Sarcomatoid renal cell carcinoma of papillary origin. A case report and cytogenic evaluation

Sarcomatoid renal cell carcinoma (SRCC) is an aggressive tumor variant thought to arise predominantly from dedifferentiation of clear cell carcinoma. A few reports of SRCC associated with non-clear cell tumors led to the presumption that SRCC may arise from any renal cell carcinoma, although direct evidence of this is lacking. Cytogenetic studies on 3 previously documented SRCCs associated with papillary renal cancers showed either 3p deletions or absence of trisomy 7, 17 in the sarcomatoid tumors, suggesting origin from a coexistent clear cell tumor. The present case represents the first conclusive evidence of direct progression of non-clear cell carcinoma to SRCC with both tumor components containing multiple copies of chromosomes 7 and 17. Many genetic anomalies, including p53 mutations, frequently recognized in SRCC were not recognized in this case, highlighting the importance of cytogenetic evaluation of all SRCC. The patient is well and without evidence of tumor progression 1 year after surgery, and the sinister outlook of SRCC in association with clear cell carcinoma may not apply in SRCC of non-clear cell origin.

Distinction between intraductal carcinoma of the prostate (IDC-P), high-grade dysplasia (PIN), and invasive prostatic adenocarcinoma, using molecular markers of cancer progression

BACKGROUND

Prostate ducts and acini whose lumens are filled with malignant cells represent a well-recognized histological pattern recently termed intraductal carcinoma of the prostate (IDC-P). These tumors are often associated with rapid disease progression, and most recur after radical surgery. Controversy exists as to whether IDC-P should be recognized as a separate entity, an extension of high-grade dysplasia (PIN) or invasive carcinoma as described by the Gleason grading system. This study investigates the use of molecular markers in defining the position of IDC-P in the evolutionary hierarchy of prostate cancer progression.

METHODS

IDC-P, high-grade dysplasia, and invasive cancers from a cohort of 20 selected radical prostatectomy specimens were screened for loss of heterozygosity (LOH), using 12 polymorphic microsatellite markers frequently lost in prostate cancer.

RESULTS

LOH was absent in Gleason grade 3 cancer, infrequent in high-grade dysplasia (9%) and Gleason grade 4 cancer (29%), but common in IDC-P (60%). In IDC-P, and to a lesser extent Gleason grade 4 cancers, multiple sites of allelic loss in individual cases were usual.

CONCLUSIONS

Allelic instability provides further evidence that IDC-P is not a simple extension of dysplasia, nor does it represent invasion of Gleason grade 3 cancers into the ductal/acinar system. IDC-P and Gleason grade 4 cancer represent late but possibly separate events in prostate cancer evolution.

Identification of the glycosaminoglycan keratan sulfate in the prostatic secretory cell

BACKGROUND

Prostate secretory granules (PSG) represent the basic secretory unit of the prostate gland, containing many of its exocrine proteases. Recent analysis of intraluminal corpora amylacea, a proposed by-product of PSG secretion, detected sulfated glycosaminoglycans (GAG) possibly keratan sulfate (KS), indicating a secretory mechanism for GAG in the human prostate surface epithelial cell.

METHODS

Immunostains using anti-KS and anti-prostate-specific antigen (PSA) were evaluated on 10 sequential radical prostatectomy specimens, three of which had received neoadjuvant antiandrogen therapy. Extracts of normal secretory tissue as well as a sample composed almost entirely of prostatic stroma were subjected to Western blot analysis, using the same antibody panel.

RESULTS

Keratan sulfate secretion from the normal prostate epithelial cell has been confirmed and correlates, as does PSA, with the presence of cytoplasmic PSG. No such correlation exists in most adenocarcinomas or in benign epithelium after androgen ablation. Western blot analyses confirmed tissue immunostains and demonstrated a secretory proteoglycan of 70-95 kDa.

CONCLUSIONS

Recognition of PSG heralds a novel secretory mechanism within the human prostate gland that is linked to the secretion of KS. The role of KS in normal prostate secretion remains unknown, although it appears downregulated in neoplastic and androgen-ablated cells.

Variant chromophobe renal cell carcinoma

Separation of renal cell tumors into different prognostic groups is an imperative function of the diagnostic pathologist. Recently, chromophobe renal carcinoma has been described as a tumor that is morphologically distinct from conventional "clear cell" carcinoma and that has a low metastatic potential. Identification is based on routine light microscopic features and is confirmed by special stains, immunohistochemistry, and electron microscopy. We present a variant of chromophobe renal carcinoma that did not show the typical cytomorphologic features on light microscopy after formaldehyde fixation. After fixation in Solufix (a commercial fixative), these features were recognized and the diagnosis was confirmed. The tumor also showed an unusual form of calcification and psammoma body formation not previously recognized in chromophobe tumors. Molecular biological assessment was inconclusive, but excluded a chromosome 3p deletion usually found in conventional renal carcinoma. The use of a different primary fixative may provide a cost-effective screening tool to detect variant renal tumors and may have important prognostic implications.

Luminal contents of benign and malignant prostatic glands: correspondence to altered secretory mechanisms

Recent changes in tissue fixation strategy, using glutaraldehyde, have clarified the secretory mechanisms of the normal prostate identifying cytoplasmic prostatic secretory granules, structures not preserved by formalin fixation. This normal secretory mechanism was absent in most adenocarcinomas, depicting an important metabolic change in transformed prostate cells. The current study further investigates differences between benign and malignant prostate secretion and relates them to the production of corpora amylacea by benign glands and crystalloids or mucin by cancer. In all normal prostate cells examined (6 cases), prostate secretory granules (PSG) were approximately 1-microm, brightly eosinophilic granules filling the cytoplasm of secretory cells and released in packets by a specialized apocrine cell structure. After apocrine decapitation and luminal dispersal, some of the cytoplasmic and PSG remnants condensed to form eosinophilic bodies (EB) with a glycoprotein rim and central protein core. EB were observed adsorbing and layering onto the surface of prostatic corpora amylacea representing their chief mode of enlargement. Biochemical analysis and x-ray diffraction studies confirmed sulfated glycosaminoglycans of similar structure as the main constituent of both PSG and corpora amylacea. Peripheral zone amphiphilic "dark cell" carcinoma (9 cases) contained almost no PSG, and showed neither apical decapitation nor EB formation, but mucin secretion was frequently detected. Crystalloids that share the same staining characteristics and sulfur content as PSG and corpora amylacea were identified in 3 selected "clear cell" carcinomas, all of which showed at least focal PSG secretion. The recognition of these differing secretory mechanisms and their deviation from normal further defines the histological criteria and spectrum of prostate malignancy.

Lymphoepithelioma-like carcinoma of the renal pelvis

We report the first documented case of undifferentiated carcinoma of the renal pelvis with a prominent lymphoid stroma (lymphoepithelioma-like carcinoma [LELC]). LELCs are morphologically identical to nasopharyngeal carcinoma and are rarely seen in the urinary tract, with only isolated cases involving the urinary bladder and ureter. The tumor was composed entirely of large pale staining malignant epithelial cells with ill-defined borders arranged in syncytial sheets separated by mainly reactive lymphocytes, occasional plasma cells and histiocytes. Tumor cells were immunoreactive to cytokeratin and were negative for leukocyte common antigen. Awareness of LELC is important, as it should be distinguished from lymphoma or inflammatory lesions including, xanthogranulomatous pyelonephritis.

