D-aspartate [NMDA]) which in turn mediate neurotransmission between primary afferents and second order vestibular neurons, stimulation of polyamine pathways following neural injury may play a critical role in compensation.     

Pathologic changes during acute Q fever: influence of the route of infection and inoculum size in infected guinea pigs

As assessed by both standard histological staining and immunochemistry, intraperitoneal inoculation of C. burnetii in guinea pigs led to pathologic changes mainly in the liver, whereas intranasal inoculation led to pathologic changes mainly in the lungs. Myocarditis and positive blood cultures were observed only in those animals which received the highest inoculum. We therefore conclude that both the route of infection and the size of the inoculum influence clinical expression in acute Q fever.     

Morphologic and metabolic changes in rat osteoblast cultures during the dark reaction with 8-methoxypsoralen

The dark reaction of 8-methoxypsoralen (8-MOP) with cultured rat osteoblasts did not cause significant changes in cellular replication rates or in the synthesis of RNA and proteins. Microscopic examination, however, revealed that the dark reaction resulted in massive accumulation of perinuclear lipids and in the statistically significant enhancement of alkaline phosphatase activity. A sharp, and statistically significant, upsurge of lipid synthesis in osteoblasts preceded microscopically detectable accumulation of lipids and occurred only during the initial, but not during the subsequent stages of the dark reaction. These results suggest that in the course of the dark reaction the plasma membrane of osteoblasts is a target of psoralen.     

Age-related changes in localization of injected radiolabelled lymphocytes in the lymph nodes of antigen-stimulated mice

The localization of i.v. injected syngeneic lymph node cells, radiolabelled with 51Cr or 75Se-L-selenomethionine, was studied in male CBA/H mice aged between 3 and 30 months. The following results were obtained. (1) Localization of cells from young adult donors was greater in the s.c. lymph nodes of old than of young recipients, the main increase being between 15 and 17 months of age. Increases in lymph node weight and DNA-synthesis were also seen at this time; but the rise in cell localization was significant even when calculated per unit of tissue weight. Splenic localization either declined slightly with age or, like the liver, showed no significant change. (2) Local antigenic stimulation by a single injection of sheep erythrocytes into one front footpad, 24 hr before lymph node cell injection, resulted in increased localization in the regional lymph nodes of 3-17 month old, but rarely of 24-30 month old mice. (3) No consistent differences in localization were observed between lymph node cells from 4-month and 25-month old donors. Both age-related and antigen-related increases in cell localization were at least partly attributable to an enhanced rate of entry of lymphocytes from the blood to the lymph nodes. Although the changes underlying the decline in antigen-related localization of cells in old recipients have still to be clarified, it is probable that the defective immune responses of old mice result partly from this decline.     

Pathology of the lymph nodes in patients with malignant melanoma

The poor survival rate for patients with regional lymph node metastases of malignant melanoma reflects the strong association between lymph node and subsequent visceral metastases. The authors discuss clinical considerations, pathologic risk factors, selective lymphadenectomy, examination of lymph node dissections, difficulties of diagnosis, and prognosis.     

Effects of Ginkgo biloba extract on the cochlear damage induced by local gentamicin installation in guinea pigs

Results from the CMA's 1998 Physician Resource Questionnaire are in, and they point to a serious decline in physician morale. The PRQ, the country's most important poll of physician attitudes, provides an annual "state-of-the-nation" message for the medical profession.     

Morphologic changes of the aortic wall due to reduced systemic pulse pressure in prolonged non pulsatile left heart bypass

The morphologic changes of the aortic wall due to reduced systemic pulse pressure in prolonged non pulsatile left heart bypass (LHB) were investigated. Sixteen adult goats were divided into three groups: the non pulsatile group in which non pulsatile LHB was conducted for 137 days on average, the pulsatile group in which pulsatile LHB was conducted for 79 days on average, and the control group used as the normal control. The average aortic pulse pressures were 12, 48, and 37 mmHg, respectively. At the end of the experiments, the descending aorta was excised and subjected to morphologic examination. The wall thickness of the aorta in the non pulsatile group (1.4 mm) was significantly thinner than that in the pulsatile group (2.2 mm) and the control group (2.0 mm), and the volume ratio of smooth muscle cells (SMC) in the non pulsatile group (37%) was lower than that in the pulsatile group (48%) and the control group (49%). In SMC classification, the proportion of SMC with low activity and low contractility in the non pulsatile group (57%) was high as compared with that in the pulsatile (2%) and control (5%) groups. These results strongly indicate that prolonged non pulsatile LHB causes substantial morphologic changes in the aorta.     