Murine progesterone receptor expression in proliferating mammary epithelial cells during normal pubertal development and adult estrous cycle. Association with eralpha and erbeta status

The ovarian steroids estrogen and progesterone are important in directing the normal growth and development of the mouse mammary gland. Previously, we have demonstrated that the majority of proliferating mammary epithelial cells do not express estrogen receptor-alpha (ERalpha). In this study we examined the relationship between progesterone receptor (PR) expression and proliferation in mammary epithelial cells using simultaneous immunohistochemistry for progesterone receptor (PR) and tritiated thymidine [(3)H]-Tdr) autoradiography. Results showed that the majority (>80%) of mammary epithelial cells labeled with [(3)H]-Tdr were PR-positive in the terminal end buds (TEBs) of pubertal mice and the ducts of pubertal and adult mice. Whereas the majority of mammary epithelial cells were also PR-positive, the basal cell population, which comprises the minority of mammary epithelial cells in the mammary ducts, was predominantly PR-negative. Nevertheless, the PR-positive phenotype remained the major proliferating cell type in the basal population. These findings suggest that the progesterone signaling pathway is involved in the proliferation of basal cell populations, potentially directing formation of tertiary side branching during pubertal development and alveolar bud formation in adult glands. A proportion of the basal cells exhibited weak expression of ERbeta, suggesting that the role of ERbeta in mediating normal estrogen-induced responses should be further studied. (J Histochem Cytochem: 47:1323-1330, 1999)

Murine progesterone receptor expression in proliferating mammary epithelial cells during normal pubertal development and adult estrous cycle. Association with eralpha and erbeta status

The ovarian steroids estrogen and progesterone are important in directing the normal growth and development of the mouse mammary gland. Previously, we have demonstrated that the majority of proliferating mammary epithelial cells do not express estrogen receptor-alpha (ERalpha). In this study we examined the relationship between progesterone receptor (PR) expression and proliferation in mammary epithelial cells using simultaneous immunohistochemistry for progesterone receptor (PR) and tritiated thymidine [(3)H]-Tdr) autoradiography. Results showed that the majority (>80%) of mammary epithelial cells labeled with [(3)H]-Tdr were PR-positive in the terminal end buds (TEBs) of pubertal mice and the ducts of pubertal and adult mice. Whereas the majority of mammary epithelial cells were also PR-positive, the basal cell population, which comprises the minority of mammary epithelial cells in the mammary ducts, was predominantly PR-negative. Nevertheless, the PR-positive phenotype remained the major proliferating cell type in the basal population. These findings suggest that the progesterone signaling pathway is involved in the proliferation of basal cell populations, potentially directing formation of tertiary side branching during pubertal development and alveolar bud formation in adult glands. A proportion of the basal cells exhibited weak expression of ERbeta, suggesting that the role of ERbeta in mediating normal estrogen-induced responses should be further studied. (J Histochem Cytochem: 47:1323-1330, 1999)

Androgen receptor expression of proliferating basal and luminal cells in adult murine ventral prostate

Maintenance of the size and differentiated function of the adult prostate is dependent on testicular androgens. In this study, simultaneous androgen receptor (AR) immunohistochemistry and [(3)H]thymidine labelling was used to characterise the proliferating epithelial cells of the murine ventral prostate. Proliferation in the adult prostate was more prevalent in the basal cell population with 1.8&percent; AR-negative cells labelled with [(3)H]thymidine as compared with 0.7% AR-expressing luminal cells. Three weeks following castration of mice, the atrophied prostate contained rudimentary glands composed of both luminal and basal cells with the proportion of AR-expressing basal cells reduced from 50 to 25%. Administration of testosterone enanthate to castrated mice induced a recapitulation of the prostate gland that was preceded by up-regulation of AR expression in basal cells to normal adult levels (50% AR-positive cells) by 12 h following testosterone injection. Proliferation of AR-positive luminal cells peaked at 48 h (22.8%) while proliferation of AR-negative basal cells peaked at 96 h (6.1%) following testosterone administration. These results suggest that distinct populations of luminal and basal cells are resistant to castration-induced involution of the prostate but remain responsive to direct or indirect testosterone effects and recapitulate the gland following administration of testosterone.

Characterization of cytoplasmic secretory granules (PSG), in prostatic epithelium and their transformation-induced loss in dysplasia and adenocarcinoma

Cytoplasmic clarity is a histological feature of normal prostatic secretory cells, but in this study, tissue fixation in strong (>2.5%) glutaraldehyde dramatically altered cytological staining. Secretory cytoplasm appeared red and granular on routine stains because of myriad intensely staining eosinophilic granules (PSG). Immunostaining for prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) showed their exclusive localization to the PSG. Electron microscopy confirmed these findings and also showed that after fixation in many agents, including formaldehyde, PSG appeared empty, accounting for the artefactual "clear cell" appearance on light microscopy. PSG were most densely concentrated apically in a bud-shaped luminal compartment in which cytokeratin was selectively absent. Normal exocrine secretion was visualized as detachment of apocrine buds or their in situ disintegration. Distinctively in dysplasia and almost all carcinomas, PSG were rare to absent, and proteases were free in the cytoplasm, often concentrated beneath the apical membrane. The apocrine compartment was absent, with no observed secretory mechanism. Tumor cells had dark amphiphilic cytoplasm after all fixatives. This provided a reliable method of distinguishing malignant from benign glands in tissues fixed in strong glutaraldehyde. Clear cell carcinomas, whose cytoplasm mimicked routinely fixed normal secretory cells, surprisingly had almost no PSG. Instead, their "granules" were lipid-filled vacuoles reflecting a secretory pathway not seen in normal cells, dysplasia, or the common "dark cell" carcinomas. These observations may define two distinctive biological pathways of prostate cancer evolution and may facilitate diagnostic decisions on needle biopsy samples.

Protein kinase CK2 activities in human prostatic and seminal-vesicle secretions and seminal plasma

Human prostatic secretion and seminal plasma contain certain protein kinase activities. Protein kinases play important roles in regulating a vast variety of cellular functions. The objective of this study was to determine whether one of these protein kinase activities in human prostatic secretion and seminal plasma is due to CK2, a messenger-independent, serine/threonine protein kinase that has considerable potential as a regulatory enzyme. By employing an anti-CK2 antibody and a CK2-specific peptide substrate, we have established that CK2 is present in these secretions. Approximately 70% of the CK2 activity present in seminal plasma of normozoospermic men (n = 49) is correlated to the number of sperm originally present in the semen. Further, both the prostate gland and the seminal vesicles are sources of CK2 activity in the seminal plasma of vasectomized men (n = 38). Although there was considerable variation between individuals in CK2 activity, the variation in repeat semen samples of the same vasectomized men (n = 6) was within 21%. There was no correlation of CK2 activity in seminal plasma with age for vasectomized (27-48 years, n = 38), oligozoospermic (28-43 years, n = 24), or normozoospermic men (26-48 years, n = 49). These data suggest that the majority of CK2 activity in the seminal plasma of normozoospermic men originates from sperm but that the prostate and seminal vesicles are accessory sex-gland sources of this enzyme.

Prostate specific origin of dipeptidylpeptidase IV (CD-26) in human seminal plasma

PURPOSE

A number of peptidases which can metabolize certain bioactive peptides and growth factors have been identified in seminal plasma. Our goal in this study was to determine molecular properties and the tissue source(s) for one of these peptidases, dipeptidylpeptidase IV (DPP IV), in human seminal plasma.

MATERIALS AND METHODS

We measured the activities of DPP IV with the dipeptide glycylprolyl-p-nitroanalide and its molecular forms using immunoblotting of seminal plasmas of men who were vasectomized or with different sperm concentrations, and in prostatic and seminal vesicle secretions of men undergoing prostatic surgery.

RESULTS

DPP IV in seminal plasma of vasectomized men was a membrane associated dimer comprised of subunits of approximately 110 kDa. Its activity did not differ in seminal plasmas of vasectomized, azoospermic, oligozoospermic and normozoospermic men indicating no correlation with the concentration of sperm originally present in the semen. The DPP IV antigen (CD -26) and enzymic activity were present in prostatic secretion, but absent from that of the seminal vesicles. These data indicate that the prostate gland is the primary source of DPP IV activity in seminal plasma. There was little variation in its activities in repeat seminal plasma samples from the same individual, and there was no change in its activity with age to 50 years.

CONCLUSIONS

DPP IV in seminal plasma was derived from the prostate gland and it may be useful as a bioindicator of prostate function and/or disease with age in men.

Development of PCR assays for species- and type-specific identification of Pasteurella multocida isolates

Genomic subtractive hybridization of closely related Pasteurella multocida isolates has generated clones useful in distinguishing hemorrhagic septicemia-causing type B strains from other P. multocida serotypes. Oligonucleotide primers designed during the sequencing of these clones have proved valuable in the development of PCR assays for rapid species- and type-specific detection of P. multocida and of type B:2 in particular. This study demonstrated that the primer pair designed from the sequence of the clone 6b (KTT72 and KTSP61) specifically amplified a DNA fragment from types B:2, B:5, and B:2,5 P. multocida and that the primers KMT1T7 and KMT1SP6 produced an amplification product unique to all P. multocida isolates analyzed. It was also shown that PCR amplification performed directly on bacterial colonies or cultures represents an extremely rapid, sensitive method of P. multocida identification.

Development of PCR assays for species- and type-specific identification of Pasteurella multocida isolates

Genomic subtractive hybridization of closely related Pasteurella multocida isolates has generated clones useful in distinguishing hemorrhagic septicemia-causing type B strains from other P. multocida serotypes. Oligonucleotide primers designed during the sequencing of these clones have proved valuable in the development of PCR assays for rapid species- and type-specific detection of P. multocida and of type B:2 in particular. This study demonstrated that the primer pair designed from the sequence of the clone 6b (KTT72 and KTSP61) specifically amplified a DNA fragment from types B:2, B:5, and B:2,5 P. multocida and that the primers KMT1T7 and KMT1SP6 produced an amplification product unique to all P. multocida isolates analyzed. It was also shown that PCR amplification performed directly on bacterial colonies or cultures represents an extremely rapid, sensitive method of P. multocida identification.

Estrogen receptor-negative epithelial cells in mouse mammary gland development and growth

The mouse mammary gland undergoes rapid proliferation during puberty, then cyclical proliferation and involution during adulthood within a 5-day estrous cycle. Although proliferation of mammary epithelial cells is directed by elevated serum levels of estrogen acting via the estrogen receptor (ER), the ER status of the proliferating cells remains unknown. We examined the ER expression of proliferating epithelial cell types during pubertal development and normal adult growth using simultaneous immunohistochemistry for ER and tritiated thymidine (3H-Tdr) autoradiography. These studies demonstrate that during pubertal growth (4-6 weeks) ER-negative cells comprise more than 50% of the epithelial cell populations in the terminal end buds (TEBs) and ducts. Furthermore, the majority of proliferating cells in both TEBs and ducts are ER-negative. These findings indicate that proliferation of cells within both the TEBs and the mammary ducts contribute to pubertal growth of the mammary gland and that the greater proportion of dividing cells are ER-negative. Similar patterns of cell growth were observed in the normal estrous cycle when the majority of dividing cells were ER-negative during both pro-estrous and estrous. Intensive labelling of cells with 3H-Tdr was used to identify long-lived mammary epithelial cells which retained 3H-Tdr 2 weeks following labelling (i.e., following 3 estrous cycles). Of the small number of mammary epithelial cells retaining 3H-Tdr label, most were ER-positive luminal cells and only a few were ER-negative basal cells. This study indicates that pubertal growth of the mammary gland comprises division of ER-negative cap cells and of both ER-negative and ER-positive cells in the body of the TEBs and elongating mammary ducts. Similarly, estrogen-driven proliferation of ER-negative and ER-positive luminal cells and ER-negative basal cells maintains the differentiated mammary gland in the adult mouse.

Assessment of vascularity in breast carcinoma by computer-assisted video analysis (CAVA) and its association with axillary lymph node status

Case-control methodology was used to evaluate the significance of vascularity in small breast carcinomas with regard to the presence or absence of axillary lymph node metastases. Vascularity was assessed in 32 axillary node positive primary breast tumours (LN+ve) less than 2 cm in size and compared with 56 control axillary node negative primary tumours (LN-ve), which were matched for histological type and grade and tumour size. This study design employed computer-assisted video analysis (CAVA) to assess the total blood vessel perimeter (BVP), total blood vessel area (BVA), and total blood vessel density (BVD) throughout a tissue section that encompassed an entire cross section of the tumour and its immediate periphery. The BVA and BVD in these tumours were not significantly different between LN+ve and LN-ve groups. The LN-ve carcinomas had, on average, a significantly (P<0.05) higher total BVP (3355 microm/mm2) than LN+ve tumours (2771 microm/mm2). 'Hot spot' areas were also independently assessed by two pathologists and the same areas measured by CAVA. A strong correlation (P<0.001) between the two methods of assessment of BVD of the neovascular 'hot spots' was found; however, no association with axillary lymph node metastasis was found using either method of assessment. In conclusion, vascularity assessed by either blood vessel density or blood vessel size in primary invasive breast cancers less than 2 cm in diameter showed no association with axillary lymph node metastasis; in fact a negative association was found with total BVP of whole tumour sections and BVD in 'hot spots' using CAVA. Further, this study has established a computer-assisted method of quantifying vascularity in solid neoplasms and is a positive step towards a standardised approach to this diverse and methodologically variable area.