Mast cell activation and migration to lymph nodes during induction of an immune response in mice

The mast cell response in skin and lymph nodes was examined during the sensitization phase of dinitrofluorobenzene (DNFB)-induced contact hypersensitivity in mice. Degranulation of 62% of mast cells in DNFB-exposed skin was evident within 30 min of a dual application of DNFB, reaching a peak of 77% at 24 h, and persisting in 42% after 5 d. Abundant expression of macrophage inflammatory protein (MIP)-1alpha and MIP-1beta mRNAs and proteins was observed in keratinocytes, and mast cell degranulation was significantly inhibited after administration of neutralizing antibodies to MIP-1alpha, but not MIP-1beta. During DNFB sensitization, the mast cell density in the skin decreased by half, concurrent with a fivefold expansion of mast cell numbers in draining lymph nodes. Fluorescent-labeled mast cells injected into the skin appeared in draining lymph nodes after application of DNFB, followed by subsequent migration to the spleen. In lymph nodes, mast cells were an abundant and predominant source of MIP-1beta, neutralization of which partially inhibited T lymphocyte recruitment. These results indicate that mast cells contribute to the induction of this primary immune response by activation at and migration from the site of antigen encounter to draining lymph nodes, wherein they mediate T lymphocyte recruitment by production of MIP-1beta.     

Changes in the distribution of cells expressing tumour-associated antigen in lymph nodes during the progression of enzootic bovine leukosis

A monoclonal antibody (MAb), c143, that recognizes a tumour-associated antigen that is "upregulated" on neoplastic B cells in cattle with enzootic bovine leukosis (EBL), was used as a marker to study disease progression. An immunohistochemical examination of neoplastic tissue and superficial cervical lymph nodes from 14 animals with EBL revealed three morphologically definable stages of change in the structure of lymph nodes, associated with the distribution of c143-positive cells: (1) the presence of c143-positive cells at the marginal sinus with no apparent changes in lymph node structure; (2) the presence of positive cells extending into and distorting the architecture of the lymph node, with clear evidence of proliferation before overt changes (enlargement of lymph nodes) were evident; and (3) the presence of positive cells throughout the lymph node with total disruption of lymph node structure when clinical signs of lymph node enlargement were evident. The results indicated that the bovine leukaemia virus-transformed lymphocytes or neoplastic cells in peripheral blood accumulate in the marginal sinus area at the earliest stages, and subsequently proliferate and infiltrate into follicles, leading to the development of clinical signs of lymphosarcoma.     

Delayed hypersensitivity in the chronic cholera vibrio carrier state in animals with an absence of normal microflora

The development of allergy in germ-free rats in chronic vibriocarriership was studied. The formation of specific delayed type hypersensitivity was found to occur to a limited extent in the animals devoid of normal microflora. The picture of hyperergic inflammation was revealed in the lymph nodes of vibriocarrier rats, the test for specific allergen being positive.     

The social environment during pregnancy and lactation affects the female offsprings'' endocrine status and behaviour in guinea pigs

PURPOSE: To determine the foreign-body response to three intraocular lens (IOL) biomaterials (poly[methyl methacrylate] [PMMA], silicone, and AcrySof) and use this as an indicator of their comparative biocompatibility postoperatively within the eye. SETTING: A British teaching hospital eye department. METHODS: Ninety eyes were prospectively randomized to receive a PMMA, silicone, or AcrySof IOL. All lenses had 6.0 mm optics with PMMA haptics. A standardized surgical protocol was performed by a single surgeon using an extracapsular technique with capsulorhexis; eyes that experienced a surgical complication were excluded. All patients had standardized postoperative medication and follow-up. Specular microscopy of the anterior IOL surface was carried out after pupil dilation on days 1, 7, 30, 90, 180, 360, and 720 to assess small cell and giant cell reactions. RESULTS: All three IOL types produced a mild degree of nonspecific foreign-body response, which resolved over the study period without detrimental effect. The silicone group had significantly higher small cell counts than the PMMA and AcrySof groups (P = .02); the AcrySof group had significantly lower giant cell counts than the other two groups (P = .003). CONCLUSION: The three IOL types were sufficiently biocompatible to function in normal eyes with age-related cataracts. However, AcrySof IOLs were associated with lower giant cell counts than PMMA and silicone IOLs and might produce better results in eyes with pre-existing blood-aqueous barrier damage.     