Detection of p53 gene mutation by rapid PCR-SSCP and its association with poor survival in breast cancer

We examined the association between mutation of the p53 gene and survival in a large cohort of breast cancer patients. Using a rapid, non-isotopic single-strand conformation polymorphism (SSCP) method we screened for mutations in exons 4-10 of the p53 gene in 375 primary breast cancers from patients with a median follow-up of 57 months. Mutations were found in 19% of tumours. Statistically significant associations were found between p53 mutation and histological grade, hormone receptor status, ploidy and S-phase fraction. No association was found between p53 mutation and axillary lymph node involvement, histological type, tumour size, vascular invasion or patient age. In univariate survival analysis, p53 mutation was strongly associated with poor prognosis. This was maintained in the lymph node-negative and hormone receptor-positive patient subgroups. In multivariate analysis, p53 mutation was associated with poor survival independent of lymph node status, estrogen receptor status and S-phase fraction. Our results demonstrate the feasibility of using a rapid and simple polymerase chain reaction-SSCP screening procedure to detect p53 gene mutation in breast cancer for the provision of prognostic information.

Analysis of haemorrhagic septicaemia-causing isolates of Pasteurella multocida by ribotyping and field alternation gel electrophoresis (FAGE)

Ribotyping and field alternation gel electrophoresis (FAGE) were used to examine 19 Pasteurella multocida isolates, and to assess the ability of these techniques to differentiate P. multocida strains that cause haemorrhagic septicaemia (HS). Reproducible patterns were obtained from both methods, with FAGE demonstrating greater discriminatory power than ribotyping. FAGE analysis was particularly useful in distinguishing North American cultures originating from the 1922 Yellowstone National Park Buffalo 'B' strain, demonstrating the ability to detect genetic alterations induced by repeated subculture. A remarkable homogeneity was observed among Asian HS strains following ribotyping and FAGE analysis, with a clear distinction observed between virulent and avirulent HS isolates. This study has illustrated the value of genomic fingerprinting methods in distinguishing strains of similar serotype, and the capability of these methods to produce detailed characterisation of P. multocida isolates.

Urinary continence after radical retropubic prostatectomy. Analysis and synthesis of contributing factors: a unified concept

OBJECTIVE

To assess the effects of three types of apical dissection on urinary continence after radical retropubic prostatectomy and to evaluate possible contributing factors, e.g. preservation of the bladder neck and preprostatic sphincter, age, anastomotic strictures, previous transurethral resection and nerve-sparing surgery.

PATIENTS AND METHODS

Having undergone one of three types of apical dissection, 280 patients were evaluated: in Group 1 (sphincter-damaging) 134 patients underwent the original technique of ligating and transecting the venous complex; in Group 2 (sphincter-repairing), 76 patients had the venous complex with part of striated sphincter incorporated within anastomotic suture(s); and in Group 3 (sphincter-preserving), 70 patients had the venous complex alone ligated using the 'bunching' technique of Myers. The outcome was analysed for the number becoming continent and the time to continence.

RESULTS

Continence was achieved in 93% overall, with 90%, 93% and 99% achieving continence in Groups 1, 2 and 3, respectively. The mean time to continence was 68 days overall, taking 100, 52 and 30 days for the respective groups. Twenty patients (7%) did not achieve full continence; 15 had minor incontinence and five severe, with none of the latter being in Group 3. The group (preservation of external sphincter), age and freedom from development of anastomotic strictures were the most important factors both in regaining continence and decreasing the time to continence.

CONCLUSIONS

Preservation of as much as possible of the normal anatomy of the sphincter mechanisms and their nerve supplies results in an excellent return to continence after radical retropubic prostatectomy.

REP-PCR analysis of Pasteurella multocida isolates that cause haemorrhagic septicaemia

Amplification of multiple P multocida genomic DNA fragments by outwardly-directed primers based on the repetitive extragenic palindromic (REP) consensus sequence, generated complex profiles in a PCR-based fingerprinting method known as REP-PCR. Polymorphisms within REP-PCR profiles were used to characterise 38 isolates of P multocida. The high degree of homogeneity observed among haemorrhagic septicaemia (HS) strains of serotype B and E provided evidence of a disease-associated REP profile that may serve as a novel method for the identification of HS strains regardless of serotype. REP-PCR profiles of other P multocida serotypes were highly variable, illustrating the potential of this technique for the molecular fingerprinting of fowl cholera or atrophic rhinitis isolates. A specific amplified REP fragment was isolated and used to probe membrane-bound digested P multocida genomic DNA. Hybridisation patterns not only distinguished HS-causing isolates from non-HS P multocida, but also demonstrated a degree of relatedness between HS and HS-like strains.

Detection of a population of long-lived cells in mammary epithelium of the mouse

The fate of dividing mouse mammary epithelial cells was followed by use of tritiated thymidine (3H-Tdr) autoradiography. Loss of label consistent with halving kinetics was observed at various times after injection; however, heavily labelled cells were frequently observed at two weeks and later, when none was expected. The grain count over these heavily labelled cells was often comparable with that 1 h after 3H-Tdr injection. Extensive serial sectioning revealed that the heavily labelled cells were often single cells surrounded by many unlabelled cells or that their label was in stark contrast (in excess of 20 reduced silver grains) to the surrounding group of cells whose label was just above background (a maximum of 3 grains). In addition, by injecting mice at different stages of oestrus, we demonstrated that these long-lived cells, although influenced by oestrus, replicated independently of the oestrogen peak. Our data support a model for mouse mammary epithelium that has a single 'stem' cell positioned within a group of its progeny to form a discrete proliferative unit. This model requires many such stem cells within the mammary epithelium and is consistent with similar models proposed for other tissues.

Cloning of a unique sequence specific to isolates of type B:2 Pasteurella multocida

Two Carter type B Pasteurella multocida isolates, Izatnagar 52 and 25, isolated from cases of haemorrhagic septicaemia (HS), were used in a modified subtractive hybridisation technique with the specific aim of cloning unique DNA sequences related to the pathogenesis of HS. Biochemical and protein analyses have shown these isolates to be similar, but reports indicate that they have differences in pathogenicity. The subtracted inserts were screened against genomic DNA from a wide range of P multocida isolates, with two distinct fragments demonstrating specific hybridisation with Carter type B isolates that cause HS. No identity was observed with either Carter type E isolates or non-HS type B strains. The clones were sequenced and a search of the GenBank database revealed significant identity of the clone A3b (296 nt) to P haemolytica lipoprotein, whereas there was no significant identity with 6b (956 nt). Both these fragments had a high level of identity (72.8 to 76.9 per cent) to the H influenzae Rd genome.

Predicting axillary lymph node metastases in breast carcinoma patients

Routine axillary dissection is primarily used as a means of assessing prognosis to establish appropriate treatment plans for patients with primary breast carcinoma. However, axillary dissection offers no therapeutic benefit to node negative patients and patients may incur unnecessary morbidity, including mild to severe impairment of arm motion and lymphedema, as a result. This paper outlines a method of evaluating the probability of harbouring lymph node metastases at the time of initial surgery by assessment of tumour based parameters, in order to provide an objective basis for further selection of patients for treatment or investigation. The novel aspect of this study is the use of Maximum Entropy Estimation (MEE) to construct probabilistic models of the relationship between the risk factors and the outcome. Two hundred and seventeen patients with invasive breast carcinoma were studied. Surgical treatment included axillary clearance in all cases, so that the pathologic status of the nodes was known. Tumour size was found to be significantly correlated (P < 0.001) to the axillary lymph node status in the multivariate anlaysis with age (P = 0.089) and vascular invasion (P = 0.08) marginally correlated. Using the multivariate model constructed, 38 patients were predicted to have risk of nodal metastases lower than 20%, of these only 4 (10%) patients had lymph node metastases. A comparison with the Multivariate Logistic Regression (MLR) was carried out. It was found that the predictive quality of the MEE model was better than that of the MLR model. In view of the small sample size, further verification of this model is required in assessing its practical application to a larger population.

Prognostic significance of p53 over-expression in thin melanomas

Metastasis by thin melanomas is uncommon and unpredictable. In order to assess the prognostic value of p53 expression, p53 immunohistochemical staining was evaluated in 20 thin melanomas with documented metastasis and in 20 control tumours which failed to metastasize. Tumours selected were less than 1 mm thick and were individually matched for tumour thickness, date of excision and patient age and sex. The relative risk of metastasis given p53 overexpression was 1.5 (95% confidence interval 0.4-5.3; p = 0.53). Further quantitative analysis for p53 between the two groups did not demonstrate a significant difference (p = 0.08). These results are consistent with there being no association between p53 overexpression in thin melanomas and risk of metastasis, however, the sample size was small, and the existence of such an association cannot be ruled out with confidence. For the 20 thin melanomas which metastasized, there was no association between the proportion of cells positive for p53 and length of the relapse-free period (correlation coefficient = 0.02, p = 0.94).

p53 gene mutation and expression in naevi and melanomas

Mutations of the p53 tumour suppressor gene are common to many human malignancies. Although increased p53 expression has been observed in cutaneous malignant melanoma, mutations of the p53 gene appear to be infrequent. We examined 140 benign and malignant paraffin-embedded melanocytic lesions for p53 protein expression by immunohistochemistry, using the monoclonal anti-p53 antibody DO-7 and a microwave method of antigen retrieval. Fifteen naevi and 25 melanomas were further analysed for p53 mutations within exons 5-8 of the p53 gene. DNA was extracted from paraffin sections and screening for mutations was carried out using PCR-SSCP. We demonstrated p53 protein expression in 33% of naevi (17 out of 51), 35% of primary melanomas (20 out of 58), and 70% of metastatic lesions (15 out of 21). p53 expression in benign lesions was weaker than in malignant lesions in intensity and percentage of cells staining. p53 protein expression in melanomas increased in intensity and percentage of cells staining with tumour progression. In 25% (three out of 12) of metastatic melanomas p53 mutations were detected by PCR-SSCP and increased expression of p53 protein was observed in these tumours. p53 gene mutations were not detected in any benign melanocytic lesions. We demonstrate that antigen retrieval techniques increase p53 immunoreactivity in paraffin embedded melanocytic tissues. p53 protein expression in melanomas increases with depth of tumour invasion. As p53 gene mutations occur infrequently in malignant melanoma, other mechanisms are proposed to influence p53 protein expression in melanocytic lesions.

Evaluation of the expression levels of nm23-H1 mRNA in primary breast cancer, benign breast disease, axillary lymph nodes and normal breast tissue

Expression levels of nm23-H1 were evaluated in a variety of normal benign and malignant breast tissues by Northern and slot blot. Tissues from 153 patients presenting with palpable breast lesions were studied: 132 primary infiltrating breast cancers, 9 pure duct carcinoma in situ lesions, a phyllodes tumor, 9 benign lesions and 2 local recurrences of carcinoma. In addition to lesional tissue, 49 samples of macroscopically normal breast tissue, 37 axillary lymph nodes and 9 samples from patients undergoing cosmetic reduction mammoplasty were studied. Sets of normal breast tissue, primary tumor and lymph node tissue from individual patients were available for comparison in 37 cases. A wide range of gene expression was detected in the various tissue types. The highest levels of expression were detected in malignant samples with in situ carcinomas being associated with the highest levels of gene expression. The expression levels of nm23-H1 in normal breast tissue were lower than the corresponding tumors from the same patients (p < 0.0005). Benign breast lesions (including 6 fibroadenomas) had levels of gene expression approximating those of the normal tissue samples. Normal axillary lymph nodes had significantly lower levels of nm23-H1 expression than nodes with metastatic deposits (p < 0.03). No significant association was observed between nm23-H1 expression levels and axillary node status in patients with infiltrating carcinoma, although there was a slight trend toward lower nm23-H1 mRNA levels in the node negative group.(ABSTRACT TRUNCATED AT 250 WORDS)

c-erbB-2 amplification in breast cancer: detection in formalin-fixed, paraffin-embedded tissue by in situ hybridization

We describe a sensitive and practical in situ hybridization method, using a digoxigenin-labeled probe, for the detection of c-erbB-2 amplification in breast cancer in formalin-fixed, paraffin-embedded tissue sections. Forty-six primary breast carcinomas were studied. Nuclear hybridization signal was observed in 36 of 46 carcinomas. Signal was confined to malignant cells. Normal breast epithelium and stromal and inflammatory cells were uniformally negative. DNase predigestion, no-probe preparations, and competitive hybridization confirmed the specificity of the reaction. The hybridization reaction was localized to multiple discrete foci in tumor cell nuclei, suggesting multiple sites of gene copy and transcriptional activity in the nucleus. Considerable cell-to-cell variation in hybridization signal was evident within individual tumors and positive reactions were observed in several cases in which amplification could not be detected by either Southern or slot blot analysis. The high sensitivity and specificity of the reaction and its use in a tissue-based system will allow the study of a range of possible precursor lesions of breast cancer for evidence of c-erbB-2 amplification.