Power Doppler sonography of cervical lymph nodes in patients with head and neck cancer

We investigated an increase in cases of multidrug-resistant tuberculosis (MDRTB) at a large urban facility where a prior nosocomial outbreak of MDRTB had occurred. Nosocomial transmission appeared to account for this outbreak as well, including a cluster of cases in a newborn nursery. Seven of 24 patients (29%) described in this investigation may have been exposed in the hospital nursery during an approximately 2-week period. We believe this to be the first documented outbreak of MDRTB in a hospital nursery. The transmission in the nursery demonstrates that the possibility of exposure to unrecognized active tuberculosis in nursery and hospital personnel is always present. Infection and active disease in the infants developed after a relatively short period of exposure. These findings underscore the need for adherence to published infection control guidelines in health care settings.     

MR imaging in squamous cell carcinoma of the head and neck with no palpable lymph nodes

PURPOSE: To assess the efficacy of MR imaging in the detection of lymph node metastasis in patients with no palpable lymph nodes ("N0 neck") who have squamous cell carcinoma of the head and neck region. MATERIAL AND METHODS: MR neck imagings in 18 patients who underwent neck dissection (bilaterally in 2) for squamous cell carcinoma of the head and neck region were examined preoperatively for the purpose of detecting lymph node metastases. The imaging features taken into consideration were: size (cutoff point 10 mm), grouping, presence of central necrosis, and appearance of extracapsular spread. The MR examinations comprised spin-echo T1- and T2-weighted sequences. The MR findings were compared with those of surgery and histopathological examination. RESULTS: MR suggested metastatic lymph node involvement in 5 necks. In 2 of these, central necrosis was seen in the enlarged lymph nodes. In a third, a grouping of the lymph nodes was noted. Extracapsular spread was not present. Histopathological examination revealed metastatic lymph nodes in 7 of the 20 necks, the rate of clinically occult disease being 35%, and 4 of them had been accurately graded by MR. There was one false-positive MR examination. The MR sensitivity was 57.1% and specificity 92.3%. CONCLUSION: MR may reveal metastatic lymph nodes in patients with no clinical evidence of metastasis. However, conventional MR techniques are not always sufficient for decision-making on surgery in cases of "N0 neck".     

Anisotropic neural interaction in the primary auditory cortex of guinea pigs with sound stimulation

Neural interaction in the primary auditory cortex of guinea pigs anesthetized with sodium pentobarbital was studied using a single line multi-electrode (4 x 1) aligned across and along the isofrequency band. Under the spontaneous condition, the neural interaction was isotropic; the amplitude of cross-correlogram peaks decreased as the electrode separation increased both across and along the isofrequency band. Under tone stimulation, the neural interaction was anisotropic; the amplitude of peaks was decreased rapidly beyond 400 microm across the isofrequency band, while it decreased little up to 700 microm along the isofrequency band. This anisotropic interaction was dependent on the stimulus intensity.     

An analysis of lymphocyte subsets in the regional lymph nodes of patients with papillary thyroid carcinoma

Lymphocyte subsets in the lymph nodes regional to papillary thyroid carcinoma were determined using flow cytometry to ascertain the differences in local immunological responses between elderly and young patients. Lymph nodes from age-matched patients with benign thyroid tumors were used as controls. No significant alterations in lymphocyte subsets were observed in the lymph nodes from the young patients regardless of whether metastasis was present, whereas those from the elderly patients showed significant decreases in pan T cell (CD2+, CD3+) and cytotoxic T cell (CD8+, CD8+CD11b-) populations, and a significant increase in B cells (CD19+) compared with those from both the young patients and the age-matched controls. These results indicate that local immunological alterations occur in elderly patients with papillary thyroid carcinoma, and we believe that immunological changes are one of the clinical characteristics of this tumor.