What's new in breast cancer? Molecular perspectives of cancer development and the role of the oncogene c-erbB-2 in prognosis and disease

The oncogene c-erbB-2 is frequently amplified in human breast carcinoma. The c-erbB-2 gene is present as a single copy in normal cells, and has been mapped to chromosome 17 in the region 17q 12-21.32. c-erbB-2 encodes a transmembrane glycoprotein known as p185. The intracellular component of p185 has tyrosine kinase activity; the extracellular domain has a structure resembling a growth factor receptor. c-erbB-2 amplification, p185 overexpression and levels of transcribed c-erbB-2 specific messenger RNA have been studied in a large number of breast carcinomas using a variety of techniques. In general, overexpression of p185 oncoprotein reflects various levels of DNA amplification, though in some cases amplification can be detected in the absence of overexpression of p185 and similarly overexpression of p185 can be present without detectable levels of c-erbB-2 amplification. This findings suggests that multiple mechanisms may be responsible for overexpression. c-erbB-2 amplification and/or overexpression occurs in almost all cases of high grade duct carcinoma in-situ, but has been reported in only 10%-40% of infiltrating duct carcinoma. c-erbB-2 amplification or overexpression occurs rarely in invasive lobular carcinoma, and has not been detected in ductal or lobular epithelial hyperplasia, or in atypical ductal or atypical lobular hyperplasia. It is generally believed that c-erbB-2 amplification/overexpression is an important independent prognostic indicator in breast carcinoma, identifying a subset of patients with poor prognosis tumours, particularly if axillary node metasases are present. However, many unanswered questions remain regarding c-erbB-2 and its role in breast cancer development and progression. The causes of c-erbB-2 amplification are unknown. There is no evidence of mutations in the human gene which might cause amplification or overexpression. The significance of the differences in levels of c-erbB-2 amplification/overexpression in in-situ duct carcinoma and associated invasive duct carcinoma has not been established. Amplification or overexpression have not been reported in atypical duct hyperplasia, a proposed precursor of duct carcinoma in-situ, yet overexpression occurs almost always in high grade duct carcinoma in-situ. c-erbB-2 may play a critical role in the development of a clonal in-situ, proliferation of high histological grade, yet does not obviously influence the acquisition of an invasive phenotype. We would postulated that this instability in amplification/overexpression is of biological significance, and if better understood may aid in the study of progression of human breast carcinoma.

Field alternation gel electrophoresis--status quo

Since the description of the original technique of field alternation gel electrophoresis (FAGE) about ten years ago there have been significant developments in the area. Between 1983 and early 1987 dramatic improvements in the technique and apparatus resulted in a 500- to 600-fold increase in the functional separation capacity of conventional agarose gel electrophoresis. Details of the improvements in technique and equipment was the subject of an earlier review [H. J. S. Dawkins, J. Chromatogr., 492 (1989) 615]. This review concentrates on the application of FAGE technology. The FAGE technique is no longer restricted to simply separating large DNA fragments. This method is presently being used for electrophoretic karyotyping, long-range genomic mapping, cloning of large DNA fragments into new vectors, the study of pathogenic chromosomal alterations and the structural analysis of chromosomes. The applications of FAGE in molecular biology and genetics is constantly expanding, with the full potential of this technique still to be realised.

c-erbB-2 amplification and overexpression in breast cancer: evaluation and comparison of Southern blot, slot blot, ELISA and immunohistochemistry

The oncogene c-erbB-2 has been shown to be amplified in 17-30% of breast cancers, with similar levels of overexpression of the oncogene product p185, a transmembrane growth factor receptor glycoprotein. Amplification of c-erbB-2 is now generally considered to be a significant prognostic indicator in patients with breast cancer. A series of 74 consecutive breast carcinomas were analysed for c-erbB-2 amplification and p185 overexpression. The procedures of Southern blotting and slot blot were used for the analysis of oncogene amplification, while immunoperoxidase (IPOX) staining and enzyme-linked immunosorbent assay (ELISA) were used for the analysis of p185 overexpression. Detection of c-erbB-2 oncogene amplification by both the conventional Southern blotting technique and by the slot blot technique showed complete accord, with the amplified c-erbB-2 oncogene being detected in 14 of the 74 patients (18.9%). The c-erbB-2 oncoprotein, as measured by IPOX and ELISA, was found to be overexpressed in 21% and 19% of patients, respectively. Comparison was made between the results attained by all four methods, and further comparison of the techniques was made from the point of view of ease of use, expense and ease of introduction into routine diagnostic laboratories. Immunocytochemistry in combination with slot blotting procedures were considered to be the most cost effective methods for evaluation of overexpression and amplification in routine pathology laboratories.

Electrophoretic profiles of Pasteurella multocida isolates from animals with hemorrhagic septicemia

We determined that the protein profiles of 14 isolates from animals with hemorrhagic septicemia were relatively homogeneous and could be placed in 2 distinct groups on the basis of their country of origin. Such differences correlated with the serotypic properties of the individual isolates; hemorrhagic septicemia isolates of Asian and North American origin (Carter B) had a major protein band with an apparent molecular mass of 32 kDa, whereas those of African origins (Carter E) had a major protein band with an apparent molecular mass of 37 kDa. The possession of a major 32-kDa protein band appeared to be unique to Carter B isolates, suggesting that electrophoresis may be a useful nonserologic technique for the identification of organisms of this serotype. Other major bands with apparent molecular masses of 27, 45, and 47 kDa were shared by all strains, regardless of their serotype. The lipopolysaccharides were of low molecular mass and relatively uniform from 1 isolate to the next.

Pasteurella multocida septicaemia in fallow deer (Dama dama)

Thirteen of 100 fallow deer, aged between 6 months and 10 years, died over a 5 week period. The deaths occurred in 2 outbreaks 3 weeks apart. Both outbreaks were preceded by at least 3 days of cold wet and windy weather, and were associated with water-logged pastures. Affected animals were usually found dead, with a frothy blood-stained nasal discharge. In the 8 deer necropsied, gross lesions included widespread subserosal petechial haemorrhages, severe pulmonary congestion and oedema with froth-filled airways, and fibrinous pneumonia and pleurisy in 4 deer. Two deer, also, had extensive subcutaneous petechial and ecchymotic haemorrhages and oedema of skeletal musculature. Histologically, the most significant lesions were present in the lungs. Moderate to severe pulmonary congestion and oedema, with fibrinous exudation into alveoli and septal oedema, were present in all deer. In some deer these changes were accompanied by a diffuse infiltration with polymorphonuclear leucocytes. Pasteurella multocida was isolated from a range of tissues from 7 of 8 deer examined. The remaining animal had been treated with antibiotics 8 hours before death. The isolates had identical polyacrylamide gel electrophoresis patterns and were of the same antigenic type-Carter group A, Heddleston type 3,4.

Haemorrhagic septicaemia: correlation of vaccinal antibody responses in mice with protection against Pasteurella multocida strain M1404

This study examined the protection induced by oil adjuvant vaccine and broth bacterin in mice. Protective immunity was induced by both oil adjuvant and bacterin vaccination procedures. Oil adjuvant vaccination induced a 10(5)-fold increase for lethal challenge over control mice, while secondary vaccination induced a further 10-fold increase in resistance to lethal challenge. Broth bacterin induced a slightly weaker protective response with 10(4)- and 10(5)-fold increases in resistance to lethal challenge following primary and secondary vaccination, respectively. There was a significant relationship between IgG antibody levels and resistance to challenge (P = 0.026). Protection lasted for at least 20 weeks after a primary oil adjuvant vaccination. There was also a strong and significant relationship between IgG antibody levels and the passive protection afforded by serum transfer in each experiment within this study and the overall correlation was highly significant (P = 0.00001). There appeared to be a relationship between protection and the antibody response to major protein bands with the apparent molecular mass Mr. 94,000; 80,000; 67,000; 35,000 and 32,000 as well as to the bands in the region of the lipopolysaccharide components of P. multocida (approximately Mr, 14-15,000). Whether protection resulted from recognition of specific antigens or was a result of both antibody levels and antibody specificity remains to be defined.

Evidence of phenotypic dichotomy within an individual Pasteurella multocida type strain and among some haemorrhagic septicaemia-causing field isolates

Haemorrhagic septicaemia-causing strains of Pasteurella multocida were identified by a disease-specific ELISA. Some strains, however, were of the same serotype as those which cause haemorrhagic septicaemia (HS) but were negative when tested in the disease specific ELISA. The suspect false negative isolates were passaged in mice and retested in the HS ELISA with the same result. Immunoelectron microscopy was used to examine further these suspect HS-causing strains. Monoclonal antibodies and protein A-gold showed that the suspect negative organisms were a mixture of phenotypes with less than 10 per cent, and usually less than 2 per cent, of the population expressing HS-associated epitopes. The degree of staining on the organisms expressing the HS-epitopes was of the same intensity as the positive control organism. Expression of the HS-associated epitopes is presumably too low to allow detection in the current HS ELISA.

Rapid identification of Pasteurella multocida organisms responsible for haemorrhagic septicaemia using an enzyme-linked immunosorbent assay

Haemorrhagic septicaemia (HS) is caused by specific serotypes of Pasteurella multocida and is one of the major economic diseases of cattle and buffalo in South East Asia. Definitive diagnosis of the disease-causing organism with the available methods is labour intensive and not totally reliable, consequently, an ELISA system to identify P multocida organisms which cause HS was developed. One hundred and twenty-four P multocida isolates were tested, 58 were type strains and 66 were field isolates. Analysis of these strains indicated the assay had a specificity of 99 per cent and sensitivity of at least 86 per cent. The sensitivity could be an underestimate, as five isolates assumed to be false negative reactions may not all be HS-causing strains. The HS ELISA provides a rapid, simple, accurate and inexpensive diagnostic assay for identification of HS causing organisms but does not represent a new typing system for P multocida. This assay will also enable countries to assess the impact of HS more accurately.

Pasteurella multocida infections in mice with reference to haemorrhagic septicaemia in cattle and buffalo

Haemorrhagic septicaemia (HS) is an infectious disease of cattle and buffalo caused by particular serotypes of Pasteurella multocida and is one of the most economically important livestock diseases in South-East Asia. While HS has been recognized for many years, very little is understood about the disease, primarily because of the expense of cattle and a lack of suitable animal models. The suitability of using mice to study HS was assessed using parameters such as the critical pathogenic dose, kinetics of infection, pathology of disease and resistance to reinfection. Pasteurella multocida M1404, the type strain for Carter group B, the serotype responsible for Asian HS, was injected intraperitoneally into BALB/c mice. As few as 20 colony forming units produced an overwhelming septicaemia in mice in less than 30 h. The kinetics of infection demonstrated a very rapid in vivo multiplication rate. There was no evidence of inhibition of bacterial cell growth by natural host defence mechanisms, even with the very small inocula used. The gross pathology of the disease in mice was characterized by splenomegaly, lymphadenopathy and petechial haemorrhages similar to that observed in cattle and buffalo with HS. Mice were found to develop a short-lived resistance to reinfection following a primary infection which had been successfully treated with antibiotics. The mouse would seem to provide an ideal tool by which to study HS, but warrant further studies in order to be able to critically assess it as a model for this economically important disease.

Evaluation of bovine antibody responses to haemorrhagic septicaemia vaccine

ELISA and immunoblotting techniques were used to examine the humoral immune response to Pasteurella multocida, in bovine sera from Indonesia and Malaysia. Elevated levels of antibody to a crude lipopolysaccharide preparation were found in vaccinated animals. In addition to the response to lipopolysaccharide, antibodies from the vaccinated cattle strongly labelled five to six of the 40 protein bands in this organism.

Large DNA separation using field alternation agar gel electrophoresis

The techniques for large DNA separation have developed from a seminal idea for field alternation which has transformed the field of DNA electrophoresis. This single innovation of pulsed field-gradient electrophoresis (PFGE) and the subsequent modifications have made a significant impact on molecular biology, eukaryote genetics, biopolymer research and diagnostic research. The apparatus types used for large DNA separation are depicted and critically compared with relation to molecular mass separation capabilities, straight-lane migration of samples, band sharpness and ease of operation. With these criteria in mind PFGE and orthogonal field alternation gel electrophoresis systems had a number of drawbacks, the principle one being the inability of these systems to give straight-lane migration. To a large extent this has restricted the widespread use of these systems. Field inversion gel electrophoresis produces straight-lane migration but was subject to an upper molecular mass limitation of 2 megabase pairs and tended to produce broader bands in the higher-molecular-mass areas. Transverse alternating field electrophoresis, rotating gel electrophoresis and contour-clamped homogeneous electric field electrophoresis systems where superior to all the other systems. They gave straight-lane migration, separation of chromosomes up to 10 megabase pairs, good resolution of bands and were all relatively simple to operate. Very little was found to separate these three electrophoresis systems. Field alternation electrophoresis has enabled a 500-fold increase in the size of DNA molecules that can be resolved in agar gels. Consequently, electrophoretic karyotypes of a number of organisms have been produced, while genome maps, gene locations and sequences of large areas of mammalian genomes are now being undertaken. The ability to separate entire chromosomes or large DNA fragments has, in conjunction with novel molecular biology techniques, enabled scientists to work backwards from large purified fragments or entire chromosomes to construct long-range genetic maps. The time saving alone when compared with the old techniques of using very small fragments to construct a picture of the gene or gene complex is commendable. The diagnostic role of large DNA separation and electrophoretic karyotyping is beginning to be explored, while the use of this technique for clinical studies of genetic disorders is well advanced. Very few innovations in nucleic acid separation have had as marked an influence on as many areas as field alternation electrophoresis. These techniques have brought mapping of the mammalian genome into the realms of possibility and is contributing in many sphere

Eosinophil responses in sheep selected for high and low responsiveness to Trichostrongylus colubriformis

A breeding programme, based on selection for faecal egg counts, has produced lines of sheep which demonstrate either increased resistance (high responder) or susceptibility (low responder) to challenge infection with T. colubriformis after vaccination with irradiated larvae. Circulating blood eosinophilia, a hallmark of helminth infections, was examined in third generation lambs from two separate selective matings and random bred control lambs. Numbers of eosinophils were higher in high responder lambs when compared to low responders after vaccination and challenge infections. Analysis of eosinophil counts confirmed a strong line effect and there was no evidence of a sex effect. Random bred lambs showed wide individual variations in eosinophil numbers and their response to infection. It was concluded that peripheral eosinophilia was more a measure of host responsiveness to infection than an indicator of helminthiasis. As such the eosinophil may serve as an indicator of the hosts ability to respond to T. colubriformis vaccination and infection.

The isolation of nucleic acid from nematodes requires an understanding of the parasite and its cuticular structure

As parasitology increasingly becomes the domain of molecular biologists, it is important to keep in mind that a fundamental understanding of the whole parasite, its structure and behaviour can help to solve complex problems of molecular biology. Hugh Dawkins and Terence Spencer discuss the preparation of DNA from filaform larvae of Trichostrongylus colubriformis and Ostertagia circumcincta and how a detailed knowledge of the morphology and life cycle of each parasite helps in this process.

Field inversion gel electrophoresis (FIGE) in vertical slabs as an improved method for large DNA separation

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Molecular weight separation of very large DNA

Gel electrophoresis has many applications in parasitology, especially for the separation of enzymes, immunoglobulins and DNA, but the ability to separate molecules based on size is usually restricted to within the upper and lower ranges o f molecular weight. These limitations are particularly evident in mocromolecular DNA electrophoresis, although recent innovations in ogorose gel electrophoresis have substantially reduced these boundaries and are permitting the separation of very large DNA molecules and intact chromosomes of many organisms. In this article, Hugh Dawkins explains these techniques and their principle variants.

Interactions of Strongyloides ratti free-living and skin-penetrated infective larvae and parasitic adults with serum and cells in vitro

When Strongyloides ratti free-living infective larvae were incubated with peritoneal exudate cells from normal or previously infected mice, cell attachment occurred only in the presence of normal (NMS) or immune mouse serum (IMS). This non-specific effect was transitory with larvae being alive and free of cells 24 h after incubation. Cell attachment was mediated by complement. When incubated with infective larvae which had penetrated mouse skin, both normal and immune cells attached to larvae in the absence of serum. This effect was again transitory except when immune cells or immune serum were present, indicating a specific immunological mechanism. Again, larvae remained viable. When incubated with isolated parasitic adult worms, persistent cell attachment occurred in the presence of immune serum, immune cells or both, but all worms remained viable. This system provides a means for investigating the mechanisms of resistance to reinfection in strongyloidiasis.

Kinetics of intestinal lamina propria mast cells, globule leucocytes, intraepithelial lymphocytes, goblet cells and eosinophils in murine strongyloidiasis

The changes in numbers of 6 cell populations in the intestine of mice at various intervals after primary and challenge infections with Strongyloides ratti have been quantified. The number of lamina propria mast cells increased 8 days after primary infection and reached a peak at 12 days. After secondary infection, there was a transient fall in mast cell numbers followed by a slow increase. Globule leucocytes showed a similar trend early in the primary infection and had reached normal levels after 28 days. After challenge infection, there was an early and rapid increase in their numbers. Granular intraepithelial lymphocytes did not alter significantly during the first 14 days, but were significantly greater 28 days after primary infection; they did not vary significantly after challenge infection. However, numbers of non-granular intraepithelial lymphocytes increased 10 days after infection, were elevated prior to the secondary infection at 28 days, then declined in numbers nearly 2 weeks after challenge infection. Goblet cells increased significantly 12 days after primary infection then declined rapidly. After challenge infection, there was an accelerated increase in numbers. Eosinophil numbers increased 4 days after infection, reached a peak at 12 days and then declined. After challenge infection, there was an augmented and accelerated increase in eosinophil numbers followed by rapid decline. The role of the various cells types in host defences against worms or in containment of the inflammatory responses evoked by these parasites are discussed.

Infections with a Malaysian dog strain of Ancylostoma ceylanicum in outbred, inbred and immunocompromised mice

The course of infection with a Malaysian dog strain of Ancylostoma ceylanicum was investigated in 15 inbred strains of mice, in outbred and inbred mice immunosuppressed with prednisolone, and in immunodeficient hypothymic mice. Oral, percutaneous and subcutaneous routes of infection, in both sexes of mice, were assessed. In only one instance was a single small adult male worm found. Following oral infection, larvae migrated from the stomach to the large bowel and then a proportion of worms penetrated the perianal skin. This was followed by the appearance of larvae in the lungs. Living 3rd-stage larvae were seen in the anterior small intestine, perianal skin and lungs for the 6 weeks of the study, with peak recoveries being at 12 h, 8 days and 3 weeks, respectively. It is clear that systemic migration of larvae occurs after oral infection, and it is possible that recirculation may occur. Only a small percentage of larvae penetrated the abdominal skin after being administered percutaneously. In subcutaneous infections, a small proportion of larvae moved rapidly from the site of injection and were recovered from the lungs 2 h after infection. Most larvae, however, migrated from the injection site over the ensuing few days. Living 3rd-stage larvae were seen in the lungs and in the small intestine for the 4 weeks of observation. The strain of A. ceylanicum employed does not complete its development in mice. Nevertheless, this model offers significant potential for studying the immune responses, as well as investigating the means by which these parasites evade host defences.

Light and electron microscopical studies of the location of Strongyloides ratti in the mouse intestine

This study was designed to define the precise anatomical location of Strongyloides ratti in the intestinal mucosa of the mouse. Light microscopy showed adult worms in vacuoles in close relationship with the columnar epithelium. Serial sections indicated that the adults wound their way circuitously through the mucosa, usually close to the crypts. Portions of worms were sometimes seen in the intestinal lumen. Electron microscopy demonstrated that adult worms were situated between the epithelial cells. They were never observed to penetrate the basement lamina and enter the lamina propria. Enterocytes were in close proximity to the cephalic end of worms, suggesting that the head of the moving worm forced the cells apart. More posteriorly along the worm, a fluid-filled vacuole surrounded the nematode. The surrounding epithelial cells were compressed and distorted but there was never any evidence of syncytial cell formation. The external cortical layer of worms was seen in some vacuoles, suggesting that ecdysis may occur in tunnels in the epithelium. It appears that S. ratti may create epithelial tunnels through which it moves, moults and deposits eggs. Since S. ratti is a mucosal-dwelling parasite, it is susceptible to attack by cellular elements of the host's defences.

Humoral and cell-mediated immune responses in murine strongyloidiasis

The immunological changes occurring after primary and challenge infections with Strongyloides ratti in C57B1/6 mice are described. Serum IgM and IgG antibodies against Strongyloides antigen appeared one week after primary infection. The levels of antibody in both immunoglobulin classes increased markedly after secondary infection and persisted for at least 6 weeks. Immediate hypersensitivity (15 min footpad) reactions were transient after a primary infection, but were marked and persistent after a secondary infection. Arthus (5 h footpad) reactions were mild and very transient after a primary infection, but a persistent anamnestic response was seen after challenge infection. Cell-mediated immune (24 h footpad) reactions were marked 1 week after both primary and secondary infections but were not sustained in either case. Antigen-reactive cells were present in the mesenteric lymph nodes 1 week after primary infection and 1-4 weeks after challenge infection. No antigen-reactive cells were noted in the spleen. Mesenteric lymph node (MLN) cells and spleen cells from infected or uninfected animals were stimulated with phytohaemagglutinin (PHA) or lipopolysaccharide (LPS) but did not differ significantly in their 3H thymidine incorporation. A transient eosinophilia was observed after primary infection and an anamnestic response was noted after challenge infection. The possible roles of these immunological responses to worm rejection and immunopathology are considered